CT fluoroscopy-guided robotically-assisted lung biopsy

NASA Astrophysics Data System (ADS)

Xu, Sheng; Fichtinger, Gabor; Taylor, Russell H.; Banovac, Filip; Cleary, Kevin

2006-03-01

Lung biopsy is a common interventional radiology procedure. One of the difficulties in performing the lung biopsy is that lesions move with respiration. This paper presents a new robotically assisted lung biopsy system for CT fluoroscopy that can automatically compensate for the respiratory motion during the intervention. The system consists of a needle placement robot to hold the needle on the CT scan plane, a radiolucent Z-frame for registration of the CT and robot coordinate systems, and a frame grabber to obtain the CT fluoroscopy image in real-time. The CT fluoroscopy images are used to noninvasively track the motion of a pulmonary lesion in real-time. The position of the lesion in the images is automatically determined by the image processing software and the motion of the robot is controlled to compensate for the lesion motion. The system was validated under CT fluoroscopy using a respiratory motion simulator. A swine study was also done to show the feasibility of the technique in a respiring animal.

Radiation exposure from fluoroscopy during orthopedic surgical procedures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Riley, S.A.

1989-11-01

The use of fluoroscopy has enabled orthopedic surgeons to become technically more proficient. In addition, these surgical procedures tend to have less associated patient morbidity by decreasing operative time and minimizing the area of the operative field. The trade-off, however, may be an increased risk of radiation exposure to the surgeon on an annual or lifetime basis. The current study was designed to determine the amount of radiation received by the primary surgeon and the first assistant during selected surgical procedures involving the use of fluoroscopy. Five body sites exposed to radiation were monitored for dosage. The results of thismore » study indicate that with appropriate usage, (1) radiation exposure from fluoroscopy is relatively low; (2) the surgeon's dominant hand receives the most exposure per case; and (3) proper maintenance and calibration of fluoroscopic machines are important factors in reducing exposure risks. Therefore, with proper precautions, the use of fluoroscopy in orthopedic procedures can remain a safe practice.« less

Performance evaluation of image-intensifier-TV fluoroscopy systems

NASA Astrophysics Data System (ADS)

van der Putten, Wilhelm J.; Bouley, Shawn

1995-05-01

Through use of a computer model and an aluminum low contrast phantom developed in-house, a method has been developed which is able to grade the imaging performance of fluoroscopy systems through use of a variable, K. This parameter was derived from Rose's model of image perception and is here used as a figure of merit to grade fluoroscopy systems. From Rose's model for an ideal system, a typical value of K for the perception of low contrast details should be between 3 and 7, assuming threshold vision by human observers. Thus, various fluoroscopy systems are graded with different values of K, with a lower value of K indicating better imaging performance of the system. A series of fluoroscopy systems have been graded where the best system produces a value in the low teens, while the poorest systems produce a value in the low twenties. Correlation with conventional image quality measurements is good and the method has the potential for automated assessment of image quality.

Digital methods for reducing radiation exposure during medical fluoroscopy

NASA Astrophysics Data System (ADS)

Edmonds, Ernest W.; Rowlands, John A.; Hynes, David M.; Toth, B. D.; Porter, Anthony J.

1990-07-01

There is increased concern over radiation exposure to the general population from many sources. One of the most significant sources is that received by the patient during medical diagnostic procedures, and of these, the procedure with the greatest potential hazard is fluoroscopy. The legal limit for fluoroscopy in most jurisdictions is SR per minute skin exposure rate. Fluoroscopes are often operated in excess of this figure, and in the case of interventional procedures, fluorocopy times may exceed 20 minutes. With improvements in medical technology these procedures are being performed more often, and also are being carried out on younger age groups. Radiation exposure during fluoroscopy, both to patient and operator, is therefore becoming a matter of increasing concern to regulating authorities, and it is incumbent on us to develop digital technology to minimise the radiation hazard in these procedures. This paper explores the technical options available for radiation exposure reduction, including pulsed fluoroscopy, digital noise reduction, or simple reduction in exposure rate to the x-ray image intensifier. We also discuss educational aspects of fluoroscopy which radiologists should be aware of which can be more important than the technological solutions. A "work in progress" report gives a completely new approach to the implementation of a large number of possible digital algorithms, for the investigation of clinical efficacy.

The use of computerized image guidance in lumbar disk arthroplasty.

PubMed

Smith, Harvey E; Vaccaro, Alexander R; Yuan, Philip S; Papadopoulos, Stephen; Sasso, Rick

2006-02-01

Surgical navigation systems have been increasingly studied and applied in the application of spinal instrumentation. Successful disk arthroplasty requires accurate midline and rotational positioning for optimal function and longevity. A surgical simulation study in human cadaver specimens was done to evaluate and compare the accuracy of standard fluoroscopy, computer-assisted fluoroscopic image guidance, and Iso-C3D image guidance in the placement of lumbar intervertebral disk replacements. Lumbar intervertebral disk prostheses were placed using three different image guidance techniques in three human cadaver spine specimens at multiple levels. Postinstrumentation accuracy was assessed with thin-cut computed tomography scans. Intervertebral disk replacements placed using the StealthStation with Iso-C3D were more accurately centered than those placed using the StealthStation with FluoroNav and standard fluoroscopy. Intervertebral disk replacements placed with Iso-C3D and FluoroNav had improved rotational divergence compared with standard fluoroscopy. Iso-C3D and FluoroNav had a smaller interprocedure variance than standard fluoroscopy. These results did not approach statistical significance. Relative to both virtual and standard fluoroscopy, use of the StealthStation with Iso-C3D resulted in improved accuracy in centering the lumbar disk prosthesis in the coronal midline. The StealthStation with FluoroNav appears to be at least equivalent to standard fluoroscopy and may offer improved accuracy with rotational alignment while minimizing radiation exposure to the surgeon. Surgical guidance systems may offer improved accuracy and less interprocedure variation in the placement of intervertebral disk replacements than standard fluoroscopy. Further study regarding surgical navigation systems for intervertebral disk replacement is warranted.

Fluoroscopic radiation exposure: are we protecting ourselves adequately?

PubMed

Hoffler, C Edward; Ilyas, Asif M

2015-05-06

While traditional intraoperative fluoroscopy protection relies on thyroid shields and aprons, recent data suggest that the surgeon's eyes and hands receive more exposure than previously appreciated. Using a distal radial fracture surgery model, we examined (1) radiation exposure to the eyes, thyroid, chest, groin, and hands of a surgeon mannequin; (2) the degree to which shielding equipment can decrease exposure; and (3) how exposure varies with fluoroscopy unit size. An anthropomorphic model was fit with radiation-attenuating glasses, a thyroid shield, an apron, and gloves. "Exposed" thermoluminescent dosimeters overlaid the protective equipment at the eyes, thyroid, chest, groin, and index finger while "shielded" dosimeters were placed beneath the protective equipment. Fluoroscopy position and settings were standardized. The mini-c-arm milliampere-seconds were fixed based on the selection of the kilovolt peak (kVp). Three mini and three standard c-arms scanned a model of the patient's wrist continuously for fifteen minutes each. Ten dosimeter exposures were recorded for each c-arm. Hand exposure averaged 31 μSv/min (range, 22 to 48 μSv/min), which was 13.0 times higher than the other recorded exposures. Eye exposure averaged 4 μSv/min, 2.2 times higher than the mean thyroid, chest, and groin exposure. Gloves reduced hand exposure by 69.4%. Glasses decreased eye exposure by 65.6%. There was no significant difference in exposure between mini and standard fluoroscopy. Surgeons' hands receive the most radiation exposure during distal radial plate fixation under fluoroscopy. There was a small but insignificant difference in mean exposure between standard fluoroscopy and mini-fluoroscopy, but some standard units resulted in lower exposure than some mini-units. On the basis of these findings, we recommend routine protective equipment to mitigate exposure to surgeons' hands and eyes, in addition to the thyroid, chest, and groin, during fluoroscopy procedures. Copyright © 2015 by The Journal of Bone and Joint Surgery, Incorporated.

Electromagnetic navigation versus fluoroscopy in aortic endovascular procedures: a phantom study.

PubMed

Tystad Lund, Kjetil; Tangen, Geir Arne; Manstad-Hulaas, Frode

2017-01-01

To explore the possible benefits of electromagnetic (EM) navigation versus conventional fluoroscopy during abdominal aortic endovascular procedures. The study was performed on a phantom representing the abdominal aorta. Intraoperative cone beam computed tomography (CBCT) of the phantom was acquired and merged with a preoperative multidetector CT (MDCT). The CBCT was performed with a reference plate fixed to the phantom that, after merging the CBCT with the MDCT, facilitated registration of the MDCT volume with the EM space. An EM field generator was stationed near the phantom. Navigation software was used to display EM-tracked instruments within the 3D image volume. Fluoroscopy was performed using a C-arm system. Five operators performed a series of renal artery cannulations using modified instruments, alternatingly using fluoroscopy or EM navigation as the sole guidance method. Cannulation durations and associated radiation dosages were noted along with the number of cannulations complicated by loss of guidewire insertion. A total of 120 cannulations were performed. The median cannulation durations were 41.5 and 34.5 s for the fluoroscopy- and EM-guided cannulations, respectively. No significant difference in cannulation duration was found between the two modalities (p = 0.736). Only EM navigation showed a significant reduction in cannulation duration in the latter half of its cannulation series compared with the first half (p = 0.004). The median dose area product for fluoroscopy was 0.0836 [Formula: see text]. EM-guided cannulations required a one-time CBCT dosage of 3.0278 [Formula: see text]. Three EM-guided and zero fluoroscopy-guided cannulations experienced loss of guidewire insertion. Our findings indicate that EM navigation is not inferior to fluoroscopy in terms of the ability to guide endovascular interventions. Its utilization may be of particular interest in complex interventions where adequate visualization or minimal use of contrast agents is critical. In vivo studies featuring an optimized implementation of EM navigation should be conducted.

Risk-benefit analysis of navigation techniques for vertebral transpedicular instrumentation: a prospective study.

PubMed

Noriega, David C; Hernández-Ramajo, Rubén; Rodríguez-Monsalve Milano, Fiona; Sanchez-Lite, Israel; Toribio, Borja; Ardura, Francisco; Torres, Ricardo; Corredera, Raul; Kruger, Antonio

2017-01-01

Pedicle screws in spinal surgery have allowed greater biomechanical stability and higher fusion rates. However, malposition is very common and may cause neurologic, vascular, and visceral injuries and compromise mechanical stability. The purpose of this study was to compare the malposition rate between intraoperative computed tomography (CT) scan assisted-navigation and free-hand fluoroscopy-guided techniques for placement of pedicle screw instrumentation. This is a prospective, randomized, observational study. A total of 114 patients were included: 58 in the assisted surgery group and 56 in the free-hand fluoroscopy-guided surgery group. Analysis of screw position was assessed using the Heary classification. Breach severity was defined according to the Gertzbein classification. Radiation doses were evaluated using thermoluminescent dosimeters, and estimates of effective and organ doses were made based on scan technical parameters. Consecutive patients with degenerative disease, who underwent surgical procedures using the free-hand, or intraoperative navigation technique for placement of transpedicular instrumentation, were included in the study. Forty-four out of 625 implanted screws were malpositioned: 11 (3.6%) in the navigated surgery group and 33 (10.3%) in the free-hand group (p<.001). Screw position according to the Heary scale was Grade II (4 navigated surgery, 6 fluoroscopy guided), Grade III (3 navigated surgery, 11 fluoroscopy guided), Grade IV (4 navigated surgery, 16 fluoroscopy guided), and Grade V (1 fluoroscopy guided). There was only one symptomatic case in the conventional surgery group. Breach severity was seven Grade A and four Grade B in the navigated surgery group, and eight Grade A, 24 Grade B, and one Grade C in free-hand fluoroscopy-guided surgery group. Radiation received per patient was 5.8 mSv (4.8-7.3). The median dose received in the free-hand fluoroscopy group was 1 mGy (0.8-1.1). There was no detectable radiation level in the navigation-assisted surgery group, whereas the effective dose was 10 µGy in the free-hand fluoroscopy-guided surgery group. Malposition rate, both symptomatic and asymptomatic, in spinal surgery is reduced when using CT-guided placement of transpedicular instrumentation compared with placement under fluoroscopic guidance, with radiation values within the safety limits for health. Larger studies are needed to determine risk-benefit in these patients. Copyright © 2016 Elsevier Inc. All rights reserved.

Radiation exposure, and procedure and fluoroscopy times in endovascular treatment of intracranial aneurysms: a methodological comparison.

PubMed

Cheung, Nicholas K; Boutchard, Michelle; Carr, Michael W; Froelich, Jens J

2018-01-09

Limited data are available for radiation exposure, and procedure and fluoroscopy times in neuroendovascular treatment (NET) strategies. This study establishes and compares related parameters between coil embolization (COIL), balloon assisted coil embolization (BAC), stent assisted coil embolization (SAC), and flow diverting technology (FDT) in NET of intracranial aneurysms. Between 2010 and 2017, 249 consecutive intracranial aneurysms underwent NET at a single center, all performed by the same operator. Dose area products (DAP), and procedure and fluoroscopy times were recorded and compared between COIL, BAC, SAC, and FDT techniques. Differences in parameters between cohorts were analyzed for significance using the Mann-Whitney U test, unpaired t test and χ 2 test. Additional subgroup analysis was performed for emergency and elective cases. 83 aneurysms were treated with COIL (33%), 72 with BAC (29%), 61 with SAC (25%), and 33 with FDT (13%). Baseline characteristics were largely similar within these groups (P>0.05). Among COIL, BAC, and FDT cohorts, no significant difference was found for mean DAP, or procedure and fluoroscopy times (P>0.05). However, compared with all other cohorts, SAC was associated with a significantly higher DAP and longer procedure and fluoroscopy times (P<0.005). No significant difference was recorded for emergency and elective case subgroups. Compared with other NET strategies, SAC was associated with a significantly higher DAP, and longer procedure and fluoroscopy times. This study provides an initial dataset regarding radiation exposure, and procedure and fluoroscopy times for common NET, and may assist ALARA (As Low As Reasonably Achievable) principles to reduce radiation risks. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Fluoroscopy

MedlinePlus

... through a clinical facility’s quality assurance program, are fundamental to radiation protection. More information about the principles ... as part of quality assurance program emphasizing radiation management. Health care providers who use fluoroscopy should be ...

Reduction of radiation exposure while maintaining high-quality fluoroscopic images during interventional cardiology using novel x-ray tube technology with extra beam filtering.

PubMed

den Boer, A; de Feyter, P J; Hummel, W A; Keane, D; Roelandt, J R

1994-06-01

Radiographic technology plays an integral role in interventional cardiology. The number of interventions continues to increase, and the associated radiation exposure to patients and personnel is of major concern. This study was undertaken to determine whether a newly developed x-ray tube deploying grid-switched pulsed fluoroscopy and extra beam filtering can achieve a reduction in radiation exposure while maintaining fluoroscopic images of high quality. Three fluoroscopic techniques were compared: continuous fluoroscopy, pulsed fluoroscopy, and a newly developed high-output pulsed fluoroscopy with extra filtering. To ascertain differences in the quality of images and to determine differences in patient entrance and investigator radiation exposure, the radiated volume curve was measured to determine the required high voltage levels (kVpeak) for different object sizes for each fluoroscopic mode. The fluoroscopic data of 124 patient procedures were combined. The data were analyzed for radiographic projections, image intensifier field size, and x-ray tube kilovoltage levels (kVpeak). On the basis of this analysis, a reference procedure was constructed. The reference procedure was tested on a phantom or dummy patient by all three fluoroscopic modes. The phantom was so designed that the kilovoltage requirements for each projection were comparable to those needed for the average patient. Radiation exposure of the operator and patient was measured during each mode. The patient entrance dose was measured in air, and the operator dose was measured by 18 dosimeters on a dummy operator. Pulsed compared with continuous fluoroscopy could be performed with improved image quality at lower kilovoltages. The patient entrance dose was reduced by 21% and the operator dose by 54%. High-output pulsed fluoroscopy with extra beam filtering compared with continuous fluoroscopy improved the image quality, lowered the kilovoltage requirements, and reduced the patient entrance dose by 55% and the operator dose by 69%. High-output pulsed fluoroscopy with a grid-switched tube and extra filtering improves the image quality and significantly reduces both the operator dose and patient dose.

Fluoroscopy Learning Curve in Hip Arthroscopy-A Single Surgeon's Experience.

PubMed

Smith, Kevin M; Duplantier, Neil L; Crump, Kimbelyn H; Delgado, Domenica A; Sullivan, Stephanie L; McCulloch, Patrick C; Harris, Joshua D

2017-10-01

To determine if (1) absorbed radiation dose and (2) fluoroscopy time decreased with experience over the first 100 cases of a single surgeon's hip arthroscopy practice. Subjects who underwent hip arthroscopy for symptomatic femoroacetabular impingement and labral injury were eligible for analysis. Inclusion criteria included the first 100 subjects who underwent hip arthroscopy by a single surgeon (December 2013 to December 2014). Subject demographics, procedure details, fluoroscopy absorbed dose (milligray [mGy]), and time were recorded. Subjects were categorized by date of surgery to one of 4 possible groups (25 per group). One-way analysis of variance was used to determine if a significant difference in dose (mGy) or time was present between groups. Simple linear regression analysis was performed to determine the relation between case number and both radiation dose and fluoroscopy time. Subjects underwent labral repair (n = 93), cam osteoplasty (n = 90), and pincer acetabuloplasty (n = 65). There was a significant (P < .001 for both) linear regression between case number and both radiation dose and fluoroscopy time. A significant difference in mGy was observed between groups, group 1 the highest and group 4 the lowest amounts of radiation (P = .003). Comparing individual groups, group 4 was found to have a significantly lower amount of radiation than group 1 (P = .002), though it was not significantly lower than that of group 2 (P = .09) or group 3 (P = .08). A significant difference in fluoroscopy time was observed between groups, group 1 the highest and group 4 the lowest times (P = .05). Comparing individual groups, group 4 was found to have a significantly lower fluoroscopy time than group 1 (P = .039). Correction for weight, height, and body mass index all revealed the same findings: significant (P < .05) differences in both dose and time across groups. The absorbed dose of radiation and fluoroscopy time decreased significantly over the first 100 cases of a single surgeon's hip arthroscopy practice learning curve. Level IV, therapeutic, retrospective, noncomparative case series. Copyright © 2017 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

A simple ergonomic measure reduces fluoroscopy time during ERCP: A multivariate analysis.

PubMed

Jowhari, Fahd; Hopman, Wilma M; Hookey, Lawrence

2017-03-01

Background and study aims  Endoscopic retrograde cholangiopancreatgraphy (ERCP) carries a radiation risk to patients undergoing the procedure and the team performing it. Fluoroscopy time (FT) has been shown to have a linear relationship with radiation exposure during ERCP. Recent modifications to our ERCP suite design were felt to impact fluoroscopy time and ergonomics. This multivariate analysis was therefore undertaken to investigate these effects, and to identify and validate various clinical, procedural and ergonomic factors influencing the total fluoroscopy time during ERCP. This would better assist clinicians with predicting prolonged fluoroscopic durations and to undertake relevant precautions accordingly. Patients and methods  A retrospective analysis of 299 ERCPs performed by 4 endoscopists over an 18-month period, at a single tertiary care center was conducted. All inpatients/outpatients (121 males, 178 females) undergoing ERCP for any clinical indication from January 2012 to June 2013 in the chosen ERCP suite were included in the study. Various predetermined clinical, procedural and ergonomic factors were obtained via chart review. Univariate analyses identified factors to be included in the multivariate regression model with FT as the dependent variable. Results  Bringing the endoscopy and fluoroscopy screens next to each other was associated with a significantly lesser FT than when the screens were separated further (-1.4 min, P  = 0.026). Other significant factors associated with a prolonged FT included having a prior ERCP (+ 1.4 min, P  = 0.031), and more difficult procedures (+ 4.2 min for each level of difficulty, P  < 0.001). ERCPs performed by high-volume endoscopists used lesser FT vs. low-volume endoscopists (-1.82, P = 0.015). Conclusions  Our study has identified and validated various factors that affect the total fluoroscopy time during ERCP. This is the first study to show that decreasing the distance between the endoscopy and fluoroscopy screens in the ERCP suite significantly reduces the total fluoroscopy time, and therefore radiation exposure to patients and staff involved in the procedure.

Placement of iliosacral screws using 3D image-guided (O-Arm) technology and Stealth Navigation: comparison with traditional fluoroscopy.

PubMed

Theologis, A A; Burch, S; Pekmezci, M

2016-05-01

We compared the accuracy, operating time and radiation exposure of the introduction of iliosacral screws using O-arm/Stealth Navigation and standard fluoroscopy. Iliosacral screws were introduced percutaneously into the first sacral body (S1) of ten human cadavers, four men and six women. The mean age was 77 years (58 to 85). Screws were introduced using a standard technique into the left side of S1 using C-Arm fluoroscopy and then into the right side using O-Arm/Stealth Navigation. The radiation was measured on the surgeon by dosimeters placed under a lead thyroid shield and apron, on a finger, a hat and on the cadavers. There were no neuroforaminal breaches in either group. The set-up time for the O-Arm was significantly longer than for the C-Arm, while total time for placement of the screws was significantly shorter for the O-Arm than for the C-Arm (p = 0.001). The mean absorbed radiation dose during fluoroscopy was 1063 mRad (432.5 mRad to 4150 mRad). No radiation was detected on the surgeon during fluoroscopy, or when he left the room during the use of the O-Arm. The mean radiation detected on the cadavers was significantly higher in the O-Arm group (2710 mRem standard deviation (sd) 1922) than during fluoroscopy (11.9 mRem sd 14.8) (p < 0.01). O-Arm/Stealth Navigation allows for faster percutaneous placement of iliosacral screws in a radiation-free environment for surgeons, albeit with the same accuracy and significantly more radiation exposure to cadavers, when compared with standard fluoroscopy. Placement of iliosacral screws with O-Arm/Stealth Navigation can be performed safely and effectively. Cite this article: Bone Joint J 2016;98-B:696-702. ©2016 The British Editorial Society of Bone & Joint Surgery.

Implementation of a near-zero fluoroscopy approach in interventional electrophysiology: impact of operator experience.

PubMed

Wannagat, Severin; Loehr, Lena; Lask, Sebastian; Völk, Katharina; Karaköse, Tamer; Özcelik, Cemil; Mügge, Andreas; Wutzler, Alexander

2018-04-01

Catheter ablation is performed under fluoroscopic guidance. Reduction of radiation dose for patients and staff is emphasized by current recommendations. Previous studies have shown that lower operator experience leads to increased radiation dose. On the other hand, less experienced operators may depend even more on fluoroscopic guidance. Our study aimed to evaluate feasibility and efficacy of a non-fluoroscopic approach in different training levels. From January 2017, a near-zero fluoroscopy approach was established in two centers. Four operators (beginner, 1st year fellow, 2nd year fellow, expert) were instructed to perform the complete procedure with the use of a 3-D mapping system without fluoroscopy. A historical cohort that underwent procedures with fluoroscopy use served as control group. Dose area product (DPA), procedure duration, acute procedural success, and complications were compared between the groups and for each operator. Procedures were performed in 157 patients. The first 100 patients underwent procedures with fluoroscopic guidance, the following 57 procedures were performed with the near-zero fluoroscopy approach. The results show a significant reduction in DPA for all operators immediately after implementation of the near-zero fluoroscopy protocol (control 637 ± 611 μGy/m 2 ; beginner 44.1 ± 79.5 μGy/m 2 , p = 0.002; 1st year fellow 24.3 ± 46.4.5 μGy/m 2 , p = 0.001; 2nd year fellow 130.3 ± 233.3 μGy/m 2 , p = 0.003; expert 9.3 ± 37.4 μGy/m 2 , P < 0.001). Procedure duration, acute success, and complications were not significantly different between the groups. Our results show a 90% reduction of DPA shortly after implementation of a near-zero fluoroscopy approach in interventional electrophysiology even in operators in training.

C-arm positioning using virtual fluoroscopy for image-guided surgery

NASA Astrophysics Data System (ADS)

de Silva, T.; Punnoose, J.; Uneri, A.; Goerres, J.; Jacobson, M.; Ketcha, M. D.; Manbachi, A.; Vogt, S.; Kleinszig, G.; Khanna, A. J.; Wolinsky, J.-P.; Osgood, G.; Siewerdsen, J. H.

2017-03-01

Introduction: Fluoroscopically guided procedures often involve repeated acquisitions for C-arm positioning at the cost of radiation exposure and time in the operating room. A virtual fluoroscopy system is reported with the potential of reducing dose and time spent in C-arm positioning, utilizing three key advances: robust 3D-2D registration to a preoperative CT; real-time forward projection on GPU; and a motorized mobile C-arm with encoder feedback on C-arm orientation. Method: Geometric calibration of the C-arm was performed offline in two rotational directions (orbit α, orbit β). Patient registration was performed using image-based 3D-2D registration with an initially acquired radiograph of the patient. This approach for patient registration eliminated the requirement for external tracking devices inside the operating room, allowing virtual fluoroscopy using commonly available systems in fluoroscopically guided procedures within standard surgical workflow. Geometric accuracy was evaluated in terms of projection distance error (PDE) in anatomical fiducials. A pilot study was conducted to evaluate the utility of virtual fluoroscopy to aid C-arm positioning in image guided surgery, assessing potential improvements in time, dose, and agreement between the virtual and desired view. Results: The overall geometric accuracy of DRRs in comparison to the actual radiographs at various C-arm positions was PDE (mean ± std) = 1.6 ± 1.1 mm. The conventional approach required on average 8.0 ± 4.5 radiographs spent "fluoro hunting" to obtain the desired view. Positioning accuracy improved from 2.6o ± 2.3o (in α) and 4.1o ± 5.1o (in β) in the conventional approach to 1.5o ± 1.3o and 1.8o ± 1.7o, respectively, with the virtual fluoroscopy approach. Conclusion: Virtual fluoroscopy could improve accuracy of C-arm positioning and save time and radiation dose in the operating room. Such a system could be valuable to training of fluoroscopy technicians as well as intraoperative use in fluoroscopically guided procedures.

Endoscopic bronchial occlusion for postoperative persistent bronchopleural fistula with computed tomography fluoroscopy guidance and virtual bronchoscopic navigation

PubMed Central

Yanagiya, Masahiro; Matsumoto, Jun; Nagano, Masaaki; Kusakabe, Masashi; Matsumoto, Yoko; Furukawa, Ryutaro; Ohara, Sayaka; Usui, Kazuhiro

2018-01-01

Abstract Rationale: The development of postoperative bronchopleural fistula (BPF) remains a challenge in thoracic surgery. We herein report a case of BPF successfully treated with endoscopic bronchial occlusion under computed tomography (CT) fluoroscopy and virtual bronchoscopic navigation (VBN). Patient concerns: A 63-year-old man underwent right upper lobectomy with concomitant S6a subsegmentectomy for lung adenocarcinoma. On postoperative day 24, he complained of shaking chills with high fever. Diagnoses: BPF with subsequent pneumonia and empyema. Interventions: Despite aggressive surgical interventions for the BPF, air leakage persisted postoperatively. On days 26 and 34 after the final operation, endobronchial occlusions were performed under CT fluoroscopy and VBN. Outcomes: The air leaks greatly decreased and the patient was discharged. Lessons: CT fluoroscopy and VBN can be useful techniques for endobronchial occlusion in the treatment of BPF. PMID:29443771

Endoscopic retrograde JJ-stenting of the ureter without fluoroscopy guidance--an appraisal of outcome.

PubMed

Shuaibu, S I; Gidado, S; Oseni-Momodu, E

2013-01-01

JJ- ureteral stenting is a means of relieving ureteric obstruction. It is done as a retrograde or antegrade procedure, usually under fluoroscopy guidance. We reviewed our results in 2 independent tertiary health centers in Nigeria which lack fluoroscopy units. A 2 year retrospective review of data of patients who had retrograde JJ- ureteric stenting was done. Data relating to age, indication and outcome of procedure were retrieved and analysed. 22 (71%) patients had successful retrograde JJ- ureteric stenting out of 31 patients who were taken for the procedure. These 22 patients had stenting of 27 ureteric units. Mean age was 48.5 years. Commonest indication was carcinoma of the cervix (31.8%). Commonest complication was irritative lower urinary tract symptoms (43.5%). In spite of inherent complications, JJ-stenting is a simple and safe technique. Therefore, the decision to attempt JJ -stenting in carefully selected patients in the absence of fluoroscopy is acceptable.

Preliminary study of rib articulated model based on dynamic fluoroscopy images

NASA Astrophysics Data System (ADS)

Villard, Pierre-Frederic; Escamilla, Pierre; Kerrien, Erwan; Gorges, Sebastien; Trousset, Yves; Berger, Marie-Odile

2014-03-01

We present in this paper a preliminary study of rib motion tracking during Interventional Radiology (IR) fluoroscopy guided procedures. It consists in providing a physician with moving rib three-dimensional (3D) models projected in the fluoroscopy plane during a treatment. The strategy is to help to quickly recognize the target and the no-go areas i.e. the tumor and the organs to avoid. The method consists in i) elaborating a kinematic model of each rib from a preoperative computerized tomography (CT) scan, ii) processing the on-line fluoroscopy image and iii) optimizing the parameters of the kinematic law such as the transformed 3D rib projected on the medical image plane fit well with the previously processed image. The results show a visually good rib tracking that has been quantitatively validated by showing a periodic motion as well as a good synchronism between ribs.

Does fluoroscopy improve outcomes in paediatric forearm fracture reduction?

PubMed

Menachem, S; Sharfman, Z T; Perets, I; Arami, A; Eyal, G; Drexler, M; Chechik, O

2016-06-01

To compare the radiographic results of paediatric forearm fracture reduced with and without fluoroscopic enhancement to investigate whether fractures reduced under fluoroscopic guidance would have smaller residual deformities and lower rates of re-reduction and surgery. A retrospective cohort analysis was conducted comparing paediatric patients with acute forearm fracture in two trauma centres. Demographics and radiographic data from paediatric forearm fractures treated in Trauma Centre A with the aid of a C-arm fluoroscopy were compared to those treated without fluoroscopy in Trauma Centre B. Re-reduction, late displacement, post-reduction deformity, and need for surgical intervention were compared between the two groups. The cohort included 229 children (175 boys and 54 girls, mean age 9.41±3.2 years, range 1-16 years) with unilateral forearm fractures (83 manipulated with fluoroscopy and 146 without). Thirty-four (15%) children underwent re-reduction procedures in the emergency department. Fifty-three (23%) children had secondary displacement in the cast, of which 18 were operated on, 20 were re-manipulated, and the remaining 15 were kept in the cast with an acceptable deformity. Twenty-nine additional children underwent operation for reasons other than secondary displacement. There were no significant differences in re-reduction and surgery rates or in post-reduction deformities between the two groups. The use of fluoroscopy during reduction of forearm fractures in the paediatric population apparently does not have a significant effect on patient outcomes. Reductions performed without fluoroscopy were comparably accurate in correcting deformities in both coronal and sagittal planes. Copyright © 2016 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

Ultrasound guidance to perform intra-articular injection of gadolinium-based contrast material for magnetic resonance arthrography as an alternative to fluoroscopy: the time is now.

PubMed

Messina, Carmelo; Banfi, Giuseppe; Aliprandi, Alberto; Mauri, Giovanni; Secchi, Francesco; Sardanelli, Francesco; Sconfienza, Luca Maria

2016-05-01

Magnetic resonance (MR) imaging has been definitively established as the reference standard in the evaluation of joints in the body. Similarly, magnetic resonance arthrography has emerged as a technique that has been proven to increase significantly the diagnostic performance if compared with conventional MR imaging, especially when dealing with fibrocartilage and articular cartilage abnormalities. Diluted gadolinium can be injected in the joint space using different approaches: under palpation using anatomic landmarks or using an imaging guidance, such as fluoroscopy, computed tomography, or ultrasound. Fluoroscopy has been traditionally used, but the involvement of ionizing radiation should represent a remarkable limitation of this modality. Conversely, ultrasound has emerged as a feasible, cheap, quick, and radiation-free modality that can be used to inject joints, with comparable accuracy of fluoroscopy. In the present paper, we discuss the advantages and disadvantages of using fluoroscopy or ultrasound in injecting gadolinium-based contrast agents in joints to perform magnetic resonance arthrography, also in view of the new EuroSAFE Imaging initiative promoted by the European Society of Radiology and the recent updates to the European Atomic Energy Community 2013/59 directive on the medical use of ionizing radiation. • Intra-articular contrast agent injection can be performed using different imaging modalities • Fluoroscopy is widely used, but uses ionizing radiation • Ultrasound is an accurate, quick, and radiation-free modality for joint injection • X-rays should be avoided when other radiation-free modalities can be used.

First metatarsal closing base wedge osteotomy using real-time fluoroscopy.

PubMed

Toepp, F C; Salcedo, M

1991-01-01

A minimal incision surgery approach to metatarsus primus adductus is presented. The percutaneous closing base wedge osteotomy is performed using real-time intraoperative fluoroscopy. The advantages and disadvantages of this minimal incision surgical procedure are discussed.

Comparative Prospective Study Reporting Intraoperative Parameters, Pedicle Screw Perforation, and Radiation Exposure in Navigation-Guided versus Non-navigated Fluoroscopy-Assisted Minimal Invasive Transforaminal Lumbar Interbody Fusion

PubMed Central

Kundnani, Vishal; Dutta, Shumayou; Patel, Ankit; Mehta, Gaurav; Singh, Mahendra

2018-01-01

Study Design Prospective cohort study. Purpose To compare intraoperative parameters, radiation exposure, and pedicle screw perforation rate in navigation-guided versus non-navigated fluoroscopy-assisted minimal invasive transforaminal lumbar interbody fusion (MIS TLIF). Overview of Literature The poor reliability of fluoroscopy-guided instrumentation and growing concerns about radiation exposure have led to the development of navigation-guided instrumentation techniques in MIS TLIF. The literature evaluating the efficacy of navigation-guided MIS TLIF is scant. Methods Eighty-seven patients underwent navigation- or fluoroscopy-guided MIS TLIF for symptomatic lumbar/lumbosacral spondylolisthesis. Demographics, intraoperative parameters (surgical time, blood loss), and radiation exposure (sec/mGy/Gy.cm2 noted from C-arm for comparison only) were recorded. Computed tomography was performed in patients in the navigation and non-navigation groups at postoperative 12 months and reviewed by an independent observer to assess the accuracy of screw placement, perforation incidence, location, grade (Mirza), and critical versus non-critical neurological implications. Results Twenty-seven patients (male/female, 11/16; L4–L5/L5–S1, 9/18) were operated with navigation-guided MIS TLIF, whereas 60 (male/female, 25/35; L4–L5/L5–S1, 26/34) with conventional fluoroscopy-guided MIS TILF. The use of navigation resulted in reduced fluoroscopy usage (dose area product, 0.47 Gy.cm2 versus 2.93 Gy.cm2), radiation exposure (1.68 mGy versus 10.97 mGy), and fluoroscopy time (46.5 seconds versus 119.08 seconds), with p-values of <0.001. Furthermore, 96.29% (104/108) of pedicle screws in the navigation group were accurately placed (grade 0) (4 breaches, all grade I) compared with 91.67% (220/240) in the non-navigation group (20 breaches, 16 grade I+4 grade II; p=0.114). None of the breaches resulted in a corresponding neurological deficit or required revision. Conclusions Navigation guidance in MIS TLIF reduced radiation exposure, but the perforation status was not statistically different than that for the fluoroscopy-based technique. Thus, navigation in nondeformity cases is useful for significantly reducing the radiation exposure, but its ability to reduce pedicle screw perforation in nondeformity cases remains to be proven. PMID:29713413

Novel real-time tumor-contouring method using deep learning to prevent mistracking in X-ray fluoroscopy.

PubMed

Terunuma, Toshiyuki; Tokui, Aoi; Sakae, Takeji

2018-03-01

Robustness to obstacles is the most important factor necessary to achieve accurate tumor tracking without fiducial markers. Some high-density structures, such as bone, are enhanced on X-ray fluoroscopic images, which cause tumor mistracking. Tumor tracking should be performed by controlling "importance recognition": the understanding that soft-tissue is an important tracking feature and bone structure is unimportant. We propose a new real-time tumor-contouring method that uses deep learning with importance recognition control. The novelty of the proposed method is the combination of the devised random overlay method and supervised deep learning to induce the recognition of structures in tumor contouring as important or unimportant. This method can be used for tumor contouring because it uses deep learning to perform image segmentation. Our results from a simulated fluoroscopy model showed accurate tracking of a low-visibility tumor with an error of approximately 1 mm, even if enhanced bone structure acted as an obstacle. A high similarity of approximately 0.95 on the Jaccard index was observed between the segmented and ground truth tumor regions. A short processing time of 25 ms was achieved. The results of this simulated fluoroscopy model support the feasibility of robust real-time tumor contouring with fluoroscopy. Further studies using clinical fluoroscopy are highly anticipated.

The Use of Laser Guidance Reduces Fluoroscopy Time for C-Arm Cone-Beam Computed Tomography-Guided Biopsies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kroes, Maarten W., E-mail: Maarten.Kroes@radboudumc.nl; Strijen, Marco J. L. van, E-mail: m.van.strijen@antoniusziekenhuis.nl; Braak, Sicco J., E-mail: sjbraak@gmail.com

2016-09-15

PurposeWhen using laser guidance for cone-beam computed tomography (CBCT)-guided needle interventions, planned needle paths are visualized to the operator without the need to switch between entry- and progress-view during needle placement. The current study assesses the effect of laser guidance during CBCT-guided biopsies on fluoroscopy and procedure times.Materials and MethodsProspective data from 15 CBCT-guided biopsies of 8–65 mm thoracic and abdominal lesions assisted by a ceiling-mounted laser guidance technique were compared to retrospective data of 36 performed CBCT-guided biopsies of lesions >20 mm using the freehand technique. Fluoroscopy time, procedure time, and number of CBCT-scans were recorded. All data are presented asmore » median (ranges).ResultsFor biopsies using the freehand technique, more fluoroscopy time was necessary to guide the needle onto the target, 165 s (83–333 s) compared to 87 s (44–190 s) for laser guidance (p < 0.001). Procedure times were shorter for freehand-guided biopsies, 24 min versus 30 min for laser guidance (p < 0.001).ConclusionThe use of laser guidance during CBCT-guided biopsies significantly reduces fluoroscopy time.« less

AAPM/RSNA physics tutorial for residents: physics of flat-panel fluoroscopy systems: Survey of modern fluoroscopy imaging: flat-panel detectors versus image intensifiers and more.

PubMed

Nickoloff, Edward Lee

2011-01-01

This article reviews the design and operation of both flat-panel detector (FPD) and image intensifier fluoroscopy systems. The different components of each imaging chain and their functions are explained and compared. FPD systems have multiple advantages such as a smaller size, extended dynamic range, no spatial distortion, and greater stability. However, FPD systems typically have the same spatial resolution for all fields of view (FOVs) and are prone to ghosting. Image intensifier systems have better spatial resolution with the use of smaller FOVs (magnification modes) and tend to be less expensive. However, the spatial resolution of image intensifier systems is limited by the television system to which they are coupled. Moreover, image intensifier systems are degraded by glare, vignetting, spatial distortions, and defocusing effects. FPD systems do not have these problems. Some recent innovations to fluoroscopy systems include automated filtration, pulsed fluoroscopy, automatic positioning, dose-area product meters, and improved automatic dose rate control programs. Operator-selectable features may affect both the patient radiation dose and image quality; these selectable features include dose level setting, the FOV employed, fluoroscopic pulse rates, geometric factors, display software settings, and methods to reduce the imaging time. © RSNA, 2011.

Fluoroscopy and imageless navigation enable an equivalent reconstruction of leg length and global and femoral offset in THA.

PubMed

Weber, Markus; Woerner, Michael; Springorum, Robert; Sendtner, Ernst; Hapfelmeier, Alexander; Grifka, Joachim; Renkawitz, Tobias

2014-10-01

Restoration of biomechanics is a major goal in THA. Imageless navigation enables intraoperative control of leg length equalization and offset reconstruction. However, the effect of navigation compared with intraoperative fluoroscopy is unclear. We asked whether intraoperative use of imageless navigation (1) improves the relative accuracy of leg length and global and femoral offset restoration; (2) increases the absolute precision of leg length and global and femoral offset equalization; and (3) reduces outliers in a reconstruction zone of ± 5 mm for leg length and global and femoral offset restoration compared with intraoperative fluoroscopy during minimally invasive (MIS) THA with the patient in a lateral decubitus position. In this prospective study a consecutive series of 125 patients were randomized to either navigation-guided or fluoroscopy-controlled THA using sealed, opaque envelopes. All patients received the same cementless prosthetic components through an anterolateral MIS approach while they were in a lateral decubitus position. Leg length, global or total offset (representing the combination of femoral and acetabular offset), and femoral offset differences were restored using either navigation or fluoroscopy. Postoperatively, residual leg length and global and femoral offset discrepancies were analyzed on magnification-corrected radiographs of the pelvis by an independent and blinded examiner using digital planning software. Accuracy was defined as the relative postoperative difference between the surgically treated and the unaffected contralateral side for leg length and offset, respectively; precision was defined as the absolute postoperative deviation of leg length and global and femoral offset regardless of lengthening or shortening of leg length and offset throughout the THA. All analyses were performed per intention-to-treat. Analyzing the relative accuracy of leg length restoration we found a mean difference of 0.2 mm (95% CI, -1.0 to +1.4 mm; p = 0.729) between fluoroscopy and navigation, 0.2 mm (95 % CI, -0.9 to +1.3 mm; p = 0.740) for global offset and 1.7 mm (95 % CI, +0.4 to +2.9 mm; p = 0.008) for femoral offset. For the absolute precision of leg length and global and femoral offset equalization, there was a mean difference of 1.7 ± 0.3 mm (p < 0.001) between fluoroscopy and navigation. The biomechanical reconstruction with a residual leg length and global and femoral offset discrepancy less than 5 mm and less than 8 mm, respectively, succeeded in 93% and 98%, respectively, in the navigation group and in 54% and 95%, respectively, in the fluoroscopy group. Intraoperative fluoroscopy and imageless navigation seem equivalent in accuracy and precision to reconstruct leg length and global and femoral offset during MIS THA with the patient in the lateral decubitus position.

Feasibility of three-dimensional magnetic resonance angiography-fluoroscopy image fusion technique in guiding complex endovascular aortic procedures in patients with renal insufficiency.

PubMed

Schwein, Adeline; Chinnadurai, Ponraj; Shah, Dipan J; Lumsden, Alan B; Bechara, Carlos F; Bismuth, Jean

2017-05-01

Three-dimensional image fusion of preoperative computed tomography (CT) angiography with fluoroscopy using intraoperative noncontrast cone-beam CT (CBCT) has been shown to improve endovascular procedures by reducing procedure length, radiation dose, and contrast media volume. However, patients with a contraindication to CT angiography (renal insufficiency, iodinated contrast allergy) may not benefit from this image fusion technique. The primary objective of this study was to evaluate the feasibility of magnetic resonance angiography (MRA) and fluoroscopy image fusion using noncontrast CBCT as a guidance tool during complex endovascular aortic procedures, especially in patients with renal insufficiency. All endovascular aortic procedures done under MRA image fusion guidance at a single-center were retrospectively reviewed. The patients had moderate to severe renal insufficiency and underwent diagnostic contrast-enhanced magnetic resonance imaging after gadolinium or ferumoxytol injection. Relevant vascular landmarks electronically marked in MRA images were overlaid on real-time two-dimensional fluoroscopy for image guidance, after image fusion with noncontrast intraoperative CBCT. Technical success, time for image registration, procedure time, fluoroscopy time, number of digital subtraction angiography (DSA) acquisitions before stent deployment or vessel catheterization, and renal function before and after the procedure were recorded. The image fusion accuracy was qualitatively evaluated on a binary scale by three physicians after review of image data showing virtual landmarks from MRA on fluoroscopy. Between November 2012 and March 2016, 10 patients underwent endovascular procedures for aortoiliac aneurysmal disease or aortic dissection using MRA image fusion guidance. All procedures were technically successful. A paired t-test analysis showed no difference between preimaging and postoperative renal function (P = .6). The mean time required for MRA-CBCT image fusion was 4:09 ± 01:31 min:sec. Total fluoroscopy time was 20.1 ± 6.9 minutes. Five of 10 patients (50%) underwent stent graft deployment without any predeployment DSA acquisition. Three of six vessels (50%) were cannulated under image fusion guidance without any precannulation DSA runs, and the remaining vessels were cannulated after one planning DSA acquisition. Qualitative evaluation showed 14 of 22 virtual landmarks (63.6%) from MRA overlaid on fluoroscopy were completely accurate, without the need for adjustment. Five of eight incorrect virtual landmarks (iliac and visceral arteries) resulted from vessel deformation caused by endovascular devices. Ferumoxytol or gadolinium-enhanced MRA imaging and image fusion with fluoroscopy using noncontrast CBCT is feasible and allows patients with renal insufficiency to benefit from optimal guidance during complex endovascular aortic procedures, while preserving their residual renal function. Copyright © 2016 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

Intussusception reduction: Effect of air vs. liquid enema on radiation dose.

PubMed

Kaplan, Summer L; Magill, Dennise; Felice, Marc A; Edgar, J Christopher; Anupindi, Sudha A; Zhu, Xiaowei

2017-10-01

Both air and radiopaque liquid contrast are used to reduce ileocolic intussusception under fluoroscopy. Some suggest air lowers radiation dose due to shorter procedure times. However, air enema likely lowers radiation dose regardless of fluoroscopy time due to less density over the automatic exposure control cells. We test the hypothesis that air enema reduction of ileocolic intussusception results in lower radiation dose than liquid contrast enema independent of fluoroscopy time. We describe a role for automatic exposure control in this dose difference. We retrospectively evaluated air and liquid intussusception reductions performed on a single digital fluoroscopic unit during a 26-month period. We compared patient age, weight, gender, exam time of day and year, performing radiologist(s), radiographic image acquisitions, grid and magnification use, fluoroscopy time and dose area product. We compared categorical and continuous variables statistically using chi-square and Mann-Whitney U tests, respectively. The mean dose area product was 2.7-fold lower for air enema, 1.3 ± 0.9 dGy·cm 2 , than for liquid, 3.5 ± 2.5 dGy·cm 2 (P<0.005). The mean fluoroscopy time was similar between techniques. The mean dose area product/min was 2.3-fold lower for air, 0.6 ± 0.2 dGy·cm 2 /min, than for liquid, 1.4 ± 0.5 dGy·cm 2 /min (P<0.001). No group differences were identified in other measured dose parameters. Fluoroscopic intussusception reduction using air enema uses less than half the radiation dose of liquid contrast enema. Dose savings are independent of fluoroscopy time and are likely due to automatic exposure control interaction.

Bench-Top Feasibility Testing of a Novel Percutaneous Renal Access Technique: The Laser Direct Alignment Radiation Reduction Technique (DARRT).

PubMed

Khater, Nazih; Shen, Jim; Arenas, Javier; Keheila, Mohamed; Alsyouf, Muhannad; Martin, Jacob A; Lightfoot, Michelle A; Li, Roger; Olgin, Gaudencio; Smith, Jason C; Baldwin, D Duane

2016-11-01

Traditional techniques for obtaining percutaneous renal access utilize continuous fluoroscopy. In an attempt to minimize radiation exposure, we describe a novel laser direct alignment radiation reduction technique (DARRT) for percutaneous access and test it in a bench-top model. In this randomized-controlled bench-top study, 20 medical personnel obtained renal accesses using both the conventional bullseye technique and the laser DARRT. The primary endpoint was total fluoroscopy time. Secondary endpoints included insertion time, puncture attempts, course corrections, and subjective procedural difficulty. In the laser DARRT, fluoroscopy was used with the C-arm positioned with the laser beam at a 30° angle. The access needle and hub were aligned with the laser beam. Effective caliceal puncture was confirmed with fluoroscopy and direct vision. The Paired samples Wilcoxon signed rank test was used for statistical analysis with significance at p < 0.05. A total of 120 needle placements were recorded. Fluoroscopy time for needle access using the laser DARRT was significantly lower than the bullseye technique in all groups as follows: attendings (7.09 vs 18.51 seconds; p < 0.001), residents (6.55 vs 13.93 seconds; p = 0.001), and medical students (6.69 vs 20.22 seconds; p < 0.001). Students rated the laser DARRT easier to use (2.56 vs 4.89; p < 0.001). No difference was seen in total access time, puncture attempts, or course corrections between techniques. The laser DARRT reduced fluoroscopy time by 63%, compared with the conventional bullseye technique. The least experienced users found the laser DARRT significantly easier to learn. This novel technique is promising and merits additional testing in animal and human models.

CTA with fluoroscopy image fusion guidance in endovascular complex aortic aneurysm repair.

PubMed

Sailer, A M; de Haan, M W; Peppelenbosch, A G; Jacobs, M J; Wildberger, J E; Schurink, G W H

2014-04-01

To evaluate the effect of intraoperative guidance by means of live fluoroscopy image fusion with computed tomography angiography (CTA) on iodinated contrast material volume, procedure time, and fluoroscopy time in endovascular thoraco-abdominal aortic repair. CTA with fluoroscopy image fusion road-mapping was prospectively evaluated in patients with complex aortic aneurysms who underwent fenestrated and/or branched endovascular repair (FEVAR/BEVAR). Total iodinated contrast material volume, overall procedure time, and fluoroscopy time were compared between the fusion group (n = 31) and case controls (n = 31). Reasons for potential fusion image inaccuracy were analyzed. Fusion imaging was feasible in all patients. Fusion image road-mapping was used for navigation and positioning of the devices and catheter guidance during access to target vessels. Iodinated contrast material volume and procedure time were significantly lower in the fusion group than in case controls (159 mL [95% CI 132-186 mL] vs. 199 mL [95% CI 170-229 mL], p = .037 and 5.2 hours [95% CI 4.5-5.9 hours] vs. 6.3 hours (95% CI 5.4-7.2 hours), p = .022). No significant differences in fluoroscopy time were observed (p = .38). Respiration-related vessel displacement, vessel elongation, and displacement by stiff devices as well as patient movement were identified as reasons for fusion image inaccuracy. Image fusion guidance provides added value in complex endovascular interventions. The technology significantly reduces iodinated contrast material dose and procedure time. Copyright © 2014 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

The Advantage of a Ureteroscopic Navigation System with Magnetic Tracking in Comparison with Simulated Fluoroscopy in a Phantom Study.

PubMed

Yoshida, Kenji; Yokomizo, Akira; Matsuda, Tadashi; Hamasaki, Tsutomu; Kondo, Yukihiro; Yamaguchi, Kunihisa; Kanayama, Hiro-Omi; Wakumoto, Yoshiaki; Horie, Shigeo; Naito, Seiji

2015-09-01

To assess whether our ureteroscopic real-time navigation system has the possibility to reduce radiation exposure and improve performance of ureteroscopic maneuvers in surgeons of various ages and experience levels. Our novel ureteroscopic navigation system used a magnetic tracking device to detect the position of the ureteroscope and display it on a three-dimensional image. We recruited 31 urologists from five institutions to perform two tasks. Task 1 consisted of finding three internal markings on the phantom calices. Task 2 consisted of identifying all calices by ureteroscopy. In both tasks, participants performed with simulated fluoroscopy first, followed by our navigation system. Accuracy rates (AR) for identification, required time (T) for completing the task, migration length (ML), and time exposed to simulated fluoroscopy were recorded. The AR, T, and ML for both tasks were significantly better with the navigation system than without it (Task 1 with simulated fluoroscopy vs with navigation: AR 87.1 % vs 98.9%, P=0.003; T 355 s vs 191 s, P<0.0001; ML 4627 mm vs 2701 mm, P<0.0001. Task 2: AR 88.2% vs 96.7%, P=0.011; T 394 s vs 333 s, P=0.027; ML 5966 mm vs 5299 mm, P=0.0006). In both tasks, the participants used the simulated fluoroscopy about 20% of the total task time. Our navigation system, while still under development, could help surgeons of all levels to achieve better performances for ureteroscopic maneuvers compared with using fluoroscopic guidance. It also has the potential to reduce radiation exposure during fluoroscopy.

CT Fluoroscopy-Guided Lung Biopsy with Novel Steerable Biopsy Canula: Ex-Vivo Evaluation in Ventilated Porcine Lung Explants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schaefer, Philipp J., E-mail: jp.schaefer@rad.uni-kiel.de; Fabel, Michael; Bolte, Hendrik

2010-08-15

The purpose was to evaluate ex-vivo a prototype of a novel biopsy canula under CT fluoroscopy-guidance in ventilated porcine lung explants in respiratory motion simulations. Using an established chest phantom for porcine lung explants, n = 24 artificial lesions consisting of a fat-wax-Lipiodol mixture (approx. 70HU) were placed adjacent to sensible structures such as aorta, pericardium, diaphragm, bronchus and pulmonary artery. A piston pump connected to a reservoir beneath a flexible silicone reconstruction of a diaphragm simulated respiratory motion by rhythmic inflation and deflation of 1.5 L water. As biopsy device an 18-gauge prototype biopsy canula with a lancet-like, helicallymore » bended cutting edge was used. The artificial lesions were punctured under CT fluoroscopy-guidance (SOMATOM Sensation 64, Siemens, Erlangen, Germany; 30mAs/120 kV/5 mm slice thickness) implementing a dedicated protocol for CT fluoroscopy-guided lung biopsy. The mean-diameter of the artificial lesions was 8.3 {+-} 2.6 mm, and the mean-distance of the phantom wall to the lesions was 54.1 {+-} 13.5 mm. The mean-displacement of the lesions by respiratory motion was 14.1 {+-} 4.0 mm. The mean-duration of CT fluoroscopy was 9.6 {+-} 5.1 s. On a 4-point scale (1 = central; 2 = peripheral; 3 = marginal; 4 = off target), the mean-targeted precision was 1.9 {+-} 0.9. No misplacement of the biopsy canula affecting adjacent structures could be detected. The novel steerable biopsy canula proved to be efficient in the ex-vivo set-up. The chest phantom enabling respiratory motion and the steerable biopsy canula offer a feasible ex-vivo system for evaluating and training CT fluoroscopy-guided lung biopsy adapted to respiratory motion.« less

Effectiveness of using low rate fluoroscopy to reduce an examiner's radiation dose during lumbar nerve root block.

PubMed

Yamane, Kentaro; Kai, Nobuo; Mazaki, Tetsuro; Miyamoto, Tadashi; Matsushita, Tomohiro

2018-06-13

Long-term exposure to radiation can lead to gene mutations and increase the risk of cancer. Low rate fluoroscopy has the potential to reduce the radiation exposure for both the examiner and the patient during various fluoroscopic procedures. The purpose of this study was to evaluate the impact of low rate fluoroscopy on reducing an examiner's radiation dose during nerve root block. A total of 101 lumbar nerve root block examinations were performed at our institute during a 6-month period. During the first 3 months, low rate fluoroscopy was performed at 7.5 frames/s (FPS) in 54 examinations, while 47 were performed at 15 FPS during the last 3 months. The examiner wore a torso protector, a neck protector, radiation protection gloves, and radiation protection glasses. Optically stimulated luminescence (OSL) dosimeter badges were placed on both the inside and the outside of each protector. The dosimeters were exchanged every month. Radiation doses (mSv) were measured as the integrated radiation quantity every month from the OSL dosimeters. The effective and equivalent doses for the hands, skin, and eyes were investigated. The mean monthly equivalent doses were significantly lower both inside and outside the hand protector for the 7.5 FPS versus 15 FPS (inside; P = 0.021, outside; P = 0.024). There were no significant differences between the two groups for the mean monthly calculated effective dose for each protector's condition. Radiation exposure was significantly reduced for the skin on the examiner's hand when using low rate fluoroscopy at 7.5 FPS, with no noticeable decrease in image quality or prolonged fluoroscopy time. Copyright © 2018. Published by Elsevier B.V.

Factors associated with reduced radiation exposure, cost, and technical difficulty of inferior vena cava filter placement and retrieval.

PubMed

Neill, Matthew; Charles, Hearns W; Pflager, Daniel; Deipolyi, Amy R

2017-01-01

We sought to delineate factors of inferior vena cava filter placement associated with increased radiation and cost and difficult subsequent retrieval. In total, 299 procedures from August 2013 to December 2014, 252 in a fluoroscopy suite (FS) and 47 in the operating room (OR), were reviewed for radiation exposure, fluoroscopy time, filter type, and angulation. The number of retrieval devices and fluoroscopy time needed for retrieval were assessed. Multiple linear regression assessed the impact of filter type, procedure location, and patient and procedural variables on radiation dose, fluoroscopy time, and filter angulation. Logistic regression assessed the impact of filter angulation, type, and filtration duration on retrieval difficulty. Access site and filter type had no impact on radiation exposure. However, placement in the OR, compared to the FS, entailed more radiation (156.3 vs 71.4 mGy; P = 0.001), fluoroscopy time (6.1 vs 2.8 min; P < 0.001), and filter angulation (4.8° vs 2.6°; P < 0.001). Angulation was primarily dependent on filter type ( P = 0.02), with VenaTech and Denali filters associated with decreased angulation (2.2°, 2.4°) and Option filters associated with greater angulation (4.2°). Filter angulation, but not filter type or filtration duration, predicted cases requiring >1 retrieval device ( P < 0.001) and >30 min fluoroscopy time ( P = 0.02). Cost savings for placement in the FS vs OR were estimated at $444.50 per case. In conclusion, increased radiation and cost were associated with placement in the OR. Filter angulation independently predicted difficult filter retrieval; angulation was determined by filter type. Performing filter placement in the FS using specific filters may reduce radiation and cost while enabling future retrieval.

Paediatric dose reduction with the introduction of digital fluorography.

PubMed

Mooney, R B; McKinstry, J

2001-01-01

Fluoroscopy guided examinations in a paediatric X ray department were initially carried out on a unit that used a conventional screen-film combination for spot-films. A new fluoroscopy unit was installed with the facilities of digital fluorography and last image hold. Comparison of equipment performance showed that the dose per image for screen-film and digital fluorography was 3 microGy and 0.4 microGy, respectively. Although the screen-film had superior image quality, the department's radiologist confirmed that digital fluorography provided a diagnostic image. Patient dose measurements showed that introduction of the new unit caused doses to fall by an average of 70%, although fluoroscopy time had not changed significantly. The new unit produced 40% less air kerma during fluoroscopy. The remaining 30% reduction in dose was due to the introduction of digital fluorography and last image hold facilities. It is concluded that the use of digital fluorography can be an effective way of reducing paediatric dose.

Detection of electrophysiology catheters in noisy fluoroscopy images.

PubMed

Franken, Erik; Rongen, Peter; van Almsick, Markus; ter Haar Romeny, Bart

2006-01-01

Cardiac catheter ablation is a minimally invasive medical procedure to treat patients with heart rhythm disorders. It is useful to know the positions of the catheters and electrodes during the intervention, e.g. for the automatization of cardiac mapping. Our goal is therefore to develop a robust image analysis method that can detect the catheters in X-ray fluoroscopy images. Our method uses steerable tensor voting in combination with a catheter-specific multi-step extraction algorithm. The evaluation on clinical fluoroscopy images shows that especially the extraction of the catheter tip is successful and that the use of tensor voting accounts for a large increase in performance.

Computed tomography angiography-fluoroscopy image fusion allows visceral vessel cannulation without angiography during fenestrated endovascular aneurysm repair.

PubMed

Schwein, Adeline; Chinnadurai, Ponraj; Behler, Greg; Lumsden, Alan B; Bismuth, Jean; Bechara, Carlos F

2018-07-01

Fenestrated endovascular aneurysm repair (FEVAR) is an evolving technique to treat juxtarenal abdominal aortic aneurysms (AAAs). Catheterization of visceral and renal vessels after the deployment of the fenestrated main body device is often challenging, usually requiring additional fluoroscopy and multiple digital subtraction angiograms. The aim of this study was to assess the clinical utility and accuracy of a computed tomography angiography (CTA)-fluoroscopy image fusion technique in guiding visceral vessel cannulation during FEVAR. Between August 2014 and September 2016, all consecutive patients who underwent FEVAR at our institution using image fusion guidance were included. Preoperative CTA images were fused with intraoperative fluoroscopy after coregistering with non-contrast-enhanced cone beam computed tomography (syngo 3D3D image fusion; Siemens Healthcare, Forchheim, Germany). The ostia of the visceral vessels were electronically marked on CTA images (syngo iGuide Toolbox) and overlaid on live fluoroscopy to guide vessel cannulation after fenestrated device deployment. Clinical utility of image fusion was evaluated by assessing the number of dedicated angiograms required for each visceral or renal vessel cannulation and the use of optimized C-arm angulation. Accuracy of image fusion was evaluated from video recordings by three raters using a binary qualitative assessment scale. A total of 26 patients (17 men; mean age, 73.8 years) underwent FEVAR during the study period for juxtarenal AAA (17), pararenal AAA (6), and thoracoabdominal aortic aneurysm (3). Video recordings of fluoroscopy from 19 cases were available for review and assessment. A total of 46 vessels were cannulated; 38 of 46 (83%) of these vessels were cannulated without angiography but based only on image fusion guidance: 9 of 11 superior mesenteric artery cannulations and 29 of 35 renal artery cannulations. Binary qualitative assessment showed that 90% (36/40) of the virtual ostia overlaid on live fluoroscopy were accurate. Optimized C-arm angulations were achieved in 35% of vessel cannulations (0/9 for superior mesenteric artery cannulation, 12/25 for renal arteries). Preoperative CTA-fluoroscopy image fusion guidance during FEVAR is a valuable and accurate tool that allows visceral and renal vessel cannulation without the need of dedicated angiograms, thus avoiding additional injection of contrast material and radiation exposure. Further refinements, such as accounting for device-induced aortic deformation and automating the image fusion workflow, will bolster this technology toward optimal routine clinical use. Copyright © 2017 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

Performance of mobile digital X-ray fluoroscopy using a novel flat panel detector for intraoperative use.

PubMed

Jeong, Chang-Won; Ryu, Jong-Hyun; Joo, Su-Chong; Jun, Hong-Young; Heo, Dong-Woon; Lee, Jinseok; Kim, Kyong-Woo; Yoon, Kwon-Ha

2015-01-01

Technologies employing digital X-ray devices are developed for mobile settings. To develop a mobile digital X-ray fluoroscopy (MDF) for intraoperative guidance, using a novel flat panel detector to focus on diagnostics in outpatient clinics, operating and emergency rooms. An MDF for small-scale field diagnostics was configured using an X-ray source and a novel flat panel detector. The imager enabled frame rates reaching 30 fps in full resolution fluoroscopy with maximal running time of 5 minutes. Signal-to-noise (SNR), contrast-to-noise (CNR), and spatial resolution were analyzed. Stray radiation, exposure radiation dose, and effective absorption dose were measured for patients. The system was suitable for small-scale field diagnostics. SNR and CNR were 62.4 and 72.0. Performance at 10% of MTF was 9.6 lp/mm (53 μ m) in the no binned mode. Stray radiation at 100 cm and 150 cm from the source was below 0.2 μ Gy and 0.1 μ Gy. Exposure radiation in radiography and fluoroscopy (5 min) was 10.2 μ Gy and 82.6 mGy. The effective doses during 5-min-long fluoroscopy were 0.26 mSv (wrist), 0.28 mSv (elbow), 0.29 mSv (ankle), and 0.31 mSv (knee). The proposed MDF is suitable for imaging in operating rooms.

Fluoroscopy-guided Sacroiliac Joint Steroid Injection for Low Back Pain in a Patient with Osteogenesis Imperfecta.

PubMed

Dawson, P U; Rose, R E; Wade, N A

2015-09-01

Osteogenesis imperfecta, also known as 'brittle bone disease', is a genetic connective tissue disease. It is characterized by bone fragility and osteopenia (low bone density). In this case, a 57-year old female presented to the University Hospital of the West Indies (UHWI), Physical Medicine and Rehabilitation Clinic with left low back pain rated 6/10 on the numeric rating scale (NRS). Clinically, the patient had sacroiliac joint mediated pain although X-rays did not show the sacroiliac joint changes. Fluoroscopy-guided left sacroiliac joint steroid injection was done. Numeric rating scale and Oswestry Disability Index (ODI) questionnaire were used to evaluate outcome. This was completed at baseline, one week follow-up and at eight weeks post fluoroscopy-guided sacroiliac joint steroid injection. Numeric rating scale improved from 6/10 before the procedure to 0/10 post procedure, and ODI questionnaire score improved from a moderate disability score of 40% to a minimal disability score of 13%. Up to eight weeks, the NRS was 0/10 and ODI remained at minimal disability of 15%. Fluoroscopy-guided sacroiliac joint injection is a known diagnostic and treatment method for sacroiliac joint mediated pain. To our knowledge, this is the first case published on the use of fluoroscopy-guided sacroiliac joint steroid injection in the treatment of sacroiliac joint mediated low back pain in a patient with osteogenesis imperfecta.

Comparison of Fluoroscopy and Computed Tomography for Tracheal Lumen Diameter Measurement and Determination of Intraluminal Stent Size in Healthy Dogs

PubMed Central

Williams, Jackie M.; Krebs, Ingar A.; Riedesel, Elizabeth A.; Zhao, Qianqian

2015-01-01

Tracheal collapse is a progressive airway disease that can ultimately result in complete airway obstruction. Intraluminal tracheal stents are a minimally invasive and viable treatment for tracheal collapse once the disease becomes refractory to medical management. Intraluminal stent size is chosen based on the maximum measured tracheal diameter during maximum inflation. The purpose of this prospective, cross-sectional study was to compare tracheal lumen diameter measurements and subsequent selected stent size using both fluoroscopy and CT and to evaluate inter- and intraobserver variability of the measurements. Seventeen healthy Beagles were anesthetized and imaged with fluoroscopy and CT with positive pressure ventilation to 20 cm H2O. Fluoroscopic and CT maximum tracheal diameters were measured by 3 readers. Three individual measurements were made at 8 pre-determined tracheal sites for dorsoventral (height) and laterolateral (width) dimensions. Tracheal diameters and stent sizes (based on the maximum tracheal diameter + 10%) were analyzed using a linear mixed model. CT tracheal lumen diameters were larger compared to fluoroscopy at all locations. When comparing modalities, fluoroscopic and CT stent sizes were statistically different. Greater overall variation in tracheal diameter measurement (height or width) existed for fluoroscopy compared to CT, both within and among observers. The greater tracheal diameter and lower measurement variability supported the use of CT for appropriate stent selection to minimize complications in veterinary patients. PMID:26784924

Accuracy assessment of fluoroscopy-transesophageal echocardiography registration

NASA Astrophysics Data System (ADS)

Lang, Pencilla; Seslija, Petar; Bainbridge, Daniel; Guiraudon, Gerard M.; Jones, Doug L.; Chu, Michael W.; Holdsworth, David W.; Peters, Terry M.

2011-03-01

This study assesses the accuracy of a new transesophageal (TEE) ultrasound (US) fluoroscopy registration technique designed to guide percutaneous aortic valve replacement. In this minimally invasive procedure, a valve is inserted into the aortic annulus via a catheter. Navigation and positioning of the valve is guided primarily by intra-operative fluoroscopy. Poor anatomical visualization of the aortic root region can result in incorrect positioning, leading to heart valve embolization, obstruction of the coronary ostia and acute kidney injury. The use of TEE US images to augment intra-operative fluoroscopy provides significant improvements to image-guidance. Registration is achieved using an image-based TEE probe tracking technique and US calibration. TEE probe tracking is accomplished using a single-perspective pose estimation algorithm. Pose estimation from a single image allows registration to be achieved using only images collected in standard OR workflow. Accuracy of this registration technique is assessed using three models: a point target phantom, a cadaveric porcine heart with implanted fiducials, and in-vivo porcine images. Results demonstrate that registration can be achieved with an RMS error of less than 1.5mm, which is within the clinical accuracy requirements of 5mm. US-fluoroscopy registration based on single-perspective pose estimation demonstrates promise as a method for providing guidance to percutaneous aortic valve replacement procedures. Future work will focus on real-time implementation and a visualization system that can be used in the operating room.

Estimating effective dose to pediatric patients undergoing interventional radiology procedures using anthropomorphic phantoms and MOSFET dosimeters.

PubMed

Miksys, Nelson; Gordon, Christopher L; Thomas, Karen; Connolly, Bairbre L

2010-05-01

The purpose of this study was to estimate the effective doses received by pediatric patients during interventional radiology procedures and to present those doses in "look-up tables" standardized according to minute of fluoroscopy and frame of digital subtraction angiography (DSA). Organ doses were measured with metal oxide semiconductor field effect transistor (MOSFET) dosimeters inserted within three anthropomorphic phantoms, representing children at ages 1, 5, and 10 years, at locations corresponding to radiosensitive organs. The phantoms were exposed to mock interventional radiology procedures of the head, chest, and abdomen using posteroanterior and lateral geometries, varying magnification, and fluoroscopy or DSA exposures. Effective doses were calculated from organ doses recorded by the MOSFET dosimeters and are presented in look-up tables according to the different age groups. The largest effective dose burden for fluoroscopy was recorded for posteroanterior and lateral abdominal procedures (0.2-1.1 mSv/min of fluoroscopy), whereas procedures of the head resulted in the lowest effective doses (0.02-0.08 mSv/min of fluoroscopy). DSA exposures of the abdomen imparted higher doses (0.02-0.07 mSv/DSA frame) than did those involving the head and chest. Patient doses during interventional procedures vary significantly depending on the type of procedure. User-friendly look-up tables may provide a helpful tool for health care providers in estimating effective doses for an individual procedure.

Technique for CT Fluoroscopy-Guided Lumbar Medial Branch Blocks and Radiofrequency Ablation.

PubMed

Amrhein, Timothy J; Joshi, Anand B; Kranz, Peter G

2016-09-01

The purpose of this study is to describe the procedure for CT fluoroscopy-guided lumbar medial branch blocks and facet radiofrequency ablation. CT fluoroscopic guidance allows more-precise needle tip positioning and is an alternative method for performing medial branch blocks and facet radiofrequency ablation.

Lower Learning Difficulty and Fluoroscopy Reduction of Transforaminal Percutaneous Endoscopic Lumbar Discectomy with an Accurate Preoperative Location Method.

PubMed

Fan, Guoxin; Gu, Xin; Liu, Yifan; Wu, Xinbo; Zhang, Hailong; Gu, Guangfei; Guan, Xiaofei; He, Shisheng

2016-01-01

Transforaminal percutaneous endoscopic lumbar discectomy (tPELD) poses great challenges for junior surgeons. Beginners often require repeated attempts using fluoroscopy causing more punctures, which may significantly undermine their confidence and increase the radiation exposure to medical staff and patients. Moreover, the impact of an accurate location on the learning curve of tPELD has not been defined. The study aimed to investigate the impact of an accurate preoperative location method on learning difficulty and fluoroscopy time of tPELD. Retrospective evaluation. Patients receiving tPELD by one surgeon with a novel accurate preoperative location method were regarded as Group A, and those receiving tPELD by another surgeon with a conventional fluoroscopy method were regarded as Group B. From January 2012 to August 2014, we retrospectively reviewed the first 80 tPELD cases conducted by 2 junior surgeons. The operation time, fluoroscopy times, preoperative location time, and puncture-channel time were thoroughly analyzed. The operation time of the first 20 patients were 99.75 ± 10.38 minutes in Group A and 115.7 ± 16.46 minutes in Group B, while the operation time of all 80 patients was 88.36 ± 11.56 minutes in Group A and 98.26 ± 14.90 minutes in Group B. Significant differences were detected in operation time between the 2 groups, both for the first 20 patients and total 80 patients (P < 0.05). The fluoroscopy times were 26.78 ± 4.17 in Group A and 33.98 ± 2.69 in Group B (P < 0.001). The preoperative location time was 3.43 ± 0.61 minutes in Group A and 5.59 ± 1.46 minutes in Group B (P < 0.001). The puncture-channel time was 27.20 ± 4.49 minutes in Group A and 34.64 ± 8.35 minutes in Group B (P < 0.001). There was a moderate correlation between preoperative location time and puncture-channel time (r = 0.408, P < 0.001), and a moderate correlation between preoperative location time and fluoroscopy times (r = 0.441, P < 0.001). Mild correlations were also observed between preoperative location time and operation time (r = 0.270, P = 0.001). There were no significant differences in preoperative back visual analogue scale (VAS) score, postoperative back VAS, preoperative leg VAS, postoperative leg VAS, preoperative Japanese Orthopaedic Association (JOA) score, postoperative JOA, preoperative Oswestry disability score (ODI), or postoperative ODI (P > 0.05). However, significant differences were all detected between preoperative abovementioned scores and postoperative scores (P < 0.05). Moreover, there was no significant differences in Macnab satisfaction between the 2 groups (P = 0.179). There were 2 patients with recurrence in Group A and 3 patients in Group B. Twelve patients with postoperative disc remnants were identified in Group A and 9 patients in Group B. No significant difference was identified between the 2 groups (P = 0.718). The preoperative lumbar location method is just a tiny step in tPELD, junior surgeons still need to focus on their subjective feelings during punctures and accumulating their experience in endoscopic discectomy. The accurate preoperative location method lowered the learning difficulty and reduced the fluoroscopy time of tPELD, which was also associated with lower preoperative location time and puncture-channel time. Key words: Learning difficulty, fluoroscopy reduction, transforamimal percutaneous endoscopic lumbar discectomy, preoperative locationLearning difficulty, fluoroscopy reduction, transforamimal percutaneous endoscopic lumbar discectomy, preoperative location.

The evaluation of radiologic methods for access guidance in percutaneous nephrolithotomy: a systematic review of the literature.

PubMed

Breda, Alberto; Territo, Angelo; Scoffone, Cesare; Seitz, Christian; Knoll, Thomas; Herrmann, Thomas; Brehmer, Mariannhe; Osther, Palle J S; Liatsikos, Evangelos

2017-11-12

Percutaneous nephrolithotomy (PNL) is the treatment of choice for larger and complex renal calculi. First step in performing PNL is to obtain access to the renal cavity using either fluoroscopy or ultrasound (US) guidance or a combination of both. Which guiding method to choose is controversial? A systematic review of the literature was performed comparing image guidance modalities for obtaining access in PNL. Evidence acquisition and synthesis: A PubMed, Scopus and Cochrane search for peer-reviewed studies was performed using the keywords "ultrasound" AND "fluoroscopy" AND "Percutaneous nephrolithotomy". Eligible articles were reviewed according to PRISMA criteria. Two hundred and forty records were identified using the keywords. Of these twelve studies were considered relevant. US guidance seems to be associated with a slightly lower complication rate, which may be related to fewer puncture attempts needed for obtaining access and to better peri-renal organ visualization. On the other hand, US-guidance alone needs the adjunct of fluoroscopy in a significant number of cases for achieving access. Stone free rate (SFR) was comparable between groups. Using US for renal access unequivocally reduces radiation exposure. Current evidence indicates that both fluoroscopy and US guidance may be successfully used for obtaining percutaneous renal access. Combining the image-guiding modalities - US and fluoroscopy - seems to increase outcome in PNL both with regard to success in achieving access and reducing complications. Furthermore, including US in the access strategy of PNL reduces radiation exposure to surgeon and staff as well as patients.

Semi-automated intra-operative fluoroscopy guidance for osteotomy and external-fixator.

PubMed

Lin, Hong; Samchukov, Mikhail L; Birch, John G; Cherkashin, Alexander

2006-01-01

This paper outlines a semi-automated intra-operative fluoroscopy guidance and monitoring approach for osteotomy and external-fixator application in orthopedic surgery. Intra-operative Guidance module is one component of the "LegPerfect Suite" developed for assisting the surgical correction of lower extremity angular deformity. The Intra-operative Guidance module utilizes information from the preoperative surgical planning module as a guideline to overlay (register) its bone outline semi-automatically with the bone edge from the real-time fluoroscopic C-Arm X-Ray image in the operating room. In the registration process, scaling factor is obtained automatically through matching a fiducial template in the fluoroscopic image and a marker in the module. A triangle metal plate, placed on the operating table is used as fiducial template. The area of template image within the viewing area of the fluoroscopy machine is obtained by the image processing techniques such as edge detection and Hough transformation to extract the template from other objects in the fluoroscopy image. The area of fiducial template from fluoroscopic image is then compared with the area of the marker from the planning so as to obtain the scaling factor. After the scaling factor is obtained, the user can use simple operations by mouse to shift and rotate the preoperative planning to overlay the bone outline from planning with the bone edge from fluoroscopy image. In this way osteotomy levels and external fixator positioning on the limb can guided by the computerized preoperative plan.

A Dynamic Image Quality Evaluation of Videofluoroscopy Images: Considerations for Telepractice Applications.

PubMed

Burns, Clare L; Keir, Benjamin; Ward, Elizabeth C; Hill, Anne J; Farrell, Anna; Phillips, Nick; Porter, Linda

2015-08-01

High-quality fluoroscopy images are required for accurate interpretation of videofluoroscopic swallow studies (VFSS) by speech pathologists and radiologists. Consequently, integral to developing any system to conduct VFSS remotely via telepractice is ensuring that the quality of the VFSS images transferred via the telepractice system is optimized. This study evaluates the extent of change observed in image quality when videofluoroscopic images are transmitted from a digital fluoroscopy system to (a) current clinical equipment (KayPentax Digital Swallowing Workstation, and b) four different telepractice system configurations. The telepractice system configurations consisted of either a local C20 or C60 Cisco TelePresence System (codec unit) connected to the digital fluoroscopy system and linked to a second remote C20 or C60 Cisco TelePresence System via a network running at speeds of either 2, 4 or 6 megabits per second (Mbit/s). Image quality was tested using the NEMA XR 21 Phantom, and results demonstrated some loss in spatial resolution, low contrast detectability and temporal resolution for all transferred images when compared to the fluoroscopy source. When using higher capacity codec units and/or the highest bandwidths to support data transmission, image quality transmitted through the telepractice system was found to be comparable if not better than the current clinical system. This study confirms that telepractice systems can be designed to support fluoroscopy image transfer and highlights important considerations when developing telepractice systems for VFSS analysis to ensure high-quality radiological image reproduction.

Accuracy in identifying the elbow rotation axis on simulated fluoroscopic images using a new anatomical landmark.

PubMed

Wiggers, J K; Snijders, R M; Dobbe, J G G; Streekstra, G J; den Hartog, D; Schep, N W L

2017-11-01

External fixation of the elbow requires identification of the elbow rotation axis, but the accuracy of traditional landmarks (capitellum and trochlea) on fluoroscopy is limited. The relative distance (RD) of the humerus may be helpful as additional landmark. The first aim of this study was to determine the optimal RD that corresponds to an on-axis lateral image of the elbow. The second aim was to assess whether the use of the optimal RD improves the surgical accuracy to identify the elbow rotation axis on fluoroscopy. CT scans of elbows from five volunteers were used to simulate fluoroscopy; the actual rotation axis was calculated with CT-based flexion-extension analysis. First, three observers measured the optimal RD on simulated fluoroscopy. The RD is defined as the distance between the dorsal part of the humerus and the projection of the posteromedial cortex of the distal humerus, divided by the anteroposterior diameter of the humerus. Second, eight trauma surgeons assessed the elbow rotation axis on simulated fluoroscopy. In a preteaching session, surgeons used traditional landmarks. The surgeons were then instructed how to use the optimal RD as additional landmark in a postteaching session. The deviation from the actual rotation axis was expressed as rotational and translational error (±SD). Measurement of the RD was robust and easily reproducible; the optimal RD was 45%. The surgeons identified the elbow rotation axis with a mean rotational error decreasing from 7.6° ± 3.4° to 6.7° ± 3.3° after teaching how to use the RD. The mean translational error decreased from 4.2 ± 2.0 to 3.7 ± 2.0 mm after teaching. The humeral RD as additional landmark yielded small but relevant improvements. Although fluoroscopy-based external fixator alignment to the elbow remains prone to error, it is recommended to use the RD as additional landmark.

Flexible robotics with electromagnetic tracking improves safety and efficiency during in vitro endovascular navigation.

PubMed

Schwein, Adeline; Kramer, Ben; Chinnadurai, Ponraj; Walker, Sean; O'Malley, Marcia; Lumsden, Alan; Bismuth, Jean

2017-02-01

One limitation of the use of robotic catheters is the lack of real-time three-dimensional (3D) localization and position updating: they are still navigated based on two-dimensional (2D) X-ray fluoroscopic projection images. Our goal was to evaluate whether incorporating an electromagnetic (EM) sensor on a robotic catheter tip could improve endovascular navigation. Six users were tasked to navigate using a robotic catheter with incorporated EM sensors in an aortic aneurysm phantom. All users cannulated two anatomic targets (left renal artery and posterior "gate") using four visualization modes: (1) standard fluoroscopy mode (control), (2) 2D fluoroscopy mode showing real-time virtual catheter orientation from EM tracking, (3) 3D model of the phantom with anteroposterior and endoluminal view, and (4) 3D model with anteroposterior and lateral view. Standard X-ray fluoroscopy was always available. Cannulation and fluoroscopy times were noted for every mode. 3D positions of the EM tip sensor were recorded at 4 Hz to establish kinematic metrics. The EM sensor-incorporated catheter navigated as expected according to all users. The success rate for cannulation was 100%. For the posterior gate target, mean cannulation times in minutes:seconds were 8:12, 4:19, 4:29, and 3:09, respectively, for modes 1, 2, 3 and 4 (P = .013), and mean fluoroscopy times were 274, 20, 29, and 2 seconds, respectively (P = .001). 3D path lengths, spectral arc length, root mean dimensionless jerk, and number of submovements were significantly improved when EM tracking was used (P < .05), showing higher quality of catheter movement with EM navigation. The EM tracked robotic catheter allowed better real-time 3D orientation, facilitating navigation, with a reduction in cannulation and fluoroscopy times and improvement of motion consistency and efficiency. Copyright © 2016 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

Right heart catheterization using metallic guidewires and low SAR cardiovascular magnetic resonance fluoroscopy at 1.5 Tesla: first in human experience.

PubMed

Campbell-Washburn, Adrienne E; Rogers, Toby; Stine, Annette M; Khan, Jaffar M; Ramasawmy, Rajiv; Schenke, William H; McGuirt, Delaney R; Mazal, Jonathan R; Grant, Laurie P; Grant, Elena K; Herzka, Daniel A; Lederman, Robert J

2018-06-21

Cardiovascular magnetic resonance (CMR) fluoroscopy allows for simultaneous measurement of cardiac function, flow and chamber pressure during diagnostic heart catheterization. To date, commercial metallic guidewires were considered contraindicated during CMR fluoroscopy due to concerns over radiofrequency (RF)-induced heating. The inability to use metallic guidewires hampers catheter navigation in patients with challenging anatomy. Here we use low specific absorption rate (SAR) imaging from gradient echo spiral acquisitions and a commercial nitinol guidewire for CMR fluoroscopy right heart catheterization in patients. The low-SAR imaging protocol used a reduced flip angle gradient echo acquisition (10° vs 45°) and a longer repetition time (TR) spiral readout (10 ms vs 2.98 ms). Temperature was measured in vitro in the ASTM 2182 gel phantom and post-mortem animal experiments to ensure freedom from heating with the selected guidewire (150 cm × 0.035″ angled-tip nitinol Terumo Glidewire). Seven patients underwent CMR fluoroscopy catheterization. Time to enter each chamber (superior vena cava, main pulmonary artery, and each branch pulmonary artery) was recorded and device visibility and confidence in catheter and guidewire position were scored on a Likert-type scale. Negligible heating (< 0.07°C) was observed under all in vitro conditions using this guidewire and imaging approach. In patients, chamber entry was successful in 100% of attempts with a guidewire compared to 94% without a guidewire, with failures to reach the branch pulmonary arteries. Time-to-enter each chamber was similar (p=NS) for  the two approaches. The guidewire imparted useful catheter shaft conspicuity and enabled interactive modification of catheter shaft stiffness, however, the guidewire tip visibility was poor. Under specific conditions, trained operators can apply low-SAR imaging and using a specific fully-insulated metallic nitinol guidewire (150 cm × 0.035" Terumo Glidewire) to augment clinical CMR fluoroscopy right heart catheterization. Clinicaltrials.gov NCT03152773 , registered May 15, 2017.

Learning curve in transradial cardiac catheterization: procedure-related parameters stratified by operators' transradial volume.

PubMed

Kasasbeh, Ehab S; Parvez, Babar; Huang, Robert L; Hasselblad, Michele Marie; Glazer, Mark D; Salloum, Joseph G; Cleator, John H; Zhao, David X

2012-11-01

To determine whether radial artery access is associated with a reduction in fluoroscopy time, procedure time, and other procedural variables over a 27-month period during which the radial artery approach was incorporated in a single academic Medical Center. Although previous studies have demonstrated a relationship between increased volume and decreased procedural time, no studies have looked at the integration of radial access over time. Data were collected from consecutive patients who presented to the Vanderbilt University Medical Center cardiac catheterization laboratory from January 1, 2009 to April 1, 2011. Patients who underwent radial access diagnostic catheterization with and without percutaneous coronary intervention were included in this study. A total of 1112 diagnostic cardiac catheterizations through the radial access site were analyzed. High-volume, intermediate-volume, and low-volume operators were grouped based on the percentage of procedures performed through a radial approach. From 2009 to 2011, there was a significant decrease in fluoroscopy time in all operator groups for diagnostic catheterization (P=.035). The high-volume operator group had 1.88 and 3.66 minute reductions in fluoroscopy time compared to the intermediate- and low-volume operator groups, respectively (both P<.001). Likewise, the intermediate-volume operator group had a 1.77 minute improvement compared to the low-volume operator group, but this did not reach statistical significance (P=.102). The improvement in fluoroscopy time and other procedure-related parameters was seen after approximately 25 cases with further improvement after 75 cases. The incorporation of the radial access approach in the cardiac catheterization laboratory led to a decrease in fluoroscopy time for each operator and operator group over the last 3 years. Our data demonstrated that higher-volume radial operators have better procedure, room, and fluoroscopy times when compared to intermediate- and low-volume operators. However, lower-volume operators have a reduction in procedure-related parameters with increased radial cases. Number of procedures needed to become sufficient was demonstrated in the current study.

Electromagnetic tracking of flexible robotic catheters enables "assisted navigation" and brings automation to endovascular navigation in an in vitro study.

PubMed

Schwein, Adeline; Kramer, Benjamin; Chinnadurai, Ponraj; Virmani, Neha; Walker, Sean; O'Malley, Marcia; Lumsden, Alan B; Bismuth, Jean

2018-04-01

Combining three-dimensional (3D) catheter control with electromagnetic (EM) tracking-based navigation significantly reduced fluoroscopy time and improved robotic catheter movement quality in a previous in vitro pilot study. The aim of this study was to expound on previous results and to expand the value of EM tracking with a novel feature, assistednavigation, allowing automatic catheter orientation and semiautomatic vessel cannulation. Eighteen users navigated a robotic catheter in an aortic aneurysm phantom using an EM guidewire and a modified 9F robotic catheter with EM sensors at the tip of both leader and sheath. All users cannulated two targets, the left renal artery and posterior gate, using four visualization modes: (1) Standard fluoroscopy (control). (2) 2D biplane fluoroscopy showing real-time virtual catheter localization and orientation from EM tracking. (3) 2D biplane fluoroscopy with novel EM assisted navigation allowing the user to define the target vessel. The robotic catheter orients itself automatically toward the target; the user then only needs to advance the guidewire following this predefined optimized path to catheterize the vessel. Then, while advancing the catheter over the wire, the assisted navigation automatically modifies catheter bending and rotation in order to ensure smooth progression, avoiding loss of wire access. (4) Virtual 3D representation of the phantom showing real-time virtual catheter localization and orientation. Standard fluoroscopy was always available; cannulation and fluoroscopy times were noted for every mode and target cannulation. Quality of catheter movement was assessed by measuring the number of submovements of the catheter using the 3D coordinates of the EM sensors. A t-test was used to compare the standard fluoroscopy mode against EM tracking modes. EM tracking significantly reduced the mean fluoroscopy time (P < .001) and the number of submovements (P < .02) for both cannulation tasks. For the posterior gate, mean cannulation time was also significantly reduced when using EM tracking (P < .001). The use of novel EM assisted navigation feature (mode 3) showed further reduced cannulation time for the posterior gate (P = .002) and improved quality of catheter movement for the left renal artery cannulation (P = .021). These results confirmed the findings of a prior study that highlighted the value of combining 3D robotic catheter control and 3D navigation to improve safety and efficiency of endovascular procedures. The novel EM assisted navigation feature augments the robotic master/slave concept with automated catheter orientation toward the target and shows promising results in reducing procedure time and improving catheter motion quality. Copyright © 2017 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

Oral versus intravenous premedication for small bowel biopsy in children: effect on procedure and fluoroscopy times.

PubMed

Stenhammar, L; Wärngård, O; Lewander, P; Nordvall, M

1993-01-01

Oral alimemazine and cisapride, or diazepam and cisapride, or iv midazolam and metoclopramide were given as premedication for small bowel biopsy to three groups of children from a total population of 185 individuals. The biopsy procedures were performed under intermittent fluoroscopy and times for both were recorded. The median biopsy procedure time was significantly shorter in children given iv midazolam and metoclopramide (6 min) compared to those given oral premedication (10 min) (p < 0.001). The median fluoroscopy time was very short in all groups, ranging between 3 and 6 s. It is concluded that iv premedication is superior to oral premedication for small bowel biopsy in children because more effective sedation is obtained.

CT Fluoroscopy-Guided Transsacral Intervertebral Drainage for Pyogenic Spondylodiscitis at the Lumbosacral Junction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matsumoto, Tomohiro, E-mail: t-matsu@tokai-u.jp; Mine, Takahiko, E-mail: mine@tsc.u-tokai.ac.jp; Hayashi, Toshihiko, E-mail: t.hayashi@tokai.ac.jp

PurposeTo retrospectively describe the feasibility and efficacy of CT fluoroscopy-guided transsacral intervertebral drainage for pyogenic spondylodiscitis at the lumbosacral junction with a combination of two interventional radiological techniques—CT-guided bone biopsy and abscess drainage.Materials and methodsThree patients with pyogenic spondylodiscitis at the lumbosacral junction were enrolled in this study between July 2013 and December 2015. The procedure of CT fluoroscopy-guided transsacral intervertebral drainage for pyogenic spondylodiscitis at the lumbosacral junction was as follows: the sacrum at S1 pedicle was penetrated with an 11-gauge (G) bone biopsy needle to create a path for an 8-French (F) pigtail drainage catheter. The bone biopsymore » needle was withdrawn, and an 18-G needle was inserted into the intervertebral space of the lumbosacral junction. Then, a 0.038-inch guidewire was inserted into the intervertebral space. Finally, the 8-F pigtail drainage catheter was inserted over the guidewire until its tip reached the intervertebral space. All patients received six-week antibiotics treatment.ResultsSuccessful placement of the drainage catheter was achieved for each patient without procedural complications. The duration of drainage was 17–33 days. For two patients, specific organisms were isolated; thus, definitive medical therapy was possible. All patients responded well to the treatment.ConclusionsCT fluoroscopy-guided transsacral intervertebral drainage for pyogenic spondylodiscitis at the lumbosacral junction is feasible and can be effective with a combination of two interventional techniques—CT fluoroscopy-guided bone biopsy and abscess drainage.« less

[New ultrasound navigational system in extracorporeal lithotripsy: decreased fluoroscopy and radiation].

PubMed

Abid, N; Ravier, E; Codas, R; Crouzet, S; Martin, X

2013-09-01

Extracorporeal shock wave lithotripsy is the most common method of treatment for kidney stones. Both fluoroscopy and ultrasound imaging can be used to locate stones, but fluoroscopy is more frequently employed. Evaluation of a new stereotaxic navigational system: the stone was located using an ultrasound probe, and its 3D location was saved. The table automatically moved to position the stone at the focal point. A real-time follow-up was possible during treatment. Our objective was to demonstrate a decrease in the use of fluoroscopy to locate kidney stones for extracorporeal shock wave lithotripsy through the use of a 3D ultrasound stone locking system. Prospective analysis of the case records of the 20 patients preceding and the 20 patients succeeding the arrival of the ultrasound stone locking system Visio-Track (EDAP-TMS). We used a Student test to compare age, BMI, kidney stone size, number of shock waves and administered energy. Patient characteristics were comparable. The average age was 55 years old and the average kidney stone size was 10.7 mm. Radiation duration was 174.8 seconds in the group without Visio-Track versus 57.1 seconds in the group with it (P<0.0001). A similar result was observed for radiation doses: 5197.25 mGy x cm2 for the group without versus 1987.6 mGy x cm2 for the group with Visio-Track (P=0.0033). The stone locking system Visio-Track reduced fluoroscopy in our first group of patients, which decreased the patient's individual absorbed irradiation dose. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Laser Guidance in C-Arm Cone-Beam CT-Guided Radiofrequency Ablation of Osteoid Osteoma Reduces Fluoroscopy Time

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kroes, Maarten W., E-mail: Maarten.Kroes@radboudumc.nl; Busser, Wendy M. H.; Hoogeveen, Yvonne L.

PurposeTo assess whether laser guidance can reduce fluoroscopy and procedure time of cone-beam computed tomography (CBCT)-guided radiofrequency (RF) ablations of osteoid osteoma compared to freehand CBCT guidance.Materials and Methods32 RF ablations were retrospectively analyzed, 17 laser-guided and 15 procedures using the freehand technique. Subgroup selection of 18 ablations in the hip–pelvic region with a similar degree of difficulty was used for a direct comparison. Data are presented as median (ranges).ResultsComparison of all 32 ablations resulted in fluoroscopy times of 365 s (193–878 s) for freehand and 186 s (75–587 s) for laser-guided procedures (p = 0.004). Corresponding procedure times were 56 min (35–97 min) and 52 min (30–85 min) (p = 0.355).more » The subgroup showed comparable target sizes, needle path lengths, and number of scans between groups. Fluoroscopy times were lower for laser-guided procedures, 215 s (75–413 s), compared to 384 s (193–878 s) for freehand (p = 0.012). Procedure times were comparable between groups, 51 min (30–72 min) for laser guidance and 58 min (35–79 min) for freehand (p = 0.172).ConclusionAdding laser guidance to CBCT-guided osteoid osteoma RF ablations significantly reduced fluoroscopy time without increasing procedure time.Level of EvidenceLevel 4, case series.« less

CT fluoroscopy-guided renal tumour cutting needle biopsy: retrospective evaluation of diagnostic yield, safety, and risk factors for diagnostic failure.

PubMed

Iguchi, Toshihiro; Hiraki, Takao; Matsui, Yusuke; Fujiwara, Hiroyasu; Sakurai, Jun; Masaoka, Yoshihisa; Gobara, Hideo; Kanazawa, Susumu

2018-01-01

To evaluate retrospectively the diagnostic yield, safety, and risk factors for diagnostic failure of computed tomography (CT) fluoroscopy-guided renal tumour biopsy. Biopsies were performed for 208 tumours (mean diameter 2.3 cm; median diameter 2.1 cm; range 0.9-8.5 cm) in 199 patients. One hundred and ninety-nine tumours were ≤4 cm. All 208 initial procedures were divided into diagnostic success and failure groups. Multiple variables related to the patients, lesions, and procedures were assessed to determine the risk factors for diagnostic failure. After performing 208 initial and nine repeat biopsies, 180 malignancies and 15 benign tumours were pathologically diagnosed, whereas 13 were not diagnosed. In 117 procedures, 118 Grade I and one Grade IIIa adverse events (AEs) occurred. Neither Grade ≥IIIb AEs nor tumour seeding were observed within a median follow-up period of 13.7 months. Logistic regression analysis revealed only small tumour size (≤1.5 cm; odds ratio 3.750; 95% confidence interval 1.362-10.326; P = 0.011) to be a significant risk factor for diagnostic failure. CT fluoroscopy-guided renal tumour biopsy is a safe procedure with a high diagnostic yield. A small tumour size (≤1.5 cm) is a significant risk factor for diagnostic failure. • CT fluoroscopy-guided renal tumour biopsy has a high diagnostic yield. • CT fluoroscopy-guided renal tumour biopsy is safe. • Small tumour size (≤1.5 cm) is a risk factor for diagnostic failure.

[Fluoroscopy dose reduction of computed tomography guided chest interventional radiology using real-time iterative reconstruction].

PubMed

Hasegawa, Hiroaki; Mihara, Yoshiyuki; Ino, Kenji; Sato, Jiro

2014-11-01

The purpose of this study was to evaluate the radiation dose reduction to patients and radiologists in computed tomography (CT) guided examinations for the thoracic region using CT fluoroscopy. Image quality evaluation of the real-time filtered back-projection (RT-FBP) images and the real-time adaptive iterative dose reduction (RT-AIDR) images was carried out on noise and artifacts that were considered to affect the CT fluoroscopy. The image standard deviation was improved in the fluoroscopy setting with less than 30 mA on 120 kV. With regard to the evaluation of artifact visibility and the amount generated by the needle attached to the chest phantom, there was no significant difference between the RT-FBP images with 120 kV, 20 mA and the RT-AIDR images with low-dose conditions (greater than 80 kV, 30 mA and less than 120 kV, 20 mA). The results suggest that it is possible to reduce the radiation dose by approximately 34% at the maximum using RT-AIDR while maintaining image quality equivalent to the RT-FBP images with 120 V, 20 mA.

[Routine fluoroscopic investigations after primary bariatric surgery].

PubMed

Gärtner, D; Ernst, A; Fedtke, K; Jenkner, J; Schöttler, A; Reimer, P; Blüher, M; Schön, M R

2016-03-01

Staple line and anastomotic leakages are life-threatening complications after bariatric surgery. Upper gastrointestinal (GI) tract X-ray examination with oral administration of a water-soluble contrast agent can be used to detect leaks. The aim of this study was to evaluate the impact of routine upper GI tract fluoroscopy after primary bariatric surgery. Between January 2009 and December 2014 a total of 658 bariatric interventions were carried out of which 442 were primary bariatric operations. Included in this single center study were 307 sleeve gastrectomies and 135 Roux-en-Y gastric bypasses. Up to December 2012 upper GI tract fluoroscopy was performed routinely between the first and third postoperative days and the detection of leakages was evaluated. In the investigation period 8 leakages (2.6 %) after sleeve gastrectomy, 1 anastomotic leakage in gastrojejunostomy and 1 in jejunojejunostomy after Roux-en-Y gastric bypass occurred. All patients developed clinical symptoms, such as abdominal pain, tachycardia or fever. In one case the leakage was detected by upper GI fluoroscopy and in nine cases radiological findings were unremarkable. No leakages were detected in asymptomatic patients. Routine upper GI fluoroscopy is not recommended for uneventful postoperative courses after primary bariatric surgery.

Rapid fusion of 2D X-ray fluoroscopy with 3D multislice CT for image-guided electrophysiology procedures

NASA Astrophysics Data System (ADS)

Zagorchev, Lyubomir; Manzke, Robert; Cury, Ricardo; Reddy, Vivek Y.; Chan, Raymond C.

2007-03-01

Interventional cardiac electrophysiology (EP) procedures are typically performed under X-ray fluoroscopy for visualizing catheters and EP devices relative to other highly-attenuating structures such as the thoracic spine and ribs. These projections do not however contain information about soft-tissue anatomy and there is a recognized need for fusion of conventional fluoroscopy with pre-operatively acquired cardiac multislice computed tomography (MSCT) volumes. Rapid 2D-3D integration in this application would allow for real-time visualization of all catheters present within the thorax in relation to the cardiovascular anatomy visible in MSCT. We present a method for rapid fusion of 2D X-ray fluoroscopy with 3DMSCT that can facilitate EP mapping and interventional procedures by reducing the need for intra-operative contrast injections to visualize heart chambers and specialized systems to track catheters within the cardiovascular anatomy. We use hardware-accelerated ray-casting to compute digitally reconstructed radiographs (DRRs) from the MSCT volume and iteratively optimize the rigid-body pose of the volumetric data to maximize the similarity between the MSCT-derived DRR and the intra-operative X-ray projection data.

[Evaluation of Radiation Dose during Stent-graft Treatment Using a Hybrid Operating Room System].

PubMed

Haga, Yoshihiro; Chida, Kouichi; Kaga, Yuji; Saitou, Kazuhisa; Arai, Takeshi; Suzuki, Shinichi; Iwaya, Yoshimi; Kumasaka, Eriko; Kataoka, Nozomi; Satou, Naoto; Abe, Mitsuya

2015-12-01

In recent years, aortic aneurysm treatment with stent graft grafting in the X-ray fluoroscopy is increasing. This is an endovascular therapy, because it is a treatment which includes the risk of radiation damage, having to deal with radiation damage, to know in advance is important. In this study, in order to grasp the trend of exposure stent graft implantation in a hybrid operating room (OR) system, focusing on clinical data (entrance skin dose and fluoroscopy time), was to count the total. In TEVAR and EVAR, fluoroscopy time became 13.40 ± 7.27 minutes, 23.67 ± 11.76 minutes, ESD became 0.87 ± 0.41 mGy, 1.11 ± 0.57 mGy. (fluoroscopy time of EVAR was 2.0 times than TEVAR. DAP of EVAR was 1.2 times than TEVAR.) When using the device, adapted lesions and usage are different. This means that care changes in exposure-related factors. In this study, exposure trends of the stent graft implantation was able to grasp. It can be a helpful way to reduce/optimize the radiation dose in a hybrid OR system.

How well can step-off and gap distances be reduced when treating intra-articular distal radius fractures with fragment specific fixation when using fluoroscopy.

PubMed

Thiart, M; Ikram, A; Lamberts, R P

2016-12-01

Although fragment specific fixation has proved to be an effective treatment regime, it has not been established how successfully this treatment could be performed using fluoroscopy and what the added value of arthroscopy could be. Establish gap and step-off distances after in intra-articular distal radius fractures that have been treated with fragment specific fixation while using fluoroscopy. Forty-four patients with an intra-articular distal radius fracture were treated with fragment specific fixation while using fluoroscopy. After the treatment of the intra-articular distal radius fracture with fragment specific fixation and the use of fluoroscopy, but before the completion of the surgical intervention, all gap, and step-off distances were determined by using arthroscopy. In addition, the joint was checked for any other wrist pathologies. Arthroscopy after the surgical intervention showed that in 37 patients no gap distances could be detected, while in six patients a gap distance of≤2mm was found and in one patient, a gap distance of 3mm. Similarly, arthroscopy revealed no step-off distances in 33 patients, while in 11 patients a step-off distance of≤2mm was found. Although additional wrist pathologies were found in 48% of our population, only one patient needed surgical intervention. Three months after the surgical intervention wrist flexion was 41±10°, wrist extension 51±17°, ulnar deviation 19±10°, radial deviation 32±12° while patients could pronate and supinate their wrist to 85±5° and 74±20°, respectively. Intra-articular distal radius fractures can be treated successfully with fragment specific fixation and the use of fluoroscopy. As almost all gap and step-off distances could be reduced to an acceptable level, the scope for arthroscopy to further improve this treatment regime is limited. The functional outcome scores that were found 3 months after the surgical intervention were similar to what has been reported in other studies using different treatment option. These findings suggest that fragment specific fixation is a good alternative for treating intra-articular distal radius fractures. As in most cases, only fluoroscopy is needed for fragment specific fixation, this treatment technique is a good treatment option for resource-limited hospitals, setting who do not have access to arthroscopy. III, case-control study. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Biplane interventional pediatric system with cone‐beam CT: dose and image quality characterization for the default protocols

PubMed Central

Vañó, Eliseo; Alejo, Luis; Ubeda, Carlos; Gutiérrez‐Larraya, Federico; Garayoa, Julia

2016-01-01

The aim of this study was to assess image quality and radiation dose of a biplane angiographic system with cone‐beam CT (CBCT) capability tuned for pediatric cardiac procedures. The results of this study can be used to explore dose reduction techniques. For pulsed fluoroscopy and cine modes, polymethyl methacrylate phantoms of various thicknesses and a Leeds TOR 18‐FG test object were employed. Various fields of view (FOV) were selected. For CBCT, the study employed head and body dose phantoms, Catphan 504, and an anthropomorphic cardiology phantom. The study also compared two 3D rotational angiography protocols. The entrance surface air kerma per frame increases by a factor of 3–12 when comparing cine and fluoroscopy frames. The biggest difference in the signal‐to‐noise ratio between fluoroscopy and cine modes occurs at FOV 32 cm because fluoroscopy is acquired at a 1440×1440 pixel matrix size and in unbinned mode, whereas cine is acquired at 720×720 pixels and in binned mode. The high‐contrast spatial resolution of cine is better than that of fluoroscopy, except for FOV 32 cm, because fluoroscopy mode with 32 cm FOV is unbinned. Acquiring CBCT series with a 16 cm head phantom using the standard dose protocol results in a threefold dose increase compared with the low‐dose protocol. Although the amount of noise present in the images acquired with the low‐dose protocol is much higher than that obtained with the standard mode, the images present better spatial resolution. A 1 mm diameter rod with 250 Hounsfield units can be distinguished in reconstructed images with an 8 mm slice width. Pediatric‐specific protocols provide lower doses while maintaining sufficient image quality. The system offers a novel 3D imaging mode. The acquisition of CBCT images results in increased doses administered to the patients, but also provides further diagnostic information contained in the volumetric images. The assessed CBCT protocols provide images that are noisy, but with very good spatial resolution. PACS number(s): 87.59.‐e, 87.59.‐C, 87.59.‐cf, 87.59.Dj, 87.57. uq PMID:27455474

Automatic Localization of Vertebral Levels in X-Ray Fluoroscopy Using 3D-2D Registration: A Tool to Reduce Wrong-Site Surgery

PubMed Central

Otake, Y.; Schafer, S.; Stayman, J. W.; Zbijewski, W.; Kleinszig, G.; Graumann, R.; Khanna, A. J.; Siewerdsen, J. H.

2012-01-01

Surgical targeting of the incorrect vertebral level (“wrong-level” surgery) is among the more common wrong-site surgical errors, attributed primarily to a lack of uniquely identifiable radiographic landmarks in the mid-thoracic spine. Conventional localization method involves manual counting of vertebral bodies under fluoroscopy, is prone to human error, and carries additional time and dose. We propose an image registration and visualization system (referred to as LevelCheck), for decision support in spine surgery by automatically labeling vertebral levels in fluoroscopy using a GPU-accelerated, intensity-based 3D-2D (viz., CT-to-fluoroscopy) registration. A gradient information (GI) similarity metric and CMA-ES optimizer were chosen due to their robustness and inherent suitability for parallelization. Simulation studies involved 10 patient CT datasets from which 50,000 simulated fluoroscopic images were generated from C-arm poses selected to approximate C-arm operator and positioning variability. Physical experiments used an anthropomorphic chest phantom imaged under real fluoroscopy. The registration accuracy was evaluated as the mean projection distance (mPD) between the estimated and true center of vertebral levels. Trials were defined as successful if the estimated position was within the projection of the vertebral body (viz., mPD < 5mm). Simulation studies showed a success rate of 99.998% (1 failure in 50,000 trials) and computation time of 4.7 sec on a midrange GPU. Analysis of failure modes identified cases of false local optima in the search space arising from longitudinal periodicity in vertebral structures. Physical experiments demonstrated robustness of the algorithm against quantum noise and x-ray scatter. The ability to automatically localize target anatomy in fluoroscopy in near-real-time could be valuable in reducing the occurrence of wrong-site surgery while helping to reduce radiation exposure. The method is applicable beyond the specific case of vertebral labeling, since any structure defined in pre-operative (or intra-operative) CT or cone-beam CT can be automatically registered to the fluoroscopic scene. PMID:22864366

SU-E-I-26: Estimation of Micro-Angiographic Fluoroscope (MAF) Gain Settings for Digital Subtraction Angiography (DSA) Based on the Fluoroscopic Exposure.

PubMed

Ionita, C; Loughran, B; Nagesh, S Setlur; Jain, A; Bednarek, D; Rudin, S

2012-06-01

The MAF is a new high-resolution detector which is being clinically evaluated in neuro-vascular procedures. The detector contains a large-dynamic-range, high-sensitivity light image intensifier with variable gain. Since the MAF is a research prototype only partially integrated with the clinical system, x-ray technique parameters must be set manually. To improve workflow we developed an automatic method to estimate and set the proper LII voltage (MAF gain) for DSA acquisition based on the fluoroscopic parameters. The detector entrance exposure (XD) can be written as the x-ray tube output exposure (Xo) times an object attenuation factor and an inverse-square correction. If the object attenuation, scatter and distances are unchanged and the effect of x-ray kVp changes are neglected, then the DSA XD can be expressed as the ratio of Xo(DSA)/Xo(Fluoroscopy) multiplied with XD(fluoroscopy). We measured Xo for fluoroscopy and DSA for mAs and kVp ranges appropriate to neuro- vascular interventions and fit the data with a 2D function. To estimate the XD(Fluoroscopy) we derived a curve of XD versus LII-voltage for a mid- dynamic-range average pixel gray-level. Since the MAF system during clinical fluoroscopy automatically adjusts the LII voltage until the desired gray-level value is achieved, by reading that voltage we can estimate the XD(Fluoroscopy). Using the 2D-fit function, Xo(DSA) is automatically calculated for the kVp and mA values set and XD(DSA) can be estimated using the relation above. Using the inverse LII calibration curve, the proper LII-voltage can be determined for the desired average gray-level. The algorithm was implemented and evaluated in thirty-two in-vivo DSA runs on rabbits. The proper LII voltage was selected in all cases with no failures. Using the fluoroscopic LII gain setting to determine the appropriate DSA setting can greatly improve the workflow in clinical evaluations of the MAF. NIH Grants R01-EB008425, R01-EB002873 and an equipment grant from Toshiba Medical Systems Corp. © 2012 American Association of Physicists in Medicine.

Biplane interventional pediatric system with cone-beam CT: dose and image quality characterization for the default protocols.

PubMed

Corredoira, Eva; Vañó, Eliseo; Alejo, Luis; Ubeda, Carlos; Gutiérrez-Larraya, Federico; Garayoa, Julia

2016-07-08

The aim of this study was to assess image quality and radiation dose of a biplane angiographic system with cone-beam CT (CBCT) capability tuned for pediatric cardiac procedures. The results of this study can be used to explore dose reduction techniques. For pulsed fluoroscopy and cine modes, polymethyl methacrylate phantoms of various thicknesses and a Leeds TOR 18-FG test object were employed. Various fields of view (FOV) were selected. For CBCT, the study employed head and body dose phantoms, Catphan 504, and an anthropomorphic cardiology phantom. The study also compared two 3D rotational angiography protocols. The entrance surface air kerma per frame increases by a factor of 3-12 when comparing cine and fluoroscopy frames. The biggest difference in the signal-to- noise ratio between fluoroscopy and cine modes occurs at FOV 32 cm because fluoroscopy is acquired at a 1440 × 1440 pixel matrix size and in unbinned mode, whereas cine is acquired at 720 × 720 pixels and in binned mode. The high-contrast spatial resolution of cine is better than that of fluoroscopy, except for FOV 32 cm, because fluoroscopy mode with 32 cm FOV is unbinned. Acquiring CBCT series with a 16 cm head phantom using the standard dose protocol results in a threefold dose increase compared with the low-dose protocol. Although the amount of noise present in the images acquired with the low-dose protocol is much higher than that obtained with the standard mode, the images present better spatial resolution. A 1 mm diameter rod with 250 Hounsfield units can be distinguished in reconstructed images with an 8 mm slice width. Pediatric-specific protocols provide lower doses while maintaining sufficient image quality. The system offers a novel 3D imaging mode. The acquisition of CBCT images results in increased doses administered to the patients, but also provides further diagnostic information contained in the volumetric images. The assessed CBCT protocols provide images that are noisy, but with very good spatial resolution. © 2016 The Authors.

Low dose tomographic fluoroscopy: 4D intervention guidance with running prior

DOE Office of Scientific and Technical Information (OSTI.GOV)

Flach, Barbara; Kuntz, Jan; Brehm, Marcus

Purpose: Today's standard imaging technique in interventional radiology is the single- or biplane x-ray fluoroscopy which delivers 2D projection images as a function of time (2D+T). This state-of-the-art technology, however, suffers from its projective nature and is limited by the superposition of the patient's anatomy. Temporally resolved tomographic volumes (3D+T) would significantly improve the visualization of complex structures. A continuous tomographic data acquisition, if carried out with today's technology, would yield an excessive patient dose. Recently the authors proposed a method that enables tomographic fluoroscopy at the same dose level as projective fluoroscopy which means that if scanning time ofmore » an intervention guided by projective fluoroscopy is the same as that of an intervention guided by tomographic fluoroscopy, almost the same dose is administered to the patient. The purpose of this work is to extend authors' previous work and allow for patient motion during the intervention.Methods: The authors propose the running prior technique for adaptation of a prior image. This adaptation is realized by a combination of registration and projection replacement. In a first step the prior is deformed to the current position via affine and deformable registration. Then the information from outdated projections is replaced by newly acquired projections using forward and backprojection steps. The thus adapted volume is the running prior. The proposed method is validated by simulated as well as measured data. To investigate motion during intervention a moving head phantom was simulated. Real in vivo data of a pig are acquired by a prototype CT system consisting of a flat detector and a continuously rotating clinical gantry.Results: With the running prior technique it is possible to correct for motion without additional dose. For an application in intervention guidance both steps of the running prior technique, registration and replacement, are necessary. Reconstructed volumes based on the running prior show high image quality without introducing new artifacts and the interventional materials are displayed at the correct position.Conclusions: The running prior improves the robustness of low dose 3D+T intervention guidance toward intended or unintended patient motion.« less

SU-F-I-77: Radiation Dose in Cardiac Catheterization Procedures: Impact of a Systematic Reduction in Pulsed Fluoroscopy Frame Rate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schultz, C; Dixon, S

Purpose: To evaluate whether one small systematic reduction in fluoroscopy frame rate has a significant effect on the total air kerma and/or dose area product for diagnostic and interventional cardiac catheterization procedures. Methods: The default fluoroscopy frame rate (FFR) was lowered from 15 to 10 fps in 5 Siemens™ Axiom Artis cardiac catheterization labs (CCL) on July 1, 2013. A total of 7212 consecutive diagnostic and interventional CCL procedures were divided into two study groups: 3602 procedures from 10/1/12 –6/30/13 with FFR of 15 fps; and 3610 procedures 7/1/13 – 3/31/14 at 10 fps. For each procedure, total air kermamore » (TAK), fluoroscopy skin dose (FSD), total/fluoroscopy dose area products (TAD, FAD), and total fluoroscopy time (FT) were recorded. Patient specific data collected for each procedure included: BSA, sex, height, weight, interventional versus diagnostic; and elective versus emergent. Results: For pre to post change in FFR, each categorical variable was compared using Pearson’s Chi-square test, Odds ratios and 95% confidence intervals. No statistically significant difference in BSA, height, weight, number of interventional versus diagnostic, elective versus emergent procedures was found between the two study groups. Decreasing the default FFR from 15 fps to 10 fps in the two study groups significantly reduced TAK from 1305 to 1061 mGy (p<0.0001), FSD from 627 to 454 mGy (p<0.0001), TAD from 8681 to 6991 uGy × m{sup 2}(p<0.0001), and FAD from 4493 to 3297 uGy × m{sup 2}(p<0.0001). No statistically significant difference in FT was noted. Clinical image quality was not analyzed, and reports of noticeable effects were minimal. From July 1, 2013 to date, the default FFR has remained 10 fps. Conclusion: Reducing the FFR from 15 to 10 fps significantly reduced total air kerma and dose area product which may decrease risk for potential radiation-induced skin injuries and improve patient outcomes.« less

Detecting condylar contact loss using single-plane fluoroscopy: a comparison with in vivo force data and in vitro bi-plane data.

PubMed

Prins, A H; Kaptein, B L; Banks, S A; Stoel, B C; Nelissen, R G H H; Valstar, E R

2014-05-07

Knee contact mechanics play an important role in knee implant failure and wear mechanics. Femoral condylar contact loss in total knee arthroplasty has been reported in some studies and it is considered to potentially induce excessive wear of the polyethylene insert.Measuring in vivo forces applied to the tibial plateau with an instrumented prosthesis is a possible approach to assess contact loss in vivo, but this approach is not very practical. Alternatively, single-plane fluoroscopy and pose estimation can be used to derive the relative pose of the femoral component with respect to the tibial plateau and estimate the distance from the medial and lateral parts of the femoral component towards the insert. Two measures are reported in the literature: lift-off is commonly defined as the difference in distance between the medial and lateral condyles of the femoral component with respect to the tibial plateau; separation is determined by the closest distance of each condyle towards the polyethylene insert instead of the tibia plateau.In this validation study, lift-off and separation as measured with single-plane fluoroscopy are compared to in vivo contact forces measured with an instrumented knee implant. In a phantom study, lift-off and separation were compared to measurements with a high quality bi-plane measurement.The results of the in vivo contact-force experiment demonstrate a large discrepancy between single-plane fluoroscopy and the in vivo force data: single-plane fluoroscopy measured up to 5.1mm of lift-off or separation, whereas the force data never showed actual loss of contact. The phantom study demonstrated that the single-plane setup could introduce an overestimation of 0.22mm±±0.36mm. Correcting the out-of-plane position resulted in an underestimation of medial separation by -0.20mm±±0.29mm.In conclusion, there is a discrepancy between the in vivo force data and single-plane fluoroscopic measurements. Therefore contact loss may not always be determined reliably by single plane fluoroscopy analysis. Copyright © 2014 Elsevier Ltd. All rights reserved.

SU-G-JeP4-12: Real-Time Organ Motion Monitoring Using Ultrasound and KV Fluoroscopy During Lung SBRT Delivery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Omari, E; Tai, A; Li, X

Purpose: Real-time ultrasound monitoring during SBRT is advantageous in understanding and identifying motion irregularities which may cause geometric misses. In this work, we propose to utilize real-time ultrasound to track the diaphragm in conjunction with periodical kV fluoroscopy to monitor motion of tumor or landmarks during SBRT delivery. Methods: Transabdominal Ultrasound (TAUS) b-mode images were collected from 10 healthy volunteers using the Clarity Autoscan System (Elekta). The autoscan transducer, which has a center frequency of 5 MHz, was utilized for the scans. The acquired images were contoured using the Clarity Automatic Fusion and Contouring workstation software. Monitoring sessions of 5more » minute length were observed and recorded. The position correlation between tumor and diaphragm could be established with periodic kV fluoroscopy periodically acquired during treatment with Elekta XVI. We acquired data using a tissue mimicking ultrasound phantom with embedded spheres placed on a motion stand using ultrasound and kV Fluoroscopy. MIM software was utilized for image fusion. Correlation of diaphragm and target motion was also validated using 4D-MRI and 4D-CBCT. Results: The diaphragm was visualized as a hyperechoic region on the TAUS b-mode images. Volunteer set-up can be adjusted such that TAUS probe will not interfere with treatment beams. A segment of the diaphragm was contoured and selected as our tracking structure. Successful monitoring sessions of the diaphragm were recorded. For some volunteers, diaphragm motion over 2 times larger than the initial motion has been observed during tracking. For the phantom study, we were able to register the 2D kV Fluoroscopy with the US images for position comparison. Conclusion: We demonstrated the feasibility of tracking the diaphragm using real-time ultrasound. Real-time tracking can help in identifying such irregularities in the respiratory motion which is correlated to tumor motion. We also showed the feasibility of acquiring 2D KV Fluoroscopy and registering the images with Ultrasound.« less

Comparative ergonomic workflow and user experience analysis of MRI versus fluoroscopy-guided vascular interventions: an iliac angioplasty exemplar case study.

PubMed

Fernández-Gutiérrez, Fabiola; Martínez, Santiago; Rube, Martin A; Cox, Benjamin F; Fatahi, Mahsa; Scott-Brown, Kenneth C; Houston, J Graeme; McLeod, Helen; White, Richard D; French, Karen; Gueorguieva, Mariana; Immel, Erwin; Melzer, Andreas

2015-10-01

A methodological framework is introduced to assess and compare a conventional fluoroscopy protocol for peripheral angioplasty with a new magnetic resonant imaging (MRI)-guided protocol. Different scenarios were considered during interventions on a perfused arterial phantom with regard to time-based and cognitive task analysis, user experience and ergonomics. Three clinicians with different expertise performed a total of 43 simulated common iliac angioplasties (9 fluoroscopic, 34 MRI-guided) in two blocks of sessions. Six different configurations for MRI guidance were tested in the first block. Four of them were evaluated in the second block and compared to the fluoroscopy protocol. Relevant stages' durations were collected, and interventions were audio-visually recorded from different perspectives. A cued retrospective protocol analysis (CRPA) was undertaken, including personal interviews. In addition, ergonomic constraints in the MRI suite were evaluated. Significant differences were found when comparing the performance between MRI configurations versus fluoroscopy. Two configurations [with times of 8.56 (0.64) and 9.48 (1.13) min] led to reduce procedure time for MRI guidance, comparable to fluoroscopy [8.49 (0.75) min]. The CRPA pointed out the main influential factors for clinical procedure performance. The ergonomic analysis quantified musculoskeletal risks for interventional radiologists when utilising MRI. Several alternatives were suggested to prevent potential low-back injuries. This work presents a step towards the implementation of efficient operational protocols for MRI-guided procedures based on an integral and multidisciplinary framework, applicable to the assessment of current vascular protocols. The use of first-user perspective raises the possibility of establishing new forms of clinical training and education.

Descriptive Cadaveric Study Comparing the Accuracy of Ultrasound Versus Fluoroscopic Guidance for First Sacral Transforaminal Injections: A Comparison Study.

PubMed

Thompson, Bradley F; Pingree, Matthew J; Qu, Wenchun; Murthy, Naveen S; Lachman, Nirusha; Hurdle, Mark Friedrich

2018-04-01

Ultrasound is rarely used for guiding lumbosacral epidural steroid injections due to its technical limitations. For example, sonographic imaging lacks the ability to confirm epidural spread and identify vascular uptake. The perceived risk that these limitations pose to human subjects has precluded any large scale clinical trials to date. To compare the accuracy of ultrasound versus fluoroscopic guidance for first sacral transforaminal epidural injections. Cadaveric comparative study using dichotomous outcomes. A fluoroscopy suite and anatomic laboratory at an academic medical center. Four unembalmed adult human cadavers with no history of spinal surgery. Eight sites were injected twice by one interventionalist, using fluoroscopic and ultrasound guidance. In the fluoroscopy arm, contrast spread was assessed using computed tomography. In the ultrasound arm, latex spread was assessed using gross anatomic dissection. Any visible evidence of epidural spread constituted a positive result. Comparison of the success of obtaining epidural contrast flow was the primary outcome measure. Secondary outcome measures included average duration, rate of intravascular uptake, and quantity of intravascular uptake. All injections performed in both the ultrasound arm and the fluoroscopy arm had positive epidural spread. The average duration was 3.03 minutes with fluoroscopy and 4.76 minutes with ultrasound. The rate of intravascular uptake was 37.5% with fluoroscopy and 50% with ultrasound. Within the ultrasound arm, greater intravascular spread and duration variability were recorded. Although ultrasonography can provide reliable image guidance for cannulating the first sacral foramen in cadavers, it would have limited clinical utility due to its inability to visualize relevant neurovascular structures deep to the osseus roof and exclude intravascular uptake. IV. Copyright © 2018 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

Optimal angle of needle insertion for fluoroscopy-guided transforaminal epidural injection of L5.

PubMed

Ra, In-Hoo; Min, Woo-Kie

2015-06-01

Unlike other sites, there is difficulty in performing TFESI at the L5-S1 level because the iliac crest is an obstacle to needle placement. The objective of this study was to identify the optimal angle of fluoroscopy for insertion and advancement of a needle during L5 TEFSI. We conducted an observational study of patients undergoing fluoroscopy-guided L5 TFESI in the prone position. A total of 80 patients (40 men and 40 women) with radiating pain of lower limbs were enrolled. During TFESI, we measured the angle at which the L5 vertebral body forms a rectangular shape and compared men and women. Then, we measured area of safe triangle in tilting angle of fluoroscopy from 15° to 35° and compared men and women. The mean cephalocaudal angle, where the vertebral body takes the shape of a rectangle, was 11.0° in men and 13.9° in women (P = 0.007). In men, the triangular area was maximal at 18.3 mm² with an oblique view angle of 25°. In women, the area was maximal at 23.6 mm² with an oblique view angle of 30°. At an oblique view angle of 30° and 35°, the area was significantly greater in women (P < 0.05). When TFESI is performed at the L5 region in the prone position, placement of fluoroscopy at a cephalocaudal angle of 11.0° and an oblique angle of 25° in men and cephalocaudal angle of 13.9° and an oblique angle of 30° in women would be most reasonable. © 2014 World Institute of Pain.

Non-fluoroscopic navigation systems for radiofrequency catheter ablation for supraventricular tachycardia reduce ionising radiation exposure.

PubMed

See, Jason; Amora, Jonah L; Lee, Sheldon; Lim, Paul; Teo, Wee Siong; Tan, Boon Yew; Ho, Kah Leng; Lee, Chee Wan; Ching, Chi-Keong

2016-07-01

The use of non-fluoroscopic systems (NFS) to guide radiofrequency catheter ablation (RFCA) for the treatment of supraventricular tachycardia (SVT) is associated with lower radiation exposure. This study aimed to determine if NFS reduces fluoroscopy time, radiation dose and procedure time. We prospectively enrolled patients undergoing RFCA for SVT. NFS included EnSiteTM NavXTM or CARTO® mapping. We compared procedure and fluoroscopy times, and radiation exposure between NFS and conventional fluoroscopy (CF) cohorts. Procedural success, complications and one-year success rates were reported. A total of 200 patients over 27 months were included and RFCA was guided by NFS for 79 patients; those with atrioventricular nodal reentrant tachycardia (AVNRT), left-sided atrioventricular reentrant tachycardia (AVRT) and right-sided AVRT were included (n = 101, 63 and 36, respectively). Fluoroscopy times were significantly lower with NFS than with CF (10.8 ± 11.1 minutes vs. 32.0 ± 27.5 minutes; p < 0.001). The mean fluoroscopic dose area product was also significantly reduced with NFS (NSF: 5,382 ± 5,768 mGy*cm2 vs. CF: 21,070 ± 23,311 mGy*cm2; p < 0.001); for all SVT subtypes. There was no significant reduction in procedure time, except for left-sided AVRT ablation (NFS: 79.2 minutes vs. CF: 116.4 minutes; p = 0.001). Procedural success rates were comparable (NFS: 97.5% vs. CF: 98.3%) and at one-year follow-up, there was no significant difference in the recurrence rates (NFS: 5.2% vs. CF: 4.2%). No clinically significant complications were observed in both groups. The use of NFS for RFCA for SVT is safe, with significantly reduced radiation dose and fluoroscopy time. Copyright © Singapore Medical Association.

Sensitivity of the diagnostic radiological index of protection to procedural factors in fluoroscopy.

PubMed

Jones, A Kyle; Pasciak, Alexander S; Wagner, Louis K

2016-07-01

To evaluate the sensitivity of the diagnostic radiological index of protection (DRIP), used to quantify the protective value of radioprotective garments, to procedural factors in fluoroscopy in an effort to determine an appropriate set of scatter-mimicking primary beams to be used in measuring the DRIP. Monte Carlo simulations were performed to determine the shape of the scattered x-ray spectra incident on the operator in different clinical fluoroscopy scenarios, including interventional radiology and interventional cardiology (IC). Two clinical simulations studied the sensitivity of the scattered spectrum to gantry angle and patient size, while technical factors were varied according to measured automatic dose rate control (ADRC) data. Factorial simulations studied the sensitivity of the scattered spectrum to gantry angle, field of view, patient size, and beam quality for constant technical factors. Average energy (Eavg) was the figure of merit used to condense fluence in each energy bin to a single numerical index. Beam quality had the strongest influence on the scattered spectrum in fluoroscopy. Many procedural factors affect the scattered spectrum indirectly through their effect on primary beam quality through ADRC, e.g., gantry angle and patient size. Lateral C-arm rotation, common in IC, increased the energy of the scattered spectrum, regardless of the direction of rotation. The effect of patient size on scattered radiation depended on ADRC characteristics, patient size, and procedure type. The scattered spectrum striking the operator in fluoroscopy is most strongly influenced by primary beam quality, particularly kV. Use cases for protective garments should be classified by typical procedural primary beam qualities, which are governed by the ADRC according to the impacts of patient size, anatomical location, and gantry angle.

Personalized Feedback on Staff Dose in Fluoroscopy-Guided Interventions: A New Era in Radiation Dose Monitoring.

PubMed

Sailer, Anna M; Vergoossen, Laura; Paulis, Leonie; van Zwam, Willem H; Das, Marco; Wildberger, Joachim E; Jeukens, Cécile R L P N

2017-11-01

Radiation safety and protection are a key component of fluoroscopy-guided interventions. We hypothesize that providing weekly personal dose feedback will increase radiation awareness and ultimately will lead to optimized behavior. Therefore, we designed and implemented a personalized feedback of procedure and personal doses for medical staff involved in fluoroscopy-guided interventions. Medical staff (physicians and technicians, n = 27) involved in fluoroscopy-guided interventions were equipped with electronic personal dose meters (PDMs). Procedure dose data including the dose area product and effective doses from PDMs were prospectively monitored for each consecutive procedure over an 8-month period (n = 1082). A personalized feedback form was designed displaying for each staff individually the personal dose per procedure, as well as relative and cumulative doses. This study consisted of two phases: (1) 1-5th months: Staff did not receive feedback (n = 701) and (2) 6-8th months: Staff received weekly individual dose feedback (n = 381). An anonymous evaluation was performed on the feedback and occupational dose. Personalized feedback was scored valuable by 76% of the staff and increased radiation dose awareness for 71%. 57 and 52% reported an increased feeling of occupational safety and changing their behavior because of personalized feedback, respectively. For technicians, the normalized dose was significantly lower in the feedback phase compared to the prefeedback phase: [median (IQR) normalized dose (phase 1) 0.12 (0.04-0.50) µSv/Gy cm 2 versus (phase 2) 0.08 (0.02-0.24) µSv/Gy cm 2 , p = 0.002]. Personalized dose feedback increases radiation awareness and safety and can be provided to staff involved in fluoroscopy-guided interventions.

Double needle technique: an alternative method for performing difficult sacroiliac joint injections.

PubMed

Gupta, Sanjeeva

2011-01-01

The sacroiliac joint (SIJ) is a common source of low back pain. The most appropriate method of confirming SIJ pain is to inject local anesthesia into the joint to find out if the pain decreases. Unfortunately, although the SIJ is a large joint, it can be difficult to enter due to the complex nature of the joint and variations in anatomy. In my experience a double needle technique for sacroiliac joint injection can increase the chances of accurate injection into the SIJ in difficult cases. After obtaining appropriate fluoroscopic images, the tip of the needle is advanced into the SIJ. Once the tip of the needle is correctly placed, its position is checked under continuous fluoroscopy while moving the C-arm in the right and left oblique directions (dynamic fluoroscopy). On dynamic fluoroscopy the tip of the needle should remain within the joint line and not appear to be on the bone. If the tip of the needle appears to be on the bone a new joint line will need to be identified (the most translucent area through the joint) by dynamic fluoroscopy and another needle advanced into the newly identified joint line. Dynamic fluoroscopy is repeated again to confirm that the tip of the second needle remains within the joint line. Once both needles are in place contrast dye is injected through the needle that is most likely to be in the SIJ. If the contrast dye spread is not satisfactory then it is injected through the other needle. I have used this technique in 10 patients and found it very helpful in accurately performing SIJ injection which can at times be challenging.

MO-F-16A-04: Case Study: Estimation of Peak Skin Dose Following a Physician Reported “High Dose” Case and Sentinel Event Considerations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Supanich, M; Chu, J; Wehmeyer, A

2014-06-15

Purpose: This work offers as a teaching example a reported high dose fluoroscopy case and the workflow the institution followed to self-report a radiation overdose sentinel event to the Joint Commission. Methods: Following the completion of a clinical case in a hybrid OR room with a reported air kerma of >18 Gy at the Interventional Reference Point (IRP) the physicians involved in the case referred study to the institution's Radiation Safety Committee (RSC) for review. The RSC assigned a Diagnostic Medical Physicist (DMP) to estimate the patient's Peak Skin Dose (PSD) and analyze the case. Following the DMP's analysis andmore » estimate of a PSD of >15 Gy the institution's adverse event committee was convened to discuss the case and to self-report the case as a radiation overdose sentinel event to the Joint Commission. The committee assigned a subgroup to perform the root cause analysis and develop institutional responses to the event. Results: The self-reporting of the sentinel event and the associated root cause analysis resulted in several institutional action items that are designed to improve process and safety. A formal reporting and analysis mechanism was adopted to review fluoroscopy cases with air kerma greater than 6 Gy at the IRP. An improved and formalized radiation safety training program for physicians using fluoroscopy equipment was implemented. Additionally efforts already under way to monitor radiation exposure in the Radiology department were expanded to include all fluoroscopy equipment capable of automated dose reporting. Conclusion: The adverse event review process and the root cause analysis following the self-reporting of the sentinel event resulted in policies and procedures that are expected to improve the quality and safe usage of fluoroscopy throughout the institution.« less

An Outcome and Cost Analysis Comparing Single-Level Minimally Invasive Transforaminal Lumbar Interbody Fusion Using Intraoperative Fluoroscopy versus Computed Tomography-Guided Navigation.

PubMed

Khanna, Ryan; McDevitt, Joseph L; Abecassis, Zachary A; Smith, Zachary A; Koski, Tyler R; Fessler, Richard G; Dahdaleh, Nader S

2016-10-01

Minimally invasive transforaminal lumbar interbody fusion (TLIF) has undergone significant evolution since its conception as a fusion technique to treat lumbar spondylosis. Minimally invasive TLIF is commonly performed using intraoperative two-dimensional fluoroscopic x-rays. However, intraoperative computed tomography (CT)-based navigation during minimally invasive TLIF is gaining popularity for improvements in visualizing anatomy and reducing intraoperative radiation to surgeons and operating room staff. This is the first study to compare clinical outcomes and cost between these 2 imaging techniques during minimally invasive TILF. For comparison, 28 patients who underwent single-level minimally invasive TLIF using fluoroscopy were matched to 28 patients undergoing single-level minimally invasive TLIF using CT navigation based on race, sex, age, smoking status, payer type, and medical comorbidities (Charlson Comorbidity Index). The minimum follow-up time was 6 months. The 2 groups were compared in regard to clinical outcomes and hospital reimbursement from the payer perspective. Average surgery time, anesthesia time, and hospital length of stay were similar for both groups, but average estimated blood loss was lower in the fluoroscopy group compared with the CT navigation group (154 mL vs. 262 mL; P = 0.016). Oswestry Disability Index, back visual analog scale, and leg visual analog scale scores similarly improved in both groups (P > 0.05) at 6-month follow-up. Cost analysis showed that average hospital payments were similar in the fluoroscopy versus the CT navigation groups ($32,347 vs. $32,656; P = 0.925) as well as payments for the operating room (P = 0.868). Single minimally invasive TLIF performed with fluoroscopy versus CT navigation showed similar clinical outcomes and cost at 6 months. Copyright © 2016 Elsevier Inc. All rights reserved.

Predictors of radiation exposure to providers during percutaneous nephrolithotomy

PubMed Central

Wenzler, David L.; Abbott, Joel E.; Su, Jeannie J.; Shi, William; Slater, Richard; Miller, Daniel; Siemens, Michelle J.; Sur, Roger L.

2017-01-01

Background: Limited studies have reported on radiation risks of increased ionizing radiation exposure to medical personnel in the urologic community. Fluoroscopy is readily used in many urologic surgical procedures. The aim of this study was to determine radiation exposure to all operating room personnel during percutaneous nephrolithotomy (PNL), commonly performed for large renal or complex stones. Materials and Methods: We prospectively collected personnel exposure data for all PNL cases at two academic institutions. This was collected using the Instadose™ dosimeter and reported both continuously and categorically as high and low dose using a 10 mrem dose threshold, the approximate amount of radiation received from one single chest X-ray. Predictors of increased radiation exposure were determined using multivariate analysis. Results: A total of 91 PNL cases in 66 patients were reviewed. Median surgery duration and fluoroscopy time were 142 (38–368) min and 263 (19–1809) sec, respectively. Median attending urologist, urology resident, anesthesia, and nurse radiation exposure per case was 4 (0–111), 4 (0–21), 0 (0–5), and 0 (0–5) mrem, respectively. On univariate analysis, stone area, partial or staghorn calculi, surgery duration, and fluoroscopy time were associated with high attending urologist and resident radiation exposure. Preexisting access that was utilized was negatively associated with resident radiation exposure. However, on multivariate analysis, only fluoroscopy duration remained significant for attending urologist radiation exposure. Conclusion: Increased stone burden, partial or staghorn calculi, surgery and fluoroscopy duration, and absence of preexisting access were associated with high provider radiation exposure. Radiation safety awareness is essential to minimize exposure and to protect the patient and all providers from potential radiation injury. PMID:28216931

Technical results and effects of operator experience on uterine artery embolization for fibroids: the Ontario Uterine Fibroid Embolization Trial.

PubMed

Pron, Gaylene; Bennett, John; Common, Andrew; Sniderman, Kenneth; Asch, Murray; Bell, Stuart; Kozak, Roman; Vanderburgh, Leslie; Garvin, Greg; Simons, Martin; Tran, Cuong; Kachura, John

2003-05-01

To document the technical results and spectrum of practice of uterine artery embolization (UAE) for fibroids in the health care setting in Canada. The effects of interventional radiologist's (IR's) experience with UAE on procedure and fluoroscopy time were also investigated. The study involved a multicenter prospective single-arm clinical treatment trial and included the practices of 11 IRs at eight university-affiliated teaching and community hospitals. Vascular access with percutaneous femoral artery approach was followed by transcatheter delivery of polyvinyl alcohol (PVA) particles into uterine arteries with fluoroscopic guidance. Technical success, complications, procedural time, fluoroscopy time, and effects of operator experience were outcomes analyzed. Between November 1998 and November 2000, 570 embolization procedures were performed in 555 patients. UAE was bilaterally successful in 97% (95% CI: 95%-98%). Variant anatomy was the most common reason for failure to embolize bilaterally. The procedural complication rate was 5.3% (95% CI: 3.6%-7.4%). Of the 30 events, three involved major complications (one seizure and two allergic reactions) that resulted in additional care or extended hospital stay. Procedure time and fluoroscopy time averaged 61 minutes (95% CI; 58-63 minutes) and 18.9 minutes (95% CI; 18-19.8) and varied significantly among IRs (P <.001; P <.001). The average 27% reduction in procedure time (20 minutes; P <.001) and 24% reduction in fluoroscopy time (5.1 minutes; P <.001) with increasing UAE experience were significant. A high level of technical success with few complications was obtained with a variety of operators in diverse practice settings. Increased experience in UAE significantly reduced procedure and fluoroscopy time.

Effective doses in children: association with common complex imaging techniques used during interventional radiology procedures.

PubMed

Lai, Priscilla; McNeil, Sarah M; Gordon, Christopher L; Connolly, Bairbre L

2014-12-01

The purpose of this study was to determine the range of effective doses associated with imaging techniques used during interventional radiology procedures on children. A pediatric phantom set (1, 5, and 10 years) coupled with high-sensitivity metal oxide semiconductor field effect transistor (MOSFET) dosimeters was used to calculate effective doses. Twenty MOSFETs were inserted into each phantom at radiosensitive organ locations. The phantoms were exposed to mock head, chest, and abdominal interventional radiology procedures performed with different geometries and magnifications. Fluoroscopy, digital subtraction angiography (DSA), and spin angiography were simulated on each phantom. Road mapping was conducted only on the 5-year-old phantom. International Commission on Radiological Protection publication 103 tissue weights were applied to the organ doses recorded with the MOSFETs to determine effective dose. For easy application to clinical cases, doses were normalized per minute of fluoroscopy and per 10 frames of DSA or spin angiography. Effective doses from DSA, angiography, and fluoroscopy were higher for younger ages because of magnification use and were largest for abdominal procedures. DSA of the head, chest, and abdomen (normalized per 10 frames) imparted doses 2-3 times as high as corresponding doses per minute of fluoroscopy while all other factors remained unchanged (age, projection, collimation, magnification). Three to five frames of DSA imparted an effective dose equal to doses from 1 minute of fluoroscopy. Doses from spin angiography were almost one-half the doses received from an equivalent number of frames of DSA. Patient effective doses during interventional procedures vary substantially depending on procedure type but tend to be higher because of magnification use in younger children and higher in the abdomen.

Reducing intraoperative duration and ionising radiation exposure during the insertion of distal locking screws of intramedullary nails: a small-scale study comparing the current fluoroscopic method against radiation-free, electromagnetic navigation.

PubMed

Grimwood, Darren; Harvey-Lloyd, Jane

2016-12-01

Intramedullary nailing is the standard surgical treatment for mid-diaphyseal fractures of long bones; however, it is also a high radiation dose procedure. Distal locking is regularly cited as a demanding element of the procedure, and there remains a reliance on X-ray fluoroscopy to locate the distal holes. A recently developed electromagnetic navigation (EMN) system allows radiation-free distal locking, with a virtual on-screen image. To compare operative duration, fluoroscopy time and radiation dose when using EMN over fluoroscopy, for the distal locking of intramedullary nails. Consecutive patients with mid-diaphyseal fractures of the tibia and femur, treatable with intramedullary nails, were prospectively enrolled during a 9-month period. The sample consisted of 29 individuals, 19 under fluoroscopic guidance and 10 utilising EMN. Participants were allocated depending on the type of intramedullary nail used and surgeon's preference. These were further divided into tibial and femoral subcategories, relative to the fracture site. EMN reduced fluoroscopy time by 49 (p = 0.038) and 28 s during tibial and femoral nailings, respectively. Radiation dose was reduced by 18 cGy/cm 2 (p = 0.046) during tibial and 181 cGy/cm 2 during femoral nailings when utilising EMN. Operative duration was 11 min slower during tibial nailings using EMN, but 38 min faster in respect of femoral nailings. This study has evidenced statistically significant reductions in both fluoroscopy time and radiation dose when using EMN for the distal locking of intramedullary nails. It is expected that overall operative duration would also decrease in line with similar studies, with increased usage and a larger sample.

CT Guided Bone Biopsy Using a Battery Powered Intraosseous Device

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schnapauff, Dirk, E-mail: dirk.schnapauff@charite.de; Marnitz, Tim, E-mail: tim.marnitz@charite.de; Freyhardt, Patrick, E-mail: Patrick.freyhardt@charite.de

2013-10-15

Purpose: To evaluate the feasibility of a battery powered intraosseous device to perform CT-fluoroscopy guided bone biopsy. Methods: Retrospective analysis of 12 patients in whom bone specimen were acquired from different locations under CT-fluoroscopy guidance using the OnControl bone marrow biopsy system (OBM, Vidacare, Shavano Park, TX, USA). Data of the 12 were compared to a historic cohort in whom the specimen were acquired using the classic Jamshidi Needle, as reference needle using manual force for biopsy. Results: Technical success was reached in 11 of 12 cases, indicated by central localisation of the needle within the target lesion. All specimenmore » sampled were sufficient for histopathological workup. Compared to the historical cohort the time needed for biopsy decreased significantly from 13 {+-} 6 to 6 {+-} 4 min (P = 0.0001). Due to the shortened intervention time the radiation dose (CTDI) during CT-fluoroscopy was lowered significantly from 169 {+-} 87 to 111 {+-} 54 mGy Multiplication-Sign cm (P = 0.0001). Interventional radiologists were confident with the performance of the needle especially when using in sclerotic or osteoblastic lesions. Conclusion: The OBM is an attractive support for CT-fluoroscopy guided bone biopsy which is safe tool and compared to the classical approach using the Jamshidi needle leading to significantly reduced intervention time and radiation exposure.« less

Emergency endotracheal intubation under fluoroscopy guidance for patients with acute dyspnea or asphyxia.

PubMed

Jiao, Dechao; Xie, Na; Han, Xinwei; Wu, Gang

2016-11-01

To evaluate the feasibility and effectiveness of emergency endotracheal intubation (EEI) under fluoroscopy guidance for patients with acute dyspnea or asphyxia. From October 2011 to October 2014, of 1521 patients with acute dyspnea or asphyxia who required EEI in 6 departments, 43 patients who experienced intubation difficulty or failure were entered into this study. Data on technical success, procedure time, complications, and clinical outcome were collected. The pulse oxygen saturation and Hugh-Jones classification changes were analyzed. Fluoroscopy-guided EEI was technically successful in all patients. Acute dyspnea had resolved in all patients with clinical success rate 100% after the procedure. There were no serious complications during or after the procedure. The pulse oxygen saturation and Hugh-Jones classification showed significant increase after EEI (P < .05). Further treatments, including tracheal stents (n = 21), surgical resection (n = 16), palliative tracheotomy (n = 4), and bronchoscopic treatment (n = 2), were performed 1 to 72 hours after EEI. During a mean follow-up period of 13.2 months, 13 patients had died and 30 patients remained alive without dyspnea. Fluoroscopy-guided EEI is a safe and feasible procedure, and may serve as an alternative treatment option for patients when traditional EEI is unsuccessful. Copyright © 2016 Elsevier Inc. All rights reserved.

Radiation exposure and contrast agent use related to radial versus femoral arterial access during percutaneous coronary intervention (PCI)-Results of the FERARI study.

PubMed

Becher, Tobias; Behnes, Michael; Ünsal, Melike; Baumann, Stefan; El-Battrawy, Ibrahim; Fastner, Christian; Kuschyk, Jürgen; Papavassiliu, Theano; Hoffmann, Ursula; Mashayekhi, Kambis; Borggrefe, Martin; Akin, Ibrahim

2016-12-01

Data regarding radiation exposure related to radial versus femoral arterial access in patients undergoing percutaneous coronary intervention (PCI) remain controversial. This study aims to evaluate patients enrolled in the FERARI study regarding radiation exposure, fluoroscopy time and contrast agent use. The Femoral Closure versus Radial Compression Devices Related to Percutaneous Coronary Interventions (FERARI) study evaluated prospectively 400 patients between February 2014 and May 2015 undergoing PCI either using the radial or femoral access. In these 400 patients, baseline characteristics, procedural data such as procedural duration, fluoroscopy time, dose-area product (DAP) as well as the amount of contrast agent used were documented and analyzed. Median fluoroscopy time was not significantly different in patients undergoing radial versus femoral access (12.2 vs. 9.8min, p=0.507). Furthermore, median DAP (54.5 vs. 52.0 Gycm2, p=0.826), procedural duration (46.0 vs. 45.0min, p=0.363) and contrast agent use (185.5 vs. 199.5ml, p=0.742) were also similar in radial and femoral PCI. There was no difference regarding median fluoroscopy time, procedural duration, radiation dose or contrast agent use between radial versus femoral arterial access in PCI. Copyright © 2016 Elsevier Inc. All rights reserved.

Cone-Beam Computed Tomography Internal Motion Tracking Should Be Used to Validate 4-Dimensional Computed Tomography for Abdominal Radiation Therapy Patients

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rankine, Leith; Wan, Hanlin; Parikh, Parag

Purpose: To demonstrate that fiducial tracking during pretreatment Cone-Beam CT (CBCT) can accurately measure tumor motion and that this method should be used to validate 4-dimensional CT (4DCT) margins before each treatment fraction. Methods and Materials: For 31 patients with abdominal tumors and implanted fiducial markers, tumor motion was measured daily with CBCT and fluoroscopy for 202 treatment fractions. Fiducial tracking and maximum-likelihood algorithms extracted 3-dimensional fiducial trajectories from CBCT projections. The daily internal margin (IM) (ie, range of fiducial motion) was calculated for CBCT and fluoroscopy as the 5th-95th percentiles of displacement in each cardinal direction. The planning IMmore » from simulation 4DCT (IM{sub 4DCT}) was considered adequate when within ±1.2 mm (anterior–posterior, left–right) and ±3 mm (superior–inferior) of the daily measured IM. We validated CBCT fiducial tracking as an accurate predictive measure of intrafraction motion by comparing the daily measured IM{sub CBCT} with the daily IM measured by pretreatment fluoroscopy (IM{sub pre-fluoro}); these were compared with pre- and posttreatment fluoroscopy (IM{sub fluoro}) to identify those patients who could benefit from imaging during treatment. Results: Four-dimensional CT could not accurately predict intrafractional tumor motion for ≥80% of fractions in 94% (IM{sub CBCT}), 97% (IM{sub pre-fluoro}), and 100% (IM{sub fluoro}) of patients. The IM{sub CBCT} was significantly closer to IM{sub pre-fluoro} than IM{sub 4DCT} (P<.01). For patients with median treatment time t < 7.5 minutes, IM{sub CBCT} was in agreement with IM{sub fluoro} for 93% of fractions (superior–inferior), compared with 63% for the t > 7.5 minutes group, demonstrating the need for patient-specific intratreatment imaging. Conclusions: Tumor motion determined from 4DCT simulation does not accurately predict the daily motion observed on CBCT or fluoroscopy. Cone-beam CT could replace fluoroscopy for pretreatment verification of simulation IM{sub 4DCT}, reducing patient setup time and imaging dose. Patients with treatment time t > 7.5 minutes could benefit from the addition of intratreatment imaging.« less

Percutaneous pedicle screw placement under single dimensional fluoroscopy with a designed pedicle finder-a technical note and case series.

PubMed

Tsuang, Fon-Yih; Chen, Chia-Hsien; Kuo, Yi-Jie; Tseng, Wei-Lung; Chen, Yuan-Shen; Lin, Chin-Jung; Liao, Chun-Jen; Lin, Feng-Huei; Chiang, Chang-Jung

2017-09-01

Minimally invasive spine surgery has become increasingly popular in clinical practice, and it offers patients the potential benefits of reduced blood loss, wound pain, and infection risk, and it also diminishes the loss of working time and length of hospital stay. However, surgeons require more intraoperative fluoroscopy and ionizing radiation exposure during minimally invasive spine surgery for localization, especially for guidance in instrumentation placement. In addition, computer navigation is not accessible in some facility-limited institutions. This study aimed to demonstrate a method for percutaneous screws placement using only the anterior-posterior (AP) trajectory of intraoperative fluoroscopy. A technical report (a retrospective and prospective case series) was carried out. Patients who received posterior fixation with percutaneous pedicle screws for thoracolumbar degenerative disease or trauma comprised the patient sample. We retrospectively reviewed the charts of consecutive 670 patients who received 4,072 pedicle screws between December 2010 and August 2015. Another case series study was conducted prospectively in three additional hospitals, and 88 consecutive patients with 413 pedicle screws were enrolled from February 2014 to July 2016. The fluoroscopy shot number and radiation dose were recorded. In the prospective study, 78 patients with 371 screws received computed tomography at 3 months postoperatively to evaluate the fusion condition and screw positions. In the retrospective series, the placement of a percutaneous screw required 5.1 shots (2-14, standard deviation [SD]=2.366) of AP fluoroscopy. One screw was revised because of a medialwall breach of the pedicle. In the prospective series, 5.8 shots (2-16, SD=2.669) were required forone percutaneous pedicle screw placement. There were two screws with a Grade 1 breach (8.6%), both at the lateral wall of the pedicle, out of 23 screws placed at the thoracic spine at T9-T12. Forthe lumbar and sacral areas, there were 15 Grade 1 breaches (4.3%), 1 Grade 2 breach (0.3%), and 1 Grade 3 breach (0.3%). No revision surgery was necessary. This method avoids lateral shots of fluoroscopy during screw placement and thus decreases the operation time and exposes surgeons to less radiation. At the same time, compared with the computer-navigated procedure, it is less facility-demanding, and provides satisfactory reliability and accuracy. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Comprehensive assessment of patient image quality and radiation dose in latest generation cardiac x-ray equipment for percutaneous coronary interventions

PubMed Central

Gislason-Lee, Amber J.; Keeble, Claire; Egleston, Daniel; Bexon, Josephine; Kengyelics, Stephen M.; Davies, Andrew G.

2017-01-01

Abstract. This study aimed to determine whether a reduction in radiation dose was found for percutaneous coronary interventional (PCI) patients using a cardiac interventional x-ray system with state-of-the-art image enhancement and x-ray optimization, compared to the current generation x-ray system, and to determine the corresponding impact on clinical image quality. Patient procedure dose area product (DAP) and fluoroscopy duration of 131 PCI patient cases from each x-ray system were compared using a Wilcoxon test on median values. Significant reductions in patient dose (p≪0.001) were found for the new system with no significant change in fluoroscopy duration (p=0.2); procedure DAP reduced by 64%, fluoroscopy DAP by 51%, and “cine” acquisition DAP by 76%. The image quality of 15 patient angiograms from each x-ray system (30 total) was scored by 75 clinical professionals on a continuous scale for the ability to determine the presence and severity of stenotic lesions; image quality scores were analyzed using a two-sample t-test. Image quality was reduced by 9% (p≪0.01) for the new x-ray system. This demonstrates a substantial reduction in patient dose, from acquisition more than fluoroscopy imaging, with slightly reduced image quality, for the new x-ray system compared to the current generation system. PMID:28491907

CT Fluoroscopy Shielding: Decreases in Scattered Radiation for the Patient and Operator

PubMed Central

Neeman, Ziv; Dromi, Sergio A.; Sarin, Shawn; Wood, Bradford J.

2008-01-01

PURPOSE High-radiation exposure occurs during computed tomographic (CT) fluoroscopy. Patient and operator doses during thoracic and abdominal interventional procedures were studied in the present experiment, and a novel shielding device to reduce exposure to the patient and operator was evaluated. MATERIALS AND METHODS With a 16-slice CT scanner in CT fluoroscopy mode (120 kVp, 30 mA), surface dosimetry was performed on adult and pediatric phantoms. The shielding was composed of tungsten antimony in the form of a lightweight polymer sheet. Doses to the patient were measured with and without shielding for thoracic and abdominal procedures. Doses to the operator were recorded with and without phantom, gantry, and table shielding in place. Double-layer lead-free gloves were used by the operator during the procedures. RESULTS Tungsten antimony shielding adjacent to the scan plane resulted in a maximum dose reduction of 92.3% to the patient. Maximum 85.6%, 93.3%, and 85.1% dose reductions were observed for the operator’s torso, gonads, and hands, respectively. The use of double-layer lead-free gloves resulted in a maximum radiation dose reduction of 97%. CONCLUSIONS Methods to reduce exposure during CT fluoroscopy are effective and should be searched for. Significant reduction in radiation doses to the patient and operator can be accomplished with tungsten antimony shielding. PMID:17185699

SU-E-I-56: Diagnostic Lead Apron Radiation Exposure Comparison Between Manufacture-Stated and Measurements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Syh, J; Patel, B; Syh, J

2015-06-15

Purpose: Several vendors of diagnostic lead apron used routinely in radiology/fluoroscopy claim to manufacture 0.5 mm lead equivalent shielding. The purpose of this investigation was to address the concern of the weight of lead aprons versus the radiation protection they provide. Methods: Seven diagnostic lead aprons were measured and compared for their radiation transmission and attenuation characteristics. The measurements were performed on a Philips Integris. Two settings were used, normal (76 kVp, 14.3 mA) and high (110 kVp, 12.3 mA) to represent typical patient and large patient thickness. Plastic water was placed on the table to represent patient scatter. Amore » Capintec PM-500 ion chamber was placed at approximate chest height where hospital personnel would stand. An uncovered, i.e. lead-unhindered, ion chamber reading was taken to establish the baseline reading of an unprotected personnel. The ion chamber was then wrapped with 0.5mm 99.9% pure Pb material to establish the measurement reading when a diagnostic lead apron attenuates as adequately as 0.5mm Pb. The lead aprons were measured one at a time with the ion chamber fully covered and enclosed within the aprons. Results: On Normal fluoroscopy setting, the 0.5mm pure Pb showed a transmission of 0.4%. No aprons showed a transmission value as low as 0.5mm Pb. The lowest transmission value measured from the aprons was 2.0%, having a 1.5% higher transmission than pure lead. On High fluoroscopy setting, the lowest apron transmission measurement was at 2.8%, which was comparable to the 0.5mm pure Pb which gave a transmission of 3.0%. Conclusion: At Normal fluoroscopy setting, the 0.5mm Pb provided an attenuation that could not be matched by any apron measured. At High fluoroscopy setting, only one apron exhibited comparable transmission values as 0.5mm pure Pb.« less

Training femoral neck screw insertion skills to surgical trainees: computer-assisted surgery versus conventional fluoroscopic technique.

PubMed

Nousiainen, Markku T; Omoto, Daniel M; Zingg, Patrick O; Weil, Yoram A; Mardam-Bey, Sami W; Eward, William C

2013-02-01

: Femoral neck fractures are among the most common orthopaedic injuries impacting the health care system. Surgical management of such fractures with cannulated screws is a commonly performed procedure. The acquisition of surgical skills necessary to perform this procedure typically involves learning on real patients with fluoroscopic guidance. This study attempts to determine if a novel computer-navigated training model improves the learning of this basic surgical skill. A multicenter, prospective, randomized, and controlled study was conducted using surgical trainees with no prior experience in surgically managing femoral neck fractures. After a training session, participants underwent a pretest by performing the surgical task (screw placement) on a simulated hip fracture using fluoroscopic guidance. Immediately after, participants were randomized into either undergoing a training session using conventional fluoroscopy or computer-based navigation. Immediate posttest, retention (4 weeks later), and transfer tests were performed. Performance during the tests was determined by radiographic analysis of hardware placement. Screw placement by trainees was ultimately equal to the level of an expert surgeon with either training technique. Participants who trained with computer navigation took fewer attempts to position hardware and used less fluoroscopy time than those trained with fluoroscopy. When those trained with fluoroscopy used computer navigation at the transfer test, less fluoroscopy time and dosage was used. The concurrent augmented feedback provided by computer navigation did not affect the learning of this basic surgical skill in surgical novices. No compromise in learning occurred if the surgical novice trained with one type of technology and transferred to using the other. The findings of this study suggest that computer navigation may be safely used to train surgical novices in a basic procedure. This model avoids using both live patients and harmful radiation without a compromise in the acquisition of a 3-dimensional technical skill.

Zero-fluoroscopy cryothermal ablation of atrioventricular nodal re-entry tachycardia guided by endovascular and endocardial catheter visualization using intracardiac echocardiography (Ice&ICE Trial).

PubMed

Luani, Blerim; Zrenner, Bernhard; Basho, Maksim; Genz, Conrad; Rauwolf, Thomas; Tanev, Ivan; Schmeisser, Alexander; Braun-Dullaeus, Rüdiger C

2018-01-01

Stochastic damage of the ionizing radiation to both patients and medical staff is a drawback of fluoroscopic guidance during catheter ablation of cardiac arrhythmias. Therefore, emerging zero-fluoroscopy catheter-guidance techniques are of great interest. We investigated, in a prospective pilot study, the feasibility and safety of the cryothermal (CA) slow-pathway ablation in patients with symptomatic atrioventricular-nodal-re-entry-tachycardia (AVNRT) using solely intracardiac echocardiography (ICE) for endovascular and endocardial catheter visualization. Twenty-five consecutive patients (mean age 55.6 ± 12.0 years, 17 female) with ECG-documentation or symptoms suggesting AVNRT underwent an electrophysiology study (EPS) in our laboratory utilizing ICE for catheter navigation. Supraventricular tachycardia was inducible in 23 (92%) patients; AVNRT was confirmed by appropriate stimulation maneuvers in 20 (80%) patients. All EPS in the AVNRT subgroup could be accomplished without need for fluoroscopy, relying solely on ICE-guidance. CA guided by anatomical location and slow-pathway potentials was successful in all patients, median cryo-mappings = 6 (IQR:3-10), median cryo-ablations = 2 (IQR:1-3). Fluoroscopy was used to facilitate the trans-septal puncture and localization of the ablation substrate in the remaining 3 patients (one focal atrial tachycardia and two atrioventricular-re-entry-tachycardias). Mean EPS duration in the AVNRT subgroup was 99.8 ± 39.6 minutes, ICE guided catheter placement 11.9 ± 5.8 minutes, time needed for diagnostic evaluation 27.1 ± 10.8 minutes, and cryo-application duration 26.3 ± 30.8 minutes. ICE-guided zero-fluoroscopy CA in AVNRT patients is feasible and safe. Real-time visualization of the true endovascular borders and cardiac structures allow for safe catheter navigation during the ICE-guided EPS and might be an alternative to visualization technologies using geometry reconstructions. © 2017 Wiley Periodicals, Inc.

A comparison of CT-based navigation techniques for minimally invasive lumbar pedicle screw placement.

PubMed

Wood, Martin; Mannion, Richard

2011-02-01

A comparison of 2 surgical techniques. To determine the relative accuracy of minimally invasive lumbar pedicle screw placement using 2 different CT-based image-guided techniques. Three-dimensional intraoperative fluoroscopy systems have recently become available that provide the ability to use CT-quality images for navigation during image-guided minimally invasive spinal surgery. However, the cost of this equipment may negate any potential benefit in navigational accuracy. We therefore assess the accuracy of pedicle screw placement using an intraoperative 3-dimensional fluoroscope for guidance compared with a technique using preoperative CT images merged to intraoperative 2-dimensional fluoroscopy. Sixty-seven patients undergoing minimally invasive placement of lumbar pedicle screws (296 screws) using a navigated, image-guided technique were studied and the accuracy of pedicle screw placement assessed. Electromyography (EMG) monitoring of lumbar nerve roots was used in all. Group 1: 24 patients in whom a preoperative CT scan was merged with intraoperative 2-dimensional fluoroscopy images on the image-guidance system. Group 2: 43 patients using intraoperative 3-dimensional fluoroscopy images as the source for the image guidance system. The frequencies of pedicle breach and EMG warnings (indicating potentially unsafe screw placement) in each group were recorded. The rate of pedicle screw misplacement was 6.4% in group 1 vs 1.6% in group 2 (P=0.03). There were no cases of neurologic injury from suboptimal placement of screws. Additionally, the incidence of EMG warnings was significantly lower in group 2 (3.7% vs. 10% (P=0.03). The use of an intraoperative 3-dimensional fluoroscopy system with an image-guidance system results in greater accuracy of pedicle screw placement than the use of preoperative CT scans, although potentially dangerous placement of pedicle screws can be prevented by the use of EMG monitoring of lumbar nerve roots.

Fluoroscopic evaluation of diaphragmatic motion reduction with a respiratory gated radiotherapy system.

PubMed

Mageras, G S; Yorke, E; Rosenzweig, K; Braban, L; Keatley, E; Ford, E; Leibel, S A; Ling, C C

2001-01-01

We report on initial patient studies to evaluate the performance of a commercial respiratory gating radiotherapy system. The system uses a breathing monitor, consisting of a video camera and passive infrared reflective markers placed on the patient's thorax, to synchronize radiation from a linear accelerator with the patient's breathing cycle. Six patients receiving treatment for lung cancer participated in a study of system characteristics during treatment simulation with fluoroscopy. Breathing synchronized fluoroscopy was performed initially without instruction, followed by fluoroscopy with recorded verbal instruction (i.e., when to inhale and exhale) with the tempo matched to the patient's normal breathing period. Patients tended to inhale more consistently when given instruction, as assessed by an external marker movement. This resulted in smaller variation in expiration and inspiration marker positions relative to total excursion, thereby permitting more precise gating tolerances at those parts of the breathing cycle. Breathing instruction also reduced the fraction of session times having irregular breathing as measured by the system software, thereby potentially increasing the accelerator duty factor and decreasing treatment times. Fluoroscopy studies showed external monitor movement to correlate well with that of the diaphragm in four patients, whereas time delays of up to 0.7 s in diaphragm movement were observed in two patients with impaired lung function. From fluoroscopic observations, average patient diaphragm excursion was reduced from 1.4 cm (range 0.7-2.1 cm) without gating and without breathing instruction, to 0.3 cm (range 0.2-0.5 cm) with instruction and with gating tolerances set for treatment at expiration for 25% of the breathing cycle. Patients expressed no difficulty with following instruction for the duration of a session. We conclude that the external monitor accurately predicts internal respiratory motion in most cases; however, it may be important to check with fluoroscopy for possible time delays in patients with impaired lung function. Furthermore, we observe that verbal instruction can improve breathing regularity, thus improving the performance of gated treatments with this system.

Magnetic navigation system for percutaneous coronary intervention

PubMed Central

Qi, Zhiyong; Wu, Bangwei; Luo, Xinping; Zhu, Jun; Shi, Haiming; Jin, Bo

2016-01-01

Abstract Background: Magnetic navigation system (MNS) allows calculation of the vessel coordinates in real space within the patient's chest for percutaneous coronary intervention (PCI). However, its impact on the procedural parameters and clinical outcomes is still a matter of debate. To derive a more precise estimation of the relationship, a meta-analysis was performed. Methods and Results: Studies exploring the advantages of MNS were identified in English-language articles by search of Medline, Web of Science, and Cochrane Library Databases (inception to October 2015). A standardized protocol was used to extract details on study design, region origin, demographic data, lesion type, and clinical outcomes. The main outcome measures were contrast consumption, procedural success rate, contrast used for wire crossing, procedure time to cross the lesions, and the fluoroscopy time fluoroscopy time. A total of 12 clinical trials involving 2174 patients were included for analysis (902 patients in the magnetic PCI group and 1272 in the conventional PCI group). Overall, contrast consumption was decreased by 40.45 mL (95% confidence interval [CI] −70.98 to −9.92, P = 0.009) in magnetic PCI group compared with control group. In addition, magnetic PCI was associated with significantly decreasing procedural time by 2.17 minutes (95% CI −3.91 to −0.44, P = 0.01) and the total fluoroscopy time was significantly decreased by 1.43 minutes (95% CI −2.29 to −0.57, P = 0.001) in magnetic PCI group. However, procedural success rate, contrast used for wire crossing, procedure time to cross the lesions, and the fluoroscopy time to cross the lesions demonstrated that no statistically difference was observed between 2 groups. Conclusion: The present meta-analysis indicated an improvement of overall contrast consumption, total procedural time, and fluoroscopy time in magnetic PCI group. However, no significant advantages were observed associated with procedural success rate. PMID:27442645

Magnetic navigation system for percutaneous coronary intervention: A meta-analysis.

PubMed

Qi, Zhiyong; Wu, Bangwei; Luo, Xinping; Zhu, Jun; Shi, Haiming; Jin, Bo

2016-07-01

Magnetic navigation system (MNS) allows calculation of the vessel coordinates in real space within the patient's chest for percutaneous coronary intervention (PCI). However, its impact on the procedural parameters and clinical outcomes is still a matter of debate. To derive a more precise estimation of the relationship, a meta-analysis was performed. Studies exploring the advantages of MNS were identified in English-language articles by search of Medline, Web of Science, and Cochrane Library Databases (inception to October 2015). A standardized protocol was used to extract details on study design, region origin, demographic data, lesion type, and clinical outcomes. The main outcome measures were contrast consumption, procedural success rate, contrast used for wire crossing, procedure time to cross the lesions, and the fluoroscopy time fluoroscopy time. A total of 12 clinical trials involving 2174 patients were included for analysis (902 patients in the magnetic PCI group and 1272 in the conventional PCI group). Overall, contrast consumption was decreased by 40.45 mL (95% confidence interval [CI] -70.98 to -9.92, P = 0.009) in magnetic PCI group compared with control group. In addition, magnetic PCI was associated with significantly decreasing procedural time by 2.17 minutes (95% CI -3.91 to -0.44, P = 0.01) and the total fluoroscopy time was significantly decreased by 1.43 minutes (95% CI -2.29 to -0.57, P = 0.001) in magnetic PCI group. However, procedural success rate, contrast used for wire crossing, procedure time to cross the lesions, and the fluoroscopy time to cross the lesions demonstrated that no statistically difference was observed between 2 groups. The present meta-analysis indicated an improvement of overall contrast consumption, total procedural time, and fluoroscopy time in magnetic PCI group. However, no significant advantages were observed associated with procedural success rate.

Evaluation of an X-Ray Dose Profile Derived from an Optically Stimulated Luminescent Dosimeter during Computed Tomographic Fluoroscopy.

PubMed

Hasegawa, Hiroaki; Sato, Masanori; Tanaka, Hiroshi

2015-01-01

The purpose of this study was to evaluate scatter radiation dose to the subject surface during X-ray computed tomography (CT) fluoroscopy using the integrated dose ratio (IDR) of an X-ray dose profile derived from an optically stimulated luminescent (OSL) dosimeter. We aimed to obtain quantitative evidence supporting the radiation protection methods used during previous CT fluoroscopy. A multislice CT scanner was used to perform this study. OSL dosimeters were placed on the top and the lateral side of the chest phantom so that the longitudinal direction of dosimeters was parallel to the orthogonal axis-to-slice plane for measurement of dose profiles in CT fluoroscopy. Measurement of fluoroscopic conditions was performed at 120 kVp and 80 kVp. Scatter radiation dose was evaluated by calculating the integrated dose determined by OSL dosimetry. The overall percent difference of the integrated doses between OSL dosimeters and ionization chamber was 5.92%. The ratio of the integrated dose of a 100-mm length area to its tails (-50 to -6 mm, 50 to 6 mm) was the lowest on the lateral side at 80 kVp and the highest on the top at 120 kVp. The IDRs for different measurement positions were larger at 120 kVp than at 80 kVp. Similarly, the IDRs for the tube voltage between the primary X-ray beam and scatter radiation was larger on the lateral side than on the top of the phantom. IDR evaluation suggested that the scatter radiation dose has a high dependence on the position and a low dependence on tube voltage relative to the primary X-ray beam for constant dose rate fluoroscopic conditions. These results provided quantitative evidence supporting the radiation protection methods used during CT fluoroscopy in previous studies.

Evaluation of an X-Ray Dose Profile Derived from an Optically Stimulated Luminescent Dosimeter during Computed Tomographic Fluoroscopy

PubMed Central

Hasegawa, Hiroaki; Sato, Masanori; Tanaka, Hiroshi

2015-01-01

The purpose of this study was to evaluate scatter radiation dose to the subject surface during X-ray computed tomography (CT) fluoroscopy using the integrated dose ratio (IDR) of an X-ray dose profile derived from an optically stimulated luminescent (OSL) dosimeter. We aimed to obtain quantitative evidence supporting the radiation protection methods used during previous CT fluoroscopy. A multislice CT scanner was used to perform this study. OSL dosimeters were placed on the top and the lateral side of the chest phantom so that the longitudinal direction of dosimeters was parallel to the orthogonal axis-to-slice plane for measurement of dose profiles in CT fluoroscopy. Measurement of fluoroscopic conditions was performed at 120 kVp and 80 kVp. Scatter radiation dose was evaluated by calculating the integrated dose determined by OSL dosimetry. The overall percent difference of the integrated doses between OSL dosimeters and ionization chamber was 5.92%. The ratio of the integrated dose of a 100-mm length area to its tails (−50 to −6 mm, 50 to 6 mm) was the lowest on the lateral side at 80 kVp and the highest on the top at 120 kVp. The IDRs for different measurement positions were larger at 120 kVp than at 80 kVp. Similarly, the IDRs for the tube voltage between the primary X-ray beam and scatter radiation was larger on the lateral side than on the top of the phantom. IDR evaluation suggested that the scatter radiation dose has a high dependence on the position and a low dependence on tube voltage relative to the primary X-ray beam for constant dose rate fluoroscopic conditions. These results provided quantitative evidence supporting the radiation protection methods used during CT fluoroscopy in previous studies. PMID:26151914

The fluoroscopy time, door to balloon time, contrast volume use and prevalence of vascular access site failure with transradial versus transfemoral approach in ST segment elevation myocardial infarction: A systematic review & meta-analysis.

PubMed

Singh, Sukhchain; Singh, Mukesh; Grewal, Navsheen; Khosla, Sandeep

2015-12-01

The authors aimed to conduct first systematic review and meta-analysis in STEMI patients evaluating vascular access site failure rate, fluoroscopy time, door to balloon time and contrast volume used with transradial vs transfemoral approach (TRA vs TFA) for PCI. The PubMed, CINAHL, clinicaltrials.gov, Embase and CENTRAL databases were searched for randomized trials comparing TRA versus TFA. Random effect models were used to conduct this meta-analysis. Fourteen randomized trials comprising 3758 patients met inclusion criteria. The access site failure rate was significantly higher TRA compared to TFA (RR 3.30, CI 2.16-5.03; P=0.000). Random effect inverse variance weighted prevalence rate meta-analysis showed that access site failure rate was predicted to be 4% (95% CI 3.0-6.0%) with TRA versus 1% (95% CI 0.0-1.0 %) with TFA. Door to balloon time (Standardized mean difference [SMD] 0.30 min, 95% CI 0.23-0.37 min; P=0.000) and fluoroscopy time (Standardized mean difference 0.14 min, 95% CI 0.06-0.23 min; P=0.001) were also significantly higher in TRA. There was no difference in the amount of contrast volume used with TRA versus TFA (SMD -0.05 ml, 95% CI -0.14 to 0.04 ml; P=0.275). Statistical heterogeneity was low in cross-over rate and contrast volume use, moderate in fluoroscopy time but high in the door to balloon time comparison. Operators need to consider higher cross-over rate with TRA compared to TFA in STEMI patients while attempting PCI. Fluoroscopy and door to balloon times are negligibly higher with TRA but there is no difference in terms of contrast volume use. Copyright © 2015 Elsevier Inc. All rights reserved.

The AAPM/RSNA physics tutorial for residents: digital fluoroscopy.

PubMed

Pooley, R A; McKinney, J M; Miller, D A

2001-01-01

A digital fluoroscopy system is most commonly configured as a conventional fluoroscopy system (tube, table, image intensifier, video system) in which the analog video signal is converted to and stored as digital data. Other methods of acquiring the digital data (eg, digital or charge-coupled device video and flat-panel detectors) will become more prevalent in the future. Fundamental concepts related to digital imaging in general include binary numbers, pixels, and gray levels. Digital image data allow the convenient use of several image processing techniques including last image hold, gray-scale processing, temporal frame averaging, and edge enhancement. Real-time subtraction of digital fluoroscopic images after injection of contrast material has led to widespread use of digital subtraction angiography (DSA). Additional image processing techniques used with DSA include road mapping, image fade, mask pixel shift, frame summation, and vessel size measurement. Peripheral angiography performed with an automatic moving table allows imaging of the peripheral vasculature with a single contrast material injection.

A novel technique for ventriculoperitoneal shunting by flat panel detector CT-guided real-time fluoroscopy

PubMed Central

Kobayashi, Shinya; Ishikawa, Tatsuya; Mutoh, Tatsushi; Hikichi, Kentaro; Suzuki, Akifumi

2012-01-01

Background: Surgical placement of a ventriculoperitoneal shunt (VPS) is the main strategy to manage hydrocephalus. However, the failure rate associated with placement of ventricular catheters remains high. Methods: A hybrid operating room, equipped with a flat-panel detector digital subtraction angiography system containing C-arm cone-beam computed tomography (CB-CT) imaging, has recently been developed and utilized to assist neurosurgical procedures. We have developed a novel technique using intraoperative fluoroscopy and a C-arm CB-CT system to facilitate accurate placement of a VPS. Results: Using this novel technique, 39 consecutive ventricular catheters were placed accurately, and no ventricular catheter failures were experienced during the follow-up period. Only two patients experienced obstruction of the VPS, both of which occurred in the extracranial portion of the shunt system. Conclusion: Surgical placement of a VPS assisted by flat panel detector CT-guided real-time fluoroscopy enabled accurate placement of ventricular catheters and was associated with a decreased need for shunt revision. PMID:23226605

Towards image-guided atrial septal defect repair: an ex vivo analysis

NASA Astrophysics Data System (ADS)

Kwartowitz, David M.; Mefleh, Fuad N.; Baker, George H.

2012-02-01

The use of medical images in the operating room for navigation and planning is well established in many clinical disciplines. In cardiology, the use of fluoroscopy for the placement of catheters within the heart has become the standard of care. While fluoroscopy provides a live video sequence with the current location, it poses risks the patient and clinician through exposure to radiation. Radiation dose is cumulative and thus children are at even greater risk from exposure. To reduce the use of radiation, and improve surgical technique we have begun development of an image-guided navigation system, which can deliver therapeutic devices via catheter. In this work we have demonstrated the intrinsic properties of our imaging system, which have led to the development of a phantom emulating a childs heart with an ASD. Further investigation into the use of this information, in a series of mock clinical experiments, will be performed to design procedures for inserting devices into the heart while minimizing fluoroscopy use.

Update on the recommended viewing protocol for FAXIL threshold contrast detail detectability test objects used in television fluoroscopy.

PubMed

Launders, J H; McArdle, S; Workman, A; Cowen, A R

1995-01-01

The significance of varying the viewing conditions that may affect the perceived threshold contrast of X-ray television fluoroscopy systems has been investigated. Factors investigated include the ambient room lighting and the viewing distance. The purpose of this study is to find the optimum viewing protocol with which to measure the threshold detection index. This is a particular problem when trying to compare the image quality of television fluoroscopy systems in different input field sizes. The results show that the viewing distance makes a significant difference to the perceived threshold contrast, whereas the ambient light conditions make no significant difference. Experienced observers were found to be capable of finding the optimum viewing distance for detecting details of each size, in effect using a flexible viewing distance. This allows the results from different field sizes to be normalized to account for both the magnification and the entrance air kerma rate differences, which in turn allow for a direct comparison of performance in different field sizes.

Combined hysteroscopy-laparoscopy approach for excision of pelvic nitinol fragment from Essure contraceptive device: Role of intraoperative fluoroscopy for uterine conservation

PubMed Central

Palermo, Gianpiero D.

2016-01-01

We describe the successful removal of a pelvic contraceptive coil in a symptomatic 46-year-old patient who had Essure devices for four years, using a combined hysteroscopy-laparoscopy-fluoroscopy approach. Following normal hysteroscopy, at laparoscopy the right Essure implant was disrupted and its outer nitinol coil had perforated the fallopian tube. However, the inner rod (containing polyethylene terephthalate) had migrated to an extrapelvic location, near the proximal colon. In contrast, the left implant was situated within the corresponding tube. Intraoperative fluoroscopy was used to confirm complete removal of the device, which was further verified by postoperative computed tomography. The patient's condition improved after surgery and she continues to do well. This is the first report to describe this technique in managing Essure complications remote from time of insertion. Our case highlights the value and limitations of preoperative and intraoperative imaging to map Essure fragment location before surgery. PMID:27462605

[Evaluation of an Experimental Production Wireless Dose Monitoring System for Radiation Exposure Management of Medical Staff].

PubMed

Fujibuchi, Toshioh; Murazaki, Hiroo; Kuramoto, Taku; Umedzu, Yoshiyuki; Ishigaki, Yung

2015-08-01

Because of the more advanced and more complex procedures in interventional radiology, longer treatment times have become necessary. Therefore, it is important to determine the exposure doses received by operators and patients. The aim of our study was to evaluate an experimental production wireless dose monitoring system for pulse radiation in diagnostic X-ray. The energy, dose rate, and pulse fluoroscopy dependence were evaluated as the basic characteristics of this system for diagnostic X-ray using a fully digital fluoroscopy system. The error of 1 cm dose equivalent rate was less than 15% from 35.1 keV to 43.2 keV with energy correction using metal filter. It was possible to accurately measure the dose rate dependence of this system, which was highly linear until 100 μSv/h. This system showed a constant response to the pulse fluoroscopy. This system will become useful wireless dosimeter for the individual exposure management by improving the high dose rate and the energy characteristics.

Fluoroscopy guided percutaneous renal access in prone position

PubMed Central

Sharma, Gyanendra R; Maheshwari, Pankaj N; Sharma, Anshu G; Maheshwari, Reeta P; Heda, Ritwik S; Maheshwari, Sakshi P

2015-01-01

Percutaneous nephrolithotomy is a very commonly done procedure for management of renal calculus disease. Establishing a good access is the first and probably the most crucial step of this procedure. A proper access is the gateway to success. However, this crucial step has the steepest learning curve for, in a fluoroscopy guided access, it involves visualizing a three dimensional anatomy on a two dimensional fluoroscopy screen. This review describes the anatomical basis of the renal access. It provides a literature review of all aspects of percutaneous renal access along with the advances that have taken place in this field over the years. The article describes a technique to determine the site of skin puncture, the angle and depth of puncture using a simple mathematical principle. It also reviews the common problems faced during the process of puncture and dilatation and describes the ways to overcome them. The aim of this article is to provide the reader a step by step guide for percutaneous renal access. PMID:25789297

Real-Time 3D Fluoroscopy-Guided Large Core Needle Biopsy of Renal Masses: A Critical Early Evaluation According to the IDEAL Recommendations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kroeze, Stephanie G. C.; Huisman, Merel; Verkooijen, Helena M.

2012-06-15

Introduction: Three-dimensional (3D) real-time fluoroscopy cone beam CT is a promising new technique for image-guided biopsy of solid tumors. We evaluated the technical feasibility, diagnostic accuracy, and complications of this technique for guidance of large-core needle biopsy in patients with suspicious renal masses. Methods: Thirteen patients with 13 suspicious renal masses underwent large-core needle biopsy under 3D real-time fluoroscopy cone beam CT guidance. Imaging acquisition and subsequent 3D reconstruction was done by a mobile flat-panel detector (FD) C-arm system to plan the needle path. Large-core needle biopsies were taken by the interventional radiologist. Technical success, accuracy, and safety were evaluatedmore » according to the Innovation, Development, Exploration, Assessment, Long-term study (IDEAL) recommendations. Results: Median tumor size was 2.6 (range, 1.0-14.0) cm. In ten (77%) patients, the histological diagnosis corresponded to the imaging findings: five were malignancies, five benign lesions. Technical feasibility was 77% (10/13); in three patients biopsy results were inconclusive. The lesion size of these three patients was <2.5 cm. One patient developed a minor complication. Median follow-up was 16.0 (range, 6.4-19.8) months. Conclusions: 3D real-time fluoroscopy cone beam CT-guided biopsy of renal masses is feasible and safe. However, these first results suggest that diagnostic accuracy may be limited in patients with renal masses <2.5 cm.« less

CT fluoroscopy-guided preoperative short hook wire placement for small pulmonary lesions: evaluation of safety and identification of risk factors for pneumothorax.

PubMed

Iguchi, Toshihiro; Hiraki, Takao; Gobara, Hideo; Fujiwara, Hiroyasu; Matsui, Yusuke; Miyoshi, Shinichiro; Kanazawa, Susumu

2016-01-01

To retrospectively evaluate the safety of computed tomography (CT) fluoroscopy-guided short hook wire placement for video-assisted thoracoscopic surgery and the risk factors for pneumothorax associated with this procedure. We analyzed 267 short hook wire placements for 267 pulmonary lesions (mean diameter, 9.9 mm). Multiple variables related to the patients, lesions, and procedures were assessed to determine the risk factors for pneumothorax. Complications (219 grade 1 and 4 grade 2 adverse events) occurred in 196 procedures. No grade 3 or above adverse events were observed. Univariate analysis revealed increased vital capacity (odds ratio [OR], 1.518; P = 0.021), lower lobe lesion (OR, 2.343; P =0.001), solid lesion (OR, 1.845; P = 0.014), prone positioning (OR, 1.793; P = 0.021), transfissural approach (OR, 11.941; P = 0.017), and longer procedure time (OR, 1.036; P = 0.038) were significant predictors of pneumothorax. Multivariate analysis revealed only the transfissural approach (OR, 12.171; P = 0.018) and a longer procedure time (OR, 1.048; P = 0.012) as significant independent predictors. Complications related to CT fluoroscopy-guided preoperative short hook wire placement often occurred, but all complications were minor. A transfissural approach and longer procedure time were significant independent predictors of pneumothorax. Complications related to CT fluoroscopy-guided preoperative short hook wire placement often occur. Complications are usually minor and asymptomatic. A transfissural approach and longer procedure time are significant independent predictors of pneumothorax.

Perioperative versus postoperative measurement of Taylor Spatial Frame mounting parameters.

PubMed

Sökücü, Sami; Demir, Bilal; Lapçin, Osman; Yavuz, Umut; Kabukçuoğlu, Yavuz S

2014-01-01

The aim of this study was to determine the differences, if any, between application parameters for the Taylor Spatial Frame (TSF) system obtained during surgery under fluoroscopy and after surgery from digital radiography. This retrospective study included 17 extremities of 15 patients (8 male, 7 female; mean age: 21.9 years, range: 10 to 55 years) who underwent TSF after deformity and fracture. Application parameters measured by fluoroscopy at the end of surgery after mounting the fixator were compared with parameters obtained from anteroposterior and lateral digital radiographs taken 1 day after surgery. Fixator was applied to the femur in 8 patients, tibia in 6 and radius in 3. Mean time to removal of the frame was 3.5 (range: 3 to 7) months. Mean perioperative anteroposterior, lateral and axial frame offsets of patients were 9.1 (range: 3 to 20) mm, 18.1 (range: 5 to 37) mm and 95.3 (range: 25 to 155) mm, respectively. Mean postoperative anteroposterior, lateral and axial frame offset radiographs were 11.8 (range: 2 to 30) mm, 18 (range: 6 to 47) mm and 109.5 (range: 28 to 195) mm, respectively. There was no statistically significant difference between the groups (p>0.05). While measurements taken during operation may lengthen the duration in the operation room, fluoroscopy may provide better images and is easier to perform than digital radiography. On the other hand, there is no difference between measurements taken during perioperative fluoroscopy and postoperative digital radiography.

Biplanar x-ray fluoroscopy for sacroiliac joint fusion.

PubMed

Vanaclocha-Vanaclocha, Vicente; Verdú-López, Francisco; Sáiz-Sapena, Nieves; Herrera, Juan Manuel; Rivera-Paz, Marlon

2016-07-01

Chronic pain originating from the sacroiliac joint (SI) can cause severe dysfunction. Although many patients respond to conservative management with NSAIDs, some do need further treatment in the form of SI joint fusion (SIJF). To achieve safe and successful SIJF, intraoperative x-ray fluoroscopy is mandatory to avoid serious damages to nearby vascular and neural structures. Each step of the procedure has to be confirmed by anteroposterior (AP) and lateral projections. With a single-arm x-ray, the arch has to be moved back and forth for the AP and lateral projections, and this lengthens the procedure. To achieve the same results in less time, the authors introduced simultaneous biplanar fluoroscopy with 2 x-ray arches. After the patient is positioned prone with the legs spread apart in the so-called Da Vinci position, one x-ray arch for the lateral projection is placed at a right angle to the patient, and a second x-ray machine is placed with its arch between the legs of the patient. This allows simultaneous AP and lateral x-ray projections and, in the authors' hands, markedly speeds up the procedure. Biplanar fluoroscopy allows excellent AP and lateral projections to be made quickly at any time during the surgical procedure. This is particularly useful in cases of bilateral SI joint fusion if both sides are done at the same time. The video can be found here: https://youtu.be/TX5gz8c765M .

Real-time fusion of coronary CT angiography with x-ray fluoroscopy during chronic total occlusion PCI.

PubMed

Ghoshhajra, Brian B; Takx, Richard A P; Stone, Luke L; Girard, Erin E; Brilakis, Emmanouil S; Lombardi, William L; Yeh, Robert W; Jaffer, Farouc A

2017-06-01

The purpose of this study was to demonstrate the feasibility of real-time fusion of coronary computed tomography angiography (CTA) centreline and arterial wall calcification with x-ray fluoroscopy during chronic total occlusion (CTO) percutaneous coronary intervention (PCI). Patients undergoing CTO PCI were prospectively enrolled. Pre-procedural CT scans were integrated with conventional coronary fluoroscopy using prototype software. We enrolled 24 patients who underwent CTO PCI using the prototype CT fusion software, and 24 consecutive CTO PCI patients without CT guidance served as a control group. Mean age was 66 ± 11 years, and 43/48 patients were men. Real-time CTA fusion during CTO PCI provided additional information regarding coronary arterial calcification and tortuosity that generated new insights into antegrade wiring, antegrade dissection/reentry, and retrograde wiring during CTO PCI. Overall CTO success rates and procedural outcomes remained similar between the two groups, despite a trend toward higher complexity in the fusion CTA group. This study demonstrates that real-time automated co-registration of coronary CTA centreline and calcification onto live fluoroscopic images is feasible and provides new insights into CTO PCI, and in particular, antegrade dissection reentry-based CTO PCI. • Real-time semi-automated fusion of CTA/fluoroscopy is feasible during CTO PCI. • CTA fusion data can be toggled on/off as desired during CTO PCI • Real-time CT calcium and centreline overlay could benefit antegrade dissection/reentry-based CTO PCI.

Percutaneous computer-assisted translaminar facet screw: an initial human cadaveric study.

PubMed

Sasso, Rick C; Best, Natalie M; Potts, Eric A

2005-01-01

Translaminar facet screws are a minimally invasive technique for posterior lumbar fixation with good success rates. Computer-assisted image navigation using virtual fluoroscopy allows multiple simultaneous screens in various planes to plan and drive spinal instrumentation. This study evaluates the percutaneous placement of translaminar facet screws with the use of virtual fluoroscopy as an image guidance technique. A human cadaveric study was performed with a percutaneous reference frame applied to the iliac crest. Ten translaminar facet screws were placed bilaterally at five levels. Anteroposterior and lateral images were used to navigate 4.0-mm screws through a percutaneous portal under virtual fluoroscopy. An axial computed tomographic scan through the instrumented levels was obtained after the screws were placed. Screws were graded on entry, course through the lamina, and terminus. A grading system was devised to grade the course through the lamina. All 10 screw-entry points were judged optimal at the spinous process laminar junction. There were five Grade I breeches with less than 1/2 the screw through the lamina, and five Grade 0 screw placements with the screw contained completely within the lamina. The termination point was acceptable in five screws. The screws that began on the right and terminated on the left were all found to have grade II breakouts. No screws placed the spinal canal or exiting nerve root at risk. Virtual fluoroscopy provides significant assistance in percutaneous placement of translaminar facet screws and results in safe position of entry, lamina course, and terminus.

Fluoroscopic study of the normal gastrointestinal motility and measurements in the Hispaniolan Amazon parrot (Amazona ventralis).

PubMed

Beaufrère, Hugues; Nevarez, Javier; Taylor, W Michael; Jankowski, Gwendolyn; Rademacher, Nathalie; Gaschen, Lorrie; Pariaut, Romain; Tully, Thomas N

2010-01-01

Contrast fluoroscopy is a valuable tool to examine avian gastrointestinal motility. However, the lack of a standardized examination protocol and reference ranges prevents the objective interpretation of motility disorders and other gastrointestinal abnormalities. Our goals were to evaluate gastrointestinal motility in 20 Hispaniolan Amazon parrots (Amazona ventralis) by contrast fluoroscopy. Each parrot was crop-fed an equal part mixture of barium sulfate and hand-feeding formula and placed in a cardboard box for fluoroscopy. Over a 3-h period, 1.5 minute segments of lateral and ventrodorsal fluoroscopy were recorded every 30 min. The gastric cycle and patterns of intestinal motility were described. The frequency of crop contractions, esophageal boluses, and gastric cycles were determined in lateral and ventrodorsal views. A range of 3.4-6.6 gastric cycles/min was noted on the lateral view and 3.0-6.6 gastric cycles/min on the ventrodorsal view. Circular measurements of the proventriculus diameter, ventriculus width, and length were obtained using the midshaft femoral diameter as a standard reference unit. The upper limits of the reference ranges were 3.6 and 4.7 femoral units for the proventriculus diameter in the lateral and ventrodorsal view, respectively. Two consecutive measurements were obtained and the measurement technique was found to have high reproducibility. In this study, we established a standardized protocol for contrast fluoroscopic examination of the gastrointestinal tract and a reliable measurement method of the proventriculus and ventriculus using femoral units in the Hispaniolan Amazon parrot.

A Modified Personalized Image-Based Drill Guide Template for Atlantoaxial Pedicle Screw Placement: A Clinical Study

PubMed Central

Jiang, Lianghai; Dong, Liang; Tan, Mingsheng; Qi, Yingna; Yang, Feng; Yi, Ping; Tang, Xiangsheng

2017-01-01

Background Atlantoaxial posterior pedicle screw fixation has been widely used for treatment of atlantoaxial instability (AAI). However, precise and safe insertion of atlantoaxial pedicle screws remains challenging. This study presents a modified drill guide template based on a previous template for atlantoaxial pedicle screw placement. Material/Methods Our study included 54 patients (34 males and 20 females) with AAI. All the patients underwent posterior atlantoaxial pedicle screw fixation: 25 patients underwent surgery with the use of a modified drill guide template (template group) and 29 patients underwent surgery via the conventional method (conventional group). In the template group, a modified drill guide template was designed for each patient. The modified drill guide template and intraoperative fluoroscopy were used for surgery in the template group, while only intraoperative fluoroscopy was used in the conventional group. Results Of the 54 patients, 52 (96.3%) completed the follow-up for more than 12 months. The template group had significantly lower intraoperative fluoroscopy frequency (p<0.001) and higher accuracy of screw insertion (p=0.045) than the conventional group. There were no significant differences in surgical duration, intraoperative blood loss, or improvement of neurological function between the 2 groups (p>0.05). Conclusions Based on the results of this study, it is feasible to use the modified drill guide template for atlantoaxial pedicle screw placement. Using the template can significantly lower the screw malposition rate and the frequency of intraoperative fluoroscopy. PMID:28301445

Radiation exposure--do urologists take it seriously in Turkey?

PubMed

Söylemez, Haluk; Altunoluk, Bülent; Bozkurt, Yaşar; Sancaktutar, Ahmet Ali; Penbegül, Necmettin; Atar, Murat

2012-04-01

A questionnaire was administered to urologists to evaluate attitudes and behaviors about protection from radiation exposure during fluoroscopy guided endourological procedures. The questionnaire was e-mailed to 1,482 urologists, including urology residents, specialists and urologists holding all levels of academic degrees, between May and June 2011. The questionnaire administered to study participants was composed of demographic questions, and questions on radiation exposure frequency, and the use of dosimeters and flexible protective clothes. If a respondent reported not using dosimeters or protective clothes, additional questions asked for the reason. Of the 1,482 questionnaires 394 (26.58%) were returned, of which 363 had completed answers. A total of 307 physicians (84.58%) were exposed to ionizing radiation, of whom 79.61% stated that they perform percutaneous nephrolithotomy at the clinic. Fluoroscopy guidance was the initial choice of 96.19% of urologists during percutaneous nephrolithotomy. Despite the common use of lead aprons (75.24%) most urologists did not use dosimeters (73.94%), eyeglasses (76.95%) or gloves (66.67%) while 46.44% always used thyroid shields during fluoroscopy. When asked why they did not use protective clothing, the most common answers were that protective clothes are not ergonomic and not practical. Results clearly highlight the lack of use of ionizing radiation protection devices and dosimeters during commonly performed fluoroscopy guided endourological procedures among urologists in Turkey. Copyright © 2012 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Bimanual, intra-operative, fluoroscopy-guided removal of nasopharyngeal migratory fish bone from carotid space.

PubMed

Al-Abduwani, J A; Bhargava, D; Sawhney, S; Al-Abri, R

2010-07-01

We report a rare and unusual case of a patient with an ingested fishbone which migrated from the oropharynx to the anterior compartment of the retropharyngeal space and then to the deep neck space in the nasopharynx (i.e. the carotid space). This report aims to describe a successful, minimally invasive method of foreign body removal which avoided both major skull base surgery and any potential life-threatening complications. A secondary aim is to highlight the role of intra-operative fluoroscopy, an under-used tool. We present a 67-year-old man with a history of fish bone impaction but no fish bone visible on plain X-ray or flexible endoscopy. The diagnosis of fish bone lodged in the retropharyngeal space was confirmed by computed tomography. Surgical exploration of the anterior retropharyngeal space failed to locate the fish bone, as it had migrated to a new, unknown location. Intra-operative fluoroscopy was vital for the removal of the fish bone, as it was impossible to see with the naked eye and had migrated from its previously imaged position. The fish bone was finally retrieved bimanually using external pressure on the submandibular region, which displaced the fish bone, and fluoroscopic guidance, which assisted its removal from the nasopharyngeal lumen. To the best of our knowledge, this is the first reported case of bimanual, intra-operative, fluoroscopy-guided, intra-luminal removal of a migratory fish bone from the deep neck space in this region of the nasopharynx.

Radiation exposure of patient and surgeon in minimally invasive kidney stone surgery.

PubMed

Demirci, A; Raif Karabacak, O; Yalçınkaya, F; Yiğitbaşı, O; Aktaş, C

2016-05-01

Percutaneous nephrolithotomy (PNL) and retrograde intrarenal surgery (RIRS) are the standard treatments used in the endoscopic treatment of kidney stones depending on the location and the size of the stone. The purpose of the study was to show the radiation exposure difference between the minimally invasive techniques by synchronously measuring the amount of radiation the patients and the surgeon received in each session, which makes our study unique. This is a prospective study which included 20 patients who underwent PNL, and 45 patients who underwent RIRS in our clinic between June 2014 and October 2014. The surgeries were assessed by dividing them into three steps: step 1: the access sheath or ureter catheter placement, step 2: lithotripsy and collection of fragments, and step 3: DJ catheter or re-entry tube insertion. For the PNL and RIRS groups, mean stone sizes were 30mm (range 16-60), and 12mm (range 7-35); mean fluoroscopy times were 337s (range 200-679), and 37s (range 7-351); and total radiation exposures were 142mBq (44.7 to 221), and 4.4mBq (0.2 to 30) respectively. Fluoroscopy times and radiation exposures at each step were found to be higher in the PNL group compared to the RIRS group. When assessed in itself, the fluoroscopy time and radiation exposure were stable in RIRS, and the radiation exposure was the highest in step 1 and the lowest in step 3 in PNL. When assessed for the 19 PNL patients and the 12 RIRS patients who had stone sizes≥2cm, the fluoroscopy time in step 1, and the radiation exposure in steps 1 and 2 were found to be higher in the PNL group than the RIRS group (P<0.001). Although there is need for more prospective randomized studies, RIRS appears to be a viable alternate for PNL because it has short fluoroscopy time and the radiation exposure is low in every step. 4. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Lightweight bilayer barium sulfate-bismuth oxide composite thyroid collars for superior radiation protection in fluoroscopy-guided interventions: a prospective randomized controlled trial.

PubMed

Uthoff, Heiko; Benenati, Matthew J; Katzen, Barry T; Peña, Constantino; Gandhi, Ripal; Staub, Daniel; Schernthaner, Melanie

2014-02-01

To test whether newer bilayer barium sulfate-bismuth oxide composite (XPF) thyroid collars (TCs) provide superior radiation protection and comfort during fluoroscopy-guided interventions compared with standard 0.5-mm lead-equivalent TCs. Institutional review board approval and written informed consent were obtained for this HIPAA-compliant study, and 144 fluoroscopy-guided vascular interventions were included at one center between October 2011 and July 2012, with up to two operators randomly assigned to wear XPF (n = 135) or standard 0.5-mm lead-equivalent (n = 121) TCs. Radiation doses were measured by using dosimeters placed outside and underneath the TCs. Wearing comfort was assessed at the end of each procedure on a visual analog scale (0-100, with 100 indicating optimal comfort). Adjusted differences in comfort and radiation dose reductions were calculated by using a mixed logistic regression model and the common method of inverse variance weighting, respectively. Patient (height, weight, and body mass index) and procedure (type and duration of intervention, operator, fluoroscopy time, dose-area product, and air kerma) data did not differ between the XPF and standard groups. Comfort was assessed in all 256 measurements. On average, the XPF TCs were 47.6% lighter than the standard TCs (mean weight ± standard deviation, 133 g ± 14 vs 254 g ± 44; P < .001) and had a significantly higher likelihood of a high level of comfort (visual analog scale >90; odds ratio, 7.6; 95% confidence interval: 3.0, 19.2; P < .001). Radiation dose reduction provided by the TCs was analyzed in 117 data sets (60 in the XPF group, 57 in the standard group). The mean radiation dose reductions (ie, radiation protection) provided by XPF and standard TCs were 90.7% and 72.4%, with an adjusted mean difference of 17.9% (95% confidence interval: 7.7%, 28.1%; P < .001) favoring XPF. XPF TCs are a lightweight alternative to standard 0.5-mm lead-equivalent TCs and provide superior radiation protection during fluoroscopy-guided interventions. © RSNA, 2013.

Uterine Artery Embolization for Leiomyomata: Optimization of the Radiation Dose to the Patient Using a Flat-Panel Detector Angiographic Suite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sapoval, Marc, E-mail: marc.sapoval2@egp.aphp.fr; Pellerin, Olivier; Rehel, Jean-Luc

The purpose of this study was to assess the ability of low-dose/low-frame fluoroscopy/angiography with a flat-panel detector angiographic suite to reduce the dose delivered to patients during uterine fibroid embolization (UFE). A two-step prospective dosimetric study was conducted, with a flat-panel detector angiography suite (Siemens Axiom Artis) integrating automatic exposure control (AEC), during 20 consecutive UFEs. Patient dosimetry was performed using calibrated thermoluminescent dosimeters placed on the lower posterior pelvis skin. The first step (10 patients; group A) consisted in UFE (bilateral embolization, calibrated microspheres) performed using the following parameters: standard fluoroscopy (15 pulses/s) and angiography (3 frames/s). The secondmore » step (next consecutive 10 patients; group B) used low-dose/low-frame fluoroscopy (7.5 pulses/s for catheterization and 3 pulses/s for embolization) and angiography (1 frame/s). We also recorded the total dose-area product (DAP) delivered to the patient and the fluoroscopy time as reported by the manufacturer's dosimetry report. The mean peak skin dose decreased from 2.4 {+-} 1.3 to 0.4 {+-} 0.3 Gy (P = 0.001) for groups A and B, respectively. The DAP values decreased from 43,113 {+-} 27,207 {mu}Gy m{sup 2} for group A to 9,515 {+-} 4,520 {mu}Gy m{sup 2} for group B (P = 0.003). The dose to ovaries and uterus decreased from 378 {+-} 238 mGy (group A) to 83 {+-} 41 mGy (group B) and from 388 {+-} 246 mGy (group A) to 85 {+-} 39 mGy (group B), respectively. Effective doses decreased from 112 {+-} 71 mSv (group A) to 24 {+-} 12 mSv (group B) (P = 0.003). In conclusion, the use of low-dose/low-frame fluoroscopy/angiography, based on a good understanding of the AEC system and also on the technique during uterine fibroid embolization, allows a significant decrease in the dose exposure to the patient.« less

Reduction of Radiation Exposure Using Dynamic Trace Digital Angiography and Spot Fluoroscopy During Adrenal Venous Sampling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morita, Satoru, E-mail: i@imodey.com; Endo, Kenji; Suzaki, Shingo

PurposeTo compare radiation exposure of adrenal venous sampling (AVS) using dynamic trace digital angiography (DTDA) and spot fluoroscopy with that using conventional methods.Materials and MethodsAVS was performed in 11 patients using DTDA and spot fluoroscopy (Group A) and 11 patients using conventional digital subtraction angiography (DSA) with collimation (Group B). Radiation exposure and image quality of adrenal venography using a five-point scale were compared between the groups.ResultsThe acquisition dose–area product (DAP) using DTDA and fluoro-DAP using spot fluoroscopy in Group A were lower than those using conventional DSA (5.3 ± 3.7 vs. 29.1 ± 20.1 Gy cm{sup 2}, p < 0.001) and collimation (33.3 ± 22.9 vs. 59.1 ± 35.7 Gy cm{sup 2}, p = 0.088)more » in Group B. The total DAP in Group A was significantly lower than that in Group B (38.6 ± 25.9 vs. 88.2 ± 53.6 Gy cm{sup 2}, p = 0.006). The peak skin dose for patients and operator radiation exposure in Group A were significantly lower than those in Group B (403 ± 340 vs. 771 ± 416 mGy, p = 0.030, and 17.1 ± 14.8 vs. 36.6 ± 21.7 μSv, p = 0.013). The image quality of DTDA (4.4 ± 0.6) was significantly higher than that of digital angiography (3.8 ± 0.9, p = 0.011) and equivalent to that of DSA (4.3 ± 0.8, p = 0.651).ConclusionsRadiation exposure during AVS can be reduced by approximately half for both patients and operators by using DTDA and spot fluoroscopy without sacrificing image quality.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Das, Raj, E-mail: rajdas@nhs.net, E-mail: raj.das@stgeorges.nhs.uk; Lucatelli, Pierleone, E-mail: pierleone.lucatelli@gmail.com; Wang, Haofan, E-mail: wwhhff123@gmail.com

AimA clear understanding of operator experience is important in improving technical success whilst minimising patient risk undergoing endovascular procedures, and there is the need to ensure that trainees have the appropriate skills as primary operators. The aim of the study is to retrospectively analyse uterine artery embolisation (UAE) procedures performed by interventional radiology (IR) trainees at an IR training unit analysing fluoroscopy times and radiation dose as surrogate markers of technical skill.MethodsTen IR fellows were primary operator in 200 UAE procedures over a 5-year period. We compared fluoroscopy times, radiation dose and complications, after having them categorised according to threemore » groups: Group 1, initial five, Group 2, >5 procedures and Group 3, penultimate five UAE procedures. We documented factors that may affect screening time (number of vials employed and use of microcatheters).ResultsMean fluoroscopy time was 18.4 (±8.1), 17.3 (±9.0), 16.3 (±8.4) min in Groups 1, 2 and 3, respectively. There was no statistically significant difference between these groups (p > 0.05) with respect to fluoroscopy time or radiation dose. Analysis after correction for confounding factors showed no statistical significance (p > 0.05). All procedures were technically successful, and total complication rate was 4 %.ConclusionUAE was chosen as a highly standardised procedure followed by IR practitioners. Although there is a non-significant trend for shorter screening times with experience, technical success and safety were not compromised with appropriate Consultant supervision, which illustrates a safe construct for IR training. This is important and reassuring information for patients undergoing a procedure in a training unit.« less

Fluoroscopy-free Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) for controlling life threatening postpartum hemorrhage

PubMed Central

Stensaeth, Knut Haakon; Sovik, Edmund; Haig, Ingrid Natasha Ylva; Skomedal, Erna; Jorgensen, Arve

2017-01-01

Background Severe postpartum hemorrhage occurs in 1/1000 women giving birth. This condition is often dramatic and may be life threatening. Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) has in recent years been introduced as a novel treatment for hemorrhagic shock. We present a series of fluoroscopy-free REBOA for controlling life threatening postpartum hemorrhage. Methods In 2008 an ‘aortic occlusion kit’ was assembled and used in three Norwegian university hospitals. The on-call interventional radiologist (IR) was to be contacted with a response time < 30 minutes in case of life threatening PPH. Demographics and characteristics were noted from the medical records. Results This retrospective study includes 36 patients treated with fluoroscopy-free REBOA for controlling severe postpartum hemorrhage in the years 2008–2015. The REBOA success rate was 100% and no patients died from REBOA related complications. Uterine artery embolization was performed in 17 (47%) patients and a hysterectomy in 16 (44%) patients. A short (11cm) introducer length was strongly associated with iliac artery thrombus formation (ρ = 0.50, P = 0.002). In addition, there was a strong negative correlation between uterine artery embolization and hysterectomy (ρ = -0.50, P = 0.002). Conclusions Our Norwegian experience indicates the clinical safety and feasibility of REBOA in life threatening PPH. Also, REBOA can be used in an emergency situation without the use of fluoroscopy with a high degree of technical success. It is important that safety implementation of REBOA is established, especially through limited aortic balloon occlusion time and a thorough balloon deflation regime. PMID:28355242

Intraoperative positioning of mobile C-arms using artificial fluoroscopy

NASA Astrophysics Data System (ADS)

Dressel, Philipp; Wang, Lejing; Kutter, Oliver; Traub, Joerg; Heining, Sandro-Michael; Navab, Nassir

2010-02-01

In trauma and orthopedic surgery, imaging through X-ray fluoroscopy with C-arms is ubiquitous. This leads to an increase in ionizing radiation applied to patient and clinical staff. Placing these devices in the desired position to visualize a region of interest is a challenging task, requiring both skill of the operator and numerous X-rays for guidance. We propose an extension to C-arms for which position data is available that provides the surgeon with so called artificial fluoroscopy. This is achieved by computing digitally reconstructed radiographs (DRRs) from pre- or intraoperative CT data. The approach is based on C-arm motion estimation, for which we employ a Camera Augmented Mobile C-arm (CAMC) system, and a rigid registration of the patient to the CT data. Using this information we are able to generate DRRs and simulate fluoroscopic images. For positioning tasks, this system appears almost exactly like conventional fluoroscopy, however simulating the images from the CT data in realtime as the C-arm is moved without the application of ionizing radiation. Furthermore, preoperative planning can be done on the CT data and then visualized during positioning, e.g. defining drilling axes for pedicle approach techniques. Since our method does not require external tracking it is suitable for deployment in clinical environments and day-to-day routine. An experiment with six drillings into a lumbar spine phantom showed reproducible accuracy in positioning the C-arm, ranging from 1.1 mm to 4.1 mm deviation of marker points on the phantom compared in real and virtual images.

Registration of 2D to 3D joint images using phase-based mutual information

NASA Astrophysics Data System (ADS)

Dalvi, Rupin; Abugharbieh, Rafeef; Pickering, Mark; Scarvell, Jennie; Smith, Paul

2007-03-01

Registration of two dimensional to three dimensional orthopaedic medical image data has important applications particularly in the area of image guided surgery and sports medicine. Fluoroscopy to computer tomography (CT) registration is an important case, wherein digitally reconstructed radiographs derived from the CT data are registered to the fluoroscopy data. Traditional registration metrics such as intensity-based mutual information (MI) typically work well but often suffer from gross misregistration errors when the image to be registered contains a partial view of the anatomy visible in the target image. Phase-based MI provides a robust alternative similarity measure which, in addition to possessing the general robustness and noise immunity that MI provides, also employs local phase information in the registration process which makes it less susceptible to the aforementioned errors. In this paper, we propose using the complex wavelet transform for computing image phase information and incorporating that into a phase-based MI measure for image registration. Tests on a CT volume and 6 fluoroscopy images of the knee are presented. The femur and the tibia in the CT volume were individually registered to the fluoroscopy images using intensity-based MI, gradient-based MI and phase-based MI. Errors in the coordinates of fiducials present in the bone structures were used to assess the accuracy of the different registration schemes. Quantitative results demonstrate that the performance of intensity-based MI was the worst. Gradient-based MI performed slightly better, while phase-based MI results were the best consistently producing the lowest errors.

A cost effective and high fidelity fluoroscopy simulator using the Image-Guided Surgery Toolkit (IGSTK)

NASA Astrophysics Data System (ADS)

Gong, Ren Hui; Jenkins, Brad; Sze, Raymond W.; Yaniv, Ziv

2014-03-01

The skills required for obtaining informative x-ray fluoroscopy images are currently acquired while trainees provide clinical care. As a consequence, trainees and patients are exposed to higher doses of radiation. Use of simulation has the potential to reduce this radiation exposure by enabling trainees to improve their skills in a safe environment prior to treating patients. We describe a low cost, high fidelity, fluoroscopy simulation system. Our system enables operators to practice their skills using the clinical device and simulated x-rays of a virtual patient. The patient is represented using a set of temporal Computed Tomography (CT) images, corresponding to the underlying dynamic processes. Simulated x-ray images, digitally reconstructed radiographs (DRRs), are generated from the CTs using ray-casting with customizable machine specific imaging parameters. To establish the spatial relationship between the CT and the fluoroscopy device, the CT is virtually attached to a patient phantom and a web camera is used to track the phantom's pose. The camera is mounted on the fluoroscope's intensifier and the relationship between it and the x-ray source is obtained via calibration. To control image acquisition the operator moves the fluoroscope as in normal operation mode. Control of zoom, collimation and image save is done using a keypad mounted alongside the device's control panel. Implementation is based on the Image-Guided Surgery Toolkit (IGSTK), and the use of the graphics processing unit (GPU) for accelerated image generation. Our system was evaluated by 11 clinicians and was found to be sufficiently realistic for training purposes.

Is the 10th and 11th Intercostal Space a Safe Approach for Percutaneous Nephrostomy and Nephrolithotomy?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Muzrakchi, Ahmed Al; Szmigielski, W., E-mail: wojszmi@qatar.net.qa; Omar, Ahmed J.S.

2004-09-15

The aim of this study was to determine the rate of complications in percutaneous nephrostomy (PCN) and nephrolithotomy (PCNL) performed through the 11th and 10th intercostal spaces using our monitoring technique and to discuss the safety of the procedure. Out of 398 PCNs and PCNLs carried out during a 3-year period, 56 patients had 57 such procedures performed using an intercostal approach. The 11th intercostal route was used in 42 and the 10th in 15 cases. One patient had two separate nephrostomies performed through the 10th and 11th intercostal spaces. The technique utilizes bi-planar fluoroscopy with a combination of amore » conventional angiographic machine to provide anterior-posterior fluoroscopy and a C-arm mobile fluoroscopy machine to give a lateral view, displayed on two separate monitors. None of the patients had clinically significant thoracic or abdominal complications. Two patients had minor chest complications. Only one developed changes (plate atelectasis, elevation of the hemi-diaphragm) directly related to the nephrostomy (2%). The second patient had bilateral plate atelectasis and unilateral congestive lung changes after PCNL. These changes were not necessarily related to the procedure but rather to general anesthesia during nephrolithotomy. The authors consider PCN or PCNL through the intercostal approach a safe procedure with a negligible complication rate, provided that it is performed under bi-planar fluoroscopy, which allows determination of the skin entry point just below the level of pleural reflection and provides three-dimensional monitoring of advancement of the puncturing needle toward the target entry point.« less

Comparison of different approaches of estimating effective dose from reported exposure data in 3D imaging with interventional fluoroscopy systems

NASA Astrophysics Data System (ADS)

Svalkvist, Angelica; Hansson, Jonny; Bâth, Magnus

2014-03-01

Three-dimensional (3D) imaging with interventional fluoroscopy systems is today a common examination. The examination includes acquisition of two-dimensional projection images, used to reconstruct section images of the patient. The aim of the present study was to investigate the difference in resulting effective dose obtained using different levels of complexity in calculations of effective doses from these examinations. In the study the Siemens Artis Zeego interventional fluoroscopy system (Siemens Medical Solutions, Erlangen, Germany) was used. Images of anthropomorphic chest and pelvis phantoms were acquired. The exposure values obtained were used to calculate the resulting effective doses from the examinations, using the computer software PCXMC (STUK, Helsinki, Finland). The dose calculations were performed using three different methods: 1. using individual exposure values for each projection image, 2. using the mean tube voltage and the total DAP value, evenly distributed over the projection images, and 3. using the mean kV and the total DAP value, evenly distributed over smaller selection of projection images. The results revealed that the difference in resulting effective dose between the first two methods was smaller than 5%. When only a selection of projection images were used in the dose calculations the difference increased to over 10%. Given the uncertainties associated with the effective dose concept, the results indicate that dose calculations based on average exposure values distributed over a smaller selection of projection angles can provide reasonably accurate estimations of the radiation doses from 3D imaging using interventional fluoroscopy systems.

Effectiveness of imaging-guided intra-articular injection: a comparison study between fluoroscopy and ultrasound.

PubMed

Furtado, Rita Nely Vilar; Pereira, Daniele Freitas; da Luz, Karine Rodrigues; dos Santos, Marla Francisca; Konai, Monique Sayuri; Mitraud, Sonia de Aguiar Vilela; Rosenfeld, Andre; Fernandes, Artur da Rocha Correa; Natour, Jamil

2013-01-01

Compare the effectiveness of ultrasound and fluoroscopy to guide intra-articular injections (IAI) in selected cases. A prospective study in our outpatient clinics at the Rheumatology Division at Universidade Federal de São Paulo (UNIFESP), Brazil, was conducted to compare the short-term (4 weeks) effectiveness of ultrasound and fluoroscopy-guided IAI in patients with rheumatic diseases. Inclusion criteria were: adults with refractory synovitis undergoing IAI with glucocorticoid. All patients had IAI performed with triamcinolone hexacetonide (20mg/ml) with varying doses according to the joint injected. A total of 71 rheumatic patients were evaluated (52 women, 44 whites). Mean age was 51.9 ± 13 years and 47 of them (66.2%) were on regular DMARD use. Analysis of the whole sample (71 patients) and hip sub-analysis (23 patients) showed that significant improvement was observed for both groups in terms of pain (P < 0.001). Global analysis also demonstrated better outcomes for patients in the FCG in terms of joint flexion (P < 0.001) and percentage change in joint flexion as compared to the USG. Likert scale score analyses demonstrated better results for the patients in the USG as compared to the FCG at the end of the study (P < 0.05). No statistically significant difference between groups was observed for any other study variable. Imaging-guided IAI improves regional pain in patients with various types of synovitis in the short term. For the vast majority of variables, no significant difference in terms of effectiveness was observed between fluoroscopy and ultrasound guided IAI.

CT fluoroscopy guided transpleural cutting needle biopsy of small (≤2.5 cm) subpleural pulmonary nodules.

PubMed

Prosch, Helmut; Oschatz, Elisabeth; Eisenhuber, Edith; Wohlschlager, Helmut; Mostbeck, Gerhard H

2011-01-01

Small subpleural pulmonary lesions are difficult to biopsy. While the direct, short needle path has been reported to have a lower rate of pneumothorax, the indirect path provides a higher diagnostic yield. Therefore, we tried to optimize the needle pathway and minimize the iatrogenic pneumothorax risk by evaluating a CT fluoroscopy guided direct approach to biopsy subpleural lesions. Between 01/2005 and 01/2007, CT fluoroscopy guided core biopsies were performed in 24 patients. Using our technique, the tip of the guide needle remains outside the visceral pleura (17 G coaxial guide needle, 18 G Biopsy-gun, 15 or 22 mm needle path). The position of the lesion relative to the needle tip can be optimized using CT fluoroscopy by adjusting the breathing position of the patient. The Biopty gun is fired with the needle tip still outside the pleural space. Cytological smears are analyzed by a cytopathologist on-site, and biopsies are repeated as indicated with the coaxial needle still outside the pleura. Median nodule size was 1.6 cm (0.7-2.3 cm). A definitive diagnosis was obtained in 22 patients by histology and/or cytology. In one patient, only necrotic material could be obtained. In another patient, the intervention had to be aborted as the dyspnoic patient could not follow breathing instructions. An asymptomatic pneumothorax was present in seven patients; chest tube placement was not required. The presented biopsy approach has a high diagnostic yield and is especially advantageous for biopsies of small subpleural lesions in the lower lobes. Copyright © 2009 Elsevier Ireland Ltd. All rights reserved.

Effect of pulsed progressive fluoroscopy on reduction of radiation dose in the cardiac catheterization laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holmes, D.R. Jr.; Wondrow, M.A.; Gray, J.E.

1990-01-01

The increased application of therapeutic interventional cardiology procedures is associated with increased radiation exposure to physicians, patients and technical personnel. New advances in imaging techniques have the potential for reducing radiation exposure. A progressive scanning video system with a standard vascular phantom has been shown to decrease entrance radiation exposure. The effect of this system on reducing actual radiation exposure to physicians and technicians was assessed from 1984 through 1987. During this time, progressive fluoroscopy was added sequentially to all four adult catheterization laboratories; no changes in shielding procedures were made. During this time, the case load per physician increasedmore » by 63% and the number of percutaneous transluminal coronary angioplasty procedures (a high radiation procedure) increased by 244%. Despite these increases in both case load and higher radiation procedures, the average radiation exposure per physician declined by 37%. During the same time, the radiation exposure for technicians decreased by 35%. Pulsed progressive fluoroscopy is effective for reducing radiation exposure to catheterization laboratory physicians and technical staff.« less

Fluoroscopic exposure in modern spinal surgery.

PubMed

Fransen, Patrick

2011-06-01

The widespread use of minimally invasive and other spinal procedures raises concern about the peroperative radiation exposure to surgeon and patient. The authors noted the fluoroscopy time and the radiation dose, as read from the image amplifier, in 95 spinal procedures. The results of this prospective study varied widely between different operations. Percutaneous surgery was associated with more exposure than open surgery. For instance, the average radiation dose per pedicle screw was 3.2 times higher with percutaneous insertion than with an open approach. Therefore, efforts to reduce fluoroscopy time and radiation exposure should be made when using minimally invasive percutaneous surgical techniques. Preventive measures for the surgeon, such as lead aprons and gloves, thyroid shields, radioprotective glasses and staying away from the beam are recommended. Still from the surgeon's view-point, source inferior positioning of the image amplifier is indicated for the AP view, as well as monitoring of the radiation exposure. Finally, the difference in fluoroscopy time and radiation exposure between surgeons for the same procedure stresses the fact that peroperative radiation may be reduced by simple awareness and by training.

Editorial: ERCP-Related Radiation Cataractogenesis: Is It Time to Be Concerned?

PubMed

Mekaroonkamol, Parit; Keilin, Steven

2017-05-01

With the growing number of fluoroscopic guided endoscopic procedures, radiation-related risk needs to be further assessed. Recent evidence indicates that radiation cataractogenesis occurs at a lower dose threshold than previously believed. While body aprons and thyroid shields are well-established standard protection during fluoroscopy, ocular safety and the use of protective eyewear are not as well defined. This prospective study answered two important questions: Does the standard body dosimeter provide an accurate ocular dosimetry? And what is the time of fluoroscopy needed to warrant using lens protection? It also raises the question whether current guidelines need to be updated.

A combination of spatial and recursive temporal filtering for noise reduction when using region of interest (ROI) fluoroscopy for patient dose reduction in image guided vascular interventions with significant anatomical motion

NASA Astrophysics Data System (ADS)

Setlur Nagesh, S. V.; Khobragade, P.; Ionita, C.; Bednarek, D. R.; Rudin, S.

2015-03-01

Because x-ray based image-guided vascular interventions are minimally invasive they are currently the most preferred method of treating disorders such as stroke, arterial stenosis, and aneurysms; however, the x-ray exposure to the patient during long image-guided interventional procedures could cause harmful effects such as cancer in the long run and even tissue damage in the short term. ROI fluoroscopy reduces patient dose by differentially attenuating the incident x-rays outside the region-of-interest. To reduce the noise in the dose-reduced regions previously recursive temporal filtering was successfully demonstrated for neurovascular interventions. However, in cardiac interventions, anatomical motion is significant and excessive recursive filtering could cause blur. In this work the effects of three noise-reduction schemes, including recursive temporal filtering, spatial mean filtering, and a combination of spatial and recursive temporal filtering, were investigated in a simulated ROI dose-reduced cardiac intervention. First a model to simulate the aortic arch and its movement was built. A coronary stent was used to simulate a bioprosthetic valve used in TAVR procedures and was deployed under dose-reduced ROI fluoroscopy during the simulated heart motion. The images were then retrospectively processed for noise reduction in the periphery, using recursive temporal filtering, spatial filtering and a combination of both. Quantitative metrics for all three noise reduction schemes are calculated and are presented as results. From these it can be concluded that with significant anatomical motion, a combination of spatial and recursive temporal filtering scheme is best suited for reducing the excess quantum noise in the periphery. This new noise-reduction technique in combination with ROI fluoroscopy has the potential for substantial patient-dose savings in cardiac interventions.

Inserting pedicle screws in the upper thoracic spine without the use of fluoroscopy or image guidance. Is it safe?

PubMed

Schizas, Constantin; Theumann, Nicolas; Kosmopoulos, Victor

2007-05-01

Several studies have looked at accuracy of thoracic pedicle screw placement using fluoroscopy, image guidance, and anatomical landmarks. To our knowledge the upper thoracic spine (T1-T6) has not been specifically studied in the context of screw insertion and placement accuracy without the use of either image guidance or fluoroscopy. Our objective was to study the accuracy of upper thoracic screw placement without the use of fluoroscopy or image guidance, and report on implant related complications. A single surgeon inserted 60 screws in 13 consecutive non-scoliotic spine patients. These were the first 60 screws placed in the high thoracic spine in our institution. The most common diagnosis in our patient population was trauma. All screws were inserted using a modified Roy-Camille technique. Post-operative axial computed tomography (CT) images were obtained for each patient and analyzed by an independent senior radiologist for placement accuracy. Implant related complications were prospectively noted. No pedicle screw misplacement was found in 61.5% of the patients. In the remaining 38.5% of patients some misplacements were noted. Fifty-three screws out of the total 60 implanted were placed correctly within all the pedicle margins. The overall pedicle screw placement accuracy was 88.3% using our modified Roy-Camille technique. Five medial and two lateral violations were noted in the seven misplaced screws. One of the seven misplaced screws was considered to be questionable in terms of pedicle perforation. No implant related complications were noted. We found that inserting pedicle screws in the upper thoracic spine based solely on anatomical landmarks was safe with an accuracy comparable to that of published studies using image-guided navigation at the thoracic level.

Initial Investigation of Factors Influencing Radiation Dose to Patients Undergoing Barium-Based Fluoroscopy Procedures in Tanzania.

PubMed

Ngaile, J E; Msaki, P K; Kazema, R R; Schreiner, L J

2017-04-25

The aim of this study was to investigate the nature and causes of radiation dose imparted to patients undergoing barium-based X-ray fluoroscopy procedures in Tanzania and to compare these doses to those reported in the literature from other regions worldwide. The air kerma area product (KAP) to patient undergoing barium investigations of gastrointestinal tract system was obtained from four consultant hospitals. The KAP was determined using a flat transparent transmission ionization chamber. Mean values of KAP for barium swallow (BS), barium meal (BM) and barium enema (BE) were 2.79, 2.62 and 15.04 Gy cm2, respectively. The mean values of KAP per hospital for the BS, BM and BE procedures varied by factors of up to 7.3, 1.6 and 2.0, respectively. The overall difference between individual patient doses across the four consultant hospitals investigated differed by factors of up to 53, 29.5 and 12 for the BS, BM and BE procedures, respectively. The majority of the mean values of KAP was lower than the reported values for Ghana, Greece, Spain and the UK, while slightly higher than those reported for India. The observed wide variation of KAP values for the same fluoroscopy procedure within and among the hospitals was largely attributed to the dynamic nature of the procedures, the patient characteristics, the skills and experience of personnel, and the different examination protocols employed among hospitals. The observed great variations of procedural protocols and patient doses within and across the hospitals call for the need to standardize examination protocols and optimize barium-based fluoroscopy procedures. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Decreased Radiation Exposure and Increased Efficacy in Extracorporeal Lithotripsy Using a New Ultrasound Stone Locking System.

PubMed

Abid, Nadia; Ravier, Emmanuel; Promeyrat, Xavier; Codas, Ricardo; Fehri, Hakim Fassi; Crouzet, Sebastien; Martin, Xavier

2015-11-01

To compare fluoroscopy duration, radiation dose, and efficacy of two ultrasound stone localization systems during extracorporeal shockwave lithotripsy (SWL) treatment. Monocentric prospective data were obtained from patients consecutively treated for renal stones using the Sonolith(®) i-sys (EDAP TMS) lithotripter, with fluoroscopy combined with ultrasound localization using an "outline" Automatic Ultrasound Positioning Support (AUPS) (group A), or the "free-line" Visio-Track (VT) (EDAP-TMS) hand-held three-dimensional ultrasound stone locking system (group B). Efficacy rate was defined as the within-groups proportion stone free or with partial stone fragmentation not needing additional procedures. Statistical analysis used Pearson chi-square tests for categoric variables, nonparametric Mann-Whitney tests for continuous variables, and linear regression for operator learning curve with VT. Continuous variables were reported as median (range) values. Patients in group A (n=73) and group B (n=81) were comparable in baseline characteristics (age, kidney stone size, others) and in SWL application (duration, number of shocks, energy [Joules]). During SWL, the median (range) duration (seconds) of radiation exposure was 159.5 (0-690) in group A and 3.5 (0-478) in group B (P<0.001) and irradiation dose (mGy.cm(2)), 10598 (0-54843) in group A and 163 (0-13926) in group B (P<0.001). Fluoroscopy time significantly decreased with operator experience using VT. The efficacy rate was 54.5% in group A and 79.5% in group B (P=0.001). VT significantly reduced fluoroscopy use during SWL and the duration and dose of patient exposure to ionizing radiation. Stone treatment efficacy was significantly greater with VT mainly because of a better real-time monitoring of the stone.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jones, A. Kyle, E-mail: kyle.jones@mdanderson.org

Purpose: To evaluate the sensitivity of the diagnostic radiological index of protection (DRIP), used to quantify the protective value of radioprotective garments, to procedural factors in fluoroscopy in an effort to determine an appropriate set of scatter-mimicking primary beams to be used in measuring the DRIP. Methods: Monte Carlo simulations were performed to determine the shape of the scattered x-ray spectra incident on the operator in different clinical fluoroscopy scenarios, including interventional radiology and interventional cardiology (IC). Two clinical simulations studied the sensitivity of the scattered spectrum to gantry angle and patient size, while technical factors were varied according tomore » measured automatic dose rate control (ADRC) data. Factorial simulations studied the sensitivity of the scattered spectrum to gantry angle, field of view, patient size, and beam quality for constant technical factors. Average energy (E{sub avg}) was the figure of merit used to condense fluence in each energy bin to a single numerical index. Results: Beam quality had the strongest influence on the scattered spectrum in fluoroscopy. Many procedural factors affect the scattered spectrum indirectly through their effect on primary beam quality through ADRC, e.g., gantry angle and patient size. Lateral C-arm rotation, common in IC, increased the energy of the scattered spectrum, regardless of the direction of rotation. The effect of patient size on scattered radiation depended on ADRC characteristics, patient size, and procedure type. Conclusions: The scattered spectrum striking the operator in fluoroscopy is most strongly influenced by primary beam quality, particularly kV. Use cases for protective garments should be classified by typical procedural primary beam qualities, which are governed by the ADRC according to the impacts of patient size, anatomical location, and gantry angle.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jones, A; Pasciak, A; Wagner, L

Purpose: To evaluate the sensitivity of the Diagnostic Radiological Index of Protection (DRIP) to procedural factors in fluoroscopy in an effort to determine an appropriate set of scatter-mimicking primary beams (SMPB) to be used in measuring the DRIP. Methods: A series of clinical and factorial Monte Carlo simulations were conducted to determine the shape of the scattered X-ray spectra incident on the operator in different clinical fluoroscopy scenarios. Two clinical evaluations studied the sensitivity of the scattered spectrum to gantry angle and patient size while technical factors were varied according to measured automatic dose rate control (ADRC) data. Factorial evaluationsmore » studied the sensitivity of the scattered spectrum to gantry angle, field of view, patient size and beam quality for constant technical factors. Average energy was the figure of merit used to condense fluence in each energy bin to a single numerical index. Results: Beam quality had the strongest influence on the scattered spectrum in fluoroscopy. Many procedural factors affected the scattered spectrum indirectly through their effects on primary beam quality through ADRC, e.g., gantry angle and patient size. Lateral C-arm rotation, common in interventional cardiology, increased the energy of the scattered spectrum, regardless of the direction of rotation. The effect of patient size on scattered radiation depended on ADRC characteristics, patient size, and procedure type. Conclusion: The scattered spectrum striking the operator in fluoroscopy, and therefore the DRIP, is most strongly influenced by primary beam quality, particularly kV. Use cases for protective garments should be classified by typical procedural primary beam qualities, which are governed by the ADRC according to the impacts of patient size, anatomical location, and gantry angle. These results will help determine an appropriate set of SMPB to be used for measuring the DRIP.« less

Use of fluoroscopy-guided wire manipulation and/or laparoscopic surgery in the repair of malfunctioning peritoneal dialysis catheters.

PubMed

Kim, Hee Jin; Lee, Tae Won; Ihm, Chun Gyoo; Kim, Myung Jae

2002-01-01

Peritoneal catheter is the lifeline for the continuous ambulatory peritoneal dialysis (CAPD) patients. Over the years, obstruction or displacement of the CAPD catheter has been one of the common complications of CAPD. Fluoroscopy-guided wire manipulation or laparoscopic surgery has been developed to manage outflow obstruction. We analyzed the catheter outcome of fluoroscopy-guided wire manipulation or laparoscopic surgery to determine the ultimate benefit of these procedures. From June 1996 to August 2000, catheter complications were manipulated in 24 patients. Eleven (46%) of these patients were initially managed by guide wire under fluoroscopic control. The remaining 13 (54%) patients were manipulated by laparoscopic surgery. A successful outcome was defined as maintained normal peritoneal catheter function at 30 days after the manipulations. Among the catheters manipulated, 18 (75%) were inserted by nephrologist and 6 (25%) by surgeons at the initiation of CAPD. Tenckhoff double-cuff peritoneal catheters were inserted to all patients. The time elapsed between catheter insertion and manipulation varied from 1 to 60 days with a mean of 11 days. The primary causes of catheter malfunction were kinking in 1 case, omental wrapping with adhesions in 9 cases, and catheter displacements in the remaining 14 cases. Thirty-day catheter function was achieved in 50% (12/24) of initial catheter manipulations, with guide wire under fluoroscopic control (46%, 5/11) and laparoscopic surgery (54%, 7/13). Overall success rate of repeated manipulation was 71% (17 of 24). The successful outcome in repairing of the malfunctioning CAPD catheters could be increased by the combination of fluoroscopy-guided wire manipulation and laparoscopic surgery. Copyright 2002 S. Karger AG, Basel

Training for percutaneous renal access on a virtual reality simulator.

PubMed

Zhang, Yi; Yu, Cheng-fan; Liu, Jin-shun; Wang, Gang; Zhu, He; Na, Yan-qun

2013-01-01

The need to develop new methods of surgical training combined with advances in computing has led to the development of virtual reality surgical simulators. The PERC Mentor(TM) is designed to train the user in percutaneous renal collecting system access puncture. This study aimed to validate the use of this kind of simulator, in percutaneous renal access training. Twenty-one urologists were enrolled as trainees to learn a fluoroscopy-guided percutaneous renal accessing technique. An assigned percutaneous renal access procedure was immediately performed on the PERC Mentor(TM) after watching instruction video and an analog operation. Objective parameters were recorded by the simulator and subjective global rating scale (GRS) score were determined. Simulation training followed and consisted of 2 hours daily training sessions for 2 consecutive days. Twenty-four hours after the training session, trainees were evaluated performing the same procedure. The post-training evaluation was compared to the evaluation of the initial attempt. During the initial attempt, none of the trainees could complete the appointed procedure due to the lack of experience in fluoroscopy-guided percutaneous renal access. After the short-term training, all trainees were able to independently complete the procedure. Of the 21 trainees, 10 had primitive experience in ultrasound-guided percutaneous nephrolithotomy. Trainees were thus categorized into the group of primitive experience and inexperience. The total operating time and amount of contrast material used were significantly lower in the group of primitive experience versus the inexperience group (P = 0.03 and 0.02, respectively). The training on the virtual reality simulator, PERC Mentor(TM), can help trainees with no previous experience of fluoroscopy-guided percutaneous renal access to complete the virtual manipulation of the procedure independently. This virtual reality simulator may become an important training and evaluation tool in teaching fluoroscopy-guided percutaneous renal access.

[Assessment of the surgeon radiation exposure during a minimally invasive TLIF: Comparison between fluoroscopy and O-arm system].

PubMed

Grelat, M; Zairi, F; Quidet, M; Marinho, P; Allaoui, M; Assaker, R

2015-08-01

Transforaminal lumbar interbody fusion with a minimally invasive approach (MIS TLIF) has become a very popular technique in the treatment of degenerative diseases of the lumbar spine, as it allows a decrease in muscle iatrogenic. However, iterative radiological controls inherent to this technique are responsible for a significant increase in exposure to ionizing radiation for the surgeon. New techniques for radiological guidance (O-arm navigation-assisted) would overcome this drawback, but this remains unproven. To analyze the exposure of the surgeon to intraoperative X-ray during a MIS TLIF under fluoroscopy and under O-arm navigation-assisted. This prospective study was conducted at the University Hospital of Lille from February to May 2013. Twelve patients underwent a MIS TLIF for the treatment of low-grade spondylolisthesis; six under standard fluoroscopy (group 1) and six under O-arm system (group 2). Passive dosimeters (rings and glasses) and active dosimeters for thorax were used to measure the radiation exposure of the surgeon. For group 1, the average time of fluoroscopy was 3.718 minutes (3.13-4.56) while no radioscopy was perform on group 2. For the first group, the average exposure dose was 12 μSv (5-20 μSv) on the thorax, 1168 μSv (510-2790 μSv) on the main hand and 179 μSv (103-486 μSv) on the lens. The exposure dose was measured zero on the second group. The maximum recommended doses can be reached, mainly for the lens. In addition to the radioprotection measures, O-arm navigation systems are safe alternatives to significantly reduce surgeon exposure. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Total Navigation in Spine Surgery; A Concise Guide to Eliminate Fluoroscopy Using a Portable Intraoperative Computed Tomography 3-Dimensional Navigation System.

PubMed

Navarro-Ramirez, Rodrigo; Lang, Gernot; Lian, Xiaofeng; Berlin, Connor; Janssen, Insa; Jada, Ajit; Alimi, Marjan; Härtl, Roger

2017-04-01

Portable intraoperative computed tomography (iCT) with integrated 3-dimensional navigation (NAV) offers new opportunities for more precise navigation in spinal surgery, eliminates radiation exposure for the surgical team, and accelerates surgical workflows. We present the concept of "total navigation" using iCT NAV in spinal surgery. Therefore, we propose a step-by-step guideline demonstrating how total navigation can eliminate fluoroscopy with time-efficient workflows integrating iCT NAV into daily practice. A prospective study was conducted on collected data from patients undergoing iCT NAV-guided spine surgery. Number of scans, radiation exposure, and workflow of iCT NAV (e.g., instrumentation, cage placement, localization) were documented. Finally, the accuracy of pedicle screws and time for instrumentation were determined. iCT NAV was successfully performed in 117 cases for various indications and in all regions of the spine. More than half (61%) of cases were performed in a minimally invasive manner. Navigation was used for skin incision, localization of index level, and verification of implant position. iCT NAV was used to evaluate neural decompression achieved in spinal fusion surgeries. Total navigation eliminates fluoroscopy in 75%, thus reducing staff radiation exposure entirely. The average times for iCT NAV setup and pedicle screw insertion were 12.1 and 3.1 minutes, respectively, achieving a pedicle screw accuracy of 99%. Total navigation makes spine surgery safer and more accurate, and it enhances efficient and reproducible workflows. Fluoroscopy and radiation exposure for the surgical staff can be eliminated in the majority of cases. Copyright © 2017 Elsevier Inc. All rights reserved.

Pros and Cons of 3D Image Fusion in Endovascular Aortic Repair: A Systematic Review and Meta-analysis.

PubMed

Goudeketting, Seline R; Heinen, Stefan G H; Ünlü, Çağdaş; van den Heuvel, Daniel A F; de Vries, Jean-Paul P M; van Strijen, Marco J; Sailer, Anna M

2017-08-01

To systematically review and meta-analyze the added value of 3-dimensional (3D) image fusion technology in endovascular aortic repair for its potential to reduce contrast media volume, radiation dose, procedure time, and fluoroscopy time. Electronic databases were systematically searched for studies published between January 2010 and March 2016 that included a control group describing 3D fusion imaging in endovascular aortic procedures. Two independent reviewers assessed the methodological quality of the included studies and extracted data on iodinated contrast volume, radiation dose, procedure time, and fluoroscopy time. The contrast use for standard and complex endovascular aortic repairs (fenestrated, branched, and chimney) were pooled using a random-effects model; outcomes are reported as the mean difference with 95% confidence intervals (CIs). Seven studies, 5 retrospective and 2 prospective, involving 921 patients were selected for analysis. The methodological quality of the studies was moderate (median 17, range 15-18). The use of fusion imaging led to an estimated mean reduction in iodinated contrast of 40.1 mL (95% CI 16.4 to 63.7, p=0.002) for standard procedures and a mean 70.7 mL (95% CI 44.8 to 96.6, p<0.001) for complex repairs. Secondary outcome measures were not pooled because of potential bias in nonrandomized data, but radiation doses, procedure times, and fluoroscopy times were lower, although not always significantly, in the fusion group in 6 of the 7 studies. Compared with the control group, 3D fusion imaging is associated with a significant reduction in the volume of contrast employed for standard and complex endovascular aortic procedures, which can be particularly important in patients with renal failure. Radiation doses, procedure times, and fluoroscopy times were reduced when 3D fusion was used.

A statistical model of catheter motion from interventional x-ray images: application to image-based gating

NASA Astrophysics Data System (ADS)

Panayiotou, M.; King, A. P.; Ma, Y.; Housden, R. J.; Rinaldi, C. A.; Gill, J.; Cooklin, M.; O'Neill, M.; Rhode, K. S.

2013-11-01

The motion and deformation of catheters that lie inside cardiac structures can provide valuable information about the motion of the heart. In this paper we describe the formation of a novel statistical model of the motion of a coronary sinus (CS) catheter based on principal component analysis of tracked electrode locations from standard mono-plane x-ray fluoroscopy images. We demonstrate the application of our model for the purposes of retrospective cardiac and respiratory gating of x-ray fluoroscopy images in normal dose x-ray fluoroscopy images, and demonstrate how a modification of the technique allows application to very low dose scenarios. We validated our method on ten mono-plane imaging sequences comprising a total of 610 frames from ten different patients undergoing radiofrequency ablation for the treatment of atrial fibrillation. For normal dose images we established systole, end-inspiration and end-expiration gating with success rates of 100%, 92.1% and 86.9%, respectively. For very low dose applications, the method was tested on the same ten mono-plane x-ray fluoroscopy sequences without noise and with added noise at signal to noise ratio (SNR) values of √50, √10, √8, √6, √5, √2 and √1 to simulate the image quality of increasingly lower dose x-ray images. The method was able to detect the CS catheter even in the lowest SNR images with median errors not exceeding 2.6 mm per electrode. Furthermore, gating success rates of 100%, 71.4% and 85.7% were achieved at the low SNR value of √2, representing a dose reduction of more than 25 times. Thus, the technique has the potential to extract useful information whilst substantially reducing the radiation exposure.

Sports-Related Groin Pain Secondary to Symphysis Pubis Disorders: Correlation Between MRI Findings and Outcome After Fluoroscopy-Guided Injection of Steroid and Local Anesthetic.

PubMed

Byrne, Caoimhe A; Bowden, Dermot J; Alkhayat, Abdullah; Kavanagh, Eoin C; Eustace, Stephen J

2017-08-01

The objective of our study was to correlate patterns of injury on preprocedural MRI with outcome after targeted fluoroscopy-guided steroid and local anesthetic injection of the symphysis pubis and its muscular attachments in a group of athletes with chronic groin pain. Forty-five patients with chronic sports-related groin pain underwent MRI of the pelvis and a targeted fluoroscopy-guided symphyseal corticosteroid and local anesthetic injection. Preprocedural MRI was reviewed. The presence or absence of a "superior cleft" sign (i.e., rectus abdominis-adductor longus attachment microtearing), "secondary cleft" sign (i.e., short adductor [gracilis, adductor brevis, and pectineus muscles] attachment microtearing), osteitis pubis, and extrasymphyseal pelvic abnormalities was recorded. Patients were followed up a mean time of 23 months after the procedure, and outcome was recorded. Correlation was made between preprocedural MRI findings and outcome. Forty-two percent of the patients had an isolated superior cleft sign, 7% had an isolated secondary cleft sign, and 11% had isolated osteitis pubis. Thirty-one percent of patients had a more complex injury, and 9% had a normal symphysis pubis. Overall, 89% of the patients experienced an improvement in symptoms. The response was sustained after a minimum of 6 months in 58% of the patients. The presence of the superior cleft sign was more frequently associated with a complete recovery. Fluoroscopy-guided corticosteroid symphyseal injection is a safe and effective treatment of sports-related groin pain. It is more frequently associated with a complete recovery in patients who display an isolated superior cleft sign on MRI. MRI not only is useful in characterizing groin injuries but also may be helpful in predicting response to therapeutic injection.

Latest-generation catheterization systems enable invasive submillisievert coronary angiography.

PubMed

Kuon, E; Weitmann, K; Hummel, A; Dörr, M; Reffelmann, T; Riad, A; Busch, M C; Felix, S B; Hoffmann, W; Empen, K

2015-05-01

The radiation risk of patients undergoing invasive cardiology remains considerable and includes skin injuries and cancer. To date, submillisievert coronary angiography has not been considered feasible. In 2011, we compared results from 100 consecutive patients undergoing elective coronary angiography using the latest-generation flat-panel angiography system (FPS) with results from examinations by the same operator using 106 historic controls with a conventional image-intensifier system (IIS) that was new in 2002. The median patient exposure parameters were measured as follows: dose-area product (DAP) associated with radiographic cine acquisitions (DAP(R)) and fluoroscopy (DAP(F)) scenes, radiographic frames and runs, and cumulative exposure times for radiography and fluoroscopy. On the FPS as compared to the traditional IIS, radiographic detector entrance dose levels were reduced from 164 to 80 nGy/frame and pulse rates were lowered from 12.5/s to 7.5/s during radiography and from 25/s to 4/s during fluoroscopy. The cardiologist's performance patterns remained comparable over the years: fluoroscopy time was constant and radiography time even slightly increased. Overall patient DAP decreased from 7.0 to 2.4 Gy × cm(2); DAP(R), from 4.2 to 1.7 Gy × cm(2); and DAP(F), from 2.8 to 0.6 Gy × cm(2). Time-adjusted DAP(R)/s decreased from 436 to 130 mGy × cm(2) and DAP(F)/s, from 21.6 to 4.4 mGy × cm(2). Cumulative patient skin dose with the FPS amounted to 67 mGy, and the median (interquartile range) of effective dose was 0.5 (0.3 … 0.7) mSv. Consistent application of radiation-reducing techniques with the latest-generation flat-panel systems enables submillisievert coronary angiography in invasive cardiology.

Comparison of fluoro and cine coronary angiography: balancing acceptable outcomes with a reduction in radiation dose.

PubMed

Olcay, Ayhan; Guler, Ekrem; Karaca, Ibrahim Oguz; Omaygenc, Mehmet Onur; Kizilirmak, Filiz; Olgun, Erkam; Yenipinar, Esra; Cakmak, Huseyin Altug; Duman, Dursun

2015-04-01

Use of last fluoro hold (LFH) mode in fluoroscopy, which enables the last live image to be saved and displayed, could reduce radiation during percutaneous coronary intervention when compared with cine mode. No previous study compared coronary angiography radiation doses and image quality between LFH and conventional cine mode techniques. We compared cumulative dose-area product (DAP), cumulative air kerma, fluoroscopy time, contrast use, interobserver variability of visual assessment between LFH angiography, and conventional cine angiography techniques. Forty-six patients were prospectively enrolled into the LFH group and 82 patients into the cine angiography group according to operator decision. Mean cumulative DAP was higher in the cine group vs the LFH group (50058.98 ± 53542.71 mGy•cm² vs 11349.2 ± 8796.46 mGy•cm²; P<.001). Mean fluoroscopy times were higher in the cine group vs the LFH group (3.87 ± 5.08 minutes vs 1.66 ± 1.51 minutes; P<.01). Mean contrast use was higher in the cine group vs the LFH group (112.07 ± 43.79 cc vs 88.15 ± 23.84 cc; P<.001). Mean value of Crombach's alpha was not statistically different between visual estimates of three operators between cine and LFH angiography groups (0.66680 ± 0.19309 vs 0.54193 ± 0.31046; P=.20). Radiation doses, contrast use, and fluoroscopy times are lower in fluoroscopic LFH angiography vs cine angiography. Interclass variability of visual stenosis estimation between three operators was not different between cine and LFH groups. Fluoroscopic LFH images conventionally have inferior diagnostic quality when compared with cine coronary angiography, but with new angiographic systems with improved LFH image quality, these images may be adequate for diagnostic coronary angiography.

Percutaneous radiofrequency ablation for osteoid osteoma under guidance of threedimensional fluoroscopy.

PubMed

Arıkan, Yavuz; Yavuz, Umut; Lapcin, Osman; Sökücü, Sami; Özkan, Bilge; Kabukçuoğlu, Yavuz

2016-12-01

To evaluate the outcome of percutaneous radiofrequency ablation under guidance of 3-dimensional fluoroscopy in 17 patients with osteoid osteoma. Records of 11 male and 6 female consecutive patients aged 4 to 28 (mean, 13.8) years who underwent radiofrequency ablation under guidance of 3-dimensional fluoroscopy for osteoid osteoma and were followed up for a mean of 15.8 (range, 12-28) months were reviewed. All patients had been treated with analgesics but failed to achieve lasting pain relief. Visual analogue score (VAS) for pain was assessed pre- and post-operatively. Absence of pain was considered recovery. The mean operating time was 55 (range, 20-95) minutes, and the mean length of hospital stay was 2.8 (range, 2-7) days. The mean amount of radiation was 390.2 (range, 330.5-423.6) mGy/cm. Relief of pain occurred within the first 24 hours in 11 patients and by the end of the first week in 3 patients. Pain persisted in 3 patients at one month; they underwent revision surgery and achieved complete recovery. The mean VAS for pain was 7.2 (range, 6-9) in 17 patients preoperatively and decreased to 0.64 (range, 0-2) in the 14 patients with pain relief and 0.66 (range, 0-1) in the 3 patients after revision surgery. Two patients had severe discharge from the wound secondary to fat necrosis, which resolved within a week with antibiotics and local dressings. No patient had cellulitis, vasomotor instability, neurovascular injury, fracture, or deep infection. Percutaneous radiofrequency ablation under guidance of 3-dimensional fluoroscopy is a viable treatment option for osteoid osteoma.

Fluoroscopy-assisted vs fluoroless endoscopic ultrasound-guided transmural drainage of pancreatic fluid collections: A comparative study.

PubMed

Consiglieri, Claudia F; Gornals, Joan B; Busquets, Juli; Peláez, Nuria; Secanella, Lluis; De-La-Hera, Meritxell; Sanzol, Resurrección; Fabregat, Joan; Castellote, José

2018-01-01

The need for fluoroscopy guidance in patients undergoing endoscopic ultrasound-guided transmural drainage (EUS-TMD) of peripancreatic fluid collections (PFCs) remains unclear. The aim of this study was to compare general outcomes of EUS-TMD of PFCs under fluoroscopy (F) vs fluoroless (FL). This is a comparative study with a retrospective analysis of a prospective and consecutive inclusion database at a tertiary centre, from 2009 to 2015. All patients were symptomatic pseudocyst (PSC) and walled-off pancreatic necrosis (WON). Two groups were assigned depending on availability of fluoroscopy. The groups were heterogeneous in terms of their demographic characteristics, PFCs and procedure. The main outcome measures included technical and clinical success, incidences, adverse events (AEs), and follow-up. Fifty EUS-TMD of PFCs from 86 EUS-guided drainages were included during the study period. Group F included 26 procedures, PSC 69.2%, WON 30.8%, metal stents 61.5% (46.1% lumen-apposing stent) and plastic stents 38.5%. Group FL included 24 procedures, PSC 37.5%, WON 62.5%, and metal stents 95.8% (lumen-apposing stents). Technical success was 100% in both groups, and clinical success was similar (F 88.5%, FL 87.5%). Technical incidences and intra-procedure AEs were only described in group F (7.6% and 11.5%, respectively) and none in group FL. Procedure time was less in group FL (8min, p=0.0341). Fluoroless in the EUS-TMD of PFCs does not involve more technical incidences or intra-procedure AEs. Technical and clinical success was similar in the two groups. Copyright © 2017 Elsevier España, S.L.U. All rights reserved.

Digital tumor fluoroscopy (DTF)--a new direct imaging system in the therapy planning for brain tumors.

PubMed

Herbst, M; Fröder, M

1990-01-01

Digital Tumor Fluoroscopy is an expanded x-ray video chain optimized to iodine contrast with an extended Gy scale up to 64000 Gy values. Series of pictures are taken before and after injection of contrast medium. With the most recent unit, up to ten images can be taken and stored. The microprogrammable processor allows the subtraction of images recorded at any moment of the examination. Dynamic views of the distribution of contrast medium in the intravasal and extravasal spaces of brain and tumor tissue are gained by the subtraction of stored images. Tumors can be differentiated by studying the storage and drainage behavior of the contrast medium during the period of examination. Meningiomas store contrast medium very intensively during the whole time of investigation, whereas astrocytomas grade 2-3 pick it up less strongly at the beginning and release it within 2 min. Glioblastomas show a massive but delayed accumulation of contrast medium and a decreased flow-off-rate. In comparison with radiography and MR-imaging the most important advantage of Digital Tumor Fluoroscopy is that direct information on tumor localization is gained in relation to the skull-cap. This enables the radiotherapist to mark the treatment field directly on the skull. Therefore it is no longer necessary to calculate the tumor volume from several CT scans for localization. In radiotherapy Digital Tumor Fluoroscopy a unit combined with a simulator can replace CT planning. This would help overcome the disadvantages arising from the lack of a collimating system, and the inaccuracies which result from completely different geometric relationships between a CT unit and a therapy machine.

Predictors of thrombotic complications and mass effect exacerbation after pipeline embolization: The significance of adenosine diphosphate inhibition, fluoroscopy time, and aneurysm size.

PubMed

Raychev, Radoslav; Tateshima, Satoshi; Vinuela, Fernando; Sayre, Jim; Jahan, Reza; Gonzalez, Nestor; Szeder, Viktor; Duckwiler, Gary

2016-02-01

The mechanisms leading to delayed rupture, distal emboli and intraparenchymal hemorrhage in relation to pipeline embolization device (PED) placement remain debatable and poorly understood. The aim of this study was to identify clinical and procedural predictors of these perioperative complications. We conducted a retrospective review of consecutive patients who underwent PED placement. We utilized a non-commercial platelet aggregation method measuring adenosine diphosphate (ADP)% inhibition for evaluation of clopidogrel response. To our knowledge, this is the first study to test ADP in neurovascular procedures. Multivariable regression analysis was used to identify the strongest predictor of three separate outcomes: (1) thrombotic complications, (2) hemorrhagic complications, and (3) aneurysm mass effect exacerbation Permanent complication-related morbidity and mortality at 3 months was 6% (3/48). No specific predictors of hemorrhagic complications were identified. In the univariate analysis, the strongest predictors of thrombotic complications were: ADP% inhibition<49 (p=0.01), aneurysm size (p=0.04) and fluoroscopy time (p=0.002). In the final multivariate analysis, among all baseline variables, fluoroscopy time exceeding 52 min was the only factor associated with thrombotic complications (p=0.007). Aneurysm size≥18 mm was the single predictor of mass effect exacerbation (p=0.039). Procedural complexity, reflected by fluoroscopy time, is the strongest predictor of thrombotic complications in this study. ADP% inhibition is a reliable method of testing clopidogrel response in neurovascular procedures and values of <50% may predict thrombotic complications. Interval mass effect exacerbation after PED placement may be anticipated in large aneurysms exceeding 18 mm. © The Author(s) 2015.

Fluoroscopy of spontaneous breathing is more sensitive than phrenic nerve stimulation for detection of right phrenic nerve injury during cryoballoon ablation of atrial fibrillation.

PubMed

Linhart, Markus; Nielson, Annika; Andrié, René P; Mittmann-Braun, Erica L; Stöckigt, Florian; Kreuz, Jens; Nickenig, Georg; Schrickel, Jan W; Lickfett, Lars M

2014-08-01

Right phrenic nerve palsy (PNP) is a typical complication of cryoballoon ablation of the right-sided pulmonary veins (PVs). Phrenic nerve function can be monitored by palpating the abdomen during phrenic nerve pacing from the superior vena cava (SVC pacing) or by fluoroscopy of spontaneous breathing. We sought to compare the sensitivity of these 2 techniques during cryoballoon ablation for detection of PNP. A total of 133 patients undergoing cryoballoon ablation were monitored with both SVC pacing and fluoroscopy of spontaneous breathing during ablation of the right superior PV. PNP occurred in 27/133 patients (20.0%). Most patients (89%) had spontaneous recovery of phrenic nerve function at the end of the procedure or on the following day. Three patients were discharged with persistent PNP. All PNP were detected first by fluoroscopic observation of diaphragm movement during spontaneous breathing, while diaphragm could still be stimulated by SVC pacing. In patients with no recovery until discharge, PNP occurred at a significantly earlier time (86 ± 34 seconds vs. 296 ± 159 seconds, P < 0.001). No recovery occurred in 2/4 patients who were ablated with a 23 mm cryoballoon as opposed to 1/23 patients with a 28 mm cryoballoon (P = 0.049). Fluoroscopic assessment of diaphragm movement during spontaneous breathing is more sensitive for detection PNP as compared to SVC pacing. PNP as assessed by fluoroscopy is frequent (20.0%) and carries a high rate of recovery (89%) until discharge. Early onset of PNP and use of 23 mm cryoballoon are associated with PNP persisting beyond hospital discharge. © 2014 Wiley Periodicals, Inc.

High-Resolution Three-Dimensional Computed Tomography for Assessing Complications Related to Intrathecal Drug Delivery.

PubMed

Morgalla, Matthias; Fortunato, Marcos; Azam, Ala; Tatagiba, Marcos; Lepski, Guillherme

2016-07-01

The assessment of the functionality of intrathecal drug delivery (IDD) systems remains difficult and time-consuming. Catheter-related problems are still very common, and sometimes difficult to diagnose. The aim of the present study is to investigate the accuracy of high-resolution three-dimensional computed tomography (CT) in order to detect catheter-related pump dysfunction. An observational, retrospective investigation. Academic medical center in Germany. We used high-resolution three dimensional (3D) computed tomography with volume rendering technique (VRT) or fluoroscopy and conventional axial-CT to assess IDD-related complications in 51 patients from our institution who had IDD systems implanted for the treatment of chronic pain or spasticity. Twelve patients (23.5%) presented a total of 22 complications. The main type of complication in our series was catheter-related (50%), followed by pump failure, infection, and inappropriate refilling. Fluoroscopy and conventional CT were used in 12 cases. High-resolution 3D CT VRT scan was used in 35 instances with suspected yet unclear complications. Using 3D-CT (VRT) the sensitivity was 58.93% - 100% (CI 95%) and the specificity 87.54% - 100% (CI 95%).The positive predictive value was 58.93% - 100% (CI 95%) and the negative predictive value: 87.54% - 100% (CI 95%).Fluoroscopy and axial CT as a combined diagnostic tool had a sensitivity of 8.3% - 91.7% (CI 95%) and a specificity of 62.9% - 100% (CI 95%). The positive predictive value was 19.29% - 100% (CI 95%) and the negative predictive value: 44.43% - 96.89% (CI 95%). This study is limited by its observational design and the small number of cases. High-resolution 3D CT VRT is a non- invasive method that can identify IDD-related complications with more precision than axial CT and fluoroscopy.

Insertion of tunneled hemodialysis catheters without fluoroscopy.

PubMed

Motta Elias, Rosilene; da Silva Makida, Sonia Cristina; Abensur, Hugo; Martins Castro, Manuel Carlos; Affonso Moysés, Rosa Maria; Pereira, Benedito Jorge; Bueno de Oliveira, Rodrigo; Luders, Cláudio; Romão, João Egidio

2010-01-01

The tunneled cuffed catheter (TCC) is used as a bridge access for hemodialysis. Few prospective studies have been designed to evaluate conversion from non-tunneled to TCC without the use of fluoroscopy when performed by nephrologists. We performed an observational prospective cohort in incident patients receiving hemodialysis through a non-tunneled right jugular vein catheter. 130 procedures were performed in 122 patients (51+/-18 years). The success rate was 100%. There was a total of 26,546 catheter days. Ninety-one of the 130 catheters were removed during the study period. Life table analysis revealed primary patency rates of 92%, 82%, and 68% at 30, 60, and 120 days, respectively. Infection requiring catheter removal occurred at a frequency of 0.09 per 100 catheter days. Catheter malfunction requiring intervention occurred at a rate of 0.03 per 100 catheter days. Hypertension and duration of existing non-tunneled catheter of less than 2 weeks were independently associated with better TCC survival. The conversion from non-tunneled to TCC performed by nephrologists and without fluoroscopy may be safe by using the internal right jugular vein. The ideal time to do this procedure is within less than 2 weeks of existing non-tunneled catheter.

An MR-based Model for Cardio-Respiratory Motion Compensation of Overlays in X-Ray Fluoroscopy

PubMed Central

Fischer, Peter; Faranesh, Anthony; Pohl, Thomas; Maier, Andreas; Rogers, Toby; Ratnayaka, Kanishka; Lederman, Robert; Hornegger, Joachim

2017-01-01

In X-ray fluoroscopy, static overlays are used to visualize soft tissue. We propose a system for cardiac and respiratory motion compensation of these overlays. It consists of a 3-D motion model created from real-time MR imaging. Multiple sagittal slices are acquired and retrospectively stacked to consistent 3-D volumes. Slice stacking considers cardiac information derived from the ECG and respiratory information extracted from the images. Additionally, temporal smoothness of the stacking is enhanced. Motion is estimated from the MR volumes using deformable 3-D/3-D registration. The motion model itself is a linear direct correspondence model using the same surrogate signals as slice stacking. In X-ray fluoroscopy, only the surrogate signals need to be extracted to apply the motion model and animate the overlay in real time. For evaluation, points are manually annotated in oblique MR slices and in contrast-enhanced X-ray images. The 2-D Euclidean distance of these points is reduced from 3.85 mm to 2.75 mm in MR and from 3.0 mm to 1.8 mm in X-ray compared to the static baseline. Furthermore, the motion-compensated overlays are shown qualitatively as images and videos. PMID:28692969

Multicenter, randomized comparison between magnetically navigated and manually guided radiofrequency ablation of atrioventricular nodal reentrant tachycardia (the MagMa-AVNRT-trial).

PubMed

Reents, Tilko; Jilek, Clemens; Schuster, Peter; Nölker, Georg; Koch-Büttner, Katharina; Ammar-Busch, Sonia; Semmler, Verena; Bourier, Felix; Kottmaier, Marc; Kornmayer, Marie; Brooks, Stephanie; Fichtner, Stephanie; Kolb, Christof; Deisenhofer, Isabel; Hessling, Gabriele

2017-12-01

Remote magnetic navigation (RMN) is attributed to diminish radiation exposure for both patient and operator performing catheter ablation for different arrhythmia substrates. The purpose of this prospective, randomized study was to compare RMN with manually guided catheter ablation for AV nodal reentrant tachycardia (AVNRT) regarding fluoroscopy time/dosage, acute and long-term efficacy as well as safety. A total of 218 patients with AVNRT undergoing catheter ablation at three centers (male 34%, mean age 50 ± 17 years) were randomized to a manual approach (n = 113) or RMN (n = 105) using the Niobe ® magnetic navigation system. The primary study endpoint was total fluoroscopy time/dosage for patient and operator at the end of the procedure. Secondary endpoints included acute success, procedure duration, complications and success rate after 6 months. Fluoroscopy time and dosage for the patient were significantly reduced in the RMN group compared to the manual group (6 ± 6 vs. 11 ± 10 min; p < 0.001 and 425 ± 558 vs. 751 ± 900 cGycm 2 , p = 0.002). A reduction in fluoroscopy time/dose also applied to the operator (3 ± 5 vs. 7 ± 9 min 209 ± 444 vs. 482 ± 689 cGycm 2 , p < 0.001). Procedure duration was significantly longer in the RMN group (88 ± 29 vs. 79 ± 29 min; p = 0.03) and crossover from the RMN group to manual ablation occurred in 7.6% of patients (7.6 vs. 0.1%; p = 0.02). Acute success was achieved in 100% of patients in both groups. Midterm success after 6 months was 97 vs. 98% (p = 0.67). No complications occurred in both groups. The use of RMN for catheter ablation of AVNRT compared to a manual approach results in a reduction of fluoroscopy time and dosage of about 50% for both patients and physicians. Acute and midterm success and safety are comparable. RMN is a good alternative to a manual approach for AVNRT ablation.

Organ dose assessment in pediatric fluoroscopy and CT via a tomographic computational phantom of the newborn patient

NASA Astrophysics Data System (ADS)

Staton, Robert J.

Of the various types of imaging modalities used in pediatric radiology, fluoroscopy and computed tomography (CT) have the highest associated radiation dose. While these examinations are commonly used for pediatric patients, little data exists on the magnitude of the organ and effective dose values for these procedures. Calculation of these dose values is necessary because of children's increased sensitivity to radiation and their long life expectancy for which to express radiation's latent effects. In this study, a newborn tomographic phantom has been implemented in a radiation transport code to evaluate organ and effective doses for newborn patients in commonly performed fluoroscopy and CT examinations. Organ doses were evaluated for voiding cystourethrogram (VCUG) fluoroscopy studies of infant patients. Time-sequence analysis was performed for videotaped VCUG studies of five different patients. Organ dose values were then estimated for each patient through Monte Carlo (MC) simulations. The effective dose values of the VCUG examination for five patients ranged from 0.6 mSv to 3.2 mSv, with a mean of 1.8 +/- 0.9 mSv. Organ doses were also assessed for infant upper gastrointestinal (UGI) fluoroscopy exams. The effective dose values of the UGI examinations for five patients ranged from 1.05 mSv to 5.92 mSv, with a mean of 2.90 +/- 1.97 mSv. MC simulations of helical multislice CT (MSCT) exams were also completed using, the newborn tomographic phantom and a stylized newborn phantom. The helical path of the source, beam shaping filter, beam profile, patient table, were all included in the MC simulations of the helical MSCT scanner. Organ doses and effective doses and their dependence on scan parameters were evaluated for newborn patients. For all CT scans, the effective dose was found to range approximately 1-13 mSv, with the largest values occurring for CAP scans. Tube current modulation strategies to reduce patient dose were also evaluated for newborn patients. Overall, utilization of the newborn tomographic phantom in MC simulations has shown the need for and usefulness of pediatric tomographic phantoms. The newborn tomographic model has shown more versatility and realistic anatomical modeling when compared to the existing stylized newborn phantom. This work has provided important organ dose data for infant patients in common examinations in pediatric radiology.

Monte Carlo based estimation of organ and effective doses to patients undergoing hysterosalpingography and retrograde urethrography fluoroscopy procedures

NASA Astrophysics Data System (ADS)

Ngaile, J. E.; Msaki, P. K.; Kazema, R. R.

2018-04-01

Contrast investigations of hysterosalpingography (HSG) and retrograde urethrography (RUG) fluoroscopy procedures remain the dominant diagnostic tools for the investigation of infertility in females and urethral strictures in males, respectively, owing to the scarcity and high cost of services of alternative diagnostic technologies. In light of the radiological risks associated with contrast based investigations of the genitourinary tract systems, there is a need to assess the magnitude of radiation burden imparted to patients undergoing HSG and RUG fluoroscopy procedures in Tanzania. The air kerma area product (KAP), fluoroscopy time, number of images, organ dose and effective dose to patients undergoing HSG and RUG procedures were obtained from four hospitals. The KAP was measured using a flat transmission ionization chamber, while the organ and effective doses were estimated using the knowledge of the patient characteristics, patient related exposure parameters, geometry of examination, KAP and Monte Carlo calculations (PCXMC). The median values of KAP for the HSG and RUG were 2.2 Gy cm2 and 3.3 Gy cm2, respectively. The median organ doses in the present study for the ovaries, urinary bladder and uterus for the HSG procedures, were 1.0 mGy, 4.0 mGy and 1.6 mGy, respectively, while for urinary bladder and testes of the RUG were 3.4 mGy and 5.9 mGy, respectively. The median values of effective doses for the HSG and RUG procedures were 0.65 mSv and 0.59 mSv, respectively. The median values of effective dose per hospital for the HSG and RUG procedures had a range of 1.6-2.8 mSv and 1.9-5.6 mSv, respectively, while the overall differences between individual effective doses across the four hospitals varied by factors of up to 22.0 and 46.7, respectively for the HSG and RUG procedures. The proposed diagnostic reference levels (DRLs) for the HSG and RUG were for KAP 2.8 Gy cm2 and 3.9 Gy cm2, for fluoroscopy time 0.8 min and 0.9 min, and for number of images 5 and 4, respectively. The suggested DRLs for the HSG and RUG procedures may be used by the radiology departments in Tanzania for management of attained dose levels until the national DRLs are established.

Depth-resolved registration of transesophageal echo to x-ray fluoroscopy using an inverse geometry fluoroscopy system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hatt, Charles R.; Tomkowiak, Michael T.; Dunkerley, David A. P.

2015-12-15

Purpose: Image registration between standard x-ray fluoroscopy and transesophageal echocardiography (TEE) has recently been proposed. Scanning-beam digital x-ray (SBDX) is an inverse geometry fluoroscopy system designed for cardiac procedures. This study presents a method for 3D registration of SBDX and TEE images based on the tomosynthesis and 3D tracking capabilities of SBDX. Methods: The registration algorithm utilizes the stack of tomosynthetic planes produced by the SBDX system to estimate the physical 3D coordinates of salient key-points on the TEE probe. The key-points are used to arrive at an initial estimate of the probe pose, which is then refined using amore » 2D/3D registration method adapted for inverse geometry fluoroscopy. A phantom study was conducted to evaluate probe pose estimation accuracy relative to the ground truth, as defined by a set of coregistered fiducial markers. This experiment was conducted with varying probe poses and levels of signal difference-to-noise ratio (SDNR). Additional phantom and in vivo studies were performed to evaluate the correspondence of catheter tip positions in TEE and x-ray images following registration of the two modalities. Results: Target registration error (TRE) was used to characterize both pose estimation and registration accuracy. In the study of pose estimation accuracy, successful pose estimates (3D TRE < 5.0 mm) were obtained in 97% of cases when the SDNR was 5.9 or higher in seven out of eight poses. Under these conditions, 3D TRE was 2.32 ± 1.88 mm, and 2D (projection) TRE was 1.61 ± 1.36 mm. Probe localization error along the source-detector axis was 0.87 ± 1.31 mm. For the in vivo experiments, mean 3D TRE ranged from 2.6 to 4.6 mm and mean 2D TRE ranged from 1.1 to 1.6 mm. Anatomy extracted from the echo images appeared well aligned when projected onto the SBDX images. Conclusions: Full 6 DOF image registration between SBDX and TEE is feasible and accurate to within 5 mm. Future studies will focus on real-time implementation and application-specific analysis.« less

Predicting the difficulty of a lead extraction procedure: the LED index.

PubMed

Bontempi, Luca; Vassanelli, Francesca; Cerini, Manuel; D'Aloia, Antonio; Vizzardi, Enrico; Gargaro, Alessio; Chiusso, Francesco; Mamedouv, Rashad; Lipari, Alessandro; Curnis, Antonio

2014-08-01

According to recent surveys, many sites performing permanent lead extractions do not meet the minimum prerequisites concerning personnel training, procedures' volume, or facility requirements. The current Heart Rhythm Society consensus on lead extractions suggests that patients should be referred to more experienced sites when a better outcome could be achieved. The purpose of this study was to develop a score aimed at predicting the difficulty of a lead extraction procedure through the analysis of a high-volume center database. This score could help to discriminate patients who should be sent to a referral site. A total of 889 permanent leads were extracted from 469 patients. All procedures were performed from January 2009 to May 2012 by two expert electrophysiologists, at the University Hospital of Brescia. Factors influencing the difficulty of a procedure were assessed using a univariate and a multivariate logistic regression model. The fluoroscopy time of the procedure was taken as an index of difficulty. A Lead Extraction Difficulty (LED) score was defined, considering the strongest predictors. Overall, 873 of 889 (98.2%) leads were completely removed. Major complications were reported in one patient (0.2%) who manifested cardiac tamponade. Minor complications occurred in six (1.3%) patients. No deaths occurred. Median fluoroscopic time was 8.7 min (3.3-17.3). A procedure was classified as difficult when fluoroscopy time was more than 31.2 min [90th percentile (PCTL)].At a univariate analysis, the number of extracted leads and years from implant were significantly associated with an increased risk of fluoroscopy time above 90th PCTL [odds ratio (OR) 1.51, 95% confidence interval (CI) 1.08-2.11, P = 0.01; and OR 1.19, 95% CI 1.12-1.25, P < 0.001, respectively). After adjusting for patient age and sex, and combining with other covariates potentially influencing the extraction procedure, a multivariate analysis confirmed a 71% increased risk of fluoroscopy time above 90th PCTL for each additional lead extracted (OR 1.71, 95% CI 1.06-2.77, P = 0.028) and a 23% increased risk for each year of lead age (OR 1.23, 95% CI 1.15-1.31, P < 0.001). Further nonindependent factors increasing the risk were the presence of active fixation leads and dual-coil implantable cardiac defibrillator leads. Conversely, vegetations significantly favored lead extraction.The LED score was defined as: number of extracted leads within a procedure + lead age (years from implant) + 1 if dual-coil - 1 if vegetation. The LED score independently predicted complex procedure (with fluoroscopic time >90th PCTL) both at univariate and multivariate analysis. A receiver-operating characteristic analysis showed an area under the curve of 0.81. A LED score greater than 10 could predict fluoroscopy time above 90th PCTL with a sensitivity of 78.3% and a specificity of 76.7%. The LED score is easy to compute and potentially predicts fluoroscopy time above 90th PCTL with a relatively high accuracy.

Maximum voltage gradient technique for optimization of ablation for typical atrial flutter with zero-fluoroscopy approach

PubMed Central

Deutsch, Karol; Śledź, Janusz; Mazij, Mariusz; Ludwik, Bartosz; Labus, Michał; Karbarz, Dariusz; Pasicka, Bernadetta; Chrabąszcz, Michał; Śledź, Arkadiusz; Klank-Szafran, Monika; Vitali-Sendoz, Laura; Kameczura, Tomasz; Śpikowski, Jerzy; Stec, Piotr; Ujda, Marek; Stec, Sebastian

2017-01-01

Abstract Radiofrequency catheter ablation (RFCA) is an established effective method for the treatment of typical cavo-tricuspid isthmus (CTI)-dependent atrial flutter (AFL). The introduction of 3-dimensional electro-anatomic systems enables RFCA without fluoroscopy (No-X-Ray [NXR]). The aim of this study was to evaluate the feasibility and effectiveness of CTI RFCA during implementation of the NXR approach and the maximum voltage-guided (MVG) technique for ablation of AFL. Data were obtained from prospective standardized multicenter ablation registry. Consecutive patients with the first RFCA for CTI-dependent AFL were recruited. Two navigation approaches (NXR and fluoroscopy based as low as reasonable achievable [ALARA]) and 2 mapping and ablation techniques (MVG and pull-back technique [PBT]) were assessed. NXR + MVG (n  =  164; age: 63.7 ± 9.5; 30% women), NXR + PBT (n  =  55; age: 63.9 ± 10.7; 39% women); ALARA + MVG (n  =  36; age: 64.2 ± 9.6; 39% women); and ALARA + PBT (n  =  205; age: 64.7 ± 9.1; 30% women) were compared, respectively. All groups were simplified with a 2-catheter femoral approach using 8-mm gold tip catheters (Osypka AG, Germany or Biotronik, Germany) with 15 min of observation. The MVG technique was performed using step-by-step application by mapping the largest atrial signals within the CTI. Bidirectional block in CTI was achieved in 99% of all patients (P  =  NS, between groups). In NXR + MVG and NXR + PBT groups, the procedure time decreased (45.4 ± 17.6 and 47.2 ± 15.7 min vs. 52.6 ± 23.7 and 59.8 ± 24.0 min, P < .01) as compared to ALARA + MVG and ALARA + PBT subgroups. In NXR + MVG and NXR + PBT groups, 91% and 98% of the procedures were performed with complete elimination of fluoroscopy. The NXR approach was associated with a significant reduction in fluoroscopy exposure (from 0.2 ± 1.1 [NXR + PBT] and 0.3 ± 1.6 [NXR + MVG] to 7.7 ± 6.0 min [ALARA + MVG] and 9.1 ± 7.2 min [ALARA + PBT], P < .001). The total application time significantly decreased in the MVG technique subgroup both in NXR and ALARA (P < .01). No major complications were observed in either groups. Complete elimination of fluoroscopy is feasible, safe, and effective during RFCA of CTI in almost all AFL patients without cardiac implanted electronic devices. The most optimal method for RFCA of CTI-dependent AFL seems to be MVG; however, it required validation of optimal RFCA's parameters with clinical follow-up. PMID:28640075

Maximum voltage gradient technique for optimization of ablation for typical atrial flutter with zero-fluoroscopy approach.

PubMed

Deutsch, Karol; Śledź, Janusz; Mazij, Mariusz; Ludwik, Bartosz; Labus, Michał; Karbarz, Dariusz; Pasicka, Bernadetta; Chrabąszcz, Michał; Śledź, Arkadiusz; Klank-Szafran, Monika; Vitali-Sendoz, Laura; Kameczura, Tomasz; Śpikowski, Jerzy; Stec, Piotr; Ujda, Marek; Stec, Sebastian

2017-06-01

Radiofrequency catheter ablation (RFCA) is an established effective method for the treatment of typical cavo-tricuspid isthmus (CTI)-dependent atrial flutter (AFL). The introduction of 3-dimensional electro-anatomic systems enables RFCA without fluoroscopy (No-X-Ray [NXR]). The aim of this study was to evaluate the feasibility and effectiveness of CTI RFCA during implementation of the NXR approach and the maximum voltage-guided (MVG) technique for ablation of AFL.Data were obtained from prospective standardized multicenter ablation registry. Consecutive patients with the first RFCA for CTI-dependent AFL were recruited. Two navigation approaches (NXR and fluoroscopy based as low as reasonable achievable [ALARA]) and 2 mapping and ablation techniques (MVG and pull-back technique [PBT]) were assessed. NXR + MVG (n  =  164; age: 63.7 ± 9.5; 30% women), NXR + PBT (n  =  55; age: 63.9 ± 10.7; 39% women); ALARA + MVG (n  =  36; age: 64.2 ± 9.6; 39% women); and ALARA + PBT (n  =  205; age: 64.7 ± 9.1; 30% women) were compared, respectively. All groups were simplified with a 2-catheter femoral approach using 8-mm gold tip catheters (Osypka AG, Germany or Biotronik, Germany) with 15 min of observation. The MVG technique was performed using step-by-step application by mapping the largest atrial signals within the CTI.Bidirectional block in CTI was achieved in 99% of all patients (P  =  NS, between groups). In NXR + MVG and NXR + PBT groups, the procedure time decreased (45.4 ± 17.6 and 47.2 ± 15.7 min vs. 52.6 ± 23.7 and 59.8 ± 24.0 min, P < .01) as compared to ALARA + MVG and ALARA + PBT subgroups. In NXR + MVG and NXR + PBT groups, 91% and 98% of the procedures were performed with complete elimination of fluoroscopy. The NXR approach was associated with a significant reduction in fluoroscopy exposure (from 0.2 ± 1.1 [NXR + PBT] and 0.3 ± 1.6 [NXR + MVG] to 7.7 ± 6.0 min [ALARA + MVG] and 9.1 ± 7.2 min [ALARA + PBT], P < .001). The total application time significantly decreased in the MVG technique subgroup both in NXR and ALARA (P < .01). No major complications were observed in either groups.Complete elimination of fluoroscopy is feasible, safe, and effective during RFCA of CTI in almost all AFL patients without cardiac implanted electronic devices. The most optimal method for RFCA of CTI-dependent AFL seems to be MVG; however, it required validation of optimal RFCA's parameters with clinical follow-up.

Stent deployment protocol for optimized real-time visualization during endovascular neurosurgery.

PubMed

Silva, Michael A; See, Alfred P; Dasenbrock, Hormuzdiyar H; Ashour, Ramsey; Khandelwal, Priyank; Patel, Nirav J; Frerichs, Kai U; Aziz-Sultan, Mohammad A

2017-05-01

Successful application of endovascular neurosurgery depends on high-quality imaging to define the pathology and the devices as they are being deployed. This is especially challenging in the treatment of complex cases, particularly in proximity to the skull base or in patients who have undergone prior endovascular treatment. The authors sought to optimize real-time image guidance using a simple algorithm that can be applied to any existing fluoroscopy system. Exposure management (exposure level, pulse management) and image post-processing parameters (edge enhancement) were modified from traditional fluoroscopy to improve visualization of device position and material density during deployment. Examples include the deployment of coils in small aneurysms, coils in giant aneurysms, the Pipeline embolization device (PED), the Woven EndoBridge (WEB) device, and carotid artery stents. The authors report on the development of the protocol and their experience using representative cases. The stent deployment protocol is an image capture and post-processing algorithm that can be applied to existing fluoroscopy systems to improve real-time visualization of device deployment without hardware modifications. Improved image guidance facilitates aneurysm coil packing and proper positioning and deployment of carotid artery stents, flow diverters, and the WEB device, especially in the context of complex anatomy and an obscured field of view.

Comparison of suprapatellar and infrapatellar intramedullary nailing for tibial shaft fractures: a systematic review and meta-analysis.

PubMed

Yang, Liqing; Sun, Yuefeng; Li, Ge

2018-06-14

Optimal surgical approach for tibial shaft fractures remains controversial. We perform a meta-analysis from randomized controlled trials (RCTs) to compare the clinical efficacy and prognosis between infrapatellar and suprapatellar intramedullary nail in the treatment of tibial shaft fractures. PubMed, OVID, Embase, ScienceDirect, and Web of Science were searched up to December 2017 for comparative RCTs involving infrapatellar and suprapatellar intramedullary nail in the treatment of tibial shaft fractures. Primary outcomes were blood loss, visual analog scale (VAS) score, range of motion, Lysholm knee scores, and fluoroscopy times. Secondary outcomes were length of hospital stay and postoperative complications. We assessed statistical heterogeneity for each outcome with the use of a standard χ 2 test and the I 2 statistic. The meta-analysis was undertaken using Stata 14.0. Four RCTs involving 293 participants were included in our study. The present meta-analysis indicated that there were significant differences between infrapatellar and suprapatellar intramedullary nail regarding the total blood loss, VAS scores, Lysholm knee scores, and fluoroscopy times. Suprapatellar intramedullary nailing could significantly reduce total blood loss, postoperative knee pain, and fluoroscopy times compared to infrapatellar approach. Additionally, it was associated with an improved Lysholm knee scores. High-quality RCTs were still required for further investigation.

Arbitrary shape region-of-interest fluoroscopy system

NASA Astrophysics Data System (ADS)

Xu, Tong; Le, Huy; Molloi, Sabee Y.

2002-05-01

Region-of-interest (ROI) fluoroscopy has previously been investigated as a method to reduce x-ray exposure to the patient and the operator. This ROI fluoroscopy technique allows the operator to arbitrarily determine the shape, size, and location of the ROI. A device was used to generate patient specific x-ray beam filters. The device is comprised of 18 step-motors that control a 16 X 16 matrix of pistons to form the filter from a deformable attenuating material. Patient exposure reductions were measured to be 84 percent for a 65 kVp beam. Operator exposure reduction was measured to be 69 percent. Due to the reduced x-ray scatter, image contrast was improved by 23 percent inside the ROI. The reduced gray level in the periphery was corrected using an experimentally determined compensation ratio. A running average interpolation technique was used to eliminate the artifacts from the ROI edge. As expected, the final corrected images show increased noise in the periphery. However, the anatomical structures in the periphery could still be visualized. This arbitrary shaped region of interest fluoroscopic technique was shown to be effective in terms of its ability to reduce patient and operator exposure without significant reduction in image quality. The ability to define an arbitrary shaped ROI should make the technique more clinically feasible.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bargellini, Irene, E-mail: irenebargellini@hotmail.com; Turini, Francesca; Bozzi, Elena

To assess feasibility of proper hepatic artery catheterization using a 3D model obtained from preprocedural computed tomographic angiography (CTA), fused with real-time fluoroscopy, during transarterial chemoembolization of hepatocellular carcinoma. Twenty consecutive cirrhotic patients with hepatocellular carcinoma undergoing transarterial chemoembolization were prospectively enrolled onto the study. The early arterial phase axial images of the preprocedural CTA were postprocessed on an independent workstation connected to the angiographic system (Innova 4100; GE Healthcare, Milwaukee, WI), obtaining a 3D volume rendering image (VR) that included abdominal aorta, splanchnic arteries, and first and second lumbar vertebrae. The VR image was manually registered to the real-timemore » X-ray fluoroscopy, with the lumbar spine used as the reference. The VR image was then used as guidance to selectively catheterize the proper hepatic artery. The procedure was considered successful when performed with no need for intraarterial contrast injections or angiographic acquisitions. The procedure was successful in 19 (95 %) of 20 patients. In one patient, celiac trunk angiography was required for the presence of a significant ostial stenosis that was underestimated at computed tomography. Time for image reconstruction and registration was <10 min in all cases. The use of preprocedural CTA model with fluoroscopy enables confident and direct catheterization of the proper hepatic artery with no need for preliminary celiac trunk angiography, thus reducing radiation exposure and contrast media administration.« less

Detection and correction of patient movement in prostate brachytherapy seed reconstruction

NASA Astrophysics Data System (ADS)

Lam, Steve T.; Cho, Paul S.; Marks, Robert J., II; Narayanan, Sreeram

2005-05-01

Intraoperative dosimetry of prostate brachytherapy can help optimize the dose distribution and potentially improve clinical outcome. Evaluation of dose distribution during the seed implant procedure requires the knowledge of 3D seed coordinates. Fluoroscopy-based seed localization is a viable option. From three x-ray projections obtained at different gantry angles, 3D seed positions can be determined. However, when local anaesthesia is used for prostate brachytherapy, the patient movement during fluoroscopy image capture becomes a practical problem. If uncorrected, the errors introduced by patient motion between image captures would cause seed mismatches. Subsequently, the seed reconstruction algorithm would either fail to reconstruct or yield erroneous results. We have developed an algorithm that permits detection and correction of patient movement that may occur between fluoroscopy image captures. The patient movement is decomposed into translational shifts along the tabletop and rotation about an axis perpendicular to the tabletop. The property of spatial invariance of the co-planar imaging geometry is used for lateral movement correction. Cranio-caudal movement is corrected by analysing the perspective invariance along the x-ray axis. Rotation is estimated by an iterative method. The method can detect and correct for the range of patient movement commonly seen in the clinical environment. The algorithm has been implemented for routine clinical use as the preprocessing step for seed reconstruction.

Remote magnetic navigation for mapping and ablating right ventricular outflow tract tachycardia.

PubMed

Thornton, Andrew S; Jordaens, Luc J

2006-06-01

Navigation, mapping, and ablation in the right ventricular outflow tract (RVOT) can be difficult. Catheter navigation using external magnetic fields may allow more accurate mapping and ablation. The purpose of this study was to assess the feasibility of RVOT tachycardia ablation using remote magnetic navigation. Mapping and ablation were performed in eight patients with outflow tract ventricular arrhythmias. Tachycardia mapping was undertaken with a 64-polar basket catheter, followed by remote activation and pace-mapping using a magnetically enabled catheter. The area of interest was localized on the basket catheter in seven patients in whom an RVOT arrhythmia was identified. Remote navigation of the magnetic catheter to this area was followed by pace-mapping. Ablation was performed at the site of perfect pace-mapping, with earliest activation if possible. Acute success was achieved in all patients (median four applications). Median procedural time was 144 minutes, with 13.4 minutes of patient fluoroscopy time and 3.8 minutes of physician fluoroscopy time. No complications occurred. One recurrence occurred during follow-up (mean 366 days). RVOT tachycardias can be mapped and ablated using remote magnetic navigation, initially guided by a basket catheter. Precise activation and pace-mapping are possible. Remote magnetic navigation permitted low fluoroscopy exposure for the physician. Long-term results are promising.

Radiation Exposure of Interventional Radiologists During Computed Tomography Fluoroscopy-Guided Renal Cryoablation and Lung Radiofrequency Ablation: Direct Measurement in a Clinical Setting.

PubMed

Matsui, Yusuke; Hiraki, Takao; Gobara, Hideo; Iguchi, Toshihiro; Fujiwara, Hiroyasu; Kawabata, Takahiro; Yamauchi, Takatsugu; Yamaguchi, Takuya; Kanazawa, Susumu

2016-06-01

Computed tomography (CT) fluoroscopy-guided renal cryoablation and lung radiofrequency ablation (RFA) have received increasing attention as promising cancer therapies. Although radiation exposure of interventional radiologists during these procedures is an important concern, data on operator exposure are lacking. Radiation dose to interventional radiologists during CT fluoroscopy-guided renal cryoablation (n = 20) and lung RFA (n = 20) was measured prospectively in a clinical setting. Effective dose to the operator was calculated from the 1-cm dose equivalent measured on the neck outside the lead apron, and on the left chest inside the lead apron, using electronic dosimeters. Equivalent dose to the operator's finger skin was measured using thermoluminescent dosimeter rings. The mean (median) effective dose to the operator per procedure was 6.05 (4.52) μSv during renal cryoablation and 0.74 (0.55) μSv during lung RFA. The mean (median) equivalent dose to the operator's finger skin per procedure was 2.1 (2.1) mSv during renal cryoablation, and 0.3 (0.3) mSv during lung RFA. Radiation dose to interventional radiologists during renal cryoablation and lung RFA were at an acceptable level, and in line with recommended dose limits for occupational radiation exposure.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ierardi, Anna Maria; Duka, Ejona; Radaelli, Alessandro

AimTo evaluate the feasibility of image fusion (IF) of pre-procedural arterial-phase CT angiography or MR angiography with intra-procedural fluoroscopy for road-mapping in endovascular treatment of aorto-iliac steno-occlusive disease.Materials and MethodsBetween September and November, 2014, we prospectively evaluated 5 patients with chronic aorto-iliac steno-occlusive disease, who underwent endovascular treatment in the angiography suite. Fusion image road-mapping was performed using angiographic phase CT images or MR images acquired before and intra-procedural unenhanced cone-beam CT. Radiation dose of the procedure, volume of intra-procedural iodinated contrast medium, fluoroscopy time, and overall procedural time were recorded. Reasons for potential fusion imaging inaccuracies were also evaluated.ResultsImagemore » co-registration and fusion guidance were feasible in all procedures. Mean radiation dose of the procedure was 60.21 Gycm2 (range 55.02–63.75 Gycm2). The mean total procedure time was 32.2 min (range 27–38 min). The mean fluoroscopy time was 12 min and 3 s. The mean procedural iodinated contrast material dose was 24 mL (range 20–40 mL).ConclusionsIF gives Interventional Radiologists the opportunity to use new technologies in order to improve outcomes with a significant reduction of contrast media administration.« less

Unique migration of a dental needle into the parapharyngeal space: successful removal by an intraoral approach and simulation for tracking visibility in X-ray fluoroscopy.

PubMed

Okumura, Yuri; Hidaka, Hiroshi; Seiji, Kazumasa; Nomura, Kazuhiro; Takata, Yusuke; Suzuki, Takahiro; Katori, Yukio

2015-02-01

The first objective was to describe a novel case of migration of a broken dental needle into the parapharyngeal space. The second was to address the importance of simulation elucidating visualization of such a thin needle under X-ray fluoroscopy. Clinical case records (including computed tomography [CT] and surgical approaches) were reviewed, and a simulation experiment using a head phantom was conducted using the same settings applied intraoperatively. A 36-year-old man was referred after failure to locate a broken 31-G dental needle. Computed tomography revealed migration of the needle into the parapharyngeal space. Intraoperative X-ray fluoroscopy failed to identify the needle, so a steel wire was applied as a reference during X-ray to locate the foreign body. The needle was successfully removed using an intraoral approach with tonsillectomy under surgical microscopy. The simulation showed that the dental needle was able to be identified only after applying an appropriate compensating filter, contrasting with the steel wire. Meticulous preoperative simulation regarding visual identification of dental needle foreign bodies is mandatory. Intraoperative radiography and an intraoral approach with tonsillectomy under surgical microscopy offer benefits for accessing the parapharyngeal space, specifically for cases medial to the great vessels. © The Author(s) 2014.

Pulmonary Masses: Initial Results of Cone-beam CT Guidance with Needle Planning Software for Percutaneous Lung Biopsy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Braak, Sicco J., E-mail: sjbraak@gmail.com; Herder, Gerarda J. M., E-mail: j.herder@antoniusziekenhuis.nl; Heesewijk, Johannes P. M. van, E-mail: j.heesewijk@antoniusziekenhuis.nl

2012-12-15

Purpose: To evaluate the outcome of percutaneous lung biopsy (PLB) findings using cone-beam computed tomographic (CT) guidance (CBCT guidance) and compared to conventional biopsy guidance techniques. Methods: CBCT guidance is a stereotactic technique for needle interventions, combining 3D soft-tissue cone-beam CT, needle planning software, and real-time fluoroscopy. Between March 2007 and August 2010, we performed 84 Tru-Cut PLBs, where bronchoscopy did not provide histopathologic diagnosis. Mean patient age was 64.6 (range 24-85) years; 57 patients were men, and 25 were women. Records were prospectively collected for calculating sensitivity, specificity, positive predictive value, negative predictive value, and accuracy. We also registeredmore » fluoroscopy time, room time, interventional time, dose-area product (DAP), and complications. Procedures were divided into subgroups (e.g., location, size, operator). Results: Mean lesion diameter was 32.5 (range 3.0-93.0) mm, and the mean number of samples per biopsy procedure was 3.2 (range 1-7). Mean fluoroscopy time was 161 (range 104-551) s, room time was 34 (range 15-79) min, mean DAP value was 25.9 (range 3.9-80.5) Gy{center_dot}cm{sup -2}, and interventional time was 18 (range 5-65) min. Of 84 lesions, 70 were malignant (83.3%) and 14 were benign (16.7%). Seven (8.3%) of the biopsy samples were nondiagnostic. All nondiagnostic biopsied lesions proved to be malignant during surgical resection. The outcome for sensitivity, specificity, positive predictive value, negative predictive value, and accuracy was 90% (95% confidence interval [CI] 86-96), 100% (95% CI 82-100), 100% (95% CI 96-100), 66.7% (95% CI 55-83), and 91.7% (95% CI 86-96), respectively. Sixteen patients (19%) had minor and 2 (2.4%) had major complications. Conclusion: CBCT guidance is an effective method for PLB, with results comparable to CT/CT fluoroscopy guidance.« less

Evaluation of RSA set-up from a clinical biplane fluoroscopy system for 3D joint kinematic analysis.

PubMed

Bonanzinga, Tommaso; Signorelli, Cecilia; Bontempi, Marco; Russo, Alessandro; Zaffagnini, Stefano; Marcacci, Maurilio; Bragonzoni, Laura

2016-01-01

dinamic roentgen stereophotogrammetric analysis (RSA), a technique currently based only on customized radiographic equipment, has been shown to be a very accurate method for detecting three-dimensional (3D) joint motion. The aim of the present work was to evaluate the applicability of an innovative RSA set-up for in vivo knee kinematic analysis, using a biplane fluoroscopic image system. To this end, the Authors describe the set-up as well as a possible protocol for clinical knee joint evaluation. The accuracy of the kinematic measurements is assessed. the Authors evaluated the accuracy of 3D kinematic analysis of the knee in a new RSA set-up, based on a commercial biplane fluoroscopy system integrated into the clinical environment. The study was organized in three main phases: an in vitro test under static conditions, an in vitro test under dynamic conditions reproducing a flexion-extension range of motion (ROM), and an in vivo analysis of the flexion-extension ROM. For each test, the following were calculated, as an indication of the tracking accuracy: mean, minimum, maximum values and standard deviation of the error of rigid body fitting. in terms of rigid body fitting, in vivo test errors were found to be 0.10±0.05 mm. Phantom tests in static and kinematic conditions showed precision levels, for translations and rotations, of below 0.1 mm/0.2° and below 0.5 mm/0.3° respectively for all directions. the results of this study suggest that kinematic RSA can be successfully performed using a standard clinical biplane fluoroscopy system for the acquisition of slow movements of the lower limb. a kinematic RSA set-up using a clinical biplane fluoroscopy system is potentially applicable and provides a useful method for obtaining better characterization of joint biomechanics.

Comparison of measured and estimated maximum skin doses during CT fluoroscopy lung biopsies.

PubMed

Zanca, F; Jacobs, A; Crijns, W; De Wever, W

2014-07-01

To measure patient-specific maximum skin dose (MSD) associated with CT fluoroscopy (CTF) lung biopsies and to compare measured MSD with the MSD estimated from phantom measurements, as well as with the CTDIvol of patient examinations. Data from 50 patients with lung lesions who underwent a CT fluoroscopy-guided biopsy were collected. The CT protocol consisted of a low-kilovoltage (80 kV) protocol used in combination with an algorithm for dose reduction to the radiology staff during the interventional procedure, HandCare (HC). MSD was assessed during each intervention using EBT2 gafchromic films positioned on patient skin. Lesion size, position, total fluoroscopy time, and patient-effective diameter were registered for each patient. Dose rates were also estimated at the surface of a normal-size anthropomorphic thorax phantom using a 10 cm pencil ionization chamber placed at every 30°, for a full rotation, with and without HC. Measured MSD was compared with MSD values estimated from the phantom measurements and with the cumulative CTDIvol of the procedure. The median measured MSD was 141 mGy (range 38-410 mGy) while the median cumulative CTDIvol was 72 mGy (range 24-262 mGy). The ratio between the MSD estimated from phantom measurements and the measured MSD was 0.87 (range 0.12-4.1) on average. In 72% of cases the estimated MSD underestimated the measured MSD, while in 28% of the cases it overestimated it. The same trend was observed for the ratio of cumulative CTDIvol and measured MSD. No trend was observed as a function of patient size. On average, estimated MSD from dose rate measurements on phantom as well as from CTDIvol of patient examinations underestimates the measured value of MSD. This can be attributed to deviations of the patient's body habitus from the standard phantom size and to patient positioning in the gantry during the procedure.

Comparison Perioperative Factors During Minimally Invasive Pre-Psoas Lateral Interbody Fusion of the Lumbar Spine Using Either Navigation or Conventional Fluoroscopy

PubMed Central

Zhang, Yue-Hui; White, Ian; Potts, Eric; Mobasser, Jean-Pierre

2017-01-01

Study Design: Retrospective clinical study. Objectives: The aim of this study was to compare intraoperative conditions and clinical results of patients undergoing pre-psoas oblique lateral interbody fusion (OLIF) using navigation or conventional fluoroscopy (C-ARM) techniques. Methods: Forty-two patients (22 patients by navigation and 20 by fluoroscopy) underwent the OLIF procedure at 2 medical centers, and records were reviewed. Clinical data was collected and compared between the 2 groups. Patients were followed-up with a range of 6 to 24 months. Results: There were no significant differences on demographic data between groups. The navigation group had zero radiation exposure (RE) to the surgeon and radiation time compared to the C-ARM group, with total RE of 44.59 ± 26.65 mGy and radiation time of 88.30 ± 58.28 seconds (P < .05). The RE to the patient was significantly lower in the O-ARM group (9.38 mGy) compared to the C-ARM group (44.59 ± 26.65 mGy). Operating room time was slightly longer in the navigation group (2.49 ± 1.35 hours) compared to the C-ARM group (2.30 ± 1.17 hours; P > .05), although not statistically significant. No differences were found in estimated blood loss, length of hospitalization, surgery-related complications, and outcome scores with an average of 8-month follow-up. Conclusions: Compared with C-ARM techniques, using navigation can eliminate RE to surgeon and decrease RE to the patient, and it had no significant effect on operating time, estimated blood loss, length of hospitalization, or perioperative complications in the patients with OLIF procedure. This study shows that navigation is a safe alternative to fluoroscopy during the OLIF procedure in the treatment of degenerative lumbar conditions. PMID:28989845

Differentiation of thrombus from pannus as the cause of acquired mechanical prosthetic heart valve obstruction by non-invasive imaging: a review of the literature.

PubMed

Tanis, Wilco; Habets, Jesse; van den Brink, Renee B A; Symersky, Petr; Budde, Ricardo P J; Chamuleau, Steven A J

2014-02-01

For acquired mechanical prosthetic heart valve (PHV) obstruction and suspicion on thrombosis, recently updated European Society of Cardiology guidelines advocate the confirmation of thrombus by transthoracic echocardiography, transesophageal echocardiography (TEE), and fluoroscopy. However, no evidence-based diagnostic algorithm is available for correct thrombus detection, although this is clinically important as fibrinolysis is contraindicated in non-thrombotic obstruction (isolated pannus). Here, we performed a review of the literature in order to propose a diagnostic algorithm. We performed a systematic search in Pubmed and Embase. Included publications were assessed on methodological quality based on the validated Quality Assessment of Diagnostic Accuracy Studies (QUADAS) II checklist. Studies were scarce (n = 15) and the majority were of moderate methodological quality. In total, 238 mechanical PHV's with acquired obstruction and a reliable reference standard were included for the evaluation of the role of fluoroscopy, echocardiography, or multidetector-row computed tomography (MDCT). In acquired PHV obstruction caused by thrombosis, mass detection by TEE and leaflet restriction detected by fluoroscopy were observed in the majority of cases (96 and 100%, respectively). In contrast, in acquired PHV obstruction free of thrombosis (pannus), leaflet restriction detected by fluoroscopy was absent in some cases (17%) and mass detection by TEE was absent in the majority of cases (66%). In case of mass detection by TEE, predictors for obstructive thrombus masses (compared with pannus masses) were leaflet restriction, soft echo density, and increased mass length. In situations of inconclusive echocardiography, MDCT may correctly detect pannus/thrombus based on the morphological aspects and localization. In acquired mechanical PHV obstruction without leaflet restriction and absent mass on TEE, obstructive PHV thrombosis cannot be confirmed and consequently, fibrinolysis is not advised. Based on the literature search and our opinion, a diagnostic algorithm is provided to correctly identify non-thrombotic PHV obstruction, which is highly relevant in daily clinical practice.

SU-E-J-42: Motion Adaptive Image Filter for Low Dose X-Ray Fluoroscopy in the Real-Time Tumor-Tracking Radiotherapy System.

PubMed

Miyamoto, N; Ishikawa, M; Sutherland, K; Suzuki, R; Matsuura, T; Takao, S; Toramatsu, C; Nihongi, H; Shimizu, S; Onimaru, R; Umegaki, K; Shirato, H

2012-06-01

In the real-time tumor-tracking radiotherapy system, fiducial markers are detected by X-ray fluoroscopy. The fluoroscopic parameters should be optimized as low as possible in order to reduce unnecessary imaging dose. However, the fiducial markers could not be recognized due to effect of statistical noise in low dose imaging. Image processing is envisioned to be a solution to improve image quality and to maintain tracking accuracy. In this study, a recursive image filter adapted to target motion is proposed. A fluoroscopy system was used for the experiment. A spherical gold marker was used as a fiducial marker. About 450 fluoroscopic images of the marker were recorded. In order to mimic respiratory motion of the marker, the images were shifted sequentially. The tube voltage, current and exposure duration were fixed at 65 kV, 50 mA and 2.5 msec as low dose imaging condition, respectively. The tube current was 100 mA as high dose imaging. A pattern recognition score (PRS) ranging from 0 to 100 and image registration error were investigated by performing template pattern matching to each sequential image. The results with and without image processing were compared. In low dose imaging, theimage registration error and the PRS without the image processing were 2.15±1.21 pixel and 46.67±6.40, respectively. Those with the image processing were 1.48±0.82 pixel and 67.80±4.51, respectively. There was nosignificant difference in the image registration error and the PRS between the results of low dose imaging with the image processing and that of high dose imaging without the image processing. The results showed that the recursive filter was effective in order to maintain marker tracking stability and accuracy in low dose fluoroscopy. © 2012 American Association of Physicists in Medicine.

2D projection-based software application for mobile C-arms optimises wire placement in the proximal femur - An experimental study.

PubMed

Swartman, B; Frere, D; Wei, W; Schnetzke, M; Beisemann, N; Keil, H; Franke, J; Grützner, P A; Vetter, S Y

2017-10-01

A new software application can be used without fixed reference markers or a registration process in wire placement. The aim was to compare placement of Kirschner wires (K-wires) into the proximal femur with the software application versus the conventional method without guiding. As study hypothesis, we assumed less placement attempts, shorter procedure time and shorter fluoroscopy time using the software. The same precision inside a proximal femur bone model using the software application was premised. The software detects a K-wire within the 2D fluoroscopic image. By evaluating its direction and tip location, it superimposes a trajectory on the image, visualizing the intended direction of the K-wire. The K-wire was positioned in 20 artificial bones with the use of software by one surgeon; 20 bones served as conventional controls. A brass thumb tack was placed into the femoral head and its tip targeted with the wire. Number of placement attempts, duration of the procedure, duration of fluoroscopy time and distance to the target in a postoperative 3D scan were recorded. Compared with the conventional method, use of the application showed fewer attempts for optimal wire placement (p=0.026), shorter duration of surgery (p=0.004), shorter fluoroscopy time (p=0.024) and higher precision (p=0.018). Final wire position was achieved in the first attempt in 17 out of 20 cases with the software and in 9 out of 20 cases with the conventional method. The study hypothesis was confirmed. The new application optimised the process of K-wire placement in the proximal femur in an artificial bone model while also improving precision. Benefits lie especially in the reduction of placement attempts and reduction of fluoroscopy time under the aspect of radiation protection. The software runs on a conventional image intensifier and can therefore be easily integrated into the daily surgical routine. Copyright © 2017 Elsevier Ltd. All rights reserved.

Intervertebral anticollision constraints improve out-of-plane translation accuracy of a single-plane fluoroscopy-to-CT registration method for measuring spinal motion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, Cheng-Chung; Tsai, Tsung-Yuan; Hsu, Shih-Jung

2013-03-15

Purpose: The study aimed to propose a new single-plane fluoroscopy-to-CT registration method integrated with intervertebral anticollision constraints for measuring three-dimensional (3D) intervertebral kinematics of the spine; and to evaluate the performance of the method without anticollision and with three variations of the anticollision constraints via an in vitro experiment. Methods: The proposed fluoroscopy-to-CT registration approach, called the weighted edge-matching with anticollision (WEMAC) method, was based on the integration of geometrical anticollision constraints for adjacent vertebrae and the weighted edge-matching score (WEMS) method that matched the digitally reconstructed radiographs of the CT models of the vertebrae and the measured single-plane fluoroscopymore » images. Three variations of the anticollision constraints, namely, T-DOF, R-DOF, and A-DOF methods, were proposed. An in vitro experiment using four porcine cervical spines in different postures was performed to evaluate the performance of the WEMS and the WEMAC methods. Results: The WEMS method gave high precision and small bias in all components for both vertebral pose and intervertebral pose measurements, except for relatively large errors for the out-of-plane translation component. The WEMAC method successfully reduced the out-of-plane translation errors for intervertebral kinematic measurements while keeping the measurement accuracies for the other five degrees of freedom (DOF) more or less unaltered. The means (standard deviations) of the out-of-plane translational errors were less than -0.5 (0.6) and -0.3 (0.8) mm for the T-DOF method and the R-DOF method, respectively. Conclusions: The proposed single-plane fluoroscopy-to-CT registration method reduced the out-of-plane translation errors for intervertebral kinematic measurements while keeping the measurement accuracies for the other five DOF more or less unaltered. With the submillimeter and subdegree accuracy, the WEMAC method was considered accurate for measuring 3D intervertebral kinematics during various functional activities for research and clinical applications.« less

Value of Examination Under Fluoroscopy for the Assessment of Sacroiliac Joint Dysfunction.

PubMed

Eskander, Jonathan P; Ripoll, Juan G; Calixto, Frank; Beakley, Burton D; Baker, Jeffrey T; Healy, Patrick J; Gunduz, O H; Shi, Lizheng; Clodfelter, Jamie A; Liu, Jinan; Kaye, Alan D; Sharma, Sanjay

2015-01-01

Pain emanating from the sacroiliac (SI) joint can have variable radiation patterns. Single physical examination tests for SI joint pain are inconsistent with multiple tests increasing both sensitivity and specificity. To evaluate the use of fluoroscopy in the diagnosis of SI joint pain. Prospective double blind comparison study. Pain clinic and radiology setting in urban Veterans Administration (VA) in New Orleans, Louisiana. Twenty-two adult men, patients at a southeastern United States VA interventional pain clinic, presented with unilateral low back pain of more than 2 months' duration. Patients with previous back surgery were excluded from the study. Each patient was given a Gapping test, Patrick (FABERE) test, and Gaenslen test. A second blinded physician placed each patient prone under fluoroscopic guidance, asking each patient to point to the most painful area. Pain was provoked by applying pressure with the heel of the palm in that area to determine the point of maximum tenderness. The area was marked with a radio-opaque object and was placed on the mark with a fluoroscopic imgage. A site within 1 cm of the SI joint was considered as a positive test. This was followed by a diagnostic injection under fluoroscopy with 1 mL 2% lidocaine. A positive result was considered as more than 2 hours of greater than 75% reduction in pain. Then, in 2-3 days this was followed by a therapeutic injection under fluoroscopy with 1 mL 0.5% bupivacaine and 40 mg methylprednisolone. Each patient was reassessed after 6 weeks. The sensitivity and specificity in addition to the positive and negative predictive values were determined for both the conventional examinations, as well as the examination under fluoroscopy. Finally, a receiver operating characteristic (ROC) curve was constructed to evaluate test performance. The sensitivity and specificity of the fluoroscopic examination were 0.82 and 0.80 respectively; Positive predictive value and negative predictive value were 0.93 and 0.57 respectively. The area under ROC curve was 0.812 which is considered a "good" test; however the area under ROC for the conventional examination were between 0.52-0.58 which is considered "poor to fail". Variation in anatomy of the SI joint, small sample size. Multiple structures of the SI joint complex can result in clinical symptoms of pain. These include intra-articular structures (degenerative arthritis, and inflammatory conditions) as well as extra-articular structures (ligaments, muscles, etc.).

Magnetic resonance venography and three-dimensional image fusion guidance provide a novel paradigm for endovascular recanalization of chronic central venous occlusion.

PubMed

Schwein, Adeline; Lu, Tony; Chinnadurai, Ponraj; Kitkungvan, Danai; Shah, Dipan J; Chakfe, Nabil; Lumsden, Alan B; Bismuth, Jean

2017-01-01

Endovascular recanalization is considered first-line therapy for chronic central venous occlusion (CVO). Unlike arteries, in which landmarks such as wall calcifications provide indirect guidance for endovascular navigation, sclerotic veins without known vascular branching patterns impose significant challenges. Therefore, safe wire access through such chronic lesions mostly relies on intuition and experience. Studies have shown that magnetic resonance venography (MRV) can be performed safely in these patients, and the boundaries of occluded veins may be visualized on specific MRV sequences. Intraoperative image fusion techniques have become more common to guide complex arterial endovascular procedures. The aim of this study was to assess the feasibility and utility of MRV and intraoperative cone-beam computed tomography (CBCT) image fusion technique during endovascular CVO recanalization. During the study period, patients with symptomatic CVO and failed standard endovascular recanalization underwent further recanalization attempts with use of intraoperative MRV image fusion guidance. After preoperative MRV and intraoperative CBCT image coregistration, a virtual centerline path of the occluded segment was electronically marked in MRV and overlaid on real-time two-dimensional fluoroscopy images. Technical success, fluoroscopy times, radiation doses, number of venograms before recanalization, and accuracy of the virtual centerline overlay were evaluated. Four patients underwent endovascular CVO recanalization with use of intraoperative MRV image fusion guidance. Mean (± standard deviation) time for image fusion was 6:36 ± 00:51 mm:ss. The lesion was successfully crossed in all patients without complications. Mean fluoroscopy time for lesion crossing was 12.5 ± 3.4 minutes. Mean total fluoroscopy time was 28.8 ± 6.5 minutes. Mean total radiation dose was 15,185 ± 7747 μGy/m 2 , and mean radiation dose from CBCT acquisition was 2788 ± 458 μGy/m 2 (18% of mean total radiation dose). Mean number of venograms before recanalization was 1.6 ± 0.9, whereas two lesions were crossed without any prior venography. On qualitative analysis, virtual centerlines from MRV were aligned with actual guidewire trajectory on fluoroscopy in all four cases. MRV image fusion is feasible and may improve success, safety, and the surgeon's confidence during CVO recanalization. Similar to arterial interventions, three-dimensional MRV imaging and image fusion techniques could foster innovative solutions for such complex venous interventions and have the potential to affect a great number of patients. Copyright © 2016 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

Image Guidance Technologies for Interventional Pain Procedures: Ultrasound, Fluoroscopy, and CT.

PubMed

Wang, Dajie

2018-01-26

Chronic pain is a common medical condition. Patients who suffer uncontrolled chronic pain may require interventions including spinal injections and various nerve blocks. Interventional procedures have evolved and improved over time since epidural injection was first introduced for low back pain and sciatica in 1901. One of the major contributors in the improvement of these interventions is the advancement of imaging guidance technologies. The utilization of image guidance has dramatically improved the accuracy and safety of these interventions. The first image guidance technology adopted by pain specialists was fluoroscopy. This was followed by CT and ultrasound. Fluoroscopy can be used to visualize bony structures of the spine. It is still the most commonly used guidance technology in spinal injections. In the recent years, ultrasound guidance has been increasingly adopted by interventionists to perform various injections. Because its ability to visualize soft tissue, vessels, and nerves, this guidance technology appears to be a better option than fluoroscopy for interventions including SGB and celiac plexus blocks, when visualization of the vessels may prevent intravascular injection. The current evidence indicates the efficacies of these interventions are similar between ultrasound guidance and fluoroscopy guidance for SGB and celiac plexus blocks. For facet injections and interlaminar epidural steroid injections, it is important to visualize bony structures in order to perform these procedures accurately and safely. It is worth noting that facet joint injections can be done under ultrasound guidance with equivalent efficacy to fluoroscopic guidance. However, obese patients may present challenge for ultrasound guidance due to its poor visualization of deep anatomical structures. Regarding transforaminal epidural steroid injections, there are limited evidence to support that ultrasound guidance technology has equivalent efficacy and less complications comparing to fluoroscopy. However, further studies are required to prove the efficacy of ultrasound-guided transforaminal epidural injections. SI joint is unique due to its multiplanar orientation, irregular joint gap, partial ankylosis, and thick dorsal and interosseous ligament. Therefore, it can be difficult to access the joint space with fluoroscopic guidance and ultrasound guidance. CT scan, with its cross-sectional images, can identify posterior joint gap, is most likely the best guidance technology for this intervention. Intercostal nerves lie in the subcostal grove close to the plural space. Significant risk of pneumothorax is associated with intercostal blocks. Ultrasound can provide visualization of ribs and pleura. Therefore, it may improve the accuracy of the injection and reduce the risk of pneumothorax. At present time, most pain specialists are familiar with fluoroscopic guidance techniques, and fluoroscopic machines are readily available in the pain clinics. In the contrast, CT guidance can only be performed in specially equipped facilities. Ultrasound machine is generally portable and inexpensive in comparison to CT scanner and fluoroscopic machine. As pain specialists continue to improve their patient care, ultrasound and CT guidance will undoubtedly be incorporated more into the pain management practice. This review is based on a paucity of clinical evidence to compare these guidance technologies; clearly, more clinical studies is needed to further elucidate the pro and cons of each guidance method for various pain management interventions.

Obstructed bi-leaflet prosthetic mitral valve imaging with real-time three-dimensional transesophageal echocardiography.

PubMed

Shimbo, Mai; Watanabe, Hiroyuki; Kimura, Shunsuke; Terada, Mai; Iino, Takako; Iino, Kenji; Ito, Hiroshi

2015-01-01

Real-time three-dimensional transesophageal echocardiography (RT3D-TEE) can provide unique visualization and better understanding of the relationship among cardiac structures. Here, we report the case of an 85-year-old woman with an obstructed mitral prosthetic valve diagnosed promptly by RT3D-TEE, which clearly showed a leaflet stuck in the closed position. The opening and closing angles of the valve leaflets measured by RT3D-TEE were compatible with those measured by fluoroscopy. Moreover, RT3D-TEE revealed, in the ring of the prosthetic valve, thrombi that were not visible on fluoroscopy. RT3D-TEE might be a valuable diagnostic technique for prosthetic mitral valve thrombosis. © 2014 Wiley Periodicals, Inc.

"Turn laterally to the left!". The need for uniform C-arm communication terminology during orthopaedic trauma surgery.

PubMed

De Muinck Keizer, R-J; Klei, D S; Van Koperen, P J; Van Dijk, C N; Goslings, J C

2017-03-01

To avoid disturbed teamwork, unnecessary radiation exposure, and procedural delays, we designed and tested a uniform communication language for use in fluoroscopy-assisted surgical procedures. Input of surgeons and radiographers was used to create a set of commands. The potential benefit of this terminology was explored in an experimental setting. There was a tremendous diversity in the currently used terminology. Use of the newly designed terminology showed a reduction of procedural time and amount of images needed. Our first standardized Dutch language terminology can reduce total fluoroscopy time, number of images acquired, and potentially radiation exposure. For Dutch speaking colleagues, the developed terminology is freely available for use in their OR.

Tuberculosis Fluoroscopy

Cancer.gov

Follow-up though Dec 31, 2002 has been completed for a study of site-specific cancer mortality among tuberculosis patients treated with artificial lung collapse therapy in Massachusetts tuberculosis sanatoria (1930-1950).

42 CFR 411.351 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-10-01

... professional and technical components of any diagnostic test or procedure using x-rays, ultrasound...-ray, fluoroscopy, or ultrasound procedures that require the insertion of a needle, catheter, tube, or...

42 CFR 411.351 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-10-01

... professional and technical components of any diagnostic test or procedure using x-rays, ultrasound...-ray, fluoroscopy, or ultrasound procedures that require the insertion of a needle, catheter, tube, or...

42 CFR 411.351 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-10-01

... professional and technical components of any diagnostic test or procedure using x-rays, ultrasound...-ray, fluoroscopy, or ultrasound procedures that require the insertion of a needle, catheter, tube, or...

A prototype percutaneous transhepatic cholangiography training simulator with real-time breathing motion.

PubMed

Villard, P F; Vidal, F P; Hunt, C; Bello, F; John, N W; Johnson, S; Gould, D A

2009-11-01

We present here a simulator for interventional radiology focusing on percutaneous transhepatic cholangiography (PTC). This procedure consists of inserting a needle into the biliary tree using fluoroscopy for guidance. The requirements of the simulator have been driven by a task analysis. The three main components have been identified: the respiration, the real-time X-ray display (fluoroscopy) and the haptic rendering (sense of touch). The framework for modelling the respiratory motion is based on kinematics laws and on the Chainmail algorithm. The fluoroscopic simulation is performed on the graphic card and makes use of the Beer-Lambert law to compute the X-ray attenuation. Finally, the haptic rendering is integrated to the virtual environment and takes into account the soft-tissue reaction force feedback and maintenance of the initial direction of the needle during the insertion. Five training scenarios have been created using patient-specific data. Each of these provides the user with variable breathing behaviour, fluoroscopic display tuneable to any device parameters and needle force feedback. A detailed task analysis has been used to design and build the PTC simulator described in this paper. The simulator includes real-time respiratory motion with two independent parameters (rib kinematics and diaphragm action), on-line fluoroscopy implemented on the Graphics Processing Unit and haptic feedback to feel the soft-tissue behaviour of the organs during the needle insertion.

A motion-compensated image filter for low-dose fluoroscopy in a real-time tumor-tracking radiotherapy system

PubMed Central

Miyamoto, Naoki; Ishikawa, Masayori; Sutherland, Kenneth; Suzuki, Ryusuke; Matsuura, Taeko; Toramatsu, Chie; Takao, Seishin; Nihongi, Hideaki; Shimizu, Shinichi; Umegaki, Kikuo; Shirato, Hiroki

2015-01-01

In the real-time tumor-tracking radiotherapy system, a surrogate fiducial marker inserted in or near the tumor is detected by fluoroscopy to realize respiratory-gated radiotherapy. The imaging dose caused by fluoroscopy should be minimized. In this work, an image processing technique is proposed for tracing a moving marker in low-dose imaging. The proposed tracking technique is a combination of a motion-compensated recursive filter and template pattern matching. The proposed image filter can reduce motion artifacts resulting from the recursive process based on the determination of the region of interest for the next frame according to the current marker position in the fluoroscopic images. The effectiveness of the proposed technique and the expected clinical benefit were examined by phantom experimental studies with actual tumor trajectories generated from clinical patient data. It was demonstrated that the marker motion could be traced in low-dose imaging by applying the proposed algorithm with acceptable registration error and high pattern recognition score in all trajectories, although some trajectories were not able to be tracked with the conventional spatial filters or without image filters. The positional accuracy is expected to be kept within ±2 mm. The total computation time required to determine the marker position is a few milliseconds. The proposed image processing technique is applicable for imaging dose reduction. PMID:25129556

The effect of bench model fidelity on fluoroscopy-guided transforaminal epidural injection training: a randomized control study.

PubMed

Gonzalez-Cota, Alan; Chiravuri, Srinivas; Stansfield, R Brent; Brummett, Chad M; Hamstra, Stanley J

2013-01-01

The purpose of this study was to determine whether high-fidelity simulators provide greater benefit than low-fidelity models in training fluoroscopy-guided transforaminal epidural injection. This educational study was a single-center, prospective, randomized 3-arm pretest-posttest design with a control arm. Eighteen anesthesia and physical medicine and rehabilitation residents were instructed how to perform a fluoroscopy-guided transforaminal epidural injection and assessed by experts on a reusable injectable phantom cadaver. The high- and low-fidelity groups received 30 minutes of supervised hands-on practice according to group assignment, and the control group received 30 minutes of didactic instruction from an expert. We found no differences at posttest between the high- and low-fidelity groups on global ratings of performance (P = 0.17) or checklist scores (P = 0.81). Participants who received either form of hands-on training significantly outperformed the control group on both the global rating of performance (control vs low-fidelity, P = 0.0048; control vs high-fidelity, P = 0.0047) and the checklist (control vs low-fidelity, P = 0.0047; control vs high-fidelity, P = 0.0047). Training an epidural procedure using a low-fidelity model may be equally effective as training on a high-fidelity model. These results are consistent with previous research on a variety of interventional procedures and further demonstrate the potential impact of simple, low-fidelity training models.

Transbronchial cryobiopsy in interstitial lung disease: experience in 106 cases – how to do it

PubMed Central

Bango-Álvarez, Antonio; Torres-Rivas, Hector; Fernández-Fernández, Luis; Prieto, Amador; Sánchez, Inmaculada; Gil, Maria; Pando-Sandoval, Ana

2017-01-01

Transbronchial biopsy using forceps (TBB) is the first diagnostic technique performed on patients with interstitial lung disease (ILD). However, the small size of the samples and the presence of artefacts in the tissue obtained make the yield variable. Our objectives were 1) to attempt to reproduce transbronchial cryobiopsy under the same conditions with which we performed conventional TBB, that is, in the bronchoscopy unit without intubating the patient and without fluoroscopy or general anaesthesia; 2) to describe the method used for its execution; and 3) to analyse the diagnostic yield and its complications. We carried out a prospective study that included 106 patients with clinical and radiological features suggestive of ILD who underwent cryo-transbronchial lung biopsy (cryo-TBB) under moderate sedation without endotracheal intubation, general anaesthesia or use of fluoroscopy. We performed the procedure using two flexible bronchoscopes connected to two video processors, which we alternated until obtaining the number of desired samples. A definitive diagnosis was obtained in 91 patients (86%). As for complications, there were five pneumothoraces (4.7%) and in no case was there severe haemorrhage or exacerbation of the underlying interstitial disease. Cryo-TBB following our method is a minimally invasive, rapid, safe and economic technique that can be performed in a bronchoscopy suite under moderate sedation without the need for intubating the patient or using fluoroscopy and without requiring general anaesthesia. PMID:28344982

Are there any advantages in using a distal aiming device for tibial nailing? Comparing the Centro Nailing System with the Unreamed Tibia Nail.

PubMed

Veen, Egbert J D; Ettema, Harmen B; Zuurmond, Rutger G; Mostert, Adriaan K

2011-10-01

The distal locking of an intramedullary tibial nail can be challenging and time consuming when performed freehand. This study was conducted to evaluate if a distal aiming device would reduce surgical time. A case-controlled study was performed between 2007 and 2009 with 30 patients receiving a reamed tibial nail (Centronail) with the use of a distal aiming device and 30 patients who were treated with an Unreamed Tibia Nail (UTN), with freehand distal locking, in the same period. The primary outcome in this study was operative time. Secondary outcomes were the need for fluoroscopy, time to consolidation and complications. Operation time was longer in the Centronail group compared with the UTN group (126 min vs. 96 min, p=0.000). Use of fluoroscopy for distal locking was needed in half of the cases (n=16) using a distal aiming device. No differences were found regarding time to consolidation, time to removal of the nail and complications. The use of an aiming device for distal locking of a tibia nail lengthens operation time rather than reducing it. Fluoroscopy was still needed in about half of the cases. No difference was seen in clinical outcomes. The use of a distal aiming device to lock a tibial nail appears to have no benefit. Copyright © 2011 Elsevier Ltd. All rights reserved.

PubMed

Madeira, João; Parreira, Leonor; Amador, Pedro; Soares, Luís

2013-10-14

Riata and Riata ST silicone defibrillation leads are prone to externalization of conductors due to inside-out abrasion in the high-voltage system, causing structural damage which may be accompanied by electrical failure. These situations are easily detected by fluoroscopy or radiology and by inspection of intracardiac electrograms and/or measurement of impedance. However, older pulse generators do not automatically perform all the measurements needed to assess the integrity of the high-voltage electrical system, nor do they have patient notifier alerts in case of dysfunction. The authors describe the case of a patient in whom structural damage was detected on fluoroscopy during pulse generator replacement. They discuss the best strategy in these patients, considering current knowledge of this dysfunction. Copyright © 2012 Sociedade Portuguesa de Cardiologia. Published by Elsevier España. All rights reserved.

Modified fluoroscopy-guided sacroiliac joint injection: a technical report.

PubMed

Liliang, Po-Chou; Liang, Cheng-Loong; Lu, Kang; Weng, Hui-Ching; Syu, Fei-Kai

2014-09-01

Sacroiliac joint (SIJ) injection can occasionally be challenging. We describe our experience in using conventional technique, and we developed an adjustment to overcome difficulties incurred. Conventional technique required superimposition of the posterior and anterior SIJ lines. If this technique failed to provide entry into the joint, fluoroscopy was slightly adjusted to obtain an oblique view. Of 50 SIJ injections, 29 (58%; 44-72%) were successfully performed using conventional technique. In another 21 procedures, 18 (85.7%; 64-99%) were subsequently completed using oblique view technique. The medial joint line, viewed from this angle, corresponded to the posterior joint line in 17 cases. The lateral joint line corresponded to the posterior joint line in one case. Oblique view technique can improve the success rate of SIJ injection. Wiley Periodicals, Inc.

Iatrogenic deep musculocutaneous radiation injury following percutaneous coronary intervention.

PubMed

Monaco, JoAn L; Bowen, Kanika; Tadros, Peter N; Witt, Peter D

2003-08-01

Radiation-induced skin injury has been reported for multiple fluoroscopic procedures. Previous studies have indicated that prolonged fluoroscopic exposure during even a single percutaneous coronary intervention (PCI) may lead to cutaneous radiation injury. We document a novel case of deep muscle damage requiring wide local debridement and muscle flap reconstruction in a 59-year-old man with a large radiation-induced wound to the lower thoracic region following 1 prolonged PCI procedure. The deep muscular iatrogenic injury described in this report may be the source of significant morbidity. Recommendations to reduce radiation-induced damage include careful examination of the skin site before each procedure, minimized fluoroscopy time, utilization of pulse fluoroscopy, employment of radiation filters, and collimator s and rotation of the location of the image intensifier.

Technical advances of interventional fluoroscopy and flat panel image receptor.

PubMed

Lin, Pei-Jan Paul

2008-11-01

In the past decade, various radiation reducing devices and control circuits have been implemented on fluoroscopic imaging equipment. Because of the potential for lengthy fluoroscopic procedures in interventional cardiovascular angiography, these devices and control circuits have been developed for the cardiac catheterization laboratories and interventional angiography suites. Additionally, fluoroscopic systems equipped with image intensifiers have benefited from technological advances in x-ray tube, x-ray generator, and spectral shaping filter technologies. The high heat capacity x-ray tube, the medium frequency inverter generator with high performance switching capability, and the patient dose reduction spectral shaping filter had already been implemented on the image intensified fluoroscopy systems. These three underlying technologies together with the automatic dose rate and image quality (ADRIQ) control logic allow patients undergoing cardiovascular angiography procedures to benefit from "lower patient dose" with "high image quality." While photoconductor (or phosphor plate) x-ray detectors and signal capture thin film transistor (TFT) and charge coupled device (CCD) arrays are analog in nature, the advent of the flat panel image receptor allowed for fluoroscopy procedures to become more streamlined. With the analog-to-digital converter built into the data lines, the flat panel image receptor appears to become a digital device. While the transition from image intensified fluoroscopy systems to flat panel image receptor fluoroscopy systems is part of the on-going "digitization of imaging," the value of a flat panel image receptor may have to be evaluated with respect to patient dose, image quality, and clinical application capabilities. The advantage of flat panel image receptors has yet to be fully explored. For instance, the flat panel image receptor has its disadvantages as compared to the image intensifiers; the cost of the equipment is probably the most obvious. On the other hand, due to its wide dynamic range and linearity, lowering of patient dose beyond current practice could be achieved through the calibration process of the flat panel input dose rate being set to, for example, one half or less of current values. In this article various radiation saving devices and control circuits are briefly described. This includes various types of fluoroscopic systems designed to strive for reduction of patient exposure with the application of spectral shaping filters. The main thrust is to understand the ADRIQ control logic, through equipment testing, as it relates to clinical applications, and to show how this ADRIQ control logic "ties" those three technological advancements together to provide low radiation dose to the patient with high quality fluoroscopic images. Finally, rotational angiography with computed tomography (CT) and three dimensional (3-D) images utilizing flat panel technology will be reviewed as they pertain to diagnostic imaging in cardiovascular disease.

Hip joint injection

MedlinePlus

... medicine into the joint. The provider uses a real-time x-ray (fluoroscopy) to see where to place ... Wakefield RJ. Arthrocentesis and injection of joints and soft tissue. In: Firestein GS, Budd RC, Gabriel SE, ...

Fistulogram/Sinogram

MedlinePlus

... Fistulogram/Sinogram A fistulogram uses a form of real-time x-ray called fluoroscopy and a barium-based ... best treatment plan for you. Fistulograms/sinograms provide real-time images that may be evaluated immediately. No radiation ...

Radiation Exposure During Uterine Artery Embolization: Effective Measures to Minimize Dose to the Patient

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scheurig-Muenkler, Christian, E-mail: christian.scheurig@charite.de; Powerski, Maciej J., E-mail: maciej.powerski@med.ovgu.de; Mueller, Johann-Christoph, E-mail: johann-christoph.mueller@charite.de

PurposeEvaluation of patient radiation exposure during uterine artery embolization (UAE) and literature review to identify techniques minimizing required dose.MethodsA total of 224 of all included 286 (78 %) women underwent UAE according to a standard UAE-protocol (bilateral UAE from unilateral approach using a Rösch inferior mesenteric and a microcatheter, no aortography, no ovarian artery catheterization or embolization) and were analyzed for radiation exposure. Treatment was performed on three different generations of angiography systems: (I) new generation flat-panel detector (N = 108/151); (II) classical image amplifier and pulsed fluoroscopy (N = 79/98); (III) classical image amplifier and continuous fluoroscopy (N = 37/37). Fluoroscopy time (FT) and dose-area productmore » (DAP) were documented. Whenever possible, the following dose-saving measures were applied: optimized source-object, source-image, and object-image distances, pulsed fluoroscopy, angiographic runs in posterior-anterior direction with 0.5 frames per second, no magnification, tight collimation, no additional aortography.ResultsIn a standard bilateral UAE, the use of the new generation flat-panel detector in group I led to a significantly lower DAP of 3,156 cGy × cm{sup 2} (544–45,980) compared with 4,000 cGy × cm{sup 2} (1,400–13,000) in group II (P = 0.033). Both doses were significantly lower than those of group III with 8,547 cGy × cm{sup 2} (3,324–35,729; P < 0.001). Other reasons for dose escalation were longer FT due to difficult anatomy or a large leiomyoma load, additional angiographic runs, supplementary ovarian artery embolization, and obesity.ConclusionsThe use of modern angiographic units with flat panel detectors and strict application of methods of radiation reduction lead to a significantly lower radiation exposure. Target DAP for UAE should be kept below 5,000 cGy × cm{sup 2}.« less

Deformable 3D-2D registration for CT and its application to low dose tomographic fluoroscopy

NASA Astrophysics Data System (ADS)

Flach, Barbara; Brehm, Marcus; Sawall, Stefan; Kachelrieß, Marc

2014-12-01

Many applications in medical imaging include image registration for matching of images from the same or different modalities. In the case of full data sampling, the respective reconstructed images are usually of such a good image quality that standard deformable volume-to-volume (3D-3D) registration approaches can be applied. But research in temporal-correlated image reconstruction and dose reductions increases the number of cases where rawdata are available from only few projection angles. Here, deteriorated image quality leads to non-acceptable deformable volume-to-volume registration results. Therefore a registration approach is required that is robust against a decreasing number of projections defining the target position. We propose a deformable volume-to-rawdata (3D-2D) registration method that aims at finding a displacement vector field maximizing the alignment of a CT volume and the acquired rawdata based on the sum of squared differences in rawdata domain. The registration is constrained by a regularization term in accordance with a fluid-based diffusion. Both cost function components, the rawdata fidelity and the regularization term, are optimized in an alternating manner. The matching criterion is optimized by a conjugate gradient descent for nonlinear functions, while the regularization is realized by convolution of the vector fields with Gaussian kernels. We validate the proposed method and compare it to the demons algorithm, a well-known 3D-3D registration method. The comparison is done for a range of 4-60 target projections using datasets from low dose tomographic fluoroscopy as an application example. The results show a high correlation to the ground truth target position without introducing artifacts even in the case of very few projections. In particular the matching in the rawdata domain is improved compared to the 3D-3D registration for the investigated range. The proposed volume-to-rawdata registration increases the robustness regarding sparse rawdata and provides more stable results than volume-to-volume approaches. By applying the proposed registration approach to low dose tomographic fluoroscopy it is possible to improve the temporal resolution and thus to increase the robustness of low dose tomographic fluoroscopy.

SU-E-J-59: Feasibility of Markerless Tumor Tracking by Sequential Dual-Energy Fluoroscopy On a Clinical Tumor Tracking System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dhont, J; Poels, K; Verellen, D

2015-06-15

Purpose: To evaluate the feasibility of markerless tumor tracking through the implementation of a novel dual-energy imaging approach into the clinical dynamic tracking (DT) workflow of the Vero SBRT system. Methods: Two sequential 20 s (11 Hz) fluoroscopy sequences were acquired at the start of one fraction for 7 patients treated for primary and metastatic lung cancer with DT on the Vero system. Sequences were acquired using 2 on-board kV imaging systems located at ±45° from the MV beam axis, at respectively 60 kVp (3.2 mAs) and 120 kVp (2.0 mAs). Offline, a normalized cross-correlation algorithm was applied to matchmore » the high (HE) and low energy (LE) images. Per breathing phase (inhale, exhale, maximum inhale and maximum exhale), the 5 best-matching HE and LE couples were extracted for DE subtraction. A contrast analysis according to gross tumor volume was conducted based on contrast-to-noise ratio (CNR). Improved tumor visibility was quantified using an improvement ratio. Results: Using the implanted fiducial as a benchmark, HE-LE sequence matching was effective for 13 out of 14 imaging angles. Overlying bony anatomy was removed on all DE images. With the exception of two imaging angles, the DE images showed no significantly improved tumor visibility compared to HE images, with an improvement ratio averaged over all patients of 1.46 ± 1.64. Qualitatively, it was observed that for those imaging angles that showed no significantly improved CNR, the tumor tissue could not be reliably visualized on neither HE nor DE images due to a total or partial overlap with other soft tissue. Conclusion: Dual-energy subtraction imaging by sequential orthogonal fluoroscopy was shown feasible by implementing an additional LE fluoroscopy sequence. However, for most imaging angles, DE images did not provide improved tumor visibility over single-energy images. Optimizing imaging angles is likely to improve tumor visibility and the efficacy of dual-energy imaging. This work was in part sponsored by corporate funding from BrainLAB AG.(BrainLAB AG, Feldkirchen, Germany)« less

Fluoroscopy-Guided Pull-Through Gastrostomy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pitton, M. B., E-mail: pitton@radiologie.klinik.uni-mainz.de; Herber, S.; Dueber, C.

2008-01-15

The purpose of this study was to simplify a fluoroscopy guided gastrostomy technique using pull-type tubes which are traditionally introduced with gastroscopic assistance. The stomach was transorally probed with a 5-Fr catheter and a guidewire. A second access was performed percutaneously through the anterior abdominal and gastric wall using an 8-Fr sheath and an 8-Fr guiding catheter. A duplicated guidewire was introduced through the guiding catheter in order to result in a great custom-made loop within the stomach. The transoral guidewire was captured and tightened with this loop and the guiding catheter, and both were subsequently pulled by the transoralmore » guidewire until the tip of the guiding catheter exited the mouth. A thread was fed through the guiding catheter for fixation of the pull-type gastrostomy tube. Finally, the fixed tube was pulled through the esophagus into the stomach and through the abdominal wall until the anterior gastric wall fixed the retention plate of the tube. Thirty-seven patients (28 male, 9 female; age, 65.1 {+-} 14.4 years) with miscellaneous indications for percutaneous gastrostomies were supplied with pull-type gastrostomy catheters in a fluoroscopy technique without endoscopic assistance. Twenty-five of the 37 patients (67.6%) had undergone unsuccessful preceding gastroscopically guided PEG attempts because of tumor stenosis (n = 12) or impossible transillumination of the abdominal wall (n = 13). All procedures were technically successful, without major complications. Particularly, all patients with frustrating gastroscopic attempts were successfully provided with pull-type gastrostomy tubes. Five minor complications occurred: one tube loss during the passage of the hypopoharynx because of a torn thread, one transient small leakage alongside the tube (both successfully treated), and three cases of transient moderate local pain without leakage (symptomatic treatment). We conclude that this fluoroscopy-guided pull-through gastrostomy technique is easy and safe to perform and may be suggested as a standard procedure for radiological gastrostomies. It combines the ease of the radiological approach with the advantages of the pull-type tube devices, particularly the benefits of the typical retention plates.« less

75 FR 4088 - Medicare Program; Approval of Independent Accrediting Organizations To Participate in the...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-26

...) (excluding x-ray, ultrasound, and fluoroscopy), as specified by the Secretary in consultation with physician... ``imaging and computer-assisted imaging services, including x-ray, ultrasound (including echocardiography...

Percutaneous Facet Screw Fixation in the Treatment of Symptomatic Recurrent Lumbar Facet Joint Cyst: A New Technique

DOE Office of Scientific and Technical Information (OSTI.GOV)

Amoretti, Nicolas, E-mail: amorettinicolas@yahoo.fr; Gallo, Giacomo, E-mail: giacomo.gallo83@gmail.com; Bertrand, Anne-Sophie, E-mail: asbertrand3@hotmail.com

We present a case of percutaneous treatment of symptomatic recurrent lumbar facet joint cyst resistant to all medical treatments including facet joint steroid injection. Percutaneous transfacet fixation was then performed at L4–L5 level with a cannulated screw using CT and fluoroscopy guidance. The procedure time was 30 min. Using the visual analog scale (VAS), pain decreased from 9.5, preoperatively, to 0 after the procedure. At 6-month follow-up, an asymptomatic cystic recurrence was observed, which further reduced at the 1-year follow-up. Pain remained stable (VAS at 0) during all follow-ups. CT- and fluoroscopy-guided percutaneous cyst rupture associated with facet screw fixation couldmore » be an alternative to surgery in patients suffering from a symptomatic recurrent lumbar facet joint cyst.« less

A novel drill design for photoacoustic guided surgeries

NASA Astrophysics Data System (ADS)

Shubert, Joshua; Lediju Bell, Muyinatu A.

2018-02-01

Fluoroscopy is currently the standard approach for image guidance of surgical drilling procedures. In addition to the harmful radiation dose to the patient and surgeon, fluoroscopy fails to visualize critical structures such as blood vessels and nerves within the drill path. Photoacoustic imaging is a well-suited imaging method to visualize these structures and it does not require harmful ionizing radiation. However, there is currently no clinical system available to deliver light to occluded drill bit tips. To address this challenge, a prototype drill was designed, built, and tested using an internal light delivery system that allows laser energy to be transferred from a stationary laser source to the tip of a spinning drill bit. Photoacoustic images were successfully obtained with the drill bit submerged in water and with the drill tip inserted into a thoracic vertebra from a human cadaver.

Analysis of the Flexion Gap on In Vivo Knee Kinematics Using Fluoroscopy.

PubMed

Nakamura, Shinichiro; Ito, Hiromu; Yoshitomi, Hiroyuki; Kuriyama, Shinichi; Komistek, Richard D; Matsuda, Shuichi

2015-07-01

There is a paucity of information on the relationships between postoperative knee laxity and in vivo knee kinematics. The correlations were analyzed in 22 knees with axial radiographs and fluoroscopy based 3D model fitting approach after a tri-condylar total knee arthroplasty. During deep knee bend activities, the medial flexion gap had significant correlations with the medial contact point (r=0.529, P=0.011) and axial rotation at full extension. During kneeling activities, a greater medial flexion gap caused larger anterior translation at complete contact (r=0.568, P=0.011). Meanwhile, the lateral flexion gap had less effect. In conclusion, laxity of the medial collateral ligament should be avoided because the magnitude of medial flexion stability was crucial for postoperative knee kinematics. Copyright © 2015 Elsevier Inc. All rights reserved.

Reducing ionizing radiation doses during cardiac interventions in pregnant women.

PubMed

Orchard, Elizabeth; Dix, Sarah; Wilson, Neil; Mackillop, Lucy; Ormerod, Oliver

2012-09-01

There is concern over ionizing radiation exposure in women who are pregnant or of child-bearing age. Due to the increasing prevalence of congenital and acquired heart disease, the number of women who require cardiac interventions during pregnancy has increased. We have developed protocols for cardiac interventions in pregnant women and women of child-bearing age, aimed at substantially reducing both fluoroscopy duration and radiation doses. Over five years, we performed cardiac interventions on 15 pregnant women, nine postpartum women and four as part of prepregnancy assessment. Fluoroscopy times were minimized by simultaneous use of intracardiac echocardiography, and by using very low frame rates (2/second) during fluoroscopy. The procedures most commonly undertaken were closure of atrial septal defect (ASD) or patent foramen ovale (PFO) in 16 women, coronary angiograms in seven, right and left heart catheters in three and two stent placements. The mean screening time for all patients was 2.38 minutes (range 0.48-13.7), the median radiation dose was 66 (8.9-1501) Gy/cm(2). The median radiation dose to uterus was 1.92 (0.59-5.47) μGy, and the patient estimated dose was 0.24 (0.095-0.80) mSv. Ionizing radiation can be used safely in the management of severe cardiac structural disease in pregnancy, with very low ionizing radiation dose to the mother and extremely low exposure to the fetus. With experience, ionizing radiation doses at our institution have been reduced.

A comparison among four tract dilation methods of percutaneous nephrolithotomy: a systematic review and meta-analysis.

PubMed

Dehong, Cao; Liangren, Liu; Huawei, Liu; Qiang, Wei

2013-11-01

The purpose of this study was to evaluate the efficacy and safety of the Amplatz dilation (AD), metal telescopic dilation (MTD), balloon dilation (BD), and one-shot dilation (OSD) methods for tract dilation during percutaneous nephrolithotomy (PCNL). Relevant eligible studies were identified using three electronic databases (Medline, EMBASE, and Cochrane CENTRAL). Database acquisition and quality evaluation were independently performed by two reviewers. Efficacy (stone-free rate, surgical duration, and tract dilatation fluoroscopy time) and safety (transfusion rate and hemoglobin decrease) were evaluated using Review Manager 5.2. Four randomized controlled trials and eight clinical controlled trials involving 6,820 patients met the inclusion criteria. The pooled result from a meta-analysis showed statistically significant differences in tract dilatation fluoroscopy time and hemoglobin decrease between the OSD and MTD groups, which showed comparable stone-free and transfusion rates. Significant differences in transfusion rate were found between the BD and MTD groups. Among patients without previous open renal surgery, those who underwent BD exhibited a lower blood transfusion rate and a shorter surgical duration compared with those who underwent AD. The OSD technique is safer and more efficient than the MTD technique for tract dilation during PCNL, particularly in patients with previous open renal surgery, resulting in a shorter tract dilatation fluoroscopy time and a lesser decrease in hemoglobin. The efficacy and safety of BD are better than AD in patients without previous open renal surgery. The OSD technique should be considered for most patients who undergo PCNL therapy.

The hounsfield unit value calculated with the aid of non-contrast computed tomography and its effect on the outcome of percutaneous nephrolithotomy.

PubMed

Gok, Alper; Polat, Haci; Cift, Ali; Yucel, Mehmet Ozgur; Gok, Bahri; Sirik, Mehmet; Benlioglu, Can; Kalyenci, Bedreddin

2015-06-01

To evaluate the effect of the Hounsfield unit (HU) value, calculated with the aid of non-contrast computed tomography, on the outcome of percutaneous nephrolithotomy (PCNL). Data for 83 patients evaluated in our clinic between November 2011 and February 2014 that had similar stone sizes, localizations, and radio opacities were retrospectively reviewed. The patients were grouped according to their HU value, in a low HU group (HU ≤ 1000) or a high HU group (HU > 1000). The two groups were compared based on their PCNL success rates, complications, duration of surgery, duration of fluoroscopy, and decrease in the hematocrit. There were no significant differences in terms of mean age, female-male ratio, or mean body mass index between the two groups (p > 0.05). The stone size and stone surface area did not differ significantly between the groups (p = 0.820 and p = 0.394, respectively). The unsuccessful PCNL rate and the prevalence of complications did not differ significantly between the two groups (p > 0.05). The duration of surgery, duration of fluoroscopy, and decrease in the hematocrit were significantly greater in the high HU group compared to the low HU group (p < 0.001). Calculating the HU value using this imaging method may predict cases with longer surgery durations, longer fluoroscopy durations, and greater decreases in hematocrite levels, but this value is not related to the success rate of PCNL.

Feasibility and safety of transfemoral intra-arterial chemotherapy for head and neck cancer using a 3-French catheter system: comparison with a 4-French catheter system.

PubMed

Watanabe, Shigeru; Yamamoto, Akira; Torigoe, Teruyuki; Kanki, Akihiko; Tamada, Tsutomu; Ito, Katsuyoshi

2016-02-01

To assess the technical feasibility of transfemoral intra-arterial chemotherapy for head and neck cancer using a 3-French catheter system (3-Fr). Sixty-two patients with head and neck cancer who underwent transfemoral intra-arterial chemotherapy were included in this study. Thirty-three patients underwent treatment using a 3-Fr (group 3-Fr). Twenty-nine patients underwent treatment using a 4-French catheter system (group 4-Fr). The technical success rate, duration of the procedure with fluoroscopy, and rate of procedure-related complications were compared between group 3-Fr and group 4-Fr. In addition, in group 3-Fr, bleeding at the puncture site after 1.5 h of bed rest was evaluated. The technical success rate was 100% in both groups. The duration of the procedure with fluoroscopy didn't differ between group 3-Fr (mean 28.0 min) and group 4-Fr (mean 30.2 min) (p = 0.524). There was no procedure-related complication in either group. In group 3-Fr, no hemorrhagic complication was observed. A 3-French catheter system can be used to perform transfemoral intra-arterial chemotherapy for head and neck cancer and is technically feasible with approximately the same duration of the procedure with fluoroscopy. Furthermore, this method may shorten the bed rest time without hemorrhagic complication, and may reduce the risk of pulmonary embolism.

3D/2D image registration method for joint motion analysis using low-quality images from mini C-arm machines

NASA Astrophysics Data System (ADS)

Ghafurian, Soheil; Hacihaliloglu, Ilker; Metaxas, Dimitris N.; Tan, Virak; Li, Kang

2017-03-01

A 3D kinematic measurement of joint movement is crucial for orthopedic surgery assessment and diagnosis. This is usually obtained through a frame-by-frame registration of the 3D bone volume to a fluoroscopy video of the joint movement. The high cost of a high-quality fluoroscopy imaging system has hindered the access of many labs to this application. This is while the more affordable and low-dosage version, the mini C-arm, is not commonly used for this application due to low image quality. In this paper, we introduce a novel method for kinematic analysis of joint movement using the mini C-arm. In this method the bone of interest is recovered and isolated from the rest of the image using a non-rigid registration of an atlas to each frame. The 3D/2D registration is then performed using the weighted histogram of image gradients as an image feature. In our experiments, the registration error was 0.89 mm and 2.36° for human C2 vertebra. While the precision is still lacking behind a high quality fluoroscopy machine, it is a good starting point facilitating the use of mini C-arms for motion analysis making this application available to lower-budget environments. Moreover, the registration was highly resistant to the initial distance from the true registration, converging to the answer from anywhere within +/-90° of it.

Guidewire navigation in coronary artery stenoses using a novel magnetic navigation system: first clinical experience.

PubMed

Tsuchida, Keiichi; García-García, Héctor M; van der Giessen, Willem J; McFadden, Eugène P; van der Ent, Martin; Sianos, Georgios; Meulenbrug, Hans; Ong, Andrew T L; Serruys, Patrick W

2006-03-01

The objective of this study was to investigate the efficacy of guidewire navigation across coronary artery stenoses using magnetic navigation system (MNS) versus conventional navigation. The MNS is a novel option to facilitate access to target lesions, particularly in tortuous vessels. In an experimental study using a challenging vessel phantom, magnetic-navigated guidewire passage has been reported to reduce fluoroscopy and procedure time significantly. Both magnetic and manual guidewire navigation were attempted in 21 consecutive diseased coronary arteries. The study endpoint was defined as an intraluminal wire position distal to the stenosis. Procedural success was defined as successful guidewire passage without procedural events. Procedure time, amount of contrast, fluoroscopy time, and radiation dose/area product (DAP) were evaluated. There were no procedural events related to either guidewire. Although the lesions attempted had relatively simple and straightforward characteristics, significantly shorter procedure and fluoroscopy time were observed for manual guidewire navigation compared to MNS (median, 40 vs. 120 sec, P=0.001; 38 vs. 105 sec, P=0.001, respectively). Contrast amount and DAP were higher in MNS than in conventional method (median, 13 vs. 9 ml, P=0.018; 215 vs. 73 Gym2, P=0.002, respectively). The magnetic wire did not cross in two vessels. Guidewire navigation using MNS presented a novel, safe, and feasible approach to address coronary artery lesions. Clinical studies are needed to evaluate the potential benefit of the MNS in more complex coronary lesions and tortuous anatomy. Copyright (c) 2006 Wiley-Liss, Inc.

CT fluoroscopy-guided percutaneous drainage: comparison of the one step and the Seldinger techniques.

PubMed

Kajiwara, Kenji; Yamagami, Takuji; Ishikawa, Masaki; Yoshimatsu, Rika; Baba, Yasutaka; Nakamura, Yuko; Fukumoto, Wataru; Awai, Kazuo

2017-06-01

To evaluate the one step technique compared with the Seldinger technique in computed tomography (CT) fluoroscopy-guided percutaneous drainage of abdominal and pelvic abscess. Seventy-six consecutive patients (49 men, 27 women; mean age 63.5 years, range 19-87 years) with abdominal and pelvic abscess were included in this study. Drainages were performed with the one step (n = 46) and with the Seldinger (n = 48) technique between September 2012 and June 2014. The technical success and clinical success rates were 95.8% and 93.5%, respectively, for the one step group, and 97.8% and 95.7%, respectively, for the Seldinger group. The mean procedure time was significantly shorter with the one step than with the Seldinger method (15.0 ± 4.3 min, range 10-29 min vs. 21.0 ± 9.5 min, range 13-54 min, p < .01). The mean abscess size and depth were 73.4 ± 44.0 mm and 42.5 ± 19.3 mm, respectively, in the one step group, and 61.0 ± 22.8 mm and 35.0 ± 20.7 mm in the Seldinger group. The one step technique was easier and faster than the Seldinger technique. The effectiveness of both techniques was similar for the CT fluoroscopy-guided percutaneous drainage of abdominal and pelvic abscess.

Meta-Analysis of Zero or Near-Zero Fluoroscopy Use During Ablation of Cardiac Arrhythmias.

PubMed

Yang, Li; Sun, Ge; Chen, Xiaomei; Chen, Guangzhi; Yang, Shanshan; Guo, Ping; Wang, Yan; Wang, Dao Wen

2016-11-15

Data regarding the efficacy and safety of zero or near-zero fluoroscopic ablation of cardiac arrhythmias are limited. A literature search was conducted using PubMed and Embase for relevant studies through January 2016. Ten studies involving 2,261 patients were identified. Compared with conventional radiofrequency ablation method, zero or near-zero fluoroscopy ablation significantly showed reduced fluoroscopic time (standard mean difference [SMD] -1.62, 95% CI -2.20 to -1.05; p <0.00001), ablation time (SMD -0.16, 95% CI -0.29 to -0.04; p = 0.01), and radiation dose (SMD -1.94, 95% CI -3.37 to -0.51; p = 0.008). In contrast, procedure duration was not significantly different from that of conventional radiofrequency ablation (SMD -0.03, 95% CI -0.16 to 0.09; p = 0.58). There were no significant differences between both groups in immediate success rate (odds ratio [OR] 0.99, 95% CI 0.49 to 2.01; p = 0.99), long-term success rate (OR 1.13, 95% CI 0.42 to 3.02; p = 0.81), complication rates (OR 0.98, 95% CI 0.49 to 1.96; p = 0.95), and recurrence rates (OR 1.29, 95% CI 0.74 to 2.24; p = 0.37). In conclusion, radiation was significantly reduced in the zero or near-zero fluoroscopy ablation groups without compromising efficacy and safety. Copyright © 2016 Elsevier Inc. All rights reserved.

Determination of Gastrointestinal Transit Times in Barred Owls ( Strix varia ) by Contrast Fluoroscopy.

PubMed

Doss, Grayson A; Williams, Jackie M; Mans, Christoph

2017-06-01

Contrast imaging studies are routinely performed in avian patients when an underlying abnormality of the gastrointestinal (GI) tract is suspected. Fluoroscopy offers several advantages over traditional radiography and can be performed in conscious animals with minimal stress and restraint. Although birds of prey are commonly encountered as patients, little is known about GI transit times and contrast imaging studies in these species, especially owls. Owls are commonly encountered in zoological, educational, and wildlife settings. In this study, 12 adult barred owls ( Strix varia ) were gavage fed a 30% weight-by-volume barium suspension (25 mL/kg body weight). Fluoroscopic exposures were recorded at 5, 15, 30, 60, 120, 180, 240, and 300 minutes after administration. Overall GI transit time and transit times of various GI organs were recorded. Median (interquartile range [IQR]) overall GI transit time was 60 minutes (IQR: 19-60 minutes) and ranged from 5-120 minutes. Ventricular and small intestinal contrast filling was rapid. Ventricular emptying was complete by a median of 60 minutes (IQR: 30-120 minutes; range: 30-240 minutes), whereas small intestinal emptying was not complete in 9/12 birds by 300 minutes. Median small intestinal contraction rate was 15 per minute (IQR: 13-16 minutes; range: 10-19 minutes). Median overall GI transit time in barred owls is more rapid than mean transit times reported for psittacine birds and red-tailed hawks ( Buteo jamaicensis ). Fluoroscopy is a safe, suitable method for investigating GI motility and transit in this species.

Retrieval characteristics of the Bard Denali and Argon Option inferior vena cava filters.

PubMed

Dowell, Joshua D; Semaan, Dominic; Makary, Mina S; Ryu, John; Khayat, Mamdouh; Pan, Xueliang

2017-11-01

The purpose of this study was to compare the retrieval characteristics of the Option Elite (Argon Medical, Plano, Tex) and Denali (Bard, Tempe, Ariz) retrievable inferior vena cava filters (IVCFs), two filters that share a similar conical design. A single-center, retrospective study reviewed all Option and Denali IVCF removals during a 36-month period. Attempted retrievals were classified as advanced if the routine "snare and sheath" technique was initially unsuccessful despite multiple attempts or an alternative endovascular maneuver or access site was used. Patient and filter characteristics were documented. In our study, 63 Option and 45 Denali IVCFs were retrieved, with an average dwell time of 128.73 and 99.3 days, respectively. Significantly higher median fluoroscopy times were experienced in retrieving the Option filter compared with the Denali filter (12.18 vs 6.85 minutes; P = .046). Use of adjunctive techniques was also higher in comparing the Option filter with the Denali filter (19.0% vs 8.7%; P = .079). No significant difference was noted between these groups in regard to gender, age, or history of malignant disease. Option IVCF retrieval procedures required significantly longer retrieval fluoroscopy time compared with Denali IVCFs. Although procedure time was not analyzed in this study, as a surrogate, the increased fluoroscopy time may also have an impact on procedural direct costs and throughput. Copyright © 2017 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

Using biplanar fluoroscopy to guide radiopaque vascular injections: a new method for vascular imaging.

PubMed

O'Brien, Haley D; Williams, Susan H

2014-01-01

Studying vascular anatomy, especially in the context of relationships with hard tissues, is of great interest to biologists. Vascular studies have provided significant insight into physiology, function, phylogenetic relationships, and evolutionary patterns. Injection of resin or latex into the vascular system has been a standard technique for decades. There has been a recent surge in popularity of more modern methods, especially radiopaque latex vascular injection followed by CT scanning and digital "dissection." This technique best displays both blood vessels and bone, and allows injections to be performed on cadaveric specimens. Vascular injection is risky, however, because it is not a standardizable technique, as each specimen is variable with regard to injection pressure and timing. Moreover, it is not possible to view the perfusion of injection medium throughout the vascular system of interest. Both data and rare specimens can therefore be lost due to poor or excessive perfusion. Here, we use biplanar video fluoroscopy as a technique to guide craniovascular radiopaque latex injection. Cadaveric domestic pigs (Sus scrofa domestica) and white-tailed deer (Odocoileus virginianus) were injected with radiopaque latex under guidance of fluoroscopy. This method was found to enable adjustments, in real-time, to the rate, location, and pressure at which latex is injected in order to avoid data and specimen loss. In addition to visualizing the injection process, this technique can be used to determine flow patterns, and has facilitated the development of consistent markers for complete perfusion.

Towards active image-guidance: tracking of a fiducial in the thorax during respiration under X-ray fluoroscopy

NASA Astrophysics Data System (ADS)

Siddique, Sami; Jaffray, David

2007-03-01

A central purpose of image-guidance is to assist the interventionalist with feedback of geometric performance in the direction of therapy delivery. Tradeoffs exist between accuracy, precision and the constraints imposed by parameters used in the generation of images. A framework that uses geometric performance as feedback to control these parameters can balance such tradeoffs in order to maintain the requisite localization precision for a given clinical procedure. We refer to this principle as Active Image-Guidance (AIG). This framework requires estimates of the uncertainty in the estimated location of the object of interest. In this study, a simple fiducial marker detected under X-ray fluoroscopy is considered and it is shown that a relation exists between the applied imaging dose and the uncertainty in localization for a given observer. A robust estimator of the location of a fiducial in the thorax during respiration under X-ray fluoroscopy is demonstrated using a particle filter based approach that outputs estimates of the location and the associated spatial uncertainty. This approach gives an rmse of 1.3mm and the uncertainty estimates are found to be correlated with the error in the estimates. Furthermore, the particle filtering approach is employed to output location estimates and the associated uncertainty not only at instances of pulsed exposure but also between exposures. Such a system has applications in image-guided interventions (surgery, radiotherapy, interventional radiology) where there are latencies between the moment of imaging and the act of intervention.

Ultrasound guided transarterial coil placement in the internal and external carotid artery in horses.

PubMed

Muñoz, Juan; Iglesias, Manuel; Chao, Eduardo Lloret; Bussy, Christian

2015-04-01

To assess ultrasound guided transarterial coil placement (UGTACP) for occlusion of the internal carotid artery (ICA) and external carotid artery (ECA) in horses. Cadaveric and in vivo study. Cadaveric horses (n = 10), healthy horses (3), and 1 clinical case. Cadaveric and in vivo (healthy horses): UGTACP was performed in the caudal part of the ICA and ECA. Coil placement in the rostral part of the ICA was performed blindly and controlled by conventional radiography. No coils were placed in the rostral part of the ECA. UGTACP of the ICA was in a horse with guttural pouch mycosis of the left guttural pouch. Accurate ultrasound-guided catheterization of the ICA and ECA was performed in all specimens. Ultrasound-guided coil placement was successfully performed in all cases except 1. No complications occurred in the in vivo study. The clinical case fully recovered and returned to its intended use. Based on our study, UGTACP of the ICA and ECA caudal part is a feasible alternative to fluoroscopy. An advantage of this technique is the accuracy with which you can catheterize both ICA and ECA and the ability to identify unusual branching at the origin of the ICA. Regarding the rostral part of the ICA, angiographic catheter guidance in this region is probably more precise using fluoroscopy as it is performed blindly. In a clinical situation, combination of US and fluoroscopy guidance can result in reduction of radiation exposure time. © Copyright 2014 by The American College of Veterinary Surgeons.

77 FR 12848 - Medicare Program; Solicitation of Independent Accrediting Organizations To Participate in the...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-02

...)(4)(B) (excluding x-ray, ultrasound, and fluoroscopy), as specified by the Secretary in consultation... imaging services as ``imaging and computer-assisted imaging services, including x-ray, ultrasound...

Ultrasound-Guided Angioplasty of Dysfunctional Vascular Access for Haemodialysis. The Pros and Cons

DOE Office of Scientific and Technical Information (OSTI.GOV)

García-Medina, J., E-mail: josegmedina57@gmail.com; García-Alfonso, J. J., E-mail: juanjozarandieta@gmail.com

PurposeTo describe the benefits and the disadvantages of angioplasty in dialysis fistulas using only ultrasound guidance.Materials and MethodsThis is a prospective study in 132 failing or non-maturing arteriovenous accesses that underwent 189 ultrasound-guided balloon angioplasties. The technical success was defined as non-use of X-ray fluoroscopy during the procedure.Results127 procedures (67%) were successfully completed without fluoroscopy. Most failures were due to difficulty to traverse aneurismal segments, as well as anastomotic stenoses. Including initial failures, the primary patency rates at 6, 12 months and 2 years were 75 ± 3, 41 ± 3 and 14 ± 2%, respectively.ConclusionEndovascular repair of the dysfunctional vascular access for haemodialysis under ultrasound guidance ismore » feasible and safe in roughly two-thirds of cases.« less

MO-DE-201-03: This course presents a review of radiologic anatomy and physiology as it applies to projection radiography, fluoroscopy, CT, MRI, U/S, and nuclear medicine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fahey, F.

Fundamental knowledge of radiologic anatomy and physiology is critical for medical physicists. Many physicists are exposed to this topic only in graduate school, and knowledge is seldom formally evaluated or assessed after Part I of the ABR exam. Successful interactions with clinicians, including surgeons, radiologists, and oncologists requires that the medical physicist possess this knowledge. This course presents a review of radiologic anatomy and physiology as it applies to projection radiography, fluoroscopy, CT, MRI, U/S, and nuclear medicine. We will review structural anatomy, manipulation of tissue contrast, the marriage between anatomy and physiology, and explore how medical imaging exploits normalmore » and pathological processes in the body to generate contrast. Learning Objectives: Review radiologic anatomy. Examine techniques to manipulate tissue contrast in radiology. Integrate anatomy and physiology in molecular imaging.« less

Monorail Piccolino catheter: a new rapid exchange/ultralow profile coronary angioplasty system.

PubMed

Mooney, M R; Douglas, J S; Mooney, J F; Madison, J D; Brandenburg, R O; Fernald, R; Van Tassel, R A

1990-06-01

The Monorail Piccolino coronary angioplasty balloon catheter (MBC) was evaluated on 118 patients at two centers. Technical success was achieved in 110 patients (93%). Time for catheter exchange and total fluoroscopy time were significantly lower for the Monorail catheter than with standard equipment (exchange time 97 vs. 170 seconds P less than .05 and fluoroscopy time 17 vs. 88 seconds P less than .001). The advantages of rapid exchange and the ability of utilize 2 Monorail balloon catheters through one 9F guiding catheter for simultaneous inflations allowed for maximal flexibility in treating patients with bifurcation lesions. The double wire approach utilizing one Monorail balloon catheter with a 7F guiding catheter was also technically successful. The Monorail Piccolino balloon catheter has unique features that allow for greater ease of operator use, rapid catheter exchange, and optimal angiographic visualization. It is felt that this catheter design provides distinct advantages over standard angioplasty equipment.

Fluoroscopy-guided reduction and fibular nail fixation to manage unstable ankle fractures in patients with diabetes: a retrospective cohort study.

PubMed

Ashman, B D; Kong, C; Wing, K J; Penner, M J; Bugler, K E; White, T O; Younger, A S E

2016-09-01

Patients with diabetes are at increased risk of wound complications after open reduction and internal fixation of unstable ankle fractures. A fibular nail avoids large surgical incisions and allows anatomical reduction of the mortise. We retrospectively reviewed the results of fluoroscopy-guided reduction and percutaneous fibular nail fixation for unstable Weber type B or C fractures in 24 adult patients with type 1 or type 2 diabetes. The re-operation rate for wound dehiscence or other indications such as amputation, mortality and functional outcomes was determined. Two patients developed lateral side wound infection, one of whom underwent wound debridement. Three other patients required re-operation for removal of symptomatic hardware. No patient required a below-knee amputation. Six patients died during the study period for unrelated reasons. At a median follow-up of 12 months (7 to 38) the mean Short Form-36 Mental Component Score and Physical Component Score were 53.2 (95% confidence intervals (CI) 48.1 to 58.4) and 39.3 (95% CI 32.1 to 46.4), respectively. The mean Visual Analogue Score for pain was 3.1 (95% 1.4 to 4.9). The mean Ankle Osteoarthritis Scale total score was 32.9 (95% CI 16.0 to 49.7). Fluoroscopy-guided reduction and fibular nail fixation of unstable ankle fractures in patients with diabetes was associated with a low incidence of wound and overall complications, while providing effective surgical fixation. Cite this article: Bone Joint J 2016;98-B:1197-1201. ©2016 The British Editorial Society of Bone & Joint Surgery.

New light-amplifier-based detector designs for high spatial resolution and high sensitivity CBCT mammography and fluoroscopy

PubMed Central

Rudin, Stephen; Kuhls, Andrew T.; Yadava, Girijesh K.; Josan, Gaurav C.; Wu, Ye; Chityala, Ravishankar N.; Rangwala, Hussain S.; Ciprian Ionita, N.; Hoffmann, Kenneth R.; Bednarek, Daniel R.

2011-01-01

New cone-beam computed tomographic (CBCT) mammography system designs are presented where the detectors provide high spatial resolution, high sensitivity, low noise, wide dynamic range, negligible lag and high frame rates similar to features required for high performance fluoroscopy detectors. The x-ray detectors consist of a phosphor coupled by a fiber-optic taper to either a high gain image light amplifier (LA) then CCD camera or to an electron multiplying CCD. When a square-array of such detectors is used, a field-of-view (FOV) to 20 × 20 cm can be obtained where the images have pixel-resolution of 100 µm or better. To achieve practical CBCT mammography scan-times, 30 fps may be acquired with quantum limited (noise free) performance below 0.2 µR detector exposure per frame. Because of the flexible voltage controlled gain of the LA’s and EMCCDs, large detector dynamic range is also achievable. Features of such detector systems with arrays of either generation 2 (Gen 2) or 3 (Gen 3) LAs optically coupled to CCD cameras or arrays of EMCCDs coupled directly are compared. Quantum accounting analysis is done for a variety of such designs where either the lowest number of information carriers off the LA photo-cathode or electrons released in the EMCCDs per x-ray absorbed in the phosphor are large enough to imply no quantum sink for the design. These new LA- or EMCCD-based systems could lead to vastly improved CBCT mammography, ROI-CT, or fluoroscopy performance compared to systems using flat panels. PMID:21297904

New light-amplifier-based detector designs for high spatial resolution and high sensitivity CBCT mammography and fluoroscopy

NASA Astrophysics Data System (ADS)

Rudin, Stephen; Kuhls, Andrew T.; Yadava, Girijesh K.; Josan, Gaurav C.; Wu, Ye; Chityala, Ravishankar N.; Rangwala, Hussain S.; Ionita, N. Ciprian; Hoffmann, Kenneth R.; Bednarek, Daniel R.

2006-03-01

New cone-beam computed tomographic (CBCT) mammography system designs are presented where the detectors provide high spatial resolution, high sensitivity, low noise, wide dynamic range, negligible lag and high frame rates similar to features required for high performance fluoroscopy detectors. The x-ray detectors consist of a phosphor coupled by a fiber-optic taper to either a high gain image light amplifier (LA) then CCD camera or to an electron multiplying CCD. When a square-array of such detectors is used, a field-of-view (FOV) to 20 x 20 cm can be obtained where the images have pixel-resolution of 100 μm or better. To achieve practical CBCT mammography scan-times, 30 fps may be acquired with quantum limited (noise free) performance below 0.2 μR detector exposure per frame. Because of the flexible voltage controlled gain of the LA's and EMCCDs, large detector dynamic range is also achievable. Features of such detector systems with arrays of either generation 2 (Gen 2) or 3 (Gen 3) LAs optically coupled to CCD cameras or arrays of EMCCDs coupled directly are compared. Quantum accounting analysis is done for a variety of such designs where either the lowest number of information carriers off the LA photo-cathode or electrons released in the EMCCDs per x-ray absorbed in the phosphor are large enough to imply no quantum sink for the design. These new LA- or EMCCD-based systems could lead to vastly improved CBCT mammography, ROI-CT, or fluoroscopy performance compared to systems using flat panels.

Exposure of medical staff to radiation during osteosynthesis of proximal femoral fracture: descriptive analysis and comparison of different devices.

PubMed

Siedlecki, Cédric; Gauthé, Rémi; Gillibert, André; Bellenger, Kevin; Roussignol, Xavier; Ould-Slimane, Mourad

2017-10-01

The use of fluoroscopy is necessary during proximal femoral fracture (PFF) osteosynthesis. The frequency of these procedures justifies a description of radiation exposure and comparisons between different techniques and between the different surgical team members. This observational prospective and comparative study includes a series of 68 patients with PFF receiving osteosynthesis. Radiation exposure was assessed for all members of the operating team. The radiation dose measurements for the different members of the surgical team during PFF osteosynthesis were compared. The factors affecting the radiation dose were investigated. The mean active dosimeter readings for each operation were 7.39 µSv for the primary surgeon, 3.93 µSv for the assistant surgeon, 1.92 µSv for the instrument nurse, 1.25 µSv for the circulating nurse, and 0.64 µSv for the anaesthesiologist, respectively. Doses decreased significantly between these different members of the medical team (all p < 0.001). The dose also varied with patient age and BMI, as well as with fluoroscopy time and operating time, but not with type of fracture or type of osteosynthesis. Medical staff receives significantly different doses depending on their position in relation to the radiation source. Operating time and fluoroscopy time are the modifiable factors that affect the radiation dose. The radiation doses received by the different members of the medical teams involved in proximal femur osteosynthesis procedures all fall below the doses recommended by the International Commission on Radiation Units and Measurements.

Peroperative electrocardiographic control of catheter tip position during implantation of femoral venous ports.

PubMed

Gibault, Pierre; Desruennes, Eric; Bourgain, Jean-Louis

2015-01-01

Electrocardiographic (ECG) guidance has been shown to be as effective than fluoroscopy to position the tip of central venous devices close to the superior vena cava (SVC)-right atrium (RA) junction. When SVC access is contraindicated, a femoral access may be used. The aim of this prospective study is to evaluate the effectiveness of ECG guidance to position the tip of femoral ports at inferior vena cava (IVC)-RA junction. Inclusion criterion was the need for femoral port implantation. After insertion of the dilator in the femoral vein, the catheter with the guide wire inside was introduced and the ECG signal collected at the tip of the guide (Celsite™ ECG, B. Braun, Germany) or via saline injected in the catheter (Nautilus™, Perouse, France). Fluoroscopy was performed at each change of the P-wave from IVC to RA. A final X-ray was performed after withdrawing the catheter 2 cm below the first P-wave change. A total of 18 patients were included between December 2011 and June 2013. The P-wave was most often negative in IVC, biphasic when the catheter entered RA and giant and positive at the top of RA. When the catheter was withdraw 2 cm below the first biphasic P-wave the tip was just below the IVC-RA junction in 17 patients. In one patient P-wave changes were not significant and the final position was adjusted under fluoroscopy. ECG guidance is effective to assess catheter tip position during femoral port placement and avoids the need for radiological methods.

Radiation safety protocol using real-time dose reporting reduces patient exposure in pediatric electrophysiology procedures.

PubMed

Patel, Akash R; Ganley, Jamie; Zhu, Xiaowei; Rome, Jonathan J; Shah, Maully; Glatz, Andrew C

2014-10-01

Radiation exposure during pediatric catheterization is significant. We sought to describe radiation exposure and the effectiveness of radiation safety protocols in reducing exposure during catheter ablations with electrophysiology studies in children and patients with congenital heart disease. We additionally sought to identify at-risk patients. We retrospectively reviewed all interventional electrophysiology procedures performed from April 2009 to September 2011 (6 months preceding intervention, 12 months following implementation of initial radiation safety protocol, and 8 months following implementation of modified protocol). The protocols consisted of low pulse rate fluoroscopy settings, operator notification of skin entrance dose every 1,000 mGy, adjusting cameras by >5 at every 1,000 mGy, and appropriate collimation. The cohort consisted of 291 patients (70 pre-intervention, 137 after initial protocol implementation, 84 after modified protocol implementation) at a median age of 14.9 years with congenital heart disease present in 11 %. Diagnoses included atrioventricular nodal reentrant tachycardia (25 %), atrioventricular reentrant tachycardia (61 %), atrial tachycardias (12 %), and ventricular tachycardia (2 %). There were no differences between groups based on patient, arrhythmia, and procedural characteristics. Following implementation of the protocols, there were significant reductions in all measures of radiation exposure: fluoroscopy time (17.8 %), dose area product (80.2 %), skin entry dose (81.0 %), and effective dose (76.9 %), p = 0.0001. Independent predictors of increased radiation exposure included larger patient weight, longer fluoroscopy time, and lack of radiation safety protocol. Implementation of a radiation safety protocol for pediatric and congenital catheter ablations can drastically reduce radiation exposure to patients without affecting procedural success.

Effect of Audio Coaching on Correlation of Abdominal Displacement With Lung Tumor Motion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nakamura, Mitsuhiro; Narita, Yuichiro; Matsuo, Yukinori

2009-10-01

Purpose: To assess the effect of audio coaching on the time-dependent behavior of the correlation between abdominal motion and lung tumor motion and the corresponding lung tumor position mismatches. Methods and Materials: Six patients who had a lung tumor with a motion range >8 mm were enrolled in the present study. Breathing-synchronized fluoroscopy was performed initially without audio coaching, followed by fluoroscopy with recorded audio coaching for multiple days. Two different measurements, anteroposterior abdominal displacement using the real-time positioning management system and superoinferior (SI) lung tumor motion by X-ray fluoroscopy, were performed simultaneously. Their sequential images were recorded using onemore » display system. The lung tumor position was automatically detected with a template matching technique. The relationship between the abdominal and lung tumor motion was analyzed with and without audio coaching. Results: The mean SI tumor displacement was 10.4 mm without audio coaching and increased to 23.0 mm with audio coaching (p < .01). The correlation coefficients ranged from 0.89 to 0.97 with free breathing. Applying audio coaching, the correlation coefficients improved significantly (range, 0.93-0.99; p < .01), and the SI lung tumor position mismatches became larger in 75% of all sessions. Conclusion: Audio coaching served to increase the degree of correlation and make it more reproducible. In addition, the phase shifts between tumor motion and abdominal displacement were improved; however, all patients breathed more deeply, and the SI lung tumor position mismatches became slightly larger with audio coaching than without audio coaching.« less

Prospective Measurement of Patient Exposure to Radiation During Pediatric Ureteroscopy

PubMed Central

Kokorowski, Paul J.; Chow, Jeanne S.; Strauss, Keith; Pennison, Melanie; Routh, Jonathan C.; Nelson, Caleb P.

2013-01-01

Objective Little data have been reported regarding radiation exposure during pediatric endourologic procedures, including ureteroscopy (URS). We sought to measure radiation exposure during pediatric URS and identify opportunities for exposure reduction. Methods We prospectively observed URS procedures as part of a quality improvement initiative. Pre-operative patient characteristics, operative factors, fluoroscopy settings and radiation exposure were recorded. Our outcomes were entrance skin dose (ESD, in mGy) and midline dose (MLD, in mGy). Specific modifiable factors were identified as targets for potential quality improvement. Results Direct observation was performed on 56 consecutive URS procedures. Mean patient age was 14.8 ± 3.8 years (range 7.4 to 19.2); 9 children were under age 12 years. Mean ESD was 46.4 ± 48 mGy. Mean MLD was 6.2 ± 5.0 mGy. The most important major determinant of radiation dose was total fluoroscopy time (mean 2.68 ± 1.8 min) followed by dose rate setting, child anterior-posterior (AP) diameter, and source to skin distance (all p<0.01). The analysis of factors affecting exposure levels found that the use of ureteral access sheaths (p=0.01) and retrograde pyelography (p=0.04) were significantly associated with fluoroscopy time. We also found that dose rate settings were higher than recommended in up to 43% of cases and ideal C-arm positioning could have reduced exposure 14% (up to 49% in some cases). Conclusions Children receive biologically significant radiation doses during URS procedures. Several modifiable factors contribute to dose and could be targeted in efforts to implement dose reduction strategies. PMID:22341275

Radiation dose and image quality for paediatric interventional cardiology

NASA Astrophysics Data System (ADS)

Vano, E.; Ubeda, C.; Leyton, F.; Miranda, P.

2008-08-01

Radiation dose and image quality for paediatric protocols in a biplane x-ray system used for interventional cardiology have been evaluated. Entrance surface air kerma (ESAK) and image quality using a test object and polymethyl methacrylate (PMMA) phantoms have been measured for the typical paediatric patient thicknesses (4-20 cm of PMMA). Images from fluoroscopy (low, medium and high) and cine modes have been archived in digital imaging and communications in medicine (DICOM) format. Signal-to-noise ratio (SNR), figure of merit (FOM), contrast (CO), contrast-to-noise ratio (CNR) and high contrast spatial resolution (HCSR) have been computed from the images. Data on dose transferred to the DICOM header have been used to test the values of the dosimetric display at the interventional reference point. ESAK for fluoroscopy modes ranges from 0.15 to 36.60 µGy/frame when moving from 4 to 20 cm PMMA. For cine, these values range from 2.80 to 161.10 µGy/frame. SNR, FOM, CO, CNR and HCSR are improved for high fluoroscopy and cine modes and maintained roughly constant for the different thicknesses. Cumulative dose at the interventional reference point resulted 25-45% higher than the skin dose for the vertical C-arm (depending of the phantom thickness). ESAK and numerical image quality parameters allow the verification of the proper setting of the x-ray system. Knowing the increases in dose per frame when increasing phantom thicknesses together with the image quality parameters will help cardiologists in the good management of patient dose and allow them to select the best imaging acquisition mode during clinical procedures.

Real-time ultrasound transducer localization in fluoroscopy images by transfer learning from synthetic training data.

PubMed

Heimann, Tobias; Mountney, Peter; John, Matthias; Ionasec, Razvan

2014-12-01

The fusion of image data from trans-esophageal echography (TEE) and X-ray fluoroscopy is attracting increasing interest in minimally-invasive treatment of structural heart disease. In order to calculate the needed transformation between both imaging systems, we employ a discriminative learning (DL) based approach to localize the TEE transducer in X-ray images. The successful application of DL methods is strongly dependent on the available training data, which entails three challenges: (1) the transducer can move with six degrees of freedom meaning it requires a large number of images to represent its appearance, (2) manual labeling is time consuming, and (3) manual labeling has inherent errors. This paper proposes to generate the required training data automatically from a single volumetric image of the transducer. In order to adapt this system to real X-ray data, we use unlabeled fluoroscopy images to estimate differences in feature space density and correct covariate shift by instance weighting. Two approaches for instance weighting, probabilistic classification and Kullback-Leibler importance estimation (KLIEP), are evaluated for different stages of the proposed DL pipeline. An analysis on more than 1900 images reveals that our approach reduces detection failures from 7.3% in cross validation on the test set to zero and improves the localization error from 1.5 to 0.8mm. Due to the automatic generation of training data, the proposed system is highly flexible and can be adapted to any medical device with minimal efforts. Copyright © 2014 Elsevier B.V. All rights reserved.

Accuracy of ultrasound-guided nerve blocks of the cervical zygapophysial joints.

PubMed

Siegenthaler, Andreas; Mlekusch, Sabine; Trelle, Sven; Schliessbach, Juerg; Curatolo, Michele; Eichenberger, Urs

2012-08-01

Cervical zygapophysial joint nerve blocks typically are performed with fluoroscopic needle guidance. Descriptions of ultrasound-guided block of these nerves are available, but only one small study compared ultrasound with fluoroscopy, and only for the third occipital nerve. To evaluate the potential usefulness of ultrasound-guidance in clinical practice, studies that determine the accuracy of this technique using a validated control are essential. The aim of this study was to determine the accuracy of ultrasound-guided nerve blocks of the cervical zygapophysial joints using fluoroscopy as control. Sixty volunteers were studied. Ultrasound-imaging was used to place the needle to the bony target of cervical zygapophysial joint nerve blocks. The levels of needle placement were determined randomly (three levels per volunteer). After ultrasound-guided needle placement and application of 0.2 ml contrast dye, fluoroscopic imaging was performed for later evaluation by a blinded pain physician and considered as gold standard. Raw agreement, chance-corrected agreement κ, and chance-independent agreement Φ between the ultrasound-guided placement and the assessment using fluoroscopy were calculated to quantify accuracy. One hundred eighty needles were placed in 60 volunteers. Raw agreement was 87% (95% CI 81-91%), κ was 0.74 (0.64-0.83), and Φ 0.99 (0.99-0.99). Accuracy varied significantly between the different cervical nerves: it was low for the C7 medial branch, whereas all other levels showed very good accuracy. Ultrasound-imaging is an accurate technique for performing cervical zygapophysial joint nerve blocks in volunteers, except for the medial branch blocks of C7.

In Vivo Kinematics of the Tibiotalar and Subtalar Joints in Asymptomatic Subjects: A High-Speed Dual Fluoroscopy Study.

PubMed

Roach, Koren E; Wang, Bibo; Kapron, Ashley L; Fiorentino, Niccolo M; Saltzman, Charles L; Bo Foreman, K; Anderson, Andrew E

2016-09-01

Measurements of joint kinematics are essential to understand the pathomechanics of ankle disease and the effects of treatment. Traditional motion capture techniques do not provide measurements of independent tibiotalar and subtalar joint motion. In this study, high-speed dual fluoroscopy images of ten asymptomatic adults were acquired during treadmill walking at 0.5 m/s and 1.0 m/s and a single-leg, balanced heel-rise. Three-dimensional (3D) CT models of each bone and dual fluoroscopy images were used to quantify in vivo kinematics for the tibiotalar and subtalar joints. Dynamic tibiotalar and subtalar mean joint angles often exhibited opposing trends during captured stance. During both speeds of walking, the tibiotalar joint had significantly greater dorsi/plantarflexion (D/P) angular ROM than the subtalar joint while the subtalar joint demonstrated greater inversion/eversion (In/Ev) and internal/external rotation (IR/ER) than the tibiotalar joint. During balanced heel-rise, only D/P and In/Ev were significantly different between the tibiotalar and subtalar joints. Translational ROM in the anterior/posterior (AP) direction was significantly greater in the subtalar than the tibiotalar joint during walking at 0.5 m/s. Overall, our results support the long-held belief that the tibiotalar joint is primarily responsible for D/P, while the subtalar joint facilitates In/Ev and IR/ER. However, the subtalar joint provided considerable D/P rotation, and the tibiotalar joint rotated about all three axes, which, along with translational motion, suggests that each joint undergoes complex, 3D motion.

Standardized methodology for transfemoral transcatheter aortic valve replacement with the Edwards Sapien XT valve under fluoroscopy guidance.

PubMed

Kasel, Albert M; Shivaraju, Anupama; Schneider, Stephan; Krapf, Stephan; Oertel, Frank; Burgdorf, Christof; Ott, Ilka; Sumer, Christian; Kastrati, Adnan; von Scheidt, Wolfgang; Thilo, Christian

2014-09-01

To provide a simplified, standardized methodology for a successful transfemoral transcatheter aortic valve replacement (TAVR) procedure with the Sapien XT valve in patients with severe aortic stenosis (AS). TAVR is currently reserved for patients with severe, symptomatic AS who are inoperable or at high operative risk. In many institutions, TAVR is performed under general anesthesia with intubation or with conscious sedation. In addition, many institutions still use transesophageal echo (TEE) during the procedure for aortic root angulations and positioning of the valve prior to implantation. Methods. We enrolled 100 consecutive patients (mean age, 80 ± 7 years; range, 50-94 years; female n=59) with severe symptomatic AS. Annulus measurements were based on computed tomography angiograms. All patients underwent fluoroscopy-guided transfemoral TAVR with little to no sedation and without simultaneous TEE. TAVR was predominantly performed with the use of local and central analgesics; only 36% of our cohort received conscious sedation. Procedural success of TAVR was 99%. Transthoracic echocardiography before discharge excluded aortic regurgitation (AR) >2 in all patients (AR >1; n=6). In-hospital stroke rate was 6%. The vessel closure system was successfully employed in 96%. Major vascular complication rate was 1%. The 30-day mortality was 2%. Fluoroscopy-guided TAVR with the use of just analgesics with or without conscious sedation is safe and effective, and this potentially enables a more time-effective and cost-effective procedure. This paper provides simplified, stepwise guidance on how to perform transfemoral TAVR with the Sapien XT valve.

Novel System for Real-Time Integration of 3-D Echocardiography and Fluoroscopy for Image-Guided Cardiac Interventions: Preclinical Validation and Clinical Feasibility Evaluation.

PubMed

Arujuna, Aruna V; Housden, R James; Ma, Yingliang; Rajani, Ronak; Gao, Gang; Nijhof, Niels; Cathier, Pascal; Bullens, Roland; Gijsbers, Geert; Parish, Victoria; Kapetanakis, Stamatis; Hancock, Jane; Rinaldi, C Aldo; Cooklin, Michael; Gill, Jaswinder; Thomas, Martyn; O'neill, Mark D; Razavi, Reza; Rhode, Kawal S

2014-01-01

Real-time imaging is required to guide minimally invasive catheter-based cardiac interventions. While transesophageal echocardiography allows for high-quality visualization of cardiac anatomy, X-ray fluoroscopy provides excellent visualization of devices. We have developed a novel image fusion system that allows real-time integration of 3-D echocardiography and the X-ray fluoroscopy. The system was validated in the following two stages: 1) preclinical to determine function and validate accuracy; and 2) in the clinical setting to assess clinical workflow feasibility and determine overall system accuracy. In the preclinical phase, the system was assessed using both phantom and porcine experimental studies. Median 2-D projection errors of 4.5 and 3.3 mm were found for the phantom and porcine studies, respectively. The clinical phase focused on extending the use of the system to interventions in patients undergoing either atrial fibrillation catheter ablation (CA) or transcatheter aortic valve implantation (TAVI). Eleven patients were studied with nine in the CA group and two in the TAVI group. Successful real-time view synchronization was achieved in all cases with a calculated median distance error of 2.2 mm in the CA group and 3.4 mm in the TAVI group. A standard clinical workflow was established using the image fusion system. These pilot data confirm the technical feasibility of accurate real-time echo-fluoroscopic image overlay in clinical practice, which may be a useful adjunct for real-time guidance during interventional cardiac procedures.

Significant Radiation Dose Reduction in the Hybrid Operating Room Using a Novel X-ray Imaging Technology.

PubMed

van den Haak, R F F; Hamans, B C; Zuurmond, K; Verhoeven, B A N; Koning, O H J

2015-10-01

To prospectively quantify radiation dose change in aortoiliac endovascular procedures in the hybrid operating room (OR) for patients and medical staff with a novel X-ray imaging technology (ClarityIQ technology), and to assess whether procedure or fluoroscopy time or dose of iodinated contrast was affected. A prospective study including 138 patients was performed to compare radiation dose before and after installation of a novel X-ray imaging technology. Endovascular aneurysm repair (EVAR) was performed in 37 patients and an endovascular procedure for aortoiliac occlusive disease (AIOD) in 101. Patient radiation dose in air kerma (AK) and dose area product (DAP), patient demographics, and procedural data were recorded. Staff radiation dose was measured with real time personal dosimetry measurements. In both the EVAR and AIOD groups the reference system, ALX (AlluraXper FD20; Philips Healthcare, Best, the Netherlands), was compared with the upgraded X-ray system, CIQ (AlluraClarity FD20; Philips Healthcare). Procedure time, fluoroscopy time, and iodinated contrast dose were recorded. Patient radiation dose reduction in the EVAR group, in median AK, was 56% (ALX = 1,262.5 mGy; CIQ = 556.0 mGy [p < .01]); and in median DAP it was 57% (ALX = 224.4 Gycm(2) and CIQ = 95.8 Gycm(2) [p < .01]). Patient radiation dose reduction in the AIOD group, in median AK, was 76% (ALX = 1,011.0 mGy; CIQ = 248.0 mGy [p < .01]); and in median DAP it was 73% (ALX = 138.1 Gycm(2); CIQ = 38.0 Gycm(2) [p < .01]). Staff dose reduction in the EVAR group was 16% (ALX = 70.1 μSv; CIQ = 59.2 μSv [p = .43]) and in the AIOD group it was 69% (ALX = 96.2 μSv; CIQ = 30.1 μSv [p < .01]). There was no statistically significant difference between patient demographics, procedure time, fluoroscopy time, and iodinated contrast medium use in the two treatment groups before and after installation. A novel X-ray imaging technology in the hybrid OR suite resulted in a significant reduction of patient and staff radiation dose without affecting procedure length, fluoroscopy time, or use of contrast. Copyright © 2015 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

Accuracy of epicardial electroanatomic mapping and ablation of sustained ventricular tachycardia merged with heart CT scan in chronic Chagasic cardiomyopathy.

PubMed

Valdigem, Bruno Pereira; da Silva, Nilton José Carneiro; Dietrich, Cristiano Oliveira; Moreira, Dalmo; Sasdelli, Roberto; Pinto, Ibraim M; Cirenza, Claudio; de Paola, Angelo Amato Vincenzo

2010-11-01

As damage to coronary arteries is a potential complication of epicardial RF catheter ablation (EPRFCA), the procedure must be associated with coronary angiography. Chronic Chagasic cardiomiopathy (CCC) is a disease where epicardial VT are common. Eletroanatomic mapping merged with computed totmography (CT) scan data is a useful tool for mapping the endocardium, and its accuracy in guiding ablation on the epicardium was not adequately evaluated so far. Compare electronatomic map merged with Heart CT to fluoroscopy for epicardial ablation of CCC. Describe the distribution of the scars on CCC. We performed epicardial and endocardial mapping and ablation using CARTO XP V8 on eight patients and merged the map with coronary arteries CT scan using at least three landmarks. To compare the 3D image obtained with CARTO MERGE and the 2D fluoroscopic image obtained during the ablation procedure, we used computer graphic software (Inkscape™) in order to prove that the images were equivalent and to compare the distance between the catheter tip on fluoroscopy to catheter tip on 3D EA map. EPRFCA was successfully performed in all patients and they did not present recurrence for at least 3-month follow-up. The mean difference between the tip of the catheter on fluoroscopy and on the 3D model was 6.03 ± 2.09 mm. Scars were present in the epicardium and endocardium and most of patients presented with posterior wall scars and RV scar. The combination of electroanatomic map and CT coronary artery scan data is feasible and can be an important tool for EPRFCA in patients with CCC and VT.

Three-dimensional navigation is more accurate than two-dimensional navigation or conventional fluoroscopy for percutaneous sacroiliac screw fixation in the dysmorphic sacrum: a randomized multicenter study.

PubMed

Matityahu, Amir; Kahler, David; Krettek, Christian; Stöckle, Ulrich; Grutzner, Paul Alfred; Messmer, Peter; Ljungqvist, Jan; Gebhard, Florian

2014-12-01

To evaluate the accuracy of computer-assisted sacral screw fixation compared with conventional techniques in the dysmorphic versus normal sacrum. Review of a previous study database. Database of a multinational study with 9 participating trauma centers. The reviewed group included 130 patients, 72 from the navigated group and 58 from the conventional group. Of these, 109 were in the nondysmorphic group and 21 in the dysmorphic group. Placement of sacroiliac (SI) screws was performed using standard fluoroscopy for the conventional group and BrainLAB navigation software with either 2-dimensional or 3-dimensional (3D) navigation for the navigated group. Accuracy of SI screw placement by 2-dimensional and 3D navigation versus conventional fluoroscopy in dysmorphic and nondysmorphic patients, as evaluated by 6 observers using postoperative computerized tomography imaging at least 1 year after initial surgery. Intraobserver agreement was also evaluated. There were 11.9% (13/109) of patients with misplaced screws in the nondysmorphic group and 28.6% (6/21) of patients with misplaced screws in the dysmorphic group, none of which were in the 3D navigation group. Raw agreement between the 6 observers regarding misplaced screws was 32%. However, the percent overall agreement was 69.0% (kappa = 0.38, P < 0.05). The use of 3D navigation to improve intraoperative imaging for accurate insertion of SI screws is magnified in the dysmorphic proximal sacral segment. We recommend the use of 3D navigation, where available, for insertion of SI screws in patients with normal and dysmorphic proximal sacral segments. Therapeutic level I.

Fluoroscopy-Guided Percutaneous Vertebral Body Biopsy Using a Novel Drill-Powered Device: Technical Case Series

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wallace, Adam N., E-mail: wallacea@mir.wustl.edu; Pacheco, Rafael A., E-mail: pachecor@mir.wustl.edu; Tomasian, Anderanik, E-mail: tomasiana@mir.wustl.edu

2016-02-15

BackgroundA novel coaxial biopsy system powered by a handheld drill has recently been introduced for percutaneous bone biopsy. This technical note describes our initial experience performing fluoroscopy-guided vertebral body biopsies with this system, compares the yield of drill-assisted biopsy specimens with those obtained using a manual technique, and assesses the histologic adequacy of specimens obtained with drill assistance.MethodsMedical records of all single-level, fluoroscopy-guided vertebral body biopsies were reviewed. Procedural complications were documented according to the Society of Interventional Radiology classification. The total length of bone core obtained from drill-assisted biopsies was compared with that of matched manual biopsies. Pathology reportsmore » were reviewed to determine the histologic adequacy of specimens obtained with drill assistance.ResultsTwenty eight drill-assisted percutaneous vertebral body biopsies met study inclusion criteria. No acute complications were reported. Of the 86 % (24/28) of patients with clinical follow-up, no delayed complications were reported (median follow-up, 28 weeks; range 5–115 weeks). The median total length of bone core obtained from drill-assisted biopsies was 28 mm (range 8–120 mm). This was longer than that obtained from manual biopsies (median, 20 mm; range 5–45 mm; P = 0.03). Crush artifact was present in 11 % (3/28) of drill-assisted biopsy specimens, which in one case (3.6 %; 1/28) precluded definitive diagnosis.ConclusionsA drill-assisted, coaxial biopsy system can be used to safely obtain vertebral body core specimens under fluoroscopic guidance. The higher bone core yield obtained with drill assistance may be offset by the presence of crush artifact.« less

Outcomes and Direct Costs of Inferior Vena Cava Filter Placement and Retrieval within the IR and Surgical Settings.

PubMed

Makary, Mina S; Kapke, Jordan; Yildiz, Vedat; Pan, Xueliang; Dowell, Joshua D

2018-02-01

To compare the outcomes and costs of inferior vena cava (IVC) filter placement and retrieval in the interventional radiology (IR) and surgical departments at a tertiary-care center. Retrospective review was performed of 142 sequential outpatient IVC filter placements and 244 retrievals performed in the IR suite and operating room (OR) from 2013 to 2016. Patient demographic data, procedural characteristics, outcomes, and direct costs were compared between cohorts. Technical success rates of 100% were achieved for both IR and OR filter placements, and 98% of filters were successfully retrieved by IR means, compared with 83% in the OR (P < .01). Fluoroscopy time was similar for IR and OR filter insertions, but IR retrievals required half the fluoroscopy time, with an average of 9 minutes vs 18 minutes in the OR (P = .02). There was no significant difference between cohorts in the incidences of complications for filter retrievals, but more postprocedural complications were observed for OR placements (8%) vs IR placements (1%; P = .05). The most severe complication occurred during an OR filter retrieval, resulting in entanglement of the snare device and conversion to an emergent open filter removal by vascular surgery. Direct costs were approximately 20% higher for OR vs IR IVC filter placements ($2,246 vs $2,671; P = .01). Filter placements are equally successfully performed in IR and OR settings, but OR patients experienced significantly higher postprocedural complication rates and incurred higher costs. In contrast, higher technical success rates and shorter fluoroscopy times were observed for IR filter retrievals compared with those performed in the OR. Copyright © 2017 SIR. Published by Elsevier Inc. All rights reserved.

Real-time three dimensional CT and MRI to guide interventions for congenital heart disease and acquired pulmonary vein stenosis.

PubMed

Suntharos, Patcharapong; Setser, Randolph M; Bradley-Skelton, Sharon; Prieto, Lourdes R

2017-10-01

To validate the feasibility and spatial accuracy of pre-procedural 3D images to 3D rotational fluoroscopy registration to guide interventional procedures in patients with congenital heart disease and acquired pulmonary vein stenosis. Cardiac interventions in patients with congenital and structural heart disease require complex catheter manipulation. Current technology allows registration of the anatomy obtained from 3D CT and/or MRI to be overlaid onto fluoroscopy. Thirty patients scheduled for interventional procedures from 12/2012 to 8/2015 were prospectively recruited. A C-arm CT using a biplane C-arm system (Artis zee, VC14H, Siemens Healthcare) was acquired to enable 3D3D registration with pre-procedural images. Following successful image fusion, the anatomic landmarks marked in pre-procedural images were overlaid on live fluoroscopy. The accuracy of image registration was determined by measuring the distance between overlay markers and a reference point in the image. The clinical utility of the registration was evaluated as either "High", "Medium" or "None". Seventeen patients with congenital heart disease and 13 with acquired pulmonary vein stenosis were enrolled. Accuracy and benefit of registration were not evaluated in two patients due to suboptimal images. The distance between the marker and the actual anatomical location was 0-2 mm in 18 (64%), 2-4 mm in 3 (11%) and >4 mm in 7 (25%) patients. 3D3D registration was highly beneficial in 18 (64%), intermediate in 3 (11%), and not beneficial in 7 (25%) patients. 3D3D registration can facilitate complex congenital and structural interventions. It may reduce procedure time, radiation and contrast dose.

Adapting Human Videofluoroscopic Swallow Study Methods to Detect and Characterize Dysphagia in Murine Disease Models

PubMed Central

Lever, Teresa E.; Braun, Sabrina M.; Brooks, Ryan T.; Harris, Rebecca A.; Littrell, Loren L.; Neff, Ryan M.; Hinkel, Cameron J.; Allen, Mitchell J.; Ulsas, Mollie A.

2015-01-01

This study adapted human videofluoroscopic swallowing study (VFSS) methods for use with murine disease models for the purpose of facilitating translational dysphagia research. Successful outcomes are dependent upon three critical components: test chambers that permit self-feeding while standing unrestrained in a confined space, recipes that mask the aversive taste/odor of commercially-available oral contrast agents, and a step-by-step test protocol that permits quantification of swallow physiology. Elimination of one or more of these components will have a detrimental impact on the study results. Moreover, the energy level capability of the fluoroscopy system will determine which swallow parameters can be investigated. Most research centers have high energy fluoroscopes designed for use with people and larger animals, which results in exceptionally poor image quality when testing mice and other small rodents. Despite this limitation, we have identified seven VFSS parameters that are consistently quantifiable in mice when using a high energy fluoroscope in combination with the new murine VFSS protocol. We recently obtained a low energy fluoroscopy system with exceptionally high imaging resolution and magnification capabilities that was designed for use with mice and other small rodents. Preliminary work using this new system, in combination with the new murine VFSS protocol, has identified 13 swallow parameters that are consistently quantifiable in mice, which is nearly double the number obtained using conventional (i.e., high energy) fluoroscopes. Identification of additional swallow parameters is expected as we optimize the capabilities of this new system. Results thus far demonstrate the utility of using a low energy fluoroscopy system to detect and quantify subtle changes in swallow physiology that may otherwise be overlooked when using high energy fluoroscopes to investigate murine disease models. PMID:25866882

Reducing operator radiation exposure during cardiac resynchronization therapy.

PubMed

Brambilla, Marco; Occhetta, Eraldo; Ronconi, Martina; Plebani, Laura; Carriero, Alessandro; Marino, Paolo

2010-12-01

To quantify the reduction in equivalent dose at operator's hand that can be achieved by placement of a radiation-absorbing drape (RADPAD) during long-lasting cardiac resynchronization therapy (CRT) procedures. This is a prospective observational study that included 22 consecutive patients with drug-refractory heart failure who underwent implantation of a CRT device. The cases were randomly assigned to Group A (11 cases), performed without RADPAD, and to Group B (11 cases), performed using RADPAD. Dose equivalent at the examiner's hand was measured as H(p)(0.07) and as a time-adjusted H(p)(0.07) rate (mGy/min) with a direct reading dosimeter. The mean fluoroscopy time was 20.8 ± 7.7 min and the mean dose area product (DAP) was 118.6 ± 45.3 Gy cm(2). No significant differences were found between body mass index, fluoroscopy time, and DAP between patients examined with or without RADPAD. The correlation between the fluoroscopy time and the DAP was high (R(2) = 0.94, P < 0.001). Mean dose and dose rate measurement without the RADPAD at the finger and hand were H(p)(0.07) = 1.27 ± 0.47 mGy per procedure and H(p)(0.07) rate = 0.057 ± 0.011 mGy/min, respectively. The dosage was reduced with the RADPAD to H(p)(0.07) = 0.48 ± 0.20 (P < 0.05) and to H(p)(0.07) rate = 0.026 ± 0.008 (P < 0.001), respectively. A mean reduction of 54% in the equivalent dose rate to the operator's hand can be achieved with the use of RADPAD. The use of the RADPAD in CRT devices implantation will make unlikely the necessity of limiting the yearly number of implants for high volume operators.

A novel multi-planar radiography method for three dimensional pose reconstruction of the patellofemoral and tibiofemoral joints after arthroplasty.

PubMed

Amiri, Shahram; Wilson, David R; Masri, Bassam A; Sharma, Gulshan; Anglin, Carolyn

2011-06-03

Determining the 3D pose of the patella after total knee arthroplasty is challenging. The commonly used single-plane fluoroscopy is prone to large errors in the clinically relevant mediolateral direction. A conventional fixed bi-planar setup is limited in the minimum angular distance between the imaging planes necessary for visualizing the patellar component, and requires a highly flexible setup to adjust for the subject-specific geometries. As an alternative solution, this study investigated the use of a novel multi-planar imaging setup that consists of a C-arm tracked by an external optoelectric tracking system, to acquire calibrated radiographs from multiple orientations. To determine the accuracies, a knee prosthesis was implanted on artificial bones and imaged in simulated 'Supine' and 'Weightbearing' configurations. The results were compared with measures from a coordinate measuring machine as the ground-truth reference. The weightbearing configuration was the preferred imaging direction with RMS errors of 0.48 mm and 1.32 ° for mediolateral shift and tilt of the patella, respectively, the two most clinically relevant measures. The 'imaging accuracies' of the system, defined as the accuracies in 3D reconstruction of a cylindrical ball bearing phantom (so as to avoid the influence of the shape and orientation of the imaging object), showed an order of magnitude (11.5 times) reduction in the out-of-plane RMS errors in comparison to single-plane fluoroscopy. With this new method, complete 3D pose of the patellofemoral and tibiofemoral joints during quasi-static activities can be determined with a many-fold (up to 8 times) (3.4mm) improvement in the out-of-plane accuracies compared to a conventional single-plane fluoroscopy setup. Copyright © 2011 Elsevier Ltd. All rights reserved.

Balloon-augmented Onyx embolization of cerebral arteriovenous malformations using a dual-lumen balloon: a multicenter experience.

PubMed

Spiotta, Alejandro M; James, Robert F; Lowe, Stephen R; Vargas, Jan; Turk, Aquilla S; Chaudry, M Imran; Bhalla, Tarun; Janjua, Rashid M; Delaney, John J; Quintero-Wolfe, Stacey; Turner, Raymond D

2015-10-01

Conventional Onyx embolization of cerebral arteriovenous malformations (AVMs) requires lengthy procedure and fluoroscopy times to form an adequate 'proximal plug' which allows forward nidal penetration while preventing reflux and non-targeted embolization. We review our experience with balloon-augmented Onyx embolization of cerebral AVMs using a dual-lumen balloon catheter technique designed to minimize these challenges. Retrospectively acquired data for all balloon-augmented cerebral AVM embolizations performed between 2011 and 2014 were obtained from four tertiary care centers. For each procedure, at least one Scepter C balloon catheter was advanced into the AVM arterial pedicle of interest and Onyx embolization was performed through the inner lumen after balloon inflation via the outer lumen. Twenty patients underwent embolization with the balloon-augmented technique over 24 discreet treatment episodes. There were 37 total arterial pedicles embolized with the balloon-augmented technique, a mean of 1.9 per patient (range 1-5). The treated AVMs were heterogeneous in their location and size (mean 3.3±1.6 cm). Mean fluoroscopy time for each procedure was 48±26 min (28 min per embolized pedicle). Two Scepter C balloon catheter-related complications (8.3% of embolization sessions, 5.4% of pedicles embolized) were observed: an intraprocedural rupture of a feeding pedicle and fracture and retention of a catheter fragment. This multicenter experience represents the largest reported series of balloon-augmented Onyx embolization of cerebral AVMs. The technique appears safe and effective in the treatment of AVMs, allowing more efficient and controlled injection of Onyx with a decreased risk of reflux and decreased fluoroscopy times. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sailer, Anna M., E-mail: anni.sailer@mumc.nl; Haan, Michiel W. de, E-mail: m.de.haan@mumc.nl; Graaf, Rick de, E-mail: r.de.graaf@mumc.nl

PurposeThis study was designed to evaluate the feasibility of endovascular guidance by means of live fluoroscopy fusion with magnetic resonance angiography (MRA) and computed tomography angiography (CTA).MethodsFusion guidance was evaluated in 20 endovascular peripheral artery interventions in 17 patients. Fifteen patients had received preinterventional diagnostic MRA and two patients had undergone CTA. Time for fluoroscopy with MRA/CTA coregistration was recorded. Feasibility of fusion guidance was evaluated according to the following criteria: for every procedure the executing interventional radiologists recorded whether 3D road-mapping provided added value (yes vs. no) and whether PTA and/or stenting could be performed relying on the fusionmore » road-map without need for diagnostic contrast-enhanced angiogram series (CEAS) (yes vs. no). Precision of the fusion road-map was evaluated by recording maximum differences between the position of the vasculature on the virtual CTA/MRA images and conventional angiography.ResultsAverage time needed for image coregistration was 5 ± 2 min. Three-dimensional road-map added value was experienced in 15 procedures in 12 patients. In half of the patients (8/17), intervention was performed relying on the fusion road-map only, without diagnostic CEAS. In two patients, MRA roadmap showed a false-positive lesion. Excluding three patients with inordinate movements, mean difference in position of vasculature on angiography and MRA/CTA road-map was 1.86 ± 0.95 mm, implying that approximately 95 % of differences were between 0 and 3.72 mm (2 ± 1.96 standard deviation).ConclusionsFluoroscopy with MRA/CTA fusion guidance for peripheral artery interventions is feasible. By reducing the number of CEAS, this technology may contribute to enhance procedural safety.« less

Three-dimensional Image Fusion Guidance for Transjugular Intrahepatic Portosystemic Shunt Placement.

PubMed

Tacher, Vania; Petit, Arthur; Derbel, Haytham; Novelli, Luigi; Vitellius, Manuel; Ridouani, Fourat; Luciani, Alain; Rahmouni, Alain; Duvoux, Christophe; Salloum, Chady; Chiaradia, Mélanie; Kobeiter, Hicham

2017-11-01

To assess the safety, feasibility and effectiveness of image fusion guidance with pre-procedural portal phase computed tomography with intraprocedural fluoroscopy for transjugular intrahepatic portosystemic shunt (TIPS) placement. All consecutive cirrhotic patients presenting at our interventional unit for TIPS creation from January 2015 to January 2016 were prospectively enrolled. Procedures were performed under general anesthesia in an interventional suite equipped with flat panel detector, cone-beam computed tomography (CBCT) and image fusion technique. All TIPSs were placed under image fusion guidance. After hepatic vein catheterization, an unenhanced CBCT acquisition was performed and co-registered with the pre-procedural portal phase CT images. A virtual path between hepatic vein and portal branch was made using the virtual needle path trajectory software. Subsequently, the 3D virtual path was overlaid on 2D fluoroscopy for guidance during portal branch cannulation. Safety, feasibility, effectiveness and per-procedural data were evaluated. Sixteen patients (12 males; median age 56 years) were included. Procedures were technically feasible in 15 of the 16 patients (94%). One procedure was aborted due to hepatic vein catheterization failure related to severe liver distortion. No periprocedural complications occurred within 48 h of the procedure. The median dose-area product was 91 Gy cm 2 , fluoroscopy time 15 min, procedure time 40 min and contrast media consumption 65 mL. Clinical benefit of the TIPS placement was observed in nine patients (56%). This study suggests that 3D image fusion guidance for TIPS is feasible, safe and effective. By identifying virtual needle path, CBCT enables real-time multiplanar guidance and may facilitate TIPS placement.

Digital radiology using active matrix readout: amplified pixel detector array for fluoroscopy.

PubMed

Matsuura, N; Zhao, W; Huang, Z; Rowlands, J A

1999-05-01

Active matrix array technology has made possible the concept of flat panel imaging systems for radiography. In the conventional approach a thin-film circuit built on glass contains the necessary switching components (thin-film transistors or TFTs) to readout an image formed in either a phosphor or photoconductor layer. Extension of this concept to real time imaging--fluoroscopy--has had problems due to the very low noise required. A new design strategy for fluoroscopic active matrix flat panel detectors has therefore been investigated theoretically. In this approach, the active matrix has integrated thin-film amplifiers and readout electronics at each pixel and is called the amplified pixel detector array (APDA). Each amplified pixel consists of three thin-film transistors: an amplifier, a readout, and a reset TFT. The performance of the APDA approach compared to the conventional active matrix was investigated for two semiconductors commonly used to construct active matrix arrays--hydrogenated amorphous silicon and polycrystalline silicon. The results showed that with amplification close to the pixel, the noise from the external charge preamplifiers becomes insignificant. The thermal and flicker noise of the readout and the amplifying TFTs at the pixel become the dominant sources of noise. The magnitude of these noise sources is strongly dependent on the TFT geometry and its fabrication process. Both of these could be optimized to make the APDA active matrix operate at lower noise levels than is possible with the conventional approach. However, the APDA cannot be made to operate ideally (i.e., have noise limited only by the amount of radiation used) at the lowest exposure rate required in medical fluoroscopy.

Indwelling and Retrieval Complications of Denali and Celect Infrarenal Vena Cava Filters.

PubMed

Bos, Aaron S; Tullius, Thomas; Patel, Mikin; Leef, Jeffrey A; Navuluri, Rakesh; Lorenz, Jonathan M; Van Ha, Thuong G

2016-07-01

To compare indwelling and retrieval complications of Denali and Celect filters placed in the infrarenal inferior vena cava (IVC). A retrospective study was conducted over 2 years at a single institution in which 171 Denali and 162 Celect filters were placed in 333 patients with a mean age of 62.3 years ± 15.7 (161 men; 48.3%). Filter indications included venous thromboembolic disease (n = 320; 96.1%) and surgical prophylaxis (n = 13; 3.9%). A jugular approach was used to place 303 filters (91.0%). Computed tomography (CT) follow-up, complications, and retrieval data were obtained. Follow-up CT imaging was performed on 58 filters from each group with lower incidences of caval strut penetration (one vs 12) and filter tilt (one vs 15) in the Denali filter group (P = .002 and P < .001, respectively). There was no difference in incidences of breakthrough pulmonary embolism (P = .68). Retrieval attempts were performed on 43 Denali and 53 Celect filters with mean indwelling times at retrieval of 128.2 and 144.1 days, respectively (P = .40). Mean fluoroscopy time at retrieval was lower in the Denali group (3.1 min vs 6.0 min; P = .01). There were fewer cases of complex retrieval in the Denali group (n = 2 vs 10; P = .06). Tilt, fluoroscopy time, and air kerma were associated with complex retrieval (P = .04, P < .001, and P < .001, respectively). There was one Denali filter deployment complication that led to retrieval failure. This study suggests that Denali filters are associated with lower incidences of strut penetration and filter tilt as well as shorter fluoroscopy time at retrieval compared with Celect filters when placed in the infrarenal IVC. Copyright © 2016 SIR. Published by Elsevier Inc. All rights reserved.

Ultrasound-guided versus fluoroscopy-guided sacroiliac joint intra-articular injections in the noninflammatory sacroiliac joint dysfunction: a prospective, randomized, single-blinded study.

PubMed

Jee, Haemi; Lee, Ji-Hae; Park, Ki Deok; Ahn, Jaeki; Park, Yongbum

2014-02-01

To compare the short-term effects and safety of ultrasound (US)-guided sacroiliac joint (SIJ) injections with fluoroscopy (FL)-guided SIJ injections in patients with noninflammatory SIJ dysfunction. Prospective, randomized controlled trial. University hospital. Patients (N=120) with noninflammatory sacroiliac arthritis were enrolled. All procedures were performed using an FL or US apparatus. Subjects were randomly assigned to either the FL or US group. Immediately after the SIJ injections, fluoroscopy was applied to verify the correct placement of the injected medication and intravascular injections. Treatment effects and functional improvement were compared at 2 and 12 weeks after the procedures. The verbal numeric pain scale and Oswestry Disability Index improved at 2 and 12 weeks after the injections without statistical significances between groups. Of 55 US-guided injections, 48 (87.3%) were successful and 7 (12.7%) were missed. The FL-guided SIJ approach exhibited a greater accuracy (98.2%) than the US-guided approach. Vascularization around the SIJ was seen in 34 of 55 patients. Among the 34 patients, 7 had vascularization inside the joint, 23 had vascularization around the joint, and 4 had vascularization both inside and around the joint. Three cases of intravascular injections occurred in the FL group. The US-guided approach may facilitate the identification and avoidance of the critical vessels around or within the SIJ. Function and pain relief significantly improved in both groups without significant differences between groups. The US-guided approach was shown to be as effective as the FL-guided approach in treatment effects. However, diagnostic application in the SIJ may be limited because of the significantly lower accuracy rate (87.3%). Copyright © 2014 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

A posterior approach to cervical nerve root block and pulsed radiofrequency treatment for cervical radicular pain: a retrospective study.

PubMed

Xiao, Lizu; Li, Jie; Li, Disen; Yan, Dong; Yang, Jun; Wang, Daniel; Cheng, Jianguo

2015-09-01

Catastrophic complications have been reported for selective cervical nerve root block (SCNRB) or pulsed radiofrequency (PRF) via an anterolateral transforaminal approach. A posterior approach to these procedures under computed tomography guidance has been reported. Here, we report the clinical outcomes of 42 patients with chronic cervical radicular pain (CCRP) treated with a combination of SCNRB and PRF through a posterior approach under fluoroscopy guidance. We retrospectively reviewed the clinical outcomes of 42 consecutive patients with CCRP who received a combination of SCNRB and PRF through a posterior approach under fluoroscopy guidance. The thresholds of electrical stimulation and imaging of the nerve roots after contrast injection were used to evaluate the accuracy of needle placement. The numeric rating scale was used to measure the pain and numbness levels as primary clinical outcomes, which were evaluate in scheduled follow-up visits of up to 3 months. A total of 53 procedures were performed on 42 patients at the levels of C5-C8. All patients reported concordant paresthesia in response to electrical stimulation. The average sensory and motor thresholds of stimulation were 0.28 ± 0.14 and 0.36 ± 0.14 V, respectively. Injection of nonionic contrast resulted in excellent spread along the target nerve root in large majority of the procedures. The numeric rating scale scores for both pain and numbness improved significantly at 1 day, 1 week, and 1 and 3 months after the treatment. No serious adverse effects were observed in any of the patients. The posterior approach to combined SCNRB and PRF under fluoroscopy guidance appears to be safe and efficacious in the management of CCRP. Copyright © 2015 Elsevier Inc. All rights reserved.

Sensor-based electromagnetic navigation to facilitate implantation of left ventricular leads in cardiac resynchronization therapy.

PubMed

Döring, Michael; Sommer, Philipp; Rolf, Sascha; Lucas, Johannes; Breithardt, Ole A; Hindricks, Gerhard; Richter, Sergio

2015-02-01

Implantation of cardiac resynchronization therapy (CRT) devices can be challenging, time consuming, and fluoroscopy intense. To facilitate placement of left ventricular (LV) leads, a novel electromagnetic navigation system (MediGuide™, St. Jude Medical, St. Paul, MN, USA) has been developed, displaying real-time 3-D location of sensor-embedded delivery tools superimposed on prerecorded X-ray cine-loops of coronary sinus venograms. We report our experience and advanced progress in the use of this new electromagnetic tracking system to guide LV lead implantation. Between January 2012 and December 2013, 71 consecutive patients (69 ± 9 years, 76% male) were implanted with a CRT device using the new electromagnetic tracking system. Demographics, procedural data, and periprocedural adverse events were gathered. The impact of the operator's experience, optimized workflow, and improved software technology on procedural data were analyzed. LV lead implantation was successfully achieved in all patients without severe adverse events. Total procedure time measured 87 ± 37 minutes and the median total fluoroscopy time (skin-to-skin) was 4.9 (2.5-7.8) minutes with a median dose-area-product of 476 (260-1056) cGy*cm(2) . An additional comparison with conventional CRT device implantations showed a significant reduction in fluoroscopy time from 8.0 (5.8; 11.5) to 4.5 (2.8; 7.3) minutes (P = 0.016) and radiation dose from 603 (330; 969) to 338 (176; 680) cGy*cm(2) , respectively (P = 0.044 ). Use of the new navigation system enables safe and successful LV lead placement with improved orientation and significantly reduced radiation exposure during CRT implantation. © 2014 Wiley Periodicals, Inc.

Radiation hazards to vascular surgeon and scrub nurse in mobile fluoroscopy equipped hybrid vascular room

PubMed Central

Kim, Jong Bin; Lee, Jaehoon

2017-01-01

Purpose The aim of the present study was to identify the radiation hazards to vascular surgeons and scrub nurses working in mobile fluoroscopy equipped hybrid vascular operation rooms; additionally, to estimate cumulative cancer risk due to certain exposure dosages. Methods The study was conducted prospectively in 71 patients (53 men and 18 women) who had undergone vascular intervention at our hybrid vascular theater for 6 months. OEC 9900 fluoroscopy was used as mobile C-arm. Exposure dose (ED) was measured by attaching optically stimulated luminescence at in and outside of the radiation protectors. To measure X-ray scatter with the anthropomorphic phantom model, the dose was measured at 3 distances (20, 50, 100 cm) and 3 angles (horizontal, upward 45°, downward 45°) using a personal gamma radiation dosimeter, Ecotest CARD DKG-21, for 1, 3, 5, 10 minutes. Results Lifetime attributable risk of cancer was estimated using the approach of the Biological Effects of Ionizing Radiation report VII. The 6-month ED of vascular surgeons and scrub nurses were 3.85, 1.31 mSv, respectively. The attenuation rate of lead apron, neck protector and goggle were 74.6%, 60.6%, and 70.1%, respectively. All cancer incidences among surgeons and scrub nurses correspond to 2,355 and 795 per 100,000 persons. The 10-minute dose at 100-cm distance was 0.004 mSv at horizontal, 0.009 mSv at downward 45°, 0.003 mSv at upward 45°. Conclusion Although yearly radiation hazards for vascular surgeons and scrub nurses are still within safety guidelines, protection principles can never be too stringent when aiming to minimize the cumulative harmful effects. PMID:28289670

Impact of a Novel Catheter Tracking System on Radiation Exposure during the Procedural Phases of Atrial Fibrillation and Flutter Ablation.

PubMed

Malliet, Nicolas; Andrade, Jason G; Khairy, Paul; Thanh, Hien Kiem Nguyen; Venier, Sandrine; Dubuc, Marc; Dyrda, Katia; Guerra, Peter; Mondésert, Blandine; Rivard, Léna; Tadros, Rafik; Talajic, Mario; Thibault, Bernard; Roy, Denis; Macle, Laurent

2015-07-01

Fluoroscopic guidance is used to position catheters during cardiac ablation. We evaluated the impact of a novel nonfluoroscopic sensor-guided electromagnetic navigation system (MG) on radiation exposure during catheter ablation of atrial fibrillation (AF) or atrial flutter (AFL). A total of 134 consecutive patients referred for ablation of AF (n = 44) or AFL (n = 90) ablation were prospectively enrolled. In one group the MG system was used for nonfluoroscopic catheter positioning, whereas in the conventional group standard fluoroscopy was utilized. Fluoroscopy times were assessed for each stage of procedure and total radiation exposure was quantified. Patient characteristics were similar between the groups. The procedural end point was achieved in all. Median (interquartile range [IQR]) fluoroscopy times were 12.5 minutes (7.6, 17.4) MG group versus 21.5 minutes (15.3, 23.0) conventional group (P < 0.0001) for AF ablation, and 0.8 minutes (0.4, 2.5) MG group versus 9.9 minutes (5.1, 22.5) conventional group (P < 0.0001) for AFL ablation. Median (IQR) total radiation exposure (μGy·m(2)) was 1,107 (906, 2,033) MG group versus 2,835 (1,688, 3,855) conventional group (P = 0.0001) for AF ablation, and 161 (65, 537) MG group versus 1,651 (796, 4,569) conventional group (P < 0.0001) for AFL ablation. No difference in total procedural time was seen. The use of a novel nonfluoroscopic catheter tracking system is associated with a significant reduction in radiation exposure during AF and AFL ablation (61% and 90% reduction, respectively). In the era of heightened awareness of the importance of radiation reduction, this system represents a safe and efficient tool to decrease radiation exposure during electrophysiological ablation procedures. ©2015 Wiley Periodicals, Inc.

A novel technique for transcatheter patent ductus arteriosus closure in extremely preterm infants using commercially available technology.

PubMed

Zahn, Evan M; Nevin, Phillip; Simmons, Charles; Garg, Ruchira

2015-02-01

To describe a new technique for transcatheter patent ductus arteriosus (PDA) closure in extremely preterm infants using commercially available technology. PDA in premature neonates continues to be a significant clinical problem contributing importantly to both morbidity and mortality. Surgical ligation and medical therapy both have their drawbacks. Hospital records and catheterization reports of all premature neonates (< 32 weeks gestation) who underwent transcatheter PDA closure between March 2013 and February 2014 were reviewed. Particular attention was paid to procedural details, complications, and short and mid-term outcomes. Six premature infants born at gestational ages ranging between 26 and 31 weeks (median, 26 weeks) underwent attempted transcatheter PDA closure using the Amplatzer Vascular Plug II (AVP II). Median age and weight was 21.5 days (16-80 days) and 1,180 g (870-2,240 g), respectively. Fluoroscopy and echocardiography were used to guide device. Contrast angiography was not used in any patient. Complete closure was achieved in all patients with no major procedural complications. Median fluoroscopy and procedural times were 9.4 (0-19.5) and 51.5 (33-87) min, respectively. All patients were alive at the time of this report. There were no instances of device migration, left pulmonary artery (LPA), or aortic coarctation. This preliminary study demonstrates that transcatheter PDA closure can be successfully performed in extremely preterm neonates using currently available technology with a high success rate and a low incidence of complications. This report also describes a novel transvenous approach using a combination of echocardiography and judicious use of fluoroscopy to avoid arterial access in this fragile patient population. © 2014 Wiley Periodicals, Inc. © 2014 Wiley Periodicals, Inc.

Influence of needle position on lumbar segmental nerve root block selectivity.

PubMed

Wolff, André P; Groen, Gerbrand J; Wilder-Smith, Oliver H

2006-01-01

In patients with chronic low back pain radiating to the leg, segmental nerve root blocks (SNRBs) are performed to predict surgical outcome and identify the putative symptomatic spinal nerve. Epidural spread may lead to false interpretation, affecting clinical decision making. Systematic fluoroscopic analysis of epidural local anesthetic spread and its relationship to needle tip location has not been published to date. Study aims include assessment of epidural local anesthetic spread and its relationship to needle position during fluoroscopy-assisted blocks. Patients scheduled for L4, L5, and S1 blocks were included in this prospective observational study. Under fluoroscopy and electrostimulation, they received 0.5 mL of a mixture containing lidocaine 5 mg and iohexol 75 mg. X-rays with needle tip and contrast were scored for no epidural spread (grade 0), local spread epidurally (grade 1), or to adjacent nerve roots (grade 2). Sixty-five patients were analyzed for epidural spread, 62 for needle position. Grade 1 epidural spread occurred in 47% of L4 and 28% of L5 blocks and grade 2 spread in 3 blocks (5%; L5 n = 1, S1 n = 2). For lumbar blocks, the needle was most frequently found in the lateral upper half of the intervertebral foramen. Epidural spread occurred more frequently with medial needle positions (P = .06). The findings suggest (P = .06) that the risk of grade 1 and 2 lumbar epidural spread, which results in decreased SNRB selectivity, is greater with medial needle positions in the intervertebral foramen. The variability in anatomic position of the dorsal root ganglion necessitates electrostimulation to guide SNRB in addition to fluoroscopy.

Predicting tibiotalar and subtalar joint angles from skin-marker data with dual-fluoroscopy as a reference standard.

PubMed

Nichols, Jennifer A; Roach, Koren E; Fiorentino, Niccolo M; Anderson, Andrew E

2016-09-01

Evidence suggests that the tibiotalar and subtalar joints provide near six degree-of-freedom (DOF) motion. Yet, kinematic models frequently assume one DOF at each of these joints. In this study, we quantified the accuracy of kinematic models to predict joint angles at the tibiotalar and subtalar joints from skin-marker data. Models included 1 or 3 DOF at each joint. Ten asymptomatic subjects, screened for deformities, performed 1.0m/s treadmill walking and a balanced, single-leg heel-rise. Tibiotalar and subtalar joint angles calculated by inverse kinematics for the 1 and 3 DOF models were compared to those measured directly in vivo using dual-fluoroscopy. Results demonstrated that, for each activity, the average error in tibiotalar joint angles predicted by the 1 DOF model were significantly smaller than those predicted by the 3 DOF model for inversion/eversion and internal/external rotation. In contrast, neither model consistently demonstrated smaller errors when predicting subtalar joint angles. Additionally, neither model could accurately predict discrete angles for the tibiotalar and subtalar joints on a per-subject basis. Differences between model predictions and dual-fluoroscopy measurements were highly variable across subjects, with joint angle errors in at least one rotation direction surpassing 10° for 9 out of 10 subjects. Our results suggest that both the 1 and 3 DOF models can predict trends in tibiotalar joint angles on a limited basis. However, as currently implemented, neither model can predict discrete tibiotalar or subtalar joint angles for individual subjects. Inclusion of subject-specific attributes may improve the accuracy of these models. Copyright © 2016 Elsevier B.V. All rights reserved.

Impact of operator experience and training strategy on procedural outcomes with leadless pacing: Insights from the Micra Transcatheter Pacing Study.

PubMed

El-Chami, Mikhael; Kowal, Robert C; Soejima, Kyoko; Ritter, Philippe; Duray, Gabor Z; Neuzil, Petr; Mont, Lluis; Kypta, Alexander; Sagi, Venkata; Hudnall, John Harrison; Stromberg, Kurt; Reynolds, Dwight

2017-07-01

Leadless pacemaker systems have been designed to avoid the need for a pocket and transvenous lead. However, delivery of this therapy requires a new catheter-based procedure. This study evaluates the role of operator experience and different training strategies on procedural outcomes. A total of 726 patients underwent implant attempt with the Micra transcatheter pacing system (TPS; Medtronic, Minneapolis, MN, USA) by 94 operators trained in a teaching laboratory using a simulator, cadaver, and large animal models (lab training) or locally at the hospital with simulator/demo model and proctorship (hospital training). Procedure success, procedure duration, fluoroscopy time, and safety outcomes were compared between training methods and experience (implant case number). The Micra TPS procedure was successful in 99.2% of attempts and did not differ between the 55 operators trained in the lab setting and the 39 operators trained locally at the hospital (P = 0.189). Implant case number was also not a determinant of procedural success (P = 0.456). Each operator performed between one and 55 procedures. Procedure time and fluoroscopy duration decreased by 2.0% (P = 0.002) and 3.2% (P < 0.001) compared to the previous case. Major complication rate and pericardial effusion rate were not associated with case number (P = 0.755 and P = 0.620, respectively). There were no differences in the safety outcomes by training method. Among a large group of operators, implantation success was high regardless of experience. While procedure duration and fluoroscopy times decreased with implant number, complications were low and not associated with case number. Procedure and safety outcomes were similar between distinct training methodologies. © 2017 Wiley Periodicals, Inc.

Surgical Navigation Technology Based on Augmented Reality and Integrated 3D Intraoperative Imaging: A Spine Cadaveric Feasibility and Accuracy Study.

PubMed

Elmi-Terander, Adrian; Skulason, Halldor; Söderman, Michael; Racadio, John; Homan, Robert; Babic, Drazenko; van der Vaart, Nijs; Nachabe, Rami

2016-11-01

A cadaveric laboratory study. The aim of this study was to assess the feasibility and accuracy of thoracic pedicle screw placement using augmented reality surgical navigation (ARSN). Recent advances in spinal navigation have shown improved accuracy in lumbosacral pedicle screw placement but limited benefits in the thoracic spine. 3D intraoperative imaging and instrument navigation may allow improved accuracy in pedicle screw placement, without the use of x-ray fluoroscopy, and thus opens the route to image-guided minimally invasive therapy in the thoracic spine. ARSN encompasses a surgical table, a motorized flat detector C-arm with intraoperative 2D/3D capabilities, integrated optical cameras for augmented reality navigation, and noninvasive patient motion tracking. Two neurosurgeons placed 94 pedicle screws in the thoracic spine of four cadavers using ARSN on one side of the spine (47 screws) and free-hand technique on the contralateral side. X-ray fluoroscopy was not used for either technique. Four independent reviewers assessed the postoperative scans, using the Gertzbein grading. Morphometric measurements of the pedicles axial and sagittal widths and angles, as well as the vertebrae axial and sagittal rotations were performed to identify risk factors for breaches. ARSN was feasible and superior to free-hand technique with respect to overall accuracy (85% vs. 64%, P < 0.05), specifically significant increases of perfectly placed screws (51% vs. 30%, P < 0.05) and reductions in breaches beyond 4 mm (2% vs. 25%, P < 0.05). All morphometric dimensions, except for vertebral body axial rotation, were risk factors for larger breaches when performed with the free-hand method. ARSN without fluoroscopy was feasible and demonstrated higher accuracy than free-hand technique for thoracic pedicle screw placement. N/A.

Flat panel digital detector cinefluoroscopy late following SES or BMS implantation for detection of coronary stent fracture in asymptomatic patients.

PubMed

Davlouros, Periklis A; Chefneux, Corina; Xanthopoulou, Ioanna; Papathanasiou, Maria; Zaharioglou, Evaggelia; Tsigkas, Grigorios; Alexopoulos, Dimitrios

2012-05-03

Coronary stent fracture (SF), is rare and confined mainly in patients treated with sirolimus eluting stents (SES). The role of flat panel digital detector (FPDD) fluoroscopy in detecting SF has not been investigated. Assessment with FPDD fluoroscopy of asymptomatic patients, with 200 SES (Cypher, Cordis, J&J, Miami, Florida, US), and 200 bare metal stents (BMS), at 45.5 ± 15.7 and 38.4 ± 3.9 months post-stenting respectively. SF was defined as discontinuity of stent struts on fluoroscopy. Coronary angiography was reserved for patients with documented SF. Effective radiation dose was 0.26 ± 0.14 mSv. SF was depicted in 6 (3%) SES, and 1 BMS (0.5%). Stent length was an independent predictor of SF (OR 1.19, 95% CI 1.03-1.4, p=0.024). RCA location and vessel angulation were marginally significant (OR 7.7, 95% CI 0.8-74.2, p=0.077 and OR 5.1, 95% CI 0.8-34, p=0.089). Significant angiographic restenosis was detected in 4 SES (66.6%), and 1 BMS (0.5%). Re-intervention was needed in 3 (42.8%) cases, (2 SES and 1 BMS). Detection of SF with FPDD cinefluoroscopy late following coronary stenting is feasible, involves low radiation and is confined mainly to SES compared to BMS. Application of cinefluoroscopy as part of a routine stent surveillance programme in asymptomatic patients may be more appropriate in "high risk" settings (SES, long stents and adverse angiographic characteristics). The role of invasive imaging and subsequent management of such patients need further studying. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Measurement of in vitro and in vivo stent geometry and deformation by means of 3D imaging and stereo-photogrammetry.

PubMed

Zwierzak, Iwona; Cosentino, Daria; Narracott, Andrew J; Bonhoeffer, Philipp; Diaz, Vanessa; Fenner, John W; Schievano, Silvia

2014-12-01

To quantify variability of in vitro and in vivo measurement of 3D device geometry using 3D and biplanar imaging. Comparison of stent reconstruction is reported for in vitro coronary stent deployment (using micro-CT and optical stereo-photogrammetry) and in vivo pulmonary valve stent deformation (using 4DCT and biplanar fluoroscopy). Coronary stent strut length and inter-strut angle were compared in the fully deployed configuration. Local (inter-strut angle) and global (dog-boning ratio) measures of stent deformation were reported during stent deployment. Pulmonary valve stent geometry was assessed throughout the cardiac cycle by reconstruction of stent geometry and measurement of stent diameter. Good agreement was obtained between methods for assessment of coronary stent geometry with maximum disagreement of +/- 0.03 mm (length) and +/- 3 degrees (angle). The stent underwent large, non-uniform, local deformations during balloon inflation, which did not always correlate with changes in stent diameter. Three-dimensional reconstruction of the pulmonary valve stent was feasible for all frames of the fluoroscopy and for 4DCT images, with good correlation between the diameters calculated from the two methods. The largest compression of the stent during the cardiac cycle was 6.98% measured from fluoroscopy and 7.92% from 4DCT, both in the most distal ring. Quantitative assessment of stent geometry reconstructed from biplanar imaging methods in vitro and in vivo has shown good agreement with geometry reconstructed from 3D techniques. As a result of their short image acquisition time, biplanar methods may have significant advantages in the measurement of dynamic 3D stent deformation.

Virtual Simulation in Enhancing Procedural Training for Fluoroscopy-guided Lumbar Puncture: A Pilot Study.

PubMed

Ali, Saad; Qandeel, Monther; Ramakrishna, Rishi; Yang, Carina W

2018-02-01

Fluoroscopy-guided lumbar puncture (FGLP) is a basic procedural component of radiology residency and neuroradiology fellowship training. Performance of the procedure with limited experience is associated with increased patient discomfort as well as increased radiation dose, puncture attempts, and complication rate. Simulation in health care is a developing field that has potential for enhancing procedural training. We demonstrate the design and utility of a virtual reality simulator for performing FGLP. An FGLP module was developed on an ImmersiveTouch platform, which digitally reproduces the procedural environment with a hologram-like projection. From computed tomography datasets of healthy adult spines, we constructed a 3-D model of the lumbar spine and overlying soft tissues. We assigned different physical characteristics to each tissue type, which the user can experience through haptic feedback while advancing a virtual spinal needle. Virtual fluoroscopy as well as 3-D images can be obtained for procedural planning and guidance. The number of puncture attempts, the distance to the target, the number of fluoroscopic shots, and the approximate radiation dose can be calculated. Preliminary data from users who participated in the simulation were obtained in a postsimulation survey. All users found the simulation to be a realistic replication of the anatomy and procedure and would recommend to a colleague. On a scale of 1-5 (lowest to highest) rating the virtual simulator training overall, the mean score was 4.3 (range 3-5). We describe the design of a virtual reality simulator for performing FGLP and present the initial experience with this new technique. Copyright © 2018 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

Denali, Tulip, and Option Inferior Vena Cava Filter Retrieval: A Single Center Experience.

PubMed

Ramaswamy, Raja S; Jun, Emily; van Beek, Darren; Mani, Naganathan; Salter, Amber; Kim, Seung K; Akinwande, Olaguoke

2018-04-01

To compare the technical success of filter retrieval in Denali, Tulip, and Option inferior vena cava filters. A retrospective analysis of Denali, Gunther Tulip, and Option IVC filters was conducted. Retrieval failure rates, fluoroscopy time, sedation time, use of advanced retrieval techniques, and filter-related complications that led to retrieval failure were recorded. There were 107 Denali, 43 Option, and 39 Tulip filters deployed and removed with average dwell times of 93.5, 86.0, and 131 days, respectively. Retrieval failure rates were 0.9% for Denali, 11.6% for Option, and 5.1% for Tulip filters (Denali vs. Option p = 0.018; Denali vs. Tulip p = 0.159; Tulip vs. Option p = 0.045). Median fluoroscopy time for filter retrieval was 3.2 min for the Denali filter, 6.75 min for the Option filter, and 4.95 min for the Tulip filter (Denali vs. Option p < 0.01; Denali vs. Tulip p < 0.01; Tulip vs. Option p = 0.67). Advanced retrieval techniques were used in 0.9% of Denali filters, 21.1% in Option filters, and 10.8% in Tulip filters (Denali vs. Option p < 0.01; Denali vs. Tulip p < 0.01; Tulip vs. Option p < 0.01). Filter retrieval failure rates were significantly higher for the Option filter when compared to both the Denali and Tulip filters. Retrieval of the Denali filter required significantly less amount of fluoroscopy time and use of advanced retrieval techniques when compared to both the Option and Tulip filters. The findings of this study indicate easier retrieval of the Denali and Tulip IVC filters when compared to the Option filter.

A Comparison of Retrievability: Celect versus Option Filter.

PubMed

Ryu, Robert K; Desai, Kush; Karp, Jennifer; Gupta, Ramona; Evans, Alan Emerson; Rajeswaran, Shankar; Salem, Riad; Lewandowski, Robert J

2015-06-01

To compare the retrievability of 2 potentially retrievable inferior vena cava filter devices. A retrospective, institutional review board-approved study of Celect (Cook, Inc, Bloomington, Indiana) and Option (Rex Medical, Conshohocken, Pennsylvania) filters was conducted over a 33-month period at a single institution. Fluoroscopy time, significant filter tilt, use of adjunctive retrieval technique, and strut perforation in the inferior vena cava were recorded on retrieval. Fisher exact test and Mann-Whitney-Wilcoxon test were used for comparison. There were 99 Celect and 86 Option filters deployed. After an average of 2.09 months (range, 0.3-7.6 mo) and 1.94 months (range, 0.47-9.13 mo), respectively, 59% (n = 58) of patients with Celect filters and 74.7% (n = 65) of patients with Option filters presented for filter retrieval. Retrieval failure rates were 3.4% for Celect filters versus 7.7% for Option filters (P = .45). Median fluoroscopy retrieval times were 4.25 minutes for Celect filters versus 6 minutes for Option filters (P = .006). Adjunctive retrieval techniques were used in 5.4% of Celect filter retrievals versus 18.3% of Option filter retrievals (P = .045). The incidence of significant tilting was 8.9% for Celect filters versus 16.7% for Option filters (P = .27). The incidence of strut perforation was 43% for Celect filters versus 0% for Option filters (P < .0001). Retrieval rates for the Celect and Option filters were not significantly different. However, retrieval of the Option filter required a significantly increased amount of fluoroscopy time compared with the Celect filter, and there was a significantly greater usage of adjunctive retrieval techniques for the Option filter. The Celect filter had a significantly higher rate of strut perforation. Copyright © 2015 SIR. Published by Elsevier Inc. All rights reserved.

CT fluoroscopy-guided core needle biopsy of anterior mediastinal masses.

PubMed

Iguchi, T; Hiraki, T; Matsui, Y; Fujiwara, H; Sakurai, J; Masaoka, Y; Uka, M; Tanaka, T; Gobara, H; Kanazawa, S

2018-02-01

To retrospectively evaluate the safety, diagnostic yield, and risk factors of diagnostic failure of computed tomography (CT) fluoroscopy-guided biopsies of anterior mediastinal masses. Biopsy procedures and results of anterior mediastinal masses in 71 patients (32 women/39 men; mean [±standard deviation] age, 53.8±20.0years; range, 14-88years) were analyzed. Final diagnoses were based on surgical outcomes, imaging findings, or clinical follow-up findings. The biopsy results were compared with the final diagnosis, and the biopsy procedures grouped by pathologic findings into diagnostic success and failure groups. Multiple putative risk factors for diagnostic failure were then assessed. Seventy-one biopsies (71 masses; mean size, 67.5±27.3mm; range 8.6-128.2mm) were analyzed. We identified 17 grade 1 and one grade 2 adverse events (25.4% overall) according to the National Cancer Institute Common Terminology Criteria for Adverse Events version 4.0. Sixty-nine biopsies (97.2%) provided samples fit for pathologic analysis. Diagnostic failure was found for eight (11.3%) masses; the 63 masses diagnosed successfully included thymic carcinoma (n=17), lung cancer (n=14), thymoma (n=12), malignant lymphoma (n=11), germ cell tumor (n=3), and others (n=6). Using a thinner needle (i.e., a 20-gauge needle) was the sole significant risk factor for diagnostic failure (P=0.039). CT fluoroscopy-guided biopsy of anterior mediastinal masses was safe and had a high diagnostic yield; however, using a thinner biopsy needle significantly increased the risk of a failed diagnosis. Copyright © 2017 Éditions françaises de radiologie. Published by Elsevier Masson SAS. All rights reserved.

Interventional spinal procedures guided and controlled by a 3D rotational angiographic unit.

PubMed

Pedicelli, Alessandro; Verdolotti, Tommaso; Pompucci, Angelo; Desiderio, Flora; D'Argento, Francesco; Colosimo, Cesare; Bonomo, Lorenzo

2011-12-01

The aim of this paper is to demonstrate the usefulness of 2D multiplanar reformatting images (MPR) obtained from rotational acquisitions with cone-beam computed tomography technology during percutaneous extra-vascular spinal procedures performed in the angiography suite. We used a 3D rotational angiographic unit with a flat panel detector. MPR images were obtained from a rotational acquisition of 8 s (240 images at 30 fps), tube rotation of 180° and after post-processing of 5 s by a local work-station. Multislice CT (MSCT) is the best guidance system for spinal approaches permitting direct tomographic visualization of each spinal structure. Many operators, however, are trained with fluoroscopy, it is less expensive, allows real-time guidance, and in many centers the angiography suite is more frequently available for percutaneous procedures. We present our 6-year experience in fluoroscopy-guided spinal procedures, which were performed under different conditions using MPR images. We illustrate cases of vertebroplasty, epidural injections, selective foraminal nerve root block, facet block, percutaneous treatment of disc herniation and spine biopsy, all performed with the help of MPR images for guidance and control in the event of difficult or anatomically complex access. The integrated use of "CT-like" MPR images allows the execution of spinal procedures under fluoroscopy guidance alone in all cases of dorso-lumbar access, with evident limitation of risks and complications, and without need for recourse to MSCT guidance, thus eliminating CT-room time (often bearing high diagnostic charges), and avoiding organizational problems for procedures that need, for example, combined use of a C-arm in the CT room.

Application of newly developed Fluoro-QC software for image quality evaluation in cardiac X-ray systems.

PubMed

Oliveira, M; Lopez, G; Geambastiani, P; Ubeda, C

2018-05-01

A quality assurance (QA) program is a valuable tool for the continuous production of optimal quality images. The aim of this paper is to assess a newly developed automatic computer software for image quality (IR) evaluation in fluoroscopy X-ray systems. Test object images were acquired using one fluoroscopy system, Siemens Axiom Artis model (Siemens AG, Medical Solutions Erlangen, Germany). The software was developed as an ImageJ plugin. Two image quality parameters were assessed: high-contrast spatial resolution (HCSR) and signal-to-noise ratio (SNR). The time between manual and automatic image quality assessment procedures were compared. The paired t-test was used to assess the data. p Values of less than 0.05 were considered significant. The Fluoro-QC software generated faster IQ evaluation results (mean = 0.31 ± 0.08 min) than manual procedure (mean = 4.68 ± 0.09 min). The mean difference between techniques was 4.36 min. Discrepancies were identified in the region of interest (ROI) areas drawn manually with evidence of user dependence. The new software presented the results of two tests (HCSR = 3.06, SNR = 5.17) and also collected information from the DICOM header. Significant differences were not identified between manual and automatic measures of SNR (p value = 0.22) and HCRS (p value = 0.46). The Fluoro-QC software is a feasible, fast and free to use method for evaluating imaging quality parameters on fluoroscopy systems. Copyright © 2017 The College of Radiographers. Published by Elsevier Ltd. All rights reserved.

Surface ECG and Fluoroscopy are Not Predictive of Right Ventricular Septal Lead Position Compared to Cardiac CT.

PubMed

Rowe, Matthew K; Moore, Peter; Pratap, Jit; Coucher, John; Gould, Paul A; Kaye, Gerald C

2017-05-01

Controversy exists regarding the optimal lead position for chronic right ventricular (RV) pacing. Placing a lead at the RV septum relies upon fluoroscopy assisted by a surface 12-lead electrocardiogram (ECG). We compared the postimplant lead position determined by ECG-gated multidetector contrast-enhanced computed tomography (MDCT) with the position derived from the surface 12-lead ECG. Eighteen patients with permanent RV leads were prospectively enrolled. Leads were placed in the RV septum (RVS) in 10 and the RV apex (RVA) in eight using fluoroscopy with anteroposterior and left anterior oblique 30° views. All patients underwent MDCT imaging and paced ECG analysis. ECG criteria were: QRS duration; QRS axis; positive or negative net QRS amplitude in leads I, aVL, V1, and V6; presence of notching in the inferior leads; and transition point in precordial leads at or after V4. Of the 10 leads implanted in the RVS, computed tomography (CT) imaging revealed seven to be at the anterior RV wall, two at the anteroseptal junction, and one in the true septum. For the eight RVA leads, four were anterior, two septal, and two anteroseptal. All leads implanted in the RVS met at least one ECG criteria (median 3, range 1-6). However, no criteria were specific for septal position as judged by MDCT. Mean QRS duration was 160 ± 24 ms in the RVS group compared with 168 ± 14 ms for RVA pacing (P = 0.38). We conclude that the surface ECG is not sufficiently accurate to determine RV septal lead tip position compared to cardiac CT. © 2017 Wiley Periodicals, Inc.

Multimode C-arm fluoroscopy, tomosynthesis, and cone-beam CT for image-guided interventions: from proof of principle to patient protocols

NASA Astrophysics Data System (ADS)

Siewerdsen, J. H.; Daly, M. J.; Bachar, G.; Moseley, D. J.; Bootsma, G.; Brock, K. K.; Ansell, S.; Wilson, G. A.; Chhabra, S.; Jaffray, D. A.; Irish, J. C.

2007-03-01

High-performance intraoperative imaging is essential to an ever-expanding scope of therapeutic procedures ranging from tumor surgery to interventional radiology. The need for precise visualization of bony and soft-tissue structures with minimal obstruction to the therapy setup presents challenges and opportunities in the development of novel imaging technologies specifically for image-guided procedures. Over the past ~5 years, a mobile C-arm has been modified in collaboration with Siemens Medical Solutions for 3D imaging. Based upon a Siemens PowerMobil, the device includes: a flat-panel detector (Varian PaxScan 4030CB); a motorized orbit; a system for geometric calibration; integration with real-time tracking and navigation (NDI Polaris); and a computer control system for multi-mode fluoroscopy, tomosynthesis, and cone-beam CT. Investigation of 3D imaging performance (noise-equivalent quanta), image quality (human observer studies), and image artifacts (scatter, truncation, and cone-beam artifacts) has driven the development of imaging techniques appropriate to a host of image-guided interventions. Multi-mode functionality presents a valuable spectrum of acquisition techniques: i.) fluoroscopy for real-time 2D guidance; ii.) limited-angle tomosynthesis for fast 3D imaging (e.g., ~10 sec acquisition of coronal slices containing the surgical target); and iii.) fully 3D cone-beam CT (e.g., ~30-60 sec acquisition providing bony and soft-tissue visualization across the field of view). Phantom and cadaver studies clearly indicate the potential for improved surgical performance - up to a factor of 2 increase in challenging surgical target excisions. The C-arm system is currently being deployed in patient protocols ranging from brachytherapy to chest, breast, spine, and head and neck surgery.

Advanced electrophysiologic mapping systems: an evidence-based analysis.

PubMed

2006-01-01

To assess the effectiveness, cost-effectiveness, and demand in Ontario for catheter ablation of complex arrhythmias guided by advanced nonfluoroscopy mapping systems. Particular attention was paid to ablation for atrial fibrillation (AF). Tachycardia Tachycardia refers to a diverse group of arrhythmias characterized by heart rates that are greater than 100 beats per minute. It results from abnormal firing of electrical impulses from heart tissues or abnormal electrical pathways in the heart because of scars. Tachycardia may be asymptomatic, or it may adversely affect quality of life owing to symptoms such as palpitations, headaches, shortness of breath, weakness, dizziness, and syncope. Atrial fibrillation, the most common sustained arrhythmia, affects about 99,000 people in Ontario. It is associated with higher morbidity and mortality because of increased risk of stroke, embolism, and congestive heart failure. In atrial fibrillation, most of the abnormal arrhythmogenic foci are located inside the pulmonary veins, although the atrium may also be responsible for triggering or perpetuating atrial fibrillation. Ventricular tachycardia, often found in patients with ischemic heart disease and a history of myocardial infarction, is often life-threatening; it accounts for about 50% of sudden deaths. Treatment of Tachycardia The first line of treatment for tachycardia is antiarrhythmic drugs; for atrial fibrillation, anticoagulation drugs are also used to prevent stroke. For patients refractory to or unable to tolerate antiarrhythmic drugs, ablation of the arrhythmogenic heart tissues is the only option. Surgical ablation such as the Cox-Maze procedure is more invasive. Catheter ablation, involving the delivery of energy (most commonly radiofrequency) via a percutaneous catheter system guided by X-ray fluoroscopy, has been used in place of surgical ablation for many patients. However, this conventional approach in catheter ablation has not been found to be effective for the treatment of complex arrhythmias such as chronic atrial fibrillation or ventricular tachycardia. Advanced nonfluoroscopic mapping systems have been developed for guiding the ablation of these complex arrhythmias. Four nonfluoroscopic advanced mapping systems have been licensed by Health Canada: CARTO EP mapping System (manufactured by Biosense Webster, CA) uses weak magnetic fields and a special mapping/ablation catheter with a magnetic sensor to locate the catheter and reconstruct a 3-dimensional geometry of the heart superimposed with colour-coded electric potential maps to guide ablation. EnSite System (manufactured by Endocardial Solutions Inc., MN) includes a multi-electrode non-contact catheter that conducts simultaneous mapping. A processing unit uses the electrical data to computes more than 3,000 isopotential electrograms that are displayed on a reconstructed 3-dimensional geometry of the heart chamber. The navigational system, EnSite NavX, can be used separately with most mapping catheters. The LocaLisa Intracardiac System (manufactured by Medtronics Inc, MN) is a navigational system that uses an electrical field to locate the mapping catheter. It reconstructs the location of the electrodes on the mapping catheter in 3-dimensional virtual space, thereby enabling an ablation catheter to be directed to the electrode that identifies abnormal electric potential. Polar Constellation Advanced Mapping Catheter System (manufactured by Boston Scientific, MA) is a multielectrode basket catheter with 64 electrodes on 8 splines. Once deployed, each electrode is automatically traced. The information enables a 3-dimensional model of the basket catheter to be computed. Colour-coded activation maps are reconstructed online and displayed on a monitor. By using this catheter, a precise electrical map of the atrium can be obtained in several heartbeats. A systematic search of Cochrane, MEDLINE and EMBASE was conducted to identify studies that compared ablation guided by any of the advanced systems to fluoroscopy-guided ablation of tachycardia. English-language studies with sample sizes greater than or equal to 20 that were published between 2000 and 2005 were included. Observational studies on safety of advanced mapping systems and fluoroscopy were also included. Outcomes of interest were acute success, defined as termination of arrhythmia immediately following ablation; long-term success, defined as being arrhythmia free at follow-up; total procedure time; fluoroscopy time; radiation dose; number of radiofrequency pulses; complications; cost; and the cost-effectiveness ratio. Quality of the individual studies was assessed using established criteria. Quality of the overall evidence was determined by applying the GRADE evaluation system. (3) Qualitative synthesis of the data was performed. Quantitative analysis using Revman 4.2 was performed when appropriate. Quality of the Studies Thirty-four studies met the inclusion criteria. These comprised 18 studies on CARTO (4 randomized controlled trials [RCTs] and 14 non-RCTs), 3 RCTs on EnSite NavX, 4 studies on LocaLisa Navigational System (1 RCT and 3 non-RCTs), 2 studies on EnSite and CARTO, 1 on Polar Constellation basket catheter, and 7 studies on radiation safety. The quality of the studies ranged from moderate to low. Most of the studies had small sample sizes with selection bias, and there was no blinding of patients or care providers in any of the studies. Duration of follow-up ranged from 6 weeks to 29 months, with most having at least 6 months of follow-up. There was heterogeneity with respect to the approach to ablation, definition of success, and drug management before and after the ablation procedure. Evidence is based on a small number of small RCTS and non-RCTS with methodological flaws.Advanced nonfluoroscopy mapping/navigation systems provided real time 3-dimensional images with integration of anatomic and electrical potential information that enable better visualization of areas of interest for ablationAdvanced nonfluoroscopy mapping/navigation systems appear to be safe; they consistently shortened the fluoroscopy duration and radiation exposure.Evidence suggests that nonfluoroscopy mapping and navigation systems may be used as adjuncts to rather than replacements for fluoroscopy in guiding the ablation of complex arrhythmias.Most studies showed a nonsignificant trend toward lower overall failure rate for advanced mapping-guided ablation compared with fluoroscopy-guided mapping.Pooled analyses of small RCTs and non-RCTs that compared fluoroscopy- with nonfluoroscopy-guided ablation of atrial fibrillation and atrial flutter showed that advanced nonfluoroscopy mapping and navigational systems:Yielded acute success rates of 69% to 100%, not significantly different from fluoroscopy ablation.Had overall failure rates at 3 months to 19 months of 1% to 40% (median 25%).Resulted in a 10% relative reduction in overall failure rate for advanced mapping guided-ablation compared to fluoroscopy guided ablation for the treatment of atrial fibrillation.Yielded added benefit over fluoroscopy in guiding the ablation of complex arrhythmia. The advanced systems were shown to reduce the arrhythmia burden and the need for antiarrhythmic drugs in patients with complex arrhythmia who had failed fluoroscopy-guided ablationBased on predominantly observational studies, circumferential PV ablation guided by a nonfluoroscopy system was shown to do the following:Result in freedom from atrial fibrillation (with or without antiarrhythmic drug) in 75% to 95% of patients (median 79%). This effect was maintained up to 28 months.Result in freedom from atrial fibrillation without antiarrhythmic drugs in 47% to 95% of patients (median 63%).Improve patient survival at 28 months after the procedure as compared with drug therapy.Require special skills; patient outcomes are operator dependent, and there is a significant learning curve effect.Complication rates of pulmonary vein ablation guided by an advanced mapping/navigation system ranged from 0% to 10% with a median of 6% during a follow-up period of 6 months to 29 months.The complication rate of the study with the longest follow-up was 8%.The most common complications of advanced catheter-guided ablation were stroke, transient ischemic attack, cardiac tamponade, myocardial infarction, atrial flutter, congestive heart failure, and pulmonary vein stenosis. A small number of cases with fatal atrial-esophageal fistula had been reported and were attributed to the high radiofrequency energy used rather than to the advanced mapping systems. An Ontario-based economic analysis suggests that the cumulative incremental upfront costs of catheter ablation of atrial fibrillation guided by advanced nonfluoroscopy mapping could be recouped in 4.7 years through cost avoidance arising from less need for antiarrhythmic drugs and fewer hospitalization for stroke and heart failure. Expert Opinion Expert consultants to the Medical Advisory Secretariat noted the following: Nonfluoroscopy mapping is not necessary for simple ablation procedures (e.g., typical flutter). However, it is essential in the ablation of complex arrhythmias including these:Symptomatic, drug-refractory atrial fibrillationArrhythmias in people who have had surgery for congenital heart disease (e.g., macro re-entrant tachycardia in people who have had surgery for congenital heart disease).Ventricular tachycardia due to myocardial infarctionAtypical atrial flutterAdvanced mapping systems represent an enabling technology in the ablation of complex arrhythmias. The ablation of these complex cases would not have been feasible or advisable with fluoroscopy-guided ablation and, therefore, comparative studies would not be feasible or ethical in such cases. (ABSTRACT TRUNCATED)

Eye lens exposure to medical staff during endoscopic retrograde cholangiopancreatography.

PubMed

Zagorska, A; Romanova, K; Hristova-Popova, J; Vassileva, J; Katzarov, K

2015-11-01

The paper presents a study of the radiation doses to eye lens of medical staff during endoscopic retrograde cholangiopancreatography (ERCP) procedures performed in a busy gastroenterology department. For each procedure the dose equivalent to the eye, exposure time, dose rate, Kerma Area Product and fluoroscopy time were recorded. Measurements were performed for a period of two months in four main positions of the operating staff, and then extrapolated to estimate annual doses. The fluoroscopy time per ERCP procedure varied between 1.0 min and 28.8 min, with a mean value of 4.6 min. The calculated mean eye dose per procedure varied between 34.9 μSv and 93.3 μSv. The results demonstrated that if eye protection is not used, annual doses to the eye lens of the gastroenterologist performing the procedure and the anesthesiologist can exceed the dose limit of 20 mSv per year. Copyright © 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Quantification of in vivo implant wear in total knee replacement from dynamic single plane radiography

NASA Astrophysics Data System (ADS)

Teeter, Matthew G.; Seslija, Petar; Milner, Jaques S.; Nikolov, Hristo N.; Yuan, Xunhua; Naudie, Douglas D. R.; Holdsworth, David W.

2013-05-01

An in vivo method to measure wear in total knee replacements was developed using dynamic single-plane fluoroscopy. A dynamic, anthropomorphic total knee replacement phantom with interchangeable, custom-fabricated components of known wear volume was created, and dynamic imaging was performed. For each frame of the fluoroscopy data, the relative location of the femoral and tibial components were determined, and the apparent intersection of the femoral component with the tibial insert was used to calculate wear volume, wear depth, and frequency of intersection. No difference was found between the measured and true wear volumes. The precision of the measurements was ±39.7 mm3 for volume and ±0.126 mm for wear depth. The results suggest the system is capable of tracking wear volume changes across multiple time points in patients. As a dynamic technique, this method can provide both kinematic and wear measurements that may be useful for evaluating new implant designs for total knee replacements.

Learning without labeling: domain adaptation for ultrasound transducer localization.

PubMed

Heimann, Tobias; Mountney, Peter; John, Matthias; Ionasec, Razvan

2013-01-01

The fusion of image data from trans-esophageal echography (TEE) and X-ray fluoroscopy is attracting increasing interest in minimally-invasive treatment of structural heart disease. In order to calculate the needed transform between both imaging systems, we employ a discriminative learning based approach to localize the TEE transducer in X-ray images. Instead of time-consuming manual labeling, we generate the required training data automatically from a single volumetric image of the transducer. In order to adapt this system to real X-ray data, we use unlabeled fluoroscopy images to estimate differences in feature space density and correct covariate shift by instance weighting. An evaluation on more than 1900 images reveals that our approach reduces detection failures by 95% compared to cross validation on the test set and improves the localization error from 1.5 to 0.8 mm. Due to the automatic generation of training data, the proposed system is highly flexible and can be adapted to any medical device with minimal efforts.

Experiment in Assessing Color Separation Techniques for Identifying Small Density Variations in Tires

DOT National Transportation Integrated Search

1972-07-01

An experimental color system was tested as an adjunct to the X-ray fluoroscopy system already in use. Shades of gray were translated into various colors as a means of enhancing small defects normally observed with difficulty, and to provide for more ...

Transforaminal Lumbar Interbody Fusion with Rigid Interspinous Process Fixation: A Learning Curve Analysis of a Surgeon Team's First 74 Cases.

PubMed

Doherty, Patrick; Welch, Arthur; Tharpe, Jason; Moore, Camille; Ferry, Chris

2017-05-30

Studies have shown that a significant learning curve may be associated with adopting minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) with bilateral pedicle screw fixation (BPSF). Accordingly, several hybrid TLIF techniques have been proposed as surrogates to the accepted BPSF technique, asserting that less/fewer fixation(s) or less disruptive fixation may decrease the learning curve while still maintaining the minimally disruptive benefits. TLIF with interspinous process fixation (ISPF) is one such surrogate procedure. However, despite perceived ease of adaptability given the favorable proximity of the spinous processes, no evidence exists demonstrating whether or not the technique may possess its own inherent learning curve. The purpose of this study was to determine whether an intraoperative learning curve for one- and two-level TLIF + ISPF may exist for a single lead surgeon. Seventy-four consecutive patients who received one- or two-Level TLIF with rigid ISPF by a single lead surgeon were retrospectively reviewed. It was the first TLIF + ISPF case series for the lead surgeon. Intraoperative blood loss (EBL), hospitalization length-of-stay (LOS), fluoroscopy time, and postoperative complications were collected. EBL, LOS, and fluoroscopy time were modeled as a function of case number using multiple linear regression methods. A change point was included in each model to allow the trajectory of the outcomes to change during the duration of the case series. These change points were determined using profile likelihood methods. Models were fit using the maximum likelihood estimates for the change points. Age, sex, body mass index (BMI), and the number of treated levels were included as covariates. EBL, LOS, and fluoroscopy time did not significantly differ by age, sex, or BMI (p ≥ 0.12). Only EBL differed significantly by the number of levels (p = 0.026). The case number was not a significant predictor of EBL, LOS, or fluoroscopy time (p ≥ 0.21). At the time of data collection (mean time from surgery: 13.3 months), six patients had undergone revision due to interbody migration. No ISPF device complications were observed. Study outcomes support the ideal that TLIF + ISPF can be a readily adopted procedure without a significant intraoperative learning curve. However, the authors emphasize that further assessment of long-term healing outcomes is essential in fully characterizing both the efficacy and the indication learning curve for the TLIF + ISPF technique.

21 CFR 892.1670 - Spot-film device.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Spot-film device. 892.1670 Section 892.1670 Food... DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1670 Spot-film device. (a) Identification. A spot-film... medical purposes to position a radiographic film cassette to obtain radiographs during fluoroscopy. (b...

21 CFR 892.1670 - Spot-film device.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Spot-film device. 892.1670 Section 892.1670 Food... DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1670 Spot-film device. (a) Identification. A spot-film... medical purposes to position a radiographic film cassette to obtain radiographs during fluoroscopy. (b...

21 CFR 892.1670 - Spot-film device.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Spot-film device. 892.1670 Section 892.1670 Food... DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1670 Spot-film device. (a) Identification. A spot-film... medical purposes to position a radiographic film cassette to obtain radiographs during fluoroscopy. (b...

21 CFR 892.1670 - Spot-film device.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Spot-film device. 892.1670 Section 892.1670 Food... DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1670 Spot-film device. (a) Identification. A spot-film... medical purposes to position a radiographic film cassette to obtain radiographs during fluoroscopy. (b...

Medical simulation in interventional cardiology: "More research is needed".

PubMed

Tajti, Peter; Brilakis, Emmanouil S

2018-05-01

Medical simulation is being used for training fellows to perform coronary angiography. Medical simulation training was associated with 2 min less fluoroscopy time per case after adjustment. Whether medical simulation really works needs to be evaluated in additional, well-designed and executed clinical studies. © 2018 Wiley Periodicals, Inc.

21 CFR 892.1670 - Spot-film device.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Spot-film device. 892.1670 Section 892.1670 Food... DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1670 Spot-film device. (a) Identification. A spot-film... medical purposes to position a radiographic film cassette to obtain radiographs during fluoroscopy. (b...

Analysis of Patients' X-ray Exposure in 146 Percutaneous Radiologic Gastrostomies.

PubMed

Petersen, Tim-Ole; Reinhardt, Martin; Fuchs, Jochen; Gosch, Dieter; Surov, Alexey; Stumpp, Patrick; Kahn, Thomas; Moche, Michael

2017-09-01

Purpose  Analysis of patient´s X-ray exposure during percutaneous radiologic gastrostomies (PRG) in a larger population. Materials and Methods  Data of primary successful PRG-procedures, performed between 2004 and 2015 in 146 patients, were analyzed regarding the exposition to X-ray. Dose-area-product (DAP), dose-length-product (DLP) respectively, and fluoroscopy time (FT) were correlated with the used x-ray systems (Flatpanel Detector (FD) vs. Image Itensifier (BV)) and the necessity for periprocedural placement of a nasogastric tube. Additionally, the effective X-ray dose for PRG placement using fluoroscopy (DL), computed tomography (CT), and cone beam CT (CBCT) was estimated using a conversion factor. Results  The median DFP of PRG-placements under fluoroscopy was 163 cGy*cm 2 (flat panel detector systems: 155 cGy*cm 2 ; X-ray image intensifier: 175 cGy*cm 2 ). The median DLZ was 2.2 min. Intraprocedural placement of a naso- or orogastric probe (n = 68) resulted in a significant prolongation of the median DLZ to 2.5 min versus 2 min in patients with an already existing probe. In addition, dose values were analyzed in smaller samples of patients in which the PRG was placed under CBCT (n = 7, median DFP = 2635 cGy*cm 2 ), or using CT (n = 4, median DLP = 657 mGy*cm). Estimates of the median DFP and DLP showed effective doses of 0.3 mSv for DL-assisted placements (flat panel detector 0.3 mSv, X-ray image converter 0.4 mSv), 7.9 mSv using a CBCT - flat detector, and 9.9 mSv using CT. This corresponds to a factor 26 of DL versus CBCT, or a factor 33 of DL versus CT. Conclusion  In order to minimize X-ray exposure during PRG-procedures for patients and staff, fluoroscopically-guided interventions should employ flat detector systems with short transmittance sequences in low dose mode and with slow image frequency. Series recordings can be dispensed with. The intraprocedural placement of a naso- or orogastric probe significantly extends FT, but has little effect on the overall dose of the intervention. Due to the significantly higher X-ray exposure, the use of a CBCT as well as PRG-placements using CT should be limited to clinically absolutely necessary exceptions with strict indication. Key Points   · Fluoroscopically-guided PRG placements are interventions with low X-ray exposure.. · X-ray exposure from fluoroscopy is lower using flat panel detector systems as compared to image intensifier systems.. · The concomitant placement of an oro- or nasogastric probe extends the fluoroscopy time.. · Gastric probe placement is worthwhile to prevent the premature use of the significantly radiation-intensive CT.. · The use of the C-arm CT or the CT increases the beam exposure by 26 or 33 times, respectively.. · The PRG placement using C-arm CT and CT should only be performed in exceptional cases.. Citation Format · Petersen TO, Reinhardt M, Fuchs J et al. Analysis of Patients' X-ray Exposure in 146 Percutaneous Radiologic Gastrostomies. Fortschr Röntgenstr 2017; 189: 820 - 827. © Georg Thieme Verlag KG Stuttgart · New York.

Nuclear Science Symposium, 27th, and Symposium on Nuclear Power Systems, 12th, Orlando, Fla., November 5-7, 1980, Proceedings

NASA Technical Reports Server (NTRS)

Martini, M.

1981-01-01

Advances in instrumentation for use in nuclear-science studies are described. Consideration is given to medical instrumentation, computerized fluoroscopy, environmental instrumentation, data acquisition techniques, semiconductor detectors, microchannel plates and photomultiplier tubes, reactor instrumentation, neutron detectors and proportional counters, and space instrumentation.

59th Medical Wing Office of the Chief Scientists Research Highlights Flyer-April 2016

DTIC Science & Technology

2016-05-09

Occlusion of the Aorta (REBOA Inventors: Col Todd Rasmussen, MC, USAF MEDCOM USAMRMC and Jonathan Eliason, MD, University of Michigan) Is a fluoroscopy-free...thoracic aortic balloon occlusion system to control non-compressible hemorrh and assess the effect of an occluding aorta . Research to develop the

An adjustable sterile lead apron for radiation protection during angiography.

PubMed

Grollman, J H; Sanchez, J L

1979-08-01

A simple sterile lead apron can be mounted directly on any vertical-beam image-intensifier housing and readjusted by the angiographer to shield himself from scatter during fluoroscopy and cineangiocardiography, even if the image intensifier is titled in the longitudinal plane. Properly placed, the apron effectively reduces exposed due to scatter.

Development of an Injectable Salmon Fibrinogen-Thrombin Matrix to Enhance Healing of Compound Fractures of Extremities

DTIC Science & Technology

2011-10-01

of bone regeneration in animals treated with different implantable matrix. The material to be tested in this project is a salmon fibrin matrix... Buprenorphine and metacam (Meloxicam) are also administered at the time of surgery for short term pain relief. Fluoroscopy is performed before and after injury

The era of ultrasonography during laparoscopic cholecystectomy.

PubMed

Onders, Raymond P; Hallowell, Peter T

2005-03-01

The use of ultrasound cholangiography during cholecystectomy has been well described. This study was undertaken to assess the use of the umbilical port exclusively for ultrasound and to assess its employment on the use of fluoroscopy resources. In addition, we also looked at the increased use of ultrasound from 2000 to 2004. The use of imaging techniques during all cholecystectomies was analyzed from January 2000 to July 2001 for one surgeon and compared with that surgeon's present use from January 2004 to June 2004. Patient demographics, intraoperative finding, and postoperative results were reviewed. During the first study period, ultrasound was used in 29% of 189 laparoscopic cholecystectomies. During 2004, ultrasound was used in 77% of 66 laparoscopic cholecystectomies. Throughout both periods, fluoroscopy was only used during 6 laparoscopic common bile duct explorations (2.4% of all cases). There were no false-positive or -negative ultrasounds, and there were no bile duct injuries. As experience with ultrasound cholangiography increases, there is little indication for fluoroscopic cholangiography except for rare questions concerning anatomy and during therapeutic maneuvers for common bile duct stones.

Randomized comparison of the magnetic navigation system vs. standard wires in the treatment of bifurcations.

PubMed

Ramcharitar, Steve; van der Giessen, Willem J; van der Ent, Martin; Serruys, Patrick W; van Geuns, Robert Jan

2011-06-01

Aims Randomly compare the magnetic navigation system (MNS) to standard guidewire techniques in managing bifurcating lesions. Methods and results Thirty-one consecutive patients with bifurcating lesions were randomized to cross the bifurcating vessels prior to treatment and thereafter the struts of deployed stents with either magnetic or standard guidewires. Crossing success, crossing/fluoroscopy times, and contrast media usage were directly compared. Similar times were noted in both the magnetic wire crossings (median, IQR; 68 s, 45-138 s vs. 59 s, 32-133 s) and fluoroscopic times (median, IQR; 62 s, 44-135 s vs. 55 s, 27-133 s) when compared with standard conventional wires passage through the deployed struts. The MNS successful crossings were 30/31 (96.8%) compared with 28/31 (90.0%) observed with the standard wires. Two previously failed standard wire cases were successfully crossed with magnetic guidewires. Conclusion In contemporary stented bifurcations, the MNS achieved equivalent crossing/fluoroscopy times through deployed stents struts and may be useful in salvaging failed standard wire cases.

[Unidirectional versus multidirectional palmar locking osteosynthesis of unstable distal radius fractures: comparative analysis with LDR 2.4 mm versus 2.7 mm matrix-Smartlock].

PubMed

Hakimi, M; Jungbluth, P; Gehrmann, S; Nowak, J; Windolf, J; Wild, M

2010-03-01

Due to advances in the development of the unidirectional locking plates there is now an increased use of multidirectional palmar locking plates in the treatment of distal radius factures. The purpose of this study was to evaluate a possible improvement of the treatment and results. This prospective cohort study investigated 40 patients with C1 and C2 Colles' fractures who had been treated with unidirectional and multidirectional locking plates. The average time for the follow-up examinations was 12.3 months (range 12-15 months) after surgery. The intra-operative functional (neutral-zero method), radiological and subjective (DASH score, VAS) results were evaluated. The intra-operative fluoroscopy time of the unidirectional group was 58 s shorter compared to the multidirectional group. All fractures healed without any complication. The radiological, subjective (DASH score) and objective results for both groups were good and showed no differences. Unidirectional palmar locking plates are equally suited for the therapy of C1 and C2 fractures as multidirectional palmar locking plates but multidirectional plates require a longer fluoroscopy time.

Effectiveness of the implementation of a simple radiation reduction protocol in the catheterization laboratory.

PubMed

Jurado-Román, Alfonso; Sánchez-Pérez, Ignacio; Lozano Ruíz-Poveda, Fernando; López-Lluva, María T; Pinilla-Echeverri, Natalia; Moreno Arciniegas, Andrea; Agudo-Quilez, Pilar; Gil Agudo, Antonio

2016-01-01

A reduction in radiation doses at the catheterization laboratory, maintaining the quality of procedures is essential. Our objective was to analyze the results of a simple radiation reduction protocol at a high-volume interventional cardiology unit. We analyzed 1160 consecutive procedures: 580 performed before the implementation of the protocol and 580 after it. The protocol consisted in: the reduction of the number of ventriculographies and aortographies, the optimization of the collimation and the geometry of the X ray tube-patient-receptor, the use of low dose-rate fluoroscopy and the reduction of the number of cine sequences using the software "last fluoroscopy hold". There were no significant differences in clinical baseline features or in the procedural characteristics with the exception of a higher percentage of radial approach (30.7% vs 69.6%; p<0.001) and of percutaneous coronary interventions of chronic total occlusions after the implementation of the protocol (2.1% vs 6.7%; p=0,001). Angiographic success was similar during both periods (98.3% vs 99.2%; p=0.2). There were no significant differences between both periods regarding the overall duration of the procedures (26.9 vs 29.6min; p=0.14), or the fluoroscopy time (13.3 vs 13.2min; p=0.8). We observed a reduction in the percentage of procedures with ventriculography (80.9% vs 7.1%; p<0.0001) or aortography (15.4% vs 4.4%; p<0.0001), the cine runs (21.8 vs 6.9; p<0.0001) and the dose-area product (165 vs 71 Gyxcm(2); p<0.0001). With the implementation of a simple radiation reduction protocol, a 57% reduction of dose-area product was observed without a reduction in the quality or the complexity of procedures. Copyright © 2016 Elsevier Inc. All rights reserved.

A Novel Inherently Radiopaque Bead for Transarterial Embolization to Treat Liver Cancer - A Pre-clinical Study.

PubMed

Duran, Rafael; Sharma, Karun; Dreher, Matthew R; Ashrafi, Koorosh; Mirpour, Sahar; Lin, MingDe; Schernthaner, Ruediger E; Schlachter, Todd R; Tacher, Vania; Lewis, Andrew L; Willis, Sean; den Hartog, Mark; Radaelli, Alessandro; Negussie, Ayele H; Wood, Bradford J; Geschwind, Jean-François H

2016-01-01

Embolotherapy using microshperes is currently performed with soluble contrast to aid in visualization. However, administered payload visibility dimishes soon after delivery due to soluble contrast washout, leaving the radiolucent bead's location unknown. The objective of our study was to characterize inherently radiopaque beads (RO Beads) in terms of physicomechanical properties, deliverability and imaging visibility in a rabbit VX2 liver tumor model. RO Beads, which are based on LC Bead® platform, were compared to LC Bead. Bead size (light microscopy), equilibrium water content (EWC), density, X-ray attenuation and iodine distribution (micro-CT), suspension (settling times), deliverability and in vitro penetration were investigated. Fifteen rabbits were embolized with either LC Bead or RO Beads + soluble contrast (iodixanol-320), or RO Beads+dextrose. Appearance was evaluated with fluoroscopy, X-ray single shot, cone-beam CT (CBCT). Both bead types had a similar size distribution. RO Beads had lower EWC (60-72%) and higher density (1.21-1.36 g/cc) with a homogeneous iodine distribution within the bead's interior. RO Beads suspension time was shorter than LC Bead, with durable suspension (>5 min) in 100% iodixanol. RO Beads ≤300 µm were deliverable through a 2.3-Fr microcatheter. Both bead types showed similar penetration. Soluble contrast could identify target and non-target embolization on fluoroscopy during administration. However, the imaging appearance vanished quickly for LC Bead as contrast washed-out. RO Beads+contrast significantly increased visibility on X-ray single shot compared to LC Bead+contrast in target and non-target arteries (P=0.0043). Similarly, RO beads demonstrated better visibility on CBCT in target arteries (P=0.0238) with a trend in non-target arteries (P=0.0519). RO Beads+dextrose were not sufficiently visible to monitor embolization using fluoroscopy. RO Beads provide better conspicuity to determine target and non-target embolization compared to LC Bead which may improve intra-procedural monitoring and post-procedural evaluation of transarterial embolization.

Reduction in radiation dose for atrial fibrillation ablation over time: A 12-year single-center experience of 2344 patients.

PubMed

Voskoboinik, Aleksandr; Kalman, Elana S; Savicky, Yonatan; Sparks, Paul B; Morton, Joseph B; Lee, Geoffrey; Kistler, Peter M; Kalman, Jonathan M

2017-06-01

Pulmonary vein isolation (PVI) is a well-established treatment of atrial fibrillation (AF), with contact force (CF)-sensing catheters joining 3-dimensional mapping systems and image integration as technological advancements over the last decade. The purpose of this study was to analyze trends in radiation exposure for AF ablation over the last 12 years at our center. We reviewed prospectively collected data of 2344 consecutive PVI procedures for either paroxysmal or persistent AF between January 2004 and December 2015. During this period, all cases used 3-dimensional mapping systems, with 8 software and 2 hardware upgrades. Primary endpoints were fluoroscopy time, absorbed dose (Air Kerma in mGy), and effective dose (mSv). In total, 1914 patients underwent initial PVI, and 430 patients underwent redo PVI using radiofrequency energy. Fluoroscopy time, and absorbed and effective doses significantly and progressively decreased over the 12-year period for initial PVI as follows: 2004-2006: 61 ± 27 minutes; 2007-2009: 46 ± 14 minutes, 1365 ± 1369 mGy, 11.3 ± 12.5 mSv; 2010-2012: 31 ± 11, 464 ± 339 mGy, 9.0 ± 10.4 mSv; and 2013-2015: 17 ± 9 minutes, 304 ± 758 mGy, 5.5 ± 6.7 mSv. CF-sensing catheters were used for 357/508 PVI only cases between 2014 and 2015. Fluoroscopy times (11 ± 5 vs 21 ± 8 minutes; P <.001) and absorbed dose (200 ± 524 vs 470 ± 1326 mGy; P = .004) were significantly shorter with this catheter. Radiation exposure has dramatically decreased over the last decade for PVI and is related to operator experience, annual case volume, technology evolution, and more recently CF-sensing catheters. This has significant implications for both patient and operator long-term risk. Copyright © 2017 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Treatment of recurrent patellar dislocation via knee arthroscopy combined with C-arm fluoroscopy and reconstruction of the medial patellofemoral ligament.

PubMed

Li, Li; Wang, Hongbo; He, Yun; Si, Yu; Zhou, Hongyu; Wang, Xin

2018-06-01

Recurrent patellar dislocations were treated via knee arthroscopy combined with C-arm fluoroscopy, and reconstruction of the medial patellofemoral ligaments. Between October 2013 and March 2017, 52 cases of recurrent patellar dislocation [27 males and 25 females; age, 16-47 years (mean, 21.90 years)] were treated. Arthroscopic exploration was performed and patellofemoral joint cartilage injuries were repaired. It was subsequently determined whether it was necessary to release the lateral patellofemoral support belt. Pre-operative measurements were used to decide whether tibial tubercle osteotomy was required. Medial patellofemoral ligaments were reconstructed using autologous semitendinosus tendons. Smith and Nephew model 3.5 line anchors were used to double-anchor the medial patellofemoral margin. On the femoral side, the medial patellofemoral ligament was fixed using 7-cm, absorbable, interfacial compression screws. All cases were followed for 1-40 months (average, 21 months). The Q angle, tibial tuberosity trochlear groove distance, Insall-Salvati index, patellofemoral angle, lateral patellofemoral angle and lateral shift were evaluated on X-Ray images using the picture archiving and communication system. Subjective International Knee Documentation Committee (IKDC) knee joint functional scores and Lysholm scores were recorded. Post-operative fear was absent, and no patellar re-dislocation or re-fracture was noted during follow-up. At the end of follow-up, the patellofemoral angle (0.22±4.23°), lateral patellofemoral angle (3.44±1.30°), and lateral shift (0.36+0.14°) differed significantly from the pre-operative values (all, P<0.05). Furthermore, IKDC and Lysholm scores (87.84+3.74 and 87.48+3.35, respectively) differed significantly from the pre-operative values (both, P<0.05). These findings suggest that, in the short term, recurrent patellar dislocation treatment via knee arthroscopy combined with C-arm fluoroscopy and reconstruction of the medial patellofemoral ligament was effective.

MIS Single-position Lateral and Oblique Lateral Lumbar Interbody Fusion and Bilateral Pedicle Screw Fixation: Feasibility and Perioperative Results.

PubMed

Blizzard, Daniel J; Thomas, J Alex

2018-03-15

Retrospective review of prospectively collected data of the first 72 consecutive patients treated with single-position one- or two-level lateral (LLIF) or oblique lateral interbody fusion (OLLIF) with bilateral percutaneous pedicle screw and rod fixation by a single spine surgeon. To evaluate the clinical feasibility, accuracy, and efficiency of a single-position technique for LLIF and OLLIF with bilateral pedicle screw and rod fixation. Minimally-invasive lateral interbody approaches are performed in the lateral decubitus position. Subsequent repositioning prone for bilateral pedicle screw and rod fixation requires significant time and resources and does not facilitate increased lumbar lordosis. The first 72 consecutive patients (300 screws) treated with single-position LLIF or OLLIF and bilateral pedicle screws by a single surgeon between December 2013 and August 2016 were included in the study. Screw accuracy and fusion were graded using computed tomography and several timing parameters were recorded including retractor, fluoroscopy, and screw placement time. Complications including reoperation, infection, and postoperative radicular pain and weakness were recorded. Average screw placement time was 5.9 min/screw (standard deviation, SD: 1.5 min; range: 3-9.5 min). Average total operative time (interbody cage and pedicle screw placement) was 87.9 minutes (SD: 25.1 min; range: 49-195 min). Average fluoroscopy time was 15.0 s/screw (SD: 4.7 s; range: 6-25 s). The pedicle screw breach rate was 5.1% with 10/13 breaches measured as < 2 mm in magnitude. Fusion rate at 6-months postoperative was 87.5%. Two (2.8%) patients underwent reoperation for malpositioned pedicle screws with subsequent resolution of symptoms. The single-position, all-lateral technique was found to be feasible with accuracy, fluoroscopy usage, and complication rates comparable with the published literature. This technique eliminates the time and staffing associated with intraoperative repositioning and may lead to significant improvements in operative efficiency and cost savings. 4.

3D kinematics of mobile-bearing total knee arthroplasty using X-ray fluoroscopy.

PubMed

Yamazaki, Takaharu; Futai, Kazuma; Tomita, Tetsuya; Sato, Yoshinobu; Yoshikawa, Hideki; Tamura, Shinichi; Sugamoto, Kazuomi

2015-04-01

Total knee arthroplasty (TKA) 3D kinematic analysis requires 2D/3D image registration of X-ray fluoroscopic images and a computer-aided design (CAD) model of the knee implant. However, these techniques cannot provide information on the radiolucent polyethylene insert, since the insert silhouette does not appear clearly in X-ray images. Therefore, it is difficult to obtain the 3D kinematics of the polyethylene insert, particularly the mobile-bearing insert. A technique for 3D kinematic analysis of a mobile-bearing insert used in TKA was developed using X-ray fluoroscopy. The method was tested and a clinical application was evaluated. Tantalum beads and a CAD model of the mobile-bearing TKA insert are used for 3D pose estimation of the mobile-bearing insert used in TKA using X-ray fluoroscopy. The insert model was created using four identical tantalum beads precisely located at known positions in a polyethylene insert using a specially designed insertion device. Finally, the 3D pose of the insert model was estimated using a feature-based 2D/3D registration technique, using the silhouette of beads in fluoroscopic images and the corresponding CAD insert model. In vitro testing for the repeatability of the positioning of the tantalum beads and computer simulations for 3D pose estimation of the mobile-bearing insert were performed. The pose estimation accuracy achieved was sufficient for analyzing mobile-bearing TKA kinematics (RMS error: within 1.0 mm and 1.0°, except for medial-lateral translation). In a clinical application, nine patients with mobile-bearing TKA were investigated and analyzed with respect to a deep knee bending motion. A 3D kinematic analysis technique was developed that enables accurate quantitative evaluation of mobile-bearing TKA kinematics. This method may be useful for improving implant design and optimizing TKA surgical techniques.

Hand and body radiation exposure with the use of mini C-arm fluoroscopy.

PubMed

Tuohy, Christopher J; Weikert, Douglas R; Watson, Jeffry T; Lee, Donald H

2011-04-01

To determine whole body and hand radiation exposure to the hand surgeon wearing a lead apron during routine intraoperative use of the mini C-arm fluoroscope. Four surgeons (3 hand attending surgeons and 1 hand fellow) monitored their radiation exposure for a total of 200 consecutive cases (50 cases per surgeon) requiring mini C-arm fluoroscopy. Each surgeon measured radiation exposure with a badge dosimeter placed on the outside breast pocket of the lead apron (external whole body exposure), a second badge dosimeter under the lead apron (shielded whole body exposure), and a ring dosimeter (hand exposure). Completed records were noted in 198 cases, with an average fluoroscopy time of 133.52 seconds and average cumulative dose of 19,260 rem-cm(2) per case. The total measured radiation exposures for the (1) external whole body exposure dosimeters were 16 mrem (for shallow depth), 7 mrem (for eye depth), and less than 1 mrem (for deep depth); (2) shielded whole body badge dosimeters recorded less than 1 mrem; and (3) ring dosimeters totaled 170 mrem. The total radial exposure for 4 ring dosimeters that had registered a threshold of 30 mrem or more of radiation exposure was 170 mrem at the skin level, for an average of 42.5 mrem per dosimeter ring or 6.3 mrem per case. This study of whole body and hand radiation exposure from the mini C-arm includes the largest number of surgical cases in the published literature. The measured whole body and hand radiation exposure received by the hand surgeon from the mini C-arm represents a minimal risk of radiation, based on the current National Council on Radiation Protection and Management standards of annual dose limits (5,000 mrem per year for whole body and 50,000 mrem per year to the extremities). Copyright © 2011 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

The Corona Dentis: Description of an Anatomic Variant with Technical Implications for Anterior Odontoid Screw Placement.

PubMed

Alonso, Fernando; Iwanaga, Joe; Chapman, Jens R; Oskouian, Rod J; Tubbs, R Shane

2017-08-01

Type 2 odontoid fractures are the most common cervical fractures among the elderly. Neurologic deficit is usually caused by myelopathy as a result of posterior dens migration. Direct anterior screw placement provides stabilization and can preserve C1-C2 movement. The presence of a bony excrescence on the anterior superior tip of the dens may lead to placement of a screw of incorrect length. Twenty C2 dry specimens were examined for the presence of a corona dentis, which is a bony excrescence in the coronal plane near the apex of the dens. When identified, measurements of the corona dentis were performed using calipers and a ruler. In addition, anteroposterior (AP) and lateral fluoroscopy was performed on all specimens found to have a corona dentis. A corona dentis was found on 20% of our C2 specimens and had an average width of 9 mm and an average height of 4.5 mm. The average width of the dens did not vary as the normal tip of the dens transitioned into the coronae. In no specimen did the corona dentis seem to be composed of trabecular bone and it was seen as a superior projection of cortical bone on fluoroscopy. On fluoroscopy, the corona dentis could be identified on a true AP projection. In angulated AP views, fluoroscopic images overestimated the length of the corona dentis. We describe a new entity termed the corona dentis because of its crownlike feature. It is a superior cortical bone protrusion and should be noted as a variant of the dens during anterior odontoid screw placement. Its propensity to increase the height of the dens markedly can lead to higher rates of neurologic deficits during type 2 odontoid fractures if not appreciated. A true AP view is critical for correct screw size placement. Copyright © 2017 Elsevier Inc. All rights reserved.

Image Registration of Cone-Beam Computer Tomography and Preprocedural Computer Tomography Aids in Localization of Adrenal Veins and Decreasing Radiation Dose in Adrenal Vein Sampling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Busser, Wendy M. H., E-mail: wendy.busser@radboudumc.nl; Arntz, Mark J.; Jenniskens, Sjoerd F. M.

2015-08-15

PurposeWe assessed whether image registration of cone-beam computed tomography (CT) (CBCT) and contrast-enhanced CT (CE-CT) images indicating the locations of the adrenal veins can aid in increasing the success rate of first-attempts adrenal vein sampling (AVS) and therefore decreasing patient radiation dose.Materials and Methods CBCT scans were acquired in the interventional suite (Philips Allura Xper FD20) and rigidly registered to the vertebra in previously acquired CE-CT. Adrenal vein locations were marked on the CT image and superimposed with live fluoroscopy and digital-subtraction angiography (DSA) to guide the AVS. Seventeen first attempts at AVS were performed with image registration and retrospectivelymore » compared with 15 first attempts without image registration performed earlier by the same 2 interventional radiologists. First-attempt AVS was considered successful when both adrenal vein samples showed representative cortisol levels. Sampling time, dose-area product (DAP), number of DSA runs, fluoroscopy time, and skin dose were recorded.ResultsWithout image registration, the first attempt at sampling was successful in 8 of 15 procedures indicating a success rate of 53.3 %. This increased to 76.5 % (13 of 17) by adding CBCT and CE-CT image registration to AVS procedures (p = 0.266). DAP values (p = 0.001) and DSA runs (p = 0.026) decreased significantly by adding image registration guidance. Sampling and fluoroscopy times and skin dose showed no significant changes.ConclusionGuidance based on registration of CBCT and previously acquired diagnostic CE-CT can aid in enhancing localization of the adrenal veins thereby increasing the success rate of first-attempt AVS with a significant decrease in the number of used DSA runs and, consequently, radiation dose required.« less

Optimizing radiofrequency ablation of paroxysmal and persistent atrial fibrillation by direct catheter force measurement-a case-matched comparison in 198 patients.

PubMed

Sigmund, Elisabeth; Puererfellner, Helmut; Derndorfer, Michael; Kollias, Georgios; Winter, Siegmund; Aichinger, Josef; Nesser, Hans-Joachim; Martinek, Martin

2015-02-01

Sufficient electrode-tissue contact is crucial for adequate lesion formation in radiofrequency catheter ablation (RFCA). We assessed the impact of direct catheter force measurement on acute procedural parameters and outcome of RFCA for paroxysmal and persistent atrial fibrillation (AF). Ninety-nine consecutive patients (70% men) with paroxysmal (63.6%) or persistent AF underwent left atrial RFCA using a 3.5-mm open-irrigated-tip (OIT) catheter with contact force measurement capabilities (group 1). For comparison a case-matched cohort with standard OIT catheters was used (99 patients; group 2). Case matching included gender, type of AF, number or RFCA procedures, and type of procedure. Procedural data showed a significant decline in radiofrequency ablation time from 52 ± 20 to 44 ± 16 minutes (P = 0.003) with a remarkable mean reduction in overall procedure time of 34 minutes (P = 0.0001; 225.8 ± 53.1 vs 191.9 ± 53.3 minutes). In parallel, the total fluoroscopy time could be significantly reduced from 28.5 ± 11.0 to 19.9 ± 9.3 minutes (P = 0.0001) as well as fluoroscopy dose from 74.1 ± 58.0 to 56.7 ± 38.9 Gy/cm(2) (P = 0.016). Periprocedural complications were similar in both groups. The use of contact force sensing technology is able to significantly reduce ablation, procedure, and fluoroscopy times as well as dose in RFCA of AF in a mixed case-matched group of paroxysmal and persistent AF. Energy delivery is substantially reduced by avoiding radiofrequency ablation in positions with insufficient surface contact. Additionally 12-month outcome data showed increased efficacy. Such time saving and equally safe technology may have a relevant impact on laboratory management and increased cost effectiveness. © 2014 Wiley Periodicals, Inc.

SU-E-I-58: Experiences in Setting Up An Online Fluoroscopy Tracking System in a Large Healthcare System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fisher, R; Wunderle, K; Lingenfelter, M

Purpose: Transitioning from a paper based to an online system for tracking fluoroscopic case information required by state regulation and to conform to NCRP patient dose tracking suggestions. Methods: State regulations require documentation of operator, equipment, and some metric of tube output for fluoroscopy exams. This information was previously collected in paper logs, which was cumbersome and inefficient for the large number of fluoroscopic units across multiple locations within the system. The “tech notes” feature within Siemens’ Syngo workflow RIS was utilized to create an entry form for technologists to input case information, which was sent to a third partymore » vendor for archiving and display though an online web based portal. Results: Over 55k cases were logged in the first year of implementation, with approximately 6,500 cases per month once fully online. A system was built for area managers to oversee and correct data, which has increased the accuracy of inputted values. A high-dose report was built to automatically send notifications when patients exceed trigger levels. In addition to meeting regulatory requirements, the new system allows for larger scale QC in fluoroscopic cases by allowing comparison of data from specific procedures, locations, equipment, and operators so that instances that fall outside of reference levels can be identified for further evaluation. The system has also drastically improved identification of operators without documented equipment specific training. Conclusion: The transition to online fluoroscopy logs has improved efficiency in meeting state regulatory requirements as well as allowed for identification of particular procedures, equipment, and operators in need of additional attention in order to optimize patient and personnel doses, while high dose alerts improve patient care and follow up. Future efforts are focused on incorporating case information from outside of radiology, as well as on automating processes for increased efficiencies.« less

SU-E-P-01: An Informative Review On the Role of Diagnostic Medical Physicist in the Academic and Private Medical Centers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weir, V; Zhang, J

Purpose: The role of physicist in the academic and private hospital environment continues to evolve and expand. This becomes more obvious with the newly revised requirements of the Joint Commission (JC) on imaging modalities and the continued updated requirements of ACR accreditation for medical physics (i.e., starting in June 2014, a physicists test will be needed before US accreditation). We provide an informative review on the role of diagnostic medical physicist and hope that our experience will expedite junior physicists in understanding their role in medical centers, and be ready to more opportunities. Methods: Based on our experience, diagnostic medicalmore » physicists in both academic and private medical centers perform several clinical functions. These include providing clinical service and physics support, ensuring that all ionizing radiation devices are tested and operated in compliance with the State and Federal laws, regulations and guidelines. We also discuss the training and education required to ensure that the radiation exposure to patients and staff is as low as reasonably achievable. We review the overlapping roles of medical and health physicist in some institutions. Results: A detailed scheme on the new requirements (effective 7/1/2014) of the JC is provided. In 2015, new standards for fluoroscopy, cone beam CT and the qualifications of staff will be phased in. A summary of new ACR requirements for different modalities is presented. Medical physicist have other duties such as sitting on CT and fluoroscopy committees for protocols design, training of non-radiologists to meet the new fluoroscopy rules, as well as helping with special therapies such as Yittrium 90 cases. Conclusion: Medical physicists in both academic and private hospitals are positioned to be more involved and prominent. Diagnostic physicists need to be more proactive to involve themselves in the day to day activities of the radiology department.« less

Planning, guidance, and quality assurance of pelvic screw placement using deformable image registration

NASA Astrophysics Data System (ADS)

Goerres, J.; Uneri, A.; Jacobson, M.; Ramsay, B.; De Silva, T.; Ketcha, M.; Han, R.; Manbachi, A.; Vogt, S.; Kleinszig, G.; Wolinsky, J.-P.; Osgood, G.; Siewerdsen, J. H.

2017-12-01

Percutaneous pelvic screw placement is challenging due to narrow bone corridors surrounded by vulnerable structures and difficult visual interpretation of complex anatomical shapes in 2D x-ray projection images. To address these challenges, a system for planning, guidance, and quality assurance (QA) is presented, providing functionality analogous to surgical navigation, but based on robust 3D-2D image registration techniques using fluoroscopy images already acquired in routine workflow. Two novel aspects of the system are investigated: automatic planning of pelvic screw trajectories and the ability to account for deformation of surgical devices (K-wire deflection). Atlas-based registration is used to calculate a patient-specific plan of screw trajectories in preoperative CT. 3D-2D registration aligns the patient to CT within the projective geometry of intraoperative fluoroscopy. Deformable known-component registration (dKC-Reg) localizes the surgical device, and the combination of plan and device location is used to provide guidance and QA. A leave-one-out analysis evaluated the accuracy of automatic planning, and a cadaver experiment compared the accuracy of dKC-Reg to rigid approaches (e.g. optical tracking). Surgical plans conformed within the bone cortex by 3-4 mm for the narrowest corridor (superior pubic ramus) and  >5 mm for the widest corridor (tear drop). The dKC-Reg algorithm localized the K-wire tip within 1.1 mm and 1.4° and was consistently more accurate than rigid-body tracking (errors up to 9 mm). The system was shown to automatically compute reliable screw trajectories and accurately localize deformed surgical devices (K-wires). Such capability could improve guidance and QA in orthopaedic surgery, where workflow is impeded by manual planning, conventional tool trackers add complexity and cost, rigid tool assumptions are often inaccurate, and qualitative interpretation of complex anatomy from 2D projections is prone to trial-and-error with extended fluoroscopy time.

Surgical Navigation Technology Based on Augmented Reality and Integrated 3D Intraoperative Imaging

PubMed Central

Elmi-Terander, Adrian; Skulason, Halldor; Söderman, Michael; Racadio, John; Homan, Robert; Babic, Drazenko; van der Vaart, Nijs; Nachabe, Rami

2016-01-01

Study Design. A cadaveric laboratory study. Objective. The aim of this study was to assess the feasibility and accuracy of thoracic pedicle screw placement using augmented reality surgical navigation (ARSN). Summary of Background Data. Recent advances in spinal navigation have shown improved accuracy in lumbosacral pedicle screw placement but limited benefits in the thoracic spine. 3D intraoperative imaging and instrument navigation may allow improved accuracy in pedicle screw placement, without the use of x-ray fluoroscopy, and thus opens the route to image-guided minimally invasive therapy in the thoracic spine. Methods. ARSN encompasses a surgical table, a motorized flat detector C-arm with intraoperative 2D/3D capabilities, integrated optical cameras for augmented reality navigation, and noninvasive patient motion tracking. Two neurosurgeons placed 94 pedicle screws in the thoracic spine of four cadavers using ARSN on one side of the spine (47 screws) and free-hand technique on the contralateral side. X-ray fluoroscopy was not used for either technique. Four independent reviewers assessed the postoperative scans, using the Gertzbein grading. Morphometric measurements of the pedicles axial and sagittal widths and angles, as well as the vertebrae axial and sagittal rotations were performed to identify risk factors for breaches. Results. ARSN was feasible and superior to free-hand technique with respect to overall accuracy (85% vs. 64%, P < 0.05), specifically significant increases of perfectly placed screws (51% vs. 30%, P < 0.05) and reductions in breaches beyond 4 mm (2% vs. 25%, P < 0.05). All morphometric dimensions, except for vertebral body axial rotation, were risk factors for larger breaches when performed with the free-hand method. Conclusion. ARSN without fluoroscopy was feasible and demonstrated higher accuracy than free-hand technique for thoracic pedicle screw placement. Level of Evidence: N/A PMID:27513166

Surgical Management After Hysteroscopic Sterilization: Minimally Invasive Approach Incorporating Intraoperative Fluoroscopy for Symptomatic Patients with >2 Essure® Devices.

PubMed

Sills, E Scott; Rickers, Natalie S; Li, Xiang

2018-06-01

To describe a non-hysterectomy surgical technique for symptomatic patients with >2 Essure® (Bayer Healthcare, Whippany, New Jersey) devices. Patients (n=4) presented with sharp pelvic pain, irregular vaginal bleeding, dyspareunia, weight gain, hair loss, fatigue, and/or diffuse skin rash, all of which were absent before undergoing hysteroscopic sterilization (HS). Hysterosalpingogram obtained before surgical excision of contraceptive tubal implants confirmed more than two Essure® devices in all patients. Except for HS-associated complaints, all patients were in otherwise good general health and none had any history of prior pelvic pathology. Hysteroscopy was followed by 5mm triple-port laparoscopic cornual dissection, modified partial bilateral salpingectomy, and foreign body removal under fluoroscopy and/or radiographic guidance. In this group, mean±SD patient age was 41±8yrs and interval between HS and device removal was 6.4±2.7yrs. At the conclusion of each case (mean±SD operative time=179±11min), imaging studies were reviewed by an attending radiologist and verified no retained metal in the abdomen. Conversion to laparotomy, hysterectomy, or blood transfusion was unnecessary for any patients, and all were discharged home within three hours. Their postoperative course continues to be satisfactory. Patients with more than two Essure® devices comprise an unusual group with a complex pelvic foreign body presentation. This is the first report on surgical management for such patients, underscoring the importance of localizing these contraceptive devices with careful imaging before, during, and after surgery. Moreover, hysterectomy is not absolutely mandatory in this setting and intraoperative fluoroscopy/radiography can facilitate complete, safe removal of all implants on an out-patient basis. Creation of ICD-10 modifiers for various post-HS complaints would allow for improved surveillance of the Essure® phenomenon.

Yttrium-90 Resin Microsphere Radioembolization Using an Antireflux Catheter: An Alternative to Traditional Coil Embolization for Nontarget Protection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morshedi, Maud M., E-mail: maud.morshedi@my.rfums.org; Bauman, Michael, E-mail: mbauman@ucsd.edu; Rose, Steven C., E-mail: scrose@ucsd.edu

2015-04-15

PurposeSerious complications can result from nontarget embolization during yttrium-90 (Y-90) transarterial radioembolization. Hepatoenteric artery coil embolization has been traditionally performed to prevent nontarget radioembolization. The U.S. Food and Drug Administration–approved Surefire Infusion System (SIS) catheter, designed to prevent reflux, is an alternative to coils. The hypothesis that quantifiable SIS procedural parameters are comparable to coil embolization was tested.MethodsFourteen patients aged 36–79 years with colorectal, neuroendocrine, hepatocellular, and other predominantly bilobar hepatic tumors who underwent resin microsphere Y-90 radioembolization using only the SIS catheter (n = 7) versus only detachable coils (n = 7) for nontarget protection were reviewed retrospectively. Procedure time, fluoroscopy time, contrast dose,more » radiation dose, and cost were evaluated.ResultsMultivariate analysis identified significant cohort differences in the procedural parameters evaluated (F(10, 3) = 10.39, p = 0.04). Between-group comparisons of the pretreatment planning procedure in the SIS catheter group compared to the coil embolization group demonstrated a significant reduction in procedure time (102.6 vs. 192.1 min, respectively, p = 0.0004), fluoroscopy time (14.3 vs. 49.7 min, respectively, p = 0.0016), and contrast material dose (mean dose of 174.3 vs. 265.0 mL, respectively, p = 0.0098). Procedural parameters were not significantly different between the two groups during subsequent dose delivery procedures. Overall cost of combined first-time radioembolization procedures was significantly less in the SIS group ($4252) compared to retrievable coil embolization ($11,123; p = 0.001).ConclusionThe SIS catheter results in a reduction in procedure time, fluoroscopy time, and contrast material dose and may be an attractive cost-effective alternative to detachable coil embolization for prevention of nontarget radioembolization.« less

Characterization of MOSFET Dosimeter Angular Response Using a Spherical Phantom for Fluoroscopic Dosimetry.

PubMed

Wang, Chu; Hill, Kevin; Yoshizumi, Terry

2016-01-01

Metal-Oxide Semiconductor Field-Effect Transistor (MOSFET) dosimeters, placed in anthropomorphic phantoms, are a standard method for organ dosimetry in medical x-ray imaging applications. However, many x-ray applications, particularly fluoroscopy procedures, use variable projection angles. During dosimetry, the MOSFET detector active area may not always be perpendicular to the x-ray beam. The goal of this study was to characterize the dosimeter's angular response in the fluoroscopic irradiation involved in pediatric cardiac catheterization procedures, during which a considerable amount of fluoroscopic x-ray irradiation is often applied from various projection angles. A biological x-ray irradiator was used to simulate the beam quality of a biplane fluoroscopy imaging system. A custom-designed acrylic spherical scatter phantom was fabricated to measure dosimeter response (in mV) in two rotational axes, axial (ψ) and normal-to-axial (θ), in 30° increments, as well as four common oblique angles used in cardiac catheterization: a) 90° Left Anterior Oblique (LAO); b) 70° LAO/ 20° Cranial; c) 20° LAO/ 15° Cranial; and d) 30° Right Anterior Oblique (RAO). All results were normalized to the angle where the dosimeter epoxy is perpendicular to the beam or the Posterior-Anterior projection angle in the clinical setup. The relative response in the axial rotation was isotropic (within ± 10% deviation); that in the normal-to-axial rotation was isotropic in all angles except the ψ = 270° angle, where the relative response was 83 ± 9%. No significant deviation in detector response was observed in the four common oblique angles, with their relative responses being: a) 102 ± 3%; b) 90 ± 3%; c) 92 ± 3%; and d) 95 ± 3%, respectively. These angular correction factors will be used in future dosimetry studies for fluoroscopy. The spherical phantom may be useful for other applications, as it allows the measurement of dosimeter response in virtually all angles in the 3-dimensional spherical coordinates.

Flexible Ureterorenoscopy versus Mini-Percutaneous Nephrolithotomy for the Treatment of Renal Stones.

PubMed

Ergin, Giray; Kirac, Mustafa; Kopru, Burak; Ebiloglu, Turgay; Biri, Hasan

2018-04-22

To compare the pain status and stone free rates of flexible ureterorenoscopy (F-URS) versus mini-percutaneousnephrolithotomy (mini-PNL) for the treatment of 1-to 2-cm renal stones. This study was retrospectively designed with match paired method. Between January 2013 and December 2016, 387 patients underwent stone surgery for renal stones, 45 patients underwent FURS and 45 patients underwent mini-PNL. 90 patients were divided into two groups according to the surgical procedures. Group 1 patients underwent F-URS, and Group 2 patients underwent mini-PNL. During the intraoperative andpostoperative periods, pain management for all patients was standardized. Pain scores were determined using a visual analogue scale (VAS) completed at 2, 6, 12 and 24 hours postoperatively. The stone free status, hemoglobin levels, fluoroscopy time (FT), operation time (OT), hospitalization time (HT), return to work time (RWT), and complications were noted for each patient. Of all patients, the mean age was 41.1 ± 12.1 years and the mean stone size was 13.9 ± 2.9 mm. The VAS scores were significantly higher in the mini-PNL group at 2, 6, 12 and 24 hours (P < .05). The stone-free status and complication rates were similar between the two groups (P > .05); however, the hemoglobin decreases and the fluoroscopy, operation, hospitalization and return to work times were higher in the mini-PNL group than in the F-URS group (P < .05). F-URS is less painful than mini-PNL for the treatment of 1- to 2-cm renal stones. However, the stone free rate is similar between the two procedures while mini-PNL is superior in terms of fluoroscopy, operation, hospitalization and return to work duration. We think that F-URS is more comfortable and less painful than mini-PNL and achieves a similar stone free rate for the treatment of 1- to 2-cm renal stones.

Puncture Reduction in Percutaneous Transforaminal Endoscopic Discectomy with HE's Lumbar LOcation (HELLO) System: A Cadaver Study.

PubMed

Fan, Guoxin; Guan, Xiaofei; Sun, Qi; Hu, Annan; Zhu, Yanjie; Gu, Guangfei; Zhang, Hailong; He, Shisheng

2015-01-01

Percutaneous transforaminal endoscopic discectomy (PTED) usually requires numerous punctures under X-ray fluoroscopy. Repeated puncture will lead to more radiation exposure and reduce the beginners' confidence. This cadaver study aimed to investigate the efficacy of HE's Lumbar Location (HELLO) system in puncture reduction of PTED. Cadaver study. Comparative groups. HELLO system consists of self-made surface locator and puncture locator. One senior surgeon conducted the puncture procedure of PTED on the left side of 20 cadavers at L4/L5 and L5/S1 level with the assistance of HELLO system (Group A). Additionally, the senior surgeon conducted the puncture procedure of PTED on the right side of the cadavers at L4/L5 and L5/S1 level with traditional methods (Group B). On the other hand, an inexperienced surgeon conducted the puncture procedure of PTED on the left side of the cadavers at L4/L5 and L5/S1 level with the assistance of our HELLO system (Group C). At L4/L5 level, there was significant difference in puncture times between Group A and Group B (P<0.001), but no significant difference was observed between Group A and Group C (P = 0.811). Similarly at L5/S1 level, there was significant difference in puncture times between Group A and Group B (P<0.001), but no significant difference was observed between Group A and Group C (P = 0.981). At L4/L5 level, there was significant difference in fluoroscopy time between Group A and Group B (P<0.001), but no significant difference was observed between Group A and Group C (P = 0.290). Similarly at L5/S1 level, there was significant difference in fluoroscopy time between Group A and Group B (P<0.001), but no significant difference was observed between Group A and Group C (P = 0.523). As for radiation exposure, HELLO system reduced 39%-45% radiation dosage when comparing Group A and Group B, but there was no significant difference in radiation exposure between Group A and Group C whatever at L4/L5 level or L5/S1 level (P>0.05). There was no difference in location time between Group A and Group B or Group A and Group C either at L4/L5 level or L5/S1 level (P>0.05). Small-sample preclinical study. HELLO system was effective in reducing puncture times, fluoroscopy time and radiation exposure, as well as the difficulty of learning PTED. (2015-RES-127).

Patient and surgeon radiation exposure during spinal instrumentation using intraoperative computed tomography-based navigation.

PubMed

Mendelsohn, Daniel; Strelzow, Jason; Dea, Nicolas; Ford, Nancy L; Batke, Juliet; Pennington, Andrew; Yang, Kaiyun; Ailon, Tamir; Boyd, Michael; Dvorak, Marcel; Kwon, Brian; Paquette, Scott; Fisher, Charles; Street, John

2016-03-01

Imaging modalities used to visualize spinal anatomy intraoperatively include X-ray studies, fluoroscopy, and computed tomography (CT). All of these emit ionizing radiation. Radiation emitted to the patient and the surgical team when performing surgeries using intraoperative CT-based spine navigation was compared. This is a retrospective cohort case-control study. Seventy-three patients underwent CT-navigated spinal instrumentation and 73 matched controls underwent spinal instrumentation with conventional fluoroscopy. Effective doses of radiation to the patient when the surgical team was inside and outside of the room were analyzed. The number of postoperative imaging investigations between navigated and non-navigated cases was compared. Intraoperative X-ray imaging, fluoroscopy, and CT dosages were recorded and standardized to effective doses. The number of postoperative imaging investigations was compared with the matched cohort of surgical cases. A literature review identified historical radiation exposure values for fluoroscopic-guided spinal instrumentation. The 73 navigated operations involved an average of 5.44 levels of instrumentation. Thoracic and lumbar instrumentations had higher radiation emission from all modalities (CT, X-ray imaging, and fluoroscopy) compared with cervical cases (6.93 millisievert [mSv] vs. 2.34 mSv). Major deformity and degenerative cases involved more radiation emission than trauma or oncology cases (7.05 mSv vs. 4.20 mSv). On average, the total radiation dose to the patient was 8.7 times more than the radiation emitted when the surgical team was inside the operating room. Total radiation exposure to the patient was 2.77 times the values reported in the literature for thoracolumbar instrumentations performed without navigation. In comparison, the radiation emitted to the patient when the surgical team was inside the operating room was 2.50 lower than non-navigated thoracolumbar instrumentations. The average total radiation exposure to the patient was 5.69 mSv, a value less than a single routine lumbar CT scan (7.5 mSv). The average radiation exposure to the patient in the present study was approximately one quarter the recommended annual occupational radiation exposure. Navigation did not reduce the number of postoperative X-rays or CT scans obtained. Intraoperative CT navigation increases the radiation exposure to the patient and reduces the radiation exposure to the surgeon when compared with values reported in the literature. Intraoperative CT navigation improves the accuracy of spine instrumentation with acceptable patient radiation exposure and reduced surgical team exposure. Surgeons should be aware of the implications of radiation exposure to both the patient and the surgical team when using intraoperative CT navigation. Copyright © 2016 Elsevier Inc. All rights reserved.

Prospective Evaluation of the Correlation Between Torso Height and Aortic Anatomy in Respect of a Fluoroscopy Free Aortic Balloon Occlusion System

DTIC Science & Technology

2014-06-01

austere circumstances, providing a physiologic bridge to definitive hemorrhage control. The clinical use of this technique was first described in the...Support Hospital in Camp Bastion , Helmand Province, Southern Afghanistan. This hospital is unique in the theater of Afghanistan as it is a joint UK–US

Superior herniation of the mediastinum presenting as an anterior neck mass on straining.

PubMed

McDougall, Catherine M; Culham, Gordon; Seear, Michael D; Chilvers, Mark A

2012-07-01

We report an infant with an anterior neck mass present only on straining. Airway fluoroscopy revealed this to be due to superior mediastinal herniation. Neck masses apparent only during Valsalva maneuver are rare and awareness of the differential diagnosis is important to avoid unnecessary investigation or surgery. Copyright © 2012 Wiley Periodicals, Inc.

Simulation Training in Health Care

DTIC Science & Technology

2015-06-01

Harvey simulates cardiac and lung disease , including blood pressure, breathing, pulses, heart sounds, and murmurs. A significant step toward the...fluoroscopy, cardiovascu- lar and pulmonary disease diagnosis and treatment, anesthesia, patient -centered programs, basic vital signs emergency care, infant...effectiveness. However, in health care, ethical considerations and the quantification of the expenses of clinician “learning” on patients is a challenge to

The modern treatment of oesophageal strictures using the Eder-Puestow dilators.

PubMed

Borgeskov, S; Struve-Christensen, E

1978-01-01

The greatest safety in bouginage of narrow and twisted oesophageal strictures is obtained by employing a flexible oesophagoscope via which a guiding probe is introduced by Puestow's method. The actual bougie may then be introduced over this guide without risk of perforating the oesophagus. When performed under TV-fluoroscopy, this procedure gains added safety. 108 dilations were performed without complications.

Selecting appropriate gastroenteric contrast media for diagnostic fluoroscopic imaging in infants and children: a practical approach.

PubMed

Callahan, Michael J; Talmadge, Jennifer M; MacDougall, Robert D; Kleinman, Patricia L; Taylor, George A; Buonomo, Carlo

2017-04-01

In our experience, questions about the appropriate use of enteric contrast media for pediatric fluoroscopic studies are common. The purpose of this article is to provide a comprehensive review of enteric contrast media used for pediatric fluoroscopy, highlighting the routine use of these media at a large tertiary care pediatric teaching hospital.

[Non-biological 3D printed simulator for training in percutaneous nephro- lithotripsy].

PubMed

Alyaev, Yu G; Sirota, E S; Bezrukov, E A; Ali, S Kh; Bukatov, M D; Letunovskiy, A V; Byadretdinov, I Sh

2018-03-01

To develop a non-biological 3D printed simulator for training and preoperative planning in percutaneous nephrolithotripsy (PCNL), which allows doctors to master and perform all stages of the operation under ultrasound and fluoroscopy guidance. The 3D model was constructed using multislice spiral computed tomography (MSCT) images of a patient with staghorn urolithiasis. The MSCT data were processed and used to print the model. The simulator consisted of two parts: a non-biological 3D printed soft model of a kidney with reproduced intra-renal vascular and collecting systems and a printed 3D model of a human body. Using this 3D printed simulator, PCNL was performed in the interventional radiology operating room under ultrasound and fluoroscopy guidance. The designed 3D printed model of the kidney completely reproduces the individual features of the intra-renal structures of the particular patient. During the training, all the main stages of PCNL were performed successfully: the puncture, dilation of the nephrostomy tract, endoscopic examination, intra-renal lithotripsy. Our proprietary 3D-printed simulator is a promising development in the field of endourologic training and preoperative planning in the treatment of complicated forms of urolithiasis.

Measurement of intervertebral motion using quantitative fluoroscopy: report of an international forum and proposal for use in the assessment of degenerative disc disease in the lumbar spine.

PubMed

Breen, Alan C; Teyhen, Deydre S; Mellor, Fiona E; Breen, Alexander C; Wong, Kris W N; Deitz, Adam

2012-01-01

Quantitative fluoroscopy (QF) is an emerging technology for measuring intervertebral motion patterns to investigate problem back pain and degenerative disc disease. This International Forum was a networking event of three research groups (UK, US, Hong Kong), over three days in San Francisco in August 2009. Its aim was to reach a consensus on how best to record, analyse, and communicate QF information for research and clinical purposes. The Forum recommended that images should be acquired during regular trunk motion that is controlled for velocity and range, in order to minimise externally imposed variability as well as to correlate intervertebral motion with trunk motion. This should be done in both the recumbent passive and weight bearing active patient configurations. The main recommended outputs from QF were the true ranges of intervertebral rotation and translation, neutral zone laxity and the consistency of shape of the motion patterns. The main clinical research priority should initially be to investigate the possibility of mechanical subgroups of patients with chronic, nonspecific low back pain by comparing their intervertebral motion patterns with those of matched healthy controls.

Fiber sensor assisted in-vivo needle guidance for minimally invasive procedures (Conference Presentation)

NASA Astrophysics Data System (ADS)

Baghdadchi, Saharnaz; Chao, Cherng; Esener, Sadik; Mattrey, Robert F.; Eghtedari, Mohammad A.

2017-02-01

Image-guided procedures are performed frequently by radiologists to insert a catheter within a target vessel or lumen or to perform biopsy of a lesion. For instance, an interventional radiologist uses fluoroscopy during percutaneous biliary drainage procedure (a procedure during which a catheter is inserted through the skin to drain the bile from liver) to identify the location of the needle tip within liver parenchyma, hepatic blood vessel or bile duct. However, the identification of the target organ under fluoroscopy exposes the patient to x-ray irradiation, which may be significant if the time of procedure is prolonged. We have designed a fiber core needle system that may help the radiologist identify the location of the needle tip in real time without exposing the patient to x-ray. Our needle system transmits a low power modulated light into the tissue through a fiber cable embedded in the needle and detects the backscattered light using another fiber inside the needle. We were able to successfully distinguish the location of our prototype needle tip inside a cow liver phantom to identify if the needle tip was within liver parenchyma, liver vessels, or in the bile duct based on the recorded backscattered light.

A simple method to accurately position Port-A-Cath without the aid of intraoperative fluoroscopy or other localizing devices.

PubMed

Horng, Huann-Cheng; Yuan, Chiou-Chung; Chao, Kuan-Chong; Cheng, Ming-Huei; Wang, Peng-Hui

2007-06-01

To evaluate the efficacy and acceptability of the Port-A-Cath (PAC) insertion method with (conventional group as II) and without (modified group as I) the aid of intraoperative fluoroscopy or other localizing devices. A total of 158 women with various kinds of gynecological cancers warranting PAC insertion (n = 86 in group I and n = 72 in group II, respectively) were evaluated. Data for analyses included patient age, main disease, dislocation site, surgical time, complications, and catheter outcome. There was no statistical difference between the two groups in terms of age, main disease, complications, and the experiencing of patent catheters. However, appropriate positioning (100% in group I, and 82% in group II) in the superior vena cava (SVC) showed statistical differences between the two groups (P = 0.001). In addition, the surgical time in group I was statistically shorter than that in group II (P < 0.001). The modified method for inserting the PAC offered the following benefits: including avoiding X-ray exposure for both the operator and the patient, defining the appropriate position in the SVC, and less surgical time. (c) 2007 Wiley-Liss, Inc.

CT fluoroscopy-assisted puncture of thoracic and abdominal masses: a randomized trial.

PubMed

Kirchner, Johannes; Kickuth, Ralph; Laufer, Ulf; Schilling, Esther Maria; Adams, Stephan; Liermann, Dieter

2002-03-01

We investigated the benefit of real-time guidance of interventional punctures by means of computed tomography fluoroscopy (CTF) compared with the conventional sequential acquisition guidance. In a prospective randomized trial, 75 patients underwent either CTF-guided (group A, n = 50) or sequential CT-guided (group B, n = 25) punctures of thoracic (n = 29) or abdominal (n = 46) masses. CTF was performed on the CT machine (Somatom Plus 4 Power, Siemens Corp., Forchheim, Germany) equipped with the C.A.R.E. Vision application (tube voltage 120 kV, tube current 50 mA, rotational time 0.75 s, slice thickness 10 mm, 8 frames/s). The average procedure time showed a statistically significant difference between the two study groups (group A: 564 s, group B 795 s, P = 0.0032). The mean total mAs was 7089 mAs for the CTF and 4856 mAs for the sequential image-guided intervention, respectively. The sensitivity was 71% specificity 100% positive predictive value 100% and negative predictive value 60% for the CTF-guided puncture, and 68, 100, 100 and 50% for sequential CT, respectively. CTF guidance realizes a time-saving but increases the radiation exposure dosage.

Echocardiographic and Fluoroscopic Fusion Imaging for Procedural Guidance: An Overview and Early Clinical Experience.

PubMed

Thaden, Jeremy J; Sanon, Saurabh; Geske, Jeffrey B; Eleid, Mackram F; Nijhof, Niels; Malouf, Joseph F; Rihal, Charanjit S; Bruce, Charles J

2016-06-01

There has been significant growth in the volume and complexity of percutaneous structural heart procedures in the past decade. Increasing procedural complexity and accompanying reliance on multimodality imaging have fueled the development of fusion imaging to facilitate procedural guidance. The first clinically available system capable of echocardiographic and fluoroscopic fusion for real-time guidance of structural heart procedures was approved by the US Food and Drug Administration in 2012. Echocardiographic-fluoroscopic fusion imaging combines the precise catheter and device visualization of fluoroscopy with the soft tissue anatomy and color flow Doppler information afforded by echocardiography in a single image. This allows the interventionalist to perform precise catheter manipulations under fluoroscopy guidance while visualizing critical tissue anatomy provided by echocardiography. However, there are few data available addressing this technology's strengths and limitations in routine clinical practice. The authors provide a critical review of currently available echocardiographic-fluoroscopic fusion imaging for guidance of structural heart interventions to highlight its strengths, limitations, and potential clinical applications and to guide further research into value of this emerging technology. Copyright © 2016 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.

Significant Improvement of Puncture Accuracy and Fluoroscopy Reduction in Percutaneous Transforaminal Endoscopic Discectomy With Novel Lumbar Location System: Preliminary Report of Prospective Hello Study.

PubMed

Fan, Guoxin; Guan, Xiaofei; Zhang, Hailong; Wu, Xinbo; Gu, Xin; Gu, Guangfei; Fan, Yunshan; He, Shisheng

2015-12-01

Prospective nonrandomized control study.The study aimed to investigate the implication of the HE's Lumbar LOcation (HELLO) system in improving the puncture accuracy and reducing fluoroscopy in percutaneous transforaminal endoscopic discectomy (PTED).Percutaneous transforaminal endoscopic discectomy is one of the most popular minimally invasive spine surgeries that heavily depend on repeated fluoroscopy. Increased fluoroscopy will induce higher radiation exposure to surgeons and patients. Accurate puncture in PTED can be achieved by accurate preoperative location and definite trajectory.The HELLO system mainly consists of self-made surface locator and puncture-assisted device. The surface locator was used to identify the exact puncture target and the puncture-assisted device was used to optimize the puncture trajectory. Patients who had single L4/5 or L5/S1 lumbar intervertebral disc herniation and underwent PTED were included the study. Patients receiving the HELLO system were assigned in Group A, and those taking conventional method were assigned in Group B. Study primary endpoint was puncture times and fluoroscopic times, and the secondary endpoint was location time and operation time.A total of 62 patients who received PTED were included in this study. The average age was 45.35 ± 8.70 years in Group A and 46.61 ± 7.84 years in Group B (P = 0.552). There were no significant differences in gender, body mass index, conservative time, and surgical segment between the 2 groups (P > 0.05). The puncture times were 1.19 ± 0.48 in Group A and 6.03 ± 1.87 in Group B (P < 0.001). The fluoroscopic times were 14.03 ± 2.54 in Group A and 25.19 ± 4.28 in Group B (P < 0.001). The preoperative location time was 4.67 ± 1.41 minutes in Group A and 6.98 ± 0.94 minutes in Group B (P < 0.001). The operation time was 79.42 ± 10.15 minutes in Group A and 89.65 ± 14.06 minutes in Group B (P = 0.002). The hospital stay was 2.77 ± 0.95 days in Group A and 2.87 ± 1.02 days in Group B (P = 0.702). There were no significant differences in the complication rate between the 2 groups (P = 0.386).The highlight of HELLO system is accurate preoperative location and definite trajectory. This preliminary report indicated that the HELLO system significantly improves the puncture accuracy of PTED and reduces the fluoroscopic times, preoperative location time, as well as operation time. (ChiCTR-ICR-15006730).

WE-A-12A-01: Medical Physics 1.0 to 2.0, Session 2: Radiography, Mammography and Fluoroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gingold, E; Karellas, A; Strauss, K

Medical Physics 2.0 is a bold vision for an existential transition of clinical imaging physics in face of the new realities of value-based and evidencebased medicine, comparative effectiveness, and meaningful use. It speaks to how clinical imaging physics can expand beyond traditional insular models of inspection and acceptance testing, oriented toward compliance, towards team-based models of operational engagement, prospective definition and assurance of effective use, and retrospective evaluation of clinical performance. Organized into four sessions of the AAPM, this particular session focuses on three specific modalities as outlined below. Radiography 2.0: The development of electronic capture in recent years hasmore » changed the landscape and spurred reinvestment by healthcare providers. The radiography presentation will explore how the diagnostic medical physicist must adapt to these changes to support radiographic imaging, and how she/he can add value in radiography practice over the next 5-10 years. Topics of discussion include new metrology of evaluation, new models of clinical engagement, and effective integration of new technologies. Mammography 2.0: Mammography has been an interesting testing ground on the effectiveness of close involvement of medical physicists with equipment in the past twenty years. The outcomes have clearly shown major improvements in image quality and significant reduction in the average glandular dose. However, the medical physicist's role in mammography has been largely focused to annual surveys and with limited input on operational issues with image artifacts, optimal mammographic acquisition mode and problems with image quality. This mammography presentation will address why and how medical physicists must be prepared to address the new models of practice that include new metrics of performance and the integration of new technologies (DBT, syncretized mammograms, contrast mammography, breast CT) into clinical practice. Fluoroscopy 2.0: Physics support of fluoroscopy should be operationally as opposed to compliance focused. Testing protocols must address new hardware, acquisition methods, and image processing. Future available tools are discussed. Proper configuration of acquisition parameters (focal spot size, voltage and added filter, tube current, pulse width, pulse rate, scatter removal) as a function of patient size from the neonate to bariatric patient is key to providing diagnostic image quality at properly managed radiation doses. Learning Objectives: Appreciate the limitations of the currently available tools and techniques in clinical medical physics in radiography, mammography, and fluoroscopy, and ways to improve upon current deficiencies. Appreciate the changing environment of imaging practice and the need for the medical physicist to be an expert consultant and educator in a capacity that extends beyond the annual survey of equipment. Understand the status of the rapidly changing environment in breast imaging from planar imaging to tomosynthesis and possibly to breast CT. Identify appropriate configuration of acquisition parameters as a function of patient size to manage radiation dose and ensure diagnostic image quality.« less

Comprehensive evaluation of broad-beam transmission of patient supports from three fluoroscopy-guided interventional systems.

PubMed

DeLorenzo, Matthew C; Yang, Kai; Li, Xinhua; Liu, Bob

2018-04-01

The purpose of the study was to measure, evaluate, and model the broad-beam x-ray transmission of the patient supports from representative modern fluoroscopy-guided interventional systems, for patient skin dose calculation. Broad-beam transmission was evaluated by varying incident angle, kVp, added copper (Cu) filter, and x-ray field size for three fluoroscopy systems: General Electric (GE) Innova 4100 with Omega V table and pad, Siemens Axiom Artis with Siemens tabletop "narrow" (CARD) table and pad, and Siemens Zeego with Trumpf TruSystem 7500 table and pad. Field size was measured on the table using a lead ruler for all setups in this study. Exposure rates were measured in service mode using a calibrated Radcal 10 × 6-60 ion chamber above the patient support at the assumed skin location. Broad-beam transmission factors were calculated by the ratio of air kerma rates measured with and without a patient support in the beam path. First, angle dependency was investigated on the GE system, with the chamber at isocenter, for angles of 0°, 15°, 30°, and 40°, for a variety of kVp, added Cu filters, and for two field sizes (small and large). Second, the broad-beam transmission factor at normal incidence was evaluated for all three fluoroscopes by varying kVp, added Cu filter, and field size (small, medium, and large). An analytical equation was created to fit the data as to maximize R 2 and minimize maximum percentage difference across all measurements for each system. For all patient supports, broad-beam transmission factor increased with field size, kVp, and added Cu filtration and decreased with incident angle. Oblique incidence measurements show that the transmission decreased by about 1%, 3%, and 6% for incident angles of 15°, 30°, and 40°, respectively. The broad-beam transmission factors at 0° for the table and table plus pad ranged from 0.73 to 0.96 and from 0.59 to 0.89, respectively. The GE and Siemens transmission factors were comparable, while the Trumpf transmission factors were the lowest. The data were successfully fitted to a function of angle, field size, kVp, and added Cu filtration using nine parameters, with an average R 2 value of 0.977 and maximum percentage difference of 4.08%. This study evaluated the broad-beam transmission for three representative fluoroscopy systems and their dependency on angle, kVp, added Cu filter, and field size. The comprehensive data provided for patient support transmission will facilitate accurate calculation of peak skin dose (PSD) and may potentially be integrated into real-time and retrospective dose monitoring with access to Radiation Dose Structured Reports (RDSR) and radiation event data. © 2018 American Association of Physicists in Medicine.

New Image-Based Techniques for Prostate Biopsy and Treatment

DTIC Science & Technology

2012-04-01

C-arm fluoroscopy, MICCAI 2011, Toronto, Canada, 2011. 4) Poster Presentation: Prostate Cancer Probability Estimation Based on DCE- DTI Features...and P. Kozlowski, “Prostate Cancer Probability Estimation Based on DCE- DTI Features and Support Vector Machine Classification,” Annual Meeting of... DTI ), which characterize the de-phasing of the MR signal caused by molecular diffusion. Prostate cancer causes a pathological change in the tissue

"More may mean less... " the role for simulation-based medical education in the cardiac catheterization laboratory.

PubMed

Westerdahl, Daniel E; Henry, Timothy D

2016-02-15

Implementation of simulation-based medical education (SBME) can improve cardiovascular fellows' angiography skills and knowledge SBME focused on performing coronary angiography shortened procedure times and decreased the use of cine-fluoroscopy The ACGME mandate and SCAI's Simulation Committee recommendations suggest SBME will play an expanding and integral role in the field of cardiovascular medicine. © 2016 Wiley Periodicals, Inc.

Effectiveness of sonography assisted minimal invasive plate osteosynthesis (MIPO) compare with fluoroscope assisted in femoral shaft fracture: A cadaveric study.

PubMed

Saengsin, Jirawat; Vaseenon, Tanawat; Pattamapaspong, Nuttaya; Kritsaneephaiboon, Apipop

2017-08-01

A minimal invasive plate osteosynthesis (MIPO) has an advantage of biological soft tissue preservation that consists of preserving bony blood supply, fracture hematoma and less soft tissue damage which leads to decreasing of infection rate and rapid bone healing. However, the radiation exposure is still a disadvantage of this technique. A sonography that provides dynamic real time imaging may be used as an alternative technique for assisting MIPO. The aim of this study was to compare the effectiveness of MIPO in femoral shaft fracture between the sonography assisted and the fluoroscopy assisted. Twenty-eight cadaveric limbs were subjected to create femoral shaft fracture. Then, sonography assisted reduction with temporary external fixation and MIPO were performed. Images of the sonography and the fluoroscopy were recorded including before reduction, after reduction and after MIPO in order to identify fracture displacements in anteroposterior and mediolateral directions. Moreover, the anterior and posterior distances from edge of the bone to the plate were measured to confirm plate position. The effectiveness of this technique was defined as the proper plate position and acceptable alignment after fixation. All distances from the sonography and the fluoroscopy were also analyzed and compared using Pearson correlation and Bland-Altman method to assess the agreements between two tests. All of the subjects were met the criteria for acceptable alignment. We found only three femoral shaft fracture (11%) operated with MIPO by sonography assisted that showed slipped plate off femoral bones. According to Pearson correlation, there were good to excellent agreements in term of measuring fracture displacement before (Pearson Correlation >0.7) and after reduction (Pearson Correlation >0.7) between these two tests. There was moderate agreement regarding to evaluation of plate position (Pearson Correlation 03.-0.7). When we compared two methods of measurement using Bland-Altman plot, there were no statistical significant difference (P<0.05). Images from the sonography could provide visualization of the fracture during reduction and MIPO as accurately as the radiography. Thus, the sonography assisted MIPO in femoral shaft fracture can be done effectively comparing with radiographic assisted. Copyright © 2017 Elsevier Ltd. All rights reserved.

Impact of Anatomical, Procedural, and Operator Skill Factors on the Success and Duration of Fluoroscopy-Guided Transjugular Intrahepatic Portosystemic Shunt

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marquardt, Steffen, E-mail: marquardt.steffen@mh-hannover.de; Rodt, Thomas, E-mail: rodt.thomas@mh-hannover.de; Rosenthal, Herbert, E-mail: rosenthal.herbert@mh-hannover.de

PurposeTo assess the impact of anatomical, procedural, and operator skill factors on the success and duration of fluoroscopy-guided transjugular intrahepatic portoystemic shunt following standard operating procedure (SOP).Material and MethodsDuring a 32-month period, 102 patients underwent transjugular intrahepatic portosystemic shunt creation (TIPS) by two interventional radiologists (IR) following our institutional SOP based on fluoroscopy guidance. Both demographic and procedural data were assessed. The duration of the intervention (D{sub Int}) and of the portal vein puncture (D{sub Punct}) was analyzed depending on the skill level of the IR as well as the anatomic or procedural factors.ResultsIn 99 of the 102 patients, successfulmore » TIPS without peri-procedural complications was performed. The mean D{sub Int} (IR1: 77 min; IR2: 51 min, P < 0.005) and the mean D{sub Punct} (IR1: 19 min; IR2: 13 min, P < 0.005) were significantly higher in TIPS performed by IR1 (with 2 years of clinical experience performing TIPS, n = 38) than by IR2 (>10 years of clinical experience performing TIPS, n = 61), (P < 0.005 both, Mann–Whitney U test). D{sub Int} showed a higher correlation with D{sub Punct} for IR2 (R{sup 2} = 0.63) than for IR1 (R{sup 2} = 0.13). There was no significant difference in the D{sub Punct} for both IRs with regard to the success of the wedged portography (P = 0.90), diameter of the portal vein (P = 0.60), central right portal vein length (P = 0.49), or liver function (MELD-Score before the TIPS procedure; P = 0.14).ConclusionTIPS following SOP is safe, fast, and reliable. The only significant factor for shorter D{sub Punct} and D{sub Int} was the clinical experience of the IR. Anatomic variability, successful portography, or liver function did not alter the duration or technical success of TIPS.« less

Direct-conversion flat-panel imager with avalanche gain: Feasibility investigation for HARP-AMFPI

PubMed Central

Wronski, M. M.; Rowlands, J. A.

2008-01-01

The authors are investigating the concept of a direct-conversion flat-panel imager with avalanche gain for low-dose x-ray imaging. It consists of an amorphous selenium (a-Se) photoconductor partitioned into a thick drift region for x-ray-to-charge conversion and a relatively thin region called high-gain avalanche rushing photoconductor (HARP) in which the charge undergoes avalanche multiplication. An active matrix of thin film transistors is used to read out the electronic image. The authors call the proposed imager HARP active matrix flat panel imager (HARP-AMFPI). The key advantages of HARP-AMFPI are its high spatial resolution, owing to the direct-conversion a-Se layer, and its programmable avalanche gain, which can be enabled during low dose fluoroscopy to overcome electronic noise and disabled during high dose radiography to prevent saturation of the detector elements. This article investigates key design considerations for HARP-AMFPI. The effects of electronic noise on the imaging performance of HARP-AMFPI were modeled theoretically and system parameters were optimized for radiography and fluoroscopy. The following imager properties were determined as a function of avalanche gain: (1) the spatial frequency dependent detective quantum efficiency; (2) fill factor; (3) dynamic range and linearity; and (4) gain nonuniformities resulting from electric field strength nonuniformities. The authors results showed that avalanche gains of 5 and 20 enable x-ray quantum noise limited performance throughout the entire exposure range in radiography and fluoroscopy, respectively. It was shown that HARP-AMFPI can provide the required gain while maintaining a 100% effective fill factor and a piecewise dynamic range over five orders of magnitude (10−7–10−2 R∕frame). The authors have also shown that imaging performance is not significantly affected by the following: electric field strength nonuniformities, avalanche noise for x-ray energies above 1 keV and direct interaction of x rays in the gain region. Thus, HARP-AMFPI is a promising flat-panel imager structure that enables high-resolution fully quantum noise limited x-ray imaging over a wide exposure range. PMID:19175080

SU-E-I-55: The Contribution to Skin Dose Due to Scatter From the Patient Table and the Head Holder During Fluoroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Islam, N; Xiong, Z; Vijayan, S

2015-06-15

Purpose: To determine contributions to skin dose due to scatter from the table and head holder used during fluoroscopy, and also to explore alternative design material to reduce the scatter dose. Methods: Measurements were made of the primary and scatter components of the xray beam exiting the patient table and a cylindrical head holder used on a Toshiba Infinix c-arm unit as a function of kVp for the various beam filters on the machine and for various field sizes. The primary component of the beam was measured in air with the object placed close to the x-ray tube with anmore » air gap between it and a 6 cc parallel-plate ionization chamber and with the beam collimated to a size just larger than the chamber. The primary plus scatter radiation components were measured with the object moved to a position in the beam next to the chamber for larger field sizes. Both sets of measurements were preformed while keeping the source-to-chamber distance fixed. The scatter fraction was estimated by taking the ratio of the difference between the two measurements and the reading that included both primary and scatter. Similar measurements were also made for a 2.3 cm thick Styrofoam block which could substitute for the patient support. Results: The measured scatter fractions indicate that the patient table as well as the head holder contributes an additional 10–16% to the patient entrance dose depending on field size. Forward scatter was reduced with the Styrofoam block so that the scatter fraction was about 4–5%. Conclusion: The results of this investigation demonstrated that scatter from the table and head holder used in clinical fluoroscopy contribute substantially to the skin dose. The lower contribution of scatter from Styrofoam suggests that there is an opportunity to redesign patient support accessories to reduce the skin dose. Partial support from NIH grant R01EB002873 and Toshiba Medical Systems Corporation Equipment Grant.« less

Efficacy of RADPAD® protection drape in reducing radiation exposure to the primary operator during Transcatheter Aortic Valve Implantation (TAVI).

PubMed

Sharma, Divyesh; Ramsewak, Adesh; Manoharan, Ganesh; Spence, Mark S

2016-02-01

The efficacy of RADPAD® (a sterile, lead-free drape) has been demonstrated to reduce the scatter radiation to the primary operator during fluoroscopic procedures. However, the use of the RADPAD® during TAVI procedures has not been studied. Transcatheter aortic valve implantation (TAVI) is now an established treatment for patients with symptomatic severe aortic stenosis who are deemed inoperable or at high risk for conventional surgical aortic valve replacement (AVR). Consequently the radiation exposure to the patient and the interventional team from this procedure has become a matter of interest and importance. Methods to reduce radiation exposure to the interventional team during this procedure should be actively investigated. In this single center prospective study, we determined the radiation dose during this procedure and the efficacy of RADPAD® in reducing the radiation dose to the primary operator. Fifty consecutive patients due to undergo elective TAVI procedures were identified. Patients were randomly assigned to undergo the procedure with or without the use of a RADPAD® drape. There were 25 patients in each group and dosimetry was performed at the left eye level of the primary operator. The dosimeter was commenced at the start of the procedure, and the dose was recorded immediately after the end of the procedure. Fluoroscopy times and DAP were also recorded prospectively. Twenty-five patients underwent transfemoral TAVI using a RADPAD® and 25 with no-RADPAD®. The mean primary operator radiation dose was significantly lower in the RADPAD group at 14.8 mSv vs. 24.3 mSv in the no-RADPAD group (P=0.008). There was no significant difference in fluoroscopy times or dose-area products between the two patient groups. The dose to the primary operator relative to fluoroscopy time (RADPAD: slope=0.325; no RADPAD: slope=1.148; analysis of covariance F=7.47, P=0.009) and dose area product (RADPAD: slope=0.0007; no RADPAD: slope=0.002; analysis of covariance F=7.38; P=0.009) was smaller in the RADPAD group compared to no-RADPAD group. Use of a RADPAD® significantly reduces radiation exposure to the primary operator during TAVI procedures.

SU-G-JeP3-01: A Method to Quantify Lung SBRT Target Localization Accuracy Based On Digitally Reconstructed Fluoroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lafata, K; Ren, L; Cai, J

2016-06-15

Purpose: To develop a methodology based on digitally-reconstructed-fluoroscopy (DRF) to quantitatively assess target localization accuracy of lung SBRT, and to evaluate using both a dynamic digital phantom and a patient dataset. Methods: For each treatment field, a 10-phase DRF is generated based on the planning 4DCT. Each frame is pre-processed with a morphological top-hat filter, and corresponding beam apertures are projected to each detector plane. A template-matching algorithm based on cross-correlation is used to detect the tumor location in each frame. Tumor motion relative beam aperture is extracted in the superior-inferior direction based on each frame’s impulse response to themore » template, and the mean tumor position (MTP) is calculated as the average tumor displacement. The DRF template coordinates are then transferred to the corresponding MV-cine dataset, which is retrospectively filtered as above. The treatment MTP is calculated within each field’s projection space, relative to the DRF-defined template. The field’s localization error is defined as the difference between the DRF-derived-MTP (planning) and the MV-cine-derived-MTP (delivery). A dynamic digital phantom was used to assess the algorithm’s ability to detect intra-fractional changes in patient alignment, by simulating different spatial variations in the MV-cine and calculating the corresponding change in MTP. Inter-and-intra-fractional variation, IGRT accuracy, and filtering effects were investigated on a patient dataset. Results: Phantom results demonstrated a high accuracy in detecting both translational and rotational variation. The lowest localization error of the patient dataset was achieved at each fraction’s first field (mean=0.38mm), with Fx3 demonstrating a particularly strong correlation between intra-fractional motion-caused localization error and treatment progress. Filtering significantly improved tracking visibility in both the DRF and MV-cine images. Conclusion: We have developed and evaluated a methodology to quantify lung SBRT target localization accuracy based on digitally-reconstructed-fluoroscopy. Our approach may be useful in potentially reducing treatment margins to optimize lung SBRT outcomes. R01-184173.« less

Direct-conversion flat-panel imager with avalanche gain: Feasibility investigation for HARP-AMFPI

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wronski, M. M.; Rowlands, J. A.

2008-12-15

The authors are investigating the concept of a direct-conversion flat-panel imager with avalanche gain for low-dose x-ray imaging. It consists of an amorphous selenium (a-Se) photoconductor partitioned into a thick drift region for x-ray-to-charge conversion and a relatively thin region called high-gain avalanche rushing photoconductor (HARP) in which the charge undergoes avalanche multiplication. An active matrix of thin film transistors is used to read out the electronic image. The authors call the proposed imager HARP active matrix flat panel imager (HARP-AMFPI). The key advantages of HARP-AMFPI are its high spatial resolution, owing to the direct-conversion a-Se layer, and its programmablemore » avalanche gain, which can be enabled during low dose fluoroscopy to overcome electronic noise and disabled during high dose radiography to prevent saturation of the detector elements. This article investigates key design considerations for HARP-AMFPI. The effects of electronic noise on the imaging performance of HARP-AMFPI were modeled theoretically and system parameters were optimized for radiography and fluoroscopy. The following imager properties were determined as a function of avalanche gain: (1) the spatial frequency dependent detective quantum efficiency; (2) fill factor; (3) dynamic range and linearity; and (4) gain nonuniformities resulting from electric field strength nonuniformities. The authors results showed that avalanche gains of 5 and 20 enable x-ray quantum noise limited performance throughout the entire exposure range in radiography and fluoroscopy, respectively. It was shown that HARP-AMFPI can provide the required gain while maintaining a 100% effective fill factor and a piecewise dynamic range over five orders of magnitude (10{sup -7}-10{sup -2} R/frame). The authors have also shown that imaging performance is not significantly affected by the following: electric field strength nonuniformities, avalanche noise for x-ray energies above 1 keV and direct interaction of x rays in the gain region. Thus, HARP-AMFPI is a promising flat-panel imager structure that enables high-resolution fully quantum noise limited x-ray imaging over a wide exposure range.« less

Radiation Exposure and Vascular Access in Acute Coronary Syndromes: The RAD-Matrix Trial.

PubMed

Sciahbasi, Alessandro; Frigoli, Enrico; Sarandrea, Alessandro; Rothenbühler, Martina; Calabrò, Paolo; Lupi, Alessandro; Tomassini, Francesco; Cortese, Bernardo; Rigattieri, Stefano; Cerrato, Enrico; Zavalloni, Dennis; Zingarelli, Antonio; Calabria, Paolo; Rubartelli, Paolo; Sardella, Gennaro; Tebaldi, Matteo; Windecker, Stephan; Jüni, Peter; Heg, Dik; Valgimigli, Marco

2017-05-23

It remains unclear whether radial access increases the risk of operator or patient radiation exposure compared to transfemoral access when performed by expert operators. This study sought to determine whether radial access increases radiation exposure. A total of 8,404 patients, with or without ST-segment elevation acute coronary syndrome, were randomly assigned to radial or femoral access for coronary angiography and percutaneous intervention, and collected fluoroscopy time and dose-area product (DAP). RAD-MATRIX is a radiation sub-study of the MATRIX (Minimizing Adverse Haemorrhagic Events by Transradial Access Site and Systemic Implementation of AngioX) trial. We anticipated that 13 or more operators, each wearing a thorax (primary endpoint), wrist, and head (secondary endpoints) lithium fluoride thermoluminescent dosimeter, and randomizing at least 13 patients per access site, were needed to establish noninferiority of radial versus femoral access. Among 18 operators, performing 777 procedures in 767 patients, the noninferiority primary endpoint was not achieved (p value for noninferiority = 0.843). Operator equivalent dose at the thorax (77 μSv) was significantly higher with radial than femoral access (41 μSv; p = 0.02). After normalization of operator radiation dose by fluoroscopy time or DAP, the difference remained significant. Radiation dose at wrist or head did not differ between radial and femoral access. Thorax operator dose did not differ for right radial (84 μSv) compared to left radial access (52 μSv; p = 0.15). In the overall MATRIX population, fluoroscopy time and DAP were higher with radial compared to femoral access: 10 min versus 9 min (p < 0.0001) and 65 Gy·cm 2 versus 59 Gy·cm 2 (p = 0.0001), respectively. Compared to femoral access, radial access is associated with greater operator and patient radiation exposure when performed by expert operators in current practice. Radial operators and institutions should be sensitized towards radiation risks and adopt adjunctive radioprotective measures. (Minimizing Adverse Haemorrhagic Events by Transradial Access Site and Systemic Implementation of AngioX; NCT101433627). Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Tracker-on-C for cone-beam CT-guided surgery: evaluation of geometric accuracy and clinical applications

NASA Astrophysics Data System (ADS)

Reaungamornrat, S.; Otake, Y.; Uneri, A.; Schafer, S.; Mirota, D. J.; Nithiananthan, S.; Stayman, J. W.; Khanna, A. J.; Reh, D. D.; Gallia, G. L.; Taylor, R. H.; Siewerdsen, J. H.

2012-02-01

Conventional surgical tracking configurations carry a variety of limitations in line-of-sight, geometric accuracy, and mismatch with the surgeon's perspective (for video augmentation). With increasing utilization of mobile C-arms, particularly those allowing cone-beam CT (CBCT), there is opportunity to better integrate surgical trackers at bedside to address such limitations. This paper describes a tracker configuration in which the tracker is mounted directly on the Carm. To maintain registration within a dynamic coordinate system, a reference marker visible across the full C-arm rotation is implemented, and the "Tracker-on-C" configuration is shown to provide improved target registration error (TRE) over a conventional in-room setup - (0.9+/-0.4) mm vs (1.9+/-0.7) mm, respectively. The system also can generate digitally reconstructed radiographs (DRRs) from the perspective of a tracked tool ("x-ray flashlight"), the tracker, or the C-arm ("virtual fluoroscopy"), with geometric accuracy in virtual fluoroscopy of (0.4+/-0.2) mm. Using a video-based tracker, planning data and DRRs can be superimposed on the video scene from a natural perspective over the surgical field, with geometric accuracy (0.8+/-0.3) pixels for planning data overlay and (0.6+/-0.4) pixels for DRR overlay across all C-arm angles. The field-of-view of fluoroscopy or CBCT can also be overlaid on real-time video ("Virtual Field Light") to assist C-arm positioning. The fixed transformation between the x-ray image and tracker facilitated quick, accurate intraoperative registration. The workflow and precision associated with a variety of realistic surgical tasks were significantly improved using the Tracker-on-C - for example, nearly a factor of 2 reduction in time required for C-arm positioning, reduction or elimination of dose in "hunting" for a specific fluoroscopic view, and confident placement of the x-ray FOV on the surgical target. The proposed configuration streamlines the integration of C-arm CBCT with realtime tracking and demonstrated utility in a spectrum of image-guided interventions (e.g., spine surgery) benefiting from improved accuracy, enhanced visualization, and reduced radiation exposure.

SU-C-BRF-05: Design and Geometric Validation of An Externally and Internally Deformable, Programmable Lung Motion Phantom

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheung, Y; Sawant, A

Purpose: Most clinically-deployed strategies for respiratory motion management in lung radiotherapy (e.g., gating, tracking) use external markers that serve as surrogates for tumor motion. However, typical lung phantoms used to validate these strategies are rigid-exterior+rigid-interior or rigid-exterior+deformable-interior. Neither class adequately represents the human anatomy, which is deformable internally as well as externally. We describe the construction and experimental validation of a more realistic, externally- and internally-deformable, programmable lung phantom. Methods: The outer shell of a commercially-available lung phantom (RS- 1500, RSD Inc.) was used. The shell consists of a chest cavity with a flexible anterior surface, and embedded vertebrae, rib-cagemore » and sternum. A 3-axis platform was programmed with sinusoidal and six patient-recorded lung tumor trajectories. The platform was used to drive a rigid foam ‘diaphragm’ that compressed/decompressed the phantom interior. Experimental characterization comprised of mapping the superior-inferior (SI) and anterior-posterior (AP) trajectories of external and internal radioopaque markers with kV x-ray fluoroscopy and correlating these with optical surface monitoring using the in-room VisionRT system. Results: The phantom correctly reproduced the programmed motion as well as realistic effects such as hysteresis. The reproducibility of marker trajectories over multiple runs for sinusoidal as well as patient traces, as characterized by fluoroscopy, was within 0.4 mm RMS error for internal as well as external markers. The motion trajectories of internal and external markers as measured by fluoroscopy were found to be highly correlated (R=0.97). Furthermore, motion trajectories of arbitrary points on the deforming phantom surface, as recorded by the VisionRT system also showed a high correlation with respect to the fluoroscopically-measured trajectories of internal markers (R=0.92). Conclusion: We have developed a realistic externally- and internally-deformable lung phantom that will serve as a valuable tool for clinical QA and motion management research. This work was supported through funding from the NIH and VisionRT Ltd. Amit Sawant has research funding from Varian Medical Systems, VisionRT and Elekta.« less

Evaluation of a new very low dose imaging protocol: feasibility and impact on X-ray dose levels in electrophysiology procedures

PubMed Central

Bourier, Felix; Reents, Tilko; Ammar-Busch, Sonia; Buiatti, Alessandra; Kottmaier, Marc; Semmler, Verena; Telishevska, Marta; Brkic, Amir; Grebmer, Christian; Lennerz, Carsten; Kolb, Christof; Hessling, Gabriele; Deisenhofer, Isabel

2016-01-01

Aims This study presents and evaluates the impact of a new lowest-dose fluoroscopy protocol (Siemens AG), especially designed for electrophysiology (EP) procedures, on X-ray dose levels. Methods and results From October 2014 to March 2015, 140 patients underwent an EP study on an Artis zee angiography system. The standard low-dose protocol was operated at 23 nGy (fluoroscopy) and at 120 nGy (cine-loop), the new lowest-dose protocol was operated at 8 nGy (fluoroscopy) and at 36 nGy (cine-loop). Procedural data, X-ray times, and doses were analysed in 100 complex left atrial and in 40 standard EP procedures. The resulting dose–area products were 877.9 ± 624.7 µGym² (n = 50 complex procedures, standard low dose), 199 ± 159.6 µGym² (n = 50 complex procedures, lowest dose), 387.7 ± 36.0 µGym² (n = 20 standard procedures, standard low dose), and 90.7 ± 62.3 µGym² (n = 20 standard procedures, lowest dose), P < 0.01. In the low-dose and lowest-dose groups, procedure times were 132.6 ± 35.7 vs. 126.7 ± 34.7 min (P = 0.40, complex procedures) and 72.3 ± 20.9 vs. 85.2 ± 44.1 min (P = 0.24, standard procedures), radiofrequency (RF) times were 53.8 ± 26.1 vs. 50.4 ± 29.4 min (P = 0.54, complex procedures) and 10.1 ± 9.9 vs. 12.2 ± 14.7 min (P = 0.60, standard procedures). One complication occurred in the standard low-dose and lowest-dose groups (P = 1.0). Conclusion The new lowest-dose imaging protocol reduces X-ray dose levels by 77% compared with the currently available standard low-dose protocol. From an operator standpoint, lowest X-ray dose levels create a different, reduced image quality. The new image quality did not significantly affect procedure or RF times and did not result in higher complication rates. Regarding radiological protection, operating at lowest-dose settings should become standard in EP procedures. PMID:26589627

Effective dose estimation for pediatric upper gastrointestinal examinations using an anthropomorphic phantom set and metal oxide semiconductor field-effect transistor (MOSFET) technology.

PubMed

Emigh, Brent; Gordon, Christopher L; Connolly, Bairbre L; Falkiner, Michelle; Thomas, Karen E

2013-09-01

There is a need for updated radiation dose estimates in pediatric fluoroscopy given the routine use of new dose-saving technologies and increased radiation safety awareness in pediatric imaging. To estimate effective doses for standardized pediatric upper gastrointestinal (UGI) examinations at our institute using direct dose measurement, as well as provide dose-area product (DAP) to effective dose conversion factors to be used for the estimation of UGI effective doses for boys and girls up to 10 years of age at other centers. Metal oxide semiconductor field-effect transistor (MOSFET) dosimeters were placed within four anthropomorphic phantoms representing children ≤10 years of age and exposed to mock UGI examinations using exposures much greater than used clinically to minimize measurement error. Measured effective dose was calculated using ICRP 103 weights and scaled to our institution's standardized clinical UGI (3.6-min fluoroscopy, four spot exposures and four examination beam projections) as determined from patient logs. Results were compared to Monte Carlo simulations and related to fluoroscope-displayed DAP. Measured effective doses for standardized pediatric UGI examinations in our institute ranged from 0.35 to 0.79 mSv in girls and were 3-8% lower for boys. Simulation-derived and measured effective doses were in agreement (percentage differences <19%, T > 0.18). DAP-to-effective dose conversion factors ranged from 6.5 ×10(-4) mSv per Gy-cm(2) to 4.3 × 10(-3) mSv per Gy-cm(2) for girls and were similarly lower for boys. Using modern fluoroscopy equipment, the effective dose associated with the UGI examination in children ≤10 years at our institute is < 1 mSv. Estimations of effective dose associated with pediatric UGI examinations can be made for children up to the age of 10 using the DAP-normalized conversion factors provided in this study. These estimates can be further refined to reflect individual hospital examination protocols through the use of direct organ dose measurement using MOSFETs, which were shown to agree with Monte Carlo simulated doses.

SU-G-IeP3-13: Real-Time Patient and Staff Dose Monitoring in Fluoroscopy Guided Interventions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vergoossen, L; Sailer, A; Paulis, L

Purpose: Interventional radiology procedures involve the use of X-rays, which can pose a large radiation burden on both patients and staff. Although some reports on radiation dose are available, most studies focus on limited types of procedures and only report patient dose. In our cathlabs a dedicated real-time patient and staff monitoring system was installed in November 2015. The aim of this study was to investigate the patient and staff dose exposure for different types of interventions. Methods: Radiologists involved in fluoroscopy guided interventional radiology procedures wore personal dose meters (PDM, DoseAware, Philips) on their lead-apron that measured the personalmore » dose equivalent Hp(10), a measure for the effective dose (E). Furthermore, reference PDMs were installed in the C-arms of the fluoroscopy system (Allura XPer, Philips). Patient dose-area-product (DAP) and PDM doses were retrieved from the monitoring system (DoseWise, Philips) for each procedure. A total of 399 procedures performed between November 2015 and February 2016 were analyzed with respect to the type of intervention. Interventions were grouped by anatomy and radiologist position. Results: The mean DAP for the different types of interventions ranged from 2.86±2.96 Gycm{sup 2} (percutaneous gastrostomy) to 147±178 Gycm{sup 2} (aortic repair procedures). The radiologist dose (E) ranged from 5.39±7.38 µSv (cerebral interventions) to 84.7±106 µSv (abdominal interventions) and strongly correlated with DAP (R{sup 2}=0.83). The E normalized to DAP showed that the relative radiologist dose was higher for interventions in larger body parts (e.g. abdomen) compared to smaller body parts (e.g. head). Conclusion: Using a real-time dose monitoring system we were able to assess the staff and patient dose revealing that the relative staff dose strongly depended on the type of procedure and patient anatomy. This could be explained by the position of the radiologist with respect to the patient and X-ray tube. To facilitate this study L Vergoossen received a scholarship from Philips Medical Systems.« less

Excessive strut wear allowing ball-poppet embolization in a DeBakey-Surgitool aortic valve prosthesis.

PubMed

Sutherland, R D; Guynes, W A; Nichols, C T; Martinez, H E

1982-01-01

Excessive cage strut wear allowing ball-poppet embolization caused the sudden death of a 47 year old lady in whom a DeBakey-Surgitool aortic prosthesis had been implanted nine years earlier. Patients with this type of prosthesis should have periodic valvular cine fluoroscopy with image intensification to allow visualization of significant strut wear or fracture, and appropriate prosthetic valve replacement.

Technical Note: Thoracic duct embolization for treatment of chylothorax: A novel guidance technique for puncture using combined MRI and fluoroscopy.

PubMed

Praveen, Alampath; Sreekumar, Karumathil Pullara; Nazar, Puthukudiyil Kader; Moorthy, Srikanth

2012-04-01

Thoracic duct embolization (TDE) is an established radiological interventional procedure for thoracic duct injuries. Traditionally, it is done under fluoroscopic guidance after opacifying the thoracic duct with bipedal lymphangiography. We describe our experience in usinga heavily T2W sequence for guiding thoracic duct puncture and direct injection of glue through the puncture needle without cannulating the duct.

Intra-operative Localization of Brachytherapy Implants Using Intensity-based Registration

PubMed Central

KarimAghaloo, Z.; Abolmaesumi, P.; Ahmidi, N.; Chen, T.K.; Gobbi, D. G.; Fichtinger, G.

2010-01-01

In prostate brachytherapy, a transrectal ultrasound (TRUS) will show the prostate boundary but not all the implanted seeds, while fluoroscopy will show all the seeds clearly but not the boundary. We propose an intensity-based registration between TRUS images and the implant reconstructed from uoroscopy as a means of achieving accurate intra-operative dosimetry. The TRUS images are first filtered and compounded, and then registered to the uoroscopy model via mutual information. A training phantom was implanted with 48 seeds and imaged. Various ultrasound filtering techniques were analyzed, and the best results were achieved with the Bayesian combination of adaptive thresholding, phase congruency, and compensation for the non-uniform ultrasound beam profile in the elevation and lateral directions. The average registration error between corresponding seeds relative to the ground truth was 0.78 mm. The effect of false positives and false negatives in ultrasound were investigated by masking true seeds in the uoroscopy volume or adding false seeds. The registration error remained below 1.01 mm when the false positive rate was 31%, and 0.96 mm when the false negative rate was 31%. This fully automated method delivers excellent registration accuracy and robustness in phantom studies, and promises to demonstrate clinically adequate performance on human data as well. Keywords: Prostate brachytherapy, Ultrasound, Fluoroscopy, Registration. PMID:21152376

Increasing the automation of a 2D-3D registration system.

PubMed

Varnavas, Andreas; Carrell, Tom; Penney, Graeme

2013-02-01

Routine clinical use of 2D-3D registration algorithms for Image Guided Surgery remains limited. A key aspect for routine clinical use of this technology is its degree of automation, i.e., the amount of necessary knowledgeable interaction between the clinicians and the registration system. Current image-based registration approaches usually require knowledgeable manual interaction during two stages: for initial pose estimation and for verification of produced results. We propose four novel techniques, particularly suited to vertebra-based registration systems, which can significantly automate both of the above stages. Two of these techniques are based upon the intraoperative "insertion" of a virtual fiducial marker into the preoperative data. The remaining two techniques use the final registration similarity value between multiple CT vertebrae and a single fluoroscopy vertebra. The proposed methods were evaluated with data from 31 operations (31 CT scans, 419 fluoroscopy images). Results show these methods can remove the need for manual vertebra identification during initial pose estimation, and were also very effective for result verification, producing a combined true positive rate of 100% and false positive rate equal to zero. This large decrease in required knowledgeable interaction is an important contribution aiming to enable more widespread use of 2D-3D registration technology.

Three-dimensional innate mobility of the human foot bones under axial loading using biplane X-ray fluoroscopy

PubMed Central

Hosoda, Koh; Shimizu, Masahiro; Ikemoto, Shuhei; Nagura, Takeo; Seki, Hiroyuki; Kitashiro, Masateru; Imanishi, Nobuaki; Aiso, Sadakazu; Jinzaki, Masahiro; Ogihara, Naomichi

2017-01-01

The anatomical design of the human foot is considered to facilitate generation of bipedal walking. However, how the morphology and structure of the human foot actually contribute to generation of bipedal walking remains unclear. In the present study, we investigated the three-dimensional kinematics of the foot bones under a weight-bearing condition using cadaver specimens, to characterize the innate mobility of the human foot inherently prescribed in its morphology and structure. Five cadaver feet were axially loaded up to 588 N (60 kgf), and radiographic images were captured using a biplane X-ray fluoroscopy system. The present study demonstrated that the talus is medioinferiorly translated and internally rotated as the calcaneus is everted owing to axial loading, causing internal rotation of the tibia and flattening of the medial longitudinal arch in the foot. Furthermore, as the talus is internally rotated, the talar head moves medially with respect to the navicular, inducing external rotation of the navicular and metatarsals. Under axial loading, the cuboid is everted simultaneously with the calcaneus owing to the osseous locking mechanism in the calcaneocuboid joint. Such detailed descriptions about the innate mobility of the human foot will contribute to clarifying functional adaptation and pathogenic mechanisms of the human foot. PMID:29134100

Interventional robotic systems: Applications and technology state-of-the-art

PubMed Central

CLEARY, KEVIN; MELZER, ANDREAS; WATSON, VANCE; KRONREIF, GERNOT; STOIANOVICI, DAN

2011-01-01

Many different robotic systems have been developed for invasive medical procedures. In this article we will focus on robotic systems for image-guided interventions such as biopsy of suspicious lesions, interstitial tumor treatment, or needle placement for spinal blocks and neurolysis. Medical robotics is a young and evolving field and the ultimate role of these systems has yet to be determined. This paper presents four interventional robotics systems designed to work with MRI, CT, fluoroscopy, and ultrasound imaging devices. The details of each system are given along with any phantom, animal, or human trials. The systems include the AcuBot for active needle insertion under CT or fluoroscopy, the B-Rob systems for needle placement using CT or ultrasound, the INNOMOTION for MRI and CT interventions, and the MRBot for MRI procedures. Following these descriptions, the technology issues of image compatibility, registration, patient movement and respiration, force feedback, and control mode are briefly discussed. It is our belief that robotic systems will be an important part of future interventions, but more research and clinical trials are needed. The possibility of performing new clinical procedures that the human cannot achieve remains an ultimate goal for medical robotics. Engineers and physicians should work together to create and validate these systems for the benefits of patients everywhere. PMID:16754193

Primary percutaneous coronary intervention by magnetic navigation compared with conventional wire technique.

PubMed

Patterson, Mark S; Dirksen, Maurits T; Ijsselmuiden, Alexander J; Amoroso, Giovanni; Slagboom, Ton; Laarman, Gerrit-Jan; Schultz, Carl; van Domburg, Ron T; Serruys, Patrick W; Kiemeneij, Ferdinand

2011-06-01

Aims Comparison of magnetic guidewire navigation in percutaneous coronary intervention (MPCI) vs. conventional percutaneous coronary intervention (CPCI) for the treatment of acute myocardial infarction. Methods and results We compared 65 sequential patients (mean age 61 ± 15 years) undergoing primary MPCI with those of 405 patients undergoing CPCI (mean age 61 ± 13 years). The major endpoint was contrast media use. Technical success and procedural outcomes were evaluated. Clinical demographics and angiographic characteristics of the two groups were similar, except for fewer patients with previous coronary artery bypass grafting (CABG) and hypertension in the CPCI group and fewer patients with diabetes in the MPCI group. The technical success rate was high in both the MPCI and CPCI groups (95.4 vs. 98%). There was significantly less contrast media usage in the MPCI compared with the CPCI group, median reduction of contrast media of 30 mL with an OR = 0.41 (0.21-0.81). Fluoroscopy times were significantly reduced for MPCI compared with CPCI, median reduction of 7.2 min with an OR = 0.42 (0.20-0.79). Conclusion This comparison indicates the feasibility and non-inferiority of magnetic navigation in performing primary PCI and suggests the possibility of reductions in contrast media use and fluoroscopy time compared with CPCI.

Transjugular intrahepatic portosystemic shunt creation using intravascular ultrasound guidance.

PubMed

Farsad, Khashayar; Fuss, Cristina; Kolbeck, Kenneth J; Barton, Robert E; Lakin, Paul C; Keller, Frederick S; Kaufman, John A

2012-12-01

To describe the use of intravascular ultrasound (US) guidance for creation of transjugular intrahepatic portosystemic shunts (TIPSs) in humans. The initial 25 cases of intravascular US-guided TIPS were retrospectively compared versus the last 75 conventional TIPS cases during the same time period at the same institution in terms of the number of needle passes required to establish portal vein (PV) access, fluoroscopy time, and needle pass-related complications. Intravascular US-guided TIPS creation was successful in all cases, and there was no statistically significant difference in number of needle passes, fluoroscopy time, or needle pass-related complications between TIPS techniques. Intravascular US-guided TIPS creation was successful in cases in which conventional TIPS creation had failed as a result of PV thrombosis or distorted anatomy. Intravascular US guidance for TIPS creation was additionally useful in a patient with Budd-Chiari syndrome and in a patient with intrahepatic tumors. Intravascular US is a safe and reproducible means of real-time image guidance for TIPS creation, equivalent in efficacy to conventional fluoroscopic guidance. Real-time sonographic guidance with intravascular US may prove advantageous for cases in which there is PV thrombus, distorted anatomy, Budd-Chiari syndrome, or hepatic tumors. Copyright © 2012 SIR. Published by Elsevier Inc. All rights reserved.

Routine Chest Radiographs After Central Line Insertion: Mandatory Postprocedural Evaluation or Unnecessary Waste of Resources?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lucey, Brian; Varghese, Jose C.; Haslam, Philip

1999-09-15

Purpose: To study the cost and impact on patient management of the routine performance of chest radiographs in patients undergoing imaged-guided central venous catheter insertion. Methods: Six hundred and twenty-one catheters placed in 489 patients over a 42-month period formed the study group. Catheters were placed in the right internal jugular vein (425), left internal jugular vein (133), and subclavian veins (63). At the end of the procedure fluoroscopy was used to assess catheter position and check for complications. A postprocedural chest radiograph was obtained in all patients. Results: Postprocedural chest fluoroscopy showed no evidence of pneumothorax, hemothorax, or mediastinalmore » hematoma. Inappropriate catheter tip position or catheter kinks were noted with 90 catheters. These problems were all corrected while the patient was on the interventional table. Postprocedural chest radiographs showed no complications but proximal catheter tip migration was noted in six of 621 catheters (1%). These latter six catheters required further manipulation. The total technical and related charges for the postprocedural chest radiographs in this series were estimated at Pounds 15,525. Conclusion: Postprocedural chest radiographs after image-guided central venous catheter insertion are not routinely required. A postprocedural chest radiograph can be performed on a case-by-case basis at the discretion of the interventional radiologist.« less

Efficacy comparison between cryoablation and radiofrequency ablation for patients with cavotricuspid valve isthmus dependent atrial flutter: a meta-analysis

NASA Astrophysics Data System (ADS)

Chen, Yi-He; Lin, Hui; Xie, Cheng-Long; Zhang, Xiao-Ting; Li, Yi-Gang

2015-06-01

We perform this meta-analysis to compare the efficacy and safety of cryoablation versus radiofrequency ablation for patients with cavotricuspid valve isthmus dependent atrial flutter. By searching EMBASE, MEDLINE, PubMed and Cochrane electronic databases from March 1986 to September 2014, 7 randomized clinical trials were included. Acute (risk ratio[RR]: 0.93; P = 0.14) and long-term (RR: 0.94; P = 0.08) success rate were slightly lower in cryoablation group than in radiofrequency ablation group, but the difference was not statistically significant. Additionally, the fluoroscopy time was nonsignificantly reduced (weighted mean difference[WMD]: -2.83 P = 0.29), whereas procedure time was significantly longer (WMD: 25.95; P = 0.01) in cryoablation group compared with radiofrequency ablation group. Furthermore, Pain perception during the catheter ablation was substantially less in cryoabaltion group than in radiofrequency ablation group (standardized mean difference[SMD]: -2.36 P < 0.00001). Thus, our meta-analysis demonstrated that cryoablation and radiofrequency ablation produce comparable acute and long-term success rate for patients with cavotricuspid valve isthmus dependent atrial flutter. Meanwhile, cryoablation ablation tends to reduce the fluoroscopy time and significantly reduce pain perception in cost of significantly prolonged procedure time.

Efficacy comparison between cryoablation and radiofrequency ablation for patients with cavotricuspid valve isthmus dependent atrial flutter: a meta-analysis

PubMed Central

Chen, Yi-He; Lin, Hui; Xie, Cheng-Long; Zhang, Xiao-Ting; Li, Yi-Gang

2015-01-01

We perform this meta-analysis to compare the efficacy and safety of cryoablation versus radiofrequency ablation for patients with cavotricuspid valve isthmus dependent atrial flutter. By searching EMBASE, MEDLINE, PubMed and Cochrane electronic databases from March 1986 to September 2014, 7 randomized clinical trials were included. Acute (risk ratio[RR]: 0.93; P = 0.14) and long-term (RR: 0.94; P = 0.08) success rate were slightly lower in cryoablation group than in radiofrequency ablation group, but the difference was not statistically significant. Additionally, the fluoroscopy time was nonsignificantly reduced (weighted mean difference[WMD]: −2.83; P = 0.29), whereas procedure time was significantly longer (WMD: 25.95; P = 0.01) in cryoablation group compared with radiofrequency ablation group. Furthermore, Pain perception during the catheter ablation was substantially less in cryoabaltion group than in radiofrequency ablation group (standardized mean difference[SMD]: −2.36; P < 0.00001). Thus, our meta-analysis demonstrated that cryoablation and radiofrequency ablation produce comparable acute and long-term success rate for patients with cavotricuspid valve isthmus dependent atrial flutter. Meanwhile, cryoablation ablation tends to reduce the fluoroscopy time and significantly reduce pain perception in cost of significantly prolonged procedure time. PMID:26039980

Cervical spinal motion during intubation: efficacy of stabilization maneuvers in the setting of complete segmental instability.

PubMed

Lennarson, P J; Smith, D W; Sawin, P D; Todd, M M; Sato, Y; Traynelis, V C

2001-04-01

The purpose of this study was to characterize and compare segmental cervical motion during orotracheal intubation in cadavers with and without a complete subaxial injury, as well as to examine the efficacy of commonly used stabilization techniques in limiting that motion. Intubation procedures were performed in 10 fresh human cadavers in which cervical spines were intact and following the creation of a complete C4-5 ligamentous injury. Movement of the cervical spine during direct laryngoscopy and intubation was recorded using video fluoroscopy and examined under the following conditions: 1) without stabilization; 2) with manual in-line cervical immobilization; and 3) with Gardner-Wells traction. Subsequently, segmental angular rotation, subluxation, and distraction at the injured C4-5 level were measured from digitized frames of the recorded video fluoroscopy. After complete C4-5 destabilization, the effects of attempted stabilization on distraction, angulation, and subluxation were analyzed. Immobilization effectively eliminated distraction, and diminished angulation, but increased subluxation. Traction significantly increased distraction, but decreased angular rotation and effectively eliminated subluxation. Orotracheal intubation without stabilization had intermediate results, causing less distraction than traction, less subluxation than immobilization, but increased angulation compared with either intervention. These results are discussed in terms of both statistical and clinical significance and recommendations are made.

Accuracy of pedicle screw placement comparing robot-assisted technology and the free-hand with fluoroscopy-guided method in spine surgery: An updated meta-analysis.

PubMed

Fan, Yong; Du, Jin Peng; Liu, Ji Jun; Zhang, Jia Nan; Qiao, Huan Huan; Liu, Shi Chang; Hao, Ding Jun

2018-06-01

A miniature spine-mounted robot has recently been introduced to further improve the accuracy of pedicle screw placement in spine surgery. However, the differences in accuracy between the robotic-assisted (RA) technique and the free-hand with fluoroscopy-guided (FH) method for pedicle screw placement are controversial. A meta-analysis was conducted to focus on this problem. Several randomized controlled trials (RCTs) and cohort studies involving RA and FH and published before January 2017 were searched for using the Cochrane Library, Ovid, Web of Science, PubMed, and EMBASE databases. A total of 55 papers were selected. After the full-text assessment, 45 clinical trials were excluded. The final meta-analysis included 10 articles. The accuracy of pedicle screw placement within the RA group was significantly greater than the accuracy within the FH group (odds ratio 95%, "perfect accuracy" confidence interval: 1.38-2.07, P < .01; odds ratio 95% "clinically acceptable" Confidence Interval: 1.17-2.08, P < .01). There are significant differences in accuracy between RA surgery and FH surgery. It was demonstrated that the RA technique is superior to the conventional method in terms of the accuracy of pedicle screw placement.

A biplanar fluoroscopic approach for the measurement, modeling, and simulation of needle and soft-tissue interaction.

PubMed

Hing, James T; Brooks, Ari D; Desai, Jaydev P

2007-02-01

A methodology for modeling the needle and soft-tissue interaction during needle insertion is presented. The approach consists of the measurement of needle and tissue motion using a dual C-arm fluoroscopy system. Our dual C-arm fluoroscopy setup allows real time 3-D extraction of the displacement of implanted fiducials in the soft tissue during needle insertion to obtain the necessary parameters for accurate modeling of needle and soft-tissue interactions. The needle and implanted markers in the tissue are tracked during the insertion and withdrawal of the needle at speeds of 1.016 mm/s, 12.7 mm/s and 25.4 mm/s. Both image and force data are utilized to determine important parameters such as the approximate cutting force, puncture force, the local effective modulus (LEM) during puncture, and the relaxation of tissue. We have also validated the LEM computed from our finite element model with arbitrary needle puncture tasks. Based on these measurements, we developed a model for needle insertion and withdrawal that can be used to generate a 1-DOF force versus position profile that can be experienced by a user operating a haptic device. This profile was implemented on a 7-DOf haptic device designed in our laboratory.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matsui, Yusuke, E-mail: wckyh140@yahoo.co.jp; Hiraki, Takao, E-mail: takaoh@tc4.so-net.ne.jp; Gobara, Hideo, E-mail: gobara@cc.okayama-u.ac.jp

IntroductionComputed tomography (CT) fluoroscopy-guided renal cryoablation and lung radiofrequency ablation (RFA) have received increasing attention as promising cancer therapies. Although radiation exposure of interventional radiologists during these procedures is an important concern, data on operator exposure are lacking.Materials and MethodsRadiation dose to interventional radiologists during CT fluoroscopy-guided renal cryoablation (n = 20) and lung RFA (n = 20) was measured prospectively in a clinical setting. Effective dose to the operator was calculated from the 1-cm dose equivalent measured on the neck outside the lead apron, and on the left chest inside the lead apron, using electronic dosimeters. Equivalent dose to the operator’s finger skinmore » was measured using thermoluminescent dosimeter rings.ResultsThe mean (median) effective dose to the operator per procedure was 6.05 (4.52) μSv during renal cryoablation and 0.74 (0.55) μSv during lung RFA. The mean (median) equivalent dose to the operator’s finger skin per procedure was 2.1 (2.1) mSv during renal cryoablation, and 0.3 (0.3) mSv during lung RFA.ConclusionRadiation dose to interventional radiologists during renal cryoablation and lung RFA were at an acceptable level, and in line with recommended dose limits for occupational radiation exposure.« less

Robotic navigation and ablation.

PubMed

Malcolme-Lawes, L; Kanagaratnam, P

2010-12-01

Robotic technologies have been developed to allow optimal catheter stability and reproducible catheter movements with the aim of achieving contiguous and transmural lesion delivery. Two systems for remote navigation of catheters within the heart have been developed; the first is based on a magnetic navigation system (MNS) Niobe, Stereotaxis, Saint-Louis, Missouri, USA, the second is based on a steerable sheath system (Sensei, Hansen Medical, Mountain View, CA, USA). Both robotic and magnetic navigation systems have proven to be feasible for performing ablation of both simple and complex arrhythmias, particularly atrial fibrillation. Studies to date have shown similar success rates for AF ablation compared to that of manual ablation, with many groups finding a reduction in fluoroscopy times. However, the early learning curve of cases demonstrated longer procedure times, mainly due to additional setup times. With centres performing increasing numbers of robotic ablations and the introduction of a pressure monitoring system, lower power settings and instinctive driving software, complication rates are reducing, and fluoroscopy times have been lower than manual ablation in many studies. As the demand for catheter ablation for arrhythmias such as atrial fibrillation increases and the number of centres performing these ablations increases, the demand for systems which reduce the hand skill requirement and improve the comfort of the operator will also increase.

Fluoroscopy-guided hydrostatic reduction of intussusception in infancy: role of pharmacological premedication.

PubMed

Esposito, Francesco; Ambrosio, Concetta; De Fronzo, Simona; Panico, Maria Rita; D'Aprano, Marilena; Giugliano, Anna Marcella; Noviello, Domenico; Oresta, Patrizia

2015-06-01

Intussusception is one of the most common causes of paediatric emergency. Fluoroscopy-guided hydrostatic reduction is a common nonoperative management strategy for the treatment of intussusception. The role of pharmacological premedication in increasing the success rate of hydrostatic reduction is still controversial. The purpose of this study was to verify the presence of a possible correlation between pharmacological premedication and the percentage of hydrostatic reduction of intussusception in paediatric patients. This study considered children with a diagnosis of idiopathic intussusception treated at our hospital between January 2007 and June 2013. One group of patients underwent hydrostatic reduction by barium enema without any preliminary therapy. A second group of patients received pharmacological premedication with both a sedative and an anti-oedematous agent before the procedure. A total of 398 patients were treated with barium enema for therapeutic purposes. In the group of patients who received no premedication (n = 254), 165 (65 %) children achieved hydrostatic reduction of the intussusception. Among the patients who received pharmacological premedication prior to barium enema (n = 144), 122 (85 %) children achieved resolution of the intussusception. Our study shows that the use of pharmacological premedication is effective for the reduction of the intussusception, as its limit patient stress, fluoroscopic time and radiation dose.

Temporal response improvement for computed tomography fluoroscopy

NASA Astrophysics Data System (ADS)

Hsieh, Jiang

1997-10-01

Computed tomography fluoroscopy (CTF) has attracted significant attention recently. This is mainly due to the growing clinical application of CTF in interventional procedures, such as guided biopsy. Although many studies have been conducted for its clinical efficacy, little attention has been paid to the temporal response and the inherent limitations of the CTF system. For example, during a biopsy operation, when needle is inserted at a relatively high speed, the true needle position will not be correctly depicted in the CTF image due to the time delay. This could result in an overshoot or misplacement of the biopsy needle by the operator. In this paper, we first perform a detailed analysis of the temporal response of the CTF by deriving a set of equations to describe the average location of a moving object observed by the CTF system. The accuracy of the equations is verified by computer simulations and experiments. We show that the CT reconstruction process acts as a low pass filter to the motion function. As a result, there is an inherent time delay in the CTF process to the true biopsy needle motion and locations. Based on this study, we propose a generalized underscan weighting scheme which significantly improve the performance of CTF in terms of time lag and delay.

On-line data collection platform for national dose surveys in diagnostic and interventional radiology.

PubMed

Vassileva, J; Simeonov, F; Avramova-Cholakova, S

2015-07-01

According to the Bulgarian regulation for radiation protection at medical exposure, the National Centre of Radiobiology and Radiation Protection (NCRRP) is responsible for performing national dose surveys in diagnostic and interventional radiology and nuclear medicine and for establishing of national diagnostic reference levels (DRLs). The next national dose survey is under preparation to be performed in the period of 2015-16, with the aim to cover conventional radiography, mammography, conventional fluoroscopy, interventional and fluoroscopy guided procedures and CT. It will be performed electronically using centralised on-line data collection platform established by the NCRRP. The aim is to increase the response rate and to improve the accuracy by reducing human errors. The concept of the on-line dose data collection platform is presented. Radiological facilities are provided with a tool to determine local typical patient doses, and the NCRRP to establish national DRLs. Future work will include automatic retrieval of dose data from hospital picture archival and communicating system. The on-line data collection platform is expected to facilitate the process of dose audit and optimisation of radiological procedures in Bulgarian hospitals. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

[Measurement of screw length through drilling technique in osteosynthesis of the proximal humerus fractures].

PubMed

Avcı, Cem Coşkun; Gülabi, Deniz; Sağlam, Necdet; Kurtulmuş, Tuhan; Saka, Gürsel

2013-01-01

This study aims to investigate the efficacy of screw length measurement through drilling technique on the reduction of intraarticular screw penetration and fluoroscopy time in osteosynthesis of proximal humerus fractures. Between January 2008 and June 2012, 98 patients (34 males, 64 females; mean age 64.4 years; range 35 to 81 years) who underwent osteosynthesis using locking anatomical proximal humerus plates (PHILOS) in our clinic with the diagnosis of Neer type 2, 3 or 4 were included. Two different surgical techniques were used to measure proximal screw length in the plate and patients were divided into two groups based on the technique used. In group 1, screw length was determined by a 3 mm blunt tipped Kirschner wire without fluoroscopic control. In group 2, bilateral fluoroscopic images for each screw at least were obtained. Intraarticular screw penetration was detected in five patients (10.6%) in group 1, and in 19 patients (37.3%) in group 2. The mean fluoroscopic imaging time was 10.6 seconds in group 1 and 24.8 seconds in group 2, indicating a statistically significant difference. Screw length measurement through the drilling technique significantly reduces the intraarticular screw penetration and fluoroscopy time in osteosynthesis of proximal humerus fractures using PHILOS plates.

Incremental benefit of 3D transesophageal echocardiography: a case of a mass overlying a prosthetic mitral valve.

PubMed

Tauras, James M; Zhang, Zhihang; Taub, Cynthia C

2011-05-01

A young woman with a mechanical mitral valve and prosthetic mitral stenosis underwent multiple imaging modalities (including transthoracic ECHO, fluoroscopy, and two-dimensional transesophageal ECHO) to determine the cause of her stenosis. Only three-dimensional transesophageal echocardiography demonstrated the full size and extent of an obstructing mass on the strut and sewing ring of the prosthetic mitral valve. © 2011, Wiley Periodicals, Inc.

Accessory pathway ablation in a 6-year-old girl using remote magnetic navigation as an alternative to cryoablation.

PubMed

Mantziari, Lilian; Rigby, Michael; Till, Janice; Ernst, Sabine

2013-03-01

A 6-year-old girl with evidence of a parahisian accessory pathway on a baseline electrocardiogram underwent successful catheter ablation using magnetic navigation. Magnetic remote controlled ablation eliminated the parahisian pathway with the first radiofrequency application. A second anterolaterally located concealed pathway was successfully ablated in the same session, resulting in exclusively atrioventricular nodal conduction bidirectionally (total fluoroscopy, 4 min; 25 μGy).

Pressure-Guided Positioning of Bicaval Dual-Lumen Catheters for Venovenous Extracorporeal Gas Exchange

DTIC Science & Technology

2013-01-01

inferior venae cavae , pumped through a respiratory mem- brane, and returned into the right atrium . The insertion of these cathe- ters is...sheath and advanced through the superior vena cava and the right atrium into the inferior vena cava . Correct position was confirmed via fluoroscopy...these catheters, blood is drained from the superior and inferior venae cavae through two dedicated ports and is pumped through a respiratory

Technical Note: Thoracic duct embolization for treatment of chylothorax: A novel guidance technique for puncture using combined MRI and fluoroscopy

PubMed Central

Praveen, Alampath; Sreekumar, Karumathil Pullara; Nazar, Puthukudiyil Kader; Moorthy, Srikanth

2012-01-01

Thoracic duct embolization (TDE) is an established radiological interventional procedure for thoracic duct injuries. Traditionally, it is done under fluoroscopic guidance after opacifying the thoracic duct with bipedal lymphangiography. We describe our experience in usinga heavily T2W sequence for guiding thoracic duct puncture and direct injection of glue through the puncture needle without cannulating the duct. PMID:23162248

Can We Improve Workflows in the OR? A Comparison of Quality Perceptions and Preoperative Efficiency across Institutions in Spine Surgery.

PubMed

Wasterlain, Amy S; Tran, Andrew A; Tang, Chad; Campbell, David R; Braun, Hillary J; Scuderi, Yasmeen A; Scuderi, Gaetano J

2015-03-01

Cost containment and surgical inefficiencies are major concerns for hospitals in this era of declining resources. The primary aim of this investigation was to understand subjective perceptions of perioperative spine surgical quality across three practice settings and to identify potential factors contributing to these perceptions. Subsequently, we objectively evaluated factors that influence the duration of time in which the patient is in the operating room (OR) prior to the surgical incision and assessed the influence of fluoroscopy technician expertise on radiation dose and imaging efficiency. One hundred and eight medical device representatives with at least 1 year of OR experience were surveyed at a national conference. Three distinct healthcare facilities were identified: university, small volume, and large volume private hospitals. Respondents rated facilities on a five-point scale for staff quality; size and consistency of surgical teams; and overall likelihood of recommending the facility. Separately, 140 posterior lumbar procedures from two institutions were retrospectively reviewed. Two time periods were quantified for each surgical case: patient arrival in the OR to induction of anesthesia (T1) and induction to surgical incision (T2). T1 and T2 were compared between university and large private hospital settings using t tests and multivariate analysis. For 44 separate lumbar spine surgical procedures, practice setting, patient BMI, number of vertebral levels requiring imaging, number of localizing fluoroscopy images taken, total fluoroscopy time, total radiation dose, fluoroscopy machine, and whether the fluoroscopist could correctly state his or her role, which was to obtain a lateral lumbar localizing image, were recorded. T-tests were used to compare cases in which the fluoroscopist could and could not correctly state the task. Survey ratings for surgeons were not significantly different across university, large private, and small private hospitals. Fewer circulating nurses were rated as excellent or good in university versus private hospitals (p < 0.001). Small volume private hospital surgical teams were more likely to have worked together before than university teams (p < 0.05), and university teams were larger (p < 0.05). Respondents were more likely to recommend a university or large private hospital for complex instrumentation cases (p < 0.001). On objective measures, university patients were older, less obese, and had higher mean ASA scores (2.5 versus 2.2, p < 0.001). Compared to the university setting, private hospital cases had significantly shorter Time 1 (8 versus 37 min, p < 0.001) and Time 2 (23 versus 30 min, p < 0.001), even after adjusting for ASA score, BMI, and age. Cases in which the fluoroscopist knew the imaging purpose were associated with significantly fewer images (mean 1.8 versus 3.4 images, p < 0.0001) and shorter total exposure times (2.3 versus 4.0 sec, p < 0.001). Operations performed in the university setting were associated with significantly more images (2.7 versus 1.8 images, p < 0.001), longer total exposure times (3.2 versus 2.3 sec, p = 0.0027), and total radiation dose (27.8 versus 53.3 rad, p < 0.001) when compared with those performed in the private setting. The university practice setting was associated with significantly more images (2.7 versus 1.8 images, p < 0.001), longer total exposure times (3.2 versus 2.3 sec, p = 0.003), and total radiation dose (27.8 versus 53.3 rad, p < 0.001) when compared with non-university settings. Large private and university hospitals had higher surgeon ratings. The university setting was associated with larger and less consistent surgical teams and lower nurse ratings. Surgical staff awareness of the procedure and attention to preoperative tasks specific to the procedure reduced pre-operative time spent in the OR as well as fluoroscopy radiation. These data suggest that nurses and support staff make substantial contributions to overall quality of care, and that leadership and interpersonal coordination are especially important within large teams at teaching hospitals.

Radiation Awareness for Endovascular Abdominal Aortic Aneurysm Repair in the Hybrid Operating Room. An Instant Patient Risk Chart for Daily Practice.

PubMed

de Ruiter, Quirina M; Gijsberts, Crystel M; Hazenberg, Constantijn E; Moll, Frans L; van Herwaarden, Joost A

2017-06-01

To determine which patient and C-arm characteristics are the strongest predictors of intraoperative patient radiation dose rates (DRs) during endovascular aneurysm repair (EVAR) procedures and create a patient risk chart. A retrospective analysis was performed of 74 EVAR procedures, including 16,889 X-ray runs using fixed C-arm imaging equipment. Four multivariate log-linear mixed models (with patient as a random effect) were constructed. Mean air kerma DR (DR AK , mGy/s) and the mean dose area product DR (DR DAP , mGycm 2 /s) were the outcome variables utilized for fluoroscopy as differentiated from digital subtraction angiography (DSA). These models were used to predict the maximum radiation duration allowed before a 2-Gy skin threshold (for DR AK ) or a 500-Gycm 2 threshold (for DR DAP ) was reached. The strongest predictor of DR AK and DR DAP for fluoroscopy imaging was the radiation protocol, with an increase of 200% when changing from "low" to "medium" and 410% from "low" to "normal." The strongest predictors of DR AK and DR DAP for DSA were C-arm angulation, with an increase of 47% per 30° of angulation, and body mass index (BMI), with an increase of 58% for every 5-point increase in BMI. Based on these models, a patient with a BMI of 30 kg/m 2 , combined with 45° of rotation and a field size of 800 cm 2 in the medium fluoroscopy protocol has a predicted DR AK of 0.39 mGy/s (or 85.5 minutes until the 2-Gy skin threshold is reached). While using comparable settings but switching the acquisition to a DSA with a "2 frames per second" protocol, the predicted DR AK will be 6.6 mGy/s (or 5.0 minutes until the 2-Gy threshold is reached). X-ray radiation DRs are constantly fluctuating during and between patients based on BMI, the protocols, C-arm position, and the image acquisitions that are used. An instant patient risk chart visualizes these radiation dose fluctuations and provides an overview of the expected duration of X-ray radiation, which can be used to predict when follow-up dose thresholds are reached during abdominal endovascular procedures.

Endovascular aneurysm repair simulation can lead to decreased fluoroscopy time and accurately delineate the proximal seal zone.

PubMed

Kim, Ann H; Kendrick, Daniel E; Moorehead, Pamela A; Nagavalli, Anil; Miller, Claire P; Liu, Nathaniel T; Wang, John C; Kashyap, Vikram S

2016-07-01

The use of simulators for endovascular aneurysm repair (EVAR) is not widespread. We examined whether simulation could improve procedural variables, including operative time and optimizing proximal seal. For the latter, we compared suprarenal vs infrarenal fixation endografts, right femoral vs left femoral main body access, and increasing angulation of the proximal aortic neck. Computed tomography angiography was obtained from 18 patients who underwent EVAR at a single institution. Patient cases were uploaded to the ANGIO Mentor endovascular simulator (Simbionix, Cleveland, Ohio) allowing for three-dimensional reconstruction and adapted for simulation with suprarenal fixation (Endurant II; Medtronic Inc, Minneapolis, Minn) and infrarenal fixation (C3; W. L. Gore & Associates Inc, Newark, Del) deployment systems. Three EVAR novices and three experienced surgeons performed 18 cases from each side with each device in randomized order (n = 72 simulations/participant). The cases were stratified into three groups according to the degree of infrarenal angulation: 0° to 20°, 21° to 40°, and 41° to 66°. Statistical analysis used paired t-test and one-way analysis of variance. Mean fluoroscopy time for participants decreased by 48.6% (P < .0001), and total procedure time decreased by 33.8% (P < .0001) when initial cases were compared with final cases. When stent deployment accuracy was evaluated across all cases, seal zone coverage in highly angulated aortic necks was significantly decreased. The infrarenal device resulted in mean aortic neck zone coverage of 91.9%, 89.4%, and 75.4% (P < .0001 by one-way analysis of variance), whereas the suprarenal device yielded 92.9%, 88.7%, and 71.5% (P < .0001) for the 0° to 20°, 21° to 40°, and 41° to 66° cases, respectively. Suprarenal fixation did not increase seal zone coverage. The side of femoral access for the main body did not influence proximal seal zone coverage regardless of infrarenal angulation. Simulation of EVAR leads to decreased fluoroscopy times for novice and experienced operators. Side of femoral access did not affect precision of proximal endograft landing. The angulated aortic neck leads to decreased proximal seal zone coverage regardless of infrarenal or suprarenal fixation devices. Copyright © 2016 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

Evaluation of a new very low dose imaging protocol: feasibility and impact on X-ray dose levels in electrophysiology procedures.

PubMed

Bourier, Felix; Reents, Tilko; Ammar-Busch, Sonia; Buiatti, Alessandra; Kottmaier, Marc; Semmler, Verena; Telishevska, Marta; Brkic, Amir; Grebmer, Christian; Lennerz, Carsten; Kolb, Christof; Hessling, Gabriele; Deisenhofer, Isabel

2016-09-01

This study presents and evaluates the impact of a new lowest-dose fluoroscopy protocol (Siemens AG), especially designed for electrophysiology (EP) procedures, on X-ray dose levels. From October 2014 to March 2015, 140 patients underwent an EP study on an Artis zee angiography system. The standard low-dose protocol was operated at 23 nGy (fluoroscopy) and at 120 nGy (cine-loop), the new lowest-dose protocol was operated at 8 nGy (fluoroscopy) and at 36 nGy (cine-loop). Procedural data, X-ray times, and doses were analysed in 100 complex left atrial and in 40 standard EP procedures. The resulting dose-area products were 877.9 ± 624.7 µGym² (n = 50 complex procedures, standard low dose), 199 ± 159.6 µGym² (n = 50 complex procedures, lowest dose), 387.7 ± 36.0 µGym² (n = 20 standard procedures, standard low dose), and 90.7 ± 62.3 µGym² (n = 20 standard procedures, lowest dose), P < 0.01. In the low-dose and lowest-dose groups, procedure times were 132.6 ± 35.7 vs. 126.7 ± 34.7 min (P = 0.40, complex procedures) and 72.3 ± 20.9 vs. 85.2 ± 44.1 min (P = 0.24, standard procedures), radiofrequency (RF) times were 53.8 ± 26.1 vs. 50.4 ± 29.4 min (P = 0.54, complex procedures) and 10.1 ± 9.9 vs. 12.2 ± 14.7 min (P = 0.60, standard procedures). One complication occurred in the standard low-dose and lowest-dose groups (P = 1.0). The new lowest-dose imaging protocol reduces X-ray dose levels by 77% compared with the currently available standard low-dose protocol. From an operator standpoint, lowest X-ray dose levels create a different, reduced image quality. The new image quality did not significantly affect procedure or RF times and did not result in higher complication rates. Regarding radiological protection, operating at lowest-dose settings should become standard in EP procedures. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.

Robust 3D-2D image registration: application to spine interventions and vertebral labeling in the presence of anatomical deformation

NASA Astrophysics Data System (ADS)

Otake, Yoshito; Wang, Adam S.; Webster Stayman, J.; Uneri, Ali; Kleinszig, Gerhard; Vogt, Sebastian; Khanna, A. Jay; Gokaslan, Ziya L.; Siewerdsen, Jeffrey H.

2013-12-01

We present a framework for robustly estimating registration between a 3D volume image and a 2D projection image and evaluate its precision and robustness in spine interventions for vertebral localization in the presence of anatomical deformation. The framework employs a normalized gradient information similarity metric and multi-start covariance matrix adaptation evolution strategy optimization with local-restarts, which provided improved robustness against deformation and content mismatch. The parallelized implementation allowed orders-of-magnitude acceleration in computation time and improved the robustness of registration via multi-start global optimization. Experiments involved a cadaver specimen and two CT datasets (supine and prone) and 36 C-arm fluoroscopy images acquired with the specimen in four positions (supine, prone, supine with lordosis, prone with kyphosis), three regions (thoracic, abdominal, and lumbar), and three levels of geometric magnification (1.7, 2.0, 2.4). Registration accuracy was evaluated in terms of projection distance error (PDE) between the estimated and true target points in the projection image, including 14 400 random trials (200 trials on the 72 registration scenarios) with initialization error up to ±200 mm and ±10°. The resulting median PDE was better than 0.1 mm in all cases, depending somewhat on the resolution of input CT and fluoroscopy images. The cadaver experiments illustrated the tradeoff between robustness and computation time, yielding a success rate of 99.993% in vertebral labeling (with ‘success’ defined as PDE <5 mm) using 1,718 664 ± 96 582 function evaluations computed in 54.0 ± 3.5 s on a mid-range GPU (nVidia, GeForce GTX690). Parameters yielding a faster search (e.g., fewer multi-starts) reduced robustness under conditions of large deformation and poor initialization (99.535% success for the same data registered in 13.1 s), but given good initialization (e.g., ±5 mm, assuming a robust initial run) the same registration could be solved with 99.993% success in 6.3 s. The ability to register CT to fluoroscopy in a manner robust to patient deformation could be valuable in applications such as radiation therapy, interventional radiology, and an assistant to target localization (e.g., vertebral labeling) in image-guided spine surgery.

Isocentric Navigation of Percutaneous Endoscopic Transforaminal Discectomy at the L5/S1 Level in Difficult Puncture Cases: A Technical Note.

PubMed

Fan, Guoxin; Wang, Teng; Hu, Shuo; Guan, Xiaofei; Gu, Xin; He, Shisheng

2017-05-01

Accurate puncture during percutaneous transforaminal endoscopic discectomy at the L5/S1 level in cases with high iliac crest and narrow foramen were difficult, even though the difficulties of foraminoplasty could be overcome by advanced instruments like reamers. The report aimed to describe an isocentric navigation technique with a definite pathway in difficult puncture cases at the L5/S1 level. Technical note. Difficult punctures were defined as over 10 punctures of the needle before obtaining an ideal puncture location by senior surgeons with experience of over 500 percutaneous endoscopic transforaminal discectomy (PETD) cases. A total of 124 punctures were recorded in 11 difficult puncture cases at the L5/S1 level. A definite pathway was created by an isocentric navigation theory, which was based on a surface locator and an arch-guided device. The surface locator was used to rapidly and accurately identify the puncture target with the recognition of the surrounding rods under fluoroscopy. The arch-guided device can ensure that the puncture target always remains at the center of a virtual sphere. We recorded the puncture times, fluoroscopy exposure times, radiation exposure time, operative time, visual analog scale (VAS) score, Japanese Orthopeadic Association (JOA) score, and patient satisfaction. The average puncture times were significantly reduced to 1.27 with the arch-guided device compared with conventional puncture methods (P < 0.05). The average operative time was 90.09 ± 11.00 minutes and the fluoroscopy times were 53.36 ± 5.85. The radiation exposure time was 50.91 ± 5.20 seconds. VAS score of leg and back pain, as well as JOA score, were all significantly improved after surgery (P < 0.05). The excellent and good rate of satisfaction was 90.91%. No major complications, including cerebral fluid leakage, surgical infection, and postoperative nerve root injury, were recorded in this small sample. This was a small-sample study with a short follow-up. The novel isocentric navigation technique with a definite pathway is practical and effective in reducing puncture times among difficult puncture cases at the L5/S1 level, which may contribute to the capacity of PETD at the L5/S1 level.

Electromagnetic Real Time Navigation in the Region of the Posterior Pelvic Ring: An Experimental In-Vitro Feasibility Study and Comparison of Image Guided Techniques.

PubMed

Pishnamaz, Miguel; Wilkmann, Christoph; Na, Hong-Sik; Pfeffer, Jochen; Hänisch, Christoph; Janssen, Max; Bruners, Philipp; Kobbe, Philipp; Hildebrand, Frank; Schmitz-Rode, Thomas; Pape, Hans-Christoph

2016-01-01

Electromagnetic tracking is a relatively new technique that allows real time navigation in the absence of radiation. The aim of this study was to prove the feasibility of this technique for the treatment of posterior pelvic ring fractures and to compare the results with established image guided procedures. Tests were performed in pelvic specimens (Sawbones®) with standardized sacral fractures (Type Denis I or II). A gel matrix simulated the operative approach and a cover was used to disable visual control. The electromagnetic setup was performed by using a custom made carbon reference plate and a prototype stainless steel K-wire with an integrated sensor coil. Four different test series were performed: Group OCT: Optical navigation using preoperative CT-scans; group O3D: Optical navigation using intraoperative 3-D-fluoroscopy; group Fluoro: Conventional 2-D-fluoroscopy; group EMT: Electromagnetic navigation combined with a preoperative Dyna-CT. Accuracy of screw placement was analyzed by standardized postoperative CT-scan for each specimen. Operation time and intraoperative radiation exposure for the surgeon was documented. All data was analyzed using SPSS (Version 20, 76 Chicago, IL, USA). Statistical significance was defined as p< 0.05. 160 iliosacral screws were placed (40 per group). EMT resulted in a significantly higher incidence of optimal screw placement (EMT: 36/40) compared to the groups Fluoro (30/40; p< 0.05) and OCT (31/40; p< 0.05). Results between EMT and O3D were comparable (O3D: 37/40; n.s.). Also, the operation time was comparable between groups EMT and O3D (EMT 7.62 min vs. O3D 7.98 min; n.s.), while the surgical time was significantly shorter compared to the Fluoro group (10.69 min; p< 0.001) and the OCT group (13.3 min; p< 0.001). Electromagnetic guided iliosacral screw placement is a feasible procedure. In our experimental setup, this method was associated with improved accuracy of screw placement and shorter operation time when compared with the conventional fluoroscopy guided technique and compared to the optical navigation using preoperative CT-scans. Further studies are necessary to rule out drawbacks of this technique regarding ferromagnetic objects.

Multimodality imaging of adult gastric emergencies: A pictorial review

PubMed Central

Sunnapwar, Abhijit; Ojili, Vijayanadh; Katre, Rashmi; Shah, Hardik; Nagar, Arpit

2017-01-01

Acute gastric emergencies require urgent surgical or nonsurgical intervention because they are associated with high morbidity and mortality. Imaging plays an important role in diagnosis since the clinical symptoms are often nonspecific and radiologist may be the first one to suggest a diagnosis as the imaging findings are often characteristic. The purpose of this article is to provide a comprehensive review of multimodality imaging (plain radiograph, fluoroscopy, and computed tomography) of various life threatening gastric emergencies. PMID:28515579

Retrieval of detached fragment of central venous pressure catheter (CVP) lodged in the right ventricle and pulmonary artery: a case report.

PubMed

Sakijan, A S; Zambahari, R; Annuar, Z; Yahya, O; Ali, J

1990-12-01

A successful retrieval of a detached segment of a CVP catheter by percutaneous right transfemoral venous route, using a Dotter intravascular retriever basket, is reported. The procedure was monitored under fluoroscopy. Only local anaesthesia, which was infiltrated around the puncture site, was given to the patient. No significant complication was encountered. Successful retrieval of the detached catheter fragment by percutaneous means obviates the need for thoracotomy.

Left Ventricular, Systemic Arterial and Baroreflex Responses to Ketamine and TEE in Chronically Instrumented Monkeys

DTIC Science & Technology

2001-12-01

instrumented with a high fidelity, dual-sensor micromanometer to measure left ventricular and aortic pressure and a transit-time ultrasound probe to...isoflurane in 100% oxy- gen) prior to insertion of the high -fidelity pressure micromanome- ters during cardiac fluoroscopy. Once the micromanometer trans...and allowed to fully recover from the isoflurane seda- tion for a period of 60 min, during which blood pressure and aortic flow were monitored to ensure

Radiopaque Marker Addition During Aortic Root Replacement With the Use of a Freestyle Porcine Bioprosthesis.

PubMed

Crowley, Olivia M; Doty, John R

2017-07-01

Aortic root replacement is indicated for aortic root aneurysm, small aortic root, and most root abscesses. This report describes the placement of a radiopaque marker during aortic root replacement using a Freestyle porcine bioprosthesis. This marker is a useful landmark during fluoroscopy for transcatheter valve-in-valve aortic valve replacement in the event of bioprosthesis degeneration. Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Novel Image-Guided Management of a Uterine Arteriovenous Malformation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Przybojewski, Stefan J., E-mail: drstefanp@hotmail.com; Sadler, David J.

The investigators present a novel image-guided embolization, not previously described, of a uterine arteriovenous malformation (AVM) resistant to endovascular management. The uterus was exposed surgically, and Histoacryl (Braun, Fulda, Germany) was injected directly into the nidus using ultrasound guidance and fluoroscopy. The patient had a successful full-term pregnancy after this procedure. This technique may be a useful alternative management strategy in patients with uterine AVM who fail traditional endovascular embolization and who still desire fertility.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ogawa, Yukihisa, E-mail: yukky.oct.22@gmail.com; Hamaguchi, Shingo; Nishimaki, Hiroshi

BackgroundEndovascular aortic repair (EVAR) requires further intervention in 20-30 % of cases, often due to type II endoleak (T2EL). Management options for T2EL include transarterial embolization, direct puncture (DP), or transcaval embolization. We report the case of an 80-year-old man with T2EL who successfully underwent DP embolization.MethodsEmbolization by DP was performed with a transpedicular approach using an isocenter puncture (ISOP) method. An isocenter marker (ICM) was placed at a site corresponding to the aneurysm sac on fluoroscopy in two directions (frontal and lateral views). A vertebroplasty needle was inserted tangentially to the ICM under fluoroscopy and advanced to the anterior wallmore » of the vertebral body. A 20 cm-length, 20-G-PTCD needle was inserted through the outer needle of the 13-G needle and advanced to the ICM. Sac embolization using 25 % N-buty-2-cyanoacrylate diluted with Lipiodol was performed. After complete embolization, rotational DA confirmed good filling of the sac with Lipiodol. The outer cannula and 13-G needle were removed and the procedure was completed.ResultsThe patient was discharged the next day. Contrast-enhanced computed tomography 1 and 8 months later showed no Lipiodol washout in the aneurysm sac, no endoleak recurrence, and no expansion of the excluded aneurysm.ConclusionDP with a transpedicular approach using ISOP may be useful when translumbar and transabdominal approaches prove difficult.« less

DQE and system optimization for indirect-detection flat-panel imagers in diagnostic radiology

NASA Astrophysics Data System (ADS)

Siewerdsen, Jeffrey H.; Antonuk, Larry E.

1998-07-01

The performance of indirect-detection flat-panel imagers incorporating CsI:Tl x-ray converters is examined through calculation of the detective quantum efficiency (DQE) under conditions of chest radiography, fluoroscopy, and mammography. Calculations are based upon a cascaded systems model which has demonstrated excellent agreement with empirical signal, noise- power spectra, and DQE results. For each application, the DQE is calculated as a function of spatial-frequency and CsI:Tl thickness. A preliminary investigation into the optimization of flat-panel imaging systems is described, wherein the x-ray converter thickness which provides optimal DQE for a given imaging task is estimated. For each application, a number of example tasks involving detection of an object of variable size and contrast against a noisy background are considered. The method described is fairly general and can be extended to account for a variety of imaging tasks. For the specific examples considered, the preliminary results estimate optimal CsI:Tl thicknesses of approximately 450 micrometer (approximately 200 mg/cm2), approximately 320 micrometer (approximately 140 mg/cm2), and approximately 200 micrometer (approximately 90 mg/cm2) for chest radiography, fluoroscopy, and mammography, respectively. These results are expected to depend upon the imaging task as well as upon the quality of available CsI:Tl, and future improvements in scintillator fabrication could result in increased optimal thickness and DQE.

Radiation exposure to the eye lens of orthopaedic surgeons during various orthopaedic procedures.

PubMed

Romanova, K; Vassileva, J; Alyakov, M

2015-07-01

The aim of the present study was to assess the radiation dose to the eye lens of orthopaedic surgeons during various orthopaedic procedures and to make efforts to ensure that radiation protection is optimised. The study was performed for Fractura femoris and Fractura cruris procedures performed in orthopaedic operating theatres, as well as for fractures of wrist, ankle and hand/shoulder performed in the emergency trauma room. The highest mean value of the eye lens dose of 47.2 μSv and higher mean fluoroscopy time of 3 min, as well as the corresponding highest maximum values of 77.1 μSv and 5.0 min were observed for the Fractura femoris procedure performed with the Biplanar 500e fluoroscopy systems. At a normal workload, the estimated mean annual dose values do not exceed the annual occupational dose limit for the lens of eye, but at a heavy workload in the department, this dose limit could be achieved or exceeded. The use of protective lead glasses is recommended as they could reduce the radiation exposure of the lens of the eye. The phantom measurements demonstrated that the use of half-dose mode could additionally reduce dose to the operator's eye lens. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Dynamic flat panel detector versus image intensifier in cardiac imaging: dose and image quality

NASA Astrophysics Data System (ADS)

Vano, E.; Geiger, B.; Schreiner, A.; Back, C.; Beissel, J.

2005-12-01

The practical aspects of the dosimetric and imaging performance of a digital x-ray system for cardiology procedures were evaluated. The system was configured with an image intensifier (II) and later upgraded to a dynamic flat panel detector (FD). Entrance surface air kerma (ESAK) to phantoms of 16, 20, 24 and 28 cm of polymethyl methacrylate (PMMA) and the image quality of a test object were measured. Images were evaluated directly on the monitor and with numerical methods (noise and signal-to-noise ratio). Information contained in the DICOM header for dosimetry audit purposes was also tested. ESAK values per frame (or kerma rate) for the most commonly used cine and fluoroscopy modes for different PMMA thicknesses and for field sizes of 17 and 23 cm for II, and 20 and 25 cm for FD, produced similar results in the evaluated system with both technologies, ranging between 19 and 589 µGy/frame (cine) and 5 and 95 mGy min-1 (fluoroscopy). Image quality for these dose settings was better for the FD version. The 'study dosimetric report' is comprehensive, and its numerical content is sufficiently accurate. There is potential in the future to set those systems with dynamic FD to lower doses than are possible in the current II versions, especially for digital cine runs, or to benefit from improved image quality.

The Usefulness of Virtual Fluoroscopic Preprocedural Planning During Percutaneous Transhepatic Biliary Drainage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kinoshita, Mitsuhiro, E-mail: kinoshita.3216@tokushima-u.ac.jp; Shirono, Ryozo; Takechi, Katsuya

Purpose To retrospectively evaluate the usefulness of virtual fluoroscopic preprocedural planning (VFPP) in the percutaneous transhepatic biliary drainage (PTBD) procedure.Materials and MethodsTwenty-two patients who were treated by PTBD were included in this study. Twelve patients were treated using PTBD intraoperative referencing coronal computed tomography (CT) images (i.e., coronal CT group), and ten patients were treated using PTBD intraoperative referencing VFPP images (i.e., VFPP group). To analyze the effect of the intraoperative referencing VFPP image, the VFPP group was retrospectively compared with the coronal CT group.ResultsThe characteristics of both patient groups were not statistically significantly different. There were no significant differencesmore » in the targeted bile duct, diameter and depth of the target bile, breath-holding ability, number of targeted bile duct puncture attempts, change in the targeted bile duct, and exchange of the drainage catheter. However, the X-ray fluoroscopy time and the procedure time were significantly shorter in the VFPP group than in the coronal CT group (196 vs. 334 s, P < 0.05; and 16.0 vs. 27.2 min, P < 0.05).ConclusionIntraoperative referencing using the VFPP imaging in PTBD intuitively can be a useful tool for better localization of the guidewire in the bile duct and thereby shorten the X-ray fluoroscopy time and procedure time while minimizing radiation exposure and complications.« less

Collection of DICOM RDSR (Digital Imaging and Communication in Medicine, Radiation Dose Structured Report) Information Aimed at Reducing Patient Exposure Dose.

PubMed

Morota, Koichi; Moritake, Takashi; Sun, Lue; Ishihara, Takahiro; Kuma, Natsuyo; Murata, Satomi; Yamada, Takahiro; Okazaki, Ryuji

2016-01-01

The recent progress in angiography technology bestows benefits on patients for minimally invasive than surgery, while there has been an increase in the number of cases involving stochastic effects, such as radiation dermatitis, resulting from upgrading of the procedure because of an extension of the time for fluoroscopy and the number of shots. Recent CT equipment saves the dose data along with image data about the information management for patient exposure dose, which is used for management of individual cumulative dose and the presumed effective dose, using digital imaging and communication in medicine (DICOM). We extracted detailed information about shooting conditions and dose from the DICOM radiation dose structured report (DICOM RDSR) in the angiography area, and evaluated the trend of patient exposure dose in each procedure. As a result, we found that cases exceeding 3 Gy which needed observation in the head region were 16.7% and in the heart region were 27.3%. We also found that angiography had a higher dose of shooting than did fluoroscopy, and that the diagnosis and treatment with tumor involvement required a exposure dose than did vascular lesion. In this paper, we review the shooting conditions as a root of DICOM RDSR information and consider the possibility of planning for further reduction of the exposure dose.

Transesophageal echocardiography and intracardiac echocardiography differently predict potential technical challenges or failures of interatrial shunts catheter-based closure.

PubMed

Rigatelli, Gianluca; Rigateli, Gianluca; Cardaioli, Paolo; Braggion, Gabriele; Aggio, Silvio; Giordan, Massimo; Magro, Beatrice; Nascimben, Alberto; Favaro, Alberto; Roncon, Loris; Rincon, Loris

2007-02-01

We sought to prospectively assess the role of transesophageal (TEE) and intracardiac echocardiography (ICE) in detecting potential technical difficulties or failures in patients submitted to interatrial shunts percutaneous closure. We prospectively enrolled 46 consecutive patients (mean age 35+/-28, 8 years, 30 female) referred to our center for catheter-based closure of interatrial shunts. All patients were screened with TEE before the intervention. Patients who met the inclusion criteria underwent ICE study before the closure attempt (40 patients). TEE detected potential technical difficulties in 22.5% (9/40) patients, whereas ICE detected technical difficulties in 32.5% (13/40 patients). In patients with positive TEE/ICE the procedural success (92.4% versus 100% and, P = ns) and follow-up failure rate (7.7% versus 0%, P = ns) were similar to patients with negative TEE/ICE, whereas the fluoroscopy time (7 +/- 1.2 versus 5 +/- 0.7 minutes, P < 0.03), the procedural time (41 +/- 4.1 versus 30 +/- 8.2 minutes, P +/- 0.03), and technical difficulties rate (23.1% versus 0%, P = 0.013) were higher. Differences between ICE and TEE in the evaluation of rims, measurement of ASD or fossa ovalis, and detection of venous valve and embryonic septal membrane remnants impacted on technical challenges and on procedural and fluoroscopy times but did not influence the success rate and follow-up failure rate.

Mini access guide to simplify calyceal access during percutaneous nephrolithotomy: A novel device.

PubMed

Chowdhury, Puskar Shyam; Nayak, Prasant; David, Deepak; Mallick, Sujata

2017-01-01

A precise puncture of the renal collecting system is the most essential step for percutaneous nephrolithotomy (PCNL). There are many techniques describing this crucial first step in PCNL including the bull's eye technique, triangulation technique, free-hand technique, and gradual descensus technique. We describe a novel puncture guide to assist accurate percutaneous needle placement during bull's eye technique. The mini access guide (MAG) stabilizes the initial puncture needle by mounting it on an adjustable multidirectional carrier fixed to the patient's skin, which aids in achieving the "bull's eye" puncture. It also avoids a direct fluoroscopic exposure of the urologist's hand during the puncture. Sixty consecutive patients with solitary renal calculus were randomized to traditional hand versus MAG puncture during bull's eye technique of puncture and the fluoroscopy time was assessed. The median fluoroscopy screening time for traditional free-hand bull's eye and MAG-guided bull's eye puncture (fluoroscopic screening time for puncture) was 55 versus 21 s ( P = 0.001) and the median time to puncture was 80 versus 55 s ( P = 0.052), respectively. Novice residents also learned puncture technique faster with MAG on simulator. The MAG is a simple, portable, cheap, and novel assistant to achieve successful PCNL puncture. It would be of great help for novices to establish access during their learning phase of PCNL. It would also be an asset toward significantly decreasing the radiation dose during PCNL access.

Navigational Guidance and Ablation Planning Tools for Interventional Radiology.

PubMed

Sánchez, Yadiel; Anvari, Arash; Samir, Anthony E; Arellano, Ronald S; Prabhakar, Anand M; Uppot, Raul N

Image-guided biopsy and ablation relies on successful identification and targeting of lesions. Currently, image-guided procedures are routinely performed under ultrasound, fluoroscopy, magnetic resonance imaging, or computed tomography (CT) guidance. However, these modalities have their limitations including inadequate visibility of the lesion, lesion or organ or patient motion, compatibility of instruments in an magnetic resonance imaging field, and, for CT and fluoroscopy cases, radiation exposure. Recent advances in technology have resulted in the development of a new generation of navigational guidance tools that can aid in targeting lesions for biopsy or ablations. These navigational guidance tools have evolved from simple hand-held trajectory guidance tools, to electronic needle visualization, to image fusion, to the development of a body global positioning system, to growth in cone-beam CT, and to ablation volume planning. These navigational systems are promising technologies that not only have the potential to improve lesion targeting (thereby increasing diagnostic yield of a biopsy or increasing success of tumor ablation) but also have the potential to decrease radiation exposure to the patient and staff, decrease procedure time, decrease the sedation requirements, and improve patient safety. The purpose of this article is to describe the challenges in current standard image-guided techniques, provide a definition and overview for these next-generation navigational devices, and describe the current limitations of these, still evolving, next-generation navigational guidance tools. Copyright © 2017 Elsevier Inc. All rights reserved.

One shot tract dilation for percutaneous nephrolithotomy: is it safe and effective in preschool children?

PubMed

Hosseini, Seyed Reza; Mohseni, Mohammad Ghasem; Alizadeh, Farshid

2014-01-01

To evaluate the safety and feasibility of percutaneous tract dilation by the one-stage method in preschool children. Between April 2009 and February 2013, all preschool (<6 years) children who were candidates for percutaneous nephrolithotomy were enrolled in this prospective study. Patients were randomly assigned to dilation by serial metallic dilators (group I, 31 patients) or dilation by one-stage Amplatz according to Frattini et al. [J Endourol 2001;15:919-923] (group II, 31 patients). The primary endpoint of interest was fluoroscopy time. Secondary endpoints included tract creation and dilation time, success rate and complications. Stone-free status was defined as residuals ≤3 mm. Age, stone size, operation success and operation time were not significantly different between the studied groups. The most common stone composition was calcium oxalate in both groups. The mean ± standard deviation of access and fluoroscopy times in groups I and II were 7.3 ± 1.2 min vs. 5.9 ± 1.5 min (p > 0.05) and 70.0 ± 8.9 s vs. 22.0 ± 5.6 s (p < 0.001), respectively. Postoperative complications included one case of postoperative fever lasting less than 48 h in group I. Percutaneous tract dilation by the one-stage method is safe and effective. Also, it is associated with considerably less radiation exposure in preschool children. © 2014 S. Karger AG, Basel.

Percutaneous CT and Fluoroscopy-Guided Screw Fixation of Pathological Fractures in the Shoulder Girdle: Technical Report of 3 Cases.

PubMed

Garnon, Julien; Koch, Guillaume; Ramamurthy, Nitin; Caudrelier, Jean; Rao, Pramod; Tsoumakidou, Georgia; Cazzato, Roberto Luigi; Gangi, Afshin

2016-09-01

To review our initial experience with percutaneous CT and fluoroscopy-guided screw fixation of pathological shoulder-girdle fractures. Between May 2014 and June 2015, three consecutive oncologic patients (mean age 65 years; range 57-75 years) with symptomatic pathological shoulder-girdle fractures unsuitable for surgery and radiotherapy underwent percutaneous image-guided screw fixation. Fractures occurred through metastases (n = 2) or a post-ablation cavity (n = 1). Mechanical properties of osteosynthesis were adjudged superior to stand-alone cementoplasty in each case. Cannulated screws were placed under combined CT and fluoroscopic guidance with complementary radiofrequency ablation or cementoplasty to optimise local palliation and secure screw fixation, respectively, in two cases. Follow-up was undertaken every few weeks until mortality or most recent appointment. Four pathological fractures were treated in three patients (2 acromion, 1 clavicular, 1 coracoid). Mean size of associated lesion was 2.6 cm (range 1-4.5 cm). Technical success was achieved in all cases (100 %), without complications. Good palliation and restoration of mobility were observed in two cases at 2-3 months; one case could not be followed due to early post-procedural oncologic mortality. Percutaneous image-guided shoulder-girdle osteosynthesis appears technically feasible with good short-term efficacy in this complex patient subset. Further studies are warranted to confirm these promising initial results.

Non-photorealistic rendering of virtual implant models for computer-assisted fluoroscopy-based surgical procedures

NASA Astrophysics Data System (ADS)

Zheng, Guoyan

2007-03-01

Surgical navigation systems visualize the positions and orientations of surgical instruments and implants as graphical overlays onto a medical image of the operated anatomy on a computer monitor. The orthopaedic surgical navigation systems could be categorized according to the image modalities that are used for the visualization of surgical action. In the so-called CT-based systems or 'surgeon-defined anatomy' based systems, where a 3D volume or surface representation of the operated anatomy could be constructed from the preoperatively acquired tomographic data or through intraoperatively digitized anatomy landmarks, a photorealistic rendering of the surgical action has been identified to greatly improve usability of these navigation systems. However, this may not hold true when the virtual representation of surgical instruments and implants is superimposed onto 2D projection images in a fluoroscopy-based navigation system due to the so-called image occlusion problem. Image occlusion occurs when the field of view of the fluoroscopic image is occupied by the virtual representation of surgical implants or instruments. In these situations, the surgeon may miss part of the image details, even if transparency and/or wire-frame rendering is used. In this paper, we propose to use non-photorealistic rendering to overcome this difficulty. Laboratory testing results on foamed plastic bones during various computer-assisted fluoroscopybased surgical procedures including total hip arthroplasty and long bone fracture reduction and osteosynthesis are shown.

Radiation exposure and safety practices during pediatric central line placement

PubMed Central

Saeman, Melody R.; Burkhalter, Lorrie S.; Blackburn, Timothy J.; Murphy, Joseph T.

2015-01-01

Purpose Pediatric surgeons routinely use fluoroscopy for central venous line (CVL) placement. We examined radiation safety practices and patient/surgeon exposure during fluoroscopic CVL. Methods Fluoroscopic CVL procedures performed by 11 pediatric surgeons in 2012 were reviewed. Fluoroscopic time (FT), patient exposure (mGy), and procedural data were collected. Anthropomorphic phantom simulations were used to calculate scatter and dose (mSv). Surgeons were surveyed regarding safety practices. Results 386 procedures were reviewed. Median FT was 12.8 seconds. Median patient estimated effective dose was 0.13 mSv. Median annual FT per surgeon was 15.4 minutes. Simulations showed no significant difference (p = 0.14) between reported exposures (median 3.5 mGy/min) and the modeled regression exposures from the C-arm default mode (median 3.4 mGy/min). Median calculated surgeon exposure was 1.5 mGy/year. Eight of 11 surgeons responded to the survey. Only three reported 100% lead protection and frequent dosimeter use. Conclusion We found non-standard radiation training, safety practices, and dose monitoring for the 11 surgeons. Based on simulations, the C-arm default setting was typically used instead of low dose. While most CVL procedures have low patient/surgeon doses, every effort should be used to minimize patient and occupational exposure, suggesting the need for formal hands-on training for non-radiologist providers using fluoroscopy. PMID:25837269

Study of scattered radiation during fluoroscopy in hip surgery*

PubMed Central

Lesyuk, Oksana; Sousa, Patrick Emmanuel; Rodrigues, Sónia Isabel do Espirito Santo; Abrantes, António Fernando; de Almeida, Rui Pedro Pereira; Pinheiro, João Pedro; Azevedo, Kevin Barros; Ribeiro, Luís Pedro Vieira

2016-01-01

Objective To measure the scattered radiation dose at different positions simulating hip surgery. Materials and Methods We simulated fluoroscopy-assisted hip surgery in order to study the distribution of scattered radiation in the operating room. To simulate the patient, we used a anthropomorphic whole-body phantom, and we used an X-ray-specific detector to quantify the radiation. Radiographs were obtained with a mobile C-arm X-ray system in continuous scan mode, with the tube at 0º (configuration 1) or 90º (configuration 2). The operating parameters employed (voltage, current, and exposure time) were determined by a statistical analysis based on the observation of orthopedic surgical procedures involving the hip. Results For all measurements, higher exposures were observed in configuration 2. In the measurements obtained as a function of height, the maximum dose rates observed were 1.167 (± 0.023) µSv/s and 2.278 (± 0.023) µSv/s in configurations 1 and 2, respectively, corresponding to the chest level of health care professionals within the operating room. Proximal to the patient, the maximum values were recorded in the position occupied by the surgeon. Conclusion We can conclude that, in the scenario under study, health care professionals workers are exposed to low levels of radiation, and that those levels can be reduced through the use of personal protective equipment. PMID:27777477

Accuracy and calibration of integrated radiation output indicators in diagnostic radiology: A report of the AAPM Imaging Physics Committee Task Group 190

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, Pei-Jan P., E-mail: Pei-Jan.Lin@vcuhealth.org; Schueler, Beth A.; Balter, Stephen

2015-12-15

Due to the proliferation of disciplines employing fluoroscopy as their primary imaging tool and the prolonged extensive use of fluoroscopy in interventional and cardiovascular angiography procedures, “dose-area-product” (DAP) meters were installed to monitor and record the radiation dose delivered to patients. In some cases, the radiation dose or the output value is calculated, rather than measured, using the pertinent radiological parameters and geometrical information. The AAPM Task Group 190 (TG-190) was established to evaluate the accuracy of the DAP meter in 2008. Since then, the term “DAP-meter” has been revised to air kerma-area product (KAP) meter. The charge of TGmore » 190 (Accuracy and Calibration of Integrated Radiation Output Indicators in Diagnostic Radiology) has also been realigned to investigate the “Accuracy and Calibration of Integrated Radiation Output Indicators” which is reflected in the title of the task group, to include situations where the KAP may be acquired with or without the presence of a physical “meter.” To accomplish this goal, validation test protocols were developed to compare the displayed radiation output value to an external measurement. These test protocols were applied to a number of clinical systems to collect information on the accuracy of dose display values in the field.« less

Urethral Stenting for Obstructive Uropathy Utilizing Digital Radiography for Guidance: Feasibility and Clinical Outcome in 26 Dogs.

PubMed

Radhakrishnan, A

2017-03-01

Urethral stent placement is an interventional treatment option to alleviate urethral outflow obstruction. It has been described utilizing fluoroscopy, but fluoroscopy is not as readily available in private practice as digital radiography. To describe the use of digital radiography for urethral stent placement in dogs with obstructive uropathy. Twenty-six client-owned dogs presented for dysuria associated with benign and malignant causes of obstructive uropathy that underwent urethral stent placement. Retrospective study. Causes of obstructive uropathy included transitional cell carcinoma, prostatic carcinoma, hemangiosarcoma, obstructive proliferative urethritis, compressive vaginal leiomyosarcoma, and detrusor-sphincter dyssynergia. Survival time range was 1-48 months (median, 5 months). All dogs were discharged from the hospital with urine outflow restored. Intraprocedural complications included guide wire penetration of the urethral wall in 1 dog and improper stent placement in a second dog. Both complications were successfully managed at the time of the procedure with no follow-up problems noted in either patient. Urethral stent placement can be successfully performed utilizing digital radiography. The complications experienced can be avoided by more cautious progression with each step through the procedure and serial radiography. The application of digital radiography may allow treatment of urethral obstruction to become more readily available. Copyright © 2017 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

Fluoroscopic and radiographic evaluation of tracheal collapse in dogs: 62 cases (2001-2006).

PubMed

Macready, Dawn M; Johnson, Lynelle R; Pollard, Rachel E

2007-06-15

To compare the use of radiography and fluoroscopy for detection and grading of tracheal collapse in dogs. Retrospective case series. Animals-62 dogs with tracheal collapse. For each dog, tracheal collapse was confirmed fluoroscopically and lateral cervical and thoracic radiographic views were reviewed. A board-certified radiologist (who was unaware of the dogs' clinical history) evaluated the cervical, thoracic inlet, thoracic, carinal, and main stem bronchial regions in all fluoroscopic videos and radiographic images for evidence of collapse. Cervical, thoracic inlet, thoracic, and carinal regions in both radio-graphic and fluoroscopic studies were graded for collapse (0%, 25%, 50%, 75%, or 100% decrease in diameter). Lateral cervical and thoracic radiographic images were available for 54 dogs, and inspiratory and expiratory lateral cervical and thoracic radiographic images were available for 8 dogs. For detection of tracheal collapse, assessment of radiographic views was sensitive and had the best negative predictive value in the cervical and thoracic inlet regions. Assessment of radiographic views was most specific and had the best positive predictive value in the thoracic inlet, thoracic, carina, and main stem bronchial regions. Radiography underestimated the degree of collapse in all areas. Review of inspiratory and expiratory views improved the accuracy of radiography for tracheal collapse diagnosis only slightly. Compared with fluoroscopy, radiography underestimated the frequency and degree of tracheal collapse. However, radiography appears to be useful for screening dogs with potential tracheal collapse.

A novel electromagnetic navigation tool for acetabular surgery.

PubMed

Lehmann, Wolfgang; Rueger, Johannes M; Nuechtern, Jakob; Grossterlinden, Lars; Kammal, Michael; Hoffmann, Michael

2015-10-01

Acetabular fracture surgery is demanding and screw placement along narrow bony corridors remains challenging. It necessitates x-ray radiation for fluoroscopically assisted screw insertion. The purpose of this cadaver study was to evaluate the feasibility, accuracy and operation time of a novel electromagnetic navigation system for screw insertion along predefined acetabular corridors. A controlled laboratory study with a total of 24 electromagnetically navigated screw insertions was performed on 8 cadaveric acetabula. 3 peri-acetabular bony corridors (QSS, Quadrilateral Surface Screw; IAS, Infra-Acetabular Screw; PCS, Posterior Column Screw) were defined and screws were placed in a defined order without fluoroscopy. Operation time was documented. Postoperative CT scans were performed to analyse accuracy of screw placement. Mean cadaver age was 70.4 ± 11.7. Successful screw placement was accomplished in 22 out of 24 (91.7%) cases. The overall mean time for all 3 acetabular screws was 576.6 ± 75.9s. All 3 complications occurred during the placement of the IAS due to an impassable narrow bony corridor. QSS mean length was 50 ± 5mm, IAS mean length was 85 ± 10mm and PCS mean length was 120 ± 5mm. In this cadaver study the novel electromagnetic navigation system was feasible to allow accurate screw placement without fluoroscopy in defined narrow peri-acetabular bony corridors. Copyright © 2015 Elsevier Ltd. All rights reserved.

Accuracy evaluation of fluoroscopy-based 2D and 3D pose reconstruction with unicompartmental knee arthroplasty.

PubMed

Van Duren, B H; Pandit, H; Beard, D J; Murray, D W; Gill, H S

2009-04-01

The recent development in Oxford lateral unicompartmental knee arthroplasty (UKA) design requires a valid method of assessing its kinematics. In particular, the use of single plane fluoroscopy to reconstruct the 3D kinematics of the implanted knee. The method has been used previously to investigate the kinematics of UKA, but mostly it has been used in conjunction with total knee arthroplasty (TKA). However, no accuracy assessment of the method when used for UKA has previously been reported. In this study we performed computer simulation tests to investigate the effect of the different geometry of the unicompartmental implant has on the accuracy of the method in comparison to the total knee implants. A phantom was built to perform in vitro tests to determine the accuracy of the method for UKA. The computer simulations suggested that the use of the method for UKA would prove less accurate than for TKA's. The rotational degrees of freedom for the femur showed greatest disparity between the UKA and TKA. The phantom tests showed that the in-plane translations were accurate to <0.5mm RMS and the out-of-plane translations were less accurate with 4.1mm RMS. The rotational accuracies were between 0.6 degrees and 2.3 degrees which are less accurate than those reported in the literature for TKA, however, the method is sufficient for studying overall knee kinematics.

Selective management of embolized intracardiac missiles.

PubMed

Gandhi, S K; Marts, B C; Mistry, B M; Brown, J W; Durham, R M; Mazuski, J E

1996-07-01

Intracardiac projectiles are occasionally found in stable patients who have sustained penetrating trauma. These missiles may arise from embolization from a peripheral injury site. We describe 3 patients with embolized intracardiac projectiles. The diagnosis was suggested by the presence of a foreign body within the cardiac silhouette on chest roentgenograms and was confirmed using fluoroscopy, echocardiography, or computed tomography. The management of embolized intracardiac missiles should be individualized to each patient. All of our patients had fixed intracavitary right-sided missiles and were successfully managed expectantly.

[Dysphagia and swallowing rehabilitation].

PubMed

Shigematsu, Takashi; Fujishima, Ichiro

2015-02-01

Dysphagia is a life-threatening disorder caused by many medical conditions such as stroke, neurological disorders, tumors, etc. The symptoms of dysphagia are quite variable and diagnosed by observation or through screening involving instrumental swallowing examinations such as video-fluoroscopy and video-endoscopy, to determine functional severity and treatment-prognosis. Direct- and indirect-therapy is used with and without food, respectively. Swallowing rehabilitation is very effective, and could be used in conjunction with compensatory techniques. Here we present an overview of dysphagia and swallowing rehabilitation.

MO-G-18A-01: Radiation Dose Reducing Strategies in CT, Fluoroscopy and Radiography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mahesh, M; Gingold, E; Jones, A

2014-06-15

Advances in medical x-ray imaging have provided significant benefits to patient care. According to NCRP 160, there are more than 400 million x-ray procedures performed annually in the United States alone that contributes to nearly half of all the radiation exposure to the US population. Similar growth trends in medical x-ray imaging are observed worldwide. Apparent increase in number of medical x-ray imaging procedures, new protocols and the associated radiation dose and risk has drawn considerable attention. This has led to a number of technological innovations such as tube current modulation, iterative reconstruction algorithms, dose alerts, dose displays, flat panelmore » digital detectors, high efficient digital detectors, storage phosphor radiography, variable filters, etc. that are enabling users to acquire medical x-ray images at a much lower radiation dose. Along with these, there are number of radiation dose optimization strategies that users can adapt to effectively lower radiation dose in medical x-ray procedures. The main objectives of this SAM course are to provide information and how to implement the various radiation dose optimization strategies in CT, Fluoroscopy and Radiography. Learning Objectives: To update impact of technological advances on dose optimization in medical imaging. To identify radiation optimization strategies in computed tomography. To describe strategies for configuring fluoroscopic equipment that yields optimal images at reasonable radiation dose. To assess ways to configure digital radiography systems and recommend ways to improve image quality at optimal dose.« less

Respiratory motion compensated overlay of surface models from cardiac MR on interventional x-ray fluoroscopy for guidance of cardiac resynchronization therapy procedures

NASA Astrophysics Data System (ADS)

Manzke, R.; Bornstedt, A.; Lutz, A.; Schenderlein, M.; Hombach, V.; Binner, L.; Rasche, V.

2010-02-01

Various multi-center trials have shown that cardiac resynchronization therapy (CRT) is an effective procedure for patients with end-stage drug invariable heart failure (HF). Despite the encouraging results of CRT, at least 30% of patients do not respond to the treatment. Detailed knowledge of the cardiac anatomy (coronary venous tree, left ventricle), functional parameters (i.e. ventricular synchronicity) is supposed to improve CRT patient selection and interventional lead placement for reduction of the number of non-responders. As a pre-interventional imaging modality, cardiac magnetic resonance (CMR) imaging has the potential to provide all relevant information. With functional information from CMR optimal implantation target sites may be better identified. Pre-operative CMR could also help to determine whether useful vein target segments are available for lead placement. Fused with X-ray, the mainstay interventional modality, improved interventional guidance for lead-placement could further help to increase procedure outcome. In this contribution, we present novel and practicable methods for a) pre-operative functional and anatomical imaging of relevant cardiac structures to CRT using CMR, b) 2D-3D registration of CMR anatomy and functional meshes with X-ray vein angiograms and c) real-time capable breathing motion compensation for improved fluoroscopy mesh overlay during the intervention based on right ventricular pacer lead tracking. With these methods, enhanced interventional guidance for left ventricular lead placement is provided.

Mobile augmented reality for computer-assisted percutaneous nephrolithotomy.

PubMed

Müller, Michael; Rassweiler, Marie-Claire; Klein, Jan; Seitel, Alexander; Gondan, Matthias; Baumhauer, Matthias; Teber, Dogu; Rassweiler, Jens J; Meinzer, Hans-Peter; Maier-Hein, Lena

2013-07-01

Percutaneous nephrolithotomy (PCNL) plays an integral role in treatment of renal stones. Creating percutaneous renal access is the most important and challenging step in the procedure. To facilitate this step, we evaluated our novel mobile augmented reality (AR) system for its feasibility of use for PCNL. A tablet computer, such as an iPad[Formula: see text], is positioned above the patient with its camera pointing toward the field of intervention. The images of the tablet camera are registered with the CT image by means of fiducial markers. Structures of interest can be superimposed semi-transparently on the video images. We present a systematic evaluation by means of a phantom study. An urological trainee and two experts conducted 53 punctures on kidney phantoms. The trainee performed best with the proposed AR system in terms of puncturing time (mean: 99 s), whereas the experts performed best with fluoroscopy (mean: 59 s). iPad assistance lowered radiation exposure by a factor of 3 for the inexperienced physician and by a factor of 1.8 for the experts in comparison with fluoroscopy usage. We achieve a mean visualization accuracy of 2.5 mm. The proposed tablet computer-based AR system has proven helpful in assisting percutaneous interventions such as PCNL and shows benefits compared to other state-of-the-art assistance systems. A drawback of the system in its current state is the lack of depth information. Despite that, the simple integration into the clinical workflow highlights the potential impact of this approach to such interventions.

Face and construct validity of a computer-based virtual reality simulator for ERCP.

PubMed

Bittner, James G; Mellinger, John D; Imam, Toufic; Schade, Robert R; Macfadyen, Bruce V

2010-02-01

Currently, little evidence supports computer-based simulation for ERCP training. To determine face and construct validity of a computer-based simulator for ERCP and assess its perceived utility as a training tool. Novice and expert endoscopists completed 2 simulated ERCP cases by using the GI Mentor II. Virtual Education and Surgical Simulation Laboratory, Medical College of Georgia. Outcomes included times to complete the procedure, reach the papilla, and use fluoroscopy; attempts to cannulate the papilla, pancreatic duct, and common bile duct; and number of contrast injections and complications. Subjects assessed simulator graphics, procedural accuracy, difficulty, haptics, overall realism, and training potential. Only when performance data from cases A and B were combined did the GI Mentor II differentiate novices and experts based on times to complete the procedure, reach the papilla, and use fluoroscopy. Across skill levels, overall opinions were similar regarding graphics (moderately realistic), accuracy (similar to clinical ERCP), difficulty (similar to clinical ERCP), overall realism (moderately realistic), and haptics. Most participants (92%) claimed that the simulator has definite training potential or should be required for training. Small sample size, single institution. The GI Mentor II demonstrated construct validity for ERCP based on select metrics. Most subjects thought that the simulated graphics, procedural accuracy, and overall realism exhibit face validity. Subjects deemed it a useful training tool. Study repetition involving more participants and cases may help confirm results and establish the simulator's ability to differentiate skill levels based on ERCP-specific metrics.

The Feasibility of 3D Printing Technology on the Treatment of Pilon Fracture and Its Effect on Doctor-Patient Communication.

PubMed

Zheng, Wenhao; Chen, Chunhui; Zhang, Chuanxu; Tao, Zhenyu; Cai, Leyi

2018-01-01

The aim of this study was to assess the feasibility and effectiveness of the three-dimensional (3D) printing technology in the treatment of Pilon fractures. 100 patients with Pilon fractures from March 2013 to December 2016 were enrolled in our study. They were divided randomly into 3D printing group ( n = 50) and conventional group ( n = 50). The 3D models were used to simulate the surgery and carry out the surgery according to plan in 3D printing group. Operation time, blood loss, fluoroscopy times, fracture union time, and fracture reduction as well as functional outcomes including VAS and AOFAS score and complications were recorded. To examine the feasibility of this approach, we invited surgeons and patients to complete questionnaires. 3D printing group showed significantly shorter operation time, less blood loss volume and fluoroscopy times, higher rate of anatomic reduction and rate of excellent and good outcome than conventional group ( P < 0.001, P < 0.001, P < 0.001, P = 0.040, and P = 0.029, resp.). However, no significant difference was observed in complications between the two groups ( P = 0.510). Furthermore, the questionnaire suggested that both surgeons and patients got high scores of overall satisfaction with the use of 3D printing models. Our study indicated that the use of 3D printing technology to treat Pilon fractures in clinical practice is feasible.

Medial Longitudinal Arch Angle Presents Significant Differences Between Foot Types: A Biplane Fluoroscopy Study.

PubMed

Balsdon, Megan E R; Bushey, Kristen M; Dombroski, Colin E; LeBel, Marie-Eve; Jenkyn, Thomas R

2016-10-01

The structure of the medial longitudinal arch (MLA) affects the foot's overall function and its ability to dissipate plantar pressure forces. Previous research on the MLA includes measuring the calcaneal-first metatarsal angle using a static sagittal plane radiograph, a dynamic height-to-length ratio using marker clusters with a multisegment foot model, and a contained angle using single point markers with a multisegment foot model. The objective of this study was to use biplane fluoroscopy to measure a contained MLA angle between foot types: pes planus (low arch), pes cavus (high arch), and normal arch. Fifteen participants completed the study, five from each foot type. Markerless fluoroscopic radiostereometric analysis (fRSA) was used with a three-dimensional model of the foot bones and manually matching those bones to a pair of two-dimensional radiographic images during midstance of gait. Statistically significant differences were found between barefoot arch angles of the normal and pes cavus foot types (p = 0.036), as well as between the pes cavus and pes planus foot types (p = 0.004). Dynamic walking also resulted in a statistically significant finding compared to the static standing trials (p = 0.014). These results support the classification of individuals following a physical assessment by a foot specialist for those with pes cavus and planus foot types. The differences between static and dynamic kinematic measurements were also supported using this novel method.

Urological diagnosis using clinical PACS

NASA Astrophysics Data System (ADS)

Mills, Stephen F.; Spetz, Kevin S.; Dwyer, Samuel J., III

1995-05-01

Urological diagnosis using fluoroscopy images has traditionally been performed using radiographic films. Images are generally acquired in conjunction with the application of a contrast agent, processed to create analog films, and inspected to ensure satisfactory image quality prior to being provided to a radiologist for reading. In the case of errors the entire process must be repeated. In addition, the radiologist must then often go to a particular reading room, possibly in a remote part of the healthcare facility, to read the images. The integration of digital fluoroscopy modalities with clinical PACS has the potential to significantly improve the urological diagnosis process by providing high-speed access to images at a variety of locations within a healthcare facility without costly film processing. The PACS additionally provides a cost-effective and reliable means of long-term storage and allows several medical users to simultaneously view the same images at different locations. The installation of a digital data interface between the existing clinically operational PACS at the University of Virginia Health Sciences Center and a digital urology fluoroscope is described. Preliminary user interviews that have been conducted to determine the clinical effectiveness of PACS workstations for urological diagnosis are discussed. The specific suitability of the workstation medium is discussed, as are overall advantages and disadvantages of the hardcopy and softcopy media in terms of efficiency, timeliness and cost. Throughput metrics and some specific parameters of gray-scale viewing stations and the expected system impacts resulting from the integration of a urology fluoroscope with PACS are also discussed.

Marker detection evaluation by phantom and cadaver experiments for C-arm pose estimation pattern

NASA Astrophysics Data System (ADS)

Steger, Teena; Hoßbach, Martin; Wesarg, Stefan

2013-03-01

C-arm fluoroscopy is used for guidance during several clinical exams, e.g. in bronchoscopy to locate the bronchoscope inside the airways. Unfortunately, these images provide only 2D information. However, if the C-arm pose is known, it can be used to overlay the intrainterventional fluoroscopy images with 3D visualizations of airways, acquired from preinterventional CT images. Thus, the physician's view is enhanced and localization of the instrument at the correct position inside the bronchial tree is facilitated. We present a novel method for C-arm pose estimation introducing a marker-based pattern, which is placed on the patient table. The steel markers form a pattern, allowing to deduce the C-arm pose by use of the projective invariant cross-ratio. Simulations show that the C-arm pose estimation is reliable and accurate for translations inside an imaging area of 30 cm x 50 cm and rotations up to 30°. Mean error values are 0.33 mm in 3D space and 0.48 px in the 2D imaging plane. First tests on C-arm images resulted in similarly compelling accuracy values and high reliability in an imaging area of 30 cm x 42.5 cm. Even in the presence of interfering structures, tested both with anatomy phantoms and a turkey cadaver, high success rates over 90% and fully satisfying execution times below 4 sec for 1024 px × 1024 px images could be achieved.

Transcardiac endograft delivery for endovascular treatment of the ascending aorta: a feasibility study in pigs.

PubMed

Wipper, Sabine; Lohrenz, Christina; Ahlbrecht, Oliver; Carpenter, Sebastian W; Tsilimparis, Nikolaos; Kersten, Jan Felix; Detter, Christian; Debus, Eike S; Kölbel, Tilo

2015-06-01

To compare the technical feasibility and hemodynamic alterations during antegrade transcardiac access routes vs conventional transfemoral access (TFA) for endovascular treatment of the ascending aorta in a porcine model. Antegrade transseptal access (TSA), transapical access (TAA), and TFA were used for implantation of custom-made endografts into the ascending aorta under fluoroscopy (6 pigs each). Hemodynamic parameters, myocardial and cerebral blood flow, and carotid artery blood flow were evaluated during baseline (T1), sheath advancement (T2), after sheath retraction (T3), and after endograft deployment (T4). Endograft deployment was feasible in all animals; all coronary arteries remained patent. Hemodynamic parameters were comparable in all 3 study groups during all measurements. During T2, transient hemodynamic alteration occurred in all groups, with transient severe valve insufficiency in TSA and TAA reflected by the higher pulmonary to mean arterial pressure ratio (p<0.05) as compared with TFA. Values stabilized again at T3 and remained stable until T4. The innominate artery was partially occluded in 4 (TSA), 3 (TAA), and 5 (TFA) animals. There was no deterioration of myocardial or cerebral perfusion during the procedures. Endograft deployment and fluoroscopy times during TAA were shorter than in TSA and TFA. TSA, TFA, and TAA to the ascending aorta are feasible for endograft delivery to the ascending aorta in a porcine model. Transient hemodynamic instability in TSA and TAA recovered to near preoperative values. TAA appeared technically easier. © The Author(s) 2015.

Imaging Techniques in Percutaneous Cardiac Structural Interventions: Atrial Septal Defect Closure and Left Atrial Appendage Occlusion.

PubMed

Rodríguez Fernández, Antonio; Bethencourt González, Armando

2016-08-01

Because of advances in cardiac structural interventional procedures, imaging techniques are playing an increasingly important role. Imaging studies show sufficient anatomic detail of the heart structure to achieve an excellent outcome in interventional procedures. Up to 98% of atrial septal defects at the ostium secundum can be closed successfully with a percutaneous procedure. Candidates for this type of procedure can be identified through a systematic assessment of atrial septum anatomy, locating and measuring the size and shape of all defects, their rims, and the degree and direction of shunting. Three dimensional echocardiography has significantly improved anatomic assessments and the end result itself. In the future, when combined with other imaging techniques such as cardiac computed tomography and fluoroscopy, 3-dimensional echocardiography will be particularly useful for procedure guidance. Percutaneous closure of the left atrial appendage offers an alternative for treating patients with atrial fibrillation and contraindication for oral anticoagulants. In the future, the clinical focus may well turn to stroke prevention in selected patients. Percutaneous closure is effective and safe; device implantation is successful in 94% to 99% of procedures. However, the procedure requires an experienced cardiac structural interventional team. At present, 3-dimensional echocardiography is the most appropriate imaging technique to assess anatomy suitability, select device type and size, guide the procedure alongside fluoroscopy, and to follow-up the patient afterwards. Copyright © 2016 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

Radiation- and reference base-free navigation procedure for placement of instruments and implants: application to retrograde drilling of osteochondral lesions of the knee joint.

PubMed

Müller, Matthias; Gras, Florian; Marintschev, Ivan; Mückley, Thomas; Hofmann, Gunter O

2009-01-01

A novel, radiation- and reference base-free procedure for placement of navigated instruments and implants was developed and its practicability and precision in retrograde drillings evaluated in an experimental setting. Two different guidance techniques were used: One experimental group was operated on using the radiation- and reference base-free navigation technique (Fluoro Free), and the control group was operated on using standard fluoroscopy for guidance. For each group, 12 core decompressions were simulated by retrograde drillings in different artificial femurs following arthroscopic determination of the osteochondral lesions. The final guide-wire position was evaluated by postoperative CT analysis using vector calculation. High precision was achieved in both groups, but operating time was significantly reduced in the navigated group as compared to the control group. This was due to a 100% first-pass accuracy of drilling in the navigated group; in the control group a mean of 2.5 correction maneuvers per drilling were necessary. Additionally, the procedure was free of radiation in the navigated group, whereas 17.2 seconds of radiation exposure time were measured in the fluoroscopy-guided group. The developed Fluoro Free procedure is a promising and simplified approach to navigating different instruments as well as implants in relation to visually or tactilely placed pointers or objects without the need for radiation exposure or invasive fixation of a dynamic reference base in the bone.

The Feasibility of 3D Printing Technology on the Treatment of Pilon Fracture and Its Effect on Doctor-Patient Communication

PubMed Central

Zheng, Wenhao; Chen, Chunhui; Zhang, Chuanxu; Tao, Zhenyu

2018-01-01

Purpose The aim of this study was to assess the feasibility and effectiveness of the three-dimensional (3D) printing technology in the treatment of Pilon fractures. Methods 100 patients with Pilon fractures from March 2013 to December 2016 were enrolled in our study. They were divided randomly into 3D printing group (n = 50) and conventional group (n = 50). The 3D models were used to simulate the surgery and carry out the surgery according to plan in 3D printing group. Operation time, blood loss, fluoroscopy times, fracture union time, and fracture reduction as well as functional outcomes including VAS and AOFAS score and complications were recorded. To examine the feasibility of this approach, we invited surgeons and patients to complete questionnaires. Results 3D printing group showed significantly shorter operation time, less blood loss volume and fluoroscopy times, higher rate of anatomic reduction and rate of excellent and good outcome than conventional group (P < 0.001, P < 0.001, P < 0.001, P = 0.040, and P = 0.029, resp.). However, no significant difference was observed in complications between the two groups (P = 0.510). Furthermore, the questionnaire suggested that both surgeons and patients got high scores of overall satisfaction with the use of 3D printing models. Conclusion Our study indicated that the use of 3D printing technology to treat Pilon fractures in clinical practice is feasible. PMID:29581985

Value of Duplex Ultrasound Assistance for Thromboaspiration and Dilation of Thrombosed Native Arterio-Venous Fistulae

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garcia-Medina, J., E-mail: josegmedina57@gmail.com

2013-12-15

Purpose: To evaluate the value of duplex ultrasound assistance during thromboaspiration of thrombosed arteriovenous fistulae for haemodialysis. Materials and Methods: We prospectively studied 54 thrombosed native fistulae (23 with total thrombosis and 31 with partial thrombosis), in which we performed manual thromboaspiration guided by ultrasonography associated with fluoroscopy. Results: The fistulae were located in the forearm (n = 39) or in the upper arm (n = 15) of 46 patients. Mean patient age was 65 years, and hypertension was the most common risk factor (74 %). Mean access age was 928 days (range 69-2,290), and most fistulae were on themore » left side (41 cases, 75.92 %). The success rate was 83 % in the total thrombosis group and 100 % in the partial thrombosis group. Including initial failures, the respective primary patency rates in the total thrombosis group and the partial thrombosis group were, respectively, 83 {+-} 8 % (n = 20) and 87 {+-} 6 % (n = 28) at 1 month, 39 {+-} 10 % (n = 10) and 61 {+-} 8 % (n = 20) at 6 months, and 17 {+-} 8 % (n = 5) and 26 {+-} 8 % (n = 9) at 1 year. The mean decrease of fluoroscopy time with ultrasound was 3 min (range 1-5). The mean decrease of radiation dose was 2.6 Gy cm Superscript-Two (range 0.9-4.3]. Conclusion: Ultrasound is a feasible and useful tool in the management of thrombosed native fistulae, thus decreasing radiation exposure, and has no detrimental effect on success rates.« less

Intravascular US-Guided Portal Vein Access: Improved Procedural Metrics during TIPS Creation.

PubMed

Gipson, Matthew G; Smith, Mitchell T; Durham, Janette D; Brown, Anthony; Johnson, Thor; Ray, Charles E; Gupta, Rajan K; Kondo, Kimi L; Rochon, Paul J; Ryu, Robert K

2016-08-01

To evaluate transjugular intrahepatic portosystemic shunt (TIPS) outcomes and procedure metrics with the use of three different image guidance techniques for portal vein (PV) access during TIPS creation. A retrospective review of consecutive patients who underwent TIPS procedures for a range of indications during a 28-month study period identified a population of 68 patients. This was stratified by PV access techniques: fluoroscopic guidance with or without portography (n = 26), PV marker wire guidance (n = 18), or intravascular ultrasound (US) guidance (n = 24). Procedural outcomes and procedural metrics, including radiation exposure, contrast agent volume used, procedure duration, and PV access time, were analyzed. No differences in demographic or procedural characteristics were found among the three groups. Technical success, technical success of the primary planned approach, hemodynamic success, portosystemic gradient, and procedure-related complications were not significantly different among groups. Fluoroscopy time (P = .003), air kerma (P = .01), contrast agent volume (P = .003), and total procedural time (P = .02) were reduced with intravascular US guidance compared with fluoroscopic guidance. Fluoroscopy time (P = .01) and contrast agent volume (P = .02) were reduced with intravascular US guidance compared with marker wire guidance. Intravascular US guidance of PV access during TIPS creation not only facilitates successful TIPS creation in patients with challenging anatomy, as suggested by previous investigations, but also reduces important procedure metrics including radiation exposure, contrast agent volume, and overall procedure duration compared with fluoroscopically guided TIPS creation. Copyright © 2016 SIR. Published by Elsevier Inc. All rights reserved.

Preliminary Experience with use of Qureshi-5 Catheters for Diagnostic Cerebral Angiography.

PubMed

Qureshi, Adnan I; Yan, Xiao; Liu, HongLiang

2015-05-01

A catheter technique was developed to overcome current challenges in the stabilization and manipulation of catheter in tortuous arteries such as right subclavian artery and left common carotid artery. The new catheter has the following two lumens: first lumen can accommodate a 0.035-inch guide wire (lumen A) and a curved shape at the distal end; the second lumen can accommodate a 0.018-inch guide wire and terminates at the beginning of the distal curve of the first lumen (lumen B). The catheter is withdrawn or advanced over the 0.018-inch guide wire and the curved free end of catheter manipulated until the end engages the origin of the target artery. Subsequently, either contrast can be injected or a 0.035-inch guide wire advanced into the target artery. The catheters were used in two patients to perform diagnostic cerebral angiography through a 6F introducer sheath placed in the right common femoral artery. The left and right common carotid arteries and left and right vertebral arteries were catheterized in first patient (contrast used 50 ml; fluoroscopy time 20:09 min). The left and right internal carotid arteries, left and right subclavian arteries, and left external carotid artery were catheterized in second patient (contrast used 40 ml; fluoroscopy time 13:56 min). No complications were observed in either of the two patients. The performance of the new catheter for catheterization of multiple arteries in two patients was considered adequate with high-quality angiographic image acquisitions.

Radiofrequency Ablation versus Cryoablation in the Treatment of Paroxysmal Atrial Fibrillation: A Meta-Analysis

PubMed Central

Hachem, Ali H.; Marine, Joseph E.; Tahboub, Housam A.; Kamdar, Sana; Kanjwal, Shaffi; Soni, Ronak

2018-01-01

Background Pulmonary vein isolation is commonly performed using radiofrequency energy with cryoablation gaining acceptance. We performed a meta-analysis of randomized controlled trials which compared radiofrequency versus cryoablation for patients with atrial fibrillation. Methods A systematic search strategy identified both published and unpublished articles from inception to November 10, 2016, in multiple databases. The primary outcomes for this meta-analysis were long-term freedom from atrial fibrillation at 12-month follow-up and overall postoperative complication rates. For all included studies, the methodological quality was assessed through the Cochrane Collaboration's tool for risk of bias. Results A total of 247 articles were identified with eight being included in this review as they satisfied the prespecified inclusion criteria. Overall, there was no significant difference in freedom from atrial fibrillation at ≥12-month follow-up between those receiving cryoballoon and radiofrequency ablation, respectively (OR = 0.98, CI = 0.67–1.43, I2 = 56%, p=0.90). Additionally, the secondary outcomes of duration of ablation, fluoroscopy time, and ablation time failed to reach significance. Cryoballoon ablation had significantly greater odds of postoperative phrenic nerve injury at 12-month follow-up. Conclusions Our meta-analysis suggests that cryoballoon ablation provides comparable benefits with regard to freedom from atrial fibrillation at medium-term follow-up, fluoroscopy time, ablation time, operative duration, and overall complication rate in comparison to radiofrequency ablation. PMID:29805800

An Assessment of Common Approaches to Estimating Peak Skin Dose Resulting From Fluoroscopically Guided Interventions

NASA Astrophysics Data System (ADS)

Smith, Caleb Martin

Fluoroscopy guided procedures are increasing in complexity, and with that, Peak Skin Doses (PSD) that produce cutaneous radiation injury are a growing concern. Direct measurement of PSD is possible, but the decision to do so must be made in advance. PSD estimates and correctly monitoring their possible deterministic skin injuries are important to patient care. Three methods of indirect PSD estimation are examined for nine cases at MedStar Georgetown University Hospital. The aim of the study is to determine the magnitude of variation between these three methods for estimating the PSD. Method 1 (Fluoroscopy Time and Maximum Entrance Skin Exposure) was used at MedStar Georgetown University Hospital up until 2016. Methods 2 and 3 incorporate procedure information (Reference Point Air Kerma, Source-to-Patent distance, and Backscatter Factor) from DICOM (Digital Imaging and Communications in Medicine) tags into PSD estimates. Method 1 PSD estimates are vastly different, by as much as 136%, than those from Methods 2 and 3. Method 2 and 3 PSD estimates differ very little, 7.3% or less. Governing bodies have discounted Method 1 as a reliable dose metric because of its poor correlation with PSD. The accuracy of Method 2 is suitable to determine PSD and which dose band a patient fits so their injuries can be accurately monitored. Method 3, the most time intensive approach, should only be used in the case of a sentinel event where a full investigation is warranted.

Interatrial septum pacing guided by three-dimensional intracardiac echocardiography.

PubMed

Szili-Torok, Tamas; Kimman, Geert Jan P; Scholten, Marcoen F; Ligthart, Jurgen; Bruining, Nico; Theuns, Dominic A M J; Klootwijk, Peter J; Roelandt, Jos R T C; Jordaens, Luc J

2002-12-18

Currently, the interatrial septum (IAS) pacing site is indirectly selected by fluoroscopy and P-wave analysis. The aim of the present study was to develop a novel approach for IAS pacing using intracardiac echocardiography (ICE). Interatrial septum pacing may be beneficial for the prevention of paroxysmal atrial fibrillation. Cross-sectional images are acquired during a pull-back of the ICE transducer from the superior vena cava into the inferior vena cava by an electrocardiogram- and respiration-gated technique. Both atria are then reconstructed using three-dimensional (3D) imaging. Using an "en face" view of the IAS, the desired pacing site is selected. Following lead placement and electrical testing, another 3D reconstruction is performed to verify the final lead position. Twelve patients were included in this study. The IAS pacing was achieved in all patients including six suprafossal (SF) and six infrafossal (IF) lead locations all confirmed by 3D imaging. The mean duration times of atrial lead implantation and fluoroscopy were 70 +/- 48.9 min and 23.7 +/- 20.6 min, respectively. The IAS pacing resulted in a significant reduction of the P-wave duration as compared to sinus rhythm (98.9 +/- 19.3 ms vs. 141.3 +/- 8.6 ms; p < 0.002). The SF pacing showed a greater reduction of the P-wave duration than IF pacing (59.4 +/- 6.6 ms vs. 30.2 +/- 13.6 ms; p < 0.004). Three-dimensional ICE is a feasible tool for guiding IAS pacing.

Retrospective Analysis of the Accuracy of Ultrasound-Guided Magnetic Resonance Arthrogram Injections of the Hip in the Office Setting.

PubMed

Jernick, Michael; Walker Gallego, Edward; Nuzzo, Michael

2017-12-01

Ultrasound (US)-guided intra-articular hip injections have been proposed in the literature to be accurate, reliable, and safe alternatives to fluoroscopy-guided injections. To evaluate the accuracy of US-guided magnetic resonance (MR) arthrogram injections of the hip performed in the office setting by a single orthopaedic surgeon and elucidate the potential effects that patient age, sex, and body mass index (BMI) have on contrast placement. Case series; Level of evidence, 4. From a review of the senior author's office database, 89 patients (101 hips) who had US-guided MR arthrogram injections performed between December 2014 and June 2016 were identified. Official radiology reports were evaluated to determine whether extra-articular contrast was noted. Patient variables, including BMI, age, and sex, were evaluated between patients who had inappropriately placed contrast and those who did not. Of the 101 hip injections, there were 6 cases that demonstrated inadequate contrast placement within the joint, likely secondary to extravasation or incorrect placement; however, an MR arthrogram was adequately interpreted in all cases. There were no significant differences noted between those with appropriate versus inappropriate contrast placement when evaluating BMI ( P = .57), age ( P = .33), or sex ( P = .67), and neither group had an adverse event. US-guided injections are safe and accurate alternatives to fluoroscopy-guided injections in the office setting, with 94% accuracy. Furthermore, BMI, age, and sex did not play a statistically significant role among patients with inappropriately placed contrast.

Percutaneous CT and Fluoroscopy-Guided Screw Fixation of Pathological Fractures in the Shoulder Girdle: Technical Report of 3 Cases

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garnon, Julien, E-mail: juliengarnon@gmail.com; Koch, Guillaume, E-mail: Guillaume.koch@gmail.com; Ramamurthy, Nitin, E-mail: Nitin-ramamurthy@hotmail.com

ObjectiveTo review our initial experience with percutaneous CT and fluoroscopy-guided screw fixation of pathological shoulder-girdle fractures.Materials and MethodsBetween May 2014 and June 2015, three consecutive oncologic patients (mean age 65 years; range 57–75 years) with symptomatic pathological shoulder-girdle fractures unsuitable for surgery and radiotherapy underwent percutaneous image-guided screw fixation. Fractures occurred through metastases (n = 2) or a post-ablation cavity (n = 1). Mechanical properties of osteosynthesis were adjudged superior to stand-alone cementoplasty in each case. Cannulated screws were placed under combined CT and fluoroscopic guidance with complementary radiofrequency ablation or cementoplasty to optimise local palliation and secure screw fixation, respectively, in two cases. Follow-up wasmore » undertaken every few weeks until mortality or most recent appointment.ResultsFour pathological fractures were treated in three patients (2 acromion, 1 clavicular, 1 coracoid). Mean size of associated lesion was 2.6 cm (range 1–4.5 cm). Technical success was achieved in all cases (100 %), without complications. Good palliation and restoration of mobility were observed in two cases at 2–3 months; one case could not be followed due to early post-procedural oncologic mortality.ConclusionPercutaneous image-guided shoulder-girdle osteosynthesis appears technically feasible with good short-term efficacy in this complex patient subset. Further studies are warranted to confirm these promising initial results.« less

Bundle Adjustment-Based Stability Analysis Method with a Case Study of a Dual Fluoroscopy Imaging System

NASA Astrophysics Data System (ADS)

Al-Durgham, K.; Lichti, D. D.; Detchev, I.; Kuntze, G.; Ronsky, J. L.

2018-05-01

A fundamental task in photogrammetry is the temporal stability analysis of a camera/imaging-system's calibration parameters. This is essential to validate the repeatability of the parameters' estimation, to detect any behavioural changes in the camera/imaging system and to ensure precise photogrammetric products. Many stability analysis methods exist in the photogrammetric literature; each one has different methodological bases, and advantages and disadvantages. This paper presents a simple and rigorous stability analysis method that can be straightforwardly implemented for a single camera or an imaging system with multiple cameras. The basic collinearity model is used to capture differences between two calibration datasets, and to establish the stability analysis methodology. Geometric simulation is used as a tool to derive image and object space scenarios. Experiments were performed on real calibration datasets from a dual fluoroscopy (DF; X-ray-based) imaging system. The calibration data consisted of hundreds of images and thousands of image observations from six temporal points over a two-day period for a precise evaluation of the DF system stability. The stability of the DF system - for a single camera analysis - was found to be within a range of 0.01 to 0.66 mm in terms of 3D coordinates root-mean-square-error (RMSE), and 0.07 to 0.19 mm for dual cameras analysis. It is to the authors' best knowledge that this work is the first to address the topic of DF stability analysis.

Subarachnoid and basal cistern navigation through the sacral hiatus with guide wire assistance.

PubMed

Layer, Lauren; Riascos, Roy; Firouzbakht, Farhood; Amole, Adewumi; Von Ritschl, Rudiger; Dipatre, Pier; Cuellar, Hugo

2011-07-01

Intraspinal navigation with catheters and fiberscopes has shown feasible results for diagnosis and treatment of intraspinal and intracranial lesions. The most common approach, lumbar puncture, has allowed access to the spinal cord, however, coming with the difficulties of fiberscope damage and decreased torque for guidance. Our objective in this study is to allow an alternate access, the sacral hiatus, with guide wire assistance into the subarachnoid and intracranial structures, while easing the angle of entry and increasing torque. We advanced catheters with guide wire and fluoroscopy assistance into the sacral hiatus of three cadavers. After entry, the thecal sac was punctured and the catheter with guide wire was advanced rostrally until positioned in the basal cisterns of the brain. We confirmed catheter placement with contrast injection, autopsy, and dissection. In our study, the sacral hiatus was easily accessed, but resistance was found when attempting to puncture the thecal sac. The advancement of the catheter with guide wire assistance glided easily rostrally until some mild resistance was discovered at entry into the foramen magnum. With redirection, all catheters passed with ease into the basal cisterns. Positioning was confirmed with contrast injection with fluoroscopy evidence, autopsy, and dissection. There was no macroscopic or microscopic evidence of damage to the spinal roots, spinal cord, or cranial nerves. The sacral hiatus with guide wire assistance is an accessible conduit for uncomplicated entry into the subarachnoid and basal cistern space without damaging surrounding structures.

Efficacy of the Greater Occipital Nerve Block for Cervicogenic Headache: Comparing Classical and Subcompartmental Techniques.

PubMed

Lauretti, Gabriela R; Corrêa, Selma W R O; Mattos, Anita L

2015-09-01

The aim of the study was to compare the efficacy of the greater occipital nerve (GON) block using the classical technique and different volumes of injectate with the subcompartmental technique for the treatment of cervicogenic headache (CH). Thirty patients acted as his/her own control. All patients were submitted to the GON block by the classical technique with 10 mg dexamethasone, plus 40 mg lidocaine (5 mL volume). Patients were randomly allocated into 1 of 3 groups (n = 10) when pain VAS was > 3 cm. Each group was submitted to a GON subcompartmental technique (10 mg dexamethasone + 40 mg lidocaine + nonionic iodine contrast + saline) under fluoroscopy using either 5, 10, or 15 mL final volume. Analgesia and quality of life were evaluated. The classical GON technique resulted in 2 weeks of analgesia and less rescue analgesic consumption, compared to 24 weeks after the subcompartmental technique (P < 0.01). Quality of life improved at 2 and 24 weeks after the classical and the suboccipital techniques, respectively (P < 0.05). The data revealed that groups were similar regarding analgesia when compared to volume of injection (P > 0.05). While the classical technique for GON block resulted in only 2 weeks of analgesia, the subcompartmental technique resulted in at least 24 weeks of analgesia, being 5 mL volume sufficient for the performance of the block under fluoroscopy. © 2014 World Institute of Pain.

A new method to precisely control the depth of percutaneous screws into the pedicle by counting the rotation number of the screw with low radiation exposure: technical note.

PubMed

Li, Xu; Zhang, Feng; Zhang, Wenzhi; Shang, Xifu; Han, Jintao; Liu, Pengfei

2017-03-01

Technique note. To report a new method for precisely controlling the depth of percutaneous pedicle screws (PPS)-without radiation exposure to surgeons and less fluoroscopy exposure to patients than with conventional methods. PPS is widely used in minimal invasive spine surgery; the advantages include reduced muscle damage, pain, and hospital stays. However, placement of PPS demands repeated checking with fluoroscopy. Thus, radiation exposure is considerable for both surgeons and patients. The PPS depth was determined by counting rotations of the screws. The distance between screw threads can be measured for particular screws; thus, full rotations of the PPS results in the screw advancing in the pedicle the distance between screw threads. To fully insert screws into the pedicle, the number of full rotations is equal to the number of threads in the PPS. We applied this technique in 58 patients with thoracolumbar fracture. The position and depth of the screws was checked during the operation with the C-arm and after operation by anteroposterior X-ray film or computed tomography. No additional procedures were required to correct the screws; we observed no neurological deficits or malpositioning of the screws. In the screw placement procedure, the radiation exposure for surgeons is zero, and the patient is well protected from extensive radiation exposure. This method of counting rotation of screws is a safe way to precisely determine the depth of PPS in the placement procedure. IV.

Factors affecting results of fluoroscopy-guided facet joint injection: Probable differences in the outcome of treatment between pure facet joint hypertrophy and concomitant diseases.

PubMed

Albayrak, Akif; Ozkul, Baris; Balioglu, Mehmet Bulent; Atici, Yunus; Gultekin, Muhammet Zeki; Albayrak, Merih Dilan

2016-01-01

Retrospective cohort study. Facet joints are considered a common source of chronic low-back pain. To determine whether pathogens related to the facet joint arthritis have any effect on treatment failure. Facet joint injection was applied to 94 patients treated at our hospital between 2011 and 2012 (mean age 59.5 years; 80 women and 14 men). For the purpose of analysis, the patients were divided into two groups. Patients who only had facet hypertrophy were placed in group A (47 patients, 41 women and 6 men, mean age 55.3 years) and patients who had any additional major pathology to facet hypertrophy were placed in group B (47 patients, 39 women and 8 men, mean age 58.9 years). Injections were applied around the facet joint under surgical conditions utilizing fluoroscopy device guidance. A mixture of methylprednisolone and lidocaine was used as the injection ingredient. In terms of Oswestry Disability Index (ODI) and visual analog scale (VAS) scores, no significant difference was found between preinjection and immediate postinjection values in both groups, and the scores of group A patients were significantly lower (P < 0.005) compared with that of group B patients at the end of the third, sixth, and twelfth month. For low-back pain caused by facet hypertrophy, steroid injection around the facet joint is an effective treatment, but if there is an existing major pathology, it is not as effective.

A national patient dose survey and setting of reference levels for interventional radiology in Bulgaria.

PubMed

Zotova, R; Vassileva, J; Hristova, J; Pirinen, M; Järvinen, H

2012-06-01

A national study on patient dose values in interventional radiology and cardiology was performed in order to assess current practice in Bulgaria, to estimate the typical patient doses and to propose reference levels for the most common procedures. Fifteen units and more than 1,000 cases were included. Average values of the measured parameters for three procedures-coronary angiography (CA), combined procedure (CA + PCI) and lower limb arteriography (LLA)--were compared with data published in the literature. Substantial variations were observed in equipment and procedure protocols used. This resulted in variations in patient dose: air-kerma area product ranges were 4-339, 6-1,003 and 0.2-288 Gy cm(2) for CA, CA + PCI and LLA respectively. Reference levels for air kerma-area product were proposed: 40 Gy cm(2) for CA, 140 Gy cm(2) for CA + PCI and 45 Gy cm(2) for LLA. Auxiliary reference intervals were proposed for other dose-related parameters: fluoroscopy time, number of images and entrance surface air kerma rate in fluoroscopy and cine mode. There is an apparent necessity for improvement in the classification of peripheral procedures and for standardisation of the protocols applied. It is important that patient doses are routinely recorded and compared with reference levels. • Patient doses in interventional radiology are high and vary greatly • Better standardisation of procedures and techniques is needed to improve practice • Dose reference levels for most common procedures are proposed.

Single Center Retrospective Analysis of Conventional and Radial TIG Catheters for Transradial Diagnostic Coronary Angiography.

PubMed

Vorpahl, Marc; Koehler, Till; Foerst, Jason; Panagiotopoulos, Spyridon; Schleiting, Heinrich; Koss, Klaus; Ziegler, Gunda; Brinkmann, Hilmar; Seyfarth, Melchior; Tiroch, Klaus

2015-01-01

Current guidelines favor the radial approach for coronary angiography. Therefore, specialty radial diagnostic catheters were designed to engage both coronary arteries with a single device. However, it is unclear if single catheters are superior to conventional catheters. A retrospective analysis was performed of consecutive right radial coronary angiographies to determine catheter use, fluoroscopy time, radiation dosage, and consumption of contrast. Procedures were performed with a single TIG catheter or conventional catheters (CONV). Procedures with coronary artery bypass grafts or ventricular angiographies were excluded. 273 transradial procedures were performed successfully. 95 procedures were performed with CONV and 178 procedures with a TIG. Crossover to additional catheters was higher in TIG (15.2%) compared to CONV (5.3%, p = 0.02). Fluoroscopy time was comparable between CONV and TIG, without crossover (2.2 ± 1.2 min versus 2.3 ± 1.2 min; n.s.), however, greater in the case of crossover for CONV (5.8 ± 0.7) and TIG (7.6 ± 3.0; p = 0.0001). Radiation dosage was similar in CONV and the TIG, without crossover (1419 ± 1075, cGy∗cm(2) versus 1690 ± 1138; n.s.), however, greater for CONV (2374 ± 620) and TIG (3733 ± 2281, p = 0.05) with crossover. Overall, the amount of contrast was greater in TIG (56 ± 13 mL) versus CONV (48 ± 3 mL; p = 0.0003). CONV femoral catheters may be the primary choice for radial approach.

iPod touch-assisted instrumentation of the spine: a technical report.

PubMed

Jost, Gregory F; Bisson, Erica F; Schmidt, Meic H

2013-12-01

Instrumentation of the spine depends on choosing the correct insertion angles to implant screws. Although modern image guidance facilitates precise instrumentation of the spine, the equipment is costly and availability is limited. Although most surgeons use lateral fluoroscopy to guide instrumentation in the sagittal plane, the lateromedial angulation is often chosen by estimation. To overcome the associated uncertainty, iPod touch-based applications for measuring angles can be used to assist with screw implantation. To evaluate the use of the iPod touch to adjust instruments to the optimal axial insertion angle for placement of pedicle screws in the lumbar spine. Twenty lumbar pedicle screws in 5 consecutive patients were implanted using the iPod touch. The lateromedial angulation was measured on preoperative images and reproduced in the operative field with the iPod touch. The instruments to implant the screws were aligned with the side of the iPod for screw insertion. Actual screw angles were remeasured on postoperative imaging. We collected demographic, clinical, and operative data for each patient. In 16 of 20 screws, the accuracy of implantation was within 3 degrees of the ideal trajectory. The 4 screws with an angle mismatch of 7 to 13 degrees were all implanted at the caudal end of the exposure, where maintaining the planned angulation was impeded by strong muscles pushing medially. iPod touch-assisted instrumentation of the spine is a very simple technique, which, in combination with a lateral fluoroscopy, may guide placement of pedicle screws in the lumbar spine.

Skin dose mapping for fluoroscopically guided interventions.

PubMed

Johnson, Perry B; Borrego, David; Balter, Stephen; Johnson, Kevin; Siragusa, Daniel; Bolch, Wesley E

2011-10-01

To introduce a new skin dose mapping software system for interventional fluoroscopy dose assessment and to analyze the benefits and limitations of patient-phantom matching. In this study, a new software system was developed for visualizing patient skin dose during interventional fluoroscopy procedures. The system works by translating the reference point air kerma to the location of the patient's skin, which is represented by a computational model. In order to orient the model with the x-ray source, geometric parameters found within the radiation dose structured report (RDSR) are used along with a limited number of in-clinic measurements. The output of the system is a visual indication of skin dose mapped onto an anthropomorphic model at a resolution of 5 mm. In order to determine if patient-dependent and patient-sculpted models increase accuracy, peak skin dose was calculated for each of 26 patient-specific models and compared with doses calculated using an elliptical stylized model, a reference hybrid model, a matched patient-dependent model and one patient-sculpted model. Results were analyzed in terms of a percent difference using the doses calculated using the patient-specific model as the true standard. Anthropometric matching, including the use of both patient-dependent and patient-sculpted phantoms, was shown most beneficial for left lateral and anterior-posterior projections. In these cases, the percent difference using a reference model was between 8 and 20%, using a patient-dependent model between 7 and 15%, and using a patient-sculpted model between 3 and 7%. Under the table tube configurations produced errors less than 5% in most situations due to the flattening affects of the table and pad, and the fact that table height is the main determination of source-to-skin distance for these configurations. In addition to these results, several skin dose maps were produced and a prototype display system was placed on the in-clinic monitor of an interventional fluoroscopy system. The skin dose mapping program developed in this work represents a new tool that, as the RDSR becomes available through automated export or real-time streaming, can provide the interventional physician information needed to modify behavior when clinically appropriate. The program is nonproprietary and transferable, and also functions independent to the software systems already installed on the control room workstation. The next step will be clinical implementation where the workflow will be optimized along with further analysis of real-time capabilities.

New image-processing and noise-reduction software reduces radiation dose during complex endovascular procedures.

PubMed

Kirkwood, Melissa L; Guild, Jeffrey B; Arbique, Gary M; Tsai, Shirling; Modrall, J Gregory; Anderson, Jon A; Rectenwald, John; Timaran, Carlos

2016-11-01

A new proprietary image-processing system known as AlluraClarity, developed by Philips Healthcare (Best, The Netherlands) for radiation-based interventional procedures, claims to lower radiation dose while preserving image quality using noise-reduction algorithms. This study determined whether the surgeon and patient radiation dose during complex endovascular procedures (CEPs) is decreased after the implementation of this new operating system. Radiation dose to operators, procedure type, reference air kerma, kerma area product, and patient body mass index were recorded during CEPs on two Philips Allura FD 20 fluoroscopy systems with and without Clarity. Operator dose during CEPs was measured using optically stimulable, luminescent nanoDot (Landauer Inc, Glenwood, Ill) detectors placed outside the lead apron at the left upper chest position. nanoDots were read using a microStar ii (Landauer Inc) medical dosimetry system. For the CEPs in the Clarity group, the radiation dose to surgeons was also measured by the DoseAware (Philips Healthcare) personal dosimetry system. Side-by-side measurements of DoseAware and nanoDots allowed for cross-calibration between systems. Operator effective dose was determined using a modified Niklason algorithm. To control for patient size and case complexity, the average fluoroscopy dose rate and the dose per radiographic frame were adjusted for body mass index differences and then compared between the groups with and without Clarity by procedure. Additional factors, for example, physician practice patterns, that may have affected operator dose were inferred by comparing the ratio of the operator dose to procedural kerma area product with and without Clarity. A one-sided Wilcoxon rank sum test was used to compare groups for radiation doses, reference air kermas, and operating practices for each procedure type. The analysis included 234 CEPs; 95 performed without Clarity and 139 with Clarity. Practice patterns of operators during procedures with and without Clarity were not significantly different. For all cases, procedure radiation dose to the patient and the primary and assistant operators were significantly decreased in the Clarity group by 60% compared with the non-Clarity group. By procedure type, fluorography dose rates decreased from 44% for fenestrated endovascular repair and up to 70% with lower extremity interventions. Fluoroscopy dose rates also significantly decreased, from about 37% to 47%, depending on procedure type. The AlluraClarity system reduces the patient and primary operator's radiation dose by more than half during CEPs. This feature appears to be an effective tool in lowering the radiation dose while maintaining image quality. Copyright © 2016 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

Fluoroscopy-Guided Endoscopic Removal of Foreign Bodies.

PubMed

Kim, Junhwan; Ahn, Ji Yong; So, Seol; Lee, Mingee; Oh, Kyunghwan; Jung, Hwoon-Yong

2017-03-01

In most cases of ingested foreign bodies, endoscopy is the first treatment of choice. Moreover, emergency endoscopic removal is required for sharp and pointed foreign bodies such as animal or fish bones, food boluses, and button batteries due to the increased risks of perforation, obstruction, and bleeding. Here, we presented two cases that needed emergency endoscopic removal of foreign bodies without sufficient fasting time. Foreign bodies could not be visualized by endoscopy due to food residue; therefore, fluoroscopic imaging was utilized for endoscopic removal of foreign bodies in both cases.

Dynamic Chest Image Analysis: Evaluation of Model-Based Pulmonary Perfusion Analysis With Pyramid Images

DTIC Science & Technology

2001-10-25

Image Analysis aims to develop model-based computer analysis and visualization methods for showing focal and general abnormalities of lung ventilation and perfusion based on a sequence of digital chest fluoroscopy frames collected with the Dynamic Pulmonary Imaging technique 18,5,17,6. We have proposed and evaluated a multiresolutional method with an explicit ventilation model based on pyramid images for ventilation analysis. We have further extended the method for ventilation analysis to pulmonary perfusion. This paper focuses on the clinical evaluation of our method for

Dysphagia caused by a lateral medullary infarction syndrome (Wallenberg's syndrome)

PubMed Central

El Mekkaoui, Amine; Irhoudane, Hanane; Ibrahimi, Adil; El Yousfi, Mounia

2012-01-01

A 68-year-old man was referred to our hospital for a dysphagia evolving for 10 days. Clinical examination had found neurological signs as contralateral Horner's syndrome, ipsilateral palatal paresis, gait ataxia and hoarseness. Video-fluoroscopy showed a lack of passage of contrast medium to the distal esophagus. Esogastroduodenoscopy was normal. The cranial MRI had shown an acute ischemic stroke in the left lateral medullar region and the diagnosis of Wallenberg syndrome (WS) was established. WS remains an unknown cause of dysphagia in the clinical practice of the gastroenterologist. PMID:23077713

A United States marine presenting with hemoptysis after push-ups.

PubMed

Thurber, John S; Unger, Jason A; DeVries, William C

2014-04-01

We present an unusual case of right lower lobe intralobar pulmonary sequestration in a previously healthy and physical active 27-year-old U.S. Marine, who presented with new onset hemoptysis after doing push-ups. Diagnosis was obtained by chest X-ray and contrast computed tomography scan. Preoperatively the patient underwent fluoroscopy-guided embolization of the aberrant systemic artery supplying the sequestration. The segmental resection of the sequestration was then successfully performed through a muscle-sparing thoracotomy. Reprint & Copyright © 2014 Association of Military Surgeons of the U.S.

Collaborative Management of Missile Injury to Right Ventricle and Subsequent Pulmonary Embolization.

PubMed

Sibona, Agustin; Smith, Jason C; Srikureja, Daniel P; Sharma, Rahul; Mascetti, Carin; Razzouk, Anees J; Rabkin, David G

2018-05-30

Pulmonary embolization of a missile is a rare phenomenon. Localization after embolization can be confounding and there is no consensus on management. We report a case of a gunshot wound to the chest with preoperative and initial intraoperative imaging localizing the bullet to the right ventricle but a negative intraoperative exploration of the right-sided cardiac chambers. Intraoperative fluoroscopy allowed for immediate localization of the bullet to the hilum of the left lung with subsequent endovascular retrieval. Copyright © 2018. Published by Elsevier Inc.

Interventional Cardiology: What's New?

PubMed

Scansen, Brian A

2017-09-01

Interventional cardiology in veterinary medicine continues to expand beyond the standard 3 procedures of patent ductus arteriosus occlusion, balloon pulmonary valvuloplasty, and transvenous pacing. Opportunities for fellowship training; advances in equipment, including high-resolution digital fluoroscopy, real-time 3-dimensional transesophageal echocardiography, fusion imaging, and rotational angiography; ultrasound-guided access and vascular closure devices; and refinement of techniques, including cutting and high-pressure ballooning, intracardiac and intravascular stent implantation, septal defect occlusion, transcatheter valve implantation, and hybrid approaches, are likely to transform the field over the next decade. Copyright © 2017 Elsevier Inc. All rights reserved.

Extracorporeal shockwave therapy in calcifying tendinitis of the shoulder.

PubMed

Farr, Sebastian; Sevelda, Florian; Mader, Patrick; Graf, Alexandra; Petje, Gert; Sabeti-Aschraf, Manuel

2011-12-01

Strategies for extracorporeal shockwave therapy in calcifying tendinitis of the rotator cuff vary concerning quantity of sessions and doses. The purpose of this prospective pilot study was to determine the difference between the outcome of a single high-dosage extracorporeal shockwave therapy and two sessions of low-dosage extracorporeal shockwave therapy. This study compared a single high-level middle-energetic extracorporeal shockwave therapy (0.3 mJ/mm(2)) with a low-level middle-energetic extracorporeal shockwave therapy applied twice in a weekly interval (0.2 mJ/mm(2)). Thirty patients that suffered from calcifying tendinitis for at least 6 months received navigated, fluoroscopy-guided extracorporeal shockwave therapy. The gain of Constant Murley Score, Visual Analogue Scale during state of rest and weight-bearing situations ("stress") and radiographic progress was documented 6 and 12 weeks after therapy. In both groups, a significant reduction in pain during stress and improvement of function was observed. In contrast, no significant reduction in pain during rest was observed. No significant difference between both groups concerning reduction in the calcific deposit after 6 weeks was detected. Group B showed minor advantages in radiographical improvement after 12 weeks. In 36% of the patients, the calcific deposit completely dissoluted after 12 weeks. This pilot study indicates that a single high-level extracorporeal shockwave therapy may be as effective as two applications of a lower-dosed extracorporeal shockwave therapy for calcifying tendinitis. An effective single-session strategy could reduce treatment time, material costs and healthcare expenses and ionizing radiation in case of fluoroscopy guidance.

Radiation Exposure of Abdominal Cone Beam Computed Tomography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sailer, Anna M., E-mail: anni.sailer@mumc.nl; Schurink, Geert Willem H., E-mail: gwh.schurink@mumc.nl; Wildberger, Joachim E., E-mail: j.wildberger@mumc.nl

2015-02-15

PurposeTo evaluate patients radiation exposure of abdominal C-arm cone beam computed tomography (CBCT).MethodsThis prospective study was approved by the institutional review board; written, informed consent was waived. Radiation exposure of abdominal CBCT was evaluated in 40 patients who underwent CBCT during endovascular interventions. Dose area product (DAP) of CBCT was documented and effective dose (ED) was estimated based on organ doses using dedicated Monte Carlo simulation software with consideration of X-ray field location and patients’ individual body weight and height. Weight-dependent ED per DAP conversion factors were calculated. CBCT radiation dose was compared to radiation dose of procedural fluoroscopy. CBCTmore » dose-related risk for cancer was assessed.ResultsMean ED of abdominal CBCT was 4.3 mSv (95 % confidence interval [CI] 3.9; 4.8 mSv, range 1.1–7.4 mSv). ED was significantly higher in the upper than in the lower abdomen (p = 0.003) and increased with patients’ weight (r = 0.55, slope = 0.045 mSv/kg, p < 0.001). Radiation exposure of CBCT corresponded to the radiation exposure of on average 7.2 fluoroscopy minutes (95 % CI 5.5; 8.8 min) in the same region of interest. Lifetime risk of exposure related cancer death was 0.033 % or less depending on age and weight.ConclusionsMean ED of abdominal CBCT was 4.3 mSv depending on X-ray field location and body weight.« less

Volar plating for distal radius fractures--do not trust the image intensifier when judging distal subchondral screw length.

PubMed

Park, Derek H; Goldie, Boyd S

2012-09-01

The use of the volar plate to treat distal radius fractures is increasing but despite the theoretical advantages of a volar approach there have been reports of extensor tendon ruptures due to prominent screw tips protruding past the dorsal cortex. The valley in the intermediate column between Lister tubercle and the sigmoid notch of the distal radius makes it difficult to rely on fluoroscopy to judge screw length. Our aim was to quantify the dimensions of this valley and to demonstrate the danger of relying on intraoperative image intensification fluoroscopy to determine lengths of distal screws. We measured the depth of this valley in the intermediate column of the distal radius in 33 patients with computed tomographic (9 patients) or magnetic resonance image (24 patients) scans of the wrist. There was a consistent valley in all images examined [average 1.8 mm (95% confidence interval, 1.6-2.0 mm)]. Thirty-nine percent of wrists had a valley depth of at least 2 mm. Standard lateral views or rotation of the forearm to obtain oblique views does not identify prominent screw tips; and whatever the rotation of the forearm, screw tips protruding beyond dorsal cortex may look as if it is within the bone when in fact it is out. When drilling we suggest noting the depth at which the drill bit just penetrates dorsal cortex and routinely downsize the distal screw length by 2 mm. We caution against relying on flourosocopy when judging the length of the distal subchondral screws.

Cumulative total effective whole-body radiation dose in critically ill patients.

PubMed

Rohner, Deborah J; Bennett, Suzanne; Samaratunga, Chandrasiri; Jewell, Elizabeth S; Smith, Jeffrey P; Gaskill-Shipley, Mary; Lisco, Steven J

2013-11-01

Uncertainty exists about a safe dose limit to minimize radiation-induced cancer. Maximum occupational exposure is 20 mSv/y averaged over 5 years with no more than 50 mSv in any single year. Radiation exposure to the general population is less, but the average dose in the United States has doubled in the past 30 years, largely from medical radiation exposure. We hypothesized that patients in a mixed-use surgical ICU (SICU) approach or exceed this limit and that trauma patients were more likely to exceed 50 mSv because of frequent diagnostic imaging. Patients admitted into 15 predesignated SICU beds in a level I trauma center during a 30-day consecutive period were prospectively observed. Effective dose was determined using Huda's method for all radiography, CT imaging, and fluoroscopic examinations. Univariate and multivariable linear regressions were used to analyze the relationships between observed values and outcomes. Five of 74 patients (6.8%) exceeded exposures of 50 mSv. Univariate analysis showed trauma designation, length of stay, number of CT scans, fluoroscopy minutes, and number of general radiographs were all associated with increased doses, leading to exceeding occupational exposure limits. In a multivariable analysis, only the number of CT scans and fluoroscopy minutes remained significantly associated with increased whole-body radiation dose. Radiation levels frequently exceeded occupational exposure standards. CT imaging contributed the most exposure. Health-care providers must practice efficient stewardship of radiologic imaging in all critically ill and injured patients. Diagnostic benefit must always be weighed against the risk of cumulative radiation dose.

Fast 3-T MR-guided transrectal prostate biopsy using an in-room tablet device for needle guide alignment: a feasibility study.

PubMed

Overduin, Christiaan G; Heidkamp, Jan; Rothgang, Eva; Barentsz, Jelle O; de Lange, Frank; Fütterer, Jurgen J

2018-05-22

To assess the feasibility of adding a tablet device inside the scanner room to assist needle-guide alignment during magnetic resonance (MR)-guided transrectal prostate biopsy. Twenty patients with one cancer-suspicious region (CSR) with PI-RADS score ≥ 4 on diagnostic multiparametric MRI were prospectively enrolled. Two orthogonal scan planes of an MR fluoroscopy sequence (~3 images/s) were aligned to the CSR and needle-guide pivoting point. Targeting was achieved by manipulating the needle-guide under MR fluoroscopy feedback on the in-room tablet device. Technical feasibility and targeting success were assessed. Complications and biopsy procedure times were also recorded. Needle-guide alignment with the in-room tablet device was technically successful in all patients and allowed sampling after a single alignment step in 19/20 (95%) CSRs (median size 14 mm, range: 4-45). Biopsy cores contained cancer in 18/20 patients. There were no per-procedural or post-biopsy complications. Using the tablet device, the mean time to first biopsy was 5.8 ± 1.0 min and the mean total procedure time was 23.7 ± 4.1 min. Use of an in-room tablet device to assist needle-guide alignment was feasible and safe during MR-guided transrectal prostate biopsy. Initial experience indicates potential for procedure time reduction. • Performing MR-guided prostate biopsy using an in-room tablet device is feasible. • CSRs could be sampled after a single alignment step in 19/20 patients. • The mean procedure time for biopsy with the tablet device was 23.7 min.

Overview of epidemiologic studies of radiation and cancer risk based on medical series

DOE Office of Scientific and Technical Information (OSTI.GOV)

Howe, G.R.

1997-03-01

Epidemiologic studies of individuals exposed to ionizing radiation for medical reasons have made important contributions to understanding of the relationship between such radiation and subsequent cancer risk. In this paper the strengths and limitations of medical studies are considered and their future potential usefulness is discussed. Studies may be broadly classified into two types, namely, those of individuals exposed for therapeutic purposes such as the study of ankylosing spondylytics and those of individuals exposed for diagnostic or examination purposes such as those of tuberculosis patients routinely examined by chest fluoroscopy. In general, studies of therapeutic exposures tend to involve highmore » doses of radiation given at high dose rates and in a relatively small number of fractions, whereas studies of diagnostic exposures tend to involve relatively low doses, low dose rates and many fractions. However, these generalizations are not always true: for example, in the fluoroscopy studies some patients received doses to organs such as breast and lung which were substantially higher than those experienced in the atomic bomb survivors study and in a study of Israeli children treated with radiation for tinea capitis the average thyroid dose was reported to be low, and only about 0.09 gray. These studies illustrate one of the most important advantages of medical series, namely the variety of such studies in terms of the characteristics of the radiation involved (linear energy transfer characteristics, dose range, dose rate, and fractionation), the organs exposed and hence potentially at risk, and the characteristics of those exposed to such radiation.« less

Efficient feature-based 2D/3D registration of transesophageal echocardiography to x-ray fluoroscopy for cardiac interventions

NASA Astrophysics Data System (ADS)

Hatt, Charles R.; Speidel, Michael A.; Raval, Amish N.

2014-03-01

We present a novel 2D/ 3D registration algorithm for fusion between transesophageal echocardiography (TEE) and X-ray fluoroscopy (XRF). The TEE probe is modeled as a subset of 3D gradient and intensity point features, which facilitates efficient 3D-to-2D perspective projection. A novel cost-function, based on a combination of intensity and edge features, evaluates the registration cost value without the need for time-consuming generation of digitally reconstructed radiographs (DRRs). Validation experiments were performed with simulations and phantom data. For simulations, in silica XRF images of a TEE probe were generated in a number of different pose configurations using a previously acquired CT image. Random misregistrations were applied and our method was used to recover the TEE probe pose and compare the result to the ground truth. Phantom experiments were performed by attaching fiducial markers externally to a TEE probe, imaging the probe with an interventional cardiac angiographic x-ray system, and comparing the pose estimated from the external markers to that estimated from the TEE probe using our algorithm. Simulations found a 3D target registration error of 1.08(1.92) mm for biplane (monoplane) geometries, while the phantom experiment found a 2D target registration error of 0.69mm. For phantom experiments, we demonstrated a monoplane tracking frame-rate of 1.38 fps. The proposed feature-based registration method is computationally efficient, resulting in near real-time, accurate image based registration between TEE and XRF.

Evaluation of diaphragmatic motion in normal and diaphragmatic paralyzed dogs using M-mode ultrasonography.

PubMed

Choi, Mihyun; Lee, Namsoon; Kim, Ahyoung; Keh, Seoyeon; Lee, Jinsoo; Kim, Hyunwook; Choi, Mincheol

2014-01-01

Diagnosis of unilateral diaphragmatic paralysis in dogs is currently based on fluoroscopic detection of unequal movement between the crura. Bilateral paralysis may be more difficult to confirm with fluoroscopy because diaphragmatic movement is sometimes produced by compensatory abdominal muscle contractions. The purpose of this study was to develop a new method to evaluate diaphragmatic movement using M-mode ultrasonography and to describe findings for normal and diaphragmatic paralyzed dogs. Fifty-five clinically normal dogs and two dogs with diaphragmatic paralysis were recruited. Thoracic radiographs were acquired for all dogs and fluoroscopy studies were also acquired for clinically affected dogs. Two observers independently measured diaphragmatic direction of motion and amplitude of excursion using M-mode ultrasonography for dogs meeting study inclusion criteria. Eight of the clinically normal dogs were excluded due to abnormal thoracic radiographic findings. For the remaining normal dogs, the lower limit values of diaphragmatic excursion were 2.85-2.98 mm during normal breathing. One dog with bilateral diaphragmatic paralysis showed paradoxical movement of both crura at the end of inspiration. One dog with unilateral diaphragmatic paralysis had diaphragmatic excursion values of 2.00 ± 0.42 mm on the left side and 4.05 ± 1.48 mm on the right side. The difference between left and right diaphragmatic excursion values was 55%. Findings indicated that M-mode ultrasonography is a relatively simple and objective method for measuring diaphragmatic movement in dogs. Future studies are needed in a larger number of dogs with diaphragmatic paralysis to determine the diagnostic sensitivity of this promising new technique. © 2013 American College of Veterinary Radiology.

In vitro quantification of the performance of model-based mono-planar and bi-planar fluoroscopy for 3D joint kinematics estimation.

PubMed

Tersi, Luca; Barré, Arnaud; Fantozzi, Silvia; Stagni, Rita

2013-03-01

Model-based mono-planar and bi-planar 3D fluoroscopy methods can quantify intact joints kinematics with performance/cost trade-off. The aim of this study was to compare the performances of mono- and bi-planar setups to a marker-based gold-standard, during dynamic phantom knee acquisitions. Absolute pose errors for in-plane parameters were lower than 0.6 mm or 0.6° for both mono- and bi-planar setups. Mono-planar setups resulted critical in quantifying the out-of-plane translation (error < 6.5 mm), and bi-planar in quantifying the rotation along bone longitudinal axis (error < 1.3°). These errors propagated to joint angles and translations differently depending on the alignment of the anatomical axes and the fluoroscopic reference frames. Internal-external rotation was the least accurate angle both with mono- (error < 4.4°) and bi-planar (error < 1.7°) setups, due to bone longitudinal symmetries. Results highlighted that accuracy for mono-planar in-plane pose parameters is comparable to bi-planar, but with halved computational costs, halved segmentation time and halved ionizing radiation dose. Bi-planar analysis better compensated for the out-of-plane uncertainty that is differently propagated to relative kinematics depending on the setup. To take its full benefits, the motion task to be investigated should be designed to maintain the joint inside the visible volume introducing constraints with respect to mono-planar analysis.

Use of Intracardiac Echocardiography in Interventional Cardiology: Working With the Anatomy Rather Than Fighting It.

PubMed

Enriquez, Andres; Saenz, Luis C; Rosso, Raphael; Silvestry, Frank E; Callans, David; Marchlinski, Francis E; Garcia, Fermin

2018-05-22

The indications for catheter-based structural and electrophysiological procedures have recently expanded to more complex scenarios, in which an accurate definition of the variable individual cardiac anatomy is key to obtain optimal results. Intracardiac echocardiography (ICE) is a unique imaging modality able to provide high-resolution real-time visualization of cardiac structures, continuous monitoring of catheter location within the heart, and early recognition of procedural complications, such as pericardial effusion or thrombus formation. Additional benefits are excellent patient tolerance, reduction of fluoroscopy time, and lack of need for general anesthesia or a second operator. For these reasons, ICE has largely replaced transesophageal echocardiography as ideal imaging modality for guiding certain procedures, such as atrial septal defect closure and catheter ablation of cardiac arrhythmias, and has an emerging role in others, including mitral valvuloplasty, transcatheter aortic valve replacement, and left atrial appendage closure. In electrophysiology procedures, ICE allows integration of real-time images with electroanatomic maps; it has a role in assessment of arrhythmogenic substrate, and it is particularly useful for mapping structures that are not visualized by fluoroscopy, such as the interatrial or interventricular septum, papillary muscles, and intracavitary muscular ridges. Most recently, a three-dimensional (3D) volumetric ICE system has also been developed, with potential for greater anatomic information and a promising role in structural interventions. In this state-of-the-art review, we provide guidance on how to conduct a comprehensive ICE survey and summarize the main applications of ICE in a variety of structural and electrophysiology procedures. © 2018 American Heart Association, Inc.

Current applications of robotics in spine surgery: a systematic review of the literature.

PubMed

Joseph, Jacob R; Smith, Brandon W; Liu, Xilin; Park, Paul

2017-05-01

OBJECTIVE Surgical robotics has demonstrated utility across the spectrum of surgery. Robotics in spine surgery, however, remains in its infancy. Here, the authors systematically review the evidence behind robotic applications in spinal instrumentation. METHODS This systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Relevant studies (through October 2016) that reported the use of robotics in spinal instrumentation were identified from a search of the PubMed database. Data regarding the accuracy of screw placement, surgeon learning curve, radiation exposure, and reasons for robotic failure were extracted. RESULTS Twenty-five studies describing 2 unique robots met inclusion criteria. Of these, 22 studies evaluated accuracy of spinal instrumentation. Although grading of pedicle screw accuracy was variable, the most commonly used method was the Gertzbein and Robbins system of classification. In the studies using the Gertzbein and Robbins system, accuracy (Grades A and B) ranged from 85% to 100%. Ten studies evaluated radiation exposure during the procedure. In studies that detailed fluoroscopy usage, overall fluoroscopy times ranged from 1.3 to 34 seconds per screw. Nine studies examined the learning curve for the surgeon, and 12 studies described causes of robotic failure, which included registration failure, soft-tissue hindrance, and lateral skiving of the drill guide. CONCLUSIONS Robotics in spine surgery is an emerging technology that holds promise for future applications. Surgical accuracy in instrumentation implanted using robotics appears to be high. However, the impact of robotics on radiation exposure is not clear and seems to be dependent on technique and robot type.

Treatment of Die-Punch Fractures with 3D Printing Technology.

PubMed

Chen, Chunhui; Cai, Leyi; Zhang, Chuanxu; Wang, Jianshun; Guo, Xiaoshan; Zhou, Yifei

2017-07-19

We evaluated the feasibility, accuracy and effectiveness of applying three-dimensional (3D) printing technology for preoperative planning for die-punch fractures. A total of 107 patients who underwent die-punch fracture surgery were enrolled in the study. They were randomly divided into two groups: 52 cases in the 3D model group and 55 cases in the routine group. A 3D digital model of each die-punch fracture was reconstructed in the 3D group. The 3D digital model was imported to a 3D printer to build the full solid model. The operation time, blood loss volume, and the number of intraoperative fluoroscopy were recorded. Follow-up was performed to evaluate the patients' surgical outcomes. Treatment of die-punch fractures using the 3D printing approach reduced the number of intraoperative fluoroscopy, blood loss volume, and operation time, but did not improve wrist function compared to those in the routine group. The patients wanted the doctor to use the 3D model to introduce the condition and operative plan because it was easier for them to understand. The orthopedic surgeons thought that the 3D model was useful for communicating with their patients, but their satisfaction with the preoperative plan was much lower than the benefit of using the 3D model to communicate with their patients. 3D printing technology produced more accurate morphometric information for orthopedists to provide personalized surgical planning and communicate better with their patients. However, it is difficult to use widely in the department of orthopedics.

A Comparison of Retrograde Intrarenal Surgery and Percutaneous Nephrolithotomy for Management of Renal Stones ?2 CM.

PubMed

Sari, Sercan; Ozok, Hakki Ugur; Cakici, Mehmet Caglar; Ozdemir, Harun; Bas, Okan; Karakoyunlu, Nihat; Sagnak, Levent; Senturk, Aykut Bugra; Ersoy, Hamit

2017-01-18

In this retrospective study, we aimed to compare the outcomes in patients who have been treated withpercutaneous nephrolithotomy (PNL) and retrograde intrarenal surgery (RIRS) on renal stones ≥ 2 cm size. We evaluated patients who underwent PNL or RIRS for renal stones ≥ 2 cm size betweenNovember 2011 and November 2014. Stone size, operation, fluoroscopy and hospitalization time, success rates,stone-free rates and complication rates were compared in both groups. Patients were followed for three months. 254 patients were in the PNL Group. 185 patients were in the RIRS Group. The mean age was 46.88 and48.04 years in PNL and RIRS groups, respectively.The patient and stone characteristics (age, gender, Body Mass Index, kidney anomaly, SWL history and stoneradioopacity) were similar between two groups.The mean stone size preoperatively was significantly larger in patients who were treated with PNL (26.33mm.vs24.04mm.; P = .006). In the RIRS group, the mean stone number was significantly higher than PNL group (P <.001).The mean operative, fluoroscopy and hospitalization time were significantly higher in PNL group (P < .001). Thestone-free rate was 93.3% for the PNL group and 73.5% for the RIRS group after first procedure (P < .001). Nomajor complication (Clavien III-V) occurred in the RIRS group. Although the primary treatment method for renal stones ≥ 2cm size is PNL, serious complicationscan be seen. Therefore, RIRS can be an alternative treatment option in the management of renal stones ≥2 cm size.

Truly hybrid interventional MR/X-ray system: investigation of in vivo applications.

PubMed

Fahrig, R; Butts, K; Wen, Z; Saunders, R; Kee, S T; Sze, D Y; Daniel, B L; Laerum, F; Pelc, N J

2001-12-01

The purpose of this study was to provide in vivo demonstrations of the functionality of a truly hybrid interventional x-ray/magnetic resonance (MR) system. A digital flat-panel x-ray system (1,024(2) array of 200 microm pixels, 30 frames per second) was integrated into an interventional 0.5-T magnet. The hybrid system is capable of MR and x-ray imaging of the same field of view without patient movement. Two intravascular procedures were performed in a 22-kg porcine model: placement of a transjugular intrahepatic portosystemic shunt (TIPS) (x-ray-guided catheterization of the hepatic vein, MR fluoroscopy-guided portal puncture, and x-ray-guided stent placement) and mock chemoembolization (x-ray-guided subselective catheterization of a renal artery branch and MR evaluation of perfused volume). The resolution and frame rate of the x-ray fluoroscopy images were sufficient to visualize and place devices, including nitinol guidewires (0.016-0.035-inch diameter) and stents and a 2.3-F catheter. Fifth-order branches of the renal artery could be seen. The quality of both real-time (3.5 frames per second) and standard MR images was not affected by the x-ray system. During MR-guided TIPS placement, the trocar and the portal vein could be easily visualized, allowing successful puncture from hepatic to portal vein. Switching back and forth between x-ray and MR imaging modalities without requiring movement of the patient was demonstrated. The integrated nature of the system could be especially beneficial when x-ray and MR image guidance are used iteratively.

Utility of Adjunctive Digital Subtraction Venography for the Treatment of Saphenous Vein Insufficiency.

PubMed

Varcoe, Ramon L; Thomas, Shannon D; Bourke, Victor; Rübesamen, Nicole M K; Lennox, Andrew F

2017-04-01

To report the use of adjunctive venography for the treatment of superficial venous reflux. Two hundred consecutive patients (mean age 60.9 years, range 33-86; 128 women) with chronic venous disease underwent saphenous or perforator vein ablation in 268 limbs (305 venous trunks) guided by adjunctive venography and fluoroscopy in addition to ultrasound between October 2010 and May 2016. Intraprocedural venograms were independently evaluated by 2 vascular specialists to identify the presence of venous anomalies and the need for fluoroscopy-guided maneuvers to successfully complete venous ablation. Intraprocedural venography results were compared with preoperative venous duplex scan reports to ascertain if the duplex study could be of value in identifying preoperatively any anatomical variants that may pose a technical challenge to the operator. In this cohort, 542 venograms (2.0/limb) were performed with a mean duration of 4.9±9.1 minutes (range 1-48). Two thirds of patients (132, 66%) had anomalies or abnormalities within the target vein; more than a third (88, 44%) required an endovascular maneuver to successfully complete the ablation and 17% (34) of cases were impossible to complete without adjunctive fluoroscopic guidance. Per-patient comparison of intraprocedural venography with preoperative venous duplex reports identified 21 (11%) patients with abnormalities detected on ultrasound (23 anomalies) compared with 123 (64%) on venography (193 anomalies). This gave ultrasound a 17.1% sensitivity, 100% specificity and positive predictive value, and 40.7% negative predictive value. Venography is a valuable addition to ultrasound to facilitate complete ablation of insufficient saphenous veins in selected patients with complex anatomy.

Single Center Retrospective Analysis of Conventional and Radial TIG Catheters for Transradial Diagnostic Coronary Angiography

PubMed Central

Vorpahl, Marc; Koehler, Till; Foerst, Jason; Panagiotopoulos, Spyridon; Schleiting, Heinrich; Koss, Klaus; Ziegler, Gunda; Brinkmann, Hilmar; Seyfarth, Melchior; Tiroch, Klaus

2015-01-01

Current guidelines favor the radial approach for coronary angiography. Therefore, specialty radial diagnostic catheters were designed to engage both coronary arteries with a single device. However, it is unclear if single catheters are superior to conventional catheters. A retrospective analysis was performed of consecutive right radial coronary angiographies to determine catheter use, fluoroscopy time, radiation dosage, and consumption of contrast. Procedures were performed with a single TIG catheter or conventional catheters (CONV). Procedures with coronary artery bypass grafts or ventricular angiographies were excluded. 273 transradial procedures were performed successfully. 95 procedures were performed with CONV and 178 procedures with a TIG. Crossover to additional catheters was higher in TIG (15.2%) compared to CONV (5.3%, p = 0.02). Fluoroscopy time was comparable between CONV and TIG, without crossover (2.2 ± 1.2 min versus 2.3 ± 1.2 min; n.s.), however, greater in the case of crossover for CONV (5.8 ± 0.7) and TIG (7.6 ± 3.0; p = 0.0001). Radiation dosage was similar in CONV and the TIG, without crossover (1419 ± 1075, cGy∗cm2 versus 1690 ± 1138; n.s.), however, greater for CONV (2374 ± 620) and TIG (3733 ± 2281, p = 0.05) with crossover. Overall, the amount of contrast was greater in TIG (56 ± 13 mL) versus CONV (48 ± 3 mL; p = 0.0003). CONV femoral catheters may be the primary choice for radial approach. PMID:26435876

Preliminary Experience with use of Qureshi-5 Catheters for Diagnostic Cerebral Angiography

PubMed Central

Qureshi, Adnan I.; Yan, Xiao; Liu, HongLiang

2015-01-01

BACKGROUND A catheter technique was developed to overcome current challenges in the stabilization and manipulation of catheter in tortuous arteries such as right subclavian artery and left common carotid artery. METHODS The new catheter has the following two lumens: first lumen can accommodate a 0.035-inch guide wire (lumen A) and a curved shape at the distal end; the second lumen can accommodate a 0.018-inch guide wire and terminates at the beginning of the distal curve of the first lumen (lumen B). The catheter is withdrawn or advanced over the 0.018-inch guide wire and the curved free end of catheter manipulated until the end engages the origin of the target artery. Subsequently, either contrast can be injected or a 0.035-inch guide wire advanced into the target artery. RESULTS The catheters were used in two patients to perform diagnostic cerebral angiography through a 6F introducer sheath placed in the right common femoral artery. The left and right common carotid arteries and left and right vertebral arteries were catheterized in first patient (contrast used 50 ml; fluoroscopy time 20:09 min). The left and right internal carotid arteries, left and right subclavian arteries, and left external carotid artery were catheterized in second patient (contrast used 40 ml; fluoroscopy time 13:56 min). No complications were observed in either of the two patients. CONCLUSIONS The performance of the new catheter for catheterization of multiple arteries in two patients was considered adequate with high-quality angiographic image acquisitions. PMID:26060529

Medical personnel and patient dosimetry during coronary angiography and intervention

NASA Astrophysics Data System (ADS)

Efstathopoulos, Efstathios P.; Makrygiannis, Stamatis S.; Kottou, Sofia; Karvouni, Evangelia; Giazitzoglou, Eleftherios; Korovesis, Socrates; Tzanalaridou, Efthalia; Raptou, Panagiota D.; Katritsis, Demosthenes G.

2003-09-01

Percutaneous coronary interventions are associated with increased radiation exposure compared to most radiological examinations. This prospective study aimed at (1) measuring entrance doses for all in-room personnel, (2) performing an assessment of patient effective dose and intracoronary doses, (3) investigating the contribution of each projection to kerma-area product (KAP) and irradiation time, (4) comparing results with established DRL values in this clinical setting and (5) estimating the risk for fatal cancer to patients and operators. Measurements were performed during 40 consecutive procedures of coronary angiography (CA), half of which were followed by ad hoc coronary angioplasty (PTCA). KAP measurements were used for patients and thermoluminescent dosimetry for the in-room personnel. The mean KAP value per procedure for CA was 29 +/- 9 Gy cm2. Thirty four per cent of KAP was due to fluoroscopy, whereas the remainder (66%) was due to digital cine. Accordingly, the mean KAP value per PTCA procedure was 75 +/- 30 Gy cm2, and contribution of fluoroscopy is 57%. Effective dose per year was estimated to be 0.04-0.05 mSv y-1 for the primary operator, and 0.03-0.04 mSv y-1 for those assisting. Corresponding measurements for radiographer and nurse were below detectable level, implying minimal radiation hazards for them. Regarding radiation exposure, coronary intervention is considered a quite safe procedure for both patients and personnel in laboratories with modern equipment and experienced operators as long as standard safety precautions are considered. Exposure optimization though should be constantly sought through continuous review of procedures.

Fluoroscopy-Guided Sacroiliac Intraarticular Injection via the Middle Portion of the Joint.

PubMed

Kurosawa, Daisuke; Murakami, Eiichi; Aizawa, Toshimi

2017-09-01

Sacroiliac intraarticular injection is necessary to confirm sacroiliac joint (SIJ) pain and is usually performed via the caudal one-third portion of the joint. However, this is occasionally impossible for anatomical reasons, and the success rate is low in clinical settings. We describe a technique via the middle portion of the joint. Observational study. Enrolled were 69 consecutive patients (27 men and 42 women, with an average age of 53 years) in whom the middle portion of 100 joints was targeted. With the patient lying prone-oblique with the painful side down, a spinal needle was inserted into the middle portion of the joint. Subsequently, the fluoroscopy tube was angled at a caudal tilt of 25-30° to clearly detect the recess between the ilium and sacrum and the needle depth and direction. When the needle reached the posterior joint line, 2% lidocaine was injected after the contrast medium outlined the joint. The success rate of the injection method was 80% (80/100). Among 80 successful cases, four were previously unsuccessful when the conventional method was used. Intraarticular injection using the new technique was unsuccessful in 20 joints; in three of these cases, the conventional method proved successful, and no techniques were successful in the other 17 cases. The injection technique via the middle portion of the joint can overcome some of the difficulties of the conventional injection method and can improve the chances of successful intraarticular injection. © 2016 American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

Training safer orthopedic surgeons. Construct validation of a virtual-reality simulator for hip fracture surgery.

PubMed

Akhtar, Kashif; Sugand, Kapil; Sperrin, Matthew; Cobb, Justin; Standfield, Nigel; Gupte, Chinmay

2015-01-01

Virtual-reality (VR) simulation in orthopedic training is still in its infancy, and much of the work has been focused on arthroscopy. We evaluated the construct validity of a new VR trauma simulator for performing dynamic hip screw (DHS) fixation of a trochanteric femoral fracture. 30 volunteers were divided into 3 groups according to the number of postgraduate (PG) years and the amount of clinical experience: novice (1-4 PG years; less than 10 DHS procedures); intermediate (5-12 PG years; 10-100 procedures); expert (> 12 PG years; > 100 procedures). Each participant performed a DHS procedure and objective performance metrics were recorded. These data were analyzed with each performance metric taken as the dependent variable in 3 regression models. There were statistically significant differences in performance between groups for (1) number of attempts at guide-wire insertion, (2) total fluoroscopy time, (3) tip-apex distance, (4) probability of screw cutout, and (5) overall simulator score. The intermediate group performed the procedure most quickly, with the lowest fluoroscopy time, the lowest tip-apex distance, the lowest probability of cutout, and the highest simulator score, which correlated with their frequency of exposure to running the trauma lists for hip fracture surgery. This study demonstrates the construct validity of a haptic VR trauma simulator with surgeons undertaking the procedure most frequently performing best on the simulator. VR simulation may be a means of addressing restrictions on working hours and allows trainees to practice technical tasks without putting patients at risk. The VR DHS simulator evaluated in this study may provide valid assessment of technical skill.

Three-dimensional fluoroscopic navigation-assisted surgery for tumors in patients with tumor-induced osteomalacia in the bones.

PubMed

Kobayashi, Hiroshi; Akiyama, Toru; Okuma, Tomotake; Shinoda, Yusuke; Oka, Hiroyuki; Ito, Nobuaki; Fukumoto, Seiji; Tanaka, Sakae; Kawano, Hirotaka

2017-12-01

Tumor-induced osteomalacia (TIO) is a rare paraneoplastic syndrome usually caused by phosphaturic mesenchymal tumors. Segmental resection has been recommended for these tumors in the bones because curettage was found to be associated with a high local recurrence rate. Navigation-assisted surgery provides radiological information to guide the surgeon during surgery. No previous study has reported on the efficacy of navigation-assisted surgery for tumors in patients with TIO. Therefore, the present study aimed to evaluate the efficacy of navigation-assisted surgery for tumors in patients with TIO. The study included seven patients with TIO who were treated between January 2003 and December 2014 at our hospital. All patients underwent surgical treatment with or without the use of a 3-dimensional (3D) fluoroscopy-based navigation system. The laboratory data and oncological outcomes were evaluated. The follow-up period was 8-128 months. The tumors were located at the femur (n = 4), ischium, spine and ilium (n = 1). Of the seven patients, five underwent navigation-assisted surgery and two underwent surgery without navigation assistance. In the two patients who underwent surgery without navigation assistance, a complete cure was not obtained and osteomalacia did not resolve. One of these two patients and the other five patients who underwent navigation-assisted surgery, one patient had incomplete resection due to massive invasion of the tumor into the spinal canal, but five patients achieved complete excision and recovered from osteomalacia. Navigation-assisted surgery using a 3D fluoroscopy-based navigation system is effective for tumors in patients with TIO.

Radiation safety in the cardiac catheterization lab: A time series quality improvement initiative.

PubMed

Abuzeid, Wael; Abunassar, Joseph; Leis, Jerome A; Tang, Vicky; Wong, Brian; Ko, Dennis T; Wijeysundera, Harindra C

Interventional cardiologists have one of the highest annual radiation exposures yet systems of care that promote radiation safety in cardiac catheterization labs are lacking. This study sought to reduce the frequency of radiation exposure, for PCI procedures, above 1.5Gy in labs utilizing a Phillips system at our local institution by 40%, over a 12-month period. We performed a time series study to assess the impact of different interventions on the frequency of radiation exposure above 1.5Gy. Process measures were percent of procedures where collimation and magnification were used and percent of completion of online educational modules. Balancing measures were the mean number of cases performed and mean fluoroscopy time. Information sessions, online modules, policies and posters were implemented followed by the introduction of a new lab with a novel software (AlluraClarity©) to reduce radiation dose. There was a significant reduction (91%, p<0.05) in the frequency of radiation exposure above 1.5Gy after utilizing a novel software (AlluraClarity©) in a new Phillips lab. Process measures of use of collimation (95.0% to 98.0%), use of magnification (20.0% to 14.0%) and completion of online modules (62%) helped track implementation. The mean number of cases performed and mean fluoroscopy time did not change significantly. While educational strategies had limited impact on reducing radiation exposure, implementing a novel software system provided the most effective means of reducing radiation exposure. Crown Copyright © 2017. Published by Elsevier Inc. All rights reserved.

Teaching basic trauma: validating FluoroSim, a digital fluoroscopic simulator for guide-wire insertion in hip surgery.

PubMed

Sugand, Kapil; Wescott, Robert A; Carrington, Richard; Hart, Alister; Van Duren, Bernard H

2018-05-10

Background and purpose - Simulation is an adjunct to surgical education. However, nothing can accurately simulate fluoroscopic procedures in orthopedic trauma. Current options for training with fluoroscopy are either intraoperative, which risks radiation, or use of expensive and unrealistic virtual reality simulators. We introduce FluoroSim, an inexpensive digital fluoroscopy simulator without the need for radiation. Patients and methods - This was a multicenter study with 26 surgeons in which everyone completed 1 attempt at inserting a guide-wire into a femoral dry bone using surgical equipment and FluoroSim. 5 objective performance metrics were recorded in real-time to assess construct validity. The surgeons were categorized based on the number of dynamic hip screws (DHS) performed: novices (< 10), intermediates (10-39) and experts (≥ 40). A 7-point Likert scale questionnaire assessed the face and content validity of FluoroSim. Results - Construct validity was present for 2 clinically validated metrics in DHS surgery. Experts and intermediates statistically significantly outperformed novices for tip-apex distance and for cut-out rate. Novices took the least number of radiographs. Face and content validity were also observed. Interpretation - FluoroSim discriminated between novice and intermediate or expert surgeons based on tip-apex distance and cut-out rate while demonstrating face and content validity. FluoroSim provides a useful adjunct to orthopedic training. Our findings concur with results from studies using other simulation modalities. FluoroSim can be implemented for education easily and cheaply away from theater in a safe and controlled environment.

Persistent Atrial Fibrillation Ablation using the Tip-Versatile Ablation Catheter.

PubMed

Davies, Edward J; Clayton, Ben; Lines, Ian; Haywood, Guy A

2016-07-01

The mechanisms by which persistent atrial fibrillation (PsAF) develops are incompletely understood. Consequently, the optimal strategy for the ablative management of PsAF remains debated. Current methods are often time consuming, complex and non-reproducible. We assessed the Tip-Versatile Ablation Catheter (T-VAC) technique, a rapidly delivered, empirical technique based on the box-set concept using duty-cycled linear catheter ablation technology. Forty-four procedures in 40 patients undergoing PsAF ablation with the novel technique were prospectively entered onto a database: 27 de novo. Primary endpoint was freedom from arrhythmia at over two-year follow-up. Secondary endpoints were time to first arrhythmia recurrence, freedom from atrial fibrillation (AF) on and off antiarrhythmic drugs (AAD), procedural and fluoroscopy duration and complication rate. At mean follow-up of 33 months, absolute freedom from arrhythmia recurrence was 45% in the de novo group. Overall, at 33 (IQR 24-63) months, 60% of de novo patients were in sustained normal sinus rhythm and a further 15% reported only occasional paroxysms of AF at long-term follow-up. Procedure time was 192±25 mins, total energy delivered 2239±883s and fluoroscopy time was 60±10mins. In selected patients with persistent AF, a long-term rate of 60% arrhythmia free survival off AAD can be achieved using this novel T-VAC technique. Copyright © 2016 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.

A new software tool for 3D motion analyses of the musculo-skeletal system.

PubMed

Leardini, A; Belvedere, C; Astolfi, L; Fantozzi, S; Viceconti, M; Taddei, F; Ensini, A; Benedetti, M G; Catani, F

2006-10-01

Many clinical and biomechanical research studies, particularly in orthopaedics, nowadays involve forms of movement analysis. Gait analysis, video-fluoroscopy of joint replacement, pre-operative planning, surgical navigation, and standard radiostereometry would require tools for easy access to three-dimensional graphical representations of rigid segment motion. Relevant data from this variety of sources need to be organised in structured forms. Registration, integration, and synchronisation of segment position data are additional necessities. With this aim, the present work exploits the features of a software tool recently developed within a EU-funded project ('Multimod') in a series of different research studies. Standard and advanced gait analysis on a normal subject, in vivo fluoroscopy-based three-dimensional motion of a replaced knee joint, patellar and ligament tracking on a knee specimen by a surgical navigation system, stem-to-femur migration pattern on a patient operated on total hip replacement, were analysed with standard techniques and all represented by this innovative software tool. Segment pose data were eventually obtained from these different techniques, and were successfully imported and organised in a hierarchical tree within the tool. Skeletal bony segments, prosthesis component models and ligament links were registered successfully to corresponding marker position data for effective three-dimensional animations. These were shown in various combinations, in different views, from different perspectives, according to possible specific research interests. Bioengineering and medical professionals would be much facilitated in the interpretation of the motion analysis measurements necessary in their research fields, and would benefit therefore from this software tool.

Rates of Upper Facet Joint Violation in Minimally Invasive Percutaneous and Open Instrumentation: A Comparative Cohort Study of Different Insertion Techniques.

PubMed

Archavlis, Eleftherios; Amr, Nimer; Kantelhardt, Sven Rainer; Giese, Alf

2018-01-01

 Minimally invasive pedicle screw placement may have a higher incidence of violation of the superior cephalad unfused facet joint.  We investigated the incidence and risk factors of upper facet joint violation in percutaneous robot-assisted instrumentation versus percutaneous fluoroscopy-guided and open transpedicular instrumentation.  A retrospective study including all consecutive patients who underwent lumbar instrumentation, fusion, and decompression for spondylolisthetic stenosis and degenerative disk disease was conducted between January 2012 and January 2016. All operations were performed by the same surgeon; the patients were divided into three groups according to the method of instrumentation. Group 1 involved the robot-assisted instrumentation in 58 patients, group 2 consisted of 64 patients treated with a percutaneous transpedicular instrumentation using fluoroscopic guidance, and 72 patients in group 3 received an open midline approach for pedicle screw insertion.  Superior segment facet joint violation occurred in 2 patients in the robot-assisted group 1 (7%), in 22 of the percutaneous fluoroscopy-guided group 2 (34%), and in 6 cases of the open group (8%). The incidence of facet joint violation was present in 5% (3) of the screws in group 1, 22% (28) of the screws in group 2, and 3% (4) of the screws in group 3.  Meticulous surgical planning of the appropriate entry site (Weinstein's method), trajectory planning, and proper robot-assisted instrumentation of pedicle screws reduced the risk of superior segment facet joint violation. Georg Thieme Verlag KG Stuttgart · New York.

High dynamic range pixel architecture for advanced diagnostic medical x-ray imaging applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Izadi, Mohammad Hadi; Karim, Karim S.

2006-05-15

The most widely used architecture in large-area amorphous silicon (a-Si) flat panel imagers is a passive pixel sensor (PPS), which consists of a detector and a readout switch. While the PPS has the advantage of being compact and amenable toward high-resolution imaging, small PPS output signals are swamped by external column charge amplifier and data line thermal noise, which reduce the minimum readable sensor input signal. In contrast to PPS circuits, on-pixel amplifiers in a-Si technology reduce readout noise to levels that can meet even the stringent requirements for low noise digital x-ray fluoroscopy (<1000 noise electrons). However, larger voltagesmore » at the pixel input cause the output of the amplified pixel to become nonlinear thus reducing the dynamic range. We reported a hybrid amplified pixel architecture based on a combination of PPS and amplified pixel designs that, in addition to low noise performance, also resulted in large-signal linearity and consequently higher dynamic range [K. S. Karim et al., Proc. SPIE 5368, 657 (2004)]. The additional benefit in large-signal linearity, however, came at the cost of an additional pixel transistor. We present an amplified pixel design that achieves the goals of low noise performance and large-signal linearity without the need for an additional pixel transistor. Theoretical calculations and simulation results for noise indicate the applicability of the amplified a-Si pixel architecture for high dynamic range, medical x-ray imaging applications that require switching between low exposure, real-time fluoroscopy and high-exposure radiography.« less

Rotational Angiography Based Three-Dimensional Left Atrial Reconstruction: A New Approach for Transseptal Puncture.

PubMed

Koektuerk, Buelent; Yorgun, Hikmet; Koektuerk, Oezlem; Turan, Cem H; Gorr, Eduard; Horlitz, Marc; Turan, Ramazan G

2016-02-01

Rotational angiography is a well-known method for the three-dimensional (3-D) reconstruction of left atrium and pulmonary veins during left-sided atrial arrhythmia ablation procedures. In our study, we aimed to review our experience in transseptal puncture (TSP) using 3-D rotational angiography. We included a total of 271 patients who underwent atrial fibrillation ablation using cryoballoon. Rotational angiography was performed to get the three-dimensional left atrial and pulmonary vein reconstructions using cardiac C-arm computed tomography. The image reconstruction was made using the DynaCT Cardiac software (Siemens, Erlangen, Germany). The mean age of the study population was 61 ± 10 years. The indications for left atrial arrhythmia ablation were paroxysmal AF in 140 patients (52%) and persistent AF patients in 131 (48%) patients. The success rate of TSP using only rotational guidance was (264/271 patients, 97.4%). In the remaining seven patients, transesophageal guidance was used after the initial attempt due to thick interatrial septum in five patients and difficult TSP due to abnormal anatomy and mild pericardial effusion in the remaining two patients. Mean fluoroscopy dosage of the rotational angiography was 4896.4 ± 825.3 μGym(2). The mean time beginning from femoral vein puncture to TSP was 12.3 ± 5.5 min. TSP guided by rotational angiography is a safe and effective method. Our results indicate that integration of rotational angiographic images into the real-time fluoroscopy can guide the TSP during the procedure. © 2015 John Wiley & Sons Ltd.

Alternative radiation-free registration technique for image-guided pedicle screw placement in deformed cervico-thoracic segments.

PubMed

Kantelhardt, Sven R; Neulen, Axel; Keric, Naureen; Gutenberg, Angelika; Conrad, Jens; Giese, Alf

2017-10-01

Image-guided pedicle screw placement in the cervico-thoracic region is a commonly applied technique. In some patients with deformed cervico-thoracic segments, conventional or 3D fluoroscopy based registration of image-guidance might be difficult or impossible because of the anatomic/pathological conditions. Landmark based registration has been used as an alternative, mostly using separate registration of each vertebra. We here investigated a routine for landmark based registration of rigid spinal segments as single objects, using cranial image-guidance software. Landmark based registration of image-guidance was performed using cranial navigation software. After surgical exposure of the spinous processes, lamina and facet joints and fixation of a reference marker array, up to 26 predefined landmarks were acquired using a pointer. All pedicle screws were implanted using image guidance alone. Following image-guided screw placement all patients underwent postoperative CT scanning. Screw positions as well as intraoperative and clinical parameters were retrospectively analyzed. Thirteen patients received 73 pedicle screws at levels C6 to Th8. Registration of spinal segments, using the cranial image-guidance succeeded in all cases. Pedicle perforations were observed in 11.0%, severe perforations of >2 mm occurred in 5.4%. One patient developed a transient C8 syndrome and had to be revised for deviation of the C7 pedicle screw. No other pedicle screw-related complications were observed. In selected patients suffering from pathologies of the cervico-thoracic region, which impair intraoperative fluoroscopy or 3D C-arm imaging, landmark based registration of image-guidance using cranial software is a feasible, radiation-saving and a safe alternative.

Intra-operative localisation of thoracic spine level: a simple "'K'-wire in pedicle" technique.

PubMed

Thambiraj, Sathya; Quraishi, Nasir A

2012-05-01

To describe a simple and reliable method of intra-operative localisation of thoracic spine in a single surgical setting. Intra-operative localisation of thoracic spine levels can be difficult due to anatomical constraints, such as scapular shadow, patient's size and poor bone quality. This is particularly true in cases of thoracic discectomies in which the vertebral bodies appear normal. There are several methods described in recent literature to address this. Many of them require a separate procedure which was performed often the previous day. We report a technique which addresses the issue of localising thoracic level intra-operatively. After induction of general anaesthesia, the patient was placed prone and the pedicle of interest was identified using fluoroscopy. A K-wire was then inserted percutaneously into this pedicle under image guidance [confirmed in the antero-posterior (AP) and lateral views]. The wire was then cut close to the skin after bending it. The patient was now positioned laterally and the intended procedure performed through an anterior trans-thoracic approach. The 'K' wire was removed at the end of the procedure. We routinely used this technique in all our thoracic discectomies (four cases in 2 years). There were no intra-operative complications. This method is simple, avoids the patient undergoing two procedures and requires no more ability than placing an implant in the pedicle under fluoroscopy. Placing the 'K' wire into a fixed point like the pedicle facilitates rapid intra-operative viewing of the level of interest and is removed easily at the conclusion of surgery.

Carotid artery stenting with double cerebral embolic protection in asymptomatic patients - a diffusion-weighted MRI controlled study.

PubMed

Vuruskan, Ertan; Saracoglu, Erhan; Ergun, Ugur; Poyraz, Fatih; Duzen, İrfan Veysel

2017-01-01

The aim of this study was to compare the simultaneous double-protection method (proximal balloon plus distal filter) with distal-filter protection or proximal-balloon protection alone in asymptomatic patients during carotid artery stenting. 119 consecutive patients were investigated for carotid artery stentings in the extracranial internal carotid artery with the use of distal filters (n = 41, 34.4 %), proximal balloon (MoMa) protection (n = 40, 33.6 %) or double protection (n = 38, 31.9 %). Magnetic resonance imaging (MRI) was performed on all patients before the procedure, and control diffusion-weighted MRI (DW-MRI) was obtained within 24-48 h after the procedure. Procedural data, complications, success rate, major adverse cardiovascular events, and MRI findings were collected. New cerebral high-intensity (HI) lesions were observed in 47 (39.4 %) patients. HI lesions were observed in 22 (53.6 %), 15 (37.5 %), and 10 (26.3 %) of the patients with distal filters, proximal protection, and double protection, respectively (p = 0.004). The average number of HI lesions on DW-MRI was 1.80 in the distal-filter group, 0.90 in the proximal-balloon group, and 0.55 in the double-protection group (p < 0.001). Procedure and fluoroscopy times were slightly longer in the double-protection group compared to the distal- or proximal-protection groups (p = 0.001). The double (proximal plus distal) cerebral embolic protection technique is safe and effective for minimizing the risk of cerebral embolization, even in patients with asymptomatic carotid artery stenosis, despite slightly longer procedure and fluoroscopy times.
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Patient-specific rehearsal prior to EVAR: a pilot study.

PubMed

Desender, L; Rancic, Z; Aggarwal, R; Duchateau, J; Glenck, M; Lachat, M; Vermassen, F; Van Herzeele, I

2013-06-01

This study aims to evaluate feasibility, face validity, influence on technical factors and subjective sense of utility of patient-specific rehearsal (PsR) prior to endovascular aortic aneurysm repair (EVAR). A prospective, multicentre pilot study. Patients suitable for EVAR were enrolled and a three-dimensional (3D) model of the patient's anatomy was generated. Less than 24 h prior to the real case, rehearsals were conducted in the laboratory or clinical angiosuite. Technical metrics were recorded during both procedures. A subjective questionnaire was used to evaluate realism, technical and human factor aspects (scale 1-5). Ten patients were enrolled. In one case, the treatment plan was altered based on PsR. In 7/9 patients, the rehearsal significantly altered the optimal C-arm position for the proximal landing zone and an identical fluoroscopy angle was chosen in the real procedure. All team members found the rehearsal useful for selecting the optimal fluoroscopy angle (median 4). The realism of the EVAR procedure simulation was rated highly (median 4). All team members found the PsR useful to prepare the individual team members and the entire team (median 4). PsR for EVAR permits creation of realistic case studies. Subjective evaluation indicates that it may influence optimal C-arm angles and be valuable to prepare the entire team. A randomised controlled trial (RCT) is planned to evaluate how this technology may influence technical and team performance, ultimately leading to improved patient safety. Copyright © 2013 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

Fibrinolytic therapy for mechanical pulmonary valve thrombosis.

PubMed

Khajali, Zahra; Mohammadzadeh, Shabnam; Maleki, Majid; Peighambari, Mohammad Mehdi; Sadeghpoor, Anita; Ghavidel, Alireza; Elahi, Behrad; Mirzaaghayan, Mohammadreza

2015-01-01

Treatment of prosthetic heart valve thrombosis using intravenous thrombolytics, although an acceptable alternative to surgery, is not complication free, and the literature has a dearth of data on the subject. This study analyzed the results of fibrinolytic treatment (FT) among a single-center group of patients with mechanical pulmonary valve thrombosis. Between 2000 and 2013, 23 consecutive patients with 25 episodes of pulmonary valve thrombosis received FT. The diagnosis of mechanical pulmonary valve thrombosis was established by fluoroscopy and echocardiography. Streptokinase (SK) was used in 24 cases and alteplase in 1 case. The FT was continued a second day for 14 patients (58.3%), a third day for 1 patient, and a fourth day for 1 patient. Echocardiography and fluoroscopy were performed every day until improvement of malfunction was achieved. Of the 23 patients, 19 had complete resolution of hemodynamic abnormalities after FT, 1 had partial resolution, and 2 showed no change. No patient had major complications. Five minor complications were detected, namely, fever, nausea, thrombophlebitis, epistaxi, and pain. Seven patients (30%) experienced recurrence of thrombosis, whereas four patients had surgery (biological pulmonary valve replacement) without re-thrombolytic therapy, one patient was treated with Alteplase, one patient received SK, and one patient received intense anticoagulation using heparin and warfarin. Overall, FT had a success rate of 84%. The results indicate that regardless of the time to pulmonary valve replacement and echocardiographic and fluoroscopic findings, FT was effective in most cases of mechanical pulmonary valve thrombosis. The efficacy increased with second-day thrombolytic therapy. Major complications were not common after lytic therapy for mechanical pulmonary valve thrombosis.

Radiofrequency-activated PMMA-augmentation through cannulated pedicle screws: A cadaver study to determine the biomechanical benefits in the osteoporotic spine.

PubMed

Karius, T; Deborre, C; Wirtz, D C; Burger, C; Prescher, A; Fölsch, A; Kabir, K; Pflugmacher, R; Goost, H

2017-01-01

PMMA-augmentation of pedicle screws strengthens the bone-screw-interface reducing cut-out risk. Injection of fluid cement bears a higher risk of extravasation, with difficulty of application because of inconsistent viscosity and limited injection time. To test a new method of cement augmentation of pedicle screws using radiofrequency-activated PMMA, which is suspected to be easier to apply and have less extravasations. Twenty-seven fresh-frozen human cadaver lumbar spines were divided into 18 osteoporotic (BMD ≤ 0.8 g/cm2) and 9 non-osteoporotic (BMD > 0.8 g/cm2) vertebral bodies. Bipedicular cannulated pedicle screws were implanted into the vertebral bodies; right screws were augmented with ultra-high viscosity PMMA, whereas un-cemented left pedicle screws served as negative controls. Cement distribution was controlled with fluoroscopy and CT scans. Axial pullout forces of the screws were measured with a material testing machine, and results were analyzed statistically. Fluoroscopy and CT scans showed that in all cases an adequately big cement depot with homogenous form and no signs of extravasation was injected. Pullout forces showed significant differences (p < 0.001) between the augmented and non-augmented pedicle screws for bone densities below 0.8 g/cm2 (661.9 N ± 439) and over 0.8 g/cm2 (744.9 N ± 415). Pullout-forces were significantly increased in osteoporotic as well as in non-osteoporotic vertebral bodies without a significant difference between these groups using this standardized, simple procedure with increased control and less complications like extravasation.

Echocardiographic demonstration of intracardiac glue after endoscopic obturation of gastroesophageal varices.

PubMed

Gallet, B; Zemour, G; Saudemont, J P; Renard, P; Hillion, M L; Hiltgen, M

1995-01-01

Systemic embolism is an unusual complication of endoscopic obturation of gastroesophageal varices with glue. This report describes a case of cerebral embolism after this procedure. Intracardiac glue within the left atrium was demonstrated by echocardiography. Cardiac fluoroscopy demonstrated an abnormal vessel connecting periesophageal veins with the right upper pulmonary vein. Cardiac surgery was performed. Intracardiac glue was removed and the entering orifice of the abnormal vessel in the right upper pulmonary vein was sutured. To our knowledge, this is the first reported case of intracardiac glue after variceal obturation. Echocardiography is useful in the diagnosis of this rare complication.

Applications for a hybrid operating room in thoracic surgery: from multidisciplinary procedures to ­­image-guided video-assisted thoracoscopic surgery

PubMed Central

Terra, Ricardo Mingarini; Andrade, Juliano Ribeiro; Mariani, Alessandro Wasum; Garcia, Rodrigo Gobbo; Succi, Jose Ernesto; Soares, Andrey; Zimmer, Paulo Marcelo

2016-01-01

ABSTRACT The concept of a hybrid operating room represents the union of a high-complexity surgical apparatus with state-of-the-art radiological tools (ultrasound, CT, fluoroscopy, or magnetic resonance imaging), in order to perform highly effective, minimally invasive procedures. Although the use of a hybrid operating room is well established in specialties such as neurosurgery and cardiovascular surgery, it has rarely been explored in thoracic surgery. Our objective was to discuss the possible applications of this technology in thoracic surgery, through the reporting of three cases. PMID:27812640

Successful treatment of direct carotid-cavernous fistula in a patient with Ehlers-Danlos syndrome type IV without arterial puncture: the transvenous triple-overlay embolization (TAILOREd) technique.

PubMed

Huynh, Thien J; Morton, Ryan P; Levitt, Michael R; Ghodke, Basavaraj V; Wink, Onno; Hallam, Danial K

2017-08-18

We report successful transvenous treatment of direct carotid-cavernous fistula in a patient with Ehlers-Danlos syndrome type IV using a novel triple-overlay embolization (TAILOREd) technique without the need for arterial puncture, which is known to be highly risky in this patient group. The TAILOREd technique allowed for successful treatment using preoperative MR angiography as a three-dimensional overlay roadmap combined with cone beam CT and live fluoroscopy, precluding the need for an arterial puncture. 2017 BMJ Publishing Group Ltd.

Cine CT technique for dynamic airway studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ell, S.R.; Jolles, H.; Keyes, W.D.

1985-07-01

The advent of cine CT scanning with its 50-msec data acquisition time promises a much wider range of dynamic CT studies. The authors describe a method for dynamic evaluation of the extrathoracic airway, which they believe has considerable potential application in nonfixed upper-airway disease, such as sleep apnea and stridor of unknown cause. Conventional CT is limited in such studies by long data acquisition time and can be used to study only prolonged maneuvers such as phonation. Fluoroscopy and digital subtraction studies are limited by relatively high radiation dose and inability to image all wall motions simultaneously.

Optical Coherence Tomography and Stent Boost Imaging Guided Bioresorbable Vascular Scaffold Overlapping for Coronary Chronic Total Occlusion Lesion

PubMed Central

Li, Hu; Choi, Cheol Ung; Oh, Dong Joo

2017-01-01

We report herein the optical coherence tomography (OCT) and stent boost imaging guided bioresorbable vascular scaffold (BVS) implantation for right coronary artery (RCA) chronic total occlusion (CTO) lesion. The gold standard for evaluating BVS expansion after percutaneous coronary intervention is OCT. However, stent boost imaging is a new technique that improves fluoroscopy-based assessments of stent overlapping, and the present case shows clinical usefulness of OCT and stent boost imaging guided ‘overlapping’ BVS implantation via antegrade approach for a typical RCA CTO lesion. PMID:28792157

Image-guided interventional procedures in the dog and cat.

PubMed

Vignoli, Massimo; Saunders, Jimmy H

2011-03-01

Medical imaging is essential for the diagnostic workup of many soft tissue and bone lesions in dogs and cats, but imaging modalities do not always allow the clinician to differentiate inflammatory or infectious conditions from neoplastic disorders. This review describes interventional procedures in dogs and cats for collection of samples for cytological or histopathological examinations under imaging guidance. It describes the indications and procedures for imaging-guided sampling, including ultrasound (US), computed tomography (CT), magnetic resonance imaging and fluoroscopy. US and CT are currently the modalities of choice in interventional imaging. Copyright © 2009 Elsevier Ltd. All rights reserved.

ICRP publication 121: radiological protection in paediatric diagnostic and interventional radiology.

PubMed

Khong, P-L; Ringertz, H; Donoghue, V; Frush, D; Rehani, M; Appelgate, K; Sanchez, R

2013-04-01

Paediatric patients have a higher average risk of developing cancer compared with adults receiving the same dose. The longer life expectancy in children allows more time for any harmful effects of radiation to manifest, and developing organs and tissues are more sensitive to the effects of radiation. This publication aims to provide guiding principles of radiological protection for referring clinicians and clinical staff performing diagnostic imaging and interventional procedures for paediatric patients. It begins with a brief description of the basic concepts of radiological protection, followed by the general aspects of radiological protection, including principles of justification and optimisation. Guidelines and suggestions for radiological protection in specific modalities - radiography and fluoroscopy, interventional radiology, and computed tomography - are subsequently covered in depth. The report concludes with a summary and recommendations. The importance of rigorous justification of radiological procedures is emphasised for every procedure involving ionising radiation, and the use of imaging modalities that are non-ionising should always be considered. The basic aim of optimisation of radiological protection is to adjust imaging parameters and institute protective measures such that the required image is obtained with the lowest possible dose of radiation, and that net benefit is maximised to maintain sufficient quality for diagnostic interpretation. Special consideration should be given to the availability of dose reduction measures when purchasing new imaging equipment for paediatric use. One of the unique aspects of paediatric imaging is with regards to the wide range in patient size (and weight), therefore requiring special attention to optimisation and modification of equipment, technique, and imaging parameters. Examples of good radiographic and fluoroscopic technique include attention to patient positioning, field size and adequate collimation, use of protective shielding, optimisation of exposure factors, use of pulsed fluoroscopy, limiting fluoroscopy time, etc. Major paediatric interventional procedures should be performed by experienced paediatric interventional operators, and a second, specific level of training in radiological protection is desirable (in some countries, this is mandatory). For computed tomography, dose reduction should be optimised by the adjustment of scan parameters (such as mA, kVp, and pitch) according to patient weight or age, region scanned, and study indication (e.g. images with greater noise should be accepted if they are of sufficient diagnostic quality). Other strategies include restricting multiphase examination protocols, avoiding overlapping of scan regions, and only scanning the area in question. Up-to-date dose reduction technology such as tube current modulation, organ-based dose modulation, auto kV technology, and iterative reconstruction should be utilised when appropriate. It is anticipated that this publication will assist institutions in encouraging the standardisation of procedures, and that it may help increase awareness and ultimately improve practices for the benefit of patients. Copyright © 2012. Published by Elsevier Ltd.

Monte Carlo simulation of inverse geometry x-ray fluoroscopy using a modified MC-GPU framework

PubMed Central

Dunkerley, David A. P.; Tomkowiak, Michael T.; Slagowski, Jordan M.; McCabe, Bradley P.; Funk, Tobias; Speidel, Michael A.

2015-01-01

Scanning-Beam Digital X-ray (SBDX) is a technology for low-dose fluoroscopy that employs inverse geometry x-ray beam scanning. To assist with rapid modeling of inverse geometry x-ray systems, we have developed a Monte Carlo (MC) simulation tool based on the MC-GPU framework. MC-GPU version 1.3 was modified to implement a 2D array of focal spot positions on a plane, with individually adjustable x-ray outputs, each producing a narrow x-ray beam directed toward a stationary photon-counting detector array. Geometric accuracy and blurring behavior in tomosynthesis reconstructions were evaluated from simulated images of a 3D arrangement of spheres. The artifact spread function from simulation agreed with experiment to within 1.6% (rRMSD). Detected x-ray scatter fraction was simulated for two SBDX detector geometries and compared to experiments. For the current SBDX prototype (10.6 cm wide by 5.3 cm tall detector), x-ray scatter fraction measured 2.8–6.4% (18.6–31.5 cm acrylic, 100 kV), versus 2.1–4.5% in MC simulation. Experimental trends in scatter versus detector size and phantom thickness were observed in simulation. For dose evaluation, an anthropomorphic phantom was imaged using regular and regional adaptive exposure (RAE) scanning. The reduction in kerma-area-product resulting from RAE scanning was 45% in radiochromic film measurements, versus 46% in simulation. The integral kerma calculated from TLD measurement points within the phantom was 57% lower when using RAE, versus 61% lower in simulation. This MC tool may be used to estimate tomographic blur, detected scatter, and dose distributions when developing inverse geometry x-ray systems. PMID:26113765

Combination of CT scanning and fluoroscopy imaging on a flat-panel CT scanner

NASA Astrophysics Data System (ADS)

Grasruck, M.; Gupta, R.; Reichardt, B.; Suess, Ch.; Schmidt, B.; Stierstorfer, K.; Popescu, S.; Brady, T.; Flohr, T.

2006-03-01

We developed and evaluated a prototype flat-panel detector based Volume CT (fpVCT) scanner. The fpVCT scanner consists of a Varian 4030CB a-Si flat-panel detector mounted in a multi slice CT-gantry (Siemens Medical Solutions). It provides a 25 cm field of view with 18 cm z-coverage at the isocenter. In addition to the standard tomographic scanning, fpVCT allows two new scan modes: (1) fluoroscopic imaging from any arbitrary rotation angle, and (2) continuous, time-resolved tomographic scanning of a dynamically changing viewing volume. Fluoroscopic imaging is feasible by modifying the standard CT gantry so that the imaging chain can be oriented along any user-selected rotation angle. Scanning with a stationary gantry, after it has been oriented, is equivalent to a conventional fluoroscopic examination. This scan mode enables combined use of high-resolution tomography and real-time fluoroscopy with a clinically usable field of view in the z direction. The second scan mode allows continuous observation of a timeevolving process such as perfusion. The gantry can be continuously rotated for up to 80 sec, with the rotation time ranging from 3 to 20 sec, to gather projection images of a dynamic process. The projection data, that provides a temporal log of the viewing volume, is then converted into multiple image stacks that capture the temporal evolution of a dynamic process. Studies using phantoms, ex vivo specimens, and live animals have confirmed that these new scanning modes are clinically usable and offer a unique view of the anatomy and physiology that heretofore has not been feasible using static CT scanning. At the current level of image quality and temporal resolution, several clinical applications such a dynamic angiography, tumor enhancement pattern and vascularity studies, organ perfusion, and interventional applications are in reach.

Approach of forensic medicine to gossypiboma.

PubMed

Karakaya, M Arif; Koç, Okay; Ekiz, Feza; Ağaçhan, A Feran

2015-01-01

The aim of this study was to assess the risk factors and preventive measures for gossypibomas and their medico-legal implications in forensic medicine in the Turkish legal system. This study involved a retrospective analysis of the records of 39 patients with gossypiboma. Records were available from the Istanbul Forensic Medicine Institution and were surveyed for faulty treatment between 2008 and 2012. Parameters such as distribution of the cases according to specializations, elective and emergency procedures, surgical procedures, radio-opaque sponge and fluoroscopy availability, routine sponge and instrument counting, number of nurses for counting, and control of the operative field by a second surgeon were investigated. All cases were evaluated by the Istanbul Forensic Medicine Institute 3rd Expertise Committee. This committee comprised of specialists from the departments of forensic medicine, orthopedics and traumatology, general surgery, neurology, internal medicine, pediatrics, chest disease, and infectious diseases. All cases were considered as poor medical practice (malpractice) and surgeons were found to be responsible. In 16 of these 39 cases (41%) emergency procedures were performed. No unexpected event was reported in any procedure. In 16 cases (41%), sponge count was performed and was reported to be complete. Operation notes were available in 16 (41%) cases. Control of the operative field was performed by 1 surgeon, and sponge and instrument count was performed by 1 scrub nurse. Radio-opaque sponge and fluoroscopy were available in 9 (23%) centers in these cases. Gossypiboma can be prevented not only with surgeons' care but also with adequate support of medical device and material. However, it is considered as a poor medical practice. Presence of only 1 general surgeon in the expertise committee and ignorance of the working conditions by the surgeons should be questioned.