Clinical results of computerized tomography-based simulation with laser patient marking.

PubMed

Ragan, D P; Forman, J D; He, T; Mesina, C F

1996-02-01

Accuracy of a patient treatment portal marking device and computerized tomography (CT) simulation have been clinically tested. A CT-based simulator has been assembled based on a commercial CT scanner. This includes visualization software and a computer-controlled laser drawing device. This laser drawing device is used to transfer the setup, central axis, and/or radiation portals from the CT simulator to the patient for appropriate patient skin marking. A protocol for clinical testing is reported. Twenty-five prospectively, sequentially accessioned patients have been analyzed. The simulation process can be completed in an average time of 62 min. Under many cases, the treatment portals can be designed and the patient marked in one session. Mechanical accuracy of the system was found to be within +/- 1mm. The portal projection accuracy in clinical cases is observed to be better than +/- 1.2 mm. Operating costs are equivalent to the conventional simulation process it replaces. Computed tomography simulation is a clinical accurate substitute for conventional simulation when used with an appropriate patient marking system and digitally reconstructed radiographs. Personnel time spent in CT simulation is equivalent to time in conventional simulation.

Fracture healing using degradable magnesium fixation plates and screws.

PubMed

Chaya, Amy; Yoshizawa, Sayuri; Verdelis, Kostas; Noorani, Sabrina; Costello, Bernard J; Sfeir, Charles

2015-02-01

Internal bone fixation devices made with permanent metals are associated with numerous long-term complications and may require removal. We hypothesized that fixation devices made with degradable magnesium alloys could provide an ideal combination of strength and degradation, facilitating fracture fixation and healing while eliminating the need for implant removal surgery. Fixation plates and screws were machined from 99.9% pure magnesium and compared with titanium devices in a rabbit ulnar fracture model. Magnesium device degradation and the effect on fracture healing and bone formation were assessed after 4 weeks. Fracture healing with magnesium device fixation was compared with that of titanium devices using qualitative histologic analysis and quantitative histomorphometry. Micro-computed tomography showed device degradation after 4 weeks in vivo. In addition, 2-dimensional micro-computed tomography slices and histologic staining showed that magnesium degradation did not inhibit fracture healing or bone formation. Histomorphology showed no difference in bone-bridging fractures fixed with magnesium and titanium devices. Interestingly, abundant new bone was formed around magnesium devices, suggesting a connection between magnesium degradation and bone formation. Our results show potential for magnesium fixation devices in a loaded fracture environment. Furthermore, these results suggest that magnesium fixation devices may enhance fracture healing by encouraging localized new bone formation. Copyright © 2015 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Validation of a computational knee joint model using an alignment method for the knee laxity test and computed tomography.

PubMed

Kang, Kyoung-Tak; Kim, Sung-Hwan; Son, Juhyun; Lee, Young Han; Koh, Yong-Gon

2017-01-01

Computational models have been identified as efficient techniques in the clinical decision-making process. However, computational model was validated using published data in most previous studies, and the kinematic validation of such models still remains a challenge. Recently, studies using medical imaging have provided a more accurate visualization of knee joint kinematics. The purpose of the present study was to perform kinematic validation for the subject-specific computational knee joint model by comparison with subject's medical imaging under identical laxity condition. The laxity test was applied to the anterior-posterior drawer under 90° flexion and the varus-valgus under 20° flexion with a series of stress radiographs, a Telos device, and computed tomography. The loading condition in the computational subject-specific knee joint model was identical to the laxity test condition in the medical image. Our computational model showed knee laxity kinematic trends that were consistent with the computed tomography images, except for negligible differences because of the indirect application of the subject's in vivo material properties. Medical imaging based on computed tomography with the laxity test allowed us to measure not only the precise translation but also the rotation of the knee joint. This methodology will be beneficial in the validation of laxity tests for subject- or patient-specific computational models.

Surface radiation dose comparison of a dedicated extremity cone beam computed tomography (CBCT) device and a multidetector computed tomography (MDCT) machine in pediatric ankle and wrist phantoms

PubMed Central

Nagy, Eszter; Apfaltrer, Georg; Riccabona, Michael; Singer, Georg; Stücklschweiger, Georg; Guss, Helmuth; Sorantin, Erich

2017-01-01

Objectives To evaluate and compare surface doses of a cone beam computed tomography (CBCT) and a multidetector computed tomography (MDCT) device in pediatric ankle and wrist phantoms. Methods Thermoluminescent dosimeters (TLD) were used to measure and compare surface doses between CBCT and MDCT in a left ankle and a right wrist pediatric phantom. In both modalities adapted pediatric dose protocols were utilized to achieve realistic imaging conditions. All measurements were repeated three times to prove test-retest reliability. Additionally, objective and subjective image quality parameters were assessed. Results Average surface doses were 3.8 ±2.1 mGy for the ankle, and 2.2 ±1.3 mGy for the wrist in CBCT. The corresponding surface doses in optimized MDCT were 4.5 ±1.3 mGy for the ankle, and 3.4 ±0.7 mGy for the wrist. Overall, mean surface dose was significantly lower in CBCT (3.0 ±1.9 mGy vs. 3.9 ±1.2 mGy, p<0.001). Subjectively rated general image quality was not significantly different between the study protocols (p = 0.421), whereas objectively measured image quality parameters were in favor of CBCT (p<0.001). Conclusions Adapted extremity CBCT imaging protocols have the potential to fall below optimized pediatric ankle and wrist MDCT doses at comparable image qualities. These possible dose savings warrant further development and research in pediatric extremity CBCT applications. PMID:28570626

Analysis of intensity variability in multislice and cone beam computed tomography.

PubMed

Nackaerts, Olivia; Maes, Frederik; Yan, Hua; Couto Souza, Paulo; Pauwels, Ruben; Jacobs, Reinhilde

2011-08-01

The aim of this study was to evaluate the variability of intensity values in cone beam computed tomography (CBCT) imaging compared with multislice computed tomography Hounsfield units (MSCT HU) in order to assess the reliability of density assessments using CBCT images. A quality control phantom was scanned with an MSCT scanner and five CBCT scanners. In one CBCT scanner, the phantom was scanned repeatedly in the same and in different positions. Images were analyzed using registration to a mathematical model. MSCT images were used as a reference. Density profiles of MSCT showed stable HU values, whereas in CBCT imaging the intensity values were variable over the profile. Repositioning of the phantom resulted in large fluctuations in intensity values. The use of intensity values in CBCT images is not reliable, because the values are influenced by device, imaging parameters and positioning. © 2011 John Wiley & Sons A/S.

Using quantum process tomography to characterize decoherence in an analog electronic device

NASA Astrophysics Data System (ADS)

Ostrove, Corey; La Cour, Brian; Lanham, Andrew; Ott, Granville

The mathematical structure of a universal gate-based quantum computer can be emulated faithfully on a classical electronic device using analog signals to represent a multi-qubit state. We describe a prototype device capable of performing a programmable sequence of single-qubit and controlled two-qubit gate operations on a pair of voltage signals representing the real and imaginary parts of a two-qubit quantum state. Analog filters and true-RMS voltage measurements are used to perform unitary and measurement gate operations. We characterize the degradation of the represented quantum state with successive gate operations by formally performing quantum process tomography to estimate the equivalent decoherence channel. Experimental measurements indicate that the performance of the device may be accurately modeled as an equivalent quantum operation closely resembling a depolarizing channel with a fidelity of over 99%. This work was supported by the Office of Naval Research under Grant No. N00014-14-1-0323.

Comparison of Diagnostic Accuracy of Radiation Dose-Equivalent Radiography, Multidetector Computed Tomography and Cone Beam Computed Tomography for Fractures of Adult Cadaveric Wrists

PubMed Central

Neubauer, Jakob; Benndorf, Matthias; Reidelbach, Carolin; Krauß, Tobias; Lampert, Florian; Zajonc, Horst; Kotter, Elmar; Langer, Mathias; Fiebich, Martin; Goerke, Sebastian M.

2016-01-01

Purpose To compare the diagnostic accuracy of radiography, to radiography equivalent dose multidetector computed tomography (RED-MDCT) and to radiography equivalent dose cone beam computed tomography (RED-CBCT) for wrist fractures. Methods As study subjects we obtained 10 cadaveric human hands from body donors. Distal radius, distal ulna and carpal bones (n = 100) were artificially fractured in random order in a controlled experimental setting. We performed radiation dose equivalent radiography (settings as in standard clinical care), RED-MDCT in a 320 row MDCT with single shot mode and RED-CBCT in a device dedicated to musculoskeletal imaging. Three raters independently evaluated the resulting images for fractures and the level of confidence for each finding. Gold standard was evaluated by consensus reading of a high-dose MDCT. Results Pooled sensitivity was higher in RED-MDCT with 0.89 and RED-MDCT with 0.81 compared to radiography with 0.54 (P = < .004). No significant differences were detected concerning the modalities’ specificities (with values between P = .98). Raters' confidence was higher in RED-MDCT and RED-CBCT compared to radiography (P < .001). Conclusion The diagnostic accuracy of RED-MDCT and RED-CBCT for wrist fractures proved to be similar and in some parts even higher compared to radiography. Readers are more confident in their reporting with the cross sectional modalities. Dose equivalent cross sectional computed tomography of the wrist could replace plain radiography for fracture diagnosis in the long run. PMID:27788215

Computed tomography image using sub-terahertz waves generated from a high-T{sub c} superconducting intrinsic Josephson junction oscillator

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

Kashiwagi, T., E-mail: kashiwagi@ims.tsukuba.ac.jp; Minami, H.; Kadowaki, K.

2014-02-24

A computed tomography (CT) imaging system using monochromatic sub-terahertz coherent electromagnetic waves generated from a device constructed from the intrinsic Josephson junctions in a single crystalline mesa structure of the high-T{sub c} superconductor Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+δ} was developed and tested on three samples: Standing metallic rods supported by styrofoam, a dried plant (heart pea) containing seeds, and a plastic doll inside an egg shell. The images obtained strongly suggest that this CT imaging system may be useful for a variety of practical applications.

Three-dimensional photoacoustic tomography based on graphics-processing-unit-accelerated finite element method.

PubMed

Peng, Kuan; He, Ling; Zhu, Ziqiang; Tang, Jingtian; Xiao, Jiaying

2013-12-01

Compared with commonly used analytical reconstruction methods, the frequency-domain finite element method (FEM) based approach has proven to be an accurate and flexible algorithm for photoacoustic tomography. However, the FEM-based algorithm is computationally demanding, especially for three-dimensional cases. To enhance the algorithm's efficiency, in this work a parallel computational strategy is implemented in the framework of the FEM-based reconstruction algorithm using a graphic-processing-unit parallel frame named the "compute unified device architecture." A series of simulation experiments is carried out to test the accuracy and accelerating effect of the improved method. The results obtained indicate that the parallel calculation does not change the accuracy of the reconstruction algorithm, while its computational cost is significantly reduced by a factor of 38.9 with a GTX 580 graphics card using the improved method.

Opportunities for Fluorochlorozirconate and Other Glass-Ceramic Detectors in Medical Imaging Devices

PubMed Central

Johnson, Jacqueline A.; Leonard, Russell L.; Lubinsky, AR; Schweizer, Stefan

2017-01-01

This article gives an overview of fluorochlorozirconate glass-ceramic scintillators and storage phosphor materials: how they are synthesized, what their properties are, and how they can be used in medical imaging. Such materials can enhance imaging in x-ray radiography, especially mammography and dental imaging, computed tomography, and positron emission tomography. Although focusing on fluorochlorozirconate materials, the reader will find the discussion is relevant to other luminescent glass and glass-ceramic systems. PMID:28890955

General rigid motion correction for computed tomography imaging based on locally linear embedding

NASA Astrophysics Data System (ADS)

Chen, Mianyi; He, Peng; Feng, Peng; Liu, Baodong; Yang, Qingsong; Wei, Biao; Wang, Ge

2018-02-01

The patient motion can damage the quality of computed tomography images, which are typically acquired in cone-beam geometry. The rigid patient motion is characterized by six geometric parameters and are more challenging to correct than in fan-beam geometry. We extend our previous rigid patient motion correction method based on the principle of locally linear embedding (LLE) from fan-beam to cone-beam geometry and accelerate the computational procedure with the graphics processing unit (GPU)-based all scale tomographic reconstruction Antwerp toolbox. The major merit of our method is that we need neither fiducial markers nor motion-tracking devices. The numerical and experimental studies show that the LLE-based patient motion correction is capable of calibrating the six parameters of the patient motion simultaneously, reducing patient motion artifacts significantly.

Computed tomography of a medium size Roman bronze statue of Cupid

NASA Astrophysics Data System (ADS)

Bettuzzi, M.; Casali, F.; Morigi, M. P.; Brancaccio, R.; Carson, D.; Chiari, G.; Maish, J.

2015-03-01

Diagnostics based on X-ray computed tomography (CT) are becoming increasingly important, not only in the medical field but in industry and cultural heritage. CT devices typical for medical applications, however, can seldom be used on art objects because both they are not easily transportable and they often present high X-ray absorption. It is therefore necessary to make use of portable instrumentation and/or to develop tomographic systems optimized to the characteristics of the objects under examination. This work describes the computed tomography of a first century A.D. Roman bronze statue of Cupid (96.AB.53) in the collection of the J. Paul Getty Museum, within the collaborative framework between the Getty Conservation Institute and the Department of Physics and Astronomy (DIFA) of the University of Bologna (Italy). The tomography performed at the Getty facilities employed a 450 kV X-ray tube and a detection system developed at DIFA. The study highlighted the casting and construction techniques used by Roman foundry workers and provided information on the status of conservation of the statue. A 3D virtual reconstruction allowed the user to define different cross-sections enabling the study of the internal features.

Experimental study of heavy-ion computed tomography using a scintillation screen and an electron-multiplying charged coupled device camera for human head imaging

NASA Astrophysics Data System (ADS)

Muraishi, Hiroshi; Hara, Hidetake; Abe, Shinji; Yokose, Mamoru; Watanabe, Takara; Takeda, Tohoru; Koba, Yusuke; Fukuda, Shigekazu

2016-03-01

We have developed a heavy-ion computed tomography (IonCT) system using a scintillation screen and an electron-multiplying charged coupled device (EMCCD) camera that can measure a large object such as a human head. In this study, objective with the development of the system was to investigate the possibility of applying this system to heavy-ion treatment planning from the point of view of spatial resolution in a reconstructed image. Experiments were carried out on a rotation phantom using 12C accelerated up to 430 MeV/u by the Heavy-Ion Medical Accelerator in Chiba (HIMAC) at the National Institute of Radiological Sciences (NIRS). We demonstrated that the reconstructed image of an object with a water equivalent thickness (WET) of approximately 18 cm was successfully achieved with the spatial resolution of 1 mm, which would make this IonCT system worth applying to the heavy-ion treatment planning for head and neck cancers.

Digital 3D Microstructure Analysis of Concrete using X-Ray Micro Computed Tomography SkyScan 1173: A Preliminary Study

NASA Astrophysics Data System (ADS)

Latief, F. D. E.; Mohammad, I. H.; Rarasati, A. D.

2017-11-01

Digital imaging of a concrete sample using high resolution tomographic imaging by means of X-Ray Micro Computed Tomography (μ-CT) has been conducted to assess the characteristic of the sample’s structure. A standard procedure of image acquisition, reconstruction, image processing of the method using a particular scanning device i.e., the Bruker SkyScan 1173 High Energy Micro-CT are elaborated. A qualitative and a quantitative analysis were briefly performed on the sample to deliver some basic ideas of the capability of the system and the bundled software package. Calculation of total VOI volume, object volume, percent of object volume, total VOI surface, object surface, object surface/volume ratio, object surface density, structure thickness, structure separation, total porosity were conducted and analysed. This paper should serve as a brief description of how the device can produce the preferred image quality as well as the ability of the bundled software packages to help in performing qualitative and quantitative analysis.

Uses of megavoltage digital tomosynthesis in radiotherapy

NASA Astrophysics Data System (ADS)

Sarkar, Vikren

With the advent of intensity modulated radiotherapy, radiation treatment plans are becoming more conformal to the tumor with the decreasing margins. It is therefore of prime importance that the patient be positioned correctly prior to treatment. Therefore, image guided treatment is necessary for intensity modulated radiotherapy plans to be implemented successfully. Current advanced imaging devices require costly hardware and software upgrade, and radiation imaging solutions, such as cone beam computed tomography, may introduce extra radiation dose to the patient in order to acquire better quality images. Thus, there is a need to extend current existing imaging device ability and functions while reducing cost and radiation dose. Existing electronic portal imaging devices can be used to generate computed tomography-like tomograms through projection images acquired over a small angle using the technique of cone-beam digital tomosynthesis. Since it uses a fraction of the images required for computed tomography reconstruction, use of this technique correspondingly delivers only a fraction of the imaging dose to the patient. Furthermore, cone-beam digital tomosynthesis can be offered as a software-only solution as long as a portal imaging device is available. In this study, the feasibility of performing digital tomosynthesis using individually-acquired megavoltage images from a charge coupled device-based electronic portal imaging device was investigated. Three digital tomosynthesis reconstruction algorithms, the shift-and-add, filtered back-projection, and simultaneous algebraic reconstruction technique, were compared considering the final image quality and radiation dose during imaging. A software platform, DART, was created using a combination of the Matlab and C++ languages. The platform allows for the registration of a reference Cone Beam Digital Tomosynthesis (CBDT) image against a daily acquired set to determine how to shift the patient prior to treatment. Finally, the software was extended to investigate if the digital tomosynthesis dataset could be used in an adaptive radiotherapy regimen through the use of the Pinnacle treatment planning software to recalculate dose delivered. The feasibility study showed that the megavoltage CBDT visually agreed with corresponding megavoltage computed tomography images. The comparative study showed that the best compromise between imaging quality and imaging dose is obtained when 11 projection images, acquired over an imaging angle of 40°, are used with the filtered back-projection algorithm. DART was successfully used to register reference and daily image sets to within 1 mm in-plane and 2.5 mm out of plane. The DART platform was also effectively used to generate updated files that the Pinnacle treatment planning system used to calculate updated dose in a rigidly shifted patient. These doses were then used to calculate a cumulative dose distribution that could be used by a physician as reference to decide when the treatment plan should be updated. In conclusion, this study showed that a software solution is possible to extend existing electronic portal imaging devices to function as cone-beam digital tomosynthesis devices and achieve daily requirement for image guided intensity modulated radiotherapy treatments. The DART platform also has the potential to be used as a part of adaptive radiotherapy solution.

Molecular Imaging in the College of Optical Sciences – An Overview of Two Decades of Instrumentation Development

PubMed Central

Furenlid, Lars R.; Barrett, Harrison H.; Barber, H. Bradford; Clarkson, Eric W.; Kupinski, Matthew A.; Liu, Zhonglin; Stevenson, Gail D.; Woolfenden, James M.

2015-01-01

During the past two decades, researchers at the University of Arizona’s Center for Gamma-Ray Imaging (CGRI) have explored a variety of approaches to gamma-ray detection, including scintillation cameras, solid-state detectors, and hybrids such as the intensified Quantum Imaging Device (iQID) configuration where a scintillator is followed by optical gain and a fast CCD or CMOS camera. We have combined these detectors with a variety of collimation schemes, including single and multiple pinholes, parallel-hole collimators, synthetic apertures, and anamorphic crossed slits, to build a large number of preclinical molecular-imaging systems that perform Single-Photon Emission Computed Tomography (SPECT), Positron Emission Tomography (PET), and X-Ray Computed Tomography (CT). In this paper, we discuss the themes and methods we have developed over the years to record and fully use the information content carried by every detected gamma-ray photon. PMID:26236069

Development of a measurement system for the mechanical load of functional appliances.

PubMed

Shimazaki, Aya; Kimura, Hitoshi; Inou, Norio; Maki, Koutaro

2017-10-03

Devices called functional appliances are commonly used in orthodontics for treating maxillary protrusion. These devices mechanically force the mandible forward to apply traction force to the mandibular condyle. This promotes cartilaginous growth in the small mandible. However, no studies have clarified how much traction force is applied to the mandibular condyle. Moreover, it remains unknown as to how anatomical characteristics affect this traction force. Therefore, in this study, we developed a device for measuring the amount of force generated while individual patients wore functional appliances, and we investigated the relationship between forces with structures surrounding the mandibular condyle. We compared traction force values with cone-beam computed tomography image data in eight subjects. The functional appliance resulted in a traction force of 339-1477gf/mm, with a mean value of 196.5gf/mm for the elastic modulus of the mandible. A comparison with cone-beam computed tomography image data suggested that the mandibular traction force was affected by the mandibular condyle and shape of the articular eminence. This method can contribute to discovering efficient treatment techniques more suited to individual patients. Copyright © 2017 Elsevier Ltd. All rights reserved.

Linear Optimization and Image Reconstruction

DTIC Science & Technology

1994-06-01

final example is again a novel one. We formulate the problem of computer assisted tomographic ( CAT ) image reconstruction as a linear optimization...possibility that a patient, Fred, suffers from a brain tumor. Further, the physician opts to make use of the CAT (Computer Aided Tomography) scan device...and examine the inside of Fred’s head without exploratory surgery. The CAT scan machine works by projecting a finite number of X-rays of known

Fast simulation of Proton Induced X-Ray Emission Tomography using CUDA

NASA Astrophysics Data System (ADS)

Beasley, D. G.; Marques, A. C.; Alves, L. C.; da Silva, R. C.

2013-07-01

A new 3D Proton Induced X-Ray Emission Tomography (PIXE-T) and Scanning Transmission Ion Microscopy Tomography (STIM-T) simulation software has been developed in Java and uses NVIDIA™ Common Unified Device Architecture (CUDA) to calculate the X-ray attenuation for large detector areas. A challenge with PIXE-T is to get sufficient counts while retaining a small beam spot size. Therefore a high geometric efficiency is required. However, as the detector solid angle increases the calculations required for accurate reconstruction of the data increase substantially. To overcome this limitation, the CUDA parallel computing platform was used which enables general purpose programming of NVIDIA graphics processing units (GPUs) to perform computations traditionally handled by the central processing unit (CPU). For simulation performance evaluation, the results of a CPU- and a CUDA-based simulation of a phantom are presented. Furthermore, a comparison with the simulation code in the PIXE-Tomography reconstruction software DISRA (A. Sakellariou, D.N. Jamieson, G.J.F. Legge, 2001) is also shown. Compared to a CPU implementation, the CUDA based simulation is approximately 30× faster.

Computed tomography-assisted laparoscopic removal of intraabdominally migrated levonorgestrel-releasing intrauterine systems.

PubMed

Mahmoud, Mohamad S; Merhi, Zaher O

2010-04-01

To report three cases of migrated levonorgestrel intrauterine device (LNG-IUS) into the pelvic/abdominal cavity removed laparoscopically with the aid of preoperative computed tomography (CT) scan imaging. Three patients presenting with a missing LNG-IUS on examination and pelvic ultrasound are presented. A preoperative CT scan was performed, what helped in a successful removal of the LNG-IUS. The patients were discharged home the same day of the procedure. Our cases reinforce, besides the diagnosis of a migrated LNG-IUS by ultrasound, the fact that preoperative CT scan imaging assists in the diagnosis of the precise location of a migrated LNG-IUS into the pelvic/abdominal cavity and helps the physician in the prediction of the difficulty of the laparoscopic removal.

Development of seismic tomography software for hybrid supercomputers

NASA Astrophysics Data System (ADS)

Nikitin, Alexandr; Serdyukov, Alexandr; Duchkov, Anton

2015-04-01

Seismic tomography is a technique used for computing velocity model of geologic structure from first arrival travel times of seismic waves. The technique is used in processing of regional and global seismic data, in seismic exploration for prospecting and exploration of mineral and hydrocarbon deposits, and in seismic engineering for monitoring the condition of engineering structures and the surrounding host medium. As a consequence of development of seismic monitoring systems and increasing volume of seismic data, there is a growing need for new, more effective computational algorithms for use in seismic tomography applications with improved performance, accuracy and resolution. To achieve this goal, it is necessary to use modern high performance computing systems, such as supercomputers with hybrid architecture that use not only CPUs, but also accelerators and co-processors for computation. The goal of this research is the development of parallel seismic tomography algorithms and software package for such systems, to be used in processing of large volumes of seismic data (hundreds of gigabytes and more). These algorithms and software package will be optimized for the most common computing devices used in modern hybrid supercomputers, such as Intel Xeon CPUs, NVIDIA Tesla accelerators and Intel Xeon Phi co-processors. In this work, the following general scheme of seismic tomography is utilized. Using the eikonal equation solver, arrival times of seismic waves are computed based on assumed velocity model of geologic structure being analyzed. In order to solve the linearized inverse problem, tomographic matrix is computed that connects model adjustments with travel time residuals, and the resulting system of linear equations is regularized and solved to adjust the model. The effectiveness of parallel implementations of existing algorithms on target architectures is considered. During the first stage of this work, algorithms were developed for execution on supercomputers using multicore CPUs only, with preliminary performance tests showing good parallel efficiency on large numerical grids. Porting of the algorithms to hybrid supercomputers is currently ongoing.

Endobag separation - an ominous sign after endovascular aneurysm sealing with the Nellix device.

PubMed

Tasleem, Sadia; Badri, Hassan; Ranjeet, Narlawar; Antoniou, George A

2018-06-01

Our report aims to alert physicians performing endovascular aneurysm sealing with the Nellix endoprosthesis to the risk of rupture when endobag separation is noticed on computed tomography. Endobag separation when observed with acute presentation of abdominal pain is an indicator of imminent rupture and prompt interventional treatment should be undertaken.

Assessment of Safety and Interference Issues of Radio Frequency Identification Devices in 0.3 Tesla Magnetic Resonance Imaging and Computed Tomography

PubMed Central

Periyasamy, M.; Dhanasekaran, R.

2014-01-01

The objective of this study was to evaluate two issues regarding magnetic resonance imaging (MRI) including device functionality and image artifacts for the presence of radio frequency identification devices (RFID) in association with 0.3 Tesla at 12.7 MHz MRI and computed tomography (CT) scanning. Fifteen samples of RFID tags with two different sizes (wristband and ID card types) were tested. The tags were exposed to several MR-imaging conditions during MRI examination and X-rays of CT scan. Throughout the test, the tags were oriented in three different directions (axial, coronal, and sagittal) relative to MRI system in order to cover all possible situations with respect to the patient undergoing MRI and CT scanning, wearing a RFID tag on wrist. We observed that the tags did not sustain physical damage with their functionality remaining unaffected even after MRI and CT scanning, and there was no alternation in previously stored data as well. In addition, no evidence of either signal loss or artifact was seen in the acquired MR and CT images. Therefore, we can conclude that the use of this passive RFID tag is safe for a patient undergoing MRI at 0.3 T/12.7 MHz and CT Scanning. PMID:24701187

Development of Novel Treatment Plan Verification Techniques for Prostate Intensity Modulation Arc Therapy

DTIC Science & Technology

2010-03-01

is to develop a novel clinical useful delivered-dose verification protocol for modern prostate VMAT using Electronic Portal Imaging Device (EPID...technique. A number of important milestones have been accomplished, which include (i) calibrated CBCT HU vs. electron density curve; (ii...prostate  VMAT  using  Electronic   Portal  Imaging  Device  (EPID)  and  onboard Cone beam Computed Tomography (CBCT).  The specific aims of this project

Navigation in head and neck oncological surgery: an emerging concept.

PubMed

Gangloff, P; Mastronicola, R; Cortese, S; Phulpin, B; Sergeant, C; Guillemin, F; Eluecque, H; Perrot, C; Dolivet, G

2011-01-01

Navigation surgery, initially applied in rhinology, neurosurgery and orthopaedic cases, has been developed over the last twenty years. Surgery based on computed tomography data has become increasingly important in the head and neck region. The technique for hardware fusion between RMI and computed tomography is also becoming more useful. We use such device since 2006 in head and neck carcinologic situation. Navigation allows control of the resection in order to avoid and protect the precise anatomical structures (vessels and nerves). It also guides biopsy and radiofrequency. Therefore, quality of life is much more increased and morbidity is decreased for these patients who undergo major and mutilating head and neck surgery. Here we report the results of 33 navigation procedures performed for 31 patients in our institution.

The application of X-ray microtomography for the assessement of root resorption caused by the orthodontic treatment of premolars.

PubMed

Sawicka, Monika; Bedini, Rossella; Pecci, Raffaella; Pameijer, Cornelis Hans; Kmiec, Zbigniew

2012-01-01

The purpose of this study was to demonstrate potential application of micro-computed tomography in the morphometric analysis of the root resorption in extracted human first premolars subjected to the orthodontic force. In one patient treated in the orthodontic clinic two mandibular first premolars subjected to orthodontic force for 4 weeks and one control tooth were selected for micro-computed tomographic analysis. The hardware device used in this study was a desktop X-ray microfocus CT scanner (SkyScan 1072). The morphology of root's surfaces was assessed by TView and Computer Tomography Analyzer (CTAn) softwares (SkyScan, bvba) which allowed analysis of all microscans, identification of root resorption craters and measurement of their length, width and volume. Microscans showed in details the surface morphology of the investigated teeth. The analysis of microscans allowed to detect 3 root resorption cavities in each of the orthodontically moved tooth and only one resorption crater in the control tooth. The volumes of the resorption craters in orthodontically-treated teeth were much larger than in a control tooth. Micro-computed tomography is a reproducible technique for the three-dimensional non-invasive assessment of root's morphology ex vivo. TView and CTan softwares are useful in accurate morphometric measurements of root's resorption.

Noninvasive Assessment of Left Ventricular Assist Devices with Cardiovascular Computed Tomography and Impact on Management

PubMed Central

Raman, Subha V.; Sahu, Anurag; Merchant, Ali Z.; Louis, Louis B.; Firstenberg, Michael S.; Sun, Benjamin

2009-01-01

Background Left ventricular assist devices (LVADs) provide a bridge to recovery or heart transplantation, but require serial assessment. Echocardiographic approaches may be limited by device artifact and acoustic window. Cardiovascular computed tomography (CCT) provides noninvasive imaging of LVADs, yet no study has evaluated CCT’s impact on clinical care. We evaluated the diagnostic findings and clinical impact of CCT for noninvasive assessment of patients with LVADs. Methods CCT examinations performed between 2005 and 2008 in patients with LVADs were identified. Acquisitions were completed on the identical 64 detector-row scanner with intravenous contrast administration; electrocardiographic gating was used in patients with pulsatile devices, while peripheral pulse gating was used in patients with continuous-flow devices. Comparison was made between CCT results and 30-day outcomes, including echocardiographic and intraoperative findings. Results Thirty-two CCT examinations from 28 patients were reviewed. Indications included evaluation of low cardiac output symptoms, assessment of cannula position, low flow reading on the LVAD, and surgical planning. CCT identified critical findings in 6 patients including thrombosis and inlet cannula malposition, all confirmed intraoperatively; one case of intra-LVAD thrombus was missed by CCT. Using intraoperative findings as the gold standard, CCT’s sensitivity was 85% and specificity was 100%. Echocardiographic LVAD evaluation did not correlate with findings on CCT (kappa = −0.29, 95% CI −0.73−0.13). Conclusions This preliminary observational cohort study indicates that noninvasive imaging using CCT of LVADs is feasible and accurate. CCT warrants consideration in the initial evaluation of symptomatic patients with LVADs. PMID:19782594

Government health policy and the diffusion of new medical devices.

PubMed Central

Hillman, B J

1986-01-01

The combination of absent financial incentives, aspects of physicians' clinical training, and the uncertainty surrounding the appropriate application of expensive new medical devices have been the most significant factors in promoting their wasteful diffusion and use. This presentation summarizes the forces that have resulted in regulatory and reimbursement initiatives to make more efficient the acquisition and utilization of new medical devices. The case histories of computed tomography (CT) and magnetic resonance imaging (MRI) serve as a paradigm demonstrating why such initiatives have thus far proved ineffectual. More effective would be to abandon distinctions between inpatient and outpatient reimbursement for using new medical devices and to improve the relationship between reimbursement and technology assessment. PMID:3818311

Use of PET/CT scanning in cancer patients: technical and practical considerations

PubMed Central

2005-01-01

This overview of the oncologic applications of positron emission tomography (PET) focuses on the technical aspects and clinical applications of a newer technique: the combination of a PET scanner and a computed tomography (CT) scanner in a single (PET/CT) device. Examples illustrate how PET/CT contributes to patient care and improves upon the previous state-of-the-art method of comparing a PET scan with a separate CT scan. Finally, the author presents some of the results from studies of PET/CT imaging that are beginning to appear in the literature. PMID:16252023

Positron Emission Tomography - Computed Tomography (PET/CT)

MedlinePlus

... A-Z Positron Emission Tomography - Computed Tomography (PET/CT) Positron emission tomography (PET) uses small amounts of ... What is Positron Emission Tomography – Computed Tomography (PET/CT) Scanning? Positron emission tomography, also called PET imaging ...

Inpainting approaches to fill in detector gaps in phase contrast computed tomography

NASA Astrophysics Data System (ADS)

Brun, F.; Delogu, P.; Longo, R.; Dreossi, D.; Rigon, L.

2018-01-01

Photon counting semiconductor detectors in radiation imaging present attractive properties, such as high efficiency, low noise, and energy sensitivity. The very complex electronics limits the sensitive area of current devices to a few square cm. This disadvantage is often compensated by tiling a larger matrix with an adequate number of detector units but this usually results in non-negligible insensitive gaps between two adjacent modules. When considering the case of Computed Tomography (CT), these gaps lead to degraded reconstructed images with severe streak and ring artifacts. This work presents two digital image processing solutions to fill in these gaps when considering the specific case of synchrotron radiation x-ray parallel beam phase contrast CT. While not discussed with experimental data, other CT modalities, such as spectral, cone beam and other geometries might benefit from the presented approaches.

Numerical Analysis of Organ Doses Delivered During Computed Tomography Examinations Using Japanese Adult Phantoms with the WAZA-ARI Dosimetry System.

PubMed

Takahashi, Fumiaki; Sato, Kaoru; Endo, Akira; Ono, Koji; Ban, Nobuhiko; Hasegawa, Takayuki; Katsunuma, Yasushi; Yoshitake, Takayasu; Kai, Michiaki

2015-08-01

A dosimetry system for computed tomography (CT) examinations, named WAZA-ARI, is being developed to accurately assess radiation doses to patients in Japan. For dose calculations in WAZA-ARI, organ doses were numerically analyzed using average adult Japanese male (JM) and female (JF) phantoms with the Particle and Heavy Ion Transport code System (PHITS). Experimental studies clarified the photon energy distribution of emitted photons and dose profiles on the table for some multi-detector row CT (MDCT) devices. Numerical analyses using a source model in PHITS could specifically take into account emissions of x rays from the tube to the table with attenuation of photons through a beam-shaping filter for each MDCT device based on the experiment results. The source model was validated by measuring the CT dose index (CTDI). Numerical analyses with PHITS revealed a concordance of organ doses with body sizes of the JM and JF phantoms. The organ doses in the JM phantoms were compared with data obtained using previously developed systems. In addition, the dose calculations in WAZA-ARI were verified with previously reported results by realistic NUBAS phantoms and radiation dose measurement using a physical Japanese model (THRA1 phantom). The results imply that numerical analyses using the Japanese phantoms and specified source models can give reasonable estimates of dose for MDCT devices for typical Japanese adults.

Wireless Synchronization of a Multi-Pinhole Small Animal SPECT Collimation Device With a Clinical Scanner

NASA Astrophysics Data System (ADS)

DiFilippo, Frank P.; Patel, Sagar

2009-06-01

A multi-pinhole collimation device for small animal single photon emission computed tomography (SPECT) uses the gamma camera detectors of a standard clinical SPECT scanner. The collimator and animal bed move independently of the detectors, and therefore their motions must be synchronized. One approach is manual triggering of the SPECT acquisition simultaneously with a programmed motion sequence for the device. However, some data blurring and loss of image quality result, and true electronic synchronization is preferred. An off-the-shelf digital gyroscope with integrated Bluetooth interface provides a wireless solution to device synchronization. The sensor attaches to the SPECT gantry and reports its rotational speed to a notebook computer controlling the device. Software processes the rotation data in real-time, averaging the signal and issuing triggers while compensating for baseline drift. Motion commands are sent to the collimation device with minimal delay, within approximately 0.5 second of the start of SPECT gantry rotation. Test scans of a point source demonstrate an increase in true counts and a reduction in background counts compared to manual synchronization. The wireless rotation sensor provides robust synchronization of the collimation device with the clinical SPECT scanner and enhances image quality.

Relationship between the Self-Rating Anxiety Scale score and the success rate of 64-slice computed tomography coronary angiography.

PubMed

Li, Hui; Jin, Dan; Qiao, Fang; Chen, Jianchang; Gong, Jianping

Computed tomography coronary angiography, a key method for obtaining coronary artery images, is widely used to screen for coronary artery diseases due to its noninvasive nature. In China, 64-slice computed tomography systems are now the most common models. As factors that directly affect computed tomography performance, heart rate and rhythm control are regulated by the autonomic nervous system and are highly related to the emotional state of the patient. The aim of this prospective study is to use a pre-computed tomography scan Self-Rating Anxiety Scale assessment to analyze the effects of tension and anxiety on computed tomography coronary angiography success. Subjects aged 18-85 years who were planned to undergo computed tomography coronary angiography were enrolled; 1 to 2 h before the computed tomography scan, basic patient data (gender, age, heart rate at rest, and family history) and Self-Rating Anxiety Scale score were obtained. The same group of imaging department doctors, technicians, and nurses performed computed tomography coronary angiography for all the enrolled subjects and observed whether those subjects could finish the computed tomography coronary angiography scan and provide clear, diagnostically valuable images. Participants were divided into successful (obtained diagnostically useful coronary images) and unsuccessful groups. Basic data and Self-Rating Anxiety Scale scores were compared between the groups. The Self-Rating Anxiety Scale standard score of the successful group was lower than that of the unsuccessful group (P = 0.001). As the Self-Rating Anxiety Scale standard score rose, the success rate of computed tomography coronary angiography decreased. The Self-Rating Anxiety Scale score has a negative relationship with computed tomography coronary angiography success. Anxiety can be a disadvantage in computed tomography coronary angiography examination. The pre-computed tomography coronary angiography scan Self-Rating Anxiety Scale score may be a useful tool for assessing whether a computed tomography coronary angiography scan will be successful or not. © The Author(s) 2015.

Utility of hand-held devices in diagnosis and triage of cardiovascular emergencies. Observations during implementation of a PACS-based system in an acute aortic syndrome (AAS) network.

PubMed

Matar, Ralph; Renapurkar, Rahul; Obuchowski, Nancy; Menon, Venu; Piraino, David; Schoenhagen, Paul

2015-01-01

Prompt diagnosis and early referral to specialized centers is critical for patients presenting with cardiovascular emergencies, including acute aortic syndromes (AAS). Prior data has suggested that mobile access to imaging studies with hand-held devices can accelerate diagnosis and management. We conducted a study to determine the diagnostic accuracy of a hand-held device compared to conventional dedicated work-stations for diagnosing a spectrum of cardiovascular emergencies, predominantly acute aortic pathology. This study included 104 cases who underwent computed tomography (CT)-scan during "on-call'' hours between January, 2013 and August, 2014 for suspected AAS. Assessment was performed on a hand-held device independently by two readers using an iPhone5 connected via secure connection to web-based PACS servers. The subsequent interpretation from a dedicated workstation coupled with the diagnosis at the time of discharge was used as the reference standard for determining the presence or absence of an acute abnormality. Sensitivity and Specificity were calculated on a per patient basis. Readers' sensitivity and specificity using the hand-held device to diagnose acute chest pathology were calculated. Hand-held device evaluation was determined to have a sensitivity of 85.2% and a specificity of 98.6% by reader A and a sensitivity of 96.3% and specificity of 100% by reader B. Of 103 cases interpreted by both readers, the readers agreed about the diagnosis in 98 cases (95.1%). This study demonstrates that hand-held devices can be a potential useful tool to assist in diagnosis and triage of patients presenting with cardiovascular emergencies. Further studies are needed to assess the impact of screen size and resolution. Copyright © 2015 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.

Is it possible to reduce intra-hospital transport time for computed tomography evaluation in critically ill cases using the Easy Tube Arrange Device?

PubMed

Song, Kyung Hyeok; Cho, Sung Uk; Lee, Jin Woong; Cho, Yong Chul; Jeong, Won Joon; You, Yeon Ho; Ryu, Seung; Kim, Seung Whan; Yoo, In Sool; Joo, Ki Hyuk

2018-03-01

Patients are often transported within the hospital, especially in cases of critical illness for which computed tomography (CT) is performed. Since increased transport time increases the risks of complications, reducing transport time is important for patient safety. This study aimed to evaluate the ability of our newly invented device, the Easy Tube Arrange Device (ETAD), to reduce transport time for CT evaluation in cases of critical illness. This prospective randomized control study included 60 volunteers. Each participant arranged five or six intravenous fluid lines, monitoring lines (noninvasive blood pressure, electrocardiography, central venous pressure, arterial catheter), and therapeutic equipment (O2 supply device, Foley catheter) on a Resusci Anne mannequin. We measured transport time for the CT evaluation by using conventional and ETAD method. The median transport time for CT evaluation was 488.50 seconds (95% confidence interval [CI], 462.75 to 514.75) and, 503.50 seconds (95% CI, 489.50 to 526.75) with 5 and 6 fluid lines using the conventional method and 364.50 seconds (95% CI, 335.00 to 388.75), and 363.50 seconds (95% CI, 331.75 to 377.75) with ETAD (all P<0.001). The time differences were 131.50 (95% CI, 89.25 to 174.50) and 148.00 (95% CI, 116.00 to 177.75) (all P<0.001). The transport time for CT evaluation was reduced using the ETAD, which would be expected to reduce the complications that may occur during transport in cases of critical illness.

Computed Tomography (CT) - Spine

MedlinePlus

... Resources Professions Site Index A-Z Computed Tomography (CT) - Spine Computed tomography (CT) of the spine is ... of CT Scanning of the Spine? What is CT Scanning of the Spine? Computed tomography, more commonly ...

Differential diagnosis of endodontic-related inferior alveolar nerve paraesthesia with cone beam computed tomography: a case report.

PubMed

Gambarini, G; Plotino, G; Grande, N M; Testarelli, L; Prencipe, M; Messineo, D; Fratini, L; D'Ambrosio, F

2011-02-01

To discuss the use of cone-beam computed tomography (CBCT) in the differential diagnosis of a case of labiomandibular paraesthesia caused by extrusion of endodontic sealer into the mandibular canal. A 59-year-old woman suffering from a paraesthesia on the left posterior mandible and numbness on the left side of the lower lip was referred to an endodontic specialist 1 month after multiple root canal treatments. A panoramic radiograph revealed the presence of extruded root filling material beyond the apex of the mesial root of the mandibular left second molar and also beyond the apex of the first premolar. A cone beam computed tomography examination was undertaken, which confirmed the presence of radiopaque root canal filling material in the periapical area of the second molar, and revealed that the material was inside the mandibular canal. No extruded filling material was found inside the mental foramen beyond the apex of the first premolar tooth. Small field of view CBCT (where possible) can be considered an effective radiographic diagnostic device when endodontic-related inferior alveolar nerve or mental foramen paraesthesia are suspected. CBCT is able to provide detailed three-dimensional images of the tooth, the root canal system and the surrounding tissue. © 2010 International Endodontic Journal.

Physical analysis of breast cancer using dual-source computed tomography

NASA Astrophysics Data System (ADS)

Kim, H. J.; Lee, H. K.; Cho, J. H.

2014-12-01

This study was aimed to analyze various physical characteristics of breast cancer using dual-source computed tomography (CT). A phantom study and a clinical trial were performed in order and a 64-multidetector CT device was used for the examinations. In the phantom study, single-source (SS) CT was set up with a conventional scanning condition that is usually applied for breast CT examination and implementation was done at tube voltage of 120 kVp. Dual-source CT acquired images by irradiating X-ray sources with fast switching between two kilovoltage settings (80 and 140 kVp). After scanning, Hounsfield Unit (HU) values and radiation doses in a region of interest were measured and analyzed. In the clinical trial, the HU values were measured and analyzed after single-source computed tomography (SSCT) and dual-source CT in patients diagnosed with breast cancer. Also, the tumor size measured by dual-source CT was compared with the actual tumor size. The phantom study determined that the tumor region was especially measured by dual-source CT, while nylon fiber and specks region were especially measured by SSCT. The radiation dose was high with dual-source CT. The clinical trial showed a higher HU value of cancerous regions when scanned by dual-source CT compared with SSCT.

Diffuse optical tomography for breast cancer imaging guided by computed tomography: A feasibility study.

PubMed

Baikejiang, Reheman; Zhang, Wei; Li, Changqing

2017-01-01

Diffuse optical tomography (DOT) has attracted attentions in the last two decades due to its intrinsic sensitivity in imaging chromophores of tissues such as hemoglobin, water, and lipid. However, DOT has not been clinically accepted yet due to its low spatial resolution caused by strong optical scattering in tissues. Structural guidance provided by an anatomical imaging modality enhances the DOT imaging substantially. Here, we propose a computed tomography (CT) guided multispectral DOT imaging system for breast cancer imaging. To validate its feasibility, we have built a prototype DOT imaging system which consists of a laser at the wavelength of 650 nm and an electron multiplying charge coupled device (EMCCD) camera. We have validated the CT guided DOT reconstruction algorithms with numerical simulations and phantom experiments, in which different imaging setup parameters, such as projection number of measurements and width of measurement patch, have been investigated. Our results indicate that an air-cooling EMCCD camera is good enough for the transmission mode DOT imaging. We have also found that measurements at six angular projections are sufficient for DOT to reconstruct the optical targets with 2 and 4 times absorption contrast when the CT guidance is applied. Finally, we have described our future research plan on integration of a multispectral DOT imaging system into a breast CT scanner.

Recent Advances in Cardiac Computed Tomography: Dual Energy, Spectral and Molecular CT Imaging

PubMed Central

Danad, Ibrahim; Fayad, Zahi A.; Willemink, Martin J.; Min, James K.

2015-01-01

Computed tomography (CT) evolved into a powerful diagnostic tool and it is impossible to imagine current clinical practice without CT imaging. Due to its widespread availability, ease of clinical application, superb sensitivity for detection of CAD, and non-invasive nature, CT has become a valuable tool within the armamentarium of the cardiologist. In the last few years, numerous technological advances in CT have occurred—including dual energy CT (DECT), spectral CT and CT-based molecular imaging. By harnessing the advances in technology, cardiac CT has advanced beyond the mere evaluation of coronary stenosis to an imaging modality tool that permits accurate plaque characterization, assessment of myocardial perfusion and even probing of molecular processes that are involved in coronary atherosclerosis. Novel innovations in CT contrast agents and pre-clinical spectral CT devices have paved the way for CT-based molecular imaging. PMID:26068288

Cardiovascular Computed Tomography Phantom Fabrication and Characterization through the Tailored Properties of Polymeric Composites and Cellular Foams

NASA Astrophysics Data System (ADS)

Hoy, Carlton F. O.

The overall objective of this thesis was to control the fabrication technique and relevant material properties for phantom devices designated for computed tomography (CT) scanning. Fabrication techniques using polymeric composites and foams were detailed together with parametric studies outlining the fundamentals behind the changes in material properties which affect the characteristic CT number. The composites fabricated used polyvinylidene fluoride (PVDF), thermoplastic polyurethane (TPU) and polyethylene (PE) with hydroxylapatite (hA) as additive with different composites made by means of different weight percentages of additive. Polymeric foams were fabricated through a batch foaming technique with the heating time controlled to create different levels of foams. Finally, the effect of fabricated phantoms under varied scanning media was assessed to determine whether self-made phantoms can be scanned accurately under non-water or rigid environments allowing for the future development of complex shaped or fragile material types.

Neural-network quantum state tomography

NASA Astrophysics Data System (ADS)

Torlai, Giacomo; Mazzola, Guglielmo; Carrasquilla, Juan; Troyer, Matthias; Melko, Roger; Carleo, Giuseppe

2018-05-01

The experimental realization of increasingly complex synthetic quantum systems calls for the development of general theoretical methods to validate and fully exploit quantum resources. Quantum state tomography (QST) aims to reconstruct the full quantum state from simple measurements, and therefore provides a key tool to obtain reliable analytics1-3. However, exact brute-force approaches to QST place a high demand on computational resources, making them unfeasible for anything except small systems4,5. Here we show how machine learning techniques can be used to perform QST of highly entangled states with more than a hundred qubits, to a high degree of accuracy. We demonstrate that machine learning allows one to reconstruct traditionally challenging many-body quantities—such as the entanglement entropy—from simple, experimentally accessible measurements. This approach can benefit existing and future generations of devices ranging from quantum computers to ultracold-atom quantum simulators6-8.

Design and Construction of a Field Capable Snapshot Hyperspectral Imaging Spectrometer

NASA Technical Reports Server (NTRS)

Arik, Glenda H.

2005-01-01

The computed-tomography imaging spectrometer (CTIS) is a device which captures the spatial and spectral content of a rapidly evolving same in a single image frame. The most recent CTIS design is optically all reflective and uses as its dispersive device a stated the-art reflective computer generated hologram (CGH). This project focuses on the instrument's transition from laboratory to field. This design will enable the CTIS to withstand a harsh desert environment. The system is modeled in optical design software using a tolerance analysis. The tolerances guide the design of the athermal mount and component parts. The parts are assembled into a working mount shell where the performance of the mounts is tested for thermal integrity. An interferometric analysis of the reflective CGH is also performed.

Clinical value of whole body fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography in the detection of metastatic bladder cancer.

PubMed

Yang, Zhongyi; Pan, Lingling; Cheng, Jingyi; Hu, Silong; Xu, Junyan; Ye, Dingwei; Zhang, Yingjian

2012-07-01

To investigate the value of whole-body fluorine-18 2-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography for the detection of metastatic bladder cancer. From December 2006 to August 2010, 60 bladder cancer patients (median age 60.5 years old, range 32-96) underwent whole body positron emission tomography/computed tomography positron emission tomography/computed tomography. The diagnostic accuracy was assessed by performing both organ-based and patient-based analyses. Identified lesions were further studied by biopsy or clinically followed for at least 6 months. One hundred and thirty-four suspicious lesions were identified. Among them, 4 primary cancers (2 pancreatic cancers, 1 colonic and 1 nasopharyngeal cancer) were incidentally detected, and the patients could be treated on time. For the remaining 130 lesions, positron emission tomography/computed tomography detected 118 true positive lesions (sensitivity = 95.9%). On the patient-based analysis, the overall sensitivity and specificity resulted to be 87.1% and 89.7%, respectively. There was no difference of sensitivity and specificity in patients with or without adjuvant treatment in terms of detection of metastatic sites by positron emission tomography/computed tomography. Compared with conventional imaging modality, positron emission tomography/computed tomography correctly changed the management in 15 patients (25.0%). Positron emission tomography/computed tomography has excellent sensitivity and specificity in the detection of metastatic bladder cancer and it provides additional diagnostic information compared to standard imaging techniques. © 2012 The Japanese Urological Association.

A Guide to Computed Tomography System Specifications

DTIC Science & Technology

1990-08-01

particularly where anomalies are not known or expected, where nonimaging measurements of deviations from a norm defy experience or expectation, or...point. 2.9 Archival Requirements Archival requirements usually involve hardcopy, tape, and/or optical disk. These dictate a small subsystem choice, but...some kind of scintillating X-ray crystal, e.g., cadmium tungstate or bismuth germanate that is optically coupled to a photoconversion device like a

Practical human abdominal fat imaging utilizing electrical impedance tomography.

PubMed

Yamaguchi, T; Maki, K; Katashima, M

2010-07-01

The fundamental cause of metabolic syndrome is thought to be abdominal obesity. Accurate diagnosis of abdominal obesity can be done by an x-ray computed tomography (CT) scan. But CT is expensive, bulky and entails the risks involved with radiation. To overcome such disadvantages, we attempted to develop a measuring device that could apply electrical impedance tomography to abdominal fat imaging. The device has 32 electrodes that can be attached to a subject's abdomen by a pneumatic mechanism. That way, electrode position data can be acquired simultaneously. An applied alternating current of 1.0 mArms was used at a frequency of 500 kHz. Sensed voltage data were carefully filtered to remove noise and processed to satisfy the reciprocal theorem. The image reconstruction software was developed concurrently, applying standard finite element methods and the Marquardt method to solve the mathematical inverse problem. The results of preliminary experiments showed that abdominal subcutaneous fat and the muscle surrounding the viscera could be imaged in humans. While our imaging of visceral fat was not of sufficient quality, it was suggested that we will be able to develop a safe and practical abdominal fat scanner through future improvements.

Practical experimental certification of computational quantum gates using a twirling procedure.

PubMed

Moussa, Osama; da Silva, Marcus P; Ryan, Colm A; Laflamme, Raymond

2012-08-17

Because of the technical difficulty of building large quantum computers, it is important to be able to estimate how faithful a given implementation is to an ideal quantum computer. The common approach of completely characterizing the computation process via quantum process tomography requires an exponential amount of resources, and thus is not practical even for relatively small devices. We solve this problem by demonstrating that twirling experiments previously used to characterize the average fidelity of quantum memories efficiently can be easily adapted to estimate the average fidelity of the experimental implementation of important quantum computation processes, such as unitaries in the Clifford group, in a practical and efficient manner with applicability in current quantum devices. Using this procedure, we demonstrate state-of-the-art coherent control of an ensemble of magnetic moments of nuclear spins in a single crystal solid by implementing the encoding operation for a 3-qubit code with only a 1% degradation in average fidelity discounting preparation and measurement errors. We also highlight one of the advances that was instrumental in achieving such high fidelity control.

[Diagnostic possibilities of digital volume tomography].

PubMed

Lemkamp, Michael; Filippi, Andreas; Berndt, Dorothea; Lambrecht, J Thomas

2006-01-01

Cone beam computed tomography allows high quality 3D images of cranio-facial structures. Although detail resolution is increased, x-ray exposition is reduced compared to classic computer tomography. The volume is analysed in three orthogonal plains, which can be rotated independently without quality loss. Cone beam computed tomography seems to be a less expensive and less x-ray exposing alternative to classic computer tomography.

4D nano-tomography of electrochemical energy devices using lab-based X-ray imaging

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

Heenan, T. M. M.; Finegan, D. P.; Tjaden, B.

Electrochemical energy devices offer a variety of alternate means for low-carbon, multi-scale energy conversion and storage. Reactions in these devices are supported by electrodes with characteristically complex microstructures. To meet the increasing capacity and lifetime demands across a range of applications, it is essential to understand microstructural evolutions at a cell and electrode level which are thought to be critical aspects influencing material and device lifetime and performance. X-ray computed tomography (CT) has become a highly employed method for non-destructive characterisation of such microstructures with high spatial resolution. However, sub-micron resolutions present significant challenges for sample preparation and handling particularlymore » in 4D studies, (three spatial dimensions plus time). Here, microstructural information is collected from the same region of interest within two electrode materials: a solid oxide fuel cell and the positive electrode from a lithium-ion battery. Using a lab-based X-ray instrument, tomograms with sub-micron resolutions were obtained between thermal cycling. The intricate microstructural evolutions captured within these two materials provide model examples of 4D X-ray nano-CT capabilities in tracking challenging degradation mechanisms. This technique is valuable in the advancement of electrochemical research as well as broader applications for materials characterisation.« less

Quantitative Assessment of Optical Coherence Tomography Imaging Performance with Phantom-Based Test Methods And Computational Modeling

NASA Astrophysics Data System (ADS)

Agrawal, Anant

Optical coherence tomography (OCT) is a powerful medical imaging modality that uniquely produces high-resolution cross-sectional images of tissue using low energy light. Its clinical applications and technological capabilities have grown substantially since its invention about twenty years ago, but efforts have been limited to develop tools to assess performance of OCT devices with respect to the quality and content of acquired images. Such tools are important to ensure information derived from OCT signals and images is accurate and consistent, in order to support further technology development, promote standardization, and benefit public health. The research in this dissertation investigates new physical and computational models which can provide unique insights into specific performance characteristics of OCT devices. Physical models, known as phantoms, are fabricated and evaluated in the interest of establishing standardized test methods to measure several important quantities relevant to image quality. (1) Spatial resolution is measured with a nanoparticle-embedded phantom and model eye which together yield the point spread function under conditions where OCT is commonly used. (2) A multi-layered phantom is constructed to measure the contrast transfer function along the axis of light propagation, relevant for cross-sectional imaging capabilities. (3) Existing and new methods to determine device sensitivity are examined and compared, to better understand the detection limits of OCT. A novel computational model based on the finite-difference time-domain (FDTD) method, which simulates the physics of light behavior at the sub-microscopic level within complex, heterogeneous media, is developed to probe device and tissue characteristics influencing the information content of an OCT image. This model is first tested in simple geometric configurations to understand its accuracy and limitations, then a highly realistic representation of a biological cell, the retinal cone photoreceptor, is created and its resulting OCT signals studied. The phantoms and their associated test methods have successfully yielded novel types of data on the specific performance parameters of interest, which can feed standardization efforts within the OCT community. The level of signal detail provided by the computational model is unprecedented and gives significant insights into the effects of subcellular structures on OCT signals. Together, the outputs of this research effort serve as new tools in the toolkit to examine the intricate details of how and how well OCT devices produce information-rich images of biological tissue.

Anatomic Suitability for Transcaval Access Based on Computed Tomography.

PubMed

Lederman, Robert J; Greenbaum, Adam B; Rogers, Toby; Khan, Jaffar M; Fusari, Melissa; Chen, Marcus Y

2017-01-09

Transcaval access has been used successfully for over 200 transcatheter aortic valve replacements, large-bore percutaneous left ventricular assist devices, and thoracic endovascular aortic aneurysm repairs. This review teaches how to plan transcaval access and closure based on computed tomography. The main planning goals are to: 1) identify calcium-free crossing targets in the abdominal aorta along with optimal fluoroscopic projection angles and level with respect to lumbar vertebrae; 2) identify obstacles such as interposed bowel or pedunculated aortic atheroma; 3) plan covered stent bailout; and 4) identify jeopardized vascular branches such as renal arteries that might be obstructed by bailout covered stents if employed. The aorta and inferior vena cava are segmented (sculpted) using an image reconstruction workstation and crossing targets are highlighted. Important measurements such as aortic lumen diameter and target distance from renal arteries, aortoiliac bifurcation, and right femoral vein puncture site are reported to assist the operator. The proposed classification for transcaval feasibility has been revised, making some previously unfavorable candidates now feasible or favorable based on procedural success to date. Transcaval access allows percutaneous introduction of large devices into the aorta despite small or diseased iliofemoral arteries. By following these simplified procedures, both operators and imaging specialists can easily prepare comprehensive treatment plans. Copyright © 2017 American College of Cardiology Foundation. All rights reserved.

A measurement device for electromagnetic flow tomography

NASA Astrophysics Data System (ADS)

Vauhkonen, M.; Hänninen, A.; Lehtikangas, O.

2018-01-01

Electromagnetic flow meters have succesfully been used in many industries to measure the mean flow velocity of conductive liquids. This technology works reliably in single phase flows with axisymmetric flow profiles but can be inaccurate with asymmetric flows, which are encountered, for example, in multiphase flows, pipe elbows and T-junctions. Some computational techniques and measurement devices with multiple excitation coils and measurement electrodes have recently been proposed to be used in cases of asymmetric flows. In earlier studies, we proposed a computational approach for electromagnetic flow tomography (EMFT) for estimating velocity fields utilizing several excitation coils and a set of measurement electrodes attached to the surface of the pipe. This approach has been shown to work well with simulated data but has not been tested extensively with real measurements. In this paper, an EMFT system with four excitation coils and 16 measurement electrodes is introduced. The system is capable of using both square wave and sinusoidal coil current excitations and all the coils can be excited individually, also enabling parallel excitations with multiple frequencies. The studies undertaken in the paper demonstrate that the proposed EMFT system, together with the earlier introduced velocity field reconstruction approach, is capable of producing reliable velocify field estimates in a laboratory environment with both axisymmetric and asymmetric single phase flows.

Assessment of the primary stability of root analog zirconia implants designed using cone beam computed tomography software by means of the Periotest® device: An ex vivo study. A preliminary report.

PubMed

Matys, Jacek; Świder, Katarzyna; Flieger, Rafał; Dominiak, Marzena

2017-08-01

The implant primary stability is a fundamental prerequisite for a success of osseointegration process which determines the prosthetic reconstruction time. The aim of the present study was to assess the quality and precision of modern conical bone computer tomography (CBCT) software in preparing root analog zirconia implants (RAZIs) by measuring its primary stability by means of the Periotest device. Thirteen pig jaws with proper erupted first premolar (P1) teeth were used in the study. The CBCT examination was conducted in the area of the P1 tooth in each mandible. The 3-dimensional (3D) view of each tooth was designed from CBCT scan. The created 3D images were used to prepare root analog zirconia implants milled from a medical-grade zirconia block by means of laboratory milling. The RAZIs and titanium implants were placed into an alveolar socket after the tooth had been removed. The primary stability of the teeth before their extraction (G1), RAZIs (G2) and titanium implants (G3) were checked by Periotest devices. The mean results in PTV were: 15.9, 3.35, 12.7 for G1, G2 and G3 group, respectively. RAZIs during immediate loading achieved a significantly higher primary stability (lower Periotest value) as compared to the teeth and implants. The modern CBCT device allows us to design a precise image of an extracted tooth for the purpose of manufacturing a root analog implant. The additional feature of the surgical protocol using RAZI is the possibility of avoiding the augmentation procedure, which reduces the whole cost of the treatment.

Design and evaluation of a computed tomography (CT)-compatible needle insertion device using an electromagnetic tracking system and CT images.

PubMed

Shahriari, Navid; Hekman, Edsko; Oudkerk, Matthijs; Misra, Sarthak

2015-11-01

Percutaneous needle insertion procedures are commonly used for diagnostic and therapeutic purposes. Although current technology allows accurate localization of lesions, they cannot yet be precisely targeted. Lung cancer is the most common cause of cancer-related death, and early detection reduces the mortality rate. Therefore, suspicious lesions are tested for diagnosis by performing needle biopsy. In this paper, we have presented a novel computed tomography (CT)-compatible needle insertion device (NID). The NID is used to steer a flexible needle (φ0.55 mm) with a bevel at the tip in biological tissue. CT images and an electromagnetic (EM) tracking system are used in two separate scenarios to track the needle tip in three-dimensional space during the procedure. Our system uses a control algorithm to steer the needle through a combination of insertion and minimal number of rotations. Noise analysis of CT images has demonstrated the compatibility of the device. The results for three experimental cases (case 1: open-loop control, case 2: closed-loop control using EM tracking system and case 3: closed-loop control using CT images) are presented. Each experimental case is performed five times, and average targeting errors are 2.86 ± 1.14, 1.11 ± 0.14 and 1.94 ± 0.63 mm for case 1, case 2 and case 3, respectively. The achieved results show that our device is CT-compatible and it is able to steer a bevel-tipped needle toward a target. We are able to use intermittent CT images and EM tracking data to control the needle path in a closed-loop manner. These results are promising and suggest that it is possible to accurately target the lesions in real clinical procedures in the future.

Development of an oximeter for neurology

NASA Astrophysics Data System (ADS)

Aleinik, A.; Serikbekova, Z.; Zhukova, N.; Zhukova, I.; Nikitina, M.

2016-06-01

Cerebral desaturation can occur during surgery manipulation, whereas other parameters vary insignificantly. Prolonged intervals of cerebral anoxia can cause serious damage to the nervous system. Commonly used method for measurement of cerebral blood flow uses invasive catheters. Other techniques include single photon emission computed tomography (SPECT), positron emission tomography (PET), magnetic resonance imaging (MRI). Tomographic methods frequently use isotope administration, that may result in anaphylactic reactions to contrast media and associated nerve diseases. Moreover, the high cost and the need for continuous monitoring make it difficult to apply these techniques in clinical practice. Cerebral oximetry is a method for measuring oxygen saturation using infrared spectrometry. Moreover reflection pulse oximetry can detect sudden changes in sympathetic tone. For this purpose the reflectance pulse oximeter for use in neurology is developed. Reflectance oximeter has a definite advantage as it can be used to measure oxygen saturation in any part of the body. Preliminary results indicate that the device has a good resolution and high reliability. Modern applied schematics have improved device characteristics compared with existing ones.

Visualization of subcutaneous insulin injections by x-ray computed tomography

NASA Astrophysics Data System (ADS)

Thomsen, M.; Poulsen, M.; Bech, M.; Velroyen, A.; Herzen, J.; Beckmann, F.; Feidenhans'l, R.; Pfeiffer, F.

2012-11-01

We report how the three-dimensional structure of subcutaneous injections of soluble insulin can be visualized by x-ray computed tomography using an iodine based contrast agent. The injections investigated are performed ex vivo in porcine adipose tissue. Full tomography scans carried out at a laboratory x-ray source with a total acquisition time of about 1 min yield CT-images with an effective pixel size of 109 × 109 μm2. The depots are segmented using a modified Chan-Vese algorithm and we are able to observe differences in the shape of the injection depot and the position of the depot in the skin among equally performed injections. To overcome the beam hardening artefacts, which affect the quantitative prediction of the volume injected, we additionally present results concerning the visualization of two injections using synchrotron radiation. The spatial concentration distribution of iodine is calculated to show the dilution of the insulin drug inside the depot. Characterisation of the shape of the depot and the spatial concentration profile of the injected fluid is important knowledge when improving the clinical formulation of an insulin drug, the performance of injection devices and when predicting the effect of the drug through biomedical simulations.

Computed Tomography

NASA Astrophysics Data System (ADS)

Castellano, Isabel; Geleijns, Jacob

After its clinical introduction in 1973, computed tomography developed from an x-ray modality for axial imaging in neuroradiology into a versatile three dimensional imaging modality for a wide range of applications in for example oncology, vascular radiology, cardiology, traumatology and even in interventional radiology. Computed tomography is applied for diagnosis, follow-up studies and screening of healthy subpopulations with specific risk factors. This chapter provides a general introduction in computed tomography, covering a short history of computed tomography, technology, image quality, dosimetry, room shielding, quality control and quality criteria.

Do C-reactive protein level, white blood cell count, and pain location guide the selection of patients for computed tomography imaging in non-traumatic acute abdomen?

PubMed

Ozan, E; Atac, G K; Evrin, T; Alisar, K; Sonmez, L O; Alhan, A

2017-02-01

The value of abdominal computed tomography in non-traumatic abdominal pain has been well established. On the other hand, to manage computed tomography, appropriateness has become more of an issue as a result of the concomitant increase in patient radiation exposure with increased computed tomography use. The purpose of this study was to investigate whether C-reactive protein, white blood cell count, and pain location may guide the selection of patients for computed tomography in non-traumatic acute abdomen. Patients presenting with acute abdomen to the emergency department over a 12-month period and who subsequently underwent computed tomography were retrospectively reviewed. Those with serum C-reactive protein and white blood cell count measured on admission or within 24 h of the computed tomography were selected. Computed tomography examinations were retrospectively reviewed, and final diagnoses were designated either positive or negative for pathology relating to presentation with acute abdomen. White blood cell counts, C-reactive protein levels, and pain locations were analyzed to determine whether they increased or decreased the likelihood of producing a diagnostic computed tomography. The likelihood ratio for computed tomography positivity with a C-reactive protein level above 5 mg/L was 1.71, while this increased to 7.71 in patients with combined elevated C-reactive protein level and white blood cell count and right lower quadrant pain. Combined elevated C-reactive protein level and white blood cell count in patients with right lower quadrant pain may represent a potential factor that could guide the decision to perform computed tomography in non-traumatic acute abdomen.

Preoperative N Staging of Gastric Cancer by Stomach Protocol Computed Tomography

PubMed Central

Kim, Se Hoon; Kim, Jeong Jae; Lee, Jeong Sub; Kim, Seung Hyoung; Kim, Bong Soo; Maeng, Young Hee; Hyun, Chang Lim; Kim, Min Jeong

2013-01-01

Purpose Clinical stage of gastric cancer is currently assessed by computed tomography. Accurate clinical staging is important for the tailoring of therapy. This study evaluated the accuracy of clinical N staging using stomach protocol computed tomography. Materials and Methods Between March 2004 and November 2012, 171 patients with gastric cancer underwent preoperative stomach protocol computed tomography (Jeju National University Hospital; Jeju, Korea). Their demographic and clinical characteristics were reviewed retrospectively. Two radiologists evaluated cN staging using axial and coronal computed tomography images, and cN stage was matched with pathologic results. The diagnostic accuracy of stomach protocol computed tomography for clinical N staging and clinical characteristics associated with diagnostic accuracy were evaluated. Results The overall accuracy of stomach protocol computed tomography for cN staging was 63.2%. Computed tomography images of slice thickness 3.0 mm had a sensitivity of 60.0%; a specificity of 89.6%; an accuracy of 78.4%; and a positive predictive value of 78.0% in detecting lymph node metastases. Underestimation of cN stage was associated with larger tumor size (P<0.001), undifferentiated type (P=0.003), diffuse type (P=0.020), more advanced pathologic stage (P<0.001), and larger numbers of harvested and metastatic lymph nodes (P<0.001 each). Tumor differentiation was an independent factor affecting underestimation by computed tomography (P=0.045). Conclusions Computed tomography with a size criterion of 8 mm is highly specific but relatively insensitive in detecting nodal metastases. Physicians should keep in mind that computed tomography may not be an appropriate tool to detect nodal metastases for choosing appropriate treatment. PMID:24156034

A comparative approach to computer aided design model of a dog femur.

PubMed

Turamanlar, O; Verim, O; Karabulut, A

2016-01-01

Computer assisted technologies offer new opportunities in medical imaging and rapid prototyping in biomechanical engineering. Three dimensional (3D) modelling of soft tissues and bones are becoming more important. The accuracy of the analysis in modelling processes depends on the outline of the tissues derived from medical images. The aim of this study is the evaluation of the accuracy of 3D models of a dog femur derived from computed tomography data by using point cloud method and boundary line method on several modelling software. Solidworks, Rapidform and 3DSMax software were used to create 3D models and outcomes were evaluated statistically. The most accurate 3D prototype of the dog femur was created with stereolithography method using rapid prototype device. Furthermore, the linearity of the volumes of models was investigated between software and the constructed models. The difference between the software and real models manifests the sensitivity of the software and the devices used in this manner.

New diagnostic pathways urgently needed. Protocol of PET Guidance I pilot study: positron emission tomography in suspected cardiac implantable electronic device-related infection.

PubMed

Marciniak-Emmons, Marta Barbara; Sterliński, Maciej; Syska, Paweł; Maciąg, Aleksander; Farkowski, Michał Mirosław; Firek, Bohdan; Dziuk, Mirosław; Zając, Dariusz; Pytkowski, Mariusz; Szwed, Hanna

2016-01-01

Cardiovascular implantable electronic device (CIED) infection is a complication of increasing incidence. We present a protocol of an observational case control clinical trial "Positron Emission Tomography Combined With Computed Tomography (PET CT) in Suspected Cardiac Implantable Electronic Device Infection, a Pilot Study - PET Guidance I" (NCT02196753). The aim of this observational clinical trial is to assess and standardise diagnostic algorithms for CIED infections (lead-dependent infective endocarditis, generator pocket infection, fever of unknown origin) with PET CT in Poland. Study group will consist of 20 patients with initial diagnosis of CIED-related infection paired with a control group of 20 patients with implanted CIEDs, who underwent PET CT due to other non-infectious indications and have no data for infectious process in follow-up. All patients included in the study will undergo standard diagnostic pro-cess. Conventional/standard diagnostic and therapeutic process will consist of: medical interview, physical examination, laboratory tests, blood cultures; imaging studies: echocardiography: transthoracic (TTE), and, if there are no contraindications transoesophageal, computed tomography scan for pulmonary embolism if indicated; if there are abnormalities in other systems, decisions concerning further diagnostics will be made at the physician's discretion. As well as standard diagnostic procedures, patients will undergo whole body PET CT scan to localise infection or inflammation. Diagnosis and therapeutic decision will be obtained from the Study Committee. Follow-up will be held within six months with control visits at three and six months. During each follow-up visit, all patients will undergo laboratory tests, two blood cultures collected 1 h apart, and TTE. In case of actual clinical suspicion of infective endocarditis or local generator pocket infection, patients will be referred for further diagnostics. Endpoints for the results assessment - primary endpoints are to standardise PET CT in the diagnostic process: sensitivity, specificity, positive predictive value, and negative predictive value of the diagnosis made by PET CT; secondary endpoints are: assessment of usefulness of PET CT for detection of remote infective complications (metastatic abscesses, infected pulmonary emboli), incidence of particular localisations of infection, influence of PET CT on therapeutic decision: confirmation or change of decision based on PET CT, safety and complications of diagnostic process of CIED-related infections with PET CT. Evaluation of PET CT use for device-related infections in a case control study may be conclusive and improve diagnostic pathway.

Radiochemistry, PET Imaging, and the Internet of Chemical Things

PubMed Central

2016-01-01

The Internet of Chemical Things (IoCT), a growing network of computers, mobile devices, online resources, software suites, laboratory equipment, synthesis apparatus, analytical devices, and a host of other machines, all interconnected to users, manufacturers, and others through the infrastructure of the Internet, is changing how we do chemistry. While in its infancy across many chemistry laboratories and departments, it became apparent when considering our own work synthesizing radiopharmaceuticals for positron emission tomography (PET) that a more mature incarnation of the IoCT already exists. How does the IoCT impact our lives today, and what does it hold for the smart (radio)chemical laboratories of the future? PMID:27610410

Radiochemistry, PET Imaging, and the Internet of Chemical Things.

PubMed

Thompson, Stephen; Kilbourn, Michael R; Scott, Peter J H

2016-08-24

The Internet of Chemical Things (IoCT), a growing network of computers, mobile devices, online resources, software suites, laboratory equipment, synthesis apparatus, analytical devices, and a host of other machines, all interconnected to users, manufacturers, and others through the infrastructure of the Internet, is changing how we do chemistry. While in its infancy across many chemistry laboratories and departments, it became apparent when considering our own work synthesizing radiopharmaceuticals for positron emission tomography (PET) that a more mature incarnation of the IoCT already exists. How does the IoCT impact our lives today, and what does it hold for the smart (radio)chemical laboratories of the future?

Shift focal spot X-ray tube to the imposition anode under long exposure

NASA Astrophysics Data System (ADS)

Obodovskiy, A. V.; Bessonov, V. B.; Larionov, I. A.

2018-02-01

X-ray non-destructive testing is an integral part of any modern industrial production. Microfocus X-ray sources make it possible to obtain projected images with an increased spatial resolution by using a direct geometric magnification during the survey. On the basis of the St. Petersburg State Electrotechnical University staff of the department of electronic devices and equipment has been designed model of microfocus X-ray computed tomography.

Infective endocarditis in children: an update.

PubMed

Dixon, Garth; Christov, Georgi

2017-06-01

Infective endocarditis in children remains a clinical challenge. Here, we review the impact of the updated 2015 American Heart Association and European Society of Cardiology guidelines on management as well as the significance of the new predisposing factors, diagnostic and treatment options, and the impact of the 2007-2008 change in prophylaxis recommendations. The new 2015 infective endocarditis guidelines introduced the endocarditis team, added the new imaging modalities of computer tomography and PET-computer tomography into the diagnostic criteria and endorsed the concept of safety of relatively early surgical treatment. The impact of the restriction of infective endocarditis prophylaxis since the 2007-2008 American Heart Association and National Institute for Health and Care Excellence recommendations is uncertain, with some studies showing no change and other more recent studies showing increased incidence. The difficulties in adjusting for varying confounding factors are discussed. The relative proportion of the device-related infective endocarditis is increasing. Special attention is paid to relatively high incidence of percutaneous pulmonary valve implantation-related infective endocarditis with low proportion of positive echo signs, disproportionate shift in causative agents, and unusual complication of acute obstruction. The significance of incomplete neoendothelialization on the risk of infective endocarditis on intracardiac devices is also discussed. The impact of changes in the infective endocarditis prophylaxis recommendations in pediatric patients is still uncertain. The device-related infective endocarditis has increasing importance, with the incidence on transcatheter implanted bovine jugular vein pulmonary valves being relatively high. The use of novel imaging, laboratory diagnostic techniques, and relatively early surgery in particular circumstances is important for management of paediatric infective endocarditis.

Proof of Concept Study for the Design, Manufacturing, and Testing of a Patient-Specific Shape Memory Device for Treatment of Unicoronal Craniosynostosis.

PubMed

Borghi, Alessandro; Rodgers, Will; Schievano, Silvia; Ponniah, Allan; Jeelani, Owase; Dunaway, David

2018-01-01

Treatment of unicoronal craniosynostosis is a surgically challenging problem, due to the involvement of coronal suture and cranial base, with complex asymmetries of the calvarium and orbit. Several techniques for correction have been described, including surgical bony remodeling, early strip craniotomy with orthotic helmet remodeling and distraction. Current distraction devices provide unidirectional forces and have had very limited success. Nitinol is a shape memory alloy that can be programmed to the shape of a patient-specific anatomy by means of thermal treatment.In this work, a methodology to produce a nitinol patient-specific distractor is presented: computer tomography images of a 16-month-old patient with unicoronal craniosynostosis were processed to create a 3-dimensional model of his skull and define the ideal shape postsurgery. A mesh was produced from a nitinol sheet, formed to the ideal skull shape and heat treated to be malleable at room temperature. The mesh was afterward deformed to be attached to a rapid prototyped plastic skull, replica of the patient initial anatomy. The mesh/skull construct was placed in hot water to activate the mesh shape memory property: the deformed plastic skull was computed tomography scanned for comparison of its shape with the initial anatomy and with the desired shape, showing that the nitinol mesh had been able to distract the plastic skull to a shape close to the desired one.The shape-memory properties of nitinol allow for the design and production of patient-specific devices able to deliver complex, preprogrammable shape changes.

Translation of First North American 50 and 70 cc Total Artificial Heart Virtual and Clinical Implantations: Utility of 3D Computed Tomography to Test Fit Devices.

PubMed

Ferng, Alice S; Oliva, Isabel; Jokerst, Clinton; Avery, Ryan; Connell, Alana M; Tran, Phat L; Smith, Richard G; Khalpey, Zain

2017-08-01

Since the creation of SynCardia's 50 cc Total Artificial Hearts (TAHs), patients with irreversible biventricular failure now have two sizing options. Herein, a case series of three patients who have undergone successful 50 and 70 cc TAH implantation with complete closure of the chest cavity utilizing preoperative "virtual implantation" of different sized devices for surgical planning are presented. Computed tomography (CT) images were used for preoperative planning prior to TAH implantation. Three-dimensional (3D) reconstructions of preoperative chest CT images were generated and both 50 and 70 cc TAHs were virtually implanted into patients' thoracic cavities. During the simulation, the TAHs were projected over the native hearts in a similar position to the actual implantation, and the relationship between the devices and the atria, ventricles, chest wall, and diaphragm were assessed. The 3D reconstructed images and virtual modeling were used to simulate and determine for each patient if the 50 or 70 cc TAH would have a higher likelihood of successful implantation without complications. Subsequently, all three patients received clinical implants of the properly sized TAH based on virtual modeling, and their chest cavities were fully closed. This virtual implantation increases our confidence that the selected TAH will better fit within the thoracic cavity allowing for improved surgical outcome. Clinical implantation of the TAHs showed that our virtual modeling was an effective method for determining the correct fit and sizing of 50 and 70 cc TAHs. © 2016 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Computed tomography vs. digital radiography assessment for detection of osteolysis in asymptomatic patients with uncemented cups: a proposal for a new classification system based on computer tomography.

PubMed

Sandgren, Buster; Crafoord, Joakim; Garellick, Göran; Carlsson, Lars; Weidenhielm, Lars; Olivecrona, Henrik

2013-10-01

Digital radiographic images in the anterior-posterior and lateral view have been gold standard for evaluation of peri-acetabular osteolysis for patients with an uncemented hip replacement. We compared digital radiographic images and computer tomography in detection of peri-acetabular osteolysis and devised a classification system based on computer tomography. Digital radiographs were compared with computer tomography on 206 hips, with a mean follow up 10 years after surgery. The patients had no clinical signs of osteolysis and none were planned for revision surgery. On digital radiographs, 192 cases had no osteolysis and only 14 cases had osteolysis. When using computer tomography there were 184 cases showing small or large osteolysis and only 22 patients had no osteolysis. A classification system for peri-acetabular osteolysis is proposed based on computer tomography that is easy to use on standard follow up evaluation. Copyright © 2013 Elsevier Inc. All rights reserved.

Updating a preoperative surface model with information from real-time tracked 2D ultrasound using a Poisson surface reconstruction algorithm

NASA Astrophysics Data System (ADS)

Sun, Deyu; Rettmann, Maryam E.; Holmes, David R.; Linte, Cristian A.; Packer, Douglas; Robb, Richard A.

2014-03-01

In this work, we propose a method for intraoperative reconstruction of a left atrial surface model for the application of cardiac ablation therapy. In this approach, the intraoperative point cloud is acquired by a tracked, 2D freehand intra-cardiac echocardiography device, which is registered and merged with a preoperative, high resolution left atrial surface model built from computed tomography data. For the surface reconstruction, we introduce a novel method to estimate the normal vector of the point cloud from the preoperative left atrial model, which is required for the Poisson Equation Reconstruction algorithm. In the current work, the algorithm is evaluated using a preoperative surface model from patient computed tomography data and simulated intraoperative ultrasound data. Factors such as intraoperative deformation of the left atrium, proportion of the left atrial surface sampled by the ultrasound, sampling resolution, sampling noise, and registration error were considered through a series of simulation experiments.

Fine Output Voltage Control Method considering Time-Delay of Digital Inverter System for X-ray Computed Tomography

NASA Astrophysics Data System (ADS)

Shibata, Junji; Kaneko, Kazuhide; Ohishi, Kiyoshi; Ando, Itaru; Ogawa, Mina; Takano, Hiroshi

This paper proposes a new output voltage control for an inverter system, which has time-delay and nonlinear load. In the next generation X-ray computed tomography of a medical device (X-ray CT) that uses the contactless power transfer method, the feedback signal often contains time-delay due to AD/DA conversion and error detection/correction time. When the PID controller of the inverter system is received the adverse effects of the time-delay, the controller often has an overshoot and a oscillated response. In order to overcome this problem, this paper proposes a compensation method based on the Smith predictor for an inverter system having a time-delay and the nonlinear loads which are the diode bridge rectifier and X-ray tube. The proposed compensation method consists of the hybrid Smith predictor system based on an equivalent analog circuit and DSP. The experimental results confirm the validity of the proposed system.

Assessment of the Role of Different Imaging Modalities with Emphasis on Fdg Pet/Ct in the Management of Well Differentiated Thyroid Cancer (WDTC).

PubMed

Kendi A, Tuba Karagulle; Mudalegundi, Shwetha; Switchenko, Jeffrey; Lee, Daniel; Halkar, Raghuveer; Chen, Amy Y

2016-01-01

Positron emission tomography/computed tomography is suggested to have a role in detection of iodine negative recurrence in well differentiated thyroid cancer. The aim of this study is to identify role of different imaging modalities in the management of well differentiated thyroid cancer. We reviewed 900 well differentiated thyroid cancer patients after post-thyroidectomy who underwent recombinant human thyroid stimulating hormone stimulated Sodium Iodide I 131 imaging. Out of 900 patients, 74 had positron emission tomography/computed tomography. Multivariate analysis was performed by controlling positron emission tomography/computed tomography, Sodium Iodide I 131 scan, neck ultrasonography, age, sex, primary tumor size, stage, histology, thyroglobulin. Patients were grouped according to results of Sodium Iodide I 131 scan and positron emission tomography/computed tomography. Positron emission tomography/computed tomography was positive in 23 of 74 patients. The sensitivity for positron emission tomography was 11/11(100%), the specificity was 51/63 (81.0%), the positive predictive value was 11/23 (47.8%), and the negative predictive value was 51/51 (100%). The sensitivity for the neck ultrasonography was 4/8 (50%), the specificity was 53/60 (88.3%), positive predictive value was 4/11 (36.4%), and negative predictive value was 53/57 (93.0%). 50% of patients who had Sodium Iodide I 131 negative scan and positive positron emission tomography/computed tomography had a change in management. Thirty-six percent with positive neck ultrasonography had a change in management. Out of 11 recurrences, 6 had distant metastatic disease, and 5/11 had regional nodal disease. Neck ultrasonography showed nodal metastasis in 4/5 (80%). Positron emission tomography/computed tomography altered management in the presence of a high thyroglobulin level and a negative Sodium Iodide I 131 scan. Neck ultrasonography should be the first line of imaging with rising thyroglobulin levels. Positron emission tomography/computed tomography should be considered for cases with high thyroglobulin levels and normal neck ultrasonography to look for distant metastatic disease.

Tracked 3D ultrasound in radio-frequency liver ablation

NASA Astrophysics Data System (ADS)

Boctor, Emad M.; Fichtinger, Gabor; Taylor, Russell H.; Choti, Michael A.

2003-05-01

Recent studies have shown that radio frequency (RF) ablation is a simple, safe and potentially effective treatment for selected patients with liver metastases. Despite all recent therapeutic advancements, however, intra-procedural target localization and precise and consistent placement of the tissue ablator device are still unsolved problems. Various imaging modalities, including ultrasound (US) and computed tomography (CT) have been tried as guidance modalities. Transcutaneous US imaging, due to its real-time nature, may be beneficial in many cases, but unfortunately, fails to adequately visualize the tumor in many cases. Intraoperative or laparoscopic US, on the other hand, provides improved visualization and target imaging. This paper describes a system for computer-assisted RF ablation of liver tumors, combining navigational tracking of a conventional imaging ultrasound probe to produce 3D ultrasound imaging with a tracked RF ablation device supported by a passive mechanical arm and spatially registered to the ultrasound volume.

Deep brain stimulation with a pre-existing cochlear implant: Surgical technique and outcome.

PubMed

Eddelman, Daniel; Wewel, Joshua; Wiet, R Mark; Metman, Leo V; Sani, Sepehr

2017-01-01

Patients with previously implanted cranial devices pose a special challenge in deep brain stimulation (DBS) surgery. We report the implantation of bilateral DBS leads in a patient with a cochlear implant. Technical nuances and long-term interdevice functionality are presented. A 70-year-old patient with advancing Parkinson's disease and a previously placed cochlear implant for sensorineural hearing loss was referred for placement of bilateral DBS in the subthalamic nucleus (STN). Prior to DBS, the patient underwent surgical removal of the subgaleal cochlear magnet, followed by stereotactic MRI, frame placement, stereotactic computed tomography (CT), and merging of imaging studies. This technique allowed for successful computational merging, MRI-guided targeting, and lead implantation with acceptable accuracy. Formal testing and programming of both the devices were successful without electrical interference. Successful DBS implantation with high resolution MRI-guided targeting is technically feasible in patients with previously implanted cochlear implants by following proper precautions.

Muon tomography of the Soufrière of Guadeloupe (Lesser Antilles): Comparison with other geophysical imaging methods and assessment of volcanic risks

NASA Astrophysics Data System (ADS)

Gibert, D.; Lesparre, N.; Marteau, J.; Taisne, B.; Nicollin, F.; Coutant, O.

2011-12-01

Density tomography of rock with muons of cosmic origin measures the attenuation of the flux of particles crossing the object of interest to derive its opacity, i.e. the quantity of matter encountered by the particles along their trajectories. Recent progress in micro-electronics and particle detectors make field measurement possible and muon density tomography is gaining a growing interest (e.g. Tanaka et al., 2010; Gibert et al., 2010). We have constructed field telescopes based on the detectors of the OPERA experiment devoted to study neutrino oscillation (Lesparre et al., 2011a). Each telescope may be equipped with a variable number of detection matrices with 256 pixels. The spatial resolution is adaptable and is typically of about 20 meters (Lesparre et al., 2010). The telescopes are portable autonomous devices able to operate in harsh field conditions encountered on tropical volcanoes. The total power consumption is less than 40W, and an Ethernet link allows data downloading and remote control of the electronic devices and on-board computers. Larger high-resolution telescopes are under construction. The instruments have been successfully tested on the Etna and Soufrière of Guadeloupe volcanoes were a telescope is operating continuously since Summer 2010. Muon radiographies of the Soufrière lava dome reveal its very heterogeneous density structure produced by an intense hydrothermal circulation of acid fluids which alters its mechanical integrity leading to a high risk level of destabilisation. Small-size features are visible on the images and provide precious informations on the structure of the upper hydrothermal systems. Joined interpretation with other geophysical data available on the Soufrière - seismic tomography, electrical resistivity tomography, gravity data - is presented and discussed. Density muon tomography of the internal structure of volcanoes like the Soufrière brings important informations for the hazard evaluation an is particularly adapted to brought constraints on flank destabilization and hydrothermal circulation models. Tanaka et al., Three dimensional computational axial tomography scan of a volcano with cosmic ray muon radiography, J. Geophys. Res., 115, B12332, doi:10.1029/2010JB007677, 2010. Gibert et al., Muon Tomography: Plans for Observations in the Lesser Antilles, Earth Planets and Space, Vol. 52, 153-165, doi: 10.5047/eps.2009.07.003, 2010. Lesparre et al., Geophysical muon imaging: feasibility and limits, Geophysical Journal International, Vol. 183, 1348-1361, doi: 10.1111/j.1365-246X.2010.04790.x, 2010. Lesparre et al., Design and Operation of a Field Telescope for Cosmic Ray Geophysical Tomography, Nuclear Instruments and Methods in Physics Research A, to appear, 2011a. Lesparre et al., Bayesian Dual Inversion of Experimental Telescope Acceptance and Integrated Flux for Geophysical Muon Tomography, Geophysical Journal International, to appear, 2011b.

Body CT (CAT Scan)

MedlinePlus

... Resources Professions Site Index A-Z Computed Tomography (CT) - Body Computed tomography (CT) of the body uses ... of CT Scanning of the Body? What is CT Scanning of the Body? Computed tomography, more commonly ...

68Ga/177Lu-labeled DOTA-TATE shows similar imaging and biodistribution in neuroendocrine tumor model.

PubMed

Liu, Fei; Zhu, Hua; Yu, Jiangyuan; Han, Xuedi; Xie, Qinghua; Liu, Teli; Xia, Chuanqin; Li, Nan; Yang, Zhi

2017-06-01

Somatostatin receptors are overexpressed in neuroendocrine tumors, whose endogenous ligands are somatostatin. DOTA-TATE is an analogue of somatostatin, which shows high binding affinity to somatostatin receptors. We aim to evaluate the 68 Ga/ 177 Lu-labeling DOTA-TATE kit in neuroendocrine tumor model for molecular imaging and to try human-positron emission tomography/computed tomography imaging of 68 Ga-DOTA-TATE in neuroendocrine tumor patients. DOTA-TATE kits were formulated and radiolabeled with 68 Ga/ 177 Lu for 68 Ga/ 177 Lu-DOTA-TATE (M-DOTA-TATE). In vitro and in vivo stability of 177 Lu-DOTA-TATE were performed. Nude mice bearing human tumors were injected with 68 Ga-DOTA-TATE or 177 Lu-DOTA-TATE for micro-positron emission tomography and micro-single-photon emission computed tomography/computed tomography imaging separately, and clinical positron emission tomography/computed tomography images of 68 Ga-DOTA-TATE were obtained at 1 h post-intravenous injection from patients with neuroendocrine tumors. Micro-positron emission tomography and micro-single-photon emission computed tomography/computed tomography imaging of 68 Ga-DOTA-TATE and 177 Lu-DOTA-TATE both showed clear tumor uptake which could be blocked by excess DOTA-TATE. In addition, 68 Ga-DOTA-TATE-positron emission tomography/computed tomography imaging in neuroendocrine tumor patients could show primary and metastatic lesions. 68 Ga-DOTA-TATE and 177 Lu-DOTA-TATE could accumulate in tumors in animal models, paving the way for better clinical peptide receptor radionuclide therapy for neuroendocrine tumor patients in Asian population.

Clinical cone beam computed tomography compared to high-resolution peripheral computed tomography in the assessment of distal radius bone.

PubMed

de Charry, C; Boutroy, S; Ellouz, R; Duboeuf, F; Chapurlat, R; Follet, H; Pialat, J B

2016-10-01

Clinical cone beam computed tomography (CBCT) was compared to high-resolution peripheral quantitative computed tomography (HR-pQCT) for the assessment of ex vivo radii. Strong correlations were found for geometry, volumetric density, and trabecular structure. Using CBCT, bone architecture assessment was feasible but compared to HR-pQCT, trabecular parameters were overestimated whereas cortical ones were underestimated. HR-pQCT is the most widely used technique to assess bone microarchitecture in vivo. Yet, this technology has been only applicable at peripheral sites, in only few research centers. Clinical CBCT is more widely available but quantitative assessment of the bone structure is usually not performed. We aimed to compare the assessment of bone structure with CBCT (NewTom 5G, QR, Verona, Italy) and HR-pQCT (XtremeCT, Scanco Medical AG, Brüttisellen, Switzerland). Twenty-four distal radius specimens were scanned with these two devices with a reconstructed voxel size of 75 μm for Newtom 5G and 82 μm for XtremeCT, respectively. A rescaling-registration scheme was used to define the common volume of interest. Cortical and trabecular compartments were separated using a semiautomated double contouring method. Density and microstructure were assessed with the HR-pQCT software on both modality images. Strong correlations were found for geometry parameters (r = 0.98-0.99), volumetric density (r = 0.91-0.99), and trabecular structure (r = 0.94-0.99), all p < 0.001. Correlations were lower for cortical microstructure (r = 0.80-0.89), p < 0.001. However, absolute differences were observed between modalities for all parameters, with an overestimation of the trabecular structure (trabecular number, 1.62 ± 0.37 vs. 1.47 ± 0.36 mm(-1)) and an underestimation of the cortical microstructure (cortical porosity, 3.3 ± 1.3 vs. 4.4 ± 1.4 %) assessed on CBCT images compared to HR-pQCT images. Clinical CBCT devices are able to analyze large portions of distal bones with good spatial resolution and limited irradiation. However, compared to dedicated HR-pQCT, the assessment of microarchitecture by NewTom 5G dental CBCT showed some discrepancies, for density measurements mainly. Further technical developments are required to reach optimal assessment of bone characteristics.

Stereolithography: a potential new tool in forensic medicine.

PubMed

Dolz, M S; Cina, S J; Smith, R

2000-06-01

Stereolithography is a computer-mediated method that can be used to quickly create anatomically correct three-dimensional epoxy and acrylic resin models from various types of medical data. Multiple imaging modalities can be exploited, including computed tomography and magnetic resonance imaging. The technology was first developed and used in 1986 to overcome limitations in previous computer-aided manufacturing/milling techniques. Stereolithography is presently used to accurately reproduce both the external and internal anatomy of body structures. Current medical uses of stereolithography include preoperative planning of orthopedic and maxillofacial surgeries, the fabrication of custom prosthetic devices; and the assessment of the degree of bony and soft-tissue injury caused by trauma. We propose that there is a useful, as yet untapped, potential for this technology in forensic medicine.

Excess of Radiation Burden for Young Testicular Cancer Patients using Automatic Exposure Control and Contrast Agent on Whole-body Computed Tomography Imaging.

PubMed

Niiniviita, Hannele; Kulmala, Jarmo; Pölönen, Tuukka; Määttänen, Heli; Järvinen, Hannu; Salminen, Eeva

2017-06-01

The aim of the study was to assess patient dose from whole-body computed tomography (CT) in association with patient size, automatic exposure control (AEC) and intravenous (IV) contrast agent. Sixty-five testicular cancer patients (mean age 28 years) underwent altogether 279 whole-body CT scans from April 2000 to April 2011. The mean number of repeated examinations was 4.3. The GE LightSpeed 16 equipped with AEC and the Siemens Plus 4 CT scanners were used for imaging. Whole-body scans were performed with (216) and without (63) IV contrast. The ImPACT software was used to determine the effective and organ doses. Patient doses were independent (p < 0.41) of patient size when the Plus 4 device (mean 7.4 mSv, SD 1.7 mSv) was used, but with the LightSpeed 16 AEC device, the dose (mean 14 mSv, SD 4.6 mSv) increased significantly (p < 0.001) with waist cirfumference. Imaging with the IV contrast agent caused significantly higher (13% Plus 4, 35% LightSpeed 16) exposure than non-contrast imaging (p < 0.001). Great caution on the use of IV contrast agent and careful set-up of the AEC modulation parameters is recommended to avoid excessive radiation exposure on the whole-body CT imaging of young patients.

Degrees of reality: airway anatomy of high-fidelity human patient simulators and airway trainers.

PubMed

Schebesta, Karl; Hüpfl, Michael; Rössler, Bernhard; Ringl, Helmut; Müller, Michael P; Kimberger, Oliver

2012-06-01

Human patient simulators and airway training manikins are widely used to train airway management skills to medical professionals. Furthermore, these patient simulators are employed as standardized "patients" to evaluate airway devices. However, little is known about how realistic these patient simulators and airway-training manikins really are. This trial aimed to evaluate the upper airway anatomy of four high-fidelity patient simulators and two airway trainers in comparison with actual patients by means of radiographic measurements. The volume of the pharyngeal airspace was the primary outcome parameter. Computed tomography scans of 20 adult trauma patients without head or neck injuries were compared with computed tomography scans of four high-fidelity patient simulators and two airway trainers. By using 14 predefined distances, two cross-sectional areas and three volume parameters of the upper airway, the manikins' similarity to a human patient was assessed. The pharyngeal airspace of all manikins differed significantly from the patients' pharyngeal airspace. The HPS Human Patient Simulator (METI®, Sarasota, FL) was the most realistic high-fidelity patient simulator (6/19 [32%] of all parameters were within the 95% CI of human airway measurements). The airway anatomy of four high-fidelity patient simulators and two airway trainers does not reflect the upper airway anatomy of actual patients. This finding may impact airway training and confound comparative airway device studies.

Full-field fan-beam x-ray fluorescence computed tomography system design with linear-array detectors and pinhole collimation: a rapid Monte Carlo study

NASA Astrophysics Data System (ADS)

Zhang, Siyuan; Li, Liang; Li, Ruizhe; Chen, Zhiqiang

2017-11-01

We present the design concept and initial simulations for a polychromatic full-field fan-beam x-ray fluorescence computed tomography (XFCT) device with pinhole collimators and linear-array photon counting detectors. The phantom is irradiated by a fan-beam polychromatic x-ray source filtered by copper. Fluorescent photons are stimulated and then collected by two linear-array photon counting detectors with pinhole collimators. The Compton scatter correction and the attenuation correction are applied in the data processing, and the maximum-likelihood expectation maximization algorithm is applied for the image reconstruction of XFCT. The physical modeling of the XFCT imaging system was described, and a set of rapid Monte Carlo simulations was carried out to examine the feasibility and sensitivity of the XFCT system. Different concentrations of gadolinium (Gd) and gold (Au) solutions were used as contrast agents in simulations. Results show that 0.04% of Gd and 0.065% of Au can be well reconstructed with the full scan time set at 6 min. Compared with using the XFCT system with a pencil-beam source or a single-pixel detector, using a full-field fan-beam XFCT device with linear-array detectors results in significant scanning time reduction and may satisfy requirements of rapid imaging, such as in vivo imaging experiments.

Dual-Energy Computed Tomography in Cardiothoracic Vascular Imaging.

PubMed

De Santis, Domenico; Eid, Marwen; De Cecco, Carlo N; Jacobs, Brian E; Albrecht, Moritz H; Varga-Szemes, Akos; Tesche, Christian; Caruso, Damiano; Laghi, Andrea; Schoepf, Uwe Joseph

2018-07-01

Dual energy computed tomography is becoming increasingly widespread in clinical practice. It can expand on the traditional density-based data achievable with single energy computed tomography by adding novel applications to help reach a more accurate diagnosis. The implementation of this technology in cardiothoracic vascular imaging allows for improved image contrast, metal artifact reduction, generation of virtual unenhanced images, virtual calcium subtraction techniques, cardiac and pulmonary perfusion evaluation, and plaque characterization. The improved diagnostic performance afforded by dual energy computed tomography is not associated with an increased radiation dose. This review provides an overview of dual energy computed tomography cardiothoracic vascular applications. Copyright © 2018 Elsevier Inc. All rights reserved.

CT to Cone-beam CT Deformable Registration With Simultaneous Intensity Correction

PubMed Central

Zhen, Xin; Gu, Xuejun; Yan, Hao; Zhou, Linghong; Jia, Xun; Jiang, Steve B.

2012-01-01

Computed tomography (CT) to cone-beam computed tomography (CBCT) deformable image registration (DIR) is a crucial step in adaptive radiation therapy. Current intensity-based registration algorithms, such as demons, may fail in the context of CT-CBCT DIR because of inconsistent intensities between the two modalities. In this paper, we propose a variant of demons, called Deformation with Intensity Simultaneously Corrected (DISC), to deal with CT-CBCT DIR. DISC distinguishes itself from the original demons algorithm by performing an adaptive intensity correction step on the CBCT image at every iteration step of the demons registration. Specifically, the intensity correction of a voxel in CBCT is achieved by matching the first and the second moments of the voxel intensities inside a patch around the voxel with those on the CT image. It is expected that such a strategy can remove artifacts in the CBCT image, as well as ensuring the intensity consistency between the two modalities. DISC is implemented on computer graphics processing units (GPUs) in compute unified device architecture (CUDA) programming environment. The performance of DISC is evaluated on a simulated patient case and six clinical head-and-neck cancer patient data. It is found that DISC is robust against the CBCT artifacts and intensity inconsistency and significantly improves the registration accuracy when compared with the original demons. PMID:23032638

3D analysis of semiconductor devices: A combination of 3D imaging and 3D elemental analysis

NASA Astrophysics Data System (ADS)

Fu, Bianzhu; Gribelyuk, Michael A.

2018-04-01

3D analysis of semiconductor devices using a combination of scanning transmission electron microscopy (STEM) Z-contrast tomography and energy dispersive spectroscopy (EDS) elemental tomography is presented. 3D STEM Z-contrast tomography is useful in revealing the depth information of the sample. However, it suffers from contrast problems between materials with similar atomic numbers. Examples of EDS elemental tomography are presented using an automated EDS tomography system with batch data processing, which greatly reduces the data collection and processing time. 3D EDS elemental tomography reveals more in-depth information about the defect origin in semiconductor failure analysis. The influence of detector shadowing and X-rays absorption on the EDS tomography's result is also discussed.

Impact of cardiac support device combined with slow-release prostacyclin agonist in a canine ischemic cardiomyopathy model.

PubMed

Kubota, Yasuhiko; Miyagawa, Shigeru; Fukushima, Satsuki; Saito, Atsuhiro; Watabe, Hiroshi; Daimon, Takashi; Sakai, Yoshiki; Akita, Toshiaki; Sawa, Yoshiki

2014-03-01

The cardiac support device supports the heart and mechanically reduces left ventricular (LV) diastolic wall stress. Although it has been shown to halt LV remodeling in dilated cardiomyopathy, its therapeutic efficacy is limited by its lack of biological effects. In contrast, the slow-release synthetic prostacyclin agonist ONO-1301 enhances reversal of LV remodeling through biological mechanisms such as angiogenesis and attenuation of fibrosis. We therefore hypothesized that ONO-1301 plus a cardiac support device might be beneficial for the treatment of ischemic cardiomyopathy. Twenty-four dogs with induced anterior wall infarction were assigned randomly to 1 of 4 groups at 1 week postinfarction as follows: cardiac support device alone, cardiac support device plus ONO-1301 (hybrid therapy), ONO-1301 alone, or sham control. At 8 weeks post-infarction, LV wall stress was reduced significantly in the hybrid therapy group compared with the other groups. Myocardial blood flow, measured by positron emission tomography, and vascular density were significantly higher in the hybrid therapy group compared with the cardiac support device alone and sham groups. The hybrid therapy group also showed the least interstitial fibrosis, the greatest recovery of LV systolic and diastolic functions, assessed by multidetector computed tomography and cardiac catheterization, and the lowest plasma N-terminal pro-B-type natriuretic peptide levels (P < .05). The combination of a cardiac support device and the prostacyclin agonist ONO-1301 elicited a greater reversal of LV remodeling than either treatment alone, suggesting the potential of this hybrid therapy for the clinical treatment of ischemia-induced heart failure. Copyright © 2014 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

A Freeware Path to Neutron Computed Tomography

NASA Astrophysics Data System (ADS)

Schillinger, Burkhard; Craft, Aaron E.

Neutron computed tomography has become a routine method at many neutron sources due to the availability of digital detection systems, powerful computers and advanced software. The commercial packages Octopus by Inside Matters and VGStudio by Volume Graphics have been established as a quasi-standard for high-end computed tomography. However, these packages require a stiff investment and are available to the users only on-site at the imaging facility to do their data processing. There is a demand from users to have image processing software at home to do further data processing; in addition, neutron computed tomography is now being introduced even at smaller and older reactors. Operators need to show a first working tomography setup before they can obtain a budget to build an advanced tomography system. Several packages are available on the web for free; however, these have been developed for X-rays or synchrotron radiation and are not immediately useable for neutron computed tomography. Three reconstruction packages and three 3D-viewers have been identified and used even for Gigabyte datasets. This paper is not a scientific publication in the classic sense, but is intended as a review to provide searchable help to make the described packages usable for the tomography community. It presents the necessary additional preprocessing in ImageJ, some workarounds for bugs in the software, and undocumented or badly documented parameters that need to be adapted for neutron computed tomography. The result is a slightly complicated, but surprisingly high-quality path to neutron computed tomography images in 3D, but not a replacement for the even more powerful commercial software mentioned above.

Time of flight imaging through scattering environments (Conference Presentation)

NASA Astrophysics Data System (ADS)

Le, Toan H.; Breitbach, Eric C.; Jackson, Jonathan A.; Velten, Andreas

2017-02-01

Light scattering is a primary obstacle to imaging in many environments. On small scales in biomedical microscopy and diffuse tomography scenarios scattering is caused by tissue. On larger scales scattering from dust and fog provide challenges to vision systems for self driving cars and naval remote imaging systems. We are developing scale models for scattering environments and investigation methods for improved imaging particularly using time of flight transient information. With the emergence of Single Photon Avalanche Diode detectors and fast semiconductor lasers, illumination and capture on picosecond timescales are becoming possible in inexpensive, compact, and robust devices. This opens up opportunities for new computational imaging techniques that make use of photon time of flight. Time of flight or range information is used in remote imaging scenarios in gated viewing and in biomedical imaging in time resolved diffuse tomography. In addition spatial filtering is popular in biomedical scenarios with structured illumination and confocal microscopy. We are presenting a combination analytical, computational, and experimental models that allow us develop and test imaging methods across scattering scenarios and scales. This framework will be used for proof of concept experiments to evaluate new computational imaging methods.

Terahertz Computed Tomography of NASA Thermal Protection System Materials

NASA Technical Reports Server (NTRS)

Roth, D. J.; Reyes-Rodriguez, S.; Zimdars, D. A.; Rauser, R. W.; Ussery, W. W.

2011-01-01

A terahertz axial computed tomography system has been developed that uses time domain measurements in order to form cross-sectional image slices and three-dimensional volume renderings of terahertz-transparent materials. The system can inspect samples as large as 0.0283 cubic meters (1 cubic foot) with no safety concerns as for x-ray computed tomography. In this study, the system is evaluated for its ability to detect and characterize flat bottom holes, drilled holes, and embedded voids in foam materials utilized as thermal protection on the external fuel tanks for the Space Shuttle. X-ray micro-computed tomography was also performed on the samples to compare against the terahertz computed tomography results and better define embedded voids. Limits of detectability based on depth and size for the samples used in this study are loosely defined. Image sharpness and morphology characterization ability for terahertz computed tomography are qualitatively described.

Radiochemistry, PET Imaging, and the Internet of Chemical Things

DOE PAGES

Thompson, Stephen; Kilbourn, Michael R.; Scott, Peter J. H.

2016-08-16

The Internet of Chemical Things (IoCT), a growing network of computers, mobile devices, online resources, software suites, laboratory equipment, synthesis apparatus, analytical devices, and a host of other machines, all interconnected to users, manufacturers, and others through the infrastructure of the Internet, is changing how we do chemistry. While in its infancy across many chemistry laboratories and departments, it became apparent when considering our own work synthesizing radiopharmaceuticals for positron emission tomography (PET) that a more mature incarnation of the IoCT already exists. Finally, how does the IoCT impact our lives today, and what does it hold for the smartmore » (radio)chemical laboratories of the future?« less

Radiochemistry, PET Imaging, and the Internet of Chemical Things

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

Thompson, Stephen; Kilbourn, Michael R.; Scott, Peter J. H.

The Internet of Chemical Things (IoCT), a growing network of computers, mobile devices, online resources, software suites, laboratory equipment, synthesis apparatus, analytical devices, and a host of other machines, all interconnected to users, manufacturers, and others through the infrastructure of the Internet, is changing how we do chemistry. While in its infancy across many chemistry laboratories and departments, it became apparent when considering our own work synthesizing radiopharmaceuticals for positron emission tomography (PET) that a more mature incarnation of the IoCT already exists. Finally, how does the IoCT impact our lives today, and what does it hold for the smartmore » (radio)chemical laboratories of the future?« less

Comparison of magnetic resonance imaging and computed tomography in suspected lesions in the posterior cranial fossa.

PubMed Central

Teasdale, G. M.; Hadley, D. M.; Lawrence, A.; Bone, I.; Burton, H.; Grant, R.; Condon, B.; Macpherson, P.; Rowan, J.

1989-01-01

OBJECTIVE--To compare computed tomography and magnetic resonance imaging in investigating patients suspected of having a lesion in the posterior cranial fossa. DESIGN--Randomised allocation of newly referred patients to undergo either computed tomography or magnetic resonance imaging; the alternative investigation was performed subsequently only in response to a request from the referring doctor. SETTING--A regional neuroscience centre serving 2.7 million. PATIENTS--1020 Patients recruited between April 1986 and December 1987, all suspected by neurologists, neurosurgeons, or other specialists of having a lesion in the posterior fossa and referred for neuroradiology. The groups allocated to undergo computed tomography or magnetic resonance imaging were well matched in distributions of age, sex, specialty of referring doctor, investigation as an inpatient or an outpatient, suspected site of lesion, and presumed disease process; the referring doctor's confidence in the initial clinical diagnosis was also similar. INTERVENTIONS--After the patients had been imaged by either computed tomography or magnetic resonance (using a resistive magnet of 0.15 T) doctors were given the radiologist's report and a form asking if they considered that imaging with the alternative technique was necessary and, if so, why; it also asked for their current diagnoses and their confidence in them. MAIN OUTCOME MEASURES--Number of requests for the alternative method of investigation. Assessment of characteristics of patients for whom further imaging was requested and lesions that were suspected initially and how the results of the second imaging affected clinicians' and radiologists' opinions. RESULTS--Ninety three of the 501 patients who initially underwent computed tomography were referred subsequently for magnetic resonance imaging whereas only 28 of the 493 patients who initially underwent magnetic resonance imaging were referred subsequently for computed tomography. Over the study the number of patients referred for magnetic resonance imaging after computed tomography increased but requests for computed tomography after magnetic resonance imaging decreased. The reason that clinicians gave most commonly for requesting further imaging by magnetic resonance was that the results of the initial computed tomography failed to exclude their suspected diagnosis (64 patients). This was less common in patients investigated initially by magnetic resonance imaging (eight patients). Management of 28 patients (6%) imaged initially with computed tomography and 12 patients (2%) imaged initially with magnetic resonance was changed on the basis of the results of the alternative imaging. CONCLUSIONS--Magnetic resonance imaging provided doctors with the information required to manage patients suspected of having a lesion in the posterior fossa more commonly than computed tomography, but computed tomography alone was satisfactory in 80% of cases... PMID:2506965

Congruence Between Pulmonary Function and Computed Tomography Imaging Assessment of Cystic Fibrosis Severity.

PubMed

Rybacka, Anna; Goździk-Spychalska, Joanna; Rybacki, Adam; Piorunek, Tomasz; Batura-Gabryel, Halina; Karmelita-Katulska, Katarzyna

2018-05-04

In cystic fibrosis, pulmonary function tests (PFTs) and computed tomography are used to assess lung function and structure, respectively. Although both techniques of assessment are congruent there are lingering doubts about which PFTs variables show the best congruence with computed tomography scoring. In this study we addressed the issue by reinvestigating the association between PFTs variables and the score of changes seen in computed tomography scans in patients with cystic fibrosis with and without pulmonary exacerbation. This retrospective study comprised 40 patients in whom PFTs and computed tomography were performed no longer than 3 weeks apart. Images (inspiratory: 0.625 mm slice thickness, 0.625 mm interval; expiratory: 1.250 mm slice thickness, 10 mm interval) were evaluated with the Bhalla scoring system. The most frequent structural abnormality found in scans were bronchiectases and peribronchial thickening. The strongest relationship was found between the Bhalla sore and forced expiratory volume in 1 s (FEV1). The Bhalla sore also was related to forced vital capacity (FVC), FEV1/FVC ratio, residual volume (RV), and RV/total lung capacity (TLC) ratio. We conclude that lung structural data obtained from the computed tomography examination are highly congruent to lung function data. Thus, computed tomography imaging may supersede functional assessment in cases of poor compliance with spirometry procedures in the lederly or children. Computed tomography also seems more sensitive than PFTs in the assessment of cystic fibrosis progression. Moreover, in early phases of cystic fibrosis, computed tomography, due to its excellent resolution, may be irreplaceable in monitoring pulmonary damage.

SCCT guidelines for the performance and acquisition of coronary computed tomographic angiography: A report of the society of Cardiovascular Computed Tomography Guidelines Committee: Endorsed by the North American Society for Cardiovascular Imaging (NASCI).

PubMed

Abbara, Suhny; Blanke, Philipp; Maroules, Christopher D; Cheezum, Michael; Choi, Andrew D; Han, B Kelly; Marwan, Mohamed; Naoum, Chris; Norgaard, Bjarne L; Rubinshtein, Ronen; Schoenhagen, Paul; Villines, Todd; Leipsic, Jonathon

In response to recent technological advancements in acquisition techniques as well as a growing body of evidence regarding the optimal performance of coronary computed tomography angiography (coronary CTA), the Society of Cardiovascular Computed Tomography Guidelines Committee has produced this update to its previously established 2009 "Guidelines for the Performance of Coronary CTA" (1). The purpose of this document is to provide standards meant to ensure reliable practice methods and quality outcomes based on the best available data in order to improve the diagnostic care of patients. Society of Cardiovascular Computed Tomography Guidelines for the Interpretation is published separately (2). The Society of Cardiovascular Computed Tomography Guidelines Committee ensures compliance with all existing standards for the declaration of conflict of interest by all authors and reviewers for the purpose ofclarity and transparency. Copyright © 2016 Society of Cardiovascular Computed Tomography. All rights reserved.

Image Fusion During Vascular and Nonvascular Image-Guided Procedures☆

PubMed Central

Abi-Jaoudeh, Nadine; Kobeiter, Hicham; Xu, Sheng; Wood, Bradford J.

2013-01-01

Image fusion may be useful in any procedure where previous imaging such as positron emission tomography, magnetic resonance imaging, or contrast-enhanced computed tomography (CT) defines information that is referenced to the procedural imaging, to the needle or catheter, or to an ultrasound transducer. Fusion of prior and intraoperative imaging provides real-time feedback on tumor location or margin, metabolic activity, device location, or vessel location. Multimodality image fusion in interventional radiology was initially introduced for biopsies and ablations, especially for lesions only seen on arterial phase CT, magnetic resonance imaging, or positron emission tomography/CT but has more recently been applied to other vascular and nonvascular procedures. Two different types of platforms are commonly used for image fusion and navigation: (1) electromagnetic tracking and (2) cone-beam CT. Both technologies would be reviewed as well as their strengths and weaknesses, indications, when to use one vs the other, tips and guidance to streamline use, and early evidence defining clinical benefits of these rapidly evolving, commercially available and emerging techniques. PMID:23993079

In vitro corrosion resistance of porous NiTi intervertebral fusion devices

NASA Astrophysics Data System (ADS)

Schrooten, Jan; Assad, Michel; Van Humbeeck, Jan; Leroux, Michel A.

2007-02-01

Porous titanium-nickel (PTN) intervertebral fusion devices, produced by self-propagating high-temperature synthesis, represent an alternative to traditional long-term implants in the orthopaedic field. PTN promotes tissue ingrowth and has succeeded short-term and long-term biocompatibility in vivo testing. In this in vitro study, the PTN morphology was characterized using microfocus computer tomography (μCT) in order to calculate the active PTN surface. Potentiodynamic polarization testing was then performed to evaluate the in vitro corrosion resistance of PTN devices in Hanks' based salt solution. Direct coupling experiments of PTN with Ti6Al4V were also performed in order to establish the galvanic corrosion resistance of PTN intervertebral implants in the presence of potential Ti6Al4V supplemental fixation devices. Compared to the behaviour of other orthopaedic biomaterials and solid NiTi devices, PTN devices showed a level of corrosion resistance that is comparable to other NiTi devices and acceptable for the intended orthopaedic application. Further improvement of the corrosion resistance is still possible by specific electrochemical surface treatments.

Application of multidetector-row computed tomography in propeller flap planning.

PubMed

Ono, Shimpei; Chung, Kevin C; Hayashi, Hiromitsu; Ogawa, Rei; Takami, Yoshihiro; Hyakusoku, Hiko

2011-02-01

The propeller flap is defined as (1) being island-shaped, (2) having an axis that includes the perforators, and (3) having the ability to be rotated around an axis. The advantage of the propeller flap is that it is a pedicle flap that can be applied to cover defects located at the distal ends of the extremities. The specific aims of the authors' study were (1) to evaluate the usefulness of multidetector-row computed tomography in the planning of propeller flaps and (2) to present a clinical case series of propeller flap reconstructions that were planned preoperatively using multidetector-row computed tomography. The authors retrospectively analyzed all cases between April of 2007 and April of 2010 at Nippon Medical School Hospital in Tokyo, where multidetector-row computed tomography was used preoperatively to plan surgical reconstructions using propeller flaps. Thirteen patients underwent 16 flaps using the propeller flap technique. The perforators were identified accurately by multidetector-row computed tomography preoperatively in all cases. This is the first report describing the application of multidetector-row computed tomography in the planning of propeller flaps. Multidetector-row computed tomography is superior to other imaging methods because it demonstrates more precisely the perforator's position and subcutaneous course using high-resolution three-dimensional images. By using multidetector-row computed tomography to preoperatively identify a flap's perforators, the surgeon can better plan the flap design to efficiently conduct the flap surgery.

Comparison of computed tomography and magnetic resonance imaging for the evaluation of canine intranasal neoplasia.

PubMed

Drees, R; Forrest, L J; Chappell, R

2009-07-01

Canine intranasal neoplasia is commonly evaluated using computed tomography to indicate the diagnosis, to determine disease extent, to guide histological sampling location and to plan treatment. With the expanding use of magnetic resonance imaging in veterinary medicine, this modality has been recently applied for the same purpose. The aim of this study was to compare the features of canine intranasal neoplasia using computed tomography and magnetic resonance imaging. Twenty-one dogs with confirmed intranasal neoplasia underwent both computed tomography and magnetic resonance imaging. The images were reviewed retrospectively for the bony and soft tissue features of intranasal neoplasia. Overall computed tomography and magnetic resonance imaging performed very similarly. However, lysis of bones bordering the nasal cavity and mucosal thickening was found on computed tomography images more often than on magnetic resonance images. Small amounts of fluid in the nasal cavity were more often seen on magnetic resonance images. However, fluid in the frontal sinuses was seen equally well with both modalities. We conclude that computed tomography is satisfactory for evaluation of canine intranasal neoplasia, and no clinically relevant benefit is gained using magnetic resonance imaging for intranasal neoplasia without extent into the cranial cavity.

3D Graphics For Interactive Surgical Simulation And Implant Design

NASA Astrophysics Data System (ADS)

Dev, P.; Fellingham, L. L.; Vassiliadis, A.; Woolson, S. T.; White, D. N.; Young, S. L.

1984-10-01

The combination of user-friendly, highly interactive software, 3D graphics, and the high-resolution detailed views of anatomy afforded by X-ray computer tomography and magnetic resonance imaging can provide surgeons with the ability to plan and practice complex surgeries. In addition to providing a realistic and manipulable 3D graphics display, this system can drive a milling machine in order to produce physical models of the anatomy or prosthetic devices and implants which have been designed using its interactive graphics editing facilities.

Photonic Breast Tomography and Tumor Aggressiveness Assessment

DTIC Science & Technology

2012-07-01

c) Raw Image 11 The entrance face of the slab sample (source plane) was illuminated by a 100-mW 790-nm diode laser beam. The multi-source...schematically shown in Figure 6. A 10mW 785 nm diode laser beam was used to illuminate the first sample, while a 100mW 785 nm diode laser beam was used for the...signal transmitting narrow-band filter; TS = translation stage; CCD = charge cou- pled device; and PC = computer. Continuous wave 790-nm diode laser

F-18-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Appearance of Extramedullary Hematopoesis in a Case of Primary Myelofibrosis

PubMed Central

Mukherjee, Anirban; Bal, Chandrasekhar; Tripathi, Madhavi; Das, Chandan Jyoti; Shamim, Shamim Ahmed

2017-01-01

A 44-year-old female with known primary myelofibrosis presented with shortness of breath. High Resolution Computed Tomography thorax revealed large heterogeneously enhancing extraparenchymal soft tissue density mass involving bilateral lung fields. F-18-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography revealed mildly FDG avid soft tissue density mass with specks of calcification involving bilateral lung fields, liver, and spleen. Subsequent histopathologic evaluation from the right lung mass was suggestive of extramedullary hematopoesis. PMID:28533647

Local setup errors in image-guided radiotherapy for head and neck cancer patients immobilized with a custom-made device.

PubMed

Giske, Kristina; Stoiber, Eva M; Schwarz, Michael; Stoll, Armin; Muenter, Marc W; Timke, Carmen; Roeder, Falk; Debus, Juergen; Huber, Peter E; Thieke, Christian; Bendl, Rolf

2011-06-01

To evaluate the local positioning uncertainties during fractionated radiotherapy of head-and-neck cancer patients immobilized using a custom-made fixation device and discuss the effect of possible patient correction strategies for these uncertainties. A total of 45 head-and-neck patients underwent regular control computed tomography scanning using an in-room computed tomography scanner. The local and global positioning variations of all patients were evaluated by applying a rigid registration algorithm. One bounding box around the complete target volume and nine local registration boxes containing relevant anatomic structures were introduced. The resulting uncertainties for a stereotactic setup and the deformations referenced to one anatomic local registration box were determined. Local deformations of the patients immobilized using our custom-made device were compared with previously published results. Several patient positioning correction strategies were simulated, and the residual local uncertainties were calculated. The patient anatomy in the stereotactic setup showed local systematic positioning deviations of 1-4 mm. The deformations referenced to a particular anatomic local registration box were similar to the reported deformations assessed from patients immobilized with commercially available Aquaplast masks. A global correction, including the rotational error compensation, decreased the remaining local translational errors. Depending on the chosen patient positioning strategy, the remaining local uncertainties varied considerably. Local deformations in head-and-neck patients occur even if an elaborate, custom-made patient fixation method is used. A rotational error correction decreased the required margins considerably. None of the considered correction strategies achieved perfect alignment. Therefore, weighting of anatomic subregions to obtain the optimal correction vector should be investigated in the future. Copyright © 2011 Elsevier Inc. All rights reserved.

Cone beam computed tomography in the diagnosis of dental disease.

PubMed

Tetradis, Sotirios; Anstey, Paul; Graff-Radford, Steven

2011-07-01

Conventional radiographs provide important information for dental disease diagnosis. However, they represent 2-D images of 3-D objects with significant structure superimposition and unpredictable magnification. Cone beam computed tomography, however, allows true 3-D visualization of the dentoalveolar structures, avoiding major limitations of conventional radiographs. Cone beam computed tomography images offer great advantages in disease detection for selected patients. The authors discuss cone beam computed tomography applications in dental disease diagnosis, reviewing the pertinent literature when available.

Multiscale tomographic analysis of heterogeneous cast Al-Si-X alloys.

PubMed

Asghar, Z; Requena, G; Sket, F

2015-07-01

The three-dimensional microstructure of cast AlSi12Ni and AlSi10Cu5Ni2 alloys is investigated by laboratory X-ray computed tomography, synchrotron X-ray computed microtomography, light optical tomography and synchrotron X-ray computed microtomography with submicrometre resolution. The results obtained with each technique are correlated with the size of the scanned volumes and resolved microstructural features. Laboratory X-ray computed tomography is sufficient to resolve highly absorbing aluminides but eutectic and primary Si remain unrevealed. Synchrotron X-ray computed microtomography at ID15/ESRF gives better spatial resolution and reveals primary Si in addition to aluminides. Synchrotron X-ray computed microtomography at ID19/ESRF reveals all the phases ≥ ∼1 μm in volumes about 80 times smaller than laboratory X-ray computed tomography. The volumes investigated by light optical tomography and submicrometre synchrotron X-ray computed microtomography are much smaller than laboratory X-ray computed tomography but both techniques provide local chemical information on the types of aluminides. The complementary techniques applied enable a full three-dimensional characterization of the microstructure of the alloys at length scales ranging over six orders of magnitude. © 2015 The Authors Journal of Microscopy © 2015 Royal Microscopical Society.

Electromagnetic Navigational Bronchoscopy Reduces the Time Required for Localization and Resection of Lung Nodules.

PubMed

Bolton, William David; Cochran, Thomas; Ben-Or, Sharon; Stephenson, James E; Ellis, William; Hale, Allyson L; Binks, Andrew P

The aims of the study were to evaluate electromagnetic navigational bronchoscopy (ENB) and computed tomography-guided placement as localization techniques for minimally invasive resection of small pulmonary nodules and determine whether electromagnetic navigational bronchoscopy is a safer and more effective method than computed tomography-guided localization. We performed a retrospective review of our thoracic surgery database to identify patients who underwent minimally invasive resection for a pulmonary mass and used either electromagnetic navigational bronchoscopy or computed tomography-guided localization techniques between July 2011 and May 2015. Three hundred eighty-three patients had a minimally invasive resection during our study period, 117 of whom underwent electromagnetic navigational bronchoscopy or computed tomography localization (electromagnetic navigational bronchoscopy = 81; computed tomography = 36). There was no significant difference between computed tomography and electromagnetic navigational bronchoscopy patient groups with regard to age, sex, race, pathology, nodule size, or location. Both computed tomography and electromagnetic navigational bronchoscopy were 100% successful at localizing the mass, and there was no difference in the type of definitive surgical resection (wedge, segmentectomy, or lobectomy) (P = 0.320). Postoperative complications occurred in 36% of all patients, but there were no complications related to the localization procedures. In terms of localization time and surgical time, there was no difference between groups. However, the down/wait time between localization and resection was significant (computed tomography = 189 minutes; electromagnetic navigational bronchoscopy = 27 minutes); this explains why the difference in total time (sum of localization, down, and surgery) was significant (P < 0.001). We found electromagnetic navigational bronchoscopy to be as safe and effective as computed tomography-guided wire placement and to provide a significantly decreased down time between localization and surgical resection.

MOEMS optical delay line for optical coherence tomography

NASA Astrophysics Data System (ADS)

Choudhary, Om P.; Chouksey, S.; Sen, P. K.; Sen, P.; Solanki, J.; Andrews, J. T.

2014-09-01

Micro-Opto-Electro-Mechanical optical coherence tomography, a lab-on-chip for biomedical applications is designed, studied, fabricated and characterized. To fabricate the device standard PolyMUMPS processes is adopted. We report the utilization of electro-optic modulator for a fast scanning optical delay line for time domain optical coherence tomography. Design optimization are performed using Tanner EDA while simulations are performed using COMSOL. The paper summarizes various results and fabrication methodology adopted. The success of the device promises a future hand-held or endoscopic optical coherence tomography for biomedical applications.

GAVeCeLT* consensus statement on the correct use of totally implantable venous access devices for diagnostic radiology procedures.

PubMed

Bonciarelli, Giorgio; Batacchi, Stefano; Biffi, Roberto; Buononato, Massimo; Damascelli, Bruno; Ghibaudo, Flavio; Orsi, Franco; Pittiruti, Mauro; Scoppettuolo, Giancarlo; Verzè, Alessia; Borasi, Guido; De Cicco, Marcello; Dosio, Roberto; Gazzo, Paolo; Maso, Renzo; Roman, Alessandro; Ticha, Vladimira; Venier, Giacomo; Blackburn, Paul; Goossens, Godelieve A; Bowen Santolucito, Jamie; Stas, Marguerite; Van Boxtel, Ton; Vesely, Thomas M; de Lutio, Enrico

2011-01-01

The use of totally implantable venous access devices in radiology may be associated with complications such as occlusion of the system (because of the high density of some contrast), infection (if the port is not handled in aseptic conditions, using proper barrier protections), and mechanical complications due to the high-pressure administration of contrast by automatic injectors (so-called power injector), including extravasation of contrast media into the soft tissues, subintimal venous or myocardial injection, or serious damage to the device itself (breakage of the external connections, dislocation of the non-coring needle, or breakage of the catheter). The last problem - i.e., the damage of the device from a power injection - is not an unjustified fear, but a reality. A warning by the US Food and Drug Administration of July 2004 reports around 250 complications of this kind, referring to both port and central venous catheters and peripherally inserted central catheter systems, which occurred over a period of several years; in all cases, the damage occurred during the injection of contrast material by means of power injectors for computed tomography or magnetic resonance imaging procedures. Though the risk associated with the use of ports in radiodiagnostics is thus clear, it has been suggested that administration of the contrast material via the port may have some advantage in terms of image quality, increased comfort for the patient, and maybe more accurate reproducibility of the patient's own follow-up exams. This contention needs to be supported by evidence. Also, since many cancer patients who need frequent computed tomography studies already have totally implantable systems, it would seem reasonable to try to define how and when such systems may safely be used. The purpose of this consensus statement is to define recommendations based on the best available evidence, for the safe use of implantable ports in radiodiagnostics.

A new device for improving dental implants anchorage: a histological and micro-computed tomography study in the rabbit.

PubMed

Barak, Shlomo; Neuman, Moshe; Iezzi, Giovanna; Piattelli, Adriano; Perrotti, Vittoria; Gabet, Yankel

2016-08-01

In the present study, a new healing cap that could generate a pulsed electromagnetic field (PEMF) around titanium implants to stimulate peri-implant osteogenesis was tested in the rabbit model. A total of 22 implants were inserted in the proximal tibial metaphysis of 22 rabbits. A healing cap containing the active device was inserted in half of the implants (11 test implants); an "empty" healing cap was inserted in the other ones (11 control implants). The animals were euthanized after 2 and 4 weeks, and the samples were processed for micro-computed tomography and histology. The peri-implant volume was divided into coronal (where the PEMF was the strongest) and apical regions. Most of the effects of the tested device were confined to the coronal region. Two weeks post-implantation, test implants showed a significant 56% higher trabecular bone fraction (BV/TV), associated with enhanced trabecular number (Tb.N, +37%) and connectivity density (Conn.D, +73%) as compared to the control group; at 4 weeks, the PEMF induced a 69% increase in BV/TV and 34% increase of Tb.N. There was no difference in the trabecular thickness (Tb.Th) at either time point. Furthermore, we observed a 48% higher bone-to-implant contact (BIC) in the test implants vs. controls after 2 weeks; this increase tended to remain stable until the fourth week. Mature trabecular and woven bone were observed in direct contact with the implant surface with no gaps or connective tissue at the bone-implant interface. These results indicate that the PEMF device stimulated early bone formation around dental implants resulting in higher peri-implant BIC and bone mass already after 2 weeks which suggests an acceleration of the osseointegration process by more than three times. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Sinonasal papilloma: what influences the decision to request a magnetic resonance imaging scan?

PubMed

Kasbekar, A V; Swords, C; Attlmayr, B; Kulkarni, T; Swift, A C

2018-06-18

Computed tomography is the standard pre-operative imaging modality for sinonasal papilloma. The complementary use of magnetic resonance imaging as an additional investigation is debated. This study aimed to establish whether magnetic resonance imaging can accurately detect tumour extent and is a useful adjunct to computed tomography. A retrospective review was conducted on 19 patients with sinonasal papilloma. The interpretation of computed tomography and magnetic resonance imaging scans, by three clinicians, was conducted by comparing prediction of tumour extent. The perceived necessity of magnetic resonance imaging was compared between clinicians. The addition of magnetic resonance imaging improved accuracy of pre-operative interpretation; specifically, this finding was significant in cases with frontal sinus involvement. Surgeons were more likely than a radiologist to request magnetic resonance imaging, particularly when computed tomography indicated frontal sinus disease. Pre-operative combined magnetic resonance imaging and computed tomography helped predict disease in the frontal sinus better than computed tomography alone. A close working relationship between the ENT and radiology departments is important for accurate tumour localisation.

Experimental Demonstration of Fault-Tolerant State Preparation with Superconducting Qubits.

PubMed

Takita, Maika; Cross, Andrew W; Córcoles, A D; Chow, Jerry M; Gambetta, Jay M

2017-11-03

Robust quantum computation requires encoding delicate quantum information into degrees of freedom that are hard for the environment to change. Quantum encodings have been demonstrated in many physical systems by observing and correcting storage errors, but applications require not just storing information; we must accurately compute even with faulty operations. The theory of fault-tolerant quantum computing illuminates a way forward by providing a foundation and collection of techniques for limiting the spread of errors. Here we implement one of the smallest quantum codes in a five-qubit superconducting transmon device and demonstrate fault-tolerant state preparation. We characterize the resulting code words through quantum process tomography and study the free evolution of the logical observables. Our results are consistent with fault-tolerant state preparation in a protected qubit subspace.

Assessing carotid atherosclerosis by fiber-optic multispectral photoacoustic tomography

NASA Astrophysics Data System (ADS)

Hui, Jie; Li, Rui; Wang, Pu; Phillips, Evan; Bruning, Rebecca; Liao, Chien-Sheng; Sturek, Michael; Goergen, Craig J.; Cheng, Ji-Xin

2015-03-01

Atherosclerotic plaque at the carotid bifurcation is the underlying cause of the majority of ischemic strokes. Noninvasive imaging and quantification of the compositional changes preceding gross anatomic changes within the arterial wall is essential for diagnosis of disease. Current imaging modalities such as duplex ultrasound, computed tomography, positron emission tomography are limited by the lack of compositional contrast and the detection of flow-limiting lesions. Although high-resolution magnetic resonance imaging has been developed to characterize atherosclerotic plaque composition, its accessibility for wide clinical use is limited. Here, we demonstrate a fiber-based multispectral photoacoustic tomography system for excitation of lipids and external acoustic detection of the generated ultrasound. Using sequential ultrasound imaging of ex vivo preparations we achieved ~2 cm imaging depth and chemical selectivity for assessment of human arterial plaques. A multivariate curve resolution alternating least squares analysis method was applied to resolve the major chemical components, including intravascular lipid, intramuscular fat, and blood. These results show the promise of detecting carotid plaque in vivo through esophageal fiber-optic excitation of lipids and external acoustic detection of the generated ultrasound. This imaging system has great potential for serving as a point-ofcare device for early diagnosis of carotid artery disease in the clinic.

Computer tomography of the neurocranium.

PubMed

Liliequist, B; Forssell, A

1976-07-01

The experience with computer tomography of the neurocranium in 300 patients submitted for computer tomography of the brain is reported. The more appropriate projections which may be obtained with the second generation of scanners in combination with an elaborated reconstruction technique seem to constitute a replacement of conventional skull films.

The use of imaging for electrophysiological and devices procedures: a report from the first European Heart Rhythm Association Policy Conference, jointly organized with the European Association of Cardiovascular Imaging (EACVI), the Council of Cardiovascular Imaging and the European Society of Cardiac Radiology.

PubMed

Blomström Lundqvist, Carina; Auricchio, Angelo; Brugada, Josep; Boriani, Giuseppe; Bremerich, Jens; Cabrera, Jose Angel; Frank, Herbert; Gutberlet, Matthias; Heidbuchel, Hein; Kuck, Karl-Heinz; Lancellotti, Patrizio; Rademakers, Frank; Winkels, Gerard; Wolpert, Christian; Vardas, Panos E

2013-07-01

Implantations of cardiac devices therapies and ablation procedures frequently depend on accurate and reliable imaging modalities for pre-procedural assessments, intra-procedural guidance, detection of complications, and the follow-up of patients. An understanding of echocardiography, cardiovascular magnetic resonance imaging, nuclear cardiology, X-ray computed tomography, positron emission tomography, and vascular ultrasound is indispensable for cardiologists, electrophysiologists as well as radiologists, and it is currently recommended that physicians should be trained in several imaging modalities. There are, however, no current guidelines or recommendations by electrophysiologists, cardiac imaging specialists, and radiologists, on the appropriate use of cardiovascular imaging for selected patient indications, which needs to be addressed. A Policy Conference on the use of imaging in electrophysiology and device management, with representatives from different expert areas of radiology and electrophysiology and commercial developers of imaging and device technologies, was therefore jointly organized by European Heart Rhythm Association (EHRA), the Council of Cardiovascular Imaging and the European Society of Cardiac Radiology (ESCR). The objectives were to assess the state of the level of evidence and a first step towards a consensus document for currently employed imaging techniques to guide future clinical use, to elucidate the issue of reimbursement structures and health economy, and finally to define the need for appropriate educational programmes to ensure clinical competence for electrophysiologists, imaging specialists, and radiologists.

Laser interference fringe tomography: a novel 3D imaging technique for pathology

NASA Astrophysics Data System (ADS)

Kazemzadeh, Farnoud; Haylock, Thomas M.; Chifman, Lev M.; Hajian, Arsen R.; Behr, Bradford B.; Cenko, Andrew T.; Meade, Jeff T.; Hendrikse, Jan

2011-03-01

Laser interference fringe tomography (LIFT) is within the class of optical imaging devices designed for in vivo and ex vivo medical imaging applications. LIFT is a very simple and cost-effective three-dimensional imaging device with performance rivaling some of the leading three-dimensional imaging devices used for histology. Like optical coherence tomography (OCT), it measures the reflectivity as a function of depth within a sample and is capable of producing three-dimensional images from optically scattering media. LIFT has the potential capability to produce high spectral resolution, full-color images. The optical design of LIFT along with the planned iterations for improvements and miniaturization are presented and discussed in addition to the theoretical concepts and preliminary imaging results of the device.

The holographic display of three-dimensional medical objects through the usage of a shiftable cylindrical lens

NASA Astrophysics Data System (ADS)

Teng, Dongdong; Liu, Lilin; Zhang, Yueli; Pang, Zhiyong; Wang, Biao

2014-09-01

Through the creative usage of a shiftable cylindrical lens, a wide-view-angle holographic display system is developed for medical object display in real three-dimensional (3D) space based on a time-multiplexing method. The two-dimensional (2D) source images for all computer generated holograms (CGHs) needed by the display system are only one group of computerized tomography (CT) or magnetic resonance imaging (MRI) slices from the scanning device. Complicated 3D message reconstruction on the computer is not necessary. A pelvis is taken as the target medical object to demonstrate this method and the obtained horizontal viewing angle reaches 28°.

MRI-powered biomedical devices.

PubMed

Hovet, Sierra; Ren, Hongliang; Xu, Sheng; Wood, Bradford; Tokuda, Junichi; Tse, Zion Tsz Ho

2017-11-16

Magnetic resonance imaging (MRI) is beneficial for imaging-guided procedures because it provides higher resolution images and better soft tissue contrast than computed tomography (CT), ultrasound, and X-ray. MRI can be used to streamline diagnostics and treatment because it does not require patients to be repositioned between scans of different areas of the body. It is even possible to use MRI to visualize, power, and control medical devices inside the human body to access remote locations and perform minimally invasive procedures. Therefore, MR conditional medical devices have the potential to improve a wide variety of medical procedures; this potential is explored in terms of practical considerations pertaining to clinical applications and the MRI environment. Recent advancements in this field are introduced with a review of clinically relevant research in the areas of interventional tools, endovascular microbots, and closed-loop controlled MRI robots. Challenges related to technology and clinical feasibility are discussed, including MRI based propulsion and control, navigation of medical devices through the human body, clinical adoptability, and regulatory issues. The development of MRI-powered medical devices is an emerging field, but the potential clinical impact of these devices is promising.

Spectroscopic micro-tomography of metallic-organic composites by means of photon-counting detectors

NASA Astrophysics Data System (ADS)

Pichotka, M.; Jakubek, J.; Vavrik, D.

2015-12-01

The presumed capabilities of photon counting detectors have aroused major expectations in several fields of research. In the field of nuclear imaging ample benefits over standard detectors are to be expected from photon counting devices. First of all a very high contrast, as has by now been verified in numerous experiments. The spectroscopic capabilities of photon counting detectors further allow material decomposition in computed tomography and therefore inherently adequate beam hardening correction. For these reasons measurement setups featuring standard X-ray tubes combined with photon counting detectors constitute a possible replacement of the much more cost intensive tomographic setups at synchrotron light-sources. The actual application of photon counting detectors in radiographic setups in recent years has been impeded by a number of practical issues, above all by restrictions in the detectors size. Currently two tomographic setups in Czech Republic feature photon counting large-area detectors (LAD) fabricated in Prague. The employed large area hybrid pixel-detector assemblies [1] consisting of 10×10/10×5 Timepix devices have a surface area of 143×143 mm2 / 143×71,5 mm2 respectively, suitable for micro-tomographic applications. In the near future LAD devices featuring the Medipix3 readout chip as well as heavy sensors (CdTe, GaAs) will become available. Data analysis is obtained by a number of in house software tools including iterative multi-energy volume reconstruction.In this paper tomographic analysis of of metallic-organic composites is employed to illustrate the capabilities of our technology. Other than successful material decomposition by spectroscopic tomography we present a method to suppress metal artefacts under certain conditions.

Monte Carlo simulations in multi-detector CT (MDCT) for two PET/CT scanner models using MASH and FASH adult phantoms

NASA Astrophysics Data System (ADS)

Belinato, W.; Santos, W. S.; Paschoal, C. M. M.; Souza, D. N.

2015-06-01

The combination of positron emission tomography (PET) and computed tomography (CT) has been extensively used in oncology for diagnosis and staging of tumors, radiotherapy planning and follow-up of patients with cancer, as well as in cardiology and neurology. This study determines by the Monte Carlo method the internal organ dose deposition for computational phantoms created by multidetector CT (MDCT) beams of two PET/CT devices operating with different parameters. The different MDCT beam parameters were largely related to the total filtration that provides a beam energetic change inside the gantry. This parameter was determined experimentally with the Accu-Gold Radcal measurement system. The experimental values of the total filtration were included in the simulations of two MCNPX code scenarios. The absorbed organ doses obtained in MASH and FASH phantoms indicate that bowtie filter geometry and the energy of the X-ray beam have significant influence on the results, although this influence can be compensated by adjusting other variables such as the tube current-time product (mAs) and pitch during PET/CT procedures.

Morphometric analysis - Cone beam computed tomography to predict bone quality and quantity.

PubMed

Hohlweg-Majert, B; Metzger, M C; Kummer, T; Schulze, D

2011-07-01

Modified quantitative computed tomography is a method used to predict bone quality and quantify the bone mass of the jaw. The aim of this study was to determine whether bone quantity or quality was detected by cone beam computed tomography (CBCT) combined with image analysis. MATERIALS AND PROCEDURES: Different measurements recorded on two phantoms (Siemens phantom, Comac phantom) were evaluated on images taken with the Somatom VolumeZoom (Siemens Medical Solutions, Erlangen, Germany) and the NewTom 9000 (NIM s.r.l., Verona, Italy) in order to calculate a calibration curve. The spatial relationships of six sample cylinders and the repositioning from four pig skull halves relative to adjacent defined anatomical structures were assessed by means of three-dimensional visualization software. The calibration curves for computer tomography (CT) and cone beam computer tomography (CBCT) using the Siemens phantom showed linear correlation in both modalities between the Hounsfield Units (HU) and bone morphology. A correction factor for CBCT was calculated. Exact information about the micromorphology of the bone cylinders was only available using of micro computer tomography. Cone-beam computer tomography is a suitable choice for analysing bone mass, but, it does not give any information about bone quality. 2010 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Italian Chapter of the International Society of Cardiovascular Ultrasound expert consensus document on coronary computed tomography angiography: overview and new insights.

PubMed

Sozzi, Fabiola B; Maiello, Maria; Pelliccia, Francesco; Parato, Vito Maurizio; Canetta, Ciro; Savino, Ketty; Lombardi, Federico; Palmiero, Pasquale

2016-09-01

Coronary computed tomography angiography is a noninvasive heart imaging test currently undergoing rapid development and advancement. The high resolution of the three-dimensional pictures of the moving heart and great vessels is performed during a coronary computed tomography to identify coronary artery disease and classify patient risk for atherosclerotic cardiovascular disease. The technique provides useful information about the coronary tree and atherosclerotic plaques beyond simple luminal narrowing and plaque type defined by calcium content. This application will improve image-guided prevention, medical therapy, and coronary interventions. The ability to interpret coronary computed tomography images is of utmost importance as we develop personalized medical care to enable therapeutic interventions stratified on the bases of plaque characteristics. This overview provides available data and expert's recommendations in the utilization of coronary computed tomography findings. We focus on the use of coronary computed tomography to detect coronary artery disease and stratify patients at risk, illustrating the implications of this test on patient management. We describe its diagnostic power in identifying patients at higher risk to develop acute coronary syndrome and its prognostic significance. Finally, we highlight the features of the vulnerable plaques imaged by coronary computed tomography angiography. © 2016, Wiley Periodicals, Inc.

Comparison of computed tomography and magnetic resonance imaging for the evaluation of canine intranasal neoplasia

PubMed Central

Drees, R.; Forrest, L. J.; Chappell, R.

2009-01-01

Objectives Canine intranasal neoplasia is commonly evaluated using computed tomography to indicate the diagnosis, to determine disease extent, to guide histological sampling location and to plan treatment. With the expanding use of magnetic resonance imaging in veterinary medicine, this modality has been recently applied for the same purpose. The aim of this study was to compare the features of canine intranasal neoplasia using computed tomography and magnetic resonance imaging. Methods Twenty-one dogs with confirmed intranasal neoplasia underwent both computed tomography and magnetic resonance imaging. The images were reviewed retrospectively for the bony and soft tissue features of intranasal neoplasia. Results Overall computed tomography and magnetic resonance imaging performed very similarly. However, lysis of bones bordering the nasal cavity and mucosal thickening was found on computed tomography images more often than on magnetic resonance images. Small amounts of fluid in the nasal cavity were more often seen on magnetic resonance images. However, fluid in the frontal sinuses was seen equally well with both modalities. Clinical Significance We conclude that computed tomography is satisfactory for evaluation of canine intranasal neoplasia, and no clinically relevant benefit is gained using magnetic resonance imaging for intranasal neoplasia without extent into the cranial cavity. PMID:19508490

Investigation of biomechanical behavior of lumbar vertebral segments with dynamic stabilization device using finite element approach

NASA Astrophysics Data System (ADS)

Deoghare, Ashish B.; Kashyap, Siddharth; Padole, Pramod M.

2013-03-01

Degenerative disc disease is a major source of lower back pain and significantly alters the biomechanics of the lumbar spine. Dynamic stabilization device is a remedial technique which uses flexible materials to stabilize the affected lumbar region while preserving the natural anatomy of the spine. The main objective of this research work is to investigate the stiffness variation of dynamic stabilization device under various loading conditions under compression, axial rotation and flexion. Three dimensional model of the two segment lumbar spine is developed using computed tomography (CT) scan images. The lumbar structure developed is analyzed in ANSYS workbench. Two types of dynamic stabilization are considered: one with stabilizing device as pedicle instrumentation and second with stabilization device inserted around the inter-vertebral disc. Analysis suggests that proper positioning of the dynamic stabilization device is of paramount significance prior to the surgery. Inserting the device in the posterior region indicates the adverse effects as it shows increase in the deformation of the inter-vertebral disc. Analysis executed by positioning stabilizing device around the inter-vertebral disc yields better result for various stiffness values under compression and other loadings. [Figure not available: see fulltext.

Measurement of Three-dimensional Density Distributions by Holographic Interferometry and Computer Tomography

NASA Technical Reports Server (NTRS)

Vest, C. M.

1982-01-01

The use of holographic interferometry to measure two and threedimensional flows and the interpretation of multiple-view interferograms with computer tomography are discussed. Computational techniques developed for tomography are reviewed. Current research topics are outlined including the development of an automated fringe readout system, optimum reconstruction procedures for when an opaque test model is present in the field, and interferometry and tomography with strongly refracting fields and shocks.

Evaluation and clinical use of an intraoral inferior alveolar nerve block in the horse.

PubMed

Henry, T; Pusterla, N; Guedes, A G P; Verstraete, F J M

2014-11-01

Local anaesthesia is often required to facilitate invasive procedures in equine dental patients under standing sedation. To show that an intraoral approach can be used to desensitise the inferior alveolar nerve in horses and report complications seen with this technique. The distance of the mandibular foramen from the distal (caudal) edge of the mandibular third molar tooth, rostral edge of the mandibular ramus and ventral margin of the mandible were measured in 26 adult equine skulls of various ages and breeds. Computed tomography (CT) was used to verify the placement of the local anaesthetic with a custom-made device on 4 equine cadaver heads. The technique was applied in 43 clinical cases having procedures performed on the mandibular quadrants using the delivery device. Computed tomography demonstrated that the intraoral approach provided deposition of the local anaesthetic at the mandibular foramen and anatomical localisation of mandibular foramen indicated that anaesthetic solution could be delivered with a 38 mm needle. Clinical patients to lerated invasive dental procedures following the inferior alveolar nerve block with a 5 ml dose of local anaesthetic, without evidence of self-inflicted lingual trauma. The inferior alveolar nerve was successfully desensitised with the intraoral approach with minimal complications. The reduced volume of local anaesthetic and ability to deposit the local anaesthetic in close proximity to the nerve compared with an extraoral technique may decrease the complication of self-inflicted lingual trauma. © 2013 EVJ Ltd.

Advantages and Disadvantages in Image Processing with Free Software in Radiology.

PubMed

Mujika, Katrin Muradas; Méndez, Juan Antonio Juanes; de Miguel, Andrés Framiñan

2018-01-15

Currently, there are sophisticated applications that make it possible to visualize medical images and even to manipulate them. These software applications are of great interest, both from a teaching and a radiological perspective. In addition, some of these applications are known as Free Open Source Software because they are free and the source code is freely available, and therefore it can be easily obtained even on personal computers. Two examples of free open source software are Osirix Lite® and 3D Slicer®. However, this last group of free applications have limitations in its use. For the radiological field, manipulating and post-processing images is increasingly important. Consequently, sophisticated computing tools that combine software and hardware to process medical images are needed. In radiology, graphic workstations allow their users to process, review, analyse, communicate and exchange multidimensional digital images acquired with different image-capturing radiological devices. These radiological devices are basically CT (Computerised Tomography), MRI (Magnetic Resonance Imaging), PET (Positron Emission Tomography), etc. Nevertheless, the programs included in these workstations have a high cost which always depends on the software provider and is always subject to its norms and requirements. With this study, we aim to present the advantages and disadvantages of these radiological image visualization systems in the advanced management of radiological studies. We will compare the features of the VITREA2® and AW VolumeShare 5® radiology workstation with free open source software applications like OsiriX® and 3D Slicer®, with examples from specific studies.

Successful treatment of growing basilar artery dissecting aneurysm by pipeline flow diversion embolization device.

PubMed

Gong, Dasen; Yan, Bernard; Dowling, Richard; Mitchell, Peter

2014-07-01

We describe a case of successful management of a growing basilar artery dissecting aneurysm by the Pipeline flow diversion embolization device (PED). A 48-year-old woman presented with severe headache, neck pain, and altered consciousness. Computed tomography showed subarachnoid hemorrhage located in basal cisterns, with a pontine infarct shown on magnetic resonance imaging. Digital subtraction angiography showed dissecting aneurysm of the trunk of the basilar artery, with growth over time on repeated imaging. Repeated imaging demonstrated growth in size of the aneurysm. The aneurysm was treated with PED with complete obliteration of the basilar artery aneurysm. Subsequent follow-up demonstrated good clinical recovery. Copyright © 2014 National Stroke Association. Published by Elsevier Inc. All rights reserved.

Improving early diagnosis of pulmonary infections in patients with febrile neutropenia using low-dose chest computed tomography.

PubMed

Gerritsen, M G; Willemink, M J; Pompe, E; van der Bruggen, T; van Rhenen, A; Lammers, J W J; Wessels, F; Sprengers, R W; de Jong, P A; Minnema, M C

2017-01-01

We performed a prospective study in patients with chemotherapy induced febrile neutropenia to investigate the diagnostic value of low-dose computed tomography compared to standard chest radiography. The aim was to compare both modalities for detection of pulmonary infections and to explore performance of low-dose computed tomography for early detection of invasive fungal disease. The low-dose computed tomography remained blinded during the study. A consensus diagnosis of the fever episode made by an expert panel was used as reference standard. We included 67 consecutive patients on the first day of febrile neutropenia. According to the consensus diagnosis 11 patients (16.4%) had pulmonary infections. Sensitivity, specificity, positive predictive value and negative predictive value were 36%, 93%, 50% and 88% for radiography, and 73%, 91%, 62% and 94% for low-dose computed tomography, respectively. An uncorrected McNemar showed no statistical difference (p = 0.197). Mean radiation dose for low-dose computed tomography was 0.24 mSv. Four out of 5 included patients diagnosed with invasive fungal disease had radiographic abnormalities suspect for invasive fungal disease on the low-dose computed tomography scan made on day 1 of fever, compared to none of the chest radiographs. We conclude that chest radiography has little value in the initial assessment of febrile neutropenia on day 1 for detection of pulmonary abnormalities. Low-dose computed tomography improves detection of pulmonary infiltrates and seems capable of detecting invasive fungal disease at a very early stage with a low radiation dose.

Improving early diagnosis of pulmonary infections in patients with febrile neutropenia using low-dose chest computed tomography

PubMed Central

Pompe, E.; van der Bruggen, T.; van Rhenen, A.; Lammers, J. W. J.; Wessels, F.; Sprengers, R. W.; de Jong, P. A.; Minnema, M. C.

2017-01-01

We performed a prospective study in patients with chemotherapy induced febrile neutropenia to investigate the diagnostic value of low-dose computed tomography compared to standard chest radiography. The aim was to compare both modalities for detection of pulmonary infections and to explore performance of low-dose computed tomography for early detection of invasive fungal disease. The low-dose computed tomography remained blinded during the study. A consensus diagnosis of the fever episode made by an expert panel was used as reference standard. We included 67 consecutive patients on the first day of febrile neutropenia. According to the consensus diagnosis 11 patients (16.4%) had pulmonary infections. Sensitivity, specificity, positive predictive value and negative predictive value were 36%, 93%, 50% and 88% for radiography, and 73%, 91%, 62% and 94% for low-dose computed tomography, respectively. An uncorrected McNemar showed no statistical difference (p = 0.197). Mean radiation dose for low-dose computed tomography was 0.24 mSv. Four out of 5 included patients diagnosed with invasive fungal disease had radiographic abnormalities suspect for invasive fungal disease on the low-dose computed tomography scan made on day 1 of fever, compared to none of the chest radiographs. We conclude that chest radiography has little value in the initial assessment of febrile neutropenia on day 1 for detection of pulmonary abnormalities. Low-dose computed tomography improves detection of pulmonary infiltrates and seems capable of detecting invasive fungal disease at a very early stage with a low radiation dose. PMID:28235014

Evaluating Device Design and Cleanability of Orthopedic Device Models Contaminated with a Clinically Relevant Bone Test Soil.

PubMed

Lucas, Anne D; Nagaraja, Srinidhi; Gordon, Edward A; Hitchins, Victoria M

2015-01-01

Reusable medical devices need to be cleaned prior to disinfection or sterilization and subsequent use to prevent infections. The cleanability of medical devices depends in part on the design of the device. This study examined how models of orthopedic medical devices of increasing complexity retain calcium phosphate bone cement, a relevant test soil for these devices. The dye Alizarin Red S and micro-computed tomography (μCT) were used to assess the amount and location of bone cement debris in a series of model orthopedic devices. Testing was performed after soiling and cleaning once, and soiling and cleaning 10 times. The color change of the dye after reacting with the bone cement was useful for indicating the presence of bone cement in these models. High-resolution μCT analysis provided the volume and location of the bone cement. Models that were more complex retained significantly more bone debris than simpler designs. Model devices repeatedly soiled and cleaned 10 times retained significantly more bone debris than those soiled and cleaned once. Significantly more bone cement was retained in the more complex lumen structures. This information may be useful in designing reusable orthopedic devices, and other complex medical devices with lumens.

X-ray tomography system to investigate granular materials during mechanical loading

NASA Astrophysics Data System (ADS)

Athanassiadis, Athanasios G.; La Rivière, Patrick J.; Sidky, Emil; Pelizzari, Charles; Pan, Xiaochuan; Jaeger, Heinrich M.

2014-08-01

We integrate a small and portable medical x-ray device with mechanical testing equipment to enable in situ, non-invasive measurements of a granular material's response to mechanical loading. We employ an orthopedic C-arm as the x-ray source and detector to image samples mounted in the materials tester. We discuss the design of a custom rotation stage, which allows for sample rotation and tomographic reconstruction under applied compressive stress. We then discuss the calibration of the system for 3D computed tomography, as well as the subsequent image reconstruction process. Using this system to reconstruct packings of 3D-printed particles, we resolve packing features with 0.52 mm resolution in a (60 mm)3 field of view. By analyzing the performance bounds of the system, we demonstrate that the reconstructions exhibit only moderate noise.

Multimodality Image Fusion-Guided Procedures: Technique, Accuracy, and Applications

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

Abi-Jaoudeh, Nadine, E-mail: naj@mail.nih.gov; Kruecker, Jochen, E-mail: jochen.kruecker@philips.com; Kadoury, Samuel, E-mail: samuel.kadoury@polymtl.ca

2012-10-15

Personalized therapies play an increasingly critical role in cancer care: Image guidance with multimodality image fusion facilitates the targeting of specific tissue for tissue characterization and plays a role in drug discovery and optimization of tailored therapies. Positron-emission tomography (PET), magnetic resonance imaging (MRI), and contrast-enhanced computed tomography (CT) may offer additional information not otherwise available to the operator during minimally invasive image-guided procedures, such as biopsy and ablation. With use of multimodality image fusion for image-guided interventions, navigation with advanced modalities does not require the physical presence of the PET, MRI, or CT imaging system. Several commercially available methodsmore » of image-fusion and device navigation are reviewed along with an explanation of common tracking hardware and software. An overview of current clinical applications for multimodality navigation is provided.« less

Flow visualization V; Proceedings of the 5th International Symposium, Prague, Czechoslovakia, Aug. 21-25, 1989

NASA Astrophysics Data System (ADS)

Reznicek, R.

The present conference on flow visualization encompasses methods exploiting tracing particles, surface tracing methods, methods exploiting the effects of streaming fluid on passing radiation/field, computer-aided flow visualization, and applications to fluid mechanics, aerodynamics, flow devices, shock tubes, and heat/mass transfer. Specific issues include visualizing velocity distribution by stereo photography, dark-field Fourier quasiinterferometry, speckle tomography of an open flame, a fast eye for real-time image analysis, and velocity-field determination based on flow-image analysis. Also addressed are flows around rectangular prisms with oscillating flaps at the leading edges, the tomography of aerodynamic objects, the vapor-screen technique applied to a delta-wing aircraft, flash-lamp planar imaging, IR-thermography applications in convective heat transfer, and the visualization of marangoni effects in evaporating sessile drops.

[Comparative assessment of MR-semiotics of acutest intracerebral hematomas in low- and extra high-field frequency magnetic resonance tomography].

PubMed

Skvortsova, V I; Burenchev, D V; Tvorogova, T V; Guseva, O I; Prokhorov, A V; Smirnov, A M; Kupriianov, D A; Pirogov, Iu A

2009-01-01

An objective of the study was to compare sensitivity of low- and extra high-field frequency magnetic resonance (MR) tomography of acutest intracerebral hematomas (ICH) and to assess differences between symptoms in obtained images. A study was conducted using experimental ICH in rats (n=6). Hematomas were formed by two injections of autologic blood into the brain. MR-devices "Bio Spec 70/30" with magnetic field strength of 7 T and "Ellipse-150" with magnetic field strength of 0,15 T were used in the study. MR-tomography was carried out 3-5 h after the injections. Both MR-devices revealed the presence of pathological lesion in all animals. Extra highfield frequency MR-tomography showed the specific signs of ICH caused by the paramagnetic effect of deoxyhemoglobin in T2 and T2*-weighted images (WI) and low frequency MR-tomography - in T2*-WI only. The comparable sensitivity of low- and extra high-field frequency MR-devices in acutest ICH was established.

Cone beam x-ray luminescence computed tomography reconstruction with a priori anatomical information

NASA Astrophysics Data System (ADS)

Lo, Pei-An; Lin, Meng-Lung; Jin, Shih-Chun; Chen, Jyh-Cheng; Lin, Syue-Liang; Chang, C. Allen; Chiang, Huihua Kenny

2014-09-01

X-ray luminescence computed tomography (XLCT) is a novel molecular imaging modality that reconstructs the optical distribution of x-ray-excited phosphor particles with prior informational of anatomical CT image. The prior information improves the accuracy of image reconstruction. The system can also present anatomical CT image. The optical system based on a high sensitive charge coupled device (CCD) is perpendicular with a CT system. In the XLCT system, the xray was adopted to excite the phosphor of the sample and CCD camera was utilized to acquire luminescence emitted from the sample in 360 degrees projection free-space. In this study, the fluorescence diffuse optical tomography (FDOT)-like algorithm was used for image reconstruction, the structural prior information was incorporated in the reconstruction by adding a penalty term to the minimization function. The phosphor used in this study is Gd2O2S:Tb. For the simulation and experiments, the data was collected from 16 projections. The cylinder phantom was 40 mm in diameter and contains 8 mm diameter inclusion; the phosphor in the in vivo study was 5 mm in diameter at a depth of 3 mm. Both the errors were no more than 5%. Based on the results from these simulation and experimental studies, the novel XLCT method has demonstrated the feasibility for in vivo animal model studies.

A noble technique a using force-sensing resistor for immobilization-device quality assurance: A feasibility study

NASA Astrophysics Data System (ADS)

Cho, Min-Seok; Kim, Tae-Ho; Kang, Seong-Hee; Kim, Dong-Su; Kim, Kyeong-Hyeon; Shin, Dong-Seok; Noh, Yu-Yun; Koo, Hyun-Jae; Cheon, Geum Seong; Suh, Tae Suk; Kim, Siyong

2016-03-01

Many studies have reported that a patient can move even when an immobilization device is used. Researchers have developed an immobilization-device quality-assurance (QA) system that evaluates the validity of immobilization devices. The QA system consists of force-sensing-resistor (FSR) sensor units, an electric circuit, a signal conditioning device, and a control personal computer (PC) with in-house software. The QA system is designed to measure the force between an immobilization device and a patient's skin by using the FSR sensor unit. This preliminary study aimed to evaluate the feasibility of using the QA system in radiation-exposure situations. When the FSR sensor unit was irradiated with a computed tomography (CT) beam and a treatment beam from a linear accelerator (LINAC), the stability of the output signal, the image artifact on the CT image, and changing the variation on the patient's dose were tested. The results of this study demonstrate that this system is promising in that it performed within the error range (signal variation on CT beam < 0.30 kPa, root-mean-square error (RMSE) of the two CT images according to presence or absence of the FSR sensor unit < 15 HU, signal variation on the treatment beam < 0.15 kPa, and dose difference between the presence and the absence of the FSR sensor unit < 0.02%). Based on the obtained results, we will volunteer tests to investigate the clinical feasibility of the QA system.

Analyzing Dental Implant Sites From Cone Beam Computed Tomography Scans on a Tablet Computer: A Comparative Study Between iPad and 3 Display Systems.

PubMed

Carrasco, Alejandro; Jalali, Elnaz; Dhingra, Ajay; Lurie, Alan; Yadav, Sumit; Tadinada, Aditya

2017-06-01

The aim of this study was to compare a medical-grade PACS (picture archiving and communication system) monitor, a consumer-grade monitor, a laptop computer, and a tablet computer for linear measurements of height and width for specific implant sites in the posterior maxilla and mandible, along with visualization of the associated anatomical structures. Cone beam computed tomography (CBCT) scans were evaluated. The images were reviewed using PACS-LCD monitor, consumer-grade LCD monitor using CB-Works software, a 13″ MacBook Pro, and an iPad 4 using OsiriX DICOM reader software. The operators had to identify anatomical structures in each display using a 2-point scale. User experience between PACS and iPad was also evaluated by means of a questionnaire. The measurements were very similar for each device. P-values were all greater than 0.05, indicating no significant difference between the monitors for each measurement. The intraoperator reliability was very high. The user experience was similar in each category with the most significant difference regarding the portability where the PACS display received the lowest score and the iPad received the highest score. The iPad with retina display was comparable with the medical-grade monitor, producing similar measurements and image visualization, and thus providing an inexpensive, portable, and reliable screen to analyze CBCT images in the operating room during the implant surgery.

GPU-based cone beam computed tomography.

PubMed

Noël, Peter B; Walczak, Alan M; Xu, Jinhui; Corso, Jason J; Hoffmann, Kenneth R; Schafer, Sebastian

2010-06-01

The use of cone beam computed tomography (CBCT) is growing in the clinical arena due to its ability to provide 3D information during interventions, its high diagnostic quality (sub-millimeter resolution), and its short scanning times (60 s). In many situations, the short scanning time of CBCT is followed by a time-consuming 3D reconstruction. The standard reconstruction algorithm for CBCT data is the filtered backprojection, which for a volume of size 256(3) takes up to 25 min on a standard system. Recent developments in the area of Graphic Processing Units (GPUs) make it possible to have access to high-performance computing solutions at a low cost, allowing their use in many scientific problems. We have implemented an algorithm for 3D reconstruction of CBCT data using the Compute Unified Device Architecture (CUDA) provided by NVIDIA (NVIDIA Corporation, Santa Clara, California), which was executed on a NVIDIA GeForce GTX 280. Our implementation results in improved reconstruction times from minutes, and perhaps hours, to a matter of seconds, while also giving the clinician the ability to view 3D volumetric data at higher resolutions. We evaluated our implementation on ten clinical data sets and one phantom data set to observe if differences occur between CPU and GPU-based reconstructions. By using our approach, the computation time for 256(3) is reduced from 25 min on the CPU to 3.2 s on the GPU. The GPU reconstruction time for 512(3) volumes is 8.5 s. Copyright 2009 Elsevier Ireland Ltd. All rights reserved.

Nasal computed tomography.

PubMed

Kuehn, Ned F

2006-05-01

Chronic nasal disease is often a challenge to diagnose. Computed tomography greatly enhances the ability to diagnose chronic nasal disease in dogs and cats. Nasal computed tomography provides detailed information regarding the extent of disease, accurate discrimination of neoplastic versus nonneoplastic diseases, and identification of areas of the nose to examine rhinoscopically and suspicious regions to target for biopsy.

Multislice Computed Tomography Accurately Detects Stenosis in Coronary Artery Bypass Conduits

PubMed Central

Duran, Cihan; Sagbas, Ertan; Caynak, Baris; Sanisoglu, Ilhan; Akpinar, Belhhan; Gulbaran, Murat

2007-01-01

The aim of this study was to evaluate the accuracy of multislice computed tomography in detecting graft stenosis or occlusion after coronary artery bypass grafting, using coronary angiography as the standard. From January 2005 through May 2006, 25 patients (19 men and 6 women; mean age, 54 ± 11.3 years) underwent diagnostic investigation of their bypass grafts by multislice computed tomography within 1 month of coronary angiography. The mean time elapsed after coronary artery bypass grafting was 6.2 years. In these 25 patients, we examined 65 bypass conduits (24 arterial and 41 venous) and 171 graft segments (the shaft, proximal anastomosis, and distal anastomosis). Compared with coronary angiography, the segment-based sensitivity, specificity, and positive and negative predictive values of multislice computed tomography in the evaluation of stenosis were 89%, 100%, 100%, and 99%, respectively. The patency rate for multislice compu-ted tomography was 85% (55/65: 3 arterial and 7 venous grafts were occluded), with 100% sensitivity and specificity. From these data, we conclude that multislice computed tomography can accurately evaluate the patency and stenosis of bypass grafts during outpatient follow-up. PMID:17948078

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

Blume-Kohout, Robin J.; Gamble, John King; Nielsen, Erik

Quantum tomography is used to characterize quantum operations implemented in quantum information processing (QIP) hardware. Traditionally, state tomography has been used to characterize the quantum state prepared in an initialization procedure, while quantum process tomography is used to characterize dynamical operations on a QIP system. As such, tomography is critical to the development of QIP hardware (since it is necessary both for debugging and validating as-built devices, and its results are used to influence the next generation of devices). But tomography suffers from several critical drawbacks. In this report, we present new research that resolves several of these flaws. Wemore » describe a new form of tomography called gate set tomography (GST), which unifies state and process tomography, avoids prior methods critical reliance on precalibrated operations that are not generally available, and can achieve unprecedented accuracies. We report on theory and experimental development of adaptive tomography protocols that achieve far higher fidelity in state reconstruction than non-adaptive methods. Finally, we present a new theoretical and experimental analysis of process tomography on multispin systems, and demonstrate how to more effectively detect and characterize quantum noise using carefully tailored ensembles of input states.« less

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.

Materials challenges for repeatable RF wireless device reconfiguration with microfluidic channels

NASA Astrophysics Data System (ADS)

Griffin, Anthony S.; Sottos, Nancy R.; White, Scott R.

2018-03-01

Recently, adaptive wireless devices have utilized displacement of EGaIn within microchannels as an electrical switching mechanism to enable reconfigurable electronics. Device reconfiguration using EGaIn in microchannels overcomes many challenges encountered by more traditional reconfiguration mechanisms such as diodes and microelectromechanical systems (MEMS). Reconfiguration using EGaIn is severely limited by undesired permanent shorting due to retention of the liquid in microchannels caused by wetting and rapid oxide skin formation. Here, we investigate the conditions which prevent repeatable electrical switching using EGaIn in microchannels. Initial contact angle tests of EGaIn on epoxy surfaces demonstrate the wettability of EGaIn on flat surfaces. SEM cross-sections of microchannels reveal adhesion of EGaIn residue to channel walls. Micro-computed tomography (microCT) scans of provide volumetric measurements of EGaIn remaining inside channels after flow cycling. Non-wetting coatings are proposed as materials based strategy to overcome these issues in future work.

Innovations in surgical stone disease.

PubMed

Antonelli, Jodi A

2016-05-01

Urinary stone disease is a condition characterized by a rich history of surgical innovation. Herein, we review the new ideas, devices and methods that are the cornerstones of contemporary surgical innovation in stone disease, specifically flexible ureteroscopy and percutaneous nephrolithotomy. The new ideas being applied to flexible ureteroscopy include extending the boundaries of surgical indications and eliminating the need for intraoperative fluoroscopy. Device advancements include disposable ureteroscopes and flexi semirigid ureteroscopes. Robotic flexible ureteroscopy, the use of magnets and mobile technology applications represent progress in methods of performing flexible ureteroscopy. Three-dimensional computed tomography and printing technology are enhancing percutaneous renal access. Novel image-guided access techniques are improving the accuracy of percutaneous surgery particularly for complex cases. New ideas, devices and methods are continuing to reshape the landscape of surgical stone treatment and in so doing not only have the potential to improve surgical outcomes but also to cultivate further scientific and technological advancements in this area.

Microwave ablation devices for interventional oncology.

PubMed

Ward, Robert C; Healey, Terrance T; Dupuy, Damian E

2013-03-01

Microwave ablation is one of the several options in the ablation armamentarium for the treatment of malignancy, offering several potential benefits when compared with other ablation, radiation, surgical and medical treatment modalities. The basic microwave system consists of the generator, power distribution system and antennas. Often under image (computed tomography or ultrasound) guidance, a needle-like antenna is inserted percutaneously into the tumor, where local microwave electromagnetic radiation is emitted from the probe's active tip, producing frictional tissue heating, capable of causing cell death by coagulation necrosis. Half of the microwave ablation systems use a 915 MHz generator and the other half use a 2450 MHz generator. To date, there are no completed clinical trials comparing microwave devices head-to-head. Prospective comparisons of microwave technology with other treatment alternatives, as well as head-to-head comparison with each microwave device, is needed if this promising field will garner more widespread support and use in the oncology community.

Stabilization of the Abdominal Aorta During the Cardiac Cycle with the Sac-Anchoring Nellix Device.

PubMed

Itoga, Nathan K; Suh, Ga-Young; Cheng, Christopher P

2018-06-09

The Nellix device uses polymer-filled endobags to stabilize the abdominal aortic aneurysm (AAA) sac which is described as endovascular aneurysm sealing (EVAS). We analyzed cardiac-gated computed tomography angiography scans of repaired AAA with EVAS in 4 patients to evaluate the geometry and cardiac pulsatility-induced deformation. Graft translation and aortic curvature changes were found to be minimal during the cardiac cycle. The mean ± standard deviation changes in renal-aorta angles (1.0 ± 0.9°) were less than the changes in the superior mesenteric artery-aorta angle (4.0 ± 2.1°) (P < 0.01), during the cardiac cycle, demonstrating greater stabilization of the visceral branches closer to the device. These findings confirm stabilization of the abdominal aorta during the cardiac cycle using EVAS. Copyright © 2018 Elsevier Inc. All rights reserved.

Differences between postmortem computed tomography and conventional autopsy in a stabbing murder case

PubMed Central

Zerbini, Talita; da Silva, Luiz Fernando Ferraz; Ferro, Antonio Carlos Gonçalves; Kay, Fernando Uliana; Junior, Edson Amaro; Pasqualucci, Carlos Augusto Gonçalves; do Nascimento Saldiva, Paulo Hilario

2014-01-01

OBJECTIVE: The aim of the present work is to analyze the differences and similarities between the elements of a conventional autopsy and images obtained from postmortem computed tomography in a case of a homicide stab wound. METHOD: Comparison between the findings of different methods: autopsy and postmortem computed tomography. RESULTS: In some aspects, autopsy is still superior to imaging, especially in relation to external examination and the description of lesion vitality. However, the findings of gas embolism, pneumothorax and pulmonary emphysema and the relationship between the internal path of the instrument of aggression and the entry wound are better demonstrated by postmortem computed tomography. CONCLUSIONS: Although multislice computed tomography has greater accuracy than autopsy, we believe that the conventional autopsy method is fundamental for providing evidence in criminal investigations. PMID:25518020

Interlaced X-ray diffraction computed tomography

PubMed Central

Vamvakeros, Antonios; Jacques, Simon D. M.; Di Michiel, Marco; Senecal, Pierre; Middelkoop, Vesna; Cernik, Robert J.; Beale, Andrew M.

2016-01-01

An X-ray diffraction computed tomography data-collection strategy that allows, post experiment, a choice between temporal and spatial resolution is reported. This strategy enables time-resolved studies on comparatively short timescales, or alternatively allows for improved spatial resolution if the system under study, or components within it, appear to be unchanging. The application of the method for studying an Mn–Na–W/SiO2 fixed-bed reactor in situ is demonstrated. Additionally, the opportunities to improve the data-collection strategy further, enabling post-collection tuning between statistical, temporal and spatial resolutions, are discussed. In principle, the interlaced scanning approach can also be applied to other pencil-beam tomographic techniques, like X-ray fluorescence computed tomography, X-ray absorption fine structure computed tomography, pair distribution function computed tomography and tomographic scanning transmission X-ray microscopy. PMID:27047305

Colovesical fistula causing an uncommon reason for failure of computed tomography colonography: a case report.

PubMed

Neroladaki, Angeliki; Breguet, Romain; Botsikas, Diomidis; Terraz, Sylvain; Becker, Christoph D; Montet, Xavier

2012-07-23

Computed tomography colonography, or virtual colonoscopy, is a good alternative to optical colonoscopy. However, suboptimal patient preparation or colon distension may reduce the diagnostic accuracy of this imaging technique. We report the case of an 83-year-old Caucasian woman who presented with a five-month history of pneumaturia and fecaluria and an acute episode of macrohematuria, leading to a high clinical suspicion of a colovesical fistula. The fistula was confirmed by standard contrast-enhanced computed tomography. Optical colonoscopy was performed to exclude the presence of an underlying colonic neoplasm. Since optical colonoscopy was incomplete, computed tomography colonography was performed, but also failed due to inadequate colon distension. The insufflated air directly accumulated within the bladder via the large fistula. Clinicians should consider colovesical fistula as a potential reason for computed tomography colonography failure.

Computed tomography and (18)F-fluorodeoxyglucose positron emission tomography/computed tomography findings in adrenal candidiasis and histoplasmosis: two cases.

PubMed

Altinmakas, Emre; Guo, Ming; Kundu, Uma R; Habra, Mouhammed Amir; Ng, Chaan

2015-01-01

We report the contrast-enhanced computed tomography (CT) and (18)F-fluorodeoxyglucose positron emission tomography findings in adrenal histoplasmosis and candidiasis. Both demonstrated bilateral hypermetabolic heterogeneous adrenal masses with limited wash-out on delayed CT. Adrenal candidiasis has not been previously reported, nor have the CT wash-out findings in either infection. The adrenal imaging findings are indistinguishable from malignancy, which is more common; but in this setting, physicians should be alert to the differential diagnosis of fungal infections, since it can be equally deadly. Published by Elsevier Inc.

Incidental renal tumours on low-dose CT lung cancer screening exams.

PubMed

Pinsky, Paul F; Dunn, Barbara; Gierada, David; Nath, P Hrudaya; Munden, Reginald; Berland, Lincoln; Kramer, Barnett S

2017-06-01

Introduction Renal cancer incidence has increased markedly in the United States in recent decades, largely due to incidentally detected tumours from computed tomography imaging. Here, we analyze the potential for low-dose computed tomography lung cancer screening to detect renal cancer. Methods The National Lung Screening Trial randomized subjects to three annual screens with either low-dose computed tomography or chest X-ray. Eligibility criteria included 30 + pack-years, current smoking or quit within 15 years, and age 55-74. Subjects were followed for seven years. Low-dose computed tomography screening forms collected information on lung cancer and non-lung cancer abnormalities, including abnormalities below the diaphragm. A reader study was performed on a sample of National Lung Screening Trial low-dose computed tomography images assessing presence of abnormalities below the diaphragms and abnormalities suspicious for renal cancer. Results There were 26,722 and 26,732 subjects enrolled in the low-dose computed tomography and chest X-ray arms, respectively, and there were 104 and 85 renal cancer cases diagnosed, respectively (relative risk = 1.22, 95% CI: 0.9-1.5). From 75,126 low-dose computed tomography screens, there were 46 renal cancer diagnoses within one year. Abnormalities below the diaphragm rates were 39.1% in screens with renal cancer versus 4.1% in screens without (P < 0.001). Cases with abnormalities below the diaphragms had shorter median time to diagnosis than those without (71 vs. 160 days, P = 0.004). In the reader study, 64% of renal cancer cases versus 13% of non-cases had abnormalities below the diaphragms; 55% of cases and 0.8% of non-cases had a finding suspicious for renal cancer (P < 0.001). Conclusion Low-dose computed tomography screens can potentially detect renal cancers. The benefits to harms tradeoff of incidental detection of renal tumours on low-dose computed tomography is unknown.

Meta-Analysis of Stress Myocardial Perfusion Imaging

ClinicalTrials.gov

2017-06-06

Coronary Disease; Echocardiography; Fractional Flow Reserve, Myocardial; Hemodynamics; Humans; Magnetic Resonance Imaging; Myocardial Perfusion Imaging; Perfusion; Predictive Value of Tests; Single Photon Emission Computed Tomography; Positron Emission Tomography; Multidetector Computed Tomography; Echocardiography, Stress; Coronary Angiography

Positron Computed Tomography: Current State, Clinical Results and Future Trends

DOE R&D Accomplishments Database

Schelbert, H. R.; Phelps, M. E.; Kuhl, D. E.

1980-09-01

An overview is presented of positron computed tomography: its advantages over single photon emission tomography, its use in metabolic studies of the heart and chemical investigation of the brain, and future trends. (ACR)

Woodmetrics: imaging devices and processes in wood inspection at Lulea University of Technology

NASA Astrophysics Data System (ADS)

Hagman, Olle

1999-09-01

Wood Technology research and education at Lulea University of Technology is located in Skelleftea 800 km north of Stockholm. At the campus about 25 persons are involved in education and research in Wood Technology. We are educating M.Sc. and post- graduate students in Wood Technology. The research at the campus includes the following main fields: -- Wood Machining - - Woodmetrics -- Wood Drying -- Wood Composites/Wood Material Science. Our research strategy is to obtain an individual treatment of every tree, board and piece of wood in order to get highest possible value for the forest products. This shall be accomplished by the aid of advanced scanning technology and computer technology. Woodmetrics means to measure different wood parameters in order to optimize the utilization of the raw material. Today we have the following projects in this field: Automatic wood inspection -- Color changes and moisture flow in drying processes -- Inner quality of logs and lumber - - Stem quality database -- Computer tomography -- Aesthetic properties of wood -- Market/industry/forest relations. In the Woodmetrics field we are using computer tomography, CCD cameras and other sensors in order to find and measure defects in trees and on boards. The signals are analyzed and classified with modern image analyzing techniques and advanced statistical methods.

Diagnostic dilemma of degenerative joint disease, chronic avascular necrosis or metastasis in planar Tc-99m-methylene diphosphonate planar skeletal scintigraphy excluded by single positron emission computed tomography/computed tomography.

PubMed

Jain, Tarun Kumar; Phulsunga, Rohit Kumar; Basher, Rajender Kumar; Kumar, Narendra; Bhattacharya, Anish; Mittal, Bhagwant Rai

2015-01-01

We present a 71-year-old male patient subjected to skeletal scintigraphy for metastasis work up of prostate cancer. Whole body planar images revealed a solitary focal tracer uptake in left femoral head mimicking as solitary metastatic focus. Single positron emission computed tomography/computed tomography images localized this increased tracer uptake to the subchondral cysts with minimal sclerosis in left femur head with no decrease in size of femur head and was reported as (degenerative joint disease).

Diagnostic dilemma of degenerative joint disease, chronic avascular necrosis or metastasis in planar Tc-99m-methylene diphosphonate planar skeletal scintigraphy excluded by single positron emission computed tomography/computed tomography

PubMed Central

Jain, Tarun Kumar; Phulsunga, Rohit Kumar; Basher, Rajender Kumar; Kumar, Narendra; Bhattacharya, Anish; Mittal, Bhagwant Rai

2015-01-01

We present a 71-year-old male patient subjected to skeletal scintigraphy for metastasis work up of prostate cancer. Whole body planar images revealed a solitary focal tracer uptake in left femoral head mimicking as solitary metastatic focus. Single positron emission computed tomography/computed tomography images localized this increased tracer uptake to the subchondral cysts with minimal sclerosis in left femur head with no decrease in size of femur head and was reported as (degenerative joint disease). PMID:26170582

The early development of medial coronoid disease in growing Labrador retrievers: radiographic, computed tomographic, necropsy and micro-computed tomographic findings.

PubMed

Lau, S F; Wolschrijn, C F; Hazewinkel, H A W; Siebelt, M; Voorhout, G

2013-09-01

Medial coronoid disease (MCD) encompasses lesions of the entire medial coronoid process (MCP), both of the articular cartilage and the subchondral bone. To detect the earliest signs of MCD, radiography and computed tomography were used to monitor the development of MCD in 14 Labrador retrievers, from 6 to 7 weeks of age until euthanasia. The definitive diagnosis of MCD was based on necropsy and micro-computed tomography findings. The frequency of MCD in the dogs studied was 50%. Radiographic findings did not provide evidence of MCD, ulnar subtrochlear sclerosis or blunting of the cranial edge of the MCP. Computed tomography was more sensitive (30.8%) than radiography (0%) in detecting early MCD, with the earliest signs detectable at 14 weeks of age. A combination of the necropsy and micro-computed tomography findings of the MCP showed that MCD was manifested as a lesion of only the subchondral bone in dogs <18 weeks of age. In all dogs (affected and unaffected), there was close contact between the base of the MCP and the proximal radial head in the congruent joints. Computed tomography and micro-computed tomography findings indicated that the lesions of MCD probably originated at the base of the MCP. Copyright © 2013 Elsevier Ltd. All rights reserved.

Optical Fiber Transmission In A Picture Archiving And Communication System For Medical Applications

NASA Astrophysics Data System (ADS)

Aaron, Gilles; Bonnard, Rene

1984-03-01

In an hospital, the need for an electronic communication network is increasing along with the digitization of pictures. This local area network is intended to link some picture sources such as digital radiography, computed tomography, nuclear magnetic resonance, ultrasounds etc...with an archiving system. Interactive displays can be used in examination rooms, physicians offices and clinics. In such a system, three major requirements must be considered : bit-rate, cable length, and number of devices. - The bit-rate is very important because a maximum response time of a few seconds must be guaranteed for several mega-bit pictures. - The distance between nodes may be a few kilometers in some large hospitals. - The number of devices connected to the network is never greater than a few tens because picture sources and computers represent important hardware, and simple displays can be concentrated. All these conditions are fulfilled by optical fiber transmissions. Depending on the topology and the access protocol, two solutions are to be considered - Active ring - Active or passive star Finally Thomson-CSF developments of optical transmission devices for large networks of TV distribution bring us a technological support and a mass produc-tion which will cut down hardware costs.

One-stage tooth-borne distraction versus two stage bone-borne distraction in surgically assisted maxillary expansion (SARME).

PubMed

Seeberger, Robin; Abe-Nickler, Dorothee; Hoffmann, Jürgen; Kunzmann, Kevin; Zingler, Sebastian

2015-12-01

To evaluate and compare the effects of tooth-borne and bone-borne distraction devices in surgically assisted maxillary expansion (SARME) on dental and skeletal structures. A sample of 33 skeletally mature patients with transverse maxillary deficiencies was examined with cone beam computed tomography (CBCT) before and 3 months after surgery. Fourteen patients were treated with tooth-borne devices and 19 patients with bone-borne devices. Dental crown expansion in the first premolars did not differ significantly between the two groups, and median expansion was 5.55 mm (interquartile range [IQR] 5.23) in the tooth-borne device group and 4.6 mm (IQR 3.4) in the bone-borne device group. In the first molars, crown expansion and lateral tipping were significantly greater in the tooth-borne device group (P ≤ .02). The median skeletal nasal isthmus increase was significantly more in the bone-borne device group at 3.0 mm than in the tooth-borne device group at 0.98 mm (P ≤ .02). Both tooth-borne and bone-borne devices are effective treatment modalities to correct maxillary transverse deficiencies. Bone-borne devices produced greater widening of the skeletal nasal floor and fewer dental side effects in the first molars. Copyright © 2015 Elsevier Inc. All rights reserved.

A Smartphone Client-Server Teleradiology System for Primary Diagnosis of Acute Stroke

PubMed Central

2011-01-01

Background Recent advances in the treatment of acute ischemic stroke have made rapid acquisition, visualization, and interpretation of images a key factor for positive patient outcomes. We have developed a new teleradiology system based on a client-server architecture that enables rapid access to interactive advanced 2-D and 3-D visualization on a current generation smartphone device (Apple iPhone or iPod Touch, or an Android phone) without requiring patient image data to be stored on the device. Instead, a server loads and renders the patient images, then transmits a rendered frame to the remote device. Objective Our objective was to determine if a new smartphone client-server teleradiology system is capable of providing accuracies and interpretation times sufficient for diagnosis of acute stroke. Methods This was a retrospective study. We obtained 120 recent consecutive noncontrast computed tomography (NCCT) brain scans and 70 computed tomography angiogram (CTA) head scans from the Calgary Stroke Program database. Scans were read by two neuroradiologists, one on a medical diagnostic workstation and an iPod or iPhone (hereafter referred to as an iOS device) and the other only on an iOS device. NCCT brain scans were evaluated for early signs of infarction, which includes early parenchymal ischemic changes and dense vessel sign, and to exclude acute intraparenchymal hemorrhage and stroke mimics. CTA brain scans were evaluated for any intracranial vessel occlusion. The interpretations made on an iOS device were compared with those made at a workstation. The total interpretation times were recorded for both platforms. Interrater agreement was assessed. True positives, true negatives, false positives, and false negatives were obtained, and sensitivity, specificity, and accuracy of detecting the abnormalities on the iOS device were computed. Results The sensitivity, specificity, and accuracy of detecting intraparenchymal hemorrhage were 100% using the iOS device with a perfect interrater agreement (kappa = 1). The sensitivity, specificity, and accuracy of detecting acute parenchymal ischemic change were 94.1%, 100%, and 98.09% respectively for reader 1 and 97.05%, 100%, and 99.04% for reader 2 with nearly perfect interrater agreement (kappa = .8). The sensitivity, specificity, and accuracy of detecting dense vessel sign were 100%, 95.4%, and 96.19% respectively for reader 1 and 72.2%, 100%, and 95.23% for reader 2 using the iOS device with a good interrater agreement (kappa = .69). The sensitivity, specificity, and accuracy of detecting vessel occlusion on CT angiography scans were 94.4%, 100%, and 98.46% respectively for both readers using the iOS device, with perfect interrater agreement (kappa = 1). No significant difference (P < .05) was noted in the interpretation time between the workstation and iOS device. Conclusion The smartphone client-server teleradiology system appears promising and may have the potential to allow urgent management decisions in acute stroke. However, this study was retrospective, involved relatively few patient studies, and only two readers. Generalizing conclusions about its clinical utility, especially in other diagnostic use cases, should not be made until additional studies are performed. PMID:21550961

A smartphone client-server teleradiology system for primary diagnosis of acute stroke.

PubMed

Mitchell, J Ross; Sharma, Pranshu; Modi, Jayesh; Simpson, Mark; Thomas, Monroe; Hill, Michael D; Goyal, Mayank

2011-05-06

Recent advances in the treatment of acute ischemic stroke have made rapid acquisition, visualization, and interpretation of images a key factor for positive patient outcomes. We have developed a new teleradiology system based on a client-server architecture that enables rapid access to interactive advanced 2-D and 3-D visualization on a current generation smartphone device (Apple iPhone or iPod Touch, or an Android phone) without requiring patient image data to be stored on the device. Instead, a server loads and renders the patient images, then transmits a rendered frame to the remote device. Our objective was to determine if a new smartphone client-server teleradiology system is capable of providing accuracies and interpretation times sufficient for diagnosis of acute stroke. This was a retrospective study. We obtained 120 recent consecutive noncontrast computed tomography (NCCT) brain scans and 70 computed tomography angiogram (CTA) head scans from the Calgary Stroke Program database. Scans were read by two neuroradiologists, one on a medical diagnostic workstation and an iPod or iPhone (hereafter referred to as an iOS device) and the other only on an iOS device. NCCT brain scans were evaluated for early signs of infarction, which includes early parenchymal ischemic changes and dense vessel sign, and to exclude acute intraparenchymal hemorrhage and stroke mimics. CTA brain scans were evaluated for any intracranial vessel occlusion. The interpretations made on an iOS device were compared with those made at a workstation. The total interpretation times were recorded for both platforms. Interrater agreement was assessed. True positives, true negatives, false positives, and false negatives were obtained, and sensitivity, specificity, and accuracy of detecting the abnormalities on the iOS device were computed. The sensitivity, specificity, and accuracy of detecting intraparenchymal hemorrhage were 100% using the iOS device with a perfect interrater agreement (kappa=1). The sensitivity, specificity, and accuracy of detecting acute parenchymal ischemic change were 94.1%, 100%, and 98.09% respectively for reader 1 and 97.05%, 100%, and 99.04% for reader 2 with nearly perfect interrater agreement (kappa=.8). The sensitivity, specificity, and accuracy of detecting dense vessel sign were 100%, 95.4%, and 96.19% respectively for reader 1 and 72.2%, 100%, and 95.23% for reader 2 using the iOS device with a good interrater agreement (kappa=.69). The sensitivity, specificity, and accuracy of detecting vessel occlusion on CT angiography scans were 94.4%, 100%, and 98.46% respectively for both readers using the iOS device, with perfect interrater agreement (kappa=1). No significant difference (P<.05) was noted in the interpretation time between the workstation and iOS device. The smartphone client-server teleradiology system appears promising and may have the potential to allow urgent management decisions in acute stroke. However, this study was retrospective, involved relatively few patient studies, and only two readers. Generalizing conclusions about its clinical utility, especially in other diagnostic use cases, should not be made until additional studies are performed. ©J Ross Mitchell, Pranshu Sharma, Jayesh Modi, Mark Simpson, Monroe Thomas, Michael D. Hill, Mayank Goyal.

Tomography in Geology: 3D Modeling and Analysis of Structural Features of Rocks Using Computed MicroTomography

NASA Astrophysics Data System (ADS)

Ponomarev, A. A.; Mamadaliev, R. A.; Semenova, T. V.

2016-10-01

The article presents a brief overview of the current state of computed tomography in the sphere of oil and gas production in Russia and in the world. Operation of computed microtomograph Skyscan 1172 is also provided, as well as personal examples of its application in solving geological problems.

Aerosolized intranasal midazolam for safe and effective sedation for quality computed tomography imaging in infants and children.

PubMed

Mekitarian Filho, Eduardo; de Carvalho, Werther Brunow; Gilio, Alfredo Elias; Robinson, Fay; Mason, Keira P

2013-10-01

This pilot study introduces the aerosolized route for midazolam as an option for infant and pediatric sedation for computed tomography imaging. This technique produced predictable and effective sedation for quality computed tomography imaging studies with minimal artifact and no significant adverse events. Copyright © 2013 Mosby, Inc. All rights reserved.

Computed Tomography Measuring Inside Machines

NASA Technical Reports Server (NTRS)

Wozniak, James F.; Scudder, Henry J.; Anders, Jeffrey E.

1995-01-01

Computed tomography applied to obtain approximate measurements of radial distances from centerline of turbopump to leading edges of diffuser vanes in turbopump. Use of computed tomography has significance beyond turbopump application: example of general concept of measuring internal dimensions of assembly of parts without having to perform time-consuming task of taking assembly apart and measuring internal parts on coordinate-measuring machine.

A Heat Pipe Coupled Planar Thermionic Converter: Performance Characterization, Nondestructive Testing, and Evaluation.

DTIC Science & Technology

1992-03-15

Pipes, Computer Modelling, Nondestructive Testing. Tomography , Planar Converter, Cesium Reservoir 19. ABSTRACT (Continue on reverse if necessary and...Investigation ........................ 32 4.3 Computed Tomography ................................ 33 4.4 X-Ray Radiography...25 3.4 LEOS generated output data for Mo-Re converter ................ 26 4.1 Distance along converter imaged by the computed tomography

Nondestructive microimaging during preclinical pin-on-plate testing of novel materials for arthroplasty.

PubMed

Teeter, Matthew G; Langohr, G Daniel G; Medley, John B; Holdsworth, David W

2014-02-01

The purpose of this study was to determine the ability of micro-computed tomography to quantify wear in preclinical pin-on-plate testing of materials for use in joint arthroplasty. Wear testing of CoCr pins articulating against six polyetheretherketone plates was performed using a pin-on-plate apparatus over 2 million cycles. Change in volume due to wear was quantified with gravimetric analysis and with micro-computed tomography, and the volumes were compared. Separately, the volume of polyetheretherketone pin-on-plate specimens that had been soaking in fluid for 52 weeks was quantified with both gravimetric analysis and micro-computed tomography, and repeated after drying. The volume change with micro-computed tomography was compared to the mass change with gravimetric analysis. The mean wear volume measured was 8.02 ± 6.38 mm(3) with gravimetric analysis and 6.76 ± 5.38 mm(3) with micro-computed tomography (p = 0.06). Micro-computed tomography volume measurements did not show a statistically significant change with drying for either the plates (p = 0.60) or the pins (p = 0.09), yet drying had a significant effect on the gravimetric mass measurements for both the plates (p = 0.03) and the pins (p = 0.04). Micro-computed tomography provided accurate measurements of wear in polyetheretherketone pin-on-plate test specimens, and no statistically significant change was caused by fluid uptake. Micro-computed tomography quantifies wear depth and wear volume, mapped to the specific location of damage on the specimen, and is also capable of examining subsurface density as well as cracking. Its noncontact, nondestructive nature makes it ideal for preclinical testing of materials, in which further additional analysis techniques may be utilized.

Preoperative (3-dimensional) computed tomography lung reconstruction before anatomic segmentectomy or lobectomy for stage I non-small cell lung cancer.

PubMed

Chan, Ernest G; Landreneau, James R; Schuchert, Matthew J; Odell, David D; Gu, Suicheng; Pu, Jiantao; Luketich, James D; Landreneau, Rodney J

2015-09-01

Accurate cancer localization and negative resection margins are necessary for successful segmentectomy. In this study, we evaluate a newly developed software package that permits automated segmentation of the pulmonary parenchyma, allowing 3-dimensional assessment of tumor size, location, and estimates of surgical margins. A pilot study using a newly developed 3-dimensional computed tomography analytic software package was performed to retrospectively evaluate preoperative computed tomography images of patients who underwent segmentectomy (n = 36) or lobectomy (n = 15) for stage 1 non-small cell lung cancer. The software accomplishes an automated reconstruction of anatomic pulmonary segments of the lung based on bronchial arborization. Estimates of anticipated surgical margins and pulmonary segmental volume were made on the basis of 3-dimensional reconstruction. Autosegmentation was achieved in 72.7% (32/44) of preoperative computed tomography images with slice thicknesses of 3 mm or less. Reasons for segmentation failure included local severe emphysema or pneumonitis, and lower computed tomography resolution. Tumor segmental localization was achieved in all autosegmented studies. The 3-dimensional computed tomography analysis provided a positive predictive value of 87% in predicting a marginal clearance greater than 1 cm and a 75% positive predictive value in predicting a margin to tumor diameter ratio greater than 1 in relation to the surgical pathology assessment. This preoperative 3-dimensional computed tomography analysis of segmental anatomy can confirm the tumor location within an anatomic segment and aid in predicting surgical margins. This 3-dimensional computed tomography information may assist in the preoperative assessment regarding the suitability of segmentectomy for peripheral lung cancers. Published by Elsevier Inc.

Role of post-mapping computed tomography in virtual-assisted lung mapping.

PubMed

Sato, Masaaki; Nagayama, Kazuhiro; Kuwano, Hideki; Nitadori, Jun-Ichi; Anraku, Masaki; Nakajima, Jun

2017-02-01

Background Virtual-assisted lung mapping is a novel bronchoscopic preoperative lung marking technique in which virtual bronchoscopy is used to predict the locations of multiple dye markings. Post-mapping computed tomography is performed to confirm the locations of the actual markings. This study aimed to examine the accuracy of marking locations predicted by virtual bronchoscopy and elucidate the role of post-mapping computed tomography. Methods Automated and manual virtual bronchoscopy was used to predict marking locations. After bronchoscopic dye marking under local anesthesia, computed tomography was performed to confirm the actual marking locations before surgery. Discrepancies between marking locations predicted by the different methods and the actual markings were examined on computed tomography images. Forty-three markings in 11 patients were analyzed. Results The average difference between the predicted and actual marking locations was 30 mm. There was no significant difference between the latest version of the automated virtual bronchoscopy system (30.7 ± 17.2 mm) and manual virtual bronchoscopy (29.8 ± 19.1 mm). The difference was significantly greater in the upper vs. lower lobes (37.1 ± 20.1 vs. 23.0 ± 6.8 mm, for automated virtual bronchoscopy; p < 0.01). Despite this discrepancy, all targeted lesions were successfully resected using 3-dimensional image guidance based on post-mapping computed tomography reflecting the actual marking locations. Conclusions Markings predicted by virtual bronchoscopy were dislocated from the actual markings by an average of 3 cm. However, surgery was accurately performed using post-mapping computed tomography guidance, demonstrating the indispensable role of post-mapping computed tomography in virtual-assisted lung mapping.

Utility of screening computed tomography of chest, abdomen and pelvis in patients after heart transplantation.

PubMed

Dasari, Tarun W; Pavlovic-Surjancev, Biljana; Dusek, Linda; Patel, Nilamkumar; Heroux, Alain L

2011-12-01

Malignancy is a late cause of mortality in heart transplant recipients. It is unknown if screening computed tomography scan would lead to early detection of such malignancies or serious vascular anomalies post heart transplantation. This is a single center observational study of patients undergoing surveillance computed tomography of chest, abdomen and pelvis at least 5 years after transplantation. Abnormal findings, included pulmonary nodules, lymphadenopathy and intra-thoracic and intra-abdominal masses and vascular anomalies such as abdominal aortic aneurysm. The clinical follow up of each of these major abnormal findings is summarized. A total of 63 patients underwent computed tomography scan of chest, abdomen and pelvis at least 5 years after transplantation. Of these, 54 (86%) were male and 9 (14%) were female. Mean age was 52±9.2 years. Computed tomography revealed 1 lung cancer (squamous cell) only. Non specific pulmonary nodules were seen in 6 patients (9.5%). The most common incidental finding was abdominal aortic aneurysms (N=6 (9.5%)), which necessitated follow up computed tomography (N=5) or surgery (N=1). Mean time to detection of abdominal aortic aneurysms from transplantation was 14.6±4.2 years. Mean age at the time of detection of abdominal aortic aneurysms was 74.5±3.2 years. Screening computed tomography scan in patients 5 years from transplantation revealed only one malignancy but lead to increased detection of abdominal aortic aneurysms. Thus the utility is low in terms of detection of malignancy. Based on this study we do not recommend routine computed tomography post heart transplantation. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Petamenophis (Padiamenemipet), an Egyptian Child Mummy Protected for Eternity: Revelation by Multidetector Computed Tomography.

PubMed

Martina, Maria Cristina; Cesarani, Federico; Boano, Rosa; Fiore Marochetti, Elisa; Gandini, Giovanni

The objective of our work was to report the most recent findings obtained with multidetector computed tomography of a child mummy from the Roman period (119-123 CE) housed at the Egyptian Museum in Turin, Italy. Multidetector computed tomography and postprocessing were applied to understand the embalming techniques, the nature of a foreign object, and anthropometrical values. The information was compared with that from other mummies that were buried in the same tomb, but today housed in different museums. New information regarding the embalming technique was revealed. Multidetector computed tomography allowed the identification of a knife-like metallic object, probably an amulet for the child's protection in the afterlife. Multidetector computed tomography and image postprocessing confirm their valuable role in noninvasive studies in ancient mummies and provided evidence of a unique cultural practice in the late history of Ancient Egypt such as placing a knife possibly as an amulet.

Self-testing through EPR-steering

NASA Astrophysics Data System (ADS)

Šupić, Ivan; Hoban, Matty J.

2016-07-01

The verification of quantum devices is an important aspect of quantum information, especially with the emergence of more advanced experimental implementations of quantum computation and secure communication. Within this, the theory of device-independent robust self-testing via Bell tests has reached a level of maturity now that many quantum states and measurements can be verified without direct access to the quantum systems: interaction with the devices is solely classical. However, the requirements for this robust level of verification are daunting and require high levels of experimental accuracy. In this paper we discuss the possibility of self-testing where we only have direct access to one part of the quantum device. This motivates the study of self-testing via EPR-steering, an intermediate form of entanglement verification between full state tomography and Bell tests. Quantum non-locality implies EPR-steering so results in the former can apply in the latter, but we ask what advantages may be gleaned from the latter over the former given that one can do partial state tomography? We show that in the case of self-testing a maximally entangled two-qubit state, or ebit, EPR-steering allows for simpler analysis and better error tolerance than in the case of full device-independence. On the other hand, this improvement is only a constant improvement and (up to constants) is the best one can hope for. Finally, we indicate that the main advantage in self-testing based on EPR-steering could be in the case of self-testing multi-partite quantum states and measurements. For example, it may be easier to establish a tensor product structure for a particular party’s Hilbert space even if we do not have access to their part of the global quantum system.

Background-Oriented Schlieren for Large-Scale and High-Speed Aerodynamic Phenomena

NASA Technical Reports Server (NTRS)

Mizukaki, Toshiharu; Borg, Stephen; Danehy, Paul M.; Murman, Scott M.; Matsumura, Tomoharu; Wakabayashi, Kunihiko; Nakayama, Yoshio

2015-01-01

Visualization of the flow field around a generic re-entry capsule in subsonic flow and shock wave visualization with cylindrical explosives have been conducted to demonstrate sensitivity and applicability of background-oriented schlieren (BOS) for field experiments. The wind tunnel experiment suggests that BOS with a fine-pixel imaging device has a density change detection sensitivity on the order of 10(sup -5) in subsonic flow. In a laboratory setup, the structure of the shock waves generated by explosives have been successfully reconstructed by a computed tomography method combined with BOS.

The contribution of Medical Physics to Nuclear Medicine: looking back - a physicist's perspective.

PubMed

Hutton, Brian F

2014-12-01

This paper is the first in a series of invited perspectives by four pioneers of Nuclear Medicine imaging and physics. A medical physicist and a Nuclear Medicine clinical specialist each take a backward look and a forward look at the contributions of Medical Physics to Nuclear Medicine. Contributions of Medical Physics are presented from the early discovery of radioactivity, development of first imaging devices, computers and emission tomography to recent development of hybrid imaging. There is evidence of significant contribution of Medical Physics throughout the development of Nuclear Medicine.

Diagnosis of sinusoidal obstruction syndrome by positron emission tomography/computed tomography: report of two cases treated by defibrotide.

PubMed

Gauthé, Mathieu; Bozec, Laurence; Bedossa, Pierre

2014-11-01

Sinusoidal obstruction syndrome (SOS) is a potentially fatal liver injury that mainly occurs after myeloablative chemotherapy. We report two cases of SOS investigated by 18F-fluorodeoxyglucose positron emission tomography/computed tomography and treated with defibrotide. © 2014 by the American Association for the Study of Liver Diseases.

Measuring Weld Profiles By Computer Tomography

NASA Technical Reports Server (NTRS)

Pascua, Antonio G.; Roy, Jagatjit

1990-01-01

Noncontacting, nondestructive computer tomography system determines internal and external contours of welded objects. System makes it unnecessary to take metallurgical sections (destructive technique) or to take silicone impressions of hidden surfaces (technique that contaminates) to inspect them. Measurements of contours via tomography performed 10 times as fast as measurements via impression molds, and tomography does not contaminate inspected parts.

Parallel Computing for the Computed-Tomography Imaging Spectrometer

NASA Technical Reports Server (NTRS)

Lee, Seungwon

2008-01-01

This software computes the tomographic reconstruction of spatial-spectral data from raw detector images of the Computed-Tomography Imaging Spectrometer (CTIS), which enables transient-level, multi-spectral imaging by capturing spatial and spectral information in a single snapshot.

[The comparison of the expansion of polyps according to the Ki-67 and computed tomography scores].

PubMed

Aydin, Sedat; Sanli, Arif; Tezer, Ilter; Hardal, Umit; Barişik, Nagehan Ozdemir

2009-01-01

The disease extention in nasal polyps was compared by using the mitotic activity rates and the computed tomography scores. This study was conducted on 19 nasal polyposis patients (8 males, 11 females; mean age 40.0+/-13.7 years; range 20 to 63 years). The preoperative computed tomography records of the patients were evaluated according to the Lund-Mackay grading system. The polyp tissues of the same patients were stained with the Ki-67 antigen for immunohistochemical evaluation. The correlation between the radiologic results and the Ki-67 values was compared by means of the Spearman's correlation test. The mean computed tomography score was observed as 14.3+/-4.7 (range 7-24). The mean Ki-67 score resulting from the immunohistochemical staining was calculated as 24.3+/-18.5 (range 3.3-73.5%). A significant correlation was determined between the Ki-67 values and the computed tomography scores. ("Spearman's" correlation factor: 0.677; p<0.001). As the mitotic activity rate of nasal polyps increases, both the volume of the polyps and the computed tomography scores increase as a result of the blockage of the sinus ostiums by the increased polyp volume.

A Projection Quality-Driven Tube Current Modulation Method in Cone-Beam CT for IGRT: Proof of Concept.

PubMed

Men, Kuo; Dai, Jianrong

2017-12-01

To develop a projection quality-driven tube current modulation method in cone-beam computed tomography for image-guided radiotherapy based on the prior attenuation information obtained by the planning computed tomography and then evaluate its effect on a reduction in the imaging dose. The QCKV-1 phantom with different thicknesses (0-400 mm) of solid water upon it was used to simulate different attenuation (μ). Projections were acquired with a series of tube current-exposure time product (mAs) settings, and a 2-dimensional contrast to noise ratio was analyzed for each projection to create a lookup table of mAs versus 2-dimensional contrast to noise ratio, μ. Before a patient underwent computed tomography, the maximum attenuation [Formula: see text] within the 95% range of each projection angle (θ) was estimated according to the planning computed tomography images. Then, a desired 2-dimensional contrast to noise ratio value was selected, and the mAs setting at θ was calculated with the lookup table of mAs versus 2-dimensional contrast to noise ratio,[Formula: see text]. Three-dimensional cone-beam computed tomography images were reconstructed using the projections acquired with the selected mAs. The imaging dose was evaluated with a polymethyl methacrylate dosimetry phantom in terms of volume computed tomography dose index. Image quality was analyzed using a Catphan 503 phantom with an oval body annulus and a pelvis phantom. For the Catphan 503 phantom, the cone-beam computed tomography image obtained by the projection quality-driven tube current modulation method had a similar quality to that of conventional cone-beam computed tomography . However, the proposed method could reduce the imaging dose by 16% to 33% to achieve an equivalent contrast to noise ratio value. For the pelvis phantom, the structural similarity index was 0.992 with a dose reduction of 39.7% for the projection quality-driven tube current modulation method. The proposed method could reduce the additional dose to the patient while not degrading the image quality for cone-beam computed tomography. The projection quality-driven tube current modulation method could be especially beneficial to patients who undergo cone-beam computed tomography frequently during a treatment course.

Granular computing with multiple granular layers for brain big data processing.

PubMed

Wang, Guoyin; Xu, Ji

2014-12-01

Big data is the term for a collection of datasets so huge and complex that it becomes difficult to be processed using on-hand theoretical models and technique tools. Brain big data is one of the most typical, important big data collected using powerful equipments of functional magnetic resonance imaging, multichannel electroencephalography, magnetoencephalography, Positron emission tomography, near infrared spectroscopic imaging, as well as other various devices. Granular computing with multiple granular layers, referred to as multi-granular computing (MGrC) for short hereafter, is an emerging computing paradigm of information processing, which simulates the multi-granular intelligent thinking model of human brain. It concerns the processing of complex information entities called information granules, which arise in the process of data abstraction and derivation of information and even knowledge from data. This paper analyzes three basic mechanisms of MGrC, namely granularity optimization, granularity conversion, and multi-granularity joint computation, and discusses the potential of introducing MGrC into intelligent processing of brain big data.

Luggage and shipped goods.

PubMed

Vogel, H; Haller, D

2007-08-01

Control of luggage and shipped goods are frequently carried out. The possibilities of X-ray technology shall be demonstrated. There are different imaging techniques. The main concepts are transmission imaging, backscatter imaging, computed tomography, and dual energy imaging and the combination of different methods The images come from manufacturers and personal collections. The search concerns mainly, weapons, explosives, and drugs; furthermore animals, and stolen goods, Special problems offer the control of letters and the detection of Improvised Explosive Devices (IED). One has to expect that controls will increase and that imaging with X-rays will have their part. Pattern recognition software will be used for analysis enforced by economy and by demand for higher efficiency - man and computer will produce more security than man alone.

Wireless, Web-Based Interactive Control of Optical Coherence Tomography with Mobile Devices.

PubMed

Mehta, Rajvi; Nankivil, Derek; Zielinski, David J; Waterman, Gar; Keller, Brenton; Limkakeng, Alexander T; Kopper, Regis; Izatt, Joseph A; Kuo, Anthony N

2017-01-01

Optical coherence tomography (OCT) is widely used in ophthalmology clinics and has potential for more general medical settings and remote diagnostics. In anticipation of remote applications, we developed wireless interactive control of an OCT system using mobile devices. A web-based user interface (WebUI) was developed to interact with a handheld OCT system. The WebUI consisted of key OCT displays and controls ported to a webpage using HTML and JavaScript. Client-server relationships were created between the WebUI and the OCT system computer. The WebUI was accessed on a cellular phone mounted to the handheld OCT probe to wirelessly control the OCT system. Twenty subjects were imaged using the WebUI to assess the system. System latency was measured using different connection types (wireless 802.11n only, wireless to remote virtual private network [VPN], and cellular). Using a cellular phone, the WebUI was successfully used to capture posterior eye OCT images in all subjects. Simultaneous interactivity by a remote user on a laptop was also demonstrated. On average, use of the WebUI added only 58, 95, and 170 ms to the system latency using wireless only, wireless to VPN, and cellular connections, respectively. Qualitatively, operator usage was not affected. Using a WebUI, we demonstrated wireless and remote control of an OCT system with mobile devices. The web and open source software tools used in this project make it possible for any mobile device to potentially control an OCT system through a WebUI. This platform can be a basis for remote, teleophthalmology applications using OCT.

Quantum gate-set tomography

NASA Astrophysics Data System (ADS)

Blume-Kohout, Robin

2014-03-01

Quantum information technology is built on (1) physical qubits and (2) precise, accurate quantum logic gates that transform their states. Developing quantum logic gates requires good characterization - both in the development phase, where we need to identify a device's flaws so as to fix them, and in the production phase, where we need to make sure that the device works within specs and predict residual error rates and types. This task falls to quantum state and process tomography. But until recently, protocols for tomography relied on a pre-existing and perfectly calibrated reference frame comprising the measurements (and, for process tomography, input states) used to characterize the device. In practice, these measurements are neither independent nor perfectly known - they are usually implemented via exactly the same gates that we are trying to characterize! In the past year, several partial solutions to this self-consistency problem have been proposed. I will present a framework (gate set tomography, or GST) that addresses and resolves this problem, by self-consistently characterizing an entire set of quantum logic gates on a black-box quantum device. In particular, it contains an explicit closed-form protocol for linear-inversion gate set tomography (LGST), which is immune to both calibration error and technical pathologies like local maxima of the likelihood (which plagued earlier methods). GST also demonstrates significant (multiple orders of magnitude) improvements in efficiency over standard tomography by using data derived from long sequences of gates (much like randomized benchmarking). GST has now been applied to qubit devices in multiple technologies. I will present and discuss results of GST experiments in technologies including a single trapped-ion qubit and a silicon quantum dot qubit. Sandia National Laboratories is a multiprogram laboratory operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL850.

Recent advances in electron tomography: TEM and HAADF-STEM tomography for materials science and semiconductor applications.

PubMed

Kübel, Christian; Voigt, Andreas; Schoenmakers, Remco; Otten, Max; Su, David; Lee, Tan-Chen; Carlsson, Anna; Bradley, John

2005-10-01

Electron tomography is a well-established technique for three-dimensional structure determination of (almost) amorphous specimens in life sciences applications. With the recent advances in nanotechnology and the semiconductor industry, there is also an increasing need for high-resolution three-dimensional (3D) structural information in physical sciences. In this article, we evaluate the capabilities and limitations of transmission electron microscopy (TEM) and high-angle-annular-dark-field scanning transmission electron microscopy (HAADF-STEM) tomography for the 3D structural characterization of partially crystalline to highly crystalline materials. Our analysis of catalysts, a hydrogen storage material, and different semiconductor devices shows that features with a diameter as small as 1-2 nm can be resolved in three dimensions by electron tomography. For partially crystalline materials with small single crystalline domains, bright-field TEM tomography provides reliable 3D structural information. HAADF-STEM tomography is more versatile and can also be used for high-resolution 3D imaging of highly crystalline materials such as semiconductor devices.

X-ray tomography system to investigate granular materials during mechanical loading

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

Athanassiadis, Athanasios G.; Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139; La Rivière, Patrick J.

2014-08-15

We integrate a small and portable medical x-ray device with mechanical testing equipment to enable in situ, non-invasive measurements of a granular material's response to mechanical loading. We employ an orthopedic C-arm as the x-ray source and detector to image samples mounted in the materials tester. We discuss the design of a custom rotation stage, which allows for sample rotation and tomographic reconstruction under applied compressive stress. We then discuss the calibration of the system for 3D computed tomography, as well as the subsequent image reconstruction process. Using this system to reconstruct packings of 3D-printed particles, we resolve packing featuresmore » with 0.52 mm resolution in a (60 mm){sup 3} field of view. By analyzing the performance bounds of the system, we demonstrate that the reconstructions exhibit only moderate noise.« less

Positron Emission Tomography of the Heart

DOE R&D Accomplishments Database

Schelbert, H. R.; Phelps, M. E.; Kuhl, D. E.

1979-01-01

Positron emission computed tomography (PCT) represents an important new tool for the noninvasive evaluation and, more importantly, quantification of myocardial performance. Most currently available techniques permit assessment of only one aspect of cardiac function, i.e., myocardial perfusion by gamma scintillation camera imaging with Thallium-201 or left ventricular function by echocardiography or radionuclide angiocardiography. With PCT it may become possible to study all three major segments of myocardial performance, i.e., regional blood flow, mechanical function and, most importantly, myocardial metabolism. Each of these segments can either be evaluated separately or in combination. This report briefly describes the principles and technological advantages of the imaging device, reviews currently available radioactive tracers and how they can be employed for the assessment of flow, function and metabolism; and, lastly, discusses possible applications of PCT for the study of cardiac physiology or its potential role in the diagnosis of cardiac disease.

Attenuation correction in emission tomography using the emission data—A review

PubMed Central

Li, Yusheng

2016-01-01

The problem of attenuation correction (AC) for quantitative positron emission tomography (PET) had been considered solved to a large extent after the commercial availability of devices combining PET with computed tomography (CT) in 2001; single photon emission computed tomography (SPECT) has seen a similar development. However, stimulated in particular by technical advances toward clinical systems combining PET and magnetic resonance imaging (MRI), research interest in alternative approaches for PET AC has grown substantially in the last years. In this comprehensive literature review, the authors first present theoretical results with relevance to simultaneous reconstruction of attenuation and activity. The authors then look back at the early history of this research area especially in PET; since this history is closely interwoven with that of similar approaches in SPECT, these will also be covered. We then review algorithmic advances in PET, including analytic and iterative algorithms. The analytic approaches are either based on the Helgason–Ludwig data consistency conditions of the Radon transform, or generalizations of John’s partial differential equation; with respect to iterative methods, we discuss maximum likelihood reconstruction of attenuation and activity (MLAA), the maximum likelihood attenuation correction factors (MLACF) algorithm, and their offspring. The description of methods is followed by a structured account of applications for simultaneous reconstruction techniques: this discussion covers organ-specific applications, applications specific to PET/MRI, applications using supplemental transmission information, and motion-aware applications. After briefly summarizing SPECT applications, we consider recent developments using emission data other than unscattered photons. In summary, developments using time-of-flight (TOF) PET emission data for AC have shown promising advances and open a wide range of applications. These techniques may both remedy deficiencies of purely MRI-based AC approaches in PET/MRI and improve standalone PET imaging. PMID:26843243

PATIENT STUDY OF IN VIVO VERIFICATION OF BEAM DELIVERY AND RANGE, USING POSITRON EMISSION TOMOGRAPHY AND COMPUTED TOMOGRAPHY IMAGING AFTER PROTON THERAPY

PubMed Central

Parodi, Katia; Paganetti, Harald; Shih, Helen A.; Michaud, Susan; Loeffler, Jay S.; Delaney, Thomas F.; Liebsch, Norbert J.; Munzenrider, John E.; Fischman, Alan J.; Knopf, Antje; Bortfeld, Thomas

2007-01-01

Purpose To investigate the feasibility and value of positron emission tomography and computed tomography (PET/CT) for treatment verification after proton radiotherapy. Methods and Materials This study included 9 patients with tumors in the cranial base, spine, orbit, and eye. Total doses of 1.8–3 GyE and 10 GyE (for an ocular melanoma) per fraction were delivered in 1 or 2 fields. Imaging was performed with a commercial PET/CT scanner for 30 min, starting within 20 min after treatment. The same treatment immobilization device was used during imaging for all but 2 patients. Measured PET/CT images were coregistered to the planning CT and compared with the corresponding PET expectation, obtained from CT-based Monte Carlo calculations complemented by functional information. For the ocular case, treatment position was approximately replicated, and spatial correlation was deduced from reference clips visible in both the planning radiographs and imaging CT. Here, the expected PET image was obtained from an analytical model. Results Good spatial correlation and quantitative agreement within 30% were found between the measured and expected activity. For head-and-neck patients, the beam range could be verified with an accuracy of 1–2 mm in well-coregistered bony structures. Low spine and eye sites indicated the need for better fixation and coregistration methods. An analysis of activity decay revealed as tissue-effective half-lives of 800–1,150 s. Conclusions This study demonstrates the feasibility of postradiation PET/CT for in vivo treatment verification. It also indicates some technological and methodological improvements needed for optimal clinical application. PMID:17544003

Attenuation correction in emission tomography using the emission data—A review

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

Berker, Yannick, E-mail: berker@mail.med.upenn.edu; Li, Yusheng

2016-02-15

The problem of attenuation correction (AC) for quantitative positron emission tomography (PET) had been considered solved to a large extent after the commercial availability of devices combining PET with computed tomography (CT) in 2001; single photon emission computed tomography (SPECT) has seen a similar development. However, stimulated in particular by technical advances toward clinical systems combining PET and magnetic resonance imaging (MRI), research interest in alternative approaches for PET AC has grown substantially in the last years. In this comprehensive literature review, the authors first present theoretical results with relevance to simultaneous reconstruction of attenuation and activity. The authors thenmore » look back at the early history of this research area especially in PET; since this history is closely interwoven with that of similar approaches in SPECT, these will also be covered. We then review algorithmic advances in PET, including analytic and iterative algorithms. The analytic approaches are either based on the Helgason–Ludwig data consistency conditions of the Radon transform, or generalizations of John’s partial differential equation; with respect to iterative methods, we discuss maximum likelihood reconstruction of attenuation and activity (MLAA), the maximum likelihood attenuation correction factors (MLACF) algorithm, and their offspring. The description of methods is followed by a structured account of applications for simultaneous reconstruction techniques: this discussion covers organ-specific applications, applications specific to PET/MRI, applications using supplemental transmission information, and motion-aware applications. After briefly summarizing SPECT applications, we consider recent developments using emission data other than unscattered photons. In summary, developments using time-of-flight (TOF) PET emission data for AC have shown promising advances and open a wide range of applications. These techniques may both remedy deficiencies of purely MRI-based AC approaches in PET/MRI and improve standalone PET imaging.« less

Just Scan It!-Weapon Reconstruction in Computed Tomography on Historical and Current Swiss Military Guns.

PubMed

Franckenberg, Sabine; Binder, Thomas; Bolliger, Stephan; Thali, Michael J; Ross, Steffen G

2016-09-01

Cross-sectional imaging, such as computed tomography, has been increasingly implemented in both historic and recent postmortem forensic investigations. It aids in determining cause and manner of death as well as in correlating injuries to possible weapons. This study illuminates the feasibility of reconstructing guns in computed tomography and gives a distinct overview of historic and recent Swiss Army guns.

The use of computed tomography to diagnose chronic shoulder arthritis in an American white pelican (Pelecanus erythrorhynchos).

PubMed

Whitehead, Michelle C; Parker, Dennilyn L

2015-03-01

An American white pelican was presented with a complete left wing droop and no abnormal findings on conventional radiography. Computed tomography was used to diagnose chronic shoulder arthritis as a sequela to a suspected traumatic compressive fracture. This is the first case report to describe use of computed tomography to evaluate the avian shoulder joint.

Embracing Statistical Challenges in the Information Technology Age

DTIC Science & Technology

2006-01-01

computation and feature selection. Moreover, two research projects on network tomography and arctic cloud detection are used throughout the paper to bring...prominent Network Tomography problem, origin- destination (OD) traffic estimation. It demonstrates well how the two modes of data collection interact...software debugging (Biblit et al, 2005 [2]), and network tomography for computer network management. Computer sys- tem problems exist long before the IT

Computed Tomography For Internal Inspection Of Castings

NASA Technical Reports Server (NTRS)

Hanna, Timothy L.

1995-01-01

Computed tomography used to detect internal flaws in metal castings before machining and otherwise processing them into finished parts. Saves time and money otherwise wasted on machining and other processing of castings eventually rejected because of internal defects. Knowledge of internal defects gained by use of computed tomography also provides guidance for changes in foundry techniques, procedures, and equipment to minimize defects and reduce costs.

The Impact of Computed Tomography on Decision Making in Tibial Plateau Fractures.

PubMed

Castiglia, Marcello Teixeira; Nogueira-Barbosa, Marcello Henrique; Messias, Andre Marcio Vieira; Salim, Rodrigo; Fogagnolo, Fabricio; Schatzker, Joseph; Kfuri, Mauricio

2018-02-14

Schatzker introduced one of the most used classification systems for tibial plateau fractures, based on plain radiographs. Computed tomography brought to attention the importance of coronal plane-oriented fractures. The goal of our study was to determine if the addition of computed tomography would affect the decision making of surgeons who usually use the Schatzker classification to assess tibial plateau fractures. Image studies of 70 patients who sustained tibial plateau fractures were uploaded to a dedicated homepage. Every patient was linked to a folder which contained two radiographic projections (anteroposterior and lateral), three interactive videos of computed tomography (axial, sagittal, and coronal), and eight pictures depicting tridimensional reconstructions of the tibial plateau. Ten attending orthopaedic surgeons, who were blinded to the cases, were granted access to the homepage and assessed each set of images in two different rounds, separated to each other by an interval of 2 weeks. Each case was evaluated in three steps, where surgeons had access, respectively to radiographs, two-dimensional videos of computed tomography, and three-dimensional reconstruction images. After every step, surgeons were asked to present how would they classify the case using the Schatzker system and which surgical approaches would be appropriate. We evaluated the inter- and intraobserver reliability of the Schatzker classification using the Kappa concordance coefficient, as well as the impact of computed tomography in the decision making regarding the surgical approach for each case, by using the chi-square test and likelihood ratio. The interobserver concordance kappa coefficients after each assessment step were, respectively, 0.58, 0.62, and 0.64. For the intraobserver analysis, the coefficients were, respectively, 0.76, 0.75, and 0.78. Computed tomography changed the surgical approach selection for the types II, V, and VI of Schatzker ( p  < 0.01). The addition of computed tomography scans to plain radiographs improved the interobserver reliability of Schatzker classification. Computed tomography had a statistically significant impact in the selection of surgical approaches for the lateral tibial plateau. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Image quality in low-dose coronary computed tomography angiography with a new high-definition CT scanner.

PubMed

Kazakauskaite, Egle; Husmann, Lars; Stehli, Julia; Fuchs, Tobias; Fiechter, Michael; Klaeser, Bernd; Ghadri, Jelena R; Gebhard, Catherine; Gaemperli, Oliver; Kaufmann, Philipp A

2013-02-01

A new generation of high definition computed tomography (HDCT) 64-slice devices complemented by a new iterative image reconstruction algorithm-adaptive statistical iterative reconstruction, offer substantially higher resolution compared to standard definition CT (SDCT) scanners. As high resolution confers higher noise we have compared image quality and radiation dose of coronary computed tomography angiography (CCTA) from HDCT versus SDCT. Consecutive patients (n = 93) underwent HDCT, and were compared to 93 patients who had previously undergone CCTA with SDCT matched for heart rate (HR), HR variability and body mass index (BMI). Tube voltage and current were adapted to the patient's BMI, using identical protocols in both groups. The image quality of all CCTA scans was evaluated by two independent readers in all coronary segments using a 4-point scale (1, excellent image quality; 2, blurring of the vessel wall; 3, image with artefacts but evaluative; 4, non-evaluative). Effective radiation dose was calculated from DLP multiplied by a conversion factor (0.014 mSv/mGy × cm). The mean image quality score from HDCT versus SDCT was comparable (2.02 ± 0.68 vs. 2.00 ± 0.76). Mean effective radiation dose did not significantly differ between HDCT (1.7 ± 0.6 mSv, range 1.0-3.7 mSv) and SDCT (1.9 ± 0.8 mSv, range 0.8-5.5 mSv; P = n.s.). HDCT scanners allow low-dose 64-slice CCTA scanning with higher resolution than SDCT but maintained image quality and equally low radiation dose. Whether this will translate into higher accuracy of HDCT for CAD detection remains to be evaluated.

Dual source and dual detector arrays tetrahedron beam computed tomography for image guided radiotherapy.

PubMed

Kim, Joshua; Lu, Weiguo; Zhang, Tiezhi

2014-02-07

Cone-beam computed tomography (CBCT) is an important online imaging modality for image guided radiotherapy. But suboptimal image quality and the lack of a real-time stereoscopic imaging function limit its implementation in advanced treatment techniques, such as online adaptive and 4D radiotherapy. Tetrahedron beam computed tomography (TBCT) is a novel online imaging modality designed to improve on the image quality provided by CBCT. TBCT geometry is flexible, and multiple detector and source arrays can be used for different applications. In this paper, we describe a novel dual source-dual detector TBCT system that is specially designed for LINAC radiation treatment machines. The imaging system is positioned in-line with the MV beam and is composed of two linear array x-ray sources mounted aside the electrical portal imaging device and two linear arrays of x-ray detectors mounted below the machine head. The detector and x-ray source arrays are orthogonal to each other, and each pair of source and detector arrays forms a tetrahedral volume. Four planer images can be obtained from different view angles at each gantry position at a frame rate as high as 20 frames per second. The overlapped regions provide a stereoscopic field of view of approximately 10-15 cm. With a half gantry rotation, a volumetric CT image can be reconstructed having a 45 cm field of view. Due to the scatter rejecting design of the TBCT geometry, the system can potentially produce high quality 2D and 3D images with less radiation exposure. The design of the dual source-dual detector system is described, and preliminary results of studies performed on numerical phantoms and simulated patient data are presented.

Dual source and dual detector arrays tetrahedron beam computed tomography for image guided radiotherapy

NASA Astrophysics Data System (ADS)

Kim, Joshua; Lu, Weiguo; Zhang, Tiezhi

2014-02-01

Cone-beam computed tomography (CBCT) is an important online imaging modality for image guided radiotherapy. But suboptimal image quality and the lack of a real-time stereoscopic imaging function limit its implementation in advanced treatment techniques, such as online adaptive and 4D radiotherapy. Tetrahedron beam computed tomography (TBCT) is a novel online imaging modality designed to improve on the image quality provided by CBCT. TBCT geometry is flexible, and multiple detector and source arrays can be used for different applications. In this paper, we describe a novel dual source-dual detector TBCT system that is specially designed for LINAC radiation treatment machines. The imaging system is positioned in-line with the MV beam and is composed of two linear array x-ray sources mounted aside the electrical portal imaging device and two linear arrays of x-ray detectors mounted below the machine head. The detector and x-ray source arrays are orthogonal to each other, and each pair of source and detector arrays forms a tetrahedral volume. Four planer images can be obtained from different view angles at each gantry position at a frame rate as high as 20 frames per second. The overlapped regions provide a stereoscopic field of view of approximately 10-15 cm. With a half gantry rotation, a volumetric CT image can be reconstructed having a 45 cm field of view. Due to the scatter rejecting design of the TBCT geometry, the system can potentially produce high quality 2D and 3D images with less radiation exposure. The design of the dual source-dual detector system is described, and preliminary results of studies performed on numerical phantoms and simulated patient data are presented.

Flat-detector computed tomography evaluation in an experimental animal aneurysm model after endovascular treatment: A pilot study.

PubMed

Ott, Sabine; Gölitz, Philipp; Adamek, Edyta; Royalty, Kevin; Doerfler, Arnd; Struffert, Tobias

2015-08-01

We compared flat-detector computed tomography angiography (FD-CTA) to multislice computed tomography (MS-CTA) and digital subtracted angiography (DSA) for the visualization of experimental aneurysms treated with stents, coils or a combination of both.In 20 rabbits, aneurysms were created using the rabbit elastase aneurysm model. Seven aneurysms were treated with coils, seven with coils and stents, and six with self-expandable stents alone. Imaging was performed by DSA, MS-CTA and FD-CTA immediately after treatment. Multiplanar reconstruction (MPR) was performed and two experienced reviewers compared aneurysm/coil package size, aneurysm occlusion, stent diameters and artifacts for each modality.In aneurysms treated with stents alone, the visualization of the aneurysms was identical in all three imaging modalities. Residual aneurysm perfusion was present in two cases and visible in DSA and FD-CTA but not in MS-CTA. The diameter of coil-packages was overestimated in MS-CT by 56% and only by 16% in FD-CTA compared to DSA (p < 0.05). The diameter of stents was identical for DSA and FD-CTA and was significantly overestimated in MS-CTA (p < 0.05). Beam/metal hardening artifacts impaired image quality more severely in MS-CTA compared to FD-CTA.MS-CTA is impaired by blooming and beam/metal hardening artifacts in the visualization of implanted devices. There was no significant difference between measurements made with noninvasive FD-CTA compared to gold standard of DSA after stenting and after coiling/stent-assisted coiling of aneurysms. FD-CTA may be considered as a non-invasive alternative to the gold standard 2D DSA in selected patients that require follow up imaging after stenting. © The Author(s) 2015.

Limitations of PET/CT in the Detection of Occult N1 Metastasis in Clinical Stage I(T1-2aN0) Non-Small Cell Lung Cancer for Staging Prior to Stereotactic Body Radiotherapy.

PubMed

Akthar, Adil S; Ferguson, Mark K; Koshy, Matthew; Vigneswaran, Wickii T; Malik, Renuka

2017-02-01

Patients receiving stereotactic body radiotherapy for stage I non-small cell lung cancer are typically staged clinically with positron emission tomography-computed tomography. Currently, limited data exist for the detection of occult hilar/peribronchial (N1) disease. We hypothesize that positron emission tomography-computed tomography underestimates spread of cancer to N1 lymph nodes and that future stereotactic body radiotherapy patients may benefit from increased pathologic evaluation of N1 nodal stations in addition to N2 nodes. A retrospective study was performed of all patients with clinical stage I (T1-2aN0) non-small cell lung cancer (American Joint Committee on Cancer, 7th edition) by positron emission tomography-computed tomography at our institution from 2003 to 2011, with subsequent surgical resection and lymph node staging. Findings on positron emission tomography-computed tomography were compared to pathologic nodal involvement to determine the negative predictive value of positron emission tomography-computed tomography for the detection of N1 nodal disease. An analysis was conducted to identify predictors of occult spread. A total of 105 patients with clinical stage I non-small cell lung cancer were included in this study, of which 8 (7.6%) patients were found to have occult N1 metastasis on pathologic review yielding a negative predictive value for N1 disease of 92.4%. No patients had occult mediastinal nodes. The negative predictive value for positron emission tomography-computed tomography in patients with clinical stage T1 versus T2 tumors was 72 (96%) of 75 versus 25 (83%) of 30, respectively ( P = .03), and for peripheral versus central tumor location was 77 (98%) of 78 versus 20 (74%) of 27, respectively ( P = .0001). The negative predictive values for peripheral T1 and T2 tumors were 98% and 100%, respectively; while for central T1 and T2 tumors, the rates were 85% and 64%, respectively. Occult lymph node involvement was not associated with primary tumor maximum standard uptake value, histology, grade, or interval between positron emission tomography-computed tomography and surgery. Our results support pathologic assessment of N1 lymph nodes in patients with stage Inon-small cell lung cancer considered for stereotactic body radiotherapy, with the greatest benefit in patients with central and T2 tumors. Diagnostic evaluation with endoscopic bronchial ultrasound should be considered in the evaluation of stereotactic body radiotherapy candidates.

Postmortem whole-body computed tomography angiography visualizing vascular rupture in a case of fatal car crash.

PubMed

Flach, Patricia M; Ross, Steffen G; Bolliger, Stephan A; Preiss, Ulrich S; Thali, Michael J; Spendlove, Danny

2010-01-01

In addition to the increasingly significant role of multislice computed tomography in forensic pathology, the performance of whole-body computed tomography angiography provides outstanding results. In this case, we were able to detect multiple injuries of the parenchymal organs in the upper abdomen as well as lesions of the brain parenchyma and vasculature of the neck. The radiologic findings showed complete concordance with the autopsy and even supplemented the autopsy findings in areas that are difficult to access via a manual dissection (such as the vasculature of the neck). This case shows how minimally invasive computed tomography angiography can serve as an invaluable adjunct to the classic autopsy procedure.

Computed tomography in the evaluation of Crohn disease

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

Goldberg, H.I.; Gore, R.M.; Margulis, A.R.

1983-02-01

The abdominal and pelvic computed tomographic examinations in 28 patients with Crohn disease were analyzed and correlated with conventional barium studies, sinograms, and surgical findings. Mucosal abnormalities such as aphthous lesions, pseudopolyps, and ulcerations were only imaged by conventional techniques. Computed tomography proved superior in demonstrating the mural, serosal, and mesenteric abnormalities such as bowel wall thickening (82%), fibrofatty proliferation of mesenteric fat (39%), mesenteric abscess (25%), inflammatory reaction of the mesentery (14%), and mesenteric lymphadenopathy (18%). Computed tomography was most useful clinically in defining the nature of mass effects, separation, or displacement of small bowel segments seen on smallmore » bowel series. Although conventional barium studies remain the initial diagnostic procedure in evaluating Crohn disease, computed tomography can be a useful adjunct in resolving difficult clinical and radiologic diagnostic problems.« less

A Pilot Study of Augmented Reality Technology Applied to the Acetabular Cup Placement During Total Hip Arthroplasty.

PubMed

Ogawa, Hiroyuki; Hasegawa, Seiichirou; Tsukada, Sachiyuki; Matsubara, Masaaki

2018-06-01

We developed an acetabular cup placement device, the AR-HIP system, using augmented reality (AR). The AR-HIP system allows the surgeon to view an acetabular cup image superimposed in the surgical field through a smartphone. The smartphone also shows the placement angle of the acetabular cup. This preliminary study was performed to assess the accuracy of the AR-HIP system for acetabular cup placement during total hip arthroplasty (THA). We prospectively measured the placement angles using both a goniometer and AR-HIP system in 56 hips of 54 patients undergoing primary THA. We randomly determined the order of intraoperative measurement using the 2 devices. At 3 months after THA, the placement angle of the acetabular cup was measured on computed tomography images. The primary outcome was the absolute value of the difference between intraoperative and postoperative computed tomography measurements. The measurement angle using AR-HIP was significantly more accurate in terms of radiographic anteversion than that using a goniometer (2.7° vs 6.8°, respectively; mean difference 4.1°; 95% confidence interval, 3.0-5.2; P < .0001). There was no statistically significant difference in terms of radiographic inclination (2.1° vs 2.6°; mean difference 0.5°; 95% confidence interval, -1.1 to 0.1; P = .13). In this pilot study, the AR-HIP system provided more accurate information regarding acetabular cup placement angle than the conventional method. Further studies are required to confirm the utility of the AR-HIP system as a navigation tool. Copyright © 2018 Elsevier Inc. All rights reserved.

The efficacy of preoperative positron emission tomography-computed tomography (PET-CT) for detection of lymph node metastasis in cervical and endometrial cancer: clinical and pathological factors influencing it.

PubMed

Nogami, Yuya; Banno, Kouji; Irie, Haruko; Iida, Miho; Kisu, Iori; Masugi, Yohei; Tanaka, Kyoko; Tominaga, Eiichiro; Okuda, Shigeo; Murakami, Koji; Aoki, Daisuke

2015-01-01

We studied the diagnostic performance of (18)F-fluoro-2-deoxy-d-glucose-positron emission tomography/computed tomography in cervical and endometrial cancers with particular focus on lymph node metastases. Seventy patients with cervical cancer and 53 with endometrial cancer were imaged with (18)F-fluoro-2-deoxy-D-glucose-positron emission tomography/computed tomography before lymphadenectomy. We evaluated the diagnostic performance of (18)F-fluoro-2-deoxy-D-glucose-positron emission tomography/computed tomography using the final pathological diagnoses as the golden standard. We calculated the sensitivity, specificity, positive predictive value and negative predictive value of (18)F-fluoro-2-deoxy-D-glucose-positron emission tomography/computed tomography. In cervical cancer, the results evaluated by cases were 33.3, 92.7, 55.6 and 83.6%, respectively. When evaluated by the area of lymph nodes, the results were 30.6, 98.9, 55.0 and 97.0%, respectively. As for endometrial cancer, the results evaluated by cases were 50.0, 93.9, 40.0 and 95.8%, and by area of lymph nodes, 45.0, 99.4, 64.3 and 98.5%, respectively. The limitation of the efficacy was found out by analyzing it by the region of the lymph node, the size of metastatic node, the historical type of tumor in cervical cancer and the prevalence of lymph node metastasis. The efficacy of positron emission tomography/computed tomography regarding the detection of lymph node metastasis in cervical and endometrial cancer is not established and has limitations associated with the region of the lymph node, the size of metastasis lesion in lymph node and the pathological type of primary tumor. The indication for the imaging and the interpretation of the results requires consideration for each case by the pretest probability based on the information obtained preoperatively. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Orbital Reconstruction: Patient-Specific Orbital Floor Reconstruction Using a Mirroring Technique and a Customized Titanium Mesh.

PubMed

Tarsitano, Achille; Badiali, Giovanni; Pizzigallo, Angelo; Marchetti, Claudio

2016-10-01

Enophthalmos is a severe complication of primary reconstruction of orbital floor fractures. The goal of secondary reconstruction procedures is to restore symmetrical globe positions to recover function and aesthetics. The authors propose a new method of orbital floor reconstruction using a mirroring technique and a customized titanium mesh, printed using a direct metal laser-sintering method. This reconstructive protocol involves 4 steps: mirroring of the healthy orbit at the affected site, virtual design of a patient-specific orbital floor mesh, CAM procedures for direct laser-sintering of the customized titanium mesh, and surgical insertion of the device. Using a computed tomography data set, the normal, uninjured side of the craniofacial skeleton was reflected onto the contralateral injured side, and a reconstructive orbital floor mesh was designed virtually on the mirrored orbital bone surface. The solid-to-layer files of the mesh were then manufactured using direct metal laser sintering, which resolves the shaping and bending biases inherent in the indirect method. An intraoperative navigation system ensured accuracy of the entire procedure. Clinical outcomes were assessed using 3dMD photogrammetry and computed tomography data in 7 treated patients. The technique described here appears to be a viable method to correct complex orbital floor defects needing delayed reconstruction. This study represents the first step in the development of a wider experimental protocol for orbital floor reconstruction using computer-assisted design-computer-assisted manufacturing technology.

Diagnostic ability of computed tomography using DentaScan software in endodontics: case reports.

PubMed

Siotia, Jaya; Gupta, Sunil K; Acharya, Shashi R; Saraswathi, Vidya

2011-01-01

Radiographic examination is essential in diagnosis and treatment planning in endodontics. Conventional radiographs depict structures in two dimensions only. The ability to assess the area of interest in three dimensions is advantageous. Computed tomography is an imaging technique which produces three-dimensional images of an object by taking a series of two-dimensional sectional X-ray images. DentaScan is a computed tomography software program that allows the mandible and maxilla to be imaged in three planes: axial, panoramic, and cross-sectional. As computed tomography is used in endodontics, DentaScan can play a wider role in endodontic diagnosis. It provides valuable information in the assessment of the morphology of the root canal, diagnosis of root fractures, internal and external resorptions, pre-operative assessment of anatomic structures etc. The aim of this article is to explore the clinical usefulness of computed tomography and DentaScan in endodontic diagnosis, through a series of four cases of different endodontic problems.

Recent Scientific Evidence and Technical Developments in Cardiovascular Computed Tomography.

PubMed

Marcus, Roy; Ruff, Christer; Burgstahler, Christof; Notohamiprodjo, Mike; Nikolaou, Konstantin; Geisler, Tobias; Schroeder, Stephen; Bamberg, Fabian

2016-05-01

In recent years, coronary computed tomography angiography has become an increasingly safe and noninvasive modality for the evaluation of the anatomical structure of the coronary artery tree with diagnostic benefits especially in patients with a low-to-intermediate pretest probability of disease. Currently, increasing evidence from large randomized diagnostic trials is accumulating on the diagnostic impact of computed tomography angiography for the management of patients with acute and stable chest pain syndrome. At the same time, technical advances have substantially reduced adverse effects and limiting factors, such as radiation exposure, the amount of iodinated contrast agent, and scanning time, rendering the technique appropriate for broader clinical applications. In this work, we review the latest developments in computed tomography technology and describe the scientific evidence on the use of cardiac computed tomography angiography to evaluate patients with acute and stable chest pain syndrome. Copyright © 2016 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

Detection of periimplant fenestration and dehiscence with the use of two scan modes and the smallest voxel sizes of a cone-beam computed tomography device.

PubMed

de-Azevedo-Vaz, Sergio Lins; Vasconcelos, Karla de Faria; Neves, Frederico Sampaio; Melo, Saulo Leonardo Sousa; Campos, Paulo Sérgio Flores; Haiter-Neto, Francisco

2013-01-01

To assess the accuracy of cone-beam computed tomography (CBCT) in periimplant fenestration and dehiscence detection, and to determine the effects of 2 voxel sizes and scan modes. One hundred titanium implants were placed in bovine ribs in which periimplant fenestration and dehiscence were simulated. CBCT images were acquired with the use of 3 protocols of the i-CAT NG unit: A) 0.2 mm voxel size half-scan (180°); B) 0.2 mm voxel size full-scan (360°); and C) 0.12 mm voxel size full scan (360°). Receiver operating characteristic curves and diagnostic values were obtained. The Az values were compared with the use of analysis of variance. The Az value for dehiscence in protocol A was significantly lower than those of B or C (P < .01). They did not statistically differ for fenestration (P > .05). Protocol B yielded the highest values. The voxel sizes did not affect fenestration and dehiscence detection, and for dehiscence full-scan performed better than half-scan. Copyright © 2013 Elsevier Inc. All rights reserved.

Computed Tomography Image Origin Identification Based on Original Sensor Pattern Noise and 3-D Image Reconstruction Algorithm Footprints.

PubMed

Duan, Yuping; Bouslimi, Dalel; Yang, Guanyu; Shu, Huazhong; Coatrieux, Gouenou

2017-07-01

In this paper, we focus on the "blind" identification of the computed tomography (CT) scanner that has produced a CT image. To do so, we propose a set of noise features derived from the image chain acquisition and which can be used as CT-scanner footprint. Basically, we propose two approaches. The first one aims at identifying a CT scanner based on an original sensor pattern noise (OSPN) that is intrinsic to the X-ray detectors. The second one identifies an acquisition system based on the way this noise is modified by its three-dimensional (3-D) image reconstruction algorithm. As these reconstruction algorithms are manufacturer dependent and kept secret, our features are used as input to train a support vector machine (SVM) based classifier to discriminate acquisition systems. Experiments conducted on images issued from 15 different CT-scanner models of 4 distinct manufacturers demonstrate that our system identifies the origin of one CT image with a detection rate of at least 94% and that it achieves better performance than sensor pattern noise (SPN) based strategy proposed for general public camera devices.

The fabrication of a customized occlusal splint based on the merging of dynamic jaw tracking records, cone beam computed tomography, and CAD-CAM digital impression.

PubMed

Aslanidou, Katerina; Kau, Chung How; Vlachos, Christos; Saleh, Tayem Abou

2017-01-01

The aim of this case report was to present the procedure of fabricating a customized occlusal splint, through a revolutionary software that combines cone beam computed tomography (CBCT) with jaw motion tracking (JMT) data and superimposes a digital impression. The case report was conducted on a 46-year-old female patient diagnosed with the temporomandibular disorder. A CBCT scan and an optical impression were obtained. The range of the patient's mandibular movements was captured with a JMT device. The data were combined in the SICAT software (SICAT, Sirona, Bonn, Germany). The software enabled the visualization of patient-specific mandibular movements and provided a real dynamic anatomical evaluation of the condylar position in the glenoid fossa. After the assessment of the range of movements during opening, protrusion, and lateral movements all the data were sent to SICAT and a customized occlusal splint was manufactured. The SICAT software provides a three-dimensional real-dynamic simulation of mandibular movements relative to the patient-specific anatomy of the jaw; thus, it opens new possibilities and potentials for the management of temporomandibular disorders.

The effect of photobiomodulation on root resorption during orthodontic treatment.

PubMed

Nimeri, Ghada; Kau, Chung H; Corona, Rachel; Shelly, Jeffery

2014-01-01

Photobiomodulation is used to accelerate tooth movement during orthodontic treatments. The changes in root morphology in a group of orthodontic patients who received photobiomodulation were evaluated using the cone beam computed tomography technique. The device used is called OrthoPulse, which produces low levels of light with a near infrared wavelength of 850 nm and an intensity of 60 mW/cm(2) continuous wave. Twenty orthodontic patients were recruited for these experiments, all with class 1 malocclusion and with Little's Irregularity Index (>2 mm) in either of the arches. Root resorption was detected by measuring changes in tooth length using cone beam computed tomography. These changes were measured before the orthodontic treatment and use of low-level laser therapy and after finishing the alignment level. Little's Irregularity Index for all the patients was calculated in both the maxilla and mandible and patients were divided into three groups for further analysis, which were then compared to the root resorption measurements. Our results showed that photobiomodulation did not cause root resorption greater than the normal range that is commonly detected in orthodontic treatments. Furthermore, no correlation between Little's Irregularity Index and root resorption was detected.

The effect of photobiomodulation on root resorption during orthodontic treatment

PubMed Central

Nimeri, Ghada; Kau, Chung H; Corona, Rachel; Shelly, Jeffery

2014-01-01

Photobiomodulation is used to accelerate tooth movement during orthodontic treatments. The changes in root morphology in a group of orthodontic patients who received photobiomodulation were evaluated using the cone beam computed tomography technique. The device used is called OrthoPulse, which produces low levels of light with a near infrared wavelength of 850 nm and an intensity of 60 mW/cm2 continuous wave. Twenty orthodontic patients were recruited for these experiments, all with class 1 malocclusion and with Little’s Irregularity Index (>2 mm) in either of the arches. Root resorption was detected by measuring changes in tooth length using cone beam computed tomography. These changes were measured before the orthodontic treatment and use of low-level laser therapy and after finishing the alignment level. Little’s Irregularity Index for all the patients was calculated in both the maxilla and mandible and patients were divided into three groups for further analysis, which were then compared to the root resorption measurements. Our results showed that photobiomodulation did not cause root resorption greater than the normal range that is commonly detected in orthodontic treatments. Furthermore, no correlation between Little’s Irregularity Index and root resorption was detected. PMID:24470774

X-ray luminescence computed tomography using a focused x-ray beam.

PubMed

Zhang, Wei; Lun, Michael C; Nguyen, Alex Anh-Tu; Li, Changqing

2017-11-01

Due to the low x-ray photon utilization efficiency and low measurement sensitivity of the electron multiplying charge coupled device camera setup, the collimator-based narrow beam x-ray luminescence computed tomography (XLCT) usually requires a long measurement time. We, for the first time, report a focused x-ray beam-based XLCT imaging system with measurements by a single optical fiber bundle and a photomultiplier tube (PMT). An x-ray tube with a polycapillary lens was used to generate a focused x-ray beam whose x-ray photon density is 1200 times larger than a collimated x-ray beam. An optical fiber bundle was employed to collect and deliver the emitted photons on the phantom surface to the PMT. The total measurement time was reduced to 12.5 min. For numerical simulations of both single and six fiber bundle cases, we were able to reconstruct six targets successfully. For the phantom experiment, two targets with an edge-to-edge distance of 0.4 mm and a center-to-center distance of 0.8 mm were successfully reconstructed by the measurement setup with a single fiber bundle and a PMT. (2017) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).

Dental application of novel finite element analysis software for three-dimensional finite element modeling of a dentulous mandible from its computed tomography images.

PubMed

Nakamura, Keiko; Tajima, Kiyoshi; Chen, Ker-Kong; Nagamatsu, Yuki; Kakigawa, Hiroshi; Masumi, Shin-ich

2013-12-01

This study focused on the application of novel finite-element analysis software for constructing a finite-element model from the computed tomography data of a human dentulous mandible. The finite-element model is necessary for evaluating the mechanical response of the alveolar part of the mandible, resulting from occlusal force applied to the teeth during biting. Commercially available patient-specific general computed tomography-based finite-element analysis software was solely applied to the finite-element analysis for the extraction of computed tomography data. The mandibular bone with teeth was extracted from the original images. Both the enamel and the dentin were extracted after image processing, and the periodontal ligament was created from the segmented dentin. The constructed finite-element model was reasonably accurate using a total of 234,644 nodes and 1,268,784 tetrahedral and 40,665 shell elements. The elastic moduli of the heterogeneous mandibular bone were determined from the bone density data of the computed tomography images. The results suggested that the software applied in this study is both useful and powerful for creating a more accurate three-dimensional finite-element model of a dentulous mandible from the computed tomography data without the need for any other software.

Real-time three-dimensional optical coherence tomography image-guided core-needle biopsy system.

PubMed

Kuo, Wei-Cheng; Kim, Jongsik; Shemonski, Nathan D; Chaney, Eric J; Spillman, Darold R; Boppart, Stephen A

2012-06-01

Advances in optical imaging modalities, such as optical coherence tomography (OCT), enable us to observe tissue microstructure at high resolution and in real time. Currently, core-needle biopsies are guided by external imaging modalities such as ultrasound imaging and x-ray computed tomography (CT) for breast and lung masses, respectively. These image-guided procedures are frequently limited by spatial resolution when using ultrasound imaging, or by temporal resolution (rapid real-time feedback capabilities) when using x-ray CT. One feasible approach is to perform OCT within small gauge needles to optically image tissue microstructure. However, to date, no system or core-needle device has been developed that incorporates both three-dimensional OCT imaging and tissue biopsy within the same needle for true OCT-guided core-needle biopsy. We have developed and demonstrate an integrated core-needle biopsy system that utilizes catheter-based 3-D OCT for real-time image-guidance for target tissue localization, imaging of tissue immediately prior to physical biopsy, and subsequent OCT imaging of the biopsied specimen for immediate assessment at the point-of-care. OCT images of biopsied ex vivo tumor specimens acquired during core-needle placement are correlated with corresponding histology, and computational visualization of arbitrary planes within the 3-D OCT volumes enables feedback on specimen tissue type and biopsy quality. These results demonstrate the potential for using real-time 3-D OCT for needle biopsy guidance by imaging within the needle and tissue during biopsy procedures.

Rib Radiography versus Chest Computed Tomography in the Diagnosis of Rib Fractures.

PubMed

Sano, Atsushi

2018-05-01

 The accurate diagnosis of rib fractures is important in chest trauma. Diagnostic images following chest trauma are usually obtained via chest X-ray, chest computed tomography, or rib radiography. This study evaluated the diagnostic characteristics of rib radiography and chest computed tomography.  Seventy-five rib fracture patients who underwent both chest computed tomography and rib radiography between April 2008 and December 2013 were included. Rib radiographs, centered on the site of pain, were taken from two directions. Chest computed tomography was performed using a 16-row multidetector scanner with 5-mm slice-pitch without overlap, and axial images were visualized in a bone window.  In total, 217 rib fractures were diagnosed in 75 patients. Rib radiography missed 43 rib fractures in 24 patients. The causes were overlap with organs in 15 cases, trivial fractures in 21 cases, and injury outside the imaging range in 7 cases. Left lower rib fractures were often missed due to overlap with the heart, while middle and lower rib fractures were frequently not diagnosed due to overlap with abdominal organs. Computed tomography missed 21 rib fractures in 17 patients. The causes were horizontal fractures in 10 cases, trivial fractures in 9 cases, and insufficient breath holding in 1 case.  In rib radiography, overlap with organs and fractures outside the imaging range were characteristic reasons for missed diagnoses. In chest computed tomography, horizontal rib fractures and insufficient breath holding were often responsible. We should take these challenges into account when diagnosing rib fractures. Georg Thieme Verlag KG Stuttgart · New York.

64 slice-coronary computed tomography sensitivity and specificity in the evaluation of coronary artery bypass graft stenosis: A meta-analysis.

PubMed

Barbero, Umberto; Iannaccone, Mario; d'Ascenzo, Fabrizio; Barbero, Cristina; Mohamed, Abdirashid; Annone, Umberto; Benedetto, Sara; Celentani, Dario; Gagliardi, Marco; Moretti, Claudio; Gaita, Fiorenzo

2016-08-01

A non-invasive approach to define grafts patency and stenosis in the follow-up of coronary artery bypass graft (CABG) patients may be an interesting alternative to coronary angiography. 64-slice-coronary computed tomography is nowadays a diffused non-invasive method that permits an accurate evaluation of coronary stenosis, due to a high temporal and spatial resolution. However, its sensitivity and specificity in CABG evaluation has to be clearly defined, since published studies used different protocols and scanners. We collected all studies investigating patients with stable symptoms and previous CABG and reporting the comparison between diagnostic performances of invasive coronary angiography and 64-slice-coronary computed tomography. As a result, sensitivity and specificity of 64-slice-coronary computed tomography for CABG occlusion were 0.99 (95% CI 0.97-1.00) and 0.99 (95% CI: 0.99-1.00) with an area under the curve (AUC) of 0.99. 64-slice-coronary computed tomography sensitivity and specificity for the presence of any CABG stenosis >50% were 0.98 (95% CI: 0.97-0.99) and 0.98 (95% CI: 0.96-0.98), while AUC was 0.99. At meta-regression, neither the age nor the time from graft implantation had effect on sensitivity and specificity of 64-slice-coronary computed tomography detection of significant CABG stenosis or occlusion. In conclusion 64-slice-coronary computed tomography confirmed its high sensitivity and specificity in CABG stenosis or occlusion evaluation. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Quadruple Axis Neutron Computed Tomography

NASA Astrophysics Data System (ADS)

Schillinger, Burkhard; Bausenwein, Dominik

Neutron computed tomography takes more time for a full tomography than X-rays or Synchrotron radiation, because the source intensity is limited. Most neutron imaging detectors have a square field of view, so if tomography of elongated, narrow samples, e.g. fuel rods, sword blades is recorded, much of the detector area is wasted. Using multiple rotation axes, several samples can be placed inside the field of view, and multiple tomographies can be recorded at the same time by later splitting the recorded images into separate tomography data sets. We describe a new multiple-axis setup using four independent miniaturized rotation tables.

Impact of Single-Photon Emission Computed Tomography/Computed Tomography (SPECT/CT) and Positron Emission Tomography/Computed Tomography (PET/CT) in the Diagnosis of Traumatic Brain Injury (TBI): Case Report.

PubMed

Molina-Vicenty, Irma L; Santiago-Sánchez, Michelaldemar; Vélez-Miró, Iván; Motta-Valencia, Keryl

2016-09-01

Traumatic brain injury (TBI) is defined as damage to the brain resulting from an external force. TBI, a global leading cause of death and disability, is associated with serious social, economic, and health problems. In cases of mild-to-moderate brain damage, conventional anatomical imaging modalities may or may not detect the cascade of metabolic changes that have occurred or are occurring at the intracellular level. Functional nuclear medicine imaging and neurophysiological parameters can be used to characterize brain damage, as the former provides direct visualization of brain function, even in the absence of overt behavioral manifestations or anatomical findings. We report the case of a 30-year-old Hispanic male veteran who, after 2 traumatic brain injury events, developed cognitive and neuropsychological problems with no clear etiology in the presence of negative computed tomography (CT) findings.

A CZT-based blood counter for quantitative molecular imaging.

PubMed

Espagnet, Romain; Frezza, Andrea; Martin, Jean-Pierre; Hamel, Louis-André; Lechippey, Laëtitia; Beauregard, Jean-Mathieu; Després, Philippe

2017-12-01

Robust quantitative analysis in positron emission tomography (PET) and in single-photon emission computed tomography (SPECT) typically requires the time-activity curve as an input function for the pharmacokinetic modeling of tracer uptake. For this purpose, a new automated tool for the determination of blood activity as a function of time is presented. The device, compact enough to be used on the patient bed, relies on a peristaltic pump for continuous blood withdrawal at user-defined rates. Gamma detection is based on a 20 × 20 × 15 mm 3 cadmium zinc telluride (CZT) detector, read by custom-made electronics and a field-programmable gate array-based signal processing unit. A graphical user interface (GUI) allows users to select parameters and easily perform acquisitions. This paper presents the overall design of the device as well as the results related to the detector performance in terms of stability, sensitivity and energy resolution. Results from a patient study are also reported. The device achieved a sensitivity of 7.1 cps/(kBq/mL) and a minimum detectable activity of 2.5 kBq/ml for 18 F. The gamma counter also demonstrated an excellent stability with a deviation in count rates inferior to 0.05% over 6 h. An energy resolution of 8% was achieved at 662 keV. The patient study was conclusive and demonstrated that the compact gamma blood counter developed has the sensitivity and the stability required to conduct quantitative molecular imaging studies in PET and SPECT.

Construction of three-dimensional tooth model by micro-computed tomography and application for data sharing.

PubMed

Kato, A; Ohno, N

2009-03-01

The study of dental morphology is essential in terms of phylogeny. Advances in three-dimensional (3D) measurement devices have enabled us to make 3D images of teeth without destruction of samples. However, raw fundamental data on tooth shape requires complex equipment and techniques. An online database of 3D teeth models is therefore indispensable. We aimed to explore the basic methodology for constructing 3D teeth models, with application for data sharing. Geometric information on the human permanent upper left incisor was obtained using micro-computed tomography (micro-CT). Enamel, dentine, and pulp were segmented by thresholding of different gray-scale intensities. Segmented data were separately exported in STereo-Lithography Interface Format (STL). STL data were converted to Wavefront OBJ (OBJect), as many 3D computer graphics programs support the Wavefront OBJ format. Data were also applied to Quick Time Virtual Reality (QTVR) format, which allows the image to be viewed from any direction. In addition to Wavefront OBJ and QTVR data, the original CT series were provided as 16-bit Tag Image File Format (TIFF) images on the website. In conclusion, 3D teeth models were constructed in general-purpose data formats, using micro-CT and commercially available programs. Teeth models that can be used widely would benefit all those who study dental morphology.

Advanced Computed-Tomography Inspection System

NASA Technical Reports Server (NTRS)

Harris, Lowell D.; Gupta, Nand K.; Smith, Charles R.; Bernardi, Richard T.; Moore, John F.; Hediger, Lisa

1993-01-01

Advanced Computed Tomography Inspection System (ACTIS) is computed-tomography x-ray apparatus revealing internal structures of objects in wide range of sizes and materials. Three x-ray sources and adjustable scan geometry gives system unprecedented versatility. Gantry contains translation and rotation mechanisms scanning x-ray beam through object inspected. Distance between source and detector towers varied to suit object. System used in such diverse applications as development of new materials, refinement of manufacturing processes, and inspection of components.

Usefulness of Tc99m-mebrofenin Hepatobiliary Scintigraphy and Single Photon Emission Computed Tomography/Computed Tomography in the Diagnosis of Bronchobiliary Fistula.

PubMed

Parghane, Rahul Vithalrao; Phulsunga, Rohit Kumar; Gupta, Rajesh; Basher, Rajender Kumar; Bhattacharya, Anish; Mittal, Bhagwant Rai

2017-01-01

Bronchobiliary fistula (BBF), a rare complication of liver disease, is an abnormal communication between the biliary tract and bronchial tree. BBF may occur as a consequence of local liver infections such as hydatid or amebic disease, pyogenic liver abscess or trauma to the liver, obstruction of biliary tract, and tumor. As such management of liver disease with BBF is very difficult and often associated with a high rate of morbidity and mortality. Therefore, timely diagnosis of BBF is imperative. Hepatobiliary scintigraphy along with hybrid single photon emission computed tomography/computed tomography using Tc99m-mebrofenin is a very useful noninvasive imaging modality, in the diagnosis of BBF.

Usefulness of Tc99m-mebrofenin Hepatobiliary Scintigraphy and Single Photon Emission Computed Tomography/Computed Tomography in the Diagnosis of Bronchobiliary Fistula

PubMed Central

Parghane, Rahul Vithalrao; Phulsunga, Rohit Kumar; Gupta, Rajesh; Basher, Rajender Kumar; Bhattacharya, Anish; Mittal, Bhagwant Rai

2017-01-01

Bronchobiliary fistula (BBF), a rare complication of liver disease, is an abnormal communication between the biliary tract and bronchial tree. BBF may occur as a consequence of local liver infections such as hydatid or amebic disease, pyogenic liver abscess or trauma to the liver, obstruction of biliary tract, and tumor. As such management of liver disease with BBF is very difficult and often associated with a high rate of morbidity and mortality. Therefore, timely diagnosis of BBF is imperative. Hepatobiliary scintigraphy along with hybrid single photon emission computed tomography/computed tomography using Tc99m-mebrofenin is a very useful noninvasive imaging modality, in the diagnosis of BBF. PMID:29033682

Weightbearing Computed Tomography of the Foot and Ankle: Emerging Technology Topical Review.

PubMed

Barg, Alexej; Bailey, Travis; Richter, Martinus; de Cesar Netto, Cesar; Lintz, François; Burssens, Arne; Phisitkul, Phinit; Hanrahan, Christopher J; Saltzman, Charles L

2018-03-01

In the last decade, cone-beam computed tomography technology with improved designs allowing flexible gantry movements has allowed both supine and standing weight-bearing imaging of the lower extremity. There is an increasing amount of literature describing the use of weightbearing computed tomography in patients with foot and ankle disorders. To date, there is no review article summarizing this imaging modality in the foot and ankle. Therefore, we performed a systematic literature review of relevant clinical studies targeting the use of weightbearing computed tomography in diagnosis of patients with foot and ankle disorders. Furthermore, this review aims to offer insight to those with interest in considering possible future research opportunities with use of this technology. Level V, expert opinion.

Sheep as a large animal model for middle and inner ear implantable hearing devices: a feasibility study in cadavers.

PubMed

Schnabl, Johannes; Glueckert, Rudolf; Feuchtner, Gudrun; Recheis, Wolfgang; Potrusil, Thomas; Kuhn, Volker; Wolf-Magele, Astrid; Riechelmann, Herbert; Sprinzl, Georg M

2012-04-01

Currently, no large animal model exists for surgical-experimental exploratory analysis of implantable hearing devices. In a histomorphometric study, we sought to investigate whether sheep or pig cochleae are suitable for this purpose and whether device implantation is feasible. Skulls of pig and sheep cadavers were examined using high-resolution 128-slice computed tomography (CT) to study anatomic relationships. A cochlear implant and an active middle ear implant could be successfully implanted into the sheep's inner and middle ear, respectively. Correct device placement was verified by CT and histology. The cochlear anatomy of the sheep was further studied by micro-CT and histology. Our investigations indicate that the sheep is a suitable animal model for implantation of implantable hearing devices. The implantation of the devices was successfully performed by access through a mastoidectomy. The histologic, morphologic, and micro-CT study of the sheep cochlea showed that it is highly similar to the human cochlea. The temporal bone of the pig was not suitable for these microsurgical procedures because the middle and inner ear were not accessible owing to distinct soft and fatty tissue coverage of the mastoid. The sheep is an appropriate large animal model for experimental studies with implantable hearing devices, whereas the pig is not.

Long-term evaluation of a new ventriculoperitoneal shunt valve system in a dog.

PubMed

Filgueiras, Richard da Rocha; Martins, Christine de Souza; de Almeida, Ricardo Miyasaka; Silva, Rosana Marques; da Rocha, Martha de Souza Teixeira; Firmino, Fernanda de Paula; Maguilnik, Samara; Medeiros, Luíza Quintão

2009-12-01

To report on the use of a new ventriculoperitoneal shunt (VPS) valve system utilized in a dog with hydrocephalus and to describe the clinical course over 20 months after implantation. A 3-month-old female Lhasa Apso dog was presented with lateral strabismus, domed calvarium, and visual deficits. A lateral skull radiograph revealed a persistent fontanelle. Transfontanellar ultrasonographic examination and computed tomographic examination showed excessive accumulation of fluid within the ventricles. The owner had observed symptoms as early as 1 month after birth, suggesting congenital hydrocephalus. A VPS with a new valve system that inhibits cerebrospinal fluid overdrainage and obstruction of the catheter was implanted. The dog showed clinical improvement 48 hours after the procedure. Twenty days after shunt implantation, another computed tomography scan was performed that showed reduction in ventricle size. The evaluation of VPS patency was carried out 20 months after surgery and demonstrated that the system was working properly without obstruction. There are reports in the literature describing the use of several devices to perform VPS in dogs. A new device not previously described in the veterinary literature was used in this case report, and according to the manufacturer's description, this device inhibits proteinaceous build-up, which is usually responsible for subsequent catheter obstructions.

[Advance in imaging spectropolarimeter].

PubMed

Wang, Xin-quan; Xiangli, Bin; Huang, Min; Hu, Liang; Zhou, Jin-song; Jing, Juan-juan

2011-07-01

Imaging spectropolarimeter (ISP) is a type of novel photoelectric sensor which integrated the functions of imaging, spectrometry and polarimetry. In the present paper, the concept of the ISP is introduced, and the advances in ISP at home and abroad in recent years is reviewed. The principles of ISPs based on novel devices, such as acousto-optic tunable filter (AOTF) and liquid crystal tunable filter (LCTF), are illustrated. In addition, the principles of ISPs developed by adding polarized components to the dispersing-type imaging spectrometer, spatially modulated Fourier transform imaging spectrometer, and computer tomography imaging spectrometer are introduced. Moreover, the trends of ISP are discussed too.

European Society of Endodontology position statement: the use of CBCT in endodontics.

PubMed

Patel, S; Durack, C; Abella, F; Roig, M; Shemesh, H; Lambrechts, P; Lemberg, K

2014-06-01

This Position Statement represents a consensus of an expert committee convened by the European Society of Endodontology (ESE) on the use of Cone Beam Computed Tomography (CBCT). The statement is based on the current scientific evidence, and provides the clinician with evidence-based criteria on when to use CBCT in Endodontics. Given the dynamic and changing nature of research, development of new devices and clinical practice relating to CBCT, this Position Statement will be updated within 3 years, or before that time should new evidence become available. © 2014 International Endodontic Journal. Published by John Wiley & Sons Ltd.

Potential techniques for non-destructive evaluation of cable materials

NASA Astrophysics Data System (ADS)

Gillen, Kenneth T.; Clough, Roger L.; Mattson, Bengt; Stenberg, Bengt; Oestman, Erik

This paper describes the connection between mechanical degradation of common cable materials, in radiation and elevated temperature environments, and density increases caused by the oxidation which leads to this degradation. Two techniques based on density changes are suggested as potential non-destructive evaluation (NDE) procedures which may be applicable to monitoring the mechanical condition of cable materials in power plant environments. The first technique is direct measurement of density changes, via a density gradient column, using small shavings removed from the surface of cable jackets at selected locations. The second technique is computed X-ray tomography, utilizing a portable scanning device.

Evaluating the risk of appendiceal perforation when using ultrasound as the initial diagnostic imaging modality in children with suspected appendicitis.

PubMed

Alerhand, Stephen; Meltzer, James; Tay, Ee Tein

2017-08-01

Ultrasound scan has gained attention for diagnosing appendicitis due to its avoidance of ionizing radiation. However, studies show that ultrasound scan carries inferior sensitivity to computed tomography scan. A non-diagnostic ultrasound scan could increase the time to diagnosis and appendicectomy, particularly if follow-up computed tomography scan is needed. Some studies suggest that delaying appendicectomy increases the risk of perforation. To investigate the risk of appendiceal perforation when using ultrasound scan as the initial diagnostic imaging modality in children with suspected appendicitis. We retrospectively reviewed 1411 charts of children ≤17 years old diagnosed with appendicitis at two urban academic medical centers. Patients who underwent ultrasound scan first were compared to those who underwent computed tomography scan first. In the sub-group analysis, patients who only received ultrasound scan were compared to those who received initial ultrasound scan followed by computed tomography scan. Main outcome measures were appendiceal perforation rate and time from triage to appendicectomy. In 720 children eligible for analysis, there was no significant difference in perforation rate between those who had initial ultrasound scan and those who had initial computed tomography scan (7.3% vs. 8.9%, p = 0.44), nor in those who had ultrasound scan only and those who had initial ultrasound scan followed by computed tomography scan (8.0% vs. 5.6%, p = 0.42). Those patients who had ultrasound scan first had a shorter triage-to-incision time than those who had computed tomography scan first (9.2 (IQR: 5.9, 14.0) vs. 10.2 (IQR: 7.3, 14.3) hours, p = 0.03), whereas those who had ultrasound scan followed by computed tomography scan took longer than those who had ultrasound scan only (7.8 (IQR: 5.3, 11.6) vs. 15.1 (IQR: 10.6, 20.6), p < 0.001). Children < 12 years old receiving ultrasound scan first had lower perforation rate (p = 0.01) and shorter triage-to-incision time (p = 0.003). Children with suspected appendicitis receiving ultrasound scan as the initial diagnostic imaging modality do not have increased risk of perforation compared to those receiving computed tomography scan first. We recommend that children <12 years of age receive ultrasound scan first.

Neural networks for calibration tomography

NASA Technical Reports Server (NTRS)

Decker, Arthur

1993-01-01

Artificial neural networks are suitable for performing pattern-to-pattern calibrations. These calibrations are potentially useful for facilities operations in aeronautics, the control of optical alignment, and the like. Computed tomography is compared with neural net calibration tomography for estimating density from its x-ray transform. X-ray transforms are measured, for example, in diffuse-illumination, holographic interferometry of fluids. Computed tomography and neural net calibration tomography are shown to have comparable performance for a 10 degree viewing cone and 29 interferograms within that cone. The system of tomography discussed is proposed as a relevant test of neural networks and other parallel processors intended for using flow visualization data.

Lap-Protector and Circular Stapler Are Useful in Cystogastrostomy for Large Pancreatic Pseudocyst with Severe Infection

PubMed Central

Kadowaki, Yoshihiko; Kurokawa, Takefumi; Tamura, Ryuji; Okamoto, Takahiro; Ishido, Nobuhiro; Mori, Takashi

2010-01-01

Lap-Protector, which is an abdominal wall sealing device, is usually used for wound protection from implantation of malignant cells or pyogenic fluid. A circular stapler is a common easy-to-use device for anastomosis of the digestive tract. We report the case of an infected pancreatic pseudocyst which was treated by surgical procedure using these useful devices. A 69-year-old man was followed up in our hospital after severe acute pancreatitis. He had undergone drainage surgeries twice for intractable pancreatic abscess followed by severe acute pancreatitis. He was admitted to our hospital complaining of loss of appetite, hiccups, and high fever. Computed tomography of the abdomen revealed an infected pancreatic pseudocyst which compressed the gastric wall. Internal drainage into the stomach was performed using Lap-Protector and circular stapler. The patient recovered uneventfully. Recently many endoscopic or laparoscopic procedures in cystogastrostomy are reported; however, a conventional open surgical approach is also important. This easy method may be useful for operative cystogastrostomy. PMID:20805947

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

Use of cone beam computed tomography in implant dentistry: current concepts, indications and limitations for clinical practice and research.

PubMed

Bornstein, Michael M; Horner, Keith; Jacobs, Reinhilde

2017-02-01

Diagnostic radiology is an essential component of treatment planning in the field of implant dentistry. This narrative review will present current concepts for the use of cone beam computed tomography imaging, before and after implant placement, in daily clinical practice and research. Guidelines for the selection of three-dimensional imaging will be discussed, and limitations will be highlighted. Current concepts of radiation dose optimization, including novel imaging modalities using low-dose protocols, will be presented. For preoperative cross-sectional imaging, data are still not available which demonstrate that cone beam computed tomography results in fewer intraoperative complications such as nerve damage or bleeding incidents, or that implants inserted using preoperative cone beam computed tomography data sets for planning purposes will exhibit higher survival or success rates. The use of cone beam computed tomography following the insertion of dental implants should be restricted to specific postoperative complications, such as damage of neurovascular structures or postoperative infections in relation to the maxillary sinus. Regarding peri-implantitis, the diagnosis and severity of the disease should be evaluated primarily based on clinical parameters and on radiological findings based on periapical radiographs (two dimensional). The use of cone beam computed tomography scans in clinical research might not yield any evident beneficial effect for the patient included. As many of the cone beam computed tomography scans performed for research have no direct therapeutic consequence, dose optimization measures should be implemented by using appropriate exposure parameters and by reducing the field of view to the actual region of interest. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

How reliably can computed tomography predict thyroid invasion prior to laryngectomy?

PubMed

Harris, Andrew S; Passant, Carl D; Ingrams, Duncan R

2018-05-01

There is little evidence to support the removal of thyroid tissue during total laryngectomy. Although oncological control of the tumor is the priority, thyroidectomy can lead to hypothyroidism and hypoparathyroidism. This study aimed to test the usefulness of preoperative computed tomography in predicting histological invasion of the thyroid. Ambispective cohort study. All patients undergoing total laryngectomy for squamous cell carcinoma at one center from 2006 to 2016 were included. Data were recorded prospectively as part of the patients' standard care, but were collated retrospectively, giving this study an ambispective design. The histology report for thyroid invasion was taken as the gold standard. The computed tomography report was categorized by invasion of tumor into intralaryngeal, laryngeal cartilage involvement, and extralaryngeal tissues. Seventy-nine patients were included. Nine patients had thyroid involvement on histology, translating to an incidence of 11.29% in this population. The positive predictive value for cartilage involvement on computed tomography for thyroid invasion was 52.9% (95% confidence interval [CI]: 28.5%-76.1%) and the negative predictive value was 100% (95% CI: 92.7%-100%).The positive predictive value for extralaryngeal spread on computed tomography for thyroid involvement was 100% (95% CI: 62.9%-100%), and the negative predictive value was also 100% (95% CI: 93.5%-100%). This study has shown that preoperative computed tomography is an effective method of ruling out thyroid gland invasion. The absence of extralaryngeal spread on computed tomography has been shown to be the most useful finding, with a high negative predictive value and a narrow 95% CI. 4. Laryngoscope, 128:1099-1102, 2018. © 2017 The American Laryngological, Rhinological and Otological Society, Inc.

Diverticular Disease of the Colon: News From Imaging.

PubMed

Flor, Nicola; Soldi, Simone; Zanchetta, Edoardo; Sbaraini, Sara; Pesapane, Filippo

2016-10-01

Different scenarios embrace computed tomography imaging and diverticula, including asymptomatic (diverticulosis) and symptomatic patients (acute diverticulitis, follow-up of acute diverticulitis, chronic diverticulitis). If the role of computed tomography is validated and widely supported by evidence in case of acute diverticulitis, this is not the case of patients in their follow-up for acute diverticulitis or with symptoms related to diverticula, but without acute inflammation. In these settings, computed tomography colonography is gaining consensus as the preferred radiologic test.

Plain X-ray, computed tomography and magnetic resonance imaging findings of telangiectatic osteosarcoma: a case report.

PubMed

Skiadas, Vasilios; Koutoulidis, Vasilios; Koureas, Andreas; Moulopoulos, Lia; Gouliamos, Athanasios

2009-09-16

An 18-year-old male patient presented with chronic nonspecific pain of three months located at his left proximal tibia. The patient was admitted to our department for plain X-ray, computed tomography and magnetic resonance imaging examination. Plain X-ray and computed tomography revealed a geographic lytic lesion at the medial aspect of the proximal tibia. Biopsy of the lesion showed telangiectatic osteosarcoma. Image findings of all modalities are presented.

Advances in equine computed tomography and use of contrast media.

PubMed

Puchalski, Sarah M

2012-12-01

Advances in equine computed tomography have been made as a result of improvements in software and hardware and an increasing body of knowledge. Contrast media can be administered intravascularly or intrathecally. Contrast media is useful to differentiate between tissues of similar density. Equine computed tomography can be used for many different clinical conditions, including lameness diagnosis, fracture identification and characterization, preoperative planning, and characterization of skull diseases. Copyright © 2012 Elsevier Inc. All rights reserved.

[The radiologist physician in major trauma evaluation].

PubMed

Motta-Ramírez, Gaspar Alberto

2016-01-01

Trauma is the most common cause of death in young adults. A multidisciplinary trauma team consists of at least a surgical team, an anesthesiology team, radiologic team, and an emergency department team. Recognize the integration of multidisciplinary medical team in managing the trauma patient and which must include the radiologist physician responsible for the institutional approach to the systematization of the trauma patient regarding any radiological and imaging study with emphasis on the FAST (del inglés, Focused Assessment with Sonography in Trauma)/USTA, Whole body computed tomography. Ultrasound is a cross-sectional method available for use in patients with major trauma. Whole-body multidetector computed tomography became the imaging modality of choice in the late 1990s. In patients with major trauma, examination FAST often is the initial imaging examination, extended to extraabdominal regions. Patients who have multitrauma from blunt mechanisms often require multiple diagnostic examinations, including Computed Tomography imaging of the torso as well as abdominopelvic Computed Tomography angiography. Multiphasic Whole-body trauma imaging is feasible, helps detect clinically relevant vascular injuries, and results in diagnostic image quality in the majority of patients. Computed Tomography has gained importance in the early diagnostic phase of trauma care in the emergency room. With a single continuous acquisition, whole-body computed tomography angiography is able to demonstrate all potentially injured organs, as well as vascular and bone structures, from the circle of Willis to the symphysis pubis.

Biologically relevant photoacoustic imaging phantoms with tunable optical and acoustic properties

PubMed Central

Vogt, William C.; Jia, Congxian; Wear, Keith A.; Garra, Brian S.; Joshua Pfefer, T.

2016-01-01

Abstract. Established medical imaging technologies such as magnetic resonance imaging and computed tomography rely on well-validated tissue-simulating phantoms for standardized testing of device image quality. The availability of high-quality phantoms for optical-acoustic diagnostics such as photoacoustic tomography (PAT) will facilitate standardization and clinical translation of these emerging approaches. Materials used in prior PAT phantoms do not provide a suitable combination of long-term stability and realistic acoustic and optical properties. Therefore, we have investigated the use of custom polyvinyl chloride plastisol (PVCP) formulations for imaging phantoms and identified a dual-plasticizer approach that provides biologically relevant ranges of relevant properties. Speed of sound and acoustic attenuation were determined over a frequency range of 4 to 9 MHz and optical absorption and scattering over a wavelength range of 400 to 1100 nm. We present characterization of several PVCP formulations, including one designed to mimic breast tissue. This material is used to construct a phantom comprised of an array of cylindrical, hemoglobin-filled inclusions for evaluation of penetration depth. Measurements with a custom near-infrared PAT imager provide quantitative and qualitative comparisons of phantom and tissue images. Results indicate that our PVCP material is uniquely suitable for PAT system image quality evaluation and may provide a practical tool for device validation and intercomparison. PMID:26886681

System theory in medical diagnostic devices: an overview.

PubMed

Baura, Gail D

2006-01-01

Medical diagnostics refers to testing conducted either in vitro or in vivo to provide critical health care information for risk assessment, early diagnosis, treatment, or disease management. Typical in vivo diagnostic tests include the computed tomography scan, magnetic resonance imaging, and blood pressure screening. Typical in vitro diagnostic tests include cholesterol, Papanicolaou smear, and conventional glucose monitoring tests. Historically, devices associated with both types of diagnostics have used heuristic curve fitting during signal analysis. However, since the early 1990s, a few enterprising engineers and physicians have used system theory to improve their core processing for feature detection and system identification. Current applications include automated Pap smear screening for detection of cervical cancer and diagnosis of Alzheimer's disease. Future applications, such as disease prediction before symptom onset and drug treatment customization, have been catalyzed by the Human Genome Project.

Development of computational small animal models and their applications in preclinical imaging and therapy research.

PubMed

Xie, Tianwu; Zaidi, Habib

2016-01-01

The development of multimodality preclinical imaging techniques and the rapid growth of realistic computer simulation tools have promoted the construction and application of computational laboratory animal models in preclinical research. Since the early 1990s, over 120 realistic computational animal models have been reported in the literature and used as surrogates to characterize the anatomy of actual animals for the simulation of preclinical studies involving the use of bioluminescence tomography, fluorescence molecular tomography, positron emission tomography, single-photon emission computed tomography, microcomputed tomography, magnetic resonance imaging, and optical imaging. Other applications include electromagnetic field simulation, ionizing and nonionizing radiation dosimetry, and the development and evaluation of new methodologies for multimodality image coregistration, segmentation, and reconstruction of small animal images. This paper provides a comprehensive review of the history and fundamental technologies used for the development of computational small animal models with a particular focus on their application in preclinical imaging as well as nonionizing and ionizing radiation dosimetry calculations. An overview of the overall process involved in the design of these models, including the fundamental elements used for the construction of different types of computational models, the identification of original anatomical data, the simulation tools used for solving various computational problems, and the applications of computational animal models in preclinical research. The authors also analyze the characteristics of categories of computational models (stylized, voxel-based, and boundary representation) and discuss the technical challenges faced at the present time as well as research needs in the future.

High-resolution PET [Positron Emission Tomography] for Medical Science Studies

DOE R&D Accomplishments Database

Budinger, T. F.; Derenzo, S. E.; Huesman, R. H.; Jagust, W. J.; Valk, P. E.

1989-09-01

One of the unexpected fruits of basic physics research and the computer revolution is the noninvasive imaging power available to today's physician. Technologies that were strictly the province of research scientists only a decade or two ago now serve as the foundations for such standard diagnostic tools as x-ray computer tomography (CT), magnetic resonance imaging (MRI), magnetic resonance spectroscopy (MRS), ultrasound, single photon emission computed tomography (SPECT), and positron emission tomography (PET). Furthermore, prompted by the needs of both the practicing physician and the clinical researcher, efforts to improve these technologies continue. This booklet endeavors to describe the advantages of achieving high resolution in PET imaging.

Wireless, Web-Based Interactive Control of Optical Coherence Tomography with Mobile Devices

PubMed Central

Mehta, Rajvi; Nankivil, Derek; Zielinski, David J.; Waterman, Gar; Keller, Brenton; Limkakeng, Alexander T.; Kopper, Regis; Izatt, Joseph A.; Kuo, Anthony N.

2017-01-01

Purpose Optical coherence tomography (OCT) is widely used in ophthalmology clinics and has potential for more general medical settings and remote diagnostics. In anticipation of remote applications, we developed wireless interactive control of an OCT system using mobile devices. Methods A web-based user interface (WebUI) was developed to interact with a handheld OCT system. The WebUI consisted of key OCT displays and controls ported to a webpage using HTML and JavaScript. Client–server relationships were created between the WebUI and the OCT system computer. The WebUI was accessed on a cellular phone mounted to the handheld OCT probe to wirelessly control the OCT system. Twenty subjects were imaged using the WebUI to assess the system. System latency was measured using different connection types (wireless 802.11n only, wireless to remote virtual private network [VPN], and cellular). Results Using a cellular phone, the WebUI was successfully used to capture posterior eye OCT images in all subjects. Simultaneous interactivity by a remote user on a laptop was also demonstrated. On average, use of the WebUI added only 58, 95, and 170 ms to the system latency using wireless only, wireless to VPN, and cellular connections, respectively. Qualitatively, operator usage was not affected. Conclusions Using a WebUI, we demonstrated wireless and remote control of an OCT system with mobile devices. Translational Relevance The web and open source software tools used in this project make it possible for any mobile device to potentially control an OCT system through a WebUI. This platform can be a basis for remote, teleophthalmology applications using OCT. PMID:28138415

Use of Noncontrast Computed Tomography and Computed Tomographic Perfusion in Predicting Intracerebral Hemorrhage After Intravenous Alteplase Therapy.

PubMed

Batchelor, Connor; Pordeli, Pooneh; d'Esterre, Christopher D; Najm, Mohamed; Al-Ajlan, Fahad S; Boesen, Mari E; McDougall, Connor; Hur, Lisa; Fainardi, Enrico; Shankar, Jai Jai Shiva; Rubiera, Marta; Khaw, Alexander V; Hill, Michael D; Demchuk, Andrew M; Sajobi, Tolulope T; Goyal, Mayank; Lee, Ting-Yim; Aviv, Richard I; Menon, Bijoy K

2017-06-01

Intracerebral hemorrhage is a feared complication of intravenous alteplase therapy in patients with acute ischemic stroke. We explore the use of multimodal computed tomography in predicting this complication. All patients were administered intravenous alteplase with/without intra-arterial therapy. An age- and sex-matched case-control design with classic and conditional logistic regression techniques was chosen for analyses. Outcome was parenchymal hemorrhage on 24- to 48-hour imaging. Exposure variables were imaging (noncontrast computed tomography hypoattenuation degree, relative volume of very low cerebral blood volume, relative volume of cerebral blood flow ≤7 mL/min·per 100 g, relative volume of T max ≥16 s with all volumes standardized to z axis coverage, mean permeability surface area product values within T max ≥8 s volume, and mean permeability surface area product values within ipsilesional hemisphere) and clinical variables (NIHSS [National Institutes of Health Stroke Scale], onset to imaging time, baseline systolic blood pressure, blood glucose, serum creatinine, treatment type, and reperfusion status). One-hundred eighteen subjects (22 patients with parenchymal hemorrhage versus 96 without, median baseline NIHSS score of 15) were included in the final analysis. In multivariable regression, noncontrast computed tomography hypoattenuation grade ( P <0.006) and computerized tomography perfusion white matter relative volume of very low cerebral blood volume ( P =0.04) were the only significant variables associated with parenchymal hemorrhage on follow-up imaging (area under the curve, 0.73; 95% confidence interval, 0.63-0.83). Interrater reliability for noncontrast computed tomography hypoattenuation grade was moderate (κ=0.6). Baseline hypoattenuation on noncontrast computed tomography and very low cerebral blood volume on computerized tomography perfusion are associated with development of parenchymal hemorrhage in patients with acute ischemic stroke receiving intravenous alteplase. © 2017 American Heart Association, Inc.

Use of radiography, computed tomography and magnetic resonance imaging for evaluation of navicular syndrome in the horse.

PubMed

Widmer, W R; Buckwalter, K A; Fessler, J F; Hill, M A; VanSickle, D C; Ivancevich, S

2000-01-01

Radiographic evaluation of navicular syndrome is problematic because of its inconsistent correlation with clinical signs. Scintigraphy often yields false positive and false negative results and diagnostic ultrasound is of limited value. Therefore, we assessed the use of computed tomography and magnetic resonance imaging in a horse with clinical and radiographic signs of navicular syndrome. Cadaver specimens were examined with spiral computed tomographic and high-field magnetic resonance scanners and images were correlated with pathologic findings. Radiographic changes consisted of bony remodeling, which included altered synovial fossae, increased medullary opacity, cyst formation and shape change. These osseous changes were more striking and more numerous on computed tomographic and magnetic resonance images. They were most clearly defined with computed tomography. Many osseous changes seen with computed tomography and magnetic resonance imaging were not radiographically evident. Histologically confirmed soft tissue alterations of the deep digital flexor tendon, impar ligament and marrow were identified with magnetic resonance imaging, but not with conventional radiography. Because of their multiplanar capability and tomographic nature, computed tomography and magnetic resonance imaging surpass conventional radiography for navicular imaging, facilitating earlier, more accurate diagnosis. Current advances in imaging technology should make these imaging modalities available to equine practitioners in the future.

Quantitative Comparison of Virtual Monochromatic Images of Dual Energy Computed Tomography Systems: Beam Hardening Artifact Correction and Variance in Computed Tomography Numbers: A Phantom Study.

PubMed

Wu, Rongli; Watanabe, Yoshiyuki; Satoh, Kazuhiko; Liao, Yen-Peng; Takahashi, Hiroto; Tanaka, Hisashi; Tomiyama, Noriyuki

2018-05-21

The aim of this study was to quantitatively compare the reduction in beam hardening artifact (BHA) and variance in computed tomography (CT) numbers of virtual monochromatic energy (VME) images obtained with 3 dual-energy computed tomography (DECT) systems at a given radiation dose. Five different iodine concentrations were scanned using dual-energy and single-energy (120 kVp) modes. The BHA and CT number variance were evaluated. For higher iodine concentrations, 40 and 80 mgI/mL, BHA on VME imaging was significantly decreased when the energy was higher than 50 keV (P = 0.003) and 60 keV (P < 0.001) for GE, higher than 80 keV (P < 0.001) and 70 keV (P = 0.002) for Siemens, and higher than 40 keV (P < 0.001) and 60 keV (P < 0.001) for Toshiba, compared with single-energy CT imaging. Virtual monochromatic energy imaging can decrease BHA and improve CT number accuracy in different dual-energy computed tomography systems, depending on energy levels and iodine concentrations.

Virtopsy: postmortem imaging of laryngeal foreign bodies.

PubMed

Oesterhelweg, Lars; Bolliger, Stephan A; Thali, Michael J; Ross, Steffen

2009-05-01

Death from corpora aliena in the larynx is a well-known entity in forensic pathology. The correct diagnosis of this cause of death is difficult without an autopsy, and misdiagnoses by external examination alone are common. To determine the postmortem usefulness of modern imaging techniques in the diagnosis of foreign bodies in the larynx, multislice computed tomography, magnetic resonance imaging, and postmortem full-body computed tomography-angiography were performed. Three decedents with a suspected foreign body in the larynx underwent the 3 different imaging techniques before medicolegal autopsy. Multislice computed tomography has a high diagnostic value in the noninvasive localization of a foreign body and abnormalities in the larynx. The differentiation between neoplasm or soft foreign bodies (eg, food) is possible, but difficult, by unenhanced multislice computed tomography. By magnetic resonance imaging, the discrimination of the soft tissue structures and soft foreign bodies is much easier. In addition to the postmortem multislice computed tomography, the combination with postmortem angiography will increase the diagnostic value. Postmortem, cross-sectional imaging methods are highly valuable procedures for the noninvasive detection of corpora aliena in the larynx.

Leg CT scan

MedlinePlus

CAT scan - leg; Computed axial tomography scan - leg; Computed tomography scan - leg; CT scan - leg ... CT scan makes detailed pictures of the body very quickly. The test may help look for: An abscess ...

Arm CT scan

MedlinePlus

CAT scan - arm; Computed axial tomography scan - arm; Computed tomography scan - arm; CT scan - arm ... Healing problems or scar tissue following surgery A CT scan may also be used to guide a surgeon ...

USE OF COMPUTED TOMOGRAPHY FOR INVESTIGATION OF HEPATIC LIPIDOSIS IN CAPTIVE CHELONOIDIS CARBONARIA (SPIX, 1824).

PubMed

Marchiori, Adriano; da Silva, Ieverton Cleiton Correia; de Albuquerque Bonelli, Marília; de Albuquerque Zanotti, Luciana Carla Rameh; Siqueira, Daniel B; Zanotti, Alexandre Pinheiro; Costa, Fabiano Séllos

2015-06-01

Computed tomography is a sensitive and highly applicable technique for determining the degree of radiographic attenuation of the hepatic parenchyma. Radiodensity measurements of the liver can help in the diagnosis of hepatic lipidosis in humans and animals. The objective was to investigate the presence of hepatic lipidosis in captive red-footed tortoises (Chelonoidis carbonaria) using computed tomography. Computed tomography was performed in 10 male red-footed tortoises. Mean radiographic attenuation values for the hepatic parenchyma were 11.2±3.0 Hounsfield units (HU). Seven red-footed tortoises had values lower than 20 HU, which is compatible with C. carbonaria hepatic lipidosis. These results allowed an early diagnosis of the hepatic changes and suggested corrective measures regarding feeding and management protocols.

Multidetector Computed Tomography for Congenital Anomalies of the Aortic Arch: Vascular Rings.

PubMed

García-Guereta, Luis; García-Cerro, Estefanía; Bret-Zurita, Montserrat

2016-07-01

The development of multidetector computed tomography has triggered a revolution in the study of the aorta and other large vessels and has replaced angiography in the diagnosis of congenital anomalies of the aortic arch, particularly vascular rings. The major advantage of multidetector computed tomography is that it permits clear 3-dimensional assessment of not only vascular structures, but also airway and esophageal compression. The current update aims to summarize the embryonic development of the aortic arch and the developmental anomalies leading to vascular ring formation and to discuss the current diagnostic and therapeutic role of multidetector computed tomography in this field. Copyright © 2016 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

Comprehensive Digital Imaging Network Project At Georgetown University Hospital

NASA Astrophysics Data System (ADS)

Mun, Seong K.; Stauffer, Douglas; Zeman, Robert; Benson, Harold; Wang, Paul; Allman, Robert

1987-10-01

The radiology practice is going through rapid changes due to the introduction of state-of-the-art computed based technologies. For the last twenty years we have witnessed the introduction of many new medical diagnostic imaging systems such as x-ray computed tomo-graphy, digital subtraction angiography (DSA), computerized nuclear medicine, single pho-ton emission computed tomography (SPECT), positron emission tomography (PET) and more re-cently, computerized digital radiography and nuclear magnetic resonance imaging (MRI). Other than the imaging systems, there has been a steady introduction of computed based information systems for radiology departments and hospitals.

Utility of three-dimensional and multiplanar reformatted computed tomography for evaluation of pediatric congenital spine abnormalities.

PubMed

Newton, Peter O; Hahn, Gregory W; Fricka, Kevin B; Wenger, Dennis R

2002-04-15

A retrospective radiographic review of 31 patients with congenital spine abnormalities who underwent conventional radiography and advanced imaging studies was conducted. To analyze the utility of three-dimensional computed tomography with multiplanar reformatted images for congenital spine anomalies, as compared with plain radiographs and axial two-dimensional computed tomography imaging. Conventional radiographic imaging for congenital spine disorders often are difficult to interpret because of the patient's small size, the complexity of the disorder, a deformity not in the plane of the radiographs, superimposed structures, and difficulty in forming a mental three-dimensional image. Multiplanar reformatted and three-dimensional computed tomographic imaging offers many potential advantages for defining congenital spine anomalies including visualization of the deformity in any plane, from any angle, with the overlying structures subtracted. The imaging studies of patients who had undergone a three-dimensional computed tomography for congenital deformities of the spine between 1992 and 1998 were reviewed (31 cases). All plain radiographs and axial two-dimensional computed tomography images performed before the three-dimensional computed tomography were reviewed and the findings documented. This was repeated for the three-dimensional reconstructions and, when available, the multiplanar reformatted images (15 cases). In each case, the utility of the advanced imaging was graded as one of the following: Grade A (substantial new information obtained), Grade B (confirmatory with improved visualization and understanding of the deformity), and Grade C (no added useful information obtained). In 17 of 31 cases, the multiplanar reformatted and three-dimensional images allowed identification of unrecognized malformations. In nine additional cases, the advanced imaging was helpful in better visualizing and understanding previously identified deformities. In five cases, no new information was gained. The standard and curved multiplanar reformatted images were best for defining the occiput-C1-C2 anatomy and the extent of segmentation defects. The curved multiplanar reformatted images were especially helpful in keeping the spine from "coming in" and "going out" of the plane of the image when there was significant spine deformity in the sagittal or coronal plane. The three-dimensional reconstructions proved valuable in defining failures of formation. Advanced computed tomography imaging (three-dimensional computed tomography and curved/standard multiplanar reformatted images) allows better definition of congenital spine anomalies. More than 50% of the cases showed additional abnormalities not appreciated on plain radiographs or axial two-dimensional computed tomography images. Curved multiplanar reformatted images allowed imaging in the coronal and sagittal planes of the entire deformity.

Heart CT scan

MedlinePlus

... Computed tomography scan - heart; Calcium scoring; Multi-detector CT scan - heart; Electron beam computed tomography - heart; Agatston ... table that slides into the center of the CT scanner. You will lie on your back with ...

Evaluation of 3D airway imaging of obstructive sleep apnea with cone-beam computed tomography.

PubMed

Ogawa, Takumi; Enciso, Reyes; Memon, Ahmed; Mah, James K; Clark, Glenn T

2005-01-01

This study evaluates the use of cone-beam Computer Tomography (CT) for imaging the upper airway structure of Obstructive Sleep Apnea (OSA) patients. The total airway volume and the anteroposterior dimension of oropharyngeal airway showed significant group differences between OSA and gender-matched controls, so if we increase sample size these measurements may distinguish the two groups. We demonstrate the utility of diagnosis of anatomy with the 3D airway imaging with cone-beam Computed Tomography.

Cone beam computed tomography in Endodontics - a review.

PubMed

Patel, S; Durack, C; Abella, F; Shemesh, H; Roig, M; Lemberg, K

2015-01-01

Cone beam computed tomography (CBCT) produces undistorted three-dimensional information of the maxillofacial skeleton, including the teeth and their surrounding tissues with a lower effective radiation dose than computed tomography. The aim of this paper is to: (i) review the current literature on the applications and limitations of CBCT; (ii) make recommendations for the use of CBCT in Endodontics; (iii) highlight areas of further research of CBCT in Endodontics. © 2014 International Endodontic Journal. Published by John Wiley & Sons Ltd.

White Paper of the Society of Computed Body Tomography and Magnetic Resonance on Dual-Energy CT, Part 1: Technology and Terminology.

PubMed

Siegel, Marilyn J; Kaza, Ravi K; Bolus, David N; Boll, Daniel T; Rofsky, Neil M; De Cecco, Carlo N; Foley, W Dennis; Morgan, Desiree E; Schoepf, U Joseph; Sahani, Dushyant V; Shuman, William P; Vrtiska, Terri J; Yeh, Benjamin M; Berland, Lincoln L

This is the first of a series of 4 white papers that represent Expert Consensus Documents developed by the Society of Computed Body Tomography and Magnetic Resonance through its task force on dual-energy computed tomography (DECT). This article, part 1, describes the fundamentals of the physical basis for DECT and the technology of DECT and proposes uniform nomenclature to account for differences in proprietary terms among manufacturers.

[Cardiac computed tomography: new applications of an evolving technique].

PubMed

Martín, María; Corros, Cecilia; Calvo, Juan; Mesa, Alicia; García-Campos, Ana; Rodríguez, María Luisa; Barreiro, Manuel; Rozado, José; Colunga, Santiago; de la Hera, Jesús M; Morís, César; Luyando, Luis H

2015-01-01

During the last years we have witnessed an increasing development of imaging techniques applied in Cardiology. Among them, cardiac computed tomography is an emerging and evolving technique. With the current possibility of very low radiation studies, the applications have expanded and go further coronariography In the present article we review the technical developments of cardiac computed tomography and its new applications. Copyright © 2014 Instituto Nacional de Cardiología Ignacio Chávez. Published by Masson Doyma México S.A. All rights reserved.

Plain X-ray, computed tomography and magnetic resonance imaging findings of telangiectatic osteosarcoma: a case report

PubMed Central

Koutoulidis, Vasilios; Koureas, Andreas; Moulopoulos, Lia; Gouliamos, Athanasios

2009-01-01

An 18-year-old male patient presented with chronic nonspecific pain of three months located at his left proximal tibia. The patient was admitted to our department for plain X-ray, computed tomography and magnetic resonance imaging examination. Plain X-ray and computed tomography revealed a geographic lytic lesion at the medial aspect of the proximal tibia. Biopsy of the lesion showed telangiectatic osteosarcoma. Image findings of all modalities are presented. PMID:19918488

Enabling Real-Time Volume Rendering of Functional Magnetic Resonance Imaging on an iOS Device.

PubMed

Holub, Joseph; Winer, Eliot

2017-12-01

Powerful non-invasive imaging technologies like computed tomography (CT), ultrasound, and magnetic resonance imaging (MRI) are used daily by medical professionals to diagnose and treat patients. While 2D slice viewers have long been the standard, many tools allowing 3D representations of digital medical data are now available. The newest imaging advancement, functional MRI (fMRI) technology, has changed medical imaging from viewing static to dynamic physiology (4D) over time, particularly to study brain activity. Add this to the rapid adoption of mobile devices for everyday work and the need to visualize fMRI data on tablets or smartphones arises. However, there are few mobile tools available to visualize 3D MRI data, let alone 4D fMRI data. Building volume rendering tools on mobile devices to visualize 3D and 4D medical data is challenging given the limited computational power of the devices. This paper describes research that explored the feasibility of performing real-time 3D and 4D volume raycasting on a tablet device. The prototype application was tested on a 9.7" iPad Pro using two different fMRI datasets of brain activity. The results show that mobile raycasting is able to achieve between 20 and 40 frames per second for traditional 3D datasets, depending on the sampling interval, and up to 9 frames per second for 4D data. While the prototype application did not always achieve true real-time interaction, these results clearly demonstrated that visualizing 3D and 4D digital medical data is feasible with a properly constructed software framework.

Accuracy and Precision of Radioactivity Quantification in Nuclear Medicine Images

PubMed Central

Frey, Eric C.; Humm, John L.; Ljungberg, Michael

2012-01-01

The ability to reliably quantify activity in nuclear medicine has a number of increasingly important applications. Dosimetry for targeted therapy treatment planning or for approval of new imaging agents requires accurate estimation of the activity in organs, tumors, or voxels at several imaging time points. Another important application is the use of quantitative metrics derived from images, such as the standard uptake value commonly used in positron emission tomography (PET), to diagnose and follow treatment of tumors. These measures require quantification of organ or tumor activities in nuclear medicine images. However, there are a number of physical, patient, and technical factors that limit the quantitative reliability of nuclear medicine images. There have been a large number of improvements in instrumentation, including the development of hybrid single-photon emission computed tomography/computed tomography and PET/computed tomography systems, and reconstruction methods, including the use of statistical iterative reconstruction methods, which have substantially improved the ability to obtain reliable quantitative information from planar, single-photon emission computed tomography, and PET images. PMID:22475429

Meaning of Interior Tomography

PubMed Central

Wang, Ge; Yu, Hengyong

2013-01-01

The classic imaging geometry for computed tomography is for collection of un-truncated projections and reconstruction of a global image, with the Fourier transform as the theoretical foundation that is intrinsically non-local. Recently, interior tomography research has led to theoretically exact relationships between localities in the projection and image spaces and practically promising reconstruction algorithms. Initially, interior tomography was developed for x-ray computed tomography. Then, it has been elevated as a general imaging principle. Finally, a novel framework known as “omni-tomography” is being developed for grand fusion of multiple imaging modalities, allowing tomographic synchrony of diversified features. PMID:23912256

Computational Analysis of Stresses Acting on Intermodular Junctions in Thoracic Aortic Endografts

PubMed Central

Prasad, Anamika; To, Lillian K.; Gorrepati, Madhu L.; Zarins, Christopher K.; Figueroa, C. Alberto

2011-01-01

Purpose: To evaluate the biomechanical and hemodynamic forces acting on the intermodular junctions of a multi-component thoracic endograft and elucidate their influence on the development of type III endoleak due to disconnection of stent-graft segments. Methods: Three-dimensional computer models of the thoracic aorta and a 4-component thoracic endograft were constructed using postoperative (baseline) and follow-up computed tomography (CT) data from a 69-year-old patient who developed type III endoleak 4 years after stent-graft placement. Computational fluid dynamics (CFD) techniques were used to quantitate the displacement forces acting on the device. The contact stresses between the different modules of the graft were then quantified using computational solid mechanics (CSM) techniques. Lastly, the intermodular junction frictional stability was evaluated using a Coulomb model. Results: The CFD analysis revealed that curvature and length are key determinants of the displacement forces experienced by each endograft and that the first 2 modules were exposed to displacement forces acting in opposite directions in both the lateral and longitudinal axes. The CSM analysis revealed that the highest concentration of stresses occurred at the junction between the first and second modules of the device. Furthermore, the frictional analysis demonstrated that most of the surface area (53%) of this junction had unstable contact. The predicted critical zone of intermodular stress concentration and frictional instability matched the location of the type III endoleak observed in the 4-year follow-up CT image. Conclusion: The region of larger intermodular stresses and highest frictional instability correlated with the zone where a type III endoleak developed 4 years after thoracic stent-graft placement. Computational techniques can be helpful in evaluating the risk of endograft migration and potential for modular disconnection and may be useful in improving device placement strategies and endograft design. PMID:21861748

Correlation between Preoperative High Resolution Computed Tomography (CT) Findings with Surgical Findings in Chronic Otitis Media (COM) Squamosal Type.

PubMed

Karki, S; Pokharel, M; Suwal, S; Poudel, R

Background The exact role of High resolution computed tomography (HRCT) temporal bone in preoperative assessment of Chronic suppurative otitis media atticoantral disease still remains controversial. Objective To evaluate the role of high resolution computed tomography temporal bone in Chronic suppurative otitis media atticoantral disease and to compare preoperative computed tomographic findings with intra-operative findings. Method Prospective, analytical study conducted among 65 patients with chronic suppurative otitis media atticoantral disease in Department of Radiodiagnosis, Kathmandu University Dhulikhel Hospital between January 2015 to July 2016. The operative findings were compared with results of imaging. The parameters of comparison were erosion of ossicles, scutum, facial canal, lateral semicircular canal, sigmoid and tegmen plate along with extension of disease to sinus tympani and facial recess. Sensitivity, specificity, negative predictive value, positive predictive values were calculated. Result High resolution computed tomography temporal bone offered sensitivity (Se) and specificity (Sp) of 100% for visualization of sigmoid and tegmen plate erosion. The performance of HRCT in detecting malleus (Se=100%, Sp=95.23%), incus (Se=100%,Sp=80.48%) and stapes (Se=96.55%, Sp=71.42%) erosion was excellent. It offered precise information about facial canal erosion (Se=100%, Sp=75%), scutum erosion (Se=100%, Sp=96.87%) and extension of disease to facial recess and sinus tympani (Se=83.33%,Sp=100%). high resolution computed tomography showed specificity of 100% for lateral semicircular canal erosion (Sp=100%) but with low sensitivity (Se=53.84%). Conclusion The findings of high resolution computed tomography and intra-operative findings were well comparable except for lateral semicircular canal erosion. high resolution computed tomography temporal bone acts as a road map for surgeon to identify the extent of disease, plan for appropriate procedure that is required and prepare for potential complications that can be encountered during surgery.

Trails on 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Leading to Diagnosis of Testicular Adrenal Rest Tumor.

PubMed

Kashyap, Raghava

2018-01-01

Testicular adrenal rest tumors (TARTs) are secondary to hypertrophy of adrenal rest cells in the rete testis in settings of hypersecretion of androgens. We present a case of congenital adrenal hyperplasia with TART with clues to the diagnosis on 18 F-fluorodeoxyglucose positron emission tomography/computed tomography ( 18 F-FDG PET/CT). To the best of our knowledge, this is the first reported case on the role of 18 F-FDG PET/CT in TART.

Pleuroperitoneal Mesothelioma: A Rare Entity on 18F-FDG PET/CT

PubMed Central

Sahoo, Manas Kumar; Mukherjee, Anirban; Girish; Parida, Kumar; Agarwal, Krishan Kant; Bal, Chandrasekhar; Tripathi, Madhavi; Das, Chandan Jyoti; Shamim, Shamim Ahmed

2017-01-01

Pleuroperitoneal mesothelioma is an extremely rare entity. Only few cases are reported worldwide. We hereby represent a case of pleural mesothelioma referred for F-18-Fluorodeoxyglucose positron emission tomography/computed tomography for response evaluation. Diffuse F-18-Fluorodeoxyglucose avid peritoneal and omental thickening noted which subsequently turned out to be mesothelial involvement on peritoneal biopsy. This case demonstrates the role of F-18-Fluorodeoxyglucose positron emission tomography/computed tomography in detecting other sites of involvement in case of malignant mesothelioma. PMID:28242997

Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography in Disseminated Cryptococcosis.

PubMed

Tripathy, Sarthak; Parida, Girish Kumar; Roy, Shambo Guha; Singhal, Abhinav; Mallick, Saumya Ranjan; Tripathi, Madhavi; Shamim, Shamim Ahmed

2017-01-01

Disseminated cryptococcosis without pulmonary involvement is a very rare phenomenon. Patterns of organ involvement in cryptococcosis resemble various other infective conditions as well as malignant conditions on fluorodeoxyglucose positron emission tomography-computed tomography. We present a case of a 43-year-old male patient who had disseminated cryptococcosis. The rarity of the case being noninvolvement of lungs and meninges and resembling more like lymphoma due to the diffuse involvement of the lymph nodes on both sides of the diaphragm.

Computed gray levels in multislice and cone-beam computed tomography.

PubMed

Azeredo, Fabiane; de Menezes, Luciane Macedo; Enciso, Reyes; Weissheimer, Andre; de Oliveira, Rogério Belle

2013-07-01

Gray level is the range of shades of gray in the pixels, representing the x-ray attenuation coefficient that allows for tissue density assessments in computed tomography (CT). An in-vitro study was performed to investigate the relationship between computed gray levels in 3 cone-beam CT (CBCT) scanners and 1 multislice spiral CT device using 5 software programs. Six materials (air, water, wax, acrylic, plaster, and gutta-percha) were scanned with the CBCT and CT scanners, and the computed gray levels for each material at predetermined points were measured with OsiriX Medical Imaging software (Geneva, Switzerland), OnDemand3D (CyberMed International, Seoul, Korea), E-Film (Merge Healthcare, Milwaukee, Wis), Dolphin Imaging (Dolphin Imaging & Management Solutions, Chatsworth, Calif), and InVivo Dental Software (Anatomage, San Jose, Calif). The repeatability of these measurements was calculated with intraclass correlation coefficients, and the gray levels were averaged to represent each material. Repeated analysis of variance tests were used to assess the differences in gray levels among scanners and materials. There were no differences in mean gray levels with the different software programs. There were significant differences in gray levels between scanners for each material evaluated (P <0.001). The software programs were reliable and had no influence on the CT and CBCT gray level measurements. However, the gray levels might have discrepancies when different CT and CBCT scanners are used. Therefore, caution is essential when interpreting or evaluating CBCT images because of the significant differences in gray levels between different CBCT scanners, and between CBCT and CT values. Copyright © 2013 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

CT Perfusion of the Head

MedlinePlus

... News Physician Resources Professions Site Index A-Z CT Perfusion of the Head Computed tomography (CT) perfusion ... of CT Perfusion of the Head? What is CT Perfusion of the Head? Computed tomography (CT) perfusion ...

Accuracy of image guidance using free-breathing cone-beam computed tomography for stereotactic lung radiotherapy.

PubMed

Kamomae, Takeshi; Monzen, Hajime; Nakayama, Shinichi; Mizote, Rika; Oonishi, Yuuichi; Kaneshige, Soichiro; Sakamoto, Takashi

2015-01-01

Movement of the target object during cone-beam computed tomography (CBCT) leads to motion blurring artifacts. The accuracy of manual image matching in image-guided radiotherapy depends on the image quality. We aimed to assess the accuracy of target position localization using free-breathing CBCT during stereotactic lung radiotherapy. The Vero4DRT linear accelerator device was used for the examinations. Reference point discrepancies between the MV X-ray beam and the CBCT system were calculated using a phantom device with a centrally mounted steel ball. The precision of manual image matching between the CBCT and the averaged intensity (AI) images restructured from four-dimensional CT (4DCT) was estimated with a respiratory motion phantom, as determined in evaluations by five independent operators. Reference point discrepancies between the MV X-ray beam and the CBCT image-guidance systems, categorized as left-right (LR), anterior-posterior (AP), and superior-inferior (SI), were 0.33 ± 0.09, 0.16 ± 0.07, and 0.05 ± 0.04 mm, respectively. The LR, AP, and SI values for residual errors from manual image matching were -0.03 ± 0.22, 0.07 ± 0.25, and -0.79 ± 0.68 mm, respectively. The accuracy of target position localization using the Vero4DRT system in our center was 1.07 ± 1.23 mm (2 SD). This study experimentally demonstrated the sufficient level of geometric accuracy using the free-breathing CBCT and the image-guidance system mounted on the Vero4DRT. However, the inter-observer variation and systematic localization error of image matching substantially affected the overall geometric accuracy. Therefore, when using the free-breathing CBCT images, careful consideration of image matching is especially important.

Detection of crestal radiolucencies around dental implants: an in vitro experimental study.

PubMed

Sirin, Yigit; Horasan, Sinan; Yaman, Duygu; Basegmez, Cansu; Tanyel, Cem; Aral, Ali; Guven, Koray

2012-07-01

The aim of this study was to compare the diagnostic potentials and practical advantages of different imaging modalities in detecting bone defects around dental implants. Crestal bone defects with sequentially larger diameters were randomly prepared around 100 implants that were inserted in bovine bone blocks. Conventional periapical radiography (PR), direct digital radiography (DDR), panoramic radiography (PANO), cone-beam computed tomography (CBCT), and multislice computed tomography (MSCT) were performed for all specimens. The diagnostic accuracies of the devices, confidence of the answers, subjective image quality, defect visibility in planar orientations, and duration of diagnosis were analyzed based on the interpretations of 7 calibrated observers. The agreement levels of intra- and interobserver scores were rated good. PR, DDR, and CBCT were mostly more accurate than PANO and MSCT (P < .05). Confidence levels were positively correlated with the defect size (ρ = 0.20, P < .01), and that of DDR was the highest (P < .05). The subjective image quality of PR and DDR was higher than that of CBCT, PANO, and MSCT (P < .05 for all comparisons). Axial-coronal-sagittal visibilities of the defects were higher for CBCT compared with MSCT (P < .05). The diagnostic time was shorter for DDR (P < .05) and longer for the tomographic systems (P < .05) than for the other devices. DDR may provide a faster and more confident diagnostic option that is as accurate as PR in detecting peri-implant radiolucencies. CBCT has a comparable potential to these intraoral systems but with slower decision making and lower image quality, whereas PANO and MSCT become more reliable when bone defects have a diameter that is at least 1.5 mm larger than that of the implant. Copyright © 2012 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Epicardial clip occlusion of the left atrial appendage during cardiac surgery provides optimal surgical results and long-term stability.

PubMed

Kurfirst, Vojtech; Mokrácek, Aleš; Canádyová, Júlia; Frána, Radim; Zeman, Petr

2017-07-01

Occlusion of the left atrial appendage (LAA) has become an integral and important part of the surgical treatment of atrial fibrillation. Different methods of surgical occlusion of the LAA have been associated with varying levels of short- and long-term success for closure. The purpose of this study was to evaluate long-term results of epicardial placement and endocardial occlusion in patients undergoing cardiac operative procedures. A total of 101 patients (average age 65.7 years) undergoing cardiac operative procedures with the epicardial AtriClip Exclusion System of the LAA were enrolled in the study. The AtriClip was placed via a sternotomy or a thoracotomy or from a thoracoscopic approach. Postoperative variables, such as thromboembolic events, clip stability and endocardial leakage around the device, were examined by transoesophageal echocardiography (TEE) and/or computed tomography. Perioperative clip implantation was achieved in 98% of patients. TEE and/or computed tomography conducted during the follow-up period, comprising 1873 patient-months with a mean duration of 18 ± 11 months, revealed no clip migration, no leakage around the device and no clot formation near the remnant cul-de-sac. During the follow-up period, 4 of the cardiac patients experienced transitory ischaemic attacks, whereas no patient experienced a cerebrovascular attack. The Epicardial AtriClip Exclusion System of the LAA appears to be a feasable and safe operative method with a high success rate. Long-term follow-up confirmed clip stability, complete occlussion of the LAA and absence of any atrial fibrilation-related thromboembolic events. These results need to be confirmed by a larger, multicentre study. © The Author 2017. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

Quantification of pericardial effusions by echocardiography and computed tomography.

PubMed

Leibowitz, David; Perlman, Gidon; Planer, David; Gilon, Dan; Berman, Philip; Bogot, Naama

2011-01-15

Echocardiography is a well-accepted tool for the diagnosis and quantification of pericardial effusion (PEff). Given the increasing use of computed tomographic (CT) scanning, more PEffs are being initially diagnosed by computed tomography. No study has compared quantification of PEff by computed tomography and echocardiography. The objective of this study was to assess the accuracy of quantification of PEff by 2-dimensional echocardiography and computed tomography compared to the amount of pericardial fluid drained at pericardiocentesis. We retrospectively reviewed an institutional database to identify patients who underwent chest computed tomography and echocardiography before percutaneous pericardiocentesis with documentation of the amount of fluid withdrawn. Digital 2-dimensional echocardiographic and CT images were retrieved and quantification of PEff volume was performed by applying the formula for the volume of a prolate ellipse, π × 4/3 × maximal long-axis dimension/2 × maximal transverse dimension/2 × maximal anteroposterior dimension/2, to the pericardial sac and to the heart. Nineteen patients meeting study qualifications were entered into the study. The amount of PEff drained was 200 to 1,700 ml (mean 674 ± 340). Echocardiographically calculated pericardial effusion volume correlated relatively well with PEff volume (r = 0.73, p <0.001, mean difference -41 ± 225 ml). There was only moderate correlation between CT volume quantification and actual volume drained (r = 0.4, p = 0.004, mean difference 158 ± 379 ml). In conclusion, echocardiography appears a more accurate imaging technique than computed tomography in quantitative assessment of nonloculated PEffs and should continue to be the primary imaging in these patients. Copyright © 2011 Elsevier Inc. All rights reserved.

Scalar localization of the electrode array after cochlear implantation: clinical experience using 64-slice multidetector computed tomography.

PubMed

Lane, John I; Witte, Robert J; Driscoll, Colin L W; Shallop, Jon K; Beatty, Charles W; Primak, Andrew N

2007-08-01

To use the improved resolution available with 64-slice multidetector computed tomography (MDCT) in vivo to localize the cochlear implant electrode array within the basal turn. Sixty-four-slice MDCT examinations of the temporal bones were retrospectively reviewed in 17 patients. Twenty-three implants were evaluated. Tertiary referral facility. All patients with previous cochlear implantation evaluated at our center between January 2004 and March 2006 were offered a computed tomographic examination as part of the study. In addition, preoperative computed tomographic examinations in patients being evaluated for a second bilateral device were included. Sixty-four-slice MDCT examination of the temporal bones. Localization of the electrode array within the basal turn from multiplanar reconstructions of the cochlea. Twenty-three implants were imaged in 17 patients. We were able to localize the electrode array within the scala tympani within the basal turn in 10 implants. In 3 implants, the electrode array was localized to the scala vestibuli. Migration of the electrode array from scala tympani to scala vestibuli was observed in three implants. Of the 7 implants in which localization of the electrode array was indeterminate, all had disease entities that obscured the definition of the normal cochlear anatomy. Sixty-four-slice MDCT with multiplanar reconstructions of the postoperative cochlea after cochlear implantation allows for accurate localization of the electrode array within the basal turn where normal cochlear anatomy is not obscured by the underlying disease process. Correlating the position of the electrode in the basal turn with surgical technique and implant design could be helpful in improving outcomes.

Development of computational small animal models and their applications in preclinical imaging and therapy research

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

Xie, Tianwu; Zaidi, Habib, E-mail: habib.zaidi@hcuge.ch; Geneva Neuroscience Center, Geneva University, Geneva CH-1205

The development of multimodality preclinical imaging techniques and the rapid growth of realistic computer simulation tools have promoted the construction and application of computational laboratory animal models in preclinical research. Since the early 1990s, over 120 realistic computational animal models have been reported in the literature and used as surrogates to characterize the anatomy of actual animals for the simulation of preclinical studies involving the use of bioluminescence tomography, fluorescence molecular tomography, positron emission tomography, single-photon emission computed tomography, microcomputed tomography, magnetic resonance imaging, and optical imaging. Other applications include electromagnetic field simulation, ionizing and nonionizing radiation dosimetry, and themore » development and evaluation of new methodologies for multimodality image coregistration, segmentation, and reconstruction of small animal images. This paper provides a comprehensive review of the history and fundamental technologies used for the development of computational small animal models with a particular focus on their application in preclinical imaging as well as nonionizing and ionizing radiation dosimetry calculations. An overview of the overall process involved in the design of these models, including the fundamental elements used for the construction of different types of computational models, the identification of original anatomical data, the simulation tools used for solving various computational problems, and the applications of computational animal models in preclinical research. The authors also analyze the characteristics of categories of computational models (stylized, voxel-based, and boundary representation) and discuss the technical challenges faced at the present time as well as research needs in the future.« less

[Computed tomography semiotics of osteonecrosis and sequestration in chronic hematogenic osteomyelitis].

PubMed

D'iachkova, G V; Mitina, Iu L

2007-01-01

Based on the data of computed tomography, radiography and densitometry in 39 patients the authors describe in detail the signs of osteonecrosis and sequestration of different localization and extension.

Pelvic CT scan

MedlinePlus

CAT scan - pelvis; Computed axial tomography scan - pelvis; Computed tomography scan - pelvis; CT scan - pelvis ... Risks of CT scans include: Being exposed to radiation Allergic reaction to contrast dye CT scans do expose you to more radiation ...

Lumbar spine CT scan

MedlinePlus

CAT scan - lumbar spine; Computed axial tomography scan - lumbar spine; Computed tomography scan - lumbar spine; CT - lower back ... CT scans rapidly makes detailed pictures of the lower back. The test may be used to look for: ...

Shoulder CT scan

MedlinePlus

CAT scan - shoulder; Computed axial tomography scan - shoulder; Computed tomography scan - shoulder; CT scan - shoulder ... Risks of CT scans include: Being exposed to radiation Allergic reaction to contrast dye Birth defect if done during pregnancy CT scans ...

SPECT/CT in imaging foot and ankle pathology-the demise of other coregistration techniques.

PubMed

Mohan, Hosahalli K; Gnanasegaran, Gopinath; Vijayanathan, Sanjay; Fogelman, Ignac

2010-01-01

Disorders of the ankle and foot are common and given the complex anatomy and function of the foot, they present a significant clinical challenge. Imaging plays a crucial role in the management of these patients, with multiple imaging options available to the clinician. The American College of radiology has set the appropriateness criteria for the use of the available investigating modalities in the management of foot and ankle pathologies. These are broadly classified into anatomical and functional imaging modalities. Recently, single-photon emission computed tomography and/or computed tomography scanners, which can elegantly combine functional and anatomical images have been introduced, promising an exciting and important development. This review describes our clinical experience with single-photon emission computed tomography and/or computed tomography and discusses potential applications of these techniques.

Comparison of radiological and morphologic assessments of myocardial bridges.

PubMed

Ercakmak, Burcu; Bulut, Elif; Hayran, Mutlu; Kaymaz, Figen; Bilgin, Selma; Hazirolan, Tuncay; Bayramoglu, Alp; Erbil, Mine

2015-09-01

In this study we aimed to compare the findings of coronary dual-source computed tomography angiography of myocardial bridges with cadaveric dissections. Forty-one isolated, non-damaged fresh sheep hearts were used in this study. Myocardial bridges of the anterior interventricular branch of the left coronary artery were demonstrated and analyzed by a coronary dual-source computed tomography angiography. Dissections along the left anterior interventricular branch of the left coronary artery were performed by using Zeiss OPMI pico microscope and the length of the bridges were measured. The depths of the myocardial bridges were measured from the stained sections by using the light microscope (Leica DM 6000B). MBs were found in all 41 hearts (100%) during dissections. Dual-source computed tomography angiography successfully detected 87.8% (36 of the 41 hearts) of the myocardial bridges measured on left anterior interventricular branch of left coronary artery. The lengths of the myocardial bridges were found 5-40 and 8-50 mm with dissection and dual-source computed tomography angiography, respectively. And the depths were found 0.7-4.5 mm by dual-source computed tomography angiography and 0.745-4.632 mm morphologically. Comparison of the mean values of the lengths showed statistically significantly higher values (22.0 ± 8.5, 17.7 ± 7.7 mm, p = 0.003) for the dissections. Radiological assessment also effectively discriminated complete bridges from incomplete ones. Our study showed that coronary computed tomography angiography is reliable in evaluating the presence and depth of myocardial bridges.

3D ultrasound computer tomography: Hardware setup, reconstruction methods and first clinical results

NASA Astrophysics Data System (ADS)

Gemmeke, Hartmut; Hopp, Torsten; Zapf, Michael; Kaiser, Clemens; Ruiter, Nicole V.

2017-11-01

A promising candidate for improved imaging of breast cancer is ultrasound computer tomography (USCT). Current experimental USCT systems are still focused in elevation dimension resulting in a large slice thickness, limited depth of field, loss of out-of-plane reflections, and a large number of movement steps to acquire a stack of images. 3D USCT emitting and receiving spherical wave fronts overcomes these limitations. We built an optimized 3D USCT, realizing for the first time the full benefits of a 3D system. The point spread function could be shown to be nearly isotropic in 3D, to have very low spatial variability and fit the predicted values. The contrast of the phantom images is very satisfactory in spite of imaging with a sparse aperture. The resolution and imaged details of the reflectivity reconstruction are comparable to a 3 T MRI volume. Important for the obtained resolution are the simultaneously obtained results of the transmission tomography. The KIT 3D USCT was then tested in a pilot study on ten patients. The primary goals of the pilot study were to test the USCT device, the data acquisition protocols, the image reconstruction methods and the image fusion techniques in a clinical environment. The study was conducted successfully; the data acquisition could be carried out for all patients with an average imaging time of six minutes per breast. The reconstructions provide promising images. Overlaid volumes of the modalities show qualitative and quantitative information at a glance. This paper gives a summary of the involved techniques, methods, and first results.

Spectral optical coherence tomography for ophthalmologic applications

NASA Astrophysics Data System (ADS)

Targowski, Piotr; Bajraszewski, Tomasz; Gorczyńska, Iwona; Szkulmowska, Anna; Szkulmowski, Maciej; Wojtkowski, Maciej; Kowalczyk, Andrzej; Kaluzny, Jakub J.; Kaluzny, Bartłomiej J.

2006-09-01

The overview of the Spectral Optical Coherence Tomography an alternative method to more popular Time domain modality is given. Examples from medical practice utilizing high resolution, ultra fast SOCT device are presented.

Sinus CT scan

MedlinePlus

CAT scan - sinus; Computed axial tomography scan - sinus; Computed tomography scan - sinus; CT scan - sinus ... Risks for a CT scan includes: Being exposed to radiation Allergic reaction to contrast dye CT scans expose you to more radiation than regular ...

Brain PET scan

MedlinePlus

... tissues are working. Other imaging tests, such as magnetic resonance imaging ( MRI ) and computed tomography ( CT ) scans only reveal ... M, Hellwig S, Kloppel S, Weiller C. Functional neuroimaging: functional magnetic resonance imaging, positron emission tomography, and single-photon emission computed ...

Fiber Optic Communication System For Medical Images

NASA Astrophysics Data System (ADS)

Arenson, Ronald L.; Morton, Dan E.; London, Jack W.

1982-01-01

This paper discusses a fiber optic communication system linking ultrasound devices, Computerized tomography scanners, Nuclear Medicine computer system, and a digital fluoro-graphic system to a central radiology research computer. These centrally archived images are available for near instantaneous recall at various display consoles. When a suitable laser optical disk is available for mass storage, more extensive image archiving will be added to the network including digitized images of standard radiographs for comparison purposes and for remote display in such areas as the intensive care units, the operating room, and selected outpatient departments. This fiber optic system allows for a transfer of high resolution images in less than a second over distances exceeding 2,000 feet. The advantages of using fiber optic cables instead of typical parallel or serial communication techniques will be described. The switching methodology and communication protocols will also be discussed.

Imaging of the interaction of low frequency electric fields with biological tissues by optical coherence tomography

NASA Astrophysics Data System (ADS)

Peña, Adrian F.; Devine, Jack; Doronin, Alexander; Meglinski, Igor

2014-03-01

We report the use of conventional Optical Coherence Tomography (OCT) for visualization of propagation of low frequency electric field in soft biological tissues ex vivo. To increase the overall quality of the experimental images an adaptive Wiener filtering technique has been employed. Fourier domain correlation has been subsequently applied to enhance spatial resolution of images of biological tissues influenced by low frequency electric field. Image processing has been performed on Graphics Processing Units (GPUs) utilizing Compute Unified Device Architecture (CUDA) framework in the frequencydomain. The results show that variation in voltage and frequency of the applied electric field relates exponentially to the magnitude of its influence on biological tissue. The magnitude of influence is about twice more for fresh tissue samples in comparison to non-fresh ones. The obtained results suggest that OCT can be used for observation and quantitative evaluation of the electro-kinetic changes in biological tissues under different physiological conditions, functional electrical stimulation, and potentially can be used non-invasively for food quality control.

Impact of 3-dimensional-computed tomography workstation for precise planning of endovascular aneurysm repair.

PubMed

Higashiura, Wataru; Sakaguchi, Shoji; Tabayashi, Nobuoki; Taniguchi, Shigeki; Kichikawa, Kimihiko

2008-12-01

Compared with open surgery, imaging is considered to be important for planning and device selection of endovascular aneurysm repair (EVAR). The present study evaluated the usefulness of a 3-dimensional (3D)-computed tomography (CT) workstation in planning EVAR. A prospective study was conducted in 8 patients who underwent EVAR using Zenith endograft between February and August 2007. Endograft size and optimized deployment projection were decided using a 3D-CT workstation. The primary endpoint was defined as successful deployment of a same size endograft as preoperatively selected without type I or III endoleak or inadvertent arterial occlusion. The following parameters were investigated: (a) incidence of use of an alternative endograft; (b) prevalence of type I or III endoleak; and (c) distance from lowest renal artery to tip of graft. Successful deployment of endograft was achieved in all 8 patients. Use of alternative endograft or type I or III endoleak was not detected in 8 patients. Distance from the lowest renal artery to the tip of the graft was 2.8mm. Assessment using a 3D-CT workstation appears to allow accurate endograft selection and precise deployment of the Zenith endograft without type I or III endoleak, even in institutes with a small number of patients.

Brilliant gamma beams for industrial applications: new opportunities, new challenges

NASA Astrophysics Data System (ADS)

Iancu, V.; Suliman, G.; Turturica, G. V.; Iovea, M.; Daito, I.; Ohgaki, H.; Matei, C.; Ur, C. A.; Balabanski, D. L.

2016-10-01

The Nuclear Physics oriented pillar of the pan-European Extreme Light Infrastructure (ELI-NP) will host an ultra-bright, energy tunable, and quasi-monochromatic gamma-ray beam system in the range of 0.2-19.5 MeV produced by laser-Compton backscattering technique. The applied research program envisioned at ELI-NP targets to use nuclear resonance fluorescence (NRF) and computed tomography to provide new opportunities for industry and society. High sensitivity NRF-based investigations can be successfully applied to safeguard applications and management of radioactive wastes as well as to uncharted fields like cultural heritage and medical imaging. Gamma-ray radioscopy and computed tomography performed at ELI-NP has the potential to achieve high resolution in industrial-sized objects provided the detection challenges introduced by the unique characteristics of the gamma beam are overcome. Here we discuss the foreseen industrial applications that will benefit from the high quality and unique characteristics of ELI-NP gamma beam and the challenges they present. We present the experimental setups proposed to be implemented for this goal, discuss their performance based on analytical calculations and numerical Monte-Carlo simulations, and comment about constrains imposed by the limitation of current scintillator detectors. Several gamma-beam monitoring devices based on scintillator detectors will also be discussed.

Characterization of OSL dosimeters for use in dose assessment in Computed Tomography procedures.

PubMed

Giansante, Louise; Santos, Josilene C; Umisedo, Nancy K; Terini, Ricardo A; Costa, Paulo R

2018-03-01

This study describes the characterization of an Al 2 O 3 :C OSLD (Landauer's Luxel™ tape) for dose evaluation in Computed Tomography. The irradiations were conducted using both a constant potential X-ray equipment and a 64-slice clinical CT scanner, and the readouts were performed using a Risø TL/OSL reader. The following aspects were studied: batch homogeneity, energy response, linearity of dose response, reproducibility, reusability, and effect of uncertainties with the normalization of OSL signals per their response to beta radiation. A group of 330 dosimeters from the 452 irradiated with the same dose presented OSL signals within the interval of 4.7% from the average. The dosimeters presented energy-dependent response in good agreement with results found in the literature. The air kerma response of the OSL signal showed a linear trend for both the constant potential X-ray device and the clinical CT scanner, with differences in their slopes of approximately 10%. Reproducibility, reusability, and effect of beta normalization were analyzed by separating 72 dosimeters in 3 groups. The results obtained in this study together with those of previous works indicate that this type of dosimeter is adequate for dose evaluation in CT clinical applications. Copyright © 2018 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Concept of a selective tumour therapy and its evaluation by near-infrared fluorescence imaging and flat-panel volume computed tomography in mice.

PubMed

Alves, Frauke; Dullin, Christian; Napp, Joanna; Missbach-Guentner, Jeannine; Jannasch, Katharina; Mathejczyk, Julia; Pardo, Luis A; Stühmer, Walter; Tietze, Lutz-F

2009-05-01

Conventional chemotherapy of cancer has its limitations, especially in advanced and disseminated disease and suffers from lack of specificity. This results in a poor therapeutic index and considerable toxicity to normal organs. Therefore, many efforts are made to develop novel therapeutic tools against cancer with the aim of selectively targeting the drug to the tumour site. Drug delivery strategies fundamentally rely on the identification of good-quality biomarkers, allowing unequivocal discrimination between cancer and healthy tissue. At present, antibodies or antibody fragments have clearly proven their value as carrier molecules specific for a tumour-associated molecular marker. This present review draws attention to the use of near-infrared fluorescence (NIRF) imaging to investigate binding specificity and kinetics of carrier molecules such as monoclonal antibodies. In addition, flat-panel volume computed tomography (fpVCT) will be presented to monitor anatomical structures in tumour mouse models over time in a non-invasive manner. Each imaging device sheds light on a different aspect; functional imaging is applied to optimise the dose schedule and the concept of selective tumour therapies, whereas anatomical imaging assesses preclinically the efficacy of novel tumour therapies. Both imaging techniques in combination allow the visualisation of functional information obtained by NIRF imaging within an adequate anatomic framework.

Pediatric Phantom Dosimetry of Kodak 9000 Cone-beam Computed Tomography.

PubMed

Yepes, Juan F; Booe, Megan R; Sanders, Brian J; Jones, James E; Ehrlich, Ygal; Ludlow, John B; Johnson, Brandon

2017-05-15

The purpose of the study was to evaluate the radiation dose of the Kodak 9000 cone-beam computed tomography (CBCT) device for different anatomical areas using a pediatric phantom. Absorbed doses resulting from maxillary and mandibular region three by five cm CBCT volumes of an anthropomorphic 10-year-old child phantom were acquired using optical stimulated dosimetry. Equivalent doses were calculated for radiosensitive tissues in the head and neck area, and effective dose for maxillary and mandibular examinations were calculated following the 2007 recommendations of the International Commission on Radiological Protection (ICRP). Of the mandibular scans, the salivary glands had the highest equivalent dose (1,598 microsieverts [μSv]), followed by oral mucosa (1,263 μSv), extrathoracic airway (pharynx, larynx, and trachea; 859 μSv), and thyroid gland (578 μSv). For the maxilla, the salivary glands had the highest equivalent dose (1,847 μSv), followed closely by oral mucosa (1,673 μSv), followed by the extrathoracic airway (pharynx, larynx, and trachea; 1,011 μSv) and lens of the eye (202 μSv). Compared to previous research of the Kodak 9000, completed with the adult phantom, a child receives one to three times more radiation for mandibular scans and two to 10 times more radiation for maxillary scans.

Delayed enhancement cardiac computed tomography for the assessment of myocardial infarction: from bench to bedside

PubMed Central

2017-01-01

A large number of studies support the increasingly relevant prognostic value of the presence and extent of delayed enhancement (DE), a surrogate marker of fibrosis, in diverse etiologies. Gadolinium and iodinated based contrast agents share similar kinetics, thus leading to comparable myocardial characterization with cardiac magnetic resonance (CMR) and cardiac computed tomography (CT) at both first-pass perfusion and DE imaging. We review the available evidence of DE imaging for the assessment of myocardial infarction (MI) using cardiac CT (CTDE), from animal to clinical studies, and from 16-slice CT to dual-energy CT systems (DECT). Although both CMR and gadolinium agents have been originally deemed innocuous, a number of concerns (though inconclusive and very rare) have been recently issued regarding safety issues, including DNA double-strand breaks related to CMR, and gadolinium-associated nephrogenic systemic fibrosis and deposition in the skin and certain brain structures. These concerns have to be considered in the context of non-negligible rates of claustrophobia, increasing rates of patients with implantable cardiac devices, and a number of logistic drawbacks compared with CTDE, such as higher costs, longer scanning times, and difficulties to scan patients with impaired breath-holding capabilities. Overall, these issues might encourage the role of CTDE as an alternative for DE-CMR in selected populations. PMID:28540211

Microstructure of cotton fibrous assemblies based on computed tomography

NASA Astrophysics Data System (ADS)

Jing, Hui; Yu, Weidong

2017-12-01

This paper describes for the first time the analysis of inner microstructure of cotton fibrous assemblies using computed tomography. Microstructure parameters such as packing density, fractal dimension as well as porosity including open porosity, closed porosity and total porosity are calculated based on 2D data from computed tomography. Values of packing density and fractal dimension are stable in random oriented fibrous assemblies, and there exists a satisfactory approximate linear relationship between them. Moreover, poles analysis indicates that porosity represents the tightness of fibrous assemblies and open poles are main existence.

Progress of projection computed tomography by upgrading of the beamline 37XU of SPring-8

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

Terada, Yasuko, E-mail: yterada@spring8.or.jp; Suzuki, Yoshio; Uesugi, Kentaro

2016-01-28

Beamline 37XU at SPring-8 has been upgraded for nano-focusing applications. The length of the beamline has been extended to 80 m. By utilizing this length, the beamline has advantages for experiments such as X-ray focusing, X-ray microscopic imaging and X-ray computed tomography. Projection computed tomography measurements were carried out at experimental hutch 3 located 80 m from the light source. CT images of a microcapsule have been successfully obtained with a wide X-ray energy range.

The use of iohexol as oral contrast for computed tomography of the abdomen and pelvis.

PubMed

Horton, Karen M; Fishman, Elliot K; Gayler, Bob

2008-01-01

Positive oral contrast agents (high-osmolar iodinated solutions [high-osmolar contrast medium] or barium sulfate suspensions) are used routinely for abdominal computed tomography. However, these agents are not ideal. Patients complain about the taste and, sometimes, refuse to drink the required quantity. Nausea, vomiting, and diarrhea are frequent. In certain clinical indications, either barium suspensions or high-osmolar contrast mediums may be contraindicated. This technical note describes the potential advantages of using low-osmolar iodinated solutions as an oral contrast agent for computed tomography.

Phase-contrast x-ray computed tomography for observing biological specimens and organic materials

NASA Astrophysics Data System (ADS)

Momose, Atsushi; Takeda, Tohoru; Itai, Yuji

1995-02-01

A novel three-dimensional x-ray imaging method has been developed by combining a phase-contrast x-ray imaging technique with x-ray computed tomography. This phase-contrast x-ray computed tomography (PCX-CT) provides sectional images of organic specimens that would produce absorption-contrast x-ray CT images with little contrast. Comparing PCX-CT images of rat cerebellum and cancerous rabbit liver specimens with corresponding absorption-contrast CT images shows that PCX-CT is much more sensitive to the internal structure of organic specimens.

Applying LED in full-field optical coherence tomography for gastrointestinal endoscopy

NASA Astrophysics Data System (ADS)

Yang, Bor-Wen; Wang, Yu-Yen; Juan, Yu-Shan; Hsu, Sheng-Jie

2015-08-01

Optical coherence tomography (OCT) has become an important medical imaging technology due to its non-invasiveness and high resolution. Full-field optical coherence tomography (FF-OCT) is a scanning scheme especially suitable for en face imaging as it employs a CMOS/CCD device for parallel pixels processing. FF-OCT can also be applied to high-speed endoscopic imaging. Applying cylindrical scanning and a right-angle prism, we successfully obtained a 360° tomography of the inner wall of an intestinal cavity through an FF-OCT system with an LED source. The 10-μm scale resolution enables the early detection of gastrointestinal lesions, which can increase detection rates for esophageal, stomach, or vaginal cancer. All devices used in this system can be integrated by MOEMS technology to contribute to the studies of gastrointestinal medicine and advanced endoscopy technology.

Contours identification of elements in a cone beam computed tomography for investigating maxillary cysts

NASA Astrophysics Data System (ADS)

Chioran, Doina; Nicoarǎ, Adrian; Roşu, Şerban; Cǎrligeriu, Virgil; Ianeş, Emilia

2013-10-01

Digital processing of two-dimensional cone beam computer tomography slicesstarts by identification of the contour of elements within. This paper deals with the collective work of specialists in medicine and applied mathematics in computer science on elaborating and implementation of algorithms in dental 2D imagery.

Neuroanatomy of cranial computed tomography

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

Kretschmann, H.J.; Weinrich, W.

1985-01-01

Based on the fundamental structures visualized by means of computed tomography, the authors present the functional systems which are relevant in neurology by means of axial cross-sections. All drawings were prepared from original preparations by means of a new technique which is similar to the grey values of X-ray CT and nuclear magnetic resonance tomography. A detailed description is given of the topics of neurofunctional lesions.

Frozen Gaussian approximation for 3D seismic tomography

NASA Astrophysics Data System (ADS)

Chai, Lihui; Tong, Ping; Yang, Xu

2018-05-01

Three-dimensional (3D) wave-equation-based seismic tomography is computationally challenging in large scales and high-frequency regime. In this paper, we apply the frozen Gaussian approximation (FGA) method to compute 3D sensitivity kernels and seismic tomography of high-frequency. Rather than standard ray theory used in seismic inversion (e.g. Kirchhoff migration and Gaussian beam migration), FGA is used to compute the 3D high-frequency sensitivity kernels for travel-time or full waveform inversions. Specifically, we reformulate the equations of the forward and adjoint wavefields for the purpose of convenience to apply FGA, and with this reformulation, one can efficiently compute the Green’s functions whose convolutions with source time function produce wavefields needed for the construction of 3D kernels. Moreover, a fast summation method is proposed based on local fast Fourier transform which greatly improves the speed of reconstruction as the last step of FGA algorithm. We apply FGA to both the travel-time adjoint tomography and full waveform inversion (FWI) on synthetic crosswell seismic data with dominant frequencies as high as those of real crosswell data, and confirm again that FWI requires a more sophisticated initial velocity model for the convergence than travel-time adjoint tomography. We also numerically test the accuracy of applying FGA to local earthquake tomography. This study paves the way to directly apply wave-equation-based seismic tomography methods into real data around their dominant frequencies.

Pediatric minor head trauma: do cranial CT scans change the therapeutic approach?

PubMed

Andrade, Felipe P; Montoro, Roberto; Oliveira, Renan; Loures, Gabriela; Flessak, Luana; Gross, Roberta; Donnabella, Camille; Puchnick, Andrea; Suzuki, Lisa; Regacini, Rodrigo

2016-10-01

1) To verify clinical signs correlated with appropriate cranial computed tomography scan indications and changes in the therapeutic approach in pediatric minor head trauma scenarios. 2) To estimate the radiation exposure of computed tomography scans with low dose protocols in the context of trauma and the additional associated risk. Investigators reviewed the medical records of all children with minor head trauma, which was defined as a Glasgow coma scale ≥13 at the time of admission to the emergency room, who underwent computed tomography scans during the years of 2013 and 2014. A change in the therapeutic approach was defined as a neurosurgical intervention performed within 30 days, hospitalization, >12 hours of observation, or neuro-specialist evaluation. Of the 1006 children evaluated, 101 showed some abnormality on head computed tomography scans, including 49 who were hospitalized, 16 who remained under observation and 36 who were dismissed. No patient underwent neurosurgery. No statistically significant relationship was observed between patient age, time between trauma and admission, or signs/symptoms related to trauma and abnormal imaging results. A statistically significant relationship between abnormal image results and a fall higher than 1.0 meter was observed (p=0.044). The mean effective dose was 2.0 mSv (0.1 to 6.8 mSv), corresponding to an estimated additional cancer risk of 0.05%. A computed tomography scan after minor head injury in pediatric patients did not show clinically relevant abnormalities that could lead to neurosurgical indications. Patients who fell more than 1.0 m were more likely to have changes in imaging tests, although these changes did not require neurosurgical intervention; therefore, the use of computed tomography scans may be questioned in this group. The results support the trend of more careful indications for cranial computed tomography scans for children with minor head trauma.

Computed Tomography Perfusion, Magnetic Resonance Imaging, and Histopathological Findings After Laparoscopic Renal Cryoablation: An In Vivo Pig Model.

PubMed

Nielsen, Tommy Kjærgaard; Østraat, Øyvind; Graumann, Ole; Pedersen, Bodil Ginnerup; Andersen, Gratien; Høyer, Søren; Borre, Michael

2017-08-01

The present study investigates how computed tomography perfusion scans and magnetic resonance imaging correlates with the histopathological alterations in renal tissue after cryoablation. A total of 15 pigs were subjected to laparoscopic-assisted cryoablation on both kidneys. After intervention, each animal was randomized to a postoperative follow-up period of 1, 2, or 4 weeks, after which computed tomography perfusion and magnetic resonance imaging scans were performed. Immediately after imaging, open bilateral nephrectomy was performed allowing for histopathological examination of the cryolesions. On computed tomography perfusion and magnetic resonance imaging examinations, rim enhancement was observed in the transition zone of the cryolesion 1week after laparoscopic-assisted cryoablation. This rim enhancement was found to subside after 2 and 4 weeks of follow-up, which was consistent with the microscopic examinations revealing of fibrotic scar tissue formation in the peripheral zone of the cryolesion. On T2 magnetic resonance imaging sequences, a thin hypointense rim surrounded the cryolesion, separating it from the adjacent renal parenchyma. Microscopic examinations revealed hemorrhage and later hemosiderin located in the peripheral zone. No nodular or diffuse contrast enhancement was found in the central zone of the cryolesions at any follow-up stage on neither computed tomography perfusion nor magnetic resonance imaging. On microscopic examinations, the central zone was found to consist of coagulative necrosis 1 week after laparoscopic-assisted cryoablation, which was partially replaced by fibrotic scar tissue 4 weeks following laparoscopic-assisted cryoablation. Both computed tomography perfusion and magnetic resonance imaging found the renal collecting system to be involved at all 3 stages of follow-up, but on microscopic examination, the urothelium was found to be intact in all cases. In conclusion, cryoablation effectively destroyed renal parenchyma, leaving the urothelium intact. Both computed tomography perfusion and magnetic resonance imaging reflect the microscopic findings but with some differences, especially regarding the peripheral zone. Magnetic resonance imaging seems an attractive modality for early postoperative follow-up.

Pictorial review of radiographic patterns of injury in modern warfare: imaging the conflict in Afghanistan.

PubMed

Peramaki, Ed R

2011-05-01

Radiographic assessment of combat injuries has been an important component of casualty care in every major conflict of the 20th and 21st centuries. The advent of multislice computed tomography scanners has provided physicians with the ability to visualize organ injury at submillimetre resolution, changing the way war wounds are treated. Modern wars are, for the most part, asymmetric conflicts where improvised explosive devices have replaced artillery as a major cause of casualties. Both bullets and explosive devices wreak distinctive patterns of injury on the human body. Being able to recognize these patterns and their potential associated morbidities will allow medical personnel to provide expert and timely care to some of the most severely injured patients on earth. This series of pictorial essays will review the radiographic patterns of combat-related injury encountered in southern Afghanistan in 2008-2009.

Computed tomography or rhinoscopy as the first-line procedure for suspected nasal tumor: a pilot study.

PubMed

Finck, Marlène; Ponce, Frédérique; Guilbaud, Laurent; Chervier, Cindy; Floch, Franck; Cadoré, Jean-Luc; Chuzel, Thomas; Hugonnard, Marine

2015-02-01

There are no evidence-based guidelines as to whether computed tomography (CT) or endoscopy should be selected as the first-line procedure when a nasal tumor is suspected in a dog or a cat and only one examination can be performed. Computed tomography and rhinoscopic features of 17 dogs and 5 cats with a histopathologically or cytologically confirmed nasal tumor were retrospectively reviewed. The level of suspicion for nasal neoplasia after CT and/or rhinoscopy was compared to the definitive diagnosis. Twelve animals underwent CT, 14 underwent rhinoscopy, and 4 both examinations. Of the 12 CT examinations performed, 11 (92%) resulted in the conclusion that a nasal tumor was the most likely diagnosis compared with 9/14 (64%) for rhinoscopies. Computed tomography appeared to be more reliable than rhinoscopy for detecting nasal tumors and should therefore be considered as the first-line procedure.

Computed tomography or rhinoscopy as the first-line procedure for suspected nasal tumor: A pilot study

PubMed Central

Finck, Marlène; Ponce, Frédérique; Guilbaud, Laurent; Chervier, Cindy; Floch, Franck; Cadoré, Jean-Luc; Chuzel, Thomas; Hugonnard, Marine

2015-01-01

There are no evidence-based guidelines as to whether computed tomography (CT) or endoscopy should be selected as the first-line procedure when a nasal tumor is suspected in a dog or a cat and only one examination can be performed. Computed tomography and rhinoscopic features of 17 dogs and 5 cats with a histopathologically or cytologically confirmed nasal tumor were retrospectively reviewed. The level of suspicion for nasal neoplasia after CT and/or rhinoscopy was compared to the definitive diagnosis. Twelve animals underwent CT, 14 underwent rhinoscopy, and 4 both examinations. Of the 12 CT examinations performed, 11 (92%) resulted in the conclusion that a nasal tumor was the most likely diagnosis compared with 9/14 (64%) for rhinoscopies. Computed tomography appeared to be more reliable than rhinoscopy for detecting nasal tumors and should therefore be considered as the first-line procedure. PMID:25694669

Review of cardiovascular imaging in The Journal of Nuclear Cardiology in 2014: Part 1 of 2: Positron emission tomography, computed tomography, and neuronal imaging.

PubMed

AlJaroudi, Wael A; Hage, Fadi G

2015-06-01

The year 2014 has been an exciting year for the cardiovascular imaging community with significant advances in the realm of nuclear and multimodality cardiac imaging. In this new feature of the Journal of Nuclear Cardiology, we will summarize some of the breakthroughs that were published in the Journal in 2014 in 2 sister articles. This first article will concentrate on publications dealing with cardiac positron emission tomography (PET), computed tomography (CT), and neuronal imaging.

Trends in micro- and nanoComputed Tomography 2008-2010

NASA Astrophysics Data System (ADS)

Stock, S. R.

2010-09-01

Trends in micro- and nanoComputed Tomography (CT) from January 2008 through July 2010 are the subject of this brief report which takes up where a previous report in Developments in X-ray Tomography VI (2008) concluded. First, the number of systems operating world-wide is estimated. The main focus is on what searches of three citation indices (Web of Science, Compendex and PubMed) reveal about the field of micro- and nanoCT. Given research-fielddependent and disparate terminology used by investigators, searches were on "microtomography", "microCT" and "synchrotron tomography".

Electron beam diagnostic system using computed tomography and an annular sensor

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

Elmer, John W.; Teruya, Alan T.

2015-08-11

A system for analyzing an electron beam including a circular electron beam diagnostic sensor adapted to receive the electron beam, the circular electron beam diagnostic sensor having a central axis; an annular sensor structure operatively connected to the circular electron beam diagnostic sensor, wherein the sensor structure receives the electron beam; a system for sweeping the electron beam radially outward from the central axis of the circular electron beam diagnostic sensor to the annular sensor structure wherein the electron beam is intercepted by the annular sensor structure; and a device for measuring the electron beam that is intercepted by themore » annular sensor structure.« less

Ischemic Stroke: Advances in Diagnosis and Management.

PubMed

Cassella, Courtney R; Jagoda, Andy

2017-11-01

Acute ischemic stroke carries the risk of morbidity and mortality. Since the advent of intravenous thrombolysis, there have been improvements in stroke care and functional outcomes. Studies of populations once excluded from thrombolysis have begun to elucidate candidates who might benefit and thus should be engaged in the process of shared decision-making. Imaging is evolving to better target the ischemic penumbra salvageable with prompt reperfusion. Availability and use of computed tomography angiography identifies large-vessel occlusions, and new-generation endovascular therapy devices are improving outcomes in these patients. With this progress in stroke treatment, risk stratification tools and shared decision-making are fundamental. Copyright © 2017 Elsevier Inc. All rights reserved.

Electron beam diagnostic system using computed tomography and an annular sensor

DOEpatents

Elmer, John W.; Teruya, Alan T.

2014-07-29

A system for analyzing an electron beam including a circular electron beam diagnostic sensor adapted to receive the electron beam, the circular electron beam diagnostic sensor having a central axis; an annular sensor structure operatively connected to the circular electron beam diagnostic sensor, wherein the sensor structure receives the electron beam; a system for sweeping the electron beam radially outward from the central axis of the circular electron beam diagnostic sensor to the annular sensor structure wherein the electron beam is intercepted by the annular sensor structure; and a device for measuring the electron beam that is intercepted by the annular sensor structure.

Custom Titanium Ridge Augmentation Matrix (CTRAM): A Case Report.

PubMed

Connors, Christopher A; Liacouras, Peter C; Grant, Gerald T

2016-01-01

This is a case report of a custom titanium ridge augmentation matrix (CTRAM). Using cone beam computed tomography (CBCT), a custom titanium space-maintaining device was developed. Alveolar ridges were virtually augmented, a matrix was virtually designed, and the CTRAM was additively manufactured with titanium (Ti6Al4V). Two cases are presented that resulted in sufficient increased horizontal bone volume with successful dental implant placement. The CTRAM design allows for preoperative planning for increasing alveolar ridge dimensions to support dental implants, reduces surgical time, and prevents the need for a second surgical site to gain sufficient alveolar ridge bone volume for dental implant therapy.

3D printing of an aortic aneurysm to facilitate decision making and device selection for endovascular aneurysm repair in complex neck anatomy.

PubMed

Tam, Matthew D B S; Laycock, Stephen D; Brown, James R I; Jakeways, Matthew

2013-12-01

To describe rapid prototyping or 3-dimensional (3D) printing of aneurysms with complex neck anatomy to facilitate endovascular aneurysm repair (EVAR). A 75-year-old man had a 6.6-cm infrarenal aortic aneurysm that appeared on computed tomographic angiography to have a sharp neck angulation of ~90°. However, although the computed tomography (CT) data were analyzed using centerline of flow, the true neck length and relations of the ostial origins were difficult to determine. No multidisciplinary consensus could be reached as to which stent-graft to use owing to these borderline features of the neck anatomy. Based on past experience with rapid prototyping technology, a decision was taken to print a model of the aneurysm to aid in visualization of the neck anatomy. The CT data were segmented, processed, and converted into a stereolithographic format representing the lumen as a 3D volume, from which a full-sized replica was printed within 24 hours. The model demonstrated that the neck was adequate for stent-graft repair using the Aorfix device. Rapid prototyping of aortic aneurysms is feasible and can aid decision making and device delivery. Further work is required to test the value of 3D replicas in planning procedures and their impact on procedure time, radiation dose, and procedure cost.

Fluoroscopic image-guided intervention system for transbronchial localization

NASA Astrophysics Data System (ADS)

Rai, Lav; Keast, Thomas M.; Wibowo, Henky; Yu, Kun-Chang; Draper, Jeffrey W.; Gibbs, Jason D.

2012-02-01

Reliable transbronchial access of peripheral lung lesions is desirable for the diagnosis and potential treatment of lung cancer. This procedure can be difficult, however, because accessory devices (e.g., needle or forceps) cannot be reliably localized while deployed. We present a fluoroscopic image-guided intervention (IGI) system for tracking such bronchoscopic accessories. Fluoroscopy, an imaging technology currently utilized by many bronchoscopists, has a fundamental shortcoming - many lung lesions are invisible in its images. Our IGI system aligns a digitally reconstructed radiograph (DRR) defined from a pre-operative computed tomography (CT) scan with live fluoroscopic images. Radiopaque accessory devices are readily apparent in fluoroscopic video, while lesions lacking a fluoroscopic signature but identifiable in the CT scan are superimposed in the scene. The IGI system processing steps consist of: (1) calibrating the fluoroscopic imaging system; (2) registering the CT anatomy with its depiction in the fluoroscopic scene; (3) optical tracking to continually update the DRR and target positions as the fluoroscope is moved about the patient. The end result is a continuous correlation of the DRR and projected targets with the anatomy depicted in the live fluoroscopic video feed. Because both targets and bronchoscopic devices are readily apparent in arbitrary fluoroscopic orientations, multiplane guidance is straightforward. The system tracks in real-time with no computational lag. We have measured a mean projected tracking accuracy of 1.0 mm in a phantom and present results from an in vivo animal study.

[Measurement of intracranial hematoma volume by personal computer].

PubMed

DU, Wanping; Tan, Lihua; Zhai, Ning; Zhou, Shunke; Wang, Rui; Xue, Gongshi; Xiao, An

2011-01-01

To explore the method for intracranial hematoma volume measurement by the personal computer. Forty cases of various intracranial hematomas were measured by the computer tomography with quantitative software and personal computer with Photoshop CS3 software, respectively. the data from the 2 methods were analyzed and compared. There was no difference between the data from the computer tomography and the personal computer (P>0.05). The personal computer with Photoshop CS3 software can measure the volume of various intracranial hematomas precisely, rapidly and simply. It should be recommended in the clinical medicolegal identification.

Computed Tomography of the Musculoskeletal System.

PubMed

Ballegeer, Elizabeth A

2016-05-01

Computed tomography (CT) has specific uses in veterinary species' appendicular musculoskeletal system. Parameters for acquisition of images, interpretation limitations, as well as published information regarding its use in small animals is reviewed. Copyright © 2016 Elsevier Inc. All rights reserved.

Cholangiocarcinoma associated with limbic encephalitis and early cerebral abnormalities detected by 2-deoxy-2-[fluorine-18]fluoro-D-glucose integrated with computed tomography-positron emission tomography: a case report.

PubMed

Schmidt, Sergio L; Schmidt, Juliana J; Tolentino, Julio C; Ferreira, Carlos G; de Almeida, Sergio A; Alvarenga, Regina P; Simoes, Eunice N; Schmidt, Guilherme J; Canedo, Nathalie H S; Chimelli, Leila

2016-07-20

Limbic encephalitis was originally described as a rare clinical neuropathological entity involving seizures and neuropsychological disturbances. In this report, we describe cerebral patterns visualized by positron emission tomography in a patient with limbic encephalitis and cholangiocarcinoma. To our knowledge, there is no other description in the literature of cerebral positron emission tomography findings in the setting of limbic encephalitis and subsequent diagnosis of cholangiocarcinoma. We describe a case of a 77-year-old Caucasian man who exhibited persistent cognitive changes 2 years before his death. A cerebral scan obtained at that time by 2-deoxy-2-[fluorine-18]fluoro- D -glucose integrated with computed tomography-positron emission tomography showed low radiotracer uptake in the frontal and temporal lobes. Cerebrospinal fluid analysis indicated the presence of voltage-gated potassium channel antibodies. Three months before the patient's death, a lymph node biopsy indicated a cholangiocarcinoma, and a new cerebral scan obtained by 2-deoxy-2-[fluorine-18]fluoro-D-glucose integrated with computed tomography-positron emission tomography showed an increment in the severity of metabolic deficit in the frontal and parietal lobes, as well as hypometabolism involving the temporal lobes. Two months before the patient's death, cerebral metastases were detected on a contrast-enhanced computed tomographic scan. Postmortem examination revealed a cholangiocarcinoma with multiple metastases including the lungs and lymph nodes. The patient's brain weighed 1300 g, and mild cortical atrophy, ex vacuo dilation of the ventricles, and mild focal thickening of the cerebellar leptomeninges, which were infiltrated by neoplastic epithelial cells, were observed. These findings support the need for continued vigilance in malignancy surveillance in patients with limbic encephalitis and early cerebral positron emission tomographic scan abnormalities. The difficulty in early diagnosis of small tumors, such as a cholangiocarcinoma, is discussed in the context of the clinical utility of early cerebral hypometabolism detected by 2-deoxy-2-[fluorine-18]fluoro-D-glucose integrated with computed tomography-positron emission tomography in patients with rapidly progressive dementia.

Intraoperative 3-Dimensional Computed Tomography and Navigation in Foot and Ankle Surgery.

PubMed

Chowdhary, Ashwin; Drittenbass, Lisca; Dubois-Ferrière, Victor; Stern, Richard; Assal, Mathieu

2016-09-01

Computer-assisted orthopedic surgery has developed dramatically during the past 2 decades. This article describes the use of intraoperative 3-dimensional computed tomography and navigation in foot and ankle surgery. Traditional imaging based on serial radiography or C-arm-based fluoroscopy does not provide simultaneous real-time 3-dimensional imaging, and thus leads to suboptimal visualization and guidance. Three-dimensional computed tomography allows for accurate intraoperative visualization of the position of bones and/or navigation implants. Such imaging and navigation helps to further reduce intraoperative complications, leads to improved surgical outcomes, and may become the gold standard in foot and ankle surgery. [Orthopedics.2016; 39(5):e1005-e1010.]. Copyright 2016, SLACK Incorporated.

Laparoendoscopic single-site repair of bladder rupture using a home-made single-port device: initial experience of treatment for a traumatic intraperitoneal bladder rupture.

PubMed

Lee, Joo Yong; Kang, Dong Hyuk; Lee, Seung Wook

2012-06-01

We report our initial experience with a laparoendoscopic single-site (LESS) repair of a bladder rupture using a home-made single-port device. A 37-year-old man presented to the emergency department with complaints of voiding difficulty and gross hematuria after blunt trauma. Cystography and computed tomography revealed an intraperitoneal bladder rupture. The patient underwent LESS repair of a bladder rupture using the Alexis wound retractor, which was inserted through the umbilical incision. A home-made single-port device was made by fixing 6½ surgical gloves to the outer rim of the retractor and securing the glove finger to the end of 3 trocars with a tie. Using the flexible laparoscopic instruments and rigid instruments, LESS surgery was performed using a procedure similar to conventional laparoscopic surgery. The patient did not have any voiding problem after removal of the urethral Foley catheter on the 10th postoperative day. To our knowledge, this is the first published report of LESS repair of a traumatic bladder rupture using a home-made single-port device in the literature.

Domain identification in impedance computed tomography by spline collocation method

NASA Technical Reports Server (NTRS)

Kojima, Fumio

1990-01-01

A method for estimating an unknown domain in elliptic boundary value problems is considered. The problem is formulated as an inverse problem of integral equations of the second kind. A computational method is developed using a splice collocation scheme. The results can be applied to the inverse problem of impedance computed tomography (ICT) for image reconstruction.

Fast optical transillumination tomography with large-size projection acquisition.

PubMed

Huang, Hsuan-Ming; Xia, Jinjun; Haidekker, Mark A

2008-10-01

Techniques such as optical coherence tomography and diffuse optical tomography have been shown to effectively image highly scattering samples such as tissue. An additional modality has received much less attention: Optical transillumination (OT) tomography, a modality that promises very high acquisition speed for volumetric scans. With the motivation to image tissue-engineered blood vessels for possible biomechanical testing, we have developed a fast OT device using a collimated, noncoherent beam with a large diameter together with a large-size CMOS camera that has the ability to acquire 3D projections in a single revolution of the sample. In addition, we used accelerated iterative reconstruction techniques to improve image reconstruction speed, while at the same time obtaining better image quality than through filtered backprojection. The device was tested using ink-filled polytetrafluorethylene tubes to determine geometric reconstruction accuracy and recovery of absorbance. Even in the presence of minor refractive index mismatch, the weighted error of the measured radius was <5% in all cases, and a high linear correlation of ink absorbance determined with a photospectrometer of R(2) = 0.99 was found, although the OT device systematically underestimated absorbance. Reconstruction time was improved from several hours (standard arithmetic reconstruction) to 90 s per slice with our optimized algorithm. Composed of only a light source, two spatial filters, a sample bath, and a CMOS camera, this device was extremely simple and cost-efficient to build.

Fast automatic segmentation of anatomical structures in x-ray computed tomography images to improve fluorescence molecular tomography reconstruction.

PubMed

Freyer, Marcus; Ale, Angelique; Schulz, Ralf B; Zientkowska, Marta; Ntziachristos, Vasilis; Englmeier, Karl-Hans

2010-01-01

The recent development of hybrid imaging scanners that integrate fluorescence molecular tomography (FMT) and x-ray computed tomography (XCT) allows the utilization of x-ray information as image priors for improving optical tomography reconstruction. To fully capitalize on this capacity, we consider a framework for the automatic and fast detection of different anatomic structures in murine XCT images. To accurately differentiate between different structures such as bone, lung, and heart, a combination of image processing steps including thresholding, seed growing, and signal detection are found to offer optimal segmentation performance. The algorithm and its utilization in an inverse FMT scheme that uses priors is demonstrated on mouse images.

A Tunable Silk Hydrogel Device for Studying Limb Regeneration in Adult Xenopus Laevis

PubMed Central

Golding, Anne; Levin, Michael; Kaplan, David L.

2016-01-01

In certain amphibian models limb regeneration can be promoted or inhibited by the local wound bed environment. This research introduces a device that can be utilized as an experimental tool to characterize the conditions that promotes limb regeneration in the adult frog (Xenopus laevis) model. In particular, this device was designed to manipulate the local wound environment via a hydrogel insert. Initial characterization of the hydrogel insert revealed that this interaction had a significant influence on mechanical forces to the animal, due to the contraction of the hydrogel. The material and mechanical properties of the hydrogel insert were a factor in the device design in relation to the comfort of the animal and the ability to effectively manipulate the amputation site. The tunable features of the hydrogel were important in determining the pro-regenerative effects in limb regeneration, which was measured by cartilage spike formation and quantified by micro-computed tomography. The hydrogel insert was a factor in the observed morphological outcomes following amputation. Future work will focus on characterizing and optimizing the device’s observed capability to manipulate biological pathways that are essential for limb regeneration. However, the present work provides a framework for the role of a hydrogel in the device and a path forward for more systematic studies. PMID:27257960

Atlantoaxial Joint Distraction with a New Expandable Device for the Treatment of Basilar Invagination with Preservation of the C2 Nerve Root: A Cadaveric Anatomical Study.

PubMed

Polli, Filippo Maria; Trungu, Sokol; Miscusi, Massimo; Forcato, Stefano; Visocchi, Massimiliano; Raco, Antonino

2017-01-01

Atlantoaxial joint distraction has been advocated for the decompression of the brain stem in patients affected by basilar invagination, avoiding direct transoral decompression. This technique requires C2 ganglion resection and it is often impossible to perform due to the peculiar bony anatomy. We describe a cadaveric anatomical study supporting the feasibility of C1-C2 distraction performed with an expandable device, allowing easier insertion of the tool and preservation of the C2 nerve root. In five adult cadaveric specimens, posterior atlantoaxial surgical exposure was performed and an expandable system was inserted within the C1-C2 joint. The expansion of the device, leading to active distraction of the joint space, together with all the surgical steps of the technique was recorded with anatomical pictures and the final results were checked with a computed tomography (CT) scan. Insertion of the device was easily performed in all cases without anatomical conflict with the C2 ganglion; CT scans confirmed the distraction of the C1-C2 joint. This cadaveric anatomical study confirms the feasibility of the introduction of an expandable and flexible device within the C1-C2 joint, allowing it's distraction and preservation of the C2 ganglion.

Exploratory Application of Augmented Reality/Mixed Reality Devices for Acute Care Procedure Training.

PubMed

Kobayashi, Leo; Zhang, Xiao Chi; Collins, Scott A; Karim, Naz; Merck, Derek L

2018-01-01

Augmented reality (AR), mixed reality (MR), and virtual reality devices are enabling technologies that may facilitate effective communication in healthcare between those with information and knowledge (clinician/specialist; expert; educator) and those seeking understanding and insight (patient/family; non-expert; learner). Investigators initiated an exploratory program to enable the study of AR/MR use-cases in acute care clinical and instructional settings. Academic clinician educators, computer scientists, and diagnostic imaging specialists conducted a proof-of-concept project to 1) implement a core holoimaging pipeline infrastructure and open-access repository at the study institution, and 2) use novel AR/MR techniques on off-the-shelf devices with holoimages generated by the infrastructure to demonstrate their potential role in the instructive communication of complex medical information. The study team successfully developed a medical holoimaging infrastructure methodology to identify, retrieve, and manipulate real patients' de-identified computed tomography and magnetic resonance imagesets for rendering, packaging, transfer, and display of modular holoimages onto AR/MR headset devices and connected displays. Holoimages containing key segmentations of cervical and thoracic anatomic structures and pathology were overlaid and registered onto physical task trainers for simulation-based "blind insertion" invasive procedural training. During the session, learners experienced and used task-relevant anatomic holoimages for central venous catheter and tube thoracostomy insertion training with enhanced visual cues and haptic feedback. Direct instructor access into the learner's AR/MR headset view of the task trainer was achieved for visual-axis interactive instructional guidance. Investigators implemented a core holoimaging pipeline infrastructure and modular open-access repository to generate and enable access to modular holoimages during exploratory pilot stage applications for invasive procedure training that featured innovative AR/MR techniques on off-the-shelf headset devices.

Exploratory Application of Augmented Reality/Mixed Reality Devices for Acute Care Procedure Training

PubMed Central

Kobayashi, Leo; Zhang, Xiao Chi; Collins, Scott A.; Karim, Naz; Merck, Derek L.

2018-01-01

Introduction Augmented reality (AR), mixed reality (MR), and virtual reality devices are enabling technologies that may facilitate effective communication in healthcare between those with information and knowledge (clinician/specialist; expert; educator) and those seeking understanding and insight (patient/family; non-expert; learner). Investigators initiated an exploratory program to enable the study of AR/MR use-cases in acute care clinical and instructional settings. Methods Academic clinician educators, computer scientists, and diagnostic imaging specialists conducted a proof-of-concept project to 1) implement a core holoimaging pipeline infrastructure and open-access repository at the study institution, and 2) use novel AR/MR techniques on off-the-shelf devices with holoimages generated by the infrastructure to demonstrate their potential role in the instructive communication of complex medical information. Results The study team successfully developed a medical holoimaging infrastructure methodology to identify, retrieve, and manipulate real patients’ de-identified computed tomography and magnetic resonance imagesets for rendering, packaging, transfer, and display of modular holoimages onto AR/MR headset devices and connected displays. Holoimages containing key segmentations of cervical and thoracic anatomic structures and pathology were overlaid and registered onto physical task trainers for simulation-based “blind insertion” invasive procedural training. During the session, learners experienced and used task-relevant anatomic holoimages for central venous catheter and tube thoracostomy insertion training with enhanced visual cues and haptic feedback. Direct instructor access into the learner’s AR/MR headset view of the task trainer was achieved for visual-axis interactive instructional guidance. Conclusion Investigators implemented a core holoimaging pipeline infrastructure and modular open-access repository to generate and enable access to modular holoimages during exploratory pilot stage applications for invasive procedure training that featured innovative AR/MR techniques on off-the-shelf headset devices. PMID:29383074

Clinical applications of cone beam computed tomography in endodontics: A comprehensive review.

PubMed

Cohenca, Nestor; Shemesh, Hagay

2015-09-01

The use of cone beam computed tomography (CBCT) in endodontics has been extensively reported in the literature. Compared with the traditional spiral computed tomography, limited field of view (FOV) CBCT results in a fraction of the effective absorbed dose of radiation. The purpose of this manuscript is to review the application and advantages associated with advanced endodontic problems and complications, while reducing radiation exposure during complex endodontic procedures. The benefits of the added diagnostic information provided by intraoperative CBCT images in select cases justify the risk associated with the limited level of radiation exposure.

Dry coupling for whole-body small-animal photoacoustic computed tomography

NASA Astrophysics Data System (ADS)

Yeh, Chenghung; Li, Lei; Zhu, Liren; Xia, Jun; Li, Chiye; Chen, Wanyi; Garcia-Uribe, Alejandro; Maslov, Konstantin I.; Wang, Lihong V.

2017-04-01

We have enhanced photoacoustic computed tomography with dry acoustic coupling that eliminates water immersion anxiety and wrinkling of the animal and facilitates incorporating complementary modalities and procedures. The dry acoustic coupler is made of a tubular elastic membrane enclosed by a closed transparent water tank. The tubular membrane ensures water-free contact with the animal, and the closed water tank allows pressurization for animal stabilization. The dry coupler was tested using a whole-body small-animal ring-shaped photoacoustic computed tomography system. Dry coupling was found to provide image quality comparable to that of conventional water coupling.

Linear-array based full-view high-resolution photoacoustic computed tomography of whole mouse brain functions in vivo

NASA Astrophysics Data System (ADS)

Li, Lei; Zhang, Pengfei; Wang, Lihong V.

2018-02-01

Photoacoustic computed tomography (PACT) is a non-invasive imaging technique offering high contrast, high resolution, and deep penetration in biological tissues. We report a photoacoustic computed tomography (PACT) system equipped with a high frequency linear array for anatomical and functional imaging of the mouse whole brain. The linear array was rotationally scanned in the coronal plane to achieve the full-view coverage. We investigated spontaneous neural activities in the deep brain by monitoring the hemodynamics and observed strong interhemispherical correlations between contralateral regions, both in the cortical layer and in the deep regions.

Broadband Terahertz Computed Tomography Using a 5k-pixel Real-time THz Camera

NASA Astrophysics Data System (ADS)

Trichopoulos, Georgios C.; Sertel, Kubilay

2015-07-01

We present a novel THz computed tomography system that enables fast 3-dimensional imaging and spectroscopy in the 0.6-1.2 THz band. The system is based on a new real-time broadband THz camera that enables rapid acquisition of multiple cross-sectional images required in computed tomography. Tomographic reconstruction is achieved using digital images from the densely-packed large-format (80×64) focal plane array sensor located behind a hyper-hemispherical silicon lens. Each pixel of the sensor array consists of an 85 μm × 92 μm lithographically fabricated wideband dual-slot antenna, monolithically integrated with an ultra-fast diode tuned to operate in the 0.6-1.2 THz regime. Concurrently, optimum impedance matching was implemented for maximum pixel sensitivity, enabling 5 frames-per-second image acquisition speed. As such, the THz computed tomography system generates diffraction-limited resolution cross-section images as well as the three-dimensional models of various opaque and partially transparent objects. As an example, an over-the-counter vitamin supplement pill is imaged and its material composition is reconstructed. The new THz camera enables, for the first time, a practical application of THz computed tomography for non-destructive evaluation and biomedical imaging.

[Contribution of X-ray computed tomography in the evaluation of kidney performance].

PubMed

Lemoine, Sandrine; Rognant, Nicolas; Collet-Benzaquen, Diane; Juillard, Laurent

2012-07-01

X-ray computer assisted tomography scanner is an imaging method based on the use of X-ray attenuation in tissue. This attenuation is proportional to the density of the tissue (without or after contrast media injection) in each pixel image of the image. Spiral scanner, the electron beam computed tomography (EBCT) scanner and multidetector computed tomography scanner allow renal anatomical measurements, such as cortical and medullary volume, but also the measurement of renal functional parameters, such as regional renal perfusion, renal blood flow and glomerular filtration rate. These functional parameters are extracted from the modeling of the kinetics of the contrast media concentration in the vascular space and the renal tissue, using two main mathematical models (the gamma variate model and the Patlak model). Renal functional imaging allows measuring quantitative parameters on each kidney separately, in a non-invasive manner, providing significant opportunities in nephrology, both for experimental and clinical studies. However, this method uses contrast media that may alter renal function, thus limiting its use in patients with chronic renal failure. Moreover, the increase irradiation delivered to the patient with multi detector computed tomography (MDCT) should be considered. Copyright © 2011 Association Société de néphrologie. Published by Elsevier SAS. All rights reserved.

Practical characterization of quantum devices without tomography

NASA Astrophysics Data System (ADS)

Landon-Cardinal, Olivier; Flammia, Steven; Silva, Marcus; Liu, Yi-Kai; Poulin, David

2012-02-01

Quantum tomography is the main method used to assess the quality of quantum information processing devices, but its complexity presents a major obstacle for the characterization of even moderately large systems. Part of the reason for this complexity is that tomography generates much more information than is usually sought. Taking a more targeted approach, we develop schemes that enable (i) estimating the ?delity of an experiment to a theoretical ideal description, (ii) learning which description within a reduced subset best matches the experimental data. Both these approaches yield a signi?cant reduction in resources compared to tomography. In particular, we show how to estimate the ?delity between a predicted pure state and an arbitrary experimental state using only a constant number of Pauli expectation values selected at random according to an importance-weighting rule. In addition, we propose methods for certifying quantum circuits and learning continuous-time quantum dynamics that are described by local Hamiltonians or Lindbladians.

Pulse X-ray device for stereo imaging and few-projection tomography of explosive and fast processes

NASA Astrophysics Data System (ADS)

Palchikov, E. I.; Dolgikh, A. V.; Klypin, V. V.; Krasnikov, I. Y.; Ryabchun, A. M.

2017-10-01

This paper describes the operation principles and design features of the device for single pulse X-raying of explosive and high-speed processes, developed on the basis of a Tesla transformer with lumped secondary capacitor bank. The circuit with the lumped capacitor bank allows transferring a greater amount of energy to the discharge circuit as compared with the Marks-surge generator for more effective operation with remote X-ray tubes connected by coaxial cables. The device equipped with multiple X-ray tubes provides simultaneous X-raying of extended or spaced objects, stereo imaging, or few-projection tomography.

Syringeless power injector versus dual-syringe power injector: economic evaluation of user performance, the impact on contrast enhanced computed tomography (CECT) workflow exams, and hospital costs.

PubMed

Colombo, Giorgio L; Andreis, Ivo A Bergamo; Di Matteo, Sergio; Bruno, Giacomo M; Mondellini, Claudio

2013-01-01

The utilization of diagnostic imaging has substantially increased over the past decade in Europe and North America and continues to grow worldwide. The purpose of this study was to develop an economic evaluation of a syringeless power injector (PI) versus a dual-syringe PI for contrast enhanced computed tomography (CECT) in a hospital setting. Patients (n=2379) were enrolled at the Legnano Hospital between November 2012 and January 2013. They had been referred to the hospital for a CECT analysis and were randomized into two groups. The first group was examined with a 256-MDCT (MultiDetector Computed Tomography) scanner using a syringeless power injector, while the other group was examined with a 64-MDCT scanner using a dual-syringe. Data on the operators' time required in the patient analysis steps as well as on the quantity of consumable materials used were collected. The radiologic technologists' satisfaction with the use of the PIs was rated on a 10-point scale. A budget impact analysis and sensitivity analysis were performed under the base-case scenario. A total of 1,040 patients were examined using the syringeless system, and 1,339 with the dual-syringe system; the CECT examination quality was comparable for both PI systems. Equipment preparation time and releasing time per examination for syringeless PIs versus dual-syringe PIs were 100±30 versus 180±30 seconds and 90±30 and 140±20 seconds, respectively. On average, 10±3 mL of contrast media (CM) wastage per examination was observed with the dual-syringe PI and 0±1 mL with the syringeless PI. Technologists had higher satisfaction with the syringeless PI than with the dual-syringe system (8.8 versus 8.0). The syringeless PI allows a saving of about €6.18 per patient, both due to the lower cost of the devices and to the better performance of the syringeless system. The univariate sensitivity analysis carried out on the base-case results within the standard deviation range confirmed the saving generated by using the syringeless device, with saving values between €5.40 and €6.20 per patient. The syringeless PI was found to be more user-friendly and efficient, minimizing contrast wastage and providing similar contrast enhancement quality compared to the dual-syringe injector, with comparable CECT examination quality.

Inter- and intraobserver reliability of the vertebral, local and segmental kyphosis in 120 traumatic lumbar and thoracic burst fractures: evaluation in lateral X-rays and sagittal computed tomographies

PubMed Central

Brunner, Alexander; Gühring, Markus; Schmälzle, Traude; Weise, Kuno; Badke, Andreas

2009-01-01

Evaluation of the kyphosis angle in thoracic and lumbar burst fractures is often used to indicate surgical procedures. The kyphosis angle could be measured as vertebral, segmental and local kyphosis according to the method of Cobb. The vertebral, segmental and local kyphosis according to the method of Cobb were measured at 120 lateral X-rays and sagittal computed tomographies of 60 thoracic and 60 lumbar burst fractures by 3 independent observers on 2 separate occasions. Osteoporotic fractures were excluded. The intra- and interobserver reliability of these angles in X-ray and computed tomogram, using the intra class correlation coefficient (ICC) were evaluated. Highest reproducibility showed the segmental kyphosis followed by the vertebral kyphosis. For thoracic fractures segmental kyphosis shows in X-ray “excellent” inter- and intraobserver reliabilities (ICC 0.826, 0.802) and for lumbar fractures “good” to “excellent” inter- and intraobserver reliabilities (ICC = 0.790, 0.803). In computed tomography, the segmental kyphosis showed “excellent” inter- and intraobserver reliabilities (ICC = 0.824, 0.801) for thoracic and “excellent” inter- and intraobserver reliabilities (ICC = 0.874, 0.835) for the lumbar fractures. Regarding both diagnostic work ups (X-ray and computed tomography), significant differences were evaluated in interobserver reliabilities for vertebral kyphosis measured in lumbar fracture X-rays (p = 0.035) and interobserver reliabilities for local kyphosis, measured in thoracic fracture X-rays (p = 0.010). Regarding both fracture localizations (thoracic and lumbar fractures), significant differences could only be evaluated in interobserver reliabilities for the local kyphosis measured in computed tomographies (p = 0.045) and in intraobserver reliabilities for the vertebral kyphosis measured in X-rays (p = 0.024). “Good” to “excellent” inter- and intraobserver reliabilities for vertebral, segmental and local kyphosis in X-ray make these angles to a helpful tool, indicating surgical procedures. For the practical use in lateral X-ray, we emphasize the determination of the segmental kyphosis, because of the highest reproducibility of this angle. “Good” to “excellent” inter- and intraobserver reliabilities for these three angles could also be evaluated in computed tomographies. Therefore, also in computed tomography, the use of these three angles seems to be generally possible. For a direct correlation of the results in lateral X-ray and in computed tomography, further studies should be needed. PMID:19953277

Contribution of computed tomography to the investigation of La Tene culture iron artefacts

NASA Astrophysics Data System (ADS)

Vopálenský, M.; Sankot, P.; Fořt, M.; Kumpová, I.; Vavřík, D.

2017-07-01

The X-ray tomographic study was realized in addition to the standard X-ray radiography for the purpose of the new conservation work upon the La Tene culture iron artifacts from the collections of the National Museum in Prague. These artifacts are heavily damaged by the corrosion, avoiding thus an effective visual exploration. The work shows that even details, which are shallow compared to the artifact thickness and therefore not detectable in standard radiographic images, can be made visible in 3D models obtained tomografically. The tomographic data acquisition was performed utilizing the unique TORATOM device, equipped with a large area X-ray detector with Gadox scintillator. The tomographic reconstruction revealed insufficiencies in the earlier conservation processes of the La Tene culture swords, as well as so-far unknown details, such as the exact sword shapes and their decoration. These new findings allowed better classifying of the artifacts. Tomography also helped in visualizing details of iron clips that are completely hidden under the rust, making thus the technology of the clip formation clearly observable. With this work, it has been proven that tomography can bear valuable new information compared to the standard X-ray radiography commonly used in the investigation of iron archeological artifacts.

Dipyridamole stress myocardial perfusion by computed tomography in patients with left bundle branch block.

PubMed

Cabeda, Estêvan Vieira; Falcão, Andréa Maria Gomes; Soares, José; Rochitte, Carlos Eduardo; Nomura, César Higa; Ávila, Luiz Francisco Rodrigues; Parga, José Rodrigues

2015-12-01

Functional tests have limited accuracy for identifying myocardial ischemia in patients with left bundle branch block (LBBB). To assess the diagnostic accuracy of dipyridamole-stress myocardial computed tomography perfusion (CTP) by 320-detector CT in patients with LBBB using invasive quantitative coronary angiography (QCA) (stenosis ≥ 70%) as reference; to investigate the advantage of adding CTP to coronary computed tomography angiography (CTA) and compare the results with those of single photon emission computed tomography (SPECT) myocardial perfusion scintigraphy. Thirty patients with LBBB who had undergone SPECT for the investigation of coronary artery disease were referred for stress tomography. Independent examiners performed per-patient and per-coronary territory assessments. All patients gave written informed consent to participate in the study that was approved by the institution's ethics committee. The patients' mean age was 62 ± 10 years. The mean dose of radiation for the tomography protocol was 9.3 ± 4.6 mSv. With regard to CTP, the per-patient values for sensitivity, specificity, positive and negative predictive values, and accuracy were 86%, 81%, 80%, 87%, and 83%, respectively (p = 0.001). The per-territory values were 63%, 86%, 65%, 84%, and 79%, respectively (p < 0.001). In both analyses, the addition of CTP to CTA achieved higher diagnostic accuracy for detecting myocardial ischemia than SPECT (p < 0.001). The use of the stress tomography protocol is feasible and has good diagnostic accuracy for assessing myocardial ischemia in patients with LBBB.

Case of colonic intussusception secondary to mobile cecum syndrome repaired by laparoscopic cecopexy using a barbed wound suture device.

PubMed

Yamamoto, Tetsu; Tajima, Yoshitsugu; Hyakudomi, Ryoji; Hirayama, Takanori; Taniura, Takahito; Ishitobi, Kazunari; Hirahara, Noriyuki

2017-09-21

A 27-year-old man with recurrent right lower quadrant pain was admitted to our hospital. Ultrasonography and computed tomography examination of the abdomen revealed a target sign in the ascending colon, which was compatible with the diagnosis of cecal intussusception. The intussusception was spontaneously resolved at that time, but it relapsed 6 mo later. The patient underwent a successful colonoscopic disinvagination; there was no evidence of neoplastic or inflammatory lesions in the colon and terminal ileum. The patient underwent laparoscopic surgery for recurring cecal intussusception. During laparoscopy, we observed an unfixed cecum on the posterior peritoneum (i.e. a mobile cecum). Thus, we performed laparoscopic appendectomy and cecopexy with a lateral peritoneal flap using a barbed wound suture device. The patient's post-operative course was uneventful, and he continued to do well without recurrence at 10 mo after surgery. Laparoscopic cecopexy using a barbed wound suture device is a simple and reliable procedure that can be the treatment of choice for recurrent cecal intussusception associated with a mobile cecum.

The Influence of Internal Structures in Fused Deposition Modeling Method on Dimensional Accuracy of Components

NASA Astrophysics Data System (ADS)

Milde, Ján; Morovič, Ladislav

2016-09-01

The paper investigates the influence of infill (internal structures of components) in the Fused Deposition Modeling (FDM) method on dimensional and geometrical accuracy of components. The components in this case were real models of human mandible, which were obtained by Computed Tomography (CT) mostly used in medical applications. In the production phase, the device used for manufacturing, was a 3D printer Zortrax M200 based on the FDM technology. In the second phase, the mandibles made by the printer, were digitized using optical scanning device of GOM ATOS Triple Scan II. They were subsequently evaluated in the final phase. The practical part of this article describes the procedure of jaw model modification, the production of components using a 3D printer, the procedure of digitization of printed parts by optical scanning device and the procedure of comparison. The outcome of this article is a comparative analysis of individual printed parts, containing tables with mean deviations for individual printed parts, as well as tables for groups of printed parts with the same infill parameter.

Role of positron emission tomography/computed tomography in breast cancer.

PubMed

Bourgeois, Austin C; Warren, Lance A; Chang, Ted T; Embry, Scott; Hudson, Kathleen; Bradley, Yong C

2013-09-01

Although positron emission tomography (PET) imaging may not be used in the diagnosis of breast cancer, the use of PET/computed tomography is imperative in all aspects of breast cancer staging, treatment, and follow-up. PET will continue to be relevant in personalized medicine because accurate tumor status will be even more critical during and after the transition from a generic metabolic agent to receptor imaging. Positron emission mammography is an imaging proposition that may have benefits in lower doses, but its use is limited without new radiopharmaceuticals. Copyright © 2013 Elsevier Inc. All rights reserved.

Transurethral Ultrasound Diffraction Tomography

DTIC Science & Technology

2007-03-01

the covariance matrix was derived. The covariance reduced to that of the X- ray CT under the assumptions of linear operator and real data.[5] The...the covariance matrix in the linear x- ray computed tomography is a special case of the inverse scattering matrix derived in this paper. The matrix was...is derived in Sec. IV, and its relation to that of the linear x- ray computed tomography appears in Sec. V. In Sec. VI, the inverse scattering

Fast attainment of computer cursor control with noninvasively acquired brain signals

NASA Astrophysics Data System (ADS)

Bradberry, Trent J.; Gentili, Rodolphe J.; Contreras-Vidal, José L.

2011-06-01

Brain-computer interface (BCI) systems are allowing humans and non-human primates to drive prosthetic devices such as computer cursors and artificial arms with just their thoughts. Invasive BCI systems acquire neural signals with intracranial or subdural electrodes, while noninvasive BCI systems typically acquire neural signals with scalp electroencephalography (EEG). Some drawbacks of invasive BCI systems are the inherent risks of surgery and gradual degradation of signal integrity. A limitation of noninvasive BCI systems for two-dimensional control of a cursor, in particular those based on sensorimotor rhythms, is the lengthy training time required by users to achieve satisfactory performance. Here we describe a novel approach to continuously decoding imagined movements from EEG signals in a BCI experiment with reduced training time. We demonstrate that, using our noninvasive BCI system and observational learning, subjects were able to accomplish two-dimensional control of a cursor with performance levels comparable to those of invasive BCI systems. Compared to other studies of noninvasive BCI systems, training time was substantially reduced, requiring only a single session of decoder calibration (~20 min) and subject practice (~20 min). In addition, we used standardized low-resolution brain electromagnetic tomography to reveal that the neural sources that encoded observed cursor movement may implicate a human mirror neuron system. These findings offer the potential to continuously control complex devices such as robotic arms with one's mind without lengthy training or surgery.

APPLICATION OF COMPUTER AIDED TOMOGRAPHY (CAT) TO THE STUDY OF MARINE BENTIC COMMUNITIES

EPA Science Inventory

Sediment cores were imaged using a Computer-Aided Tomography (CT) scanner at Massachusetts General Hospital, Boston, Massachusetts, United States. Procedures were developed, using the attenuation of X-rays, to differentiate between sediment and the water contained in macrobenthic...

How to interpret computed tomography of the lumbar spine

PubMed Central

Mobasheri, R; Das, T; Vaidya, S; Mallik, S; El-Hussainy, M; Casey, A

2014-01-01

Computed tomography (CT) of the spine has remained an important tool in the investigation of spinal pathology. This article helps to explain the basics of CT of the lumbar spine to allow the clinician better use of this diagnostic tool. PMID:25245727

Clinical and computed tomography features of secondary renal hyperparathyroidism

PubMed Central

Vanbrugghe, Benoît; Blond, Laurent; Carioto, Lisa; Carmel, Eric Norman; Nadeau, Marie-Eve

2011-01-01

An atypical case of secondary renal hyperparathyroidism was diagnosed in a 9-year-old miniature schnauzer after a skull computed tomography (CT) showed the presence of 2 bilateral and symmetrical soft tissue maxillary masses, and osteopenia of the skull. PMID:21532826

Peri-implant assessment via cone beam computed tomography and digital periapical radiography: an ex vivo study.

PubMed

Silveira-Neto, Nicolau; Flores, Mateus Ericson; De Carli, João Paulo; Costa, Max Dória; Matos, Felipe de Souza; Paranhos, Luiz Renato; Linden, Maria Salete Sandini

2017-11-01

This research evaluated detail registration in peri-implant bone using two different cone beam computer tomography systems and a digital periapical radiograph. Three different image acquisition protocols were established for each cone beam computer tomography apparatus, and three clinical situations were simulated in an ex vivo fresh pig mandible: buccal bone defect, peri-implant bone defect, and bone contact. Data were subjected to two analyses: quantitative and qualitative. The quantitative analyses involved a comparison of real specimen measures using a digital caliper in three regions of the preserved buccal bone - A, B and E (control group) - to cone beam computer tomography images obtained with different protocols (kp1, kp2, kp3, ip1, ip2, and ip3). In the qualitative analyses, the ability to register peri-implant details via tomography and digital periapical radiography was verified, as indicated by twelve evaluators. Data were analyzed with ANOVA and Tukey's test (α=0.05). The quantitative assessment showed means statistically equal to those of the control group under the following conditions: buccal bone defect B and E with kp1 and ip1, peri-implant bone defect E with kp2 and kp3, and bone contact A with kp1, kp2, kp3, and ip2. Qualitatively, only bone contacts were significantly different among the assessments, and the p3 results differed from the p1 and p2 results. The other results were statistically equivalent. The registration of peri-implant details was influenced by the image acquisition protocol, although metal artifacts were produced in all situations. The evaluators preferred the Kodak 9000 3D cone beam computer tomography in most cases. The evaluators identified buccal bone defects better with cone beam computer tomography and identified peri-implant bone defects better with digital periapical radiography.

Use of magnetic tomography technology to evaluate dowel placement

DOT National Transportation Integrated Search

2005-11-01

Extensive laboratory and field evaluations were conducted under this project to evaluate the effectiveness and limitations of the MIT Scan-2 device, which uses magnetic tomography technology to evaluate the placement of metal dowel bars in concrete p...

System design for 3D wound imaging using low-cost mobile devices

NASA Astrophysics Data System (ADS)

Sirazitdinova, Ekaterina; Deserno, Thomas M.

2017-03-01

The state-of-the art method of wound assessment is a manual, imprecise and time-consuming procedure. Per- formed by clinicians, it has limited reproducibility and accuracy, large time consumption and high costs. Novel technologies such as laser scanning microscopy, multi-photon microscopy, optical coherence tomography and hyper-spectral imaging, as well as devices relying on the structured light sensors, make accurate wound assessment possible. However, such methods have limitations due to high costs and may lack portability and availability. In this paper, we present a low-cost wound assessment system and architecture for fast and accurate cutaneous wound assessment using inexpensive consumer smartphone devices. Computer vision techniques are applied either on the device or the server to reconstruct wounds in 3D as dense models, which are generated from images taken with a built-in single camera of a smartphone device. The system architecture includes imaging (smartphone), processing (smartphone or PACS) and storage (PACS) devices. It supports tracking over time by alignment of 3D models, color correction using a reference color card placed into the scene and automatic segmentation of wound regions. Using our system, we are able to detect and document quantitative characteristics of chronic wounds, including size, depth, volume, rate of healing, as well as qualitative characteristics as color, presence of necrosis and type of involved tissue.

Single-Photon Emission Computed Tomography/Computed Tomography Imaging in a Rabbit Model of Emphysema Reveals Ongoing Apoptosis In Vivo

PubMed Central

Goldklang, Monica P.; Tekabe, Yared; Zelonina, Tina; Trischler, Jordis; Xiao, Rui; Stearns, Kyle; Romanov, Alexander; Muzio, Valeria; Shiomi, Takayuki; Johnson, Lynne L.

2016-01-01

Evaluation of lung disease is limited by the inability to visualize ongoing pathological processes. Molecular imaging that targets cellular processes related to disease pathogenesis has the potential to assess disease activity over time to allow intervention before lung destruction. Because apoptosis is a critical component of lung damage in emphysema, a functional imaging approach was taken to determine if targeting apoptosis in a smoke exposure model would allow the quantification of early lung damage in vivo. Rabbits were exposed to cigarette smoke for 4 or 16 weeks and underwent single-photon emission computed tomography/computed tomography scanning using technetium-99m–rhAnnexin V-128. Imaging results were correlated with ex vivo tissue analysis to validate the presence of lung destruction and apoptosis. Lung computed tomography scans of long-term smoke–exposed rabbits exhibit anatomical similarities to human emphysema, with increased lung volumes compared with controls. Morphometry on lung tissue confirmed increased mean linear intercept and destructive index at 16 weeks of smoke exposure and compliance measurements documented physiological changes of emphysema. Tissue and lavage analysis displayed the hallmarks of smoke exposure, including increased tissue cellularity and protease activity. Technetium-99m–rhAnnexin V-128 single-photon emission computed tomography signal was increased after smoke exposure at 4 and 16 weeks, with confirmation of increased apoptosis through terminal deoxynucleotidyl transferase dUTP nick end labeling staining and increased tissue neutral sphingomyelinase activity in the tissue. These studies not only describe a novel emphysema model for use with future therapeutic applications, but, most importantly, also characterize a promising imaging modality that identifies ongoing destructive cellular processes within the lung. PMID:27483341

Quantitative X-ray fluorescence computed tomography for low-Z samples using an iterative absorption correction algorithm

NASA Astrophysics Data System (ADS)

Huang, Rong; Limburg, Karin; Rohtla, Mehis

2017-05-01

X-ray fluorescence computed tomography is often used to measure trace element distributions within low-Z samples, using algorithms capable of X-ray absorption correction when sample self-absorption is not negligible. Its reconstruction is more complicated compared to transmission tomography, and therefore not widely used. We describe in this paper a very practical iterative method that uses widely available transmission tomography reconstruction software for fluorescence tomography. With this method, sample self-absorption can be corrected not only for the absorption within the measured layer but also for the absorption by material beyond that layer. By combining tomography with analysis for scanning X-ray fluorescence microscopy, absolute concentrations of trace elements can be obtained. By using widely shared software, we not only minimized the coding, took advantage of computing efficiency of fast Fourier transform in transmission tomography software, but also thereby accessed well-developed data processing tools coming with well-known and reliable software packages. The convergence of the iterations was also carefully studied for fluorescence of different attenuation lengths. As an example, fish eye lenses could provide valuable information about fish life-history and endured environmental conditions. Given the lens's spherical shape and sometimes the short distance from sample to detector for detecting low concentration trace elements, its tomography data are affected by absorption related to material beyond the measured layer but can be reconstructed well with our method. Fish eye lens tomography results are compared with sliced lens 2D fluorescence mapping with good agreement, and with tomography providing better spatial resolution.

A hierarchical storage management (HSM) scheme for cost-effective on-line archival using lossy compression.

PubMed

Avrin, D E; Andriole, K P; Yin, L; Gould, R G; Arenson, R L

2001-03-01

A hierarchical storage management (HSM) scheme for cost-effective on-line archival of image data using lossy compression is described. This HSM scheme also provides an off-site tape backup mechanism and disaster recovery. The full-resolution image data are viewed originally for primary diagnosis, then losslessly compressed and sent off site to a tape backup archive. In addition, the original data are wavelet lossy compressed (at approximately 25:1 for computed radiography, 10:1 for computed tomography, and 5:1 for magnetic resonance) and stored on a large RAID device for maximum cost-effective, on-line storage and immediate retrieval of images for review and comparison. This HSM scheme provides a solution to 4 problems in image archiving, namely cost-effective on-line storage, disaster recovery of data, off-site tape backup for the legal record, and maximum intermediate storage and retrieval through the use of on-site lossy compression.

A guide to SPECT equipment for brain imaging

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

Hoffer, P.B.; Zubal, G.

1991-12-31

Single photon emission computed tomography (SPECT) was started by Kuhl and Edwards about 30 years ago. Their original instrument consisted of four focused Nal probes mounted on a moving gantry. During the 1980s, clinical SPECT imaging was most frequently performed using single-headed Anger-type cameras which were modified for rotational as well as static imaging. Such instruments are still available and may be useful in settings where there are few patients and SPECT is used only occasionally. More frequently, however, dedicated SPECT devices are purchased which optimize equipment potential while being user-friendly. Modern SPECT instrumentation incorporates improvements in the detector, computers,more » mathematical formulations, electronics and display systems. A comprehensive discussion of all aspects of SPECT is beyond the scope of this article. The authors, however, discuss general concepts of SPECT, the current state-of-the-art in clinical SPECT instrumentation, and areas of common misunderstanding. 9 refs.« less

A System for Seismocardiography-Based Identification of Quiescent Heart Phases: Implications for Cardiac Imaging

PubMed Central

Wick, Carson A.; Su, Jin-Jyh; McClellan, James H.; Brand, Oliver; Bhatti, Pamela T.; Buice, Ashley L.; Stillman, Arthur E.; Tang, Xiangyang; Tridandapani, Srini

2013-01-01

Seismocardiography (SCG), a representation of mechanical heart motion, may more accurately determine periods of cardiac quiescence within a cardiac cycle than the electrically derived electrocardiogram (EKG) and, thus, may have implications for gating in cardiac computed tomography. We designed and implemented a system to synchronously acquire echocardiography, EKG, and SCG data. The device was used to study the variability between EKG and SCG and characterize the relationship between the mechanical and electrical activity of the heart. For each cardiac cycle, the feature of the SCG indicating Aortic Valve Closure was identified and its time position with respect to the EKG was observed. This position was found to vary for different heart rates and between two human subjects. A color map showing the magnitude of the SCG acceleration and computed velocity was derived, allowing for direct visualization of quiescent phases of the cardiac cycle with respect to heart rate. PMID:22581141

Correlation of computed tomography, magnetic resonance imaging and clinical outcome in acute carbon monoxide poisoning.

PubMed

Ozcan, Namik; Ozcam, Giray; Kosar, Pinar; Ozcan, Ayse; Basar, Hulya; Kaymak, Cetin

2016-01-01

Carbon monoxide is a toxic gas for humans and is still a silent killer in both developed and developing countries. The aim of this case series was to evaluate early radiological images as a predictor of subsequent neuropsychological sequelae, following carbon monoxide poisoning. After carbon monoxide exposure, early computed tomography scans and magnetic resonance imaging findings of a 52-year-old woman showed bilateral lesions in the globus pallidus. This patient was discharged and followed for 90 days. The patient recovered without any neurological sequela. In a 58-year-old woman exposed to carbon monoxide, computed tomography showed lesions in bilateral globus pallidus and periventricular white matter. Early magnetic resonance imaging revealed changes similar to that like in early tomography images. The patient recovered and was discharged from hospital. On the 27th day of exposure, the patient developed disorientation and memory impairment. Late magnetic resonance imaging showed diffuse hyperintensity in the cerebral white matter. White matter lesions which progress to demyelination and end up in neuropsychological sequelae cannot always be diagnosed by early computed tomography and magnetic resonance imaging in carbon monoxide poisoning. Copyright © 2014 Sociedade Brasileira de Anestesiologia. Published by Elsevier Editora Ltda. All rights reserved.

Optical cone beam tomography of Cherenkov-mediated signals for fast 3D dosimetry of x-ray photon beams in water.

PubMed

Glaser, Adam K; Andreozzi, Jacqueline M; Zhang, Rongxiao; Pogue, Brian W; Gladstone, David J

2015-07-01

To test the use of a three-dimensional (3D) optical cone beam computed tomography reconstruction algorithm, for estimation of the imparted 3D dose distribution from megavoltage photon beams in a water tank for quality assurance, by imaging the induced Cherenkov-excited fluorescence (CEF). An intensified charge-coupled device coupled to a standard nontelecentric camera lens was used to tomographically acquire two-dimensional (2D) projection images of CEF from a complex multileaf collimator (MLC) shaped 6 MV linear accelerator x-ray photon beam operating at a dose rate of 600 MU/min. The resulting projections were used to reconstruct the 3D CEF light distribution, a potential surrogate of imparted dose, using a Feldkamp-Davis-Kress cone beam back reconstruction algorithm. Finally, the reconstructed light distributions were compared to the expected dose values from one-dimensional diode scans, 2D film measurements, and the 3D distribution generated from the clinical Varian ECLIPSE treatment planning system using a gamma index analysis. A Monte Carlo derived correction was applied to the Cherenkov reconstructions to account for beam hardening artifacts. 3D light volumes were successfully reconstructed over a 400 × 400 × 350 mm(3) volume at a resolution of 1 mm. The Cherenkov reconstructions showed agreement with all comparative methods and were also able to recover both inter- and intra-MLC leaf leakage. Based upon a 3%/3 mm criterion, the experimental Cherenkov light measurements showed an 83%-99% pass fraction depending on the chosen threshold dose. The results from this study demonstrate the use of optical cone beam computed tomography using CEF for the profiling of the imparted dose distribution from large area megavoltage photon beams in water.

Radiation-Induced Liver Injury Mimicking Metastatic Disease in a Patient With Esophageal Cancer: Correlation of Positron Emission Tomography/Computed Tomography With Magnetic Resonance Imaging and Literature Review.

PubMed

Rabe, Tiffany M; Yokoo, Takeshi; Meyer, Jeffrey; Kernstine, Kemp H; Wang, David; Khatri, Gaurav

2016-01-01

Post-radiation therapy evaluation of distal esophageal cancers with positron emission tomography/computed tomography can be problematic. Differentiation of recurrent neoplasm from postradiation changes is difficult in areas of fluorodeoxyglucose avidity in adjacent, incidentally irradiated organs. Few studies have described the magnetic resonance imaging appearance of radiation-induced hepatic injury. We report a case of focal radiation-induced liver injury with a new focus of fluorodeoxyglucose uptake on posttreatment positron emission tomography as well as masslike enhancement and signal abnormality on magnetic resonance imaging, thus mimicking new liver metastasis. Correlation with radiation planning images suggested the correct diagnosis, which was confirmed on follow-up imaging.

A multiresolution approach to iterative reconstruction algorithms in X-ray computed tomography.

PubMed

De Witte, Yoni; Vlassenbroeck, Jelle; Van Hoorebeke, Luc

2010-09-01

In computed tomography, the application of iterative reconstruction methods in practical situations is impeded by their high computational demands. Especially in high resolution X-ray computed tomography, where reconstruction volumes contain a high number of volume elements (several giga voxels), this computational burden prevents their actual breakthrough. Besides the large amount of calculations, iterative algorithms require the entire volume to be kept in memory during reconstruction, which quickly becomes cumbersome for large data sets. To overcome this obstacle, we present a novel multiresolution reconstruction, which greatly reduces the required amount of memory without significantly affecting the reconstructed image quality. It is shown that, combined with an efficient implementation on a graphical processing unit, the multiresolution approach enables the application of iterative algorithms in the reconstruction of large volumes at an acceptable speed using only limited resources.

X-ray Computed Tomography.

ERIC Educational Resources Information Center

Michael, Greg

2001-01-01

Describes computed tomography (CT), a medical imaging technique that produces images of transaxial planes through the human body. A CT image is reconstructed mathematically from a large number of one-dimensional projections of a plane. The technique is used in radiological examinations and radiotherapy treatment planning. (Author/MM)

The Power of Computer-aided Tomography to Investigate Marine Benthic Communities

EPA Science Inventory

Utilization of Computer-aided-Tomography (CT) technology is a powerful tool to investigate benthic communities in aquatic systems. In this presentation, we will attempt to summarize our 15 years of experience in developing specific CT methods and applications to marine benthic co...

Three-dimensional evaluation of human jaw bone microarchitecture: correlation between the microarchitectural parameters of cone beam computed tomography and micro-computer tomography.

PubMed

Kim, Jo-Eun; Yi, Won-Jin; Heo, Min-Suk; Lee, Sam-Sun; Choi, Soon-Chul; Huh, Kyung-Hoe

2015-12-01

To evaluate the potential feasibility of cone beam computed tomography (CBCT) in the assessment of trabecular bone microarchitecture. Sixty-eight specimens from four pairs of human jaw were scanned using both micro-computed tomography (micro-CT) of 19.37-μm voxel size and CBCT of 100-μm voxel size. The correlation of 3-dimensional parameters between CBCT and micro-CT was evaluated. All parameters, except bone-specific surface and trabecular thickness, showed linear correlations between the 2 imaging modalities (P < .05). Among the parameters, bone volume, percent bone volume, trabecular separation, and degree of anisotropy (DA) of CBCT images showed strong correlations with those of micro-CT images. DA showed the strongest correlation (r = 0.693). Most microarchitectural parameters from CBCT were correlated with those from micro-CT. Some microarchitectural parameters, especially DA, could be used as strong predictors of bone quality in the human jaw. Copyright © 2015 Elsevier Inc. All rights reserved.

Evaluation of a continuous-rotation, high-speed scanning protocol for micro-computed tomography.

PubMed

Kerl, Hans Ulrich; Isaza, Cristina T; Boll, Hanne; Schambach, Sebastian J; Nolte, Ingo S; Groden, Christoph; Brockmann, Marc A

2011-01-01

Micro-computed tomography is used frequently in preclinical in vivo research. Limiting factors are radiation dose and long scan times. The purpose of the study was to compare a standard step-and-shoot to a continuous-rotation, high-speed scanning protocol. Micro-computed tomography of a lead grid phantom and a rat femur was performed using a step-and-shoot and a continuous-rotation protocol. Detail discriminability and image quality were assessed by 3 radiologists. The signal-to-noise ratio and the modulation transfer function were calculated, and volumetric analyses of the femur were performed. The radiation dose of the scan protocols was measured using thermoluminescence dosimeters. The 40-second continuous-rotation protocol allowed a detail discriminability comparable to the step-and-shoot protocol at significantly lower radiation doses. No marked differences in volumetric or qualitative analyses were observed. Continuous-rotation micro-computed tomography significantly reduces scanning time and radiation dose without relevantly reducing image quality compared with a normal step-and-shoot protocol.

Management of Liver Cancer Argon-helium Knife Therapy with Functional Computer Tomography Perfusion Imaging.

PubMed

Wang, Hongbo; Shu, Shengjie; Li, Jinping; Jiang, Huijie

2016-02-01

The objective of this study was to observe the change in blood perfusion of liver cancer following argon-helium knife treatment with functional computer tomography perfusion imaging. Twenty-seven patients with primary liver cancer treated with argon-helium knife and were included in this study. Plain computer tomography (CT) and computer tomography perfusion (CTP) imaging were conducted in all patients before and after treatment. Perfusion parameters including blood flows, blood volume, hepatic artery perfusion fraction, hepatic artery perfusion, and hepatic portal venous perfusion were used for evaluating therapeutic effect. All parameters in liver cancer were significantly decreased after argon-helium knife treatment (p < 0.05 to all). Significant decrease in hepatic artery perfusion was also observed in pericancerous liver tissue, but other parameters kept constant. CT perfusion imaging is able to detect decrease in blood perfusion of liver cancer post-argon-helium knife therapy. Therefore, CTP imaging would play an important role for liver cancer management followed argon-helium knife therapy. © The Author(s) 2014.

Characterization of normal feline renal vascular anatomy with dual-phase CT angiography.

PubMed

Cáceres, Ana V; Zwingenberger, Allison L; Aronson, Lillian R; Mai, Wilfried

2008-01-01

Helical computed tomography angiography was used to evaluate the renal vascular anatomy of potential feline renal donors. One hundred and fourteen computed tomography angiograms were reviewed. The vessels were characterized as single without bifurcation, single with bifurcation, double, or triple. Multiplicity was most commonly seen for the right renal vein (45/114 vs. 3/114 multiple left renal veins, 0/114 multiple right renal arteries, and 8/114 multiple left renal arteries). The right kidney was 13.3 times more likely than the left to have multiple renal veins. Additional vascular variants included double caudal vena cava and an accessory renal artery. For the left kidney, surgery and computed tomography angiography findings were in agreement in 92% of 74 cats. For the right kidney, surgery and computed tomography angiography findings were in agreement in 6/6 cats. Our findings of renal vascular anatomy variations in cats were similar to previous reports in humans. Identifying and recognizing the pattern of distribution of these vessels is important when performing renal transplantation.

Stress Computed Tomography Myocardial Perfusion Imaging: A New Topic in Cardiology.

PubMed

Seitun, Sara; Castiglione Morelli, Margherita; Budaj, Irilda; Boccalini, Sara; Galletto Pregliasco, Athena; Valbusa, Alberto; Cademartiri, Filippo; Ferro, Carlo

2016-02-01

Since its introduction about 15 years ago, coronary computed tomography angiography has become today the most accurate clinical instrument for noninvasive assessment of coronary atherosclerosis. Important technical developments have led to a continuous stream of new clinical applications together with a significant reduction in radiation dose exposure. Latest generation computed tomography scanners (≥ 64 slices) allow the possibility of performing static or dynamic perfusion imaging during stress by using coronary vasodilator agents (adenosine, dipyridamole, or regadenoson), combining both functional and anatomical information in the same examination. In this article, the emerging role and state-of-the-art of myocardial computed tomography perfusion imaging are reviewed and are illustrated by clinical cases from our experience with a second-generation dual-source 128-slice scanner (Somatom Definition Flash, Siemens; Erlangen, Germany). Technical aspects, data analysis, diagnostic accuracy, radiation dose and future prospects are reviewed. Copyright © 2015 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

Fatal Road Traffic Vehicle Collisions With Pedestrian Victims: Forensic Postmortem Computed Tomography and Autopsy Correlation.

PubMed

Chatzaraki, Vasiliki; Thali, Michael J; Ampanozi, Garyfalia; Schweitzer, Wolf

2018-06-01

Fatal car-to-pedestrian collisions regularly appear in the forensic pathologist's routine, particularly in places of extended urbanization. Postmortem computed tomography has gained an exceptional role to supplement autopsy worldwide, giving information that is supplementary or complimentary to conventional autopsy. In this retrospective study, a total number of 320 findings in a series of 21 pedestrians fatally hit by cars and trucks of both postmortem computed tomography and autopsy were correlated. According to our results, it is best to combine both methods to give well-founded answers to questions pertaining to both collision reconstruction and cause of death.

[Axial computer tomography of the neurocranium (author's transl)].

PubMed

Stöppler, L

1977-05-27

Computer tomography (CT), a new radiographic examination technique, is very highly efficient, for it has high informative content with little stress for the patient. In contrast to the conventional X-ray technology, CT succeeds, by direct presentation of the structure of the soft parts, in obtaining information which comes close to that of macroscopic neuropathology. The capacity and limitations of the method at the present stage of development are reported. Computer tomography cannot displace conventional neuroradiological methods of investigation, although it is rightly presented as a screening method and helps towards selective use. Indications, technical integration and handling of CT are prerequisites for the exhaustive benefit of the excellent new technique.

Ambient noise adjoint tomography for a linear array in North China

NASA Astrophysics Data System (ADS)

Zhang, C.; Yao, H.; Liu, Q.; Yuan, Y. O.; Zhang, P.; Feng, J.; Fang, L.

2017-12-01

Ambient noise tomography based on dispersion data and ray theory has been widely utilized for imaging crustal structures. In order to improve the inversion accuracy, ambient noise tomography based on the 3D adjoint approach or full waveform inversion has been developed recently, however, the computational cost is tremendous. In this study we present 2D ambient noise adjoint tomography for a linear array in north China with significant computational efficiency compared to 3D ambient noise adjoint tomography. During the preprocessing, we first convert the observed data in 3D media, i.e., surface-wave empirical Green's functions (EGFs) from ambient noise cross-correlation, to the reconstructed EGFs in 2D media using a 3D/2D transformation scheme. Different from the conventional steps of measuring phase dispersion, the 2D adjoint tomography refines 2D shear wave speeds along the profile directly from the reconstructed Rayleigh wave EGFs in the period band 6-35s. With the 2D initial model extracted from the 3D model from traditional ambient noise tomography, adjoint tomography updates the model by minimizing the frequency-dependent Rayleigh wave traveltime misfits between the reconstructed EGFs and synthetic Green function (SGFs) in 2D media generated by the spectral-element method (SEM), with a preconditioned conjugate gradient method. The multitaper traveltime difference measurement is applied in four period bands during the inversion: 20-35s, 15-30s, 10-20s and 6-15s. The recovered model shows more detailed crustal structures with pronounced low velocity anomaly in the mid-lower crust beneath the junction of Taihang Mountains and Yin-Yan Mountains compared with the initial model. This low velocity structure may imply the possible intense crust-mantle interactions, probably associated with the magmatic underplating during the Mesozoic to Cenozoic evolution of the region. To our knowledge, it's first time that ambient noise adjoint tomography is implemented in 2D media. Considering the intensive computational cost and storage of 3D adjoint tomography, this 2D ambient noise adjoint tomography has potential advantages to get high-resolution 2D crustal structures with limited computational resource.

X-Ray Radiography of Gas Turbine Ceramics.

DTIC Science & Technology

1979-10-20

Microfocus X-ray equipment. 1a4ihe definition of equipment concepts for a computer assisted tomography ( CAT ) system; and 4ffthe development of a CAT ...were obtained from these test coupons using Microfocus X-ray and image en- hancement techniques. A Computer Assisted Tomography ( CAT ) design concept...monitor. Computer reconstruction algorithms were investigated with respect to CAT and a preferred approach was determined. An appropriate CAT algorithm

Prospective study of device-related complications in intensive care unit detected by virtual autopsy.

PubMed

Wichmann, D; Heinemann, A; Zähler, S; Vogel, H; Höpker, W; Püschel, K; Kluge, S

2018-06-01

There has been increasing use of invasive techniques, such as extracorporeal organ support, in intensive care units (ICU), and declining autopsy rates. Thus, new measures are needed to maintain high-quality standards. We investigated the potential of computed tomography (CT)-based virtual autopsy to substitute for medical autopsy in this setting. We investigated the potential of virtual autopsy by post-mortem CT to identify complications associated with medical devices in a prospective study of patients who had died in the ICU. Clinical records were reviewed to determine the number and types of medical devices used, and findings from medical and virtual autopsies, related and unrelated to the medical devices, were compared. Medical and virtual autopsies could be performed in 61 patients (Group M/V), and virtual autopsy only in 101 patients (Group V). In Group M/V, 41 device-related complications and 30 device malpositions were identified, but only with a low inter-method agreement. Major findings unrelated to a device were identified in about 25% of patients with a high level of agreement between methods. In Group V, 8 device complications and 36 device malpositions were identified. Device-related complications are frequent in ICU patients. Virtual and medical autopsies showed clear differences in the detection of complications and device malpositions. Both methods should supplement each other rather than one alone for quality control of medical devices in the ICU. Further studies should focus on the identification of special patient populations in which virtual autopsy might be of particular benefit. NCT01541982. Copyright © 2018 British Journal of Anaesthesia. Published by Elsevier Ltd. All rights reserved.

RADIAL COMPUTED TOMOGRAPHY OF AIR CONTAMINANTS USING OPTICAL REMOTE SENSING

EPA Science Inventory

The paper describes the application of an optical remote-sensing (ORS) system to map air contaminants and locate fugitive emissions. Many ORD systems may utilize radial non-overlapping beam geometry and a computed tomography (CT) algorithm to map the concentrations in a plane. In...

Micro computed tomography (CT) scanned anatomical gateway to insect pest bioinformatics

USDA-ARS?s Scientific Manuscript database

An international collaboration to establish an interactive Digital Video Library for a Systems Biology Approach to study the Asian citrus Psyllid and psyllid genomics/proteomics interactions is demonstrated. Advances in micro-CT, digital computed tomography (CT) scan uses X-rays to make detailed pic...

21 CFR 892.1200 - Emission computed tomography system.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Emission computed tomography system. 892.1200 Section 892.1200 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... analysis and display equipment, patient and equipment supports, radionuclide anatomical markers, component...

21 CFR 892.1200 - Emission computed tomography system.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Emission computed tomography system. 892.1200 Section 892.1200 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... analysis and display equipment, patient and equipment supports, radionuclide anatomical markers, component...

21 CFR 892.1200 - Emission computed tomography system.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Emission computed tomography system. 892.1200 Section 892.1200 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... analysis and display equipment, patient and equipment supports, radionuclide anatomical markers, component...

21 CFR 892.1200 - Emission computed tomography system.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Emission computed tomography system. 892.1200 Section 892.1200 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... analysis and display equipment, patient and equipment supports, radionuclide anatomical markers, component...

21 CFR 892.1200 - Emission computed tomography system.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Emission computed tomography system. 892.1200 Section 892.1200 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... analysis and display equipment, patient and equipment supports, radionuclide anatomical markers, component...

PET/CT scanners: a hardware approach to image fusion.

PubMed

Townsend, David W; Beyer, Thomas; Blodgett, Todd M

2003-07-01

New technology that combines positron tomography with x-ray computed tomography (PET/CT) is available from all major vendors of PET imaging equipment: CTI, Siemens, GE, Philips. Although not all vendors have made the same design choices as those described in this review all have in common that their high performance design places a commercial CT scanner in tandem with a commercial PET scanner. The level of physical integration is actually less than that of the original prototype design where the CT and PET components were mounted on the same rotating support. There will undoubtedly be a demand for PET/CT technology with a greater level of integration, and at a reduced cost. This may be achieved through the design of a scanner specifically for combined anatomical and functional imaging, rather than a design combining separate CT and PET scanners, as in the current approaches. By avoiding the duplication of data acquisition and image reconstruction functions, for example, a more integrated design should also allow cost savings over current commercial PET/CT scanners. The goal is then to design and build a device specifically for imaging the function and anatomy of cancer in the most optimal and effective way, without conceptualizing it as combined PET and CT. The development of devices specifically for imaging a particular disease (eg, cancer) differs from the conventional approach of, for example, an all-purpose anatomical imaging device such as a CT scanner. This new concept targets more of a disease management approach rather than the usual division into the medical specialties of radiology (anatomical imaging) and nuclear medicine (functional imaging). Copyright 2003 Elsevier Inc. All rights reserved.

Accuracy and reliability of different cone beam computed tomography (CBCT) devices for structural analysis of alveolar bone in comparison with multislice CT and micro-CT.

PubMed

Van Dessel, Jeroen; Nicolielo, Laura Ferreira Pinheiro; Huang, Yan; Coudyzer, Walter; Salmon, Benjamin; Lambrichts, Ivo; Jacobs, Reinhilde

The aim of this study was to assess whether cone beam computed tomography (CBCT) may be used for clinically reliable alveolar bone quality assessment in comparison to its clinical alternatives, multislice computed tomography and the gold standard (micro-CT). Six dentate mandibular bone samples were scanned with seven CBCT devices (ProMax 3D Max, NewTom GiANO, Cranex 3D, 3D Accuitomo 170, Carestream 9300, Scanora 3D, I-CAT Next generation), one micro-CT scanner (SkyScan 1174) and one MSCT machine (Somatom Definition Flash) using two protocols (standard and high-resolution). MSCT and CBCT images were automatically spatially aligned on the micro-CT scan of the corresponding sample. A volume of interest was manually delineated on the micro-CT image and overlaid on the other scanning devices. Alveolar bone structures were automatically extracted using the adaptive thresholding algorithm. Based on the resulting binary images, an automatic 3D morphometric quantification was performed in a CT-Analyser (Bruker, Kontich, Belgium). The reliability and measurement errors were calculated for each modality compared to the gold standard micro-CT. Both MSCT and CBCT were associated with a clinically and statistically (P <0.05) significant measurement error. Bone quantity-related morphometric indices (bone volume fraction 8.41% min to 17.90% max, bone surface density -0.47 mm-1 min to 0.16 mm-1 max and trabecular thickness 0.15 mm min to 0.31 mm max) were significantly (P <0.05) overestimated, resulting in significantly (P <0.05) closer trabecular pores (total porosity percentage -8.41% min to -17.90% max and fractal dimension 0.08 min to 0.17 max) in all scanners compared to micro-CT. However, the structural pattern of the alveolar bone remained similar compared to that of the micro-CT for the ProMax 3D Max, NewTom GiANO, Cranex 3D, 3D Accuitomo 170 and Carestream 9300. On the other hand, the Scanora 3D, i-CAT Next Generation, standard and high-resolution MSCT displayed an overrated bone quantity and aberrant structural pattern compared to other scanning devices. The calculation of morphometric indices had an overall high reliability (intraclass correlation coefficient [ICC] 0.62 min to 0.99 max), except for the i-CAT Next Generation CBCT (ICC 0.26 min to 0.86 max) and standard resolution MSCT (ICC 0.10 min to 0.62 max). This study demonstrated that most CBCT machines may be able to quantitatively assess alveolar bone quality, with a level of accuracy and reliability that approaches micro-CT. One may therefore propose to extrapolate this to clinical CBCT imaging, certainly when there is a need for implant rehabilitation in dentate jaw bones. Conflict-of-interest statement: There is no conflict of interest to declare. Fellowship support was received from Research Foundation Flanders (FWO) from the Belgian government and from the Coordination for the Improvement of Higher Education Personnel (CAPES) programme, Science without Borders, from the Brazilian government.

A computer-aided system for automatic extraction of femur neck trabecular bone architecture using isotropic volume construction from clinical hip computed tomography images.

PubMed

Vivekanandhan, Sapthagirivasan; Subramaniam, Janarthanam; Mariamichael, Anburajan

2016-10-01

Hip fractures due to osteoporosis are increasing progressively across the globe. It is also difficult for those fractured patients to undergo dual-energy X-ray absorptiometry scans due to its complicated protocol and its associated cost. The utilisation of computed tomography for the fracture treatment has become common in the clinical practice. It would be helpful for orthopaedic clinicians, if they could get some additional information related to bone strength for better treatment planning. The aim of our study was to develop an automated system to segment the femoral neck region, extract the cortical and trabecular bone parameters, and assess the bone strength using an isotropic volume construction from clinical computed tomography images. The right hip computed tomography and right femur dual-energy X-ray absorptiometry measurements were taken from 50 south-Indian females aged 30-80 years. Each computed tomography image volume was re-constructed to form isotropic volumes. An automated system by incorporating active contour models was used to segment the neck region. A minimum distance boundary method was applied to isolate the cortical and trabecular bone components. The trabecular bone was enhanced and segmented using trabecular enrichment approach. The cortical and trabecular bone features were extracted and statistically compared with dual-energy X-ray absorptiometry measured femur neck bone mineral density. The extracted bone measures demonstrated a significant correlation with neck bone mineral density (r > 0.7, p < 0.001). The inclusion of cortical measures, along with the trabecular measures extracted after isotropic volume construction and trabecular enrichment approach procedures, resulted in better estimation of bone strength. The findings suggest that the proposed system using the clinical computed tomography images scanned with low dose could eventually be helpful in osteoporosis diagnosis and its treatment planning. © IMechE 2016.

En Face Optical Coherence Tomography Angiography Imaging Versus Fundus Photography in the Measurement of Choroidal Nevi.

PubMed

Lee, Michele D; Kaidonis, Georgia; Kim, Alice Y; Shields, Ryan A; Leng, Theodore

2017-09-01

Choroidal nevi are common benign intraocular tumors with a small risk of malignant transformation. This retrospective study investigates the use of en face spectral-domain optical coherence tomography angiography (SD-OCTA) in determining the clinical features and measurement of choroidal nevi. Patients with choroidal nevi were imaged with both OCTA and a fundus photography device. Greatest longitudinal dimension (GLD), perpendicular dimension (PD), and the GLD/PD ratio were assessed on each device. Inter-device variation and intra- and inter-rater reliability analyses were performed. Fourteen patients with choroidal nevi were included. No significant difference between the GLD/PD ratio as measured by all three devices was found (Chi-square = 2.8, 2 df, P = .247). Intraclass correlation coefficients were greater than 0.7 for repeated measures on all devices, suggesting good repeatability and reproducibility. This study demonstrated inter-device consistency and high intra- and inter-rater reliability when measuring choroidal nevi. [Ophthalmic Surg Lasers Imaging Retina. 2017;48:741-747.]. Copyright 2017, SLACK Incorporated.

Positron emission tomography/computed tomography in melanoma.

PubMed

Bourgeois, Austin C; Chang, Ted T; Fish, Lindsay M; Bradley, Yong C

2013-09-01

Fludeoxyglucose F 18 positron emission tomography/computed tomography (PET/CT) has been invaluable in the assessment of melanoma throughout the course of the disease. As with any modality, the studies are incomplete and more information will be gleaned as our experience progresses. Additionally, it is hoped that a newer PET agent in the pipeline will give us even greater success in the identification and subsequent treatment of melanoma. This article aims to examine the utilization of PET/CT in the staging, prognostication, and follow-up of melanoma while providing the physicians who order and interpret these studies practical guidelines and interpretive pitfalls. Copyright © 2013 Elsevier Inc. All rights reserved.

Miscellaneous indications in bone scintigraphy: metabolic bone diseases and malignant bone tumors.

PubMed

Cook, Gary J R; Gnanasegaran, Gopinath; Chua, Sue

2010-01-01

The diphosphonate bone scan is ideally suited to assess many global, focal or multifocal metabolic bone disorders and there remains a role for conventional bone scintigraphy in metabolic bone disorders at diagnosis, investigation of complications, and treatment response assessment. In contrast, the role of bone scintigraphy in the evaluation of primary malignant bone tumors has reduced with the improvement of morphologic imaging, such as computed tomography and magnetic resonance imaging. However, an increasing role for (18)F-fluorodeoxyglucose positron emission tomography and positron emission tomography/computed tomography is emerging as a functional assessment at diagnosis, staging, and neoadjuvant treatment response assessment.

Usefulness of fluorodeoxyglucose positron emission tomography/computed tomography for detection of a neuroblastic nodule in a ganglioneuroblastoma: a case report.

PubMed

Takeda, Yuka; Sano, Hideki; Kawano, Asuka; Mochizuki, Kazuhiro; Takahashi, Nobuhisa; Kobayashi, Shogo; Ohara, Yoshihiro; Tasaki, Kazuhiro; Hosoya, Mitusuaki; Kikuta, Atsushi

2018-05-03

Ganglioneuroblastoma, nodular is defined as a composite tumor of biologically distinct clones. The peripheral neuroblastic tumors in this category are characterized by the presence of grossly visible neuroblastoma nodules coexisting with ganglioneuroblastoma, intermixed, or with ganglioneuroma. Making a correct diagnosis of ganglioneuroblastoma, nodular is often difficult by biopsy or partial tumor resection, because the neuroblastic nodule could be hidden and not sampled for pathological examination. We report a case of a Japanese boy aged 3 years, 8 months, with an unresectable abdominal tumor and elevated vanillylmandelic acid and homovanillic acid levels. The initial biopsy was ganglioneuroma. However, after the second biopsy from a hidden neuroblastoma nodule that was clearly highlighted by fluorodeoxyglucose positron emission tomography/computed tomography, we reached the diagnosis of ganglioneuroblastoma, nodular. Because the nodule demonstrated neuroblastoma, differentiating subtype, with a low mitosis-karyorrhexis index (favorable histology) and nonamplified MYCN, the boy was treated according to the intermediate-risk protocol and is now alive and well 4 years after the diagnosis. This case illustrates the critical role of fluorodeoxyglucose positron emission tomography/computed tomography for detecting a neuroblastoma nodule in a ganglioneuroblastoma.

FDG-PET/CT in the evaluation of anal carcinoma

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

Cotter, Shane E.; Medical Scientist Training Program, Washington University School of Medicine, St. Louis, MO; Grigsby, Perry W.

2006-07-01

Purpose: Surgical staging and treatment of anal carcinoma has been replaced by noninvasive staging studies and combined modality therapy. In this study, we compare computed tomography (CT) and physical examination to [{sup 18}F]-fluoro-2-deoxy-D-glucose-positron emission tomography/computed tomography (FDG-PET/CT) in the staging of carcinoma of the anal canal, with special emphasis on determination of spread to inguinal lymph nodes. Methods and Materials: Between July 2003 and July 2005, 41 consecutive patients with biopsy-proved anal carcinoma underwent a complete staging evaluation including physical examination, CT, and 2-FDG-PET/CT. Patients ranged in age from 30 to 89 years. Nine men were HIV-positive. Treatment was withmore » standard Nigro regimen. Results: [{sup 18}F]-fluoro-2-deoxy-D-glucose-positron emission tomography/computed tomography (FDG-PET/CT) detected 91% of nonexcised primary tumors, whereas CT visualized 59%. FDG-PET/CT detected abnormal uptake in pelvic nodes of 5 patients with normal pelvic CT scans. FDG-PET/CT detected abnormal nodes in 20% of groins that were normal by CT, and in 23% without abnormality on physical examination. Furthermore, 17% of groins negative by both CT and physical examination showed abnormal uptake on FDG-PET/CT. HIV-positive patients had an increased frequency of PET-positive lymph nodes. Conclusion: [{sup 18}F]-fluoro-2-deoxy-D-glucose-positron emission tomography/computed tomography detects the primary tumor more often than CT. FDG-PET/CT detects substantially more abnormal inguinal lymph nodes than are identified by standard clinical staging with CT and physical examination.« less

Insights from the conduct of a device trial in older persons: Low Magnitude Mechanical Stimulation for Musculoskeletal Health

PubMed Central

Kiel, Douglas P.; Hannan, Marian T.; Barton, Bruce A.; Bouxsein, Mary L.; Lang, Thomas. F.; Brown, Kathleen M.; Shane, Elizabeth; Magaziner, Jay; Zimmerman, Sheryl; Rubin, Clinton T.

2011-01-01

Background Osteoporosis is a common complication of aging. Alternatives to pharmacologic treatment are needed for older adults. Non-pharmacologic treatment with low magnitude, high frequency mechanical stimulation has been shown to prevent bone loss in animal and human studies. Methods The VIBES (Vibration to Improve Bone Density in Elderly Subjects) study is a randomized, double-blind, sham-controlled trial of the efficacy of low magnitude, high frequency mechanical stimulation in 200 men and women aged 60 years and older with bone mineral density T-scores by dual-x-ray absorptiometry between –1 and –2.5 at entry. Participants are healthy, cognitively intact residents of independent living communities in the Boston area who receive free calcium and Vitamin D supplements. They are randomly assigned to active or sham treatment and stand on their assigned platform once daily for 10 minutes. All platforms have adherence data collection software downloadable to a laptop computer. Adverse events are closely monitored. 174 participants were randomized and will be followed for two years. Almost all active subjects have attained one year of follow-up. Bone mineral density is measured by both dual x-ray absorptiometry and quantitative computed tomography at baseline and annually. The main analysis will compare mean changes from baseline in volumetric bone density by quantitative computed tomography in active and sham groups. Adherence and treatment effect magnitude will also be evaluated. Secondary analyses will compare changes in three biochemical markers of bone turnover as well as longitudinal comparisons of muscle and balance endpoints. Results The VIBES trial has completed its first year of data collection and encountered multiple challenges leading to valuable lessons learned about the areas of recruitment from independent living communities, deployment of multi-user mechanical devices using radio frequency identification cards and electronic adherence monitoring, organization of transportation for imaging at a central site, and the expansion of study aims to include additional musculoskeletal outcomes. Conclusions These lessons will guide future investigations in studies of individuals of advanced age. PMID:20571129

Tricuspid regurgitation in patients with pacemakers and implantable cardiac defibrillators: a comprehensive review.

PubMed

Al-Bawardy, Rasha; Krishnaswamy, Amar; Bhargava, Mandeep; Dunn, Justin; Wazni, Oussama; Tuzcu, E Murat; Stewart, William; Kapadia, Samir R

2013-05-01

Implantable cardiac devices, including defibrillators and pacemakers, may be the cause of tricuspid regurgitation (TR) or may worsen existing TR. This review of the literature suggests that TR usually occurs over time after lead implantation. Diagnosis by clinical exam and 2-dimensional echocardiography may be augmented by 3-dimensional echocardiography and/or computed tomography. The mechanism may be mechanical perforation or laceration of leaflets, scarring and restriction of leaflets, or asynchronized activation of the right ventricle. Pacemaker-related TR might cause severe right-sided heart failure, but data regarding associated mortality are lacking. This comprehensive review summarizes the data regarding incidence, mechanism, and treatment of lead-related TR. © 2013 Wiley Periodicals, Inc.

Additive manufacturing of titanium alloys in the biomedical field: processes, properties and applications.

PubMed

Trevisan, Francesco; Calignano, Flaviana; Aversa, Alberta; Marchese, Giulio; Lombardi, Mariangela; Biamino, Sara; Ugues, Daniele; Manfredi, Diego

2018-04-01

The mechanical properties and biocompatibility of titanium alloy medical devices and implants produced by additive manufacturing (AM) technologies - in particular, selective laser melting (SLM), electron beam melting (EBM) and laser metal deposition (LMD) - have been investigated by several researchers demonstrating how these innovative processes are able to fulfil medical requirements for clinical applications. This work reviews the advantages given by these technologies, which include the possibility to create porous complex structures to improve osseointegration and mechanical properties (best match with the modulus of elasticity of local bone), to lower processing costs, to produce custom-made implants according to the data for the patient acquired via computed tomography and to reduce waste.

A Simple Approach to the Technical Aspects of Radiosurgery Treatments

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

Prasad, S.C.; Bassano, D.A.; King, G.A.

2015-01-15

An approach to radiosurgery treatment that can be readily adopted in most radiotherapy centers with linear accelerators is presented. In our institution, a Leksell-type of neurosurgical frame, a computed tomography scanner, locally fabricated cones, and 6 MV X-ray beams are used to perform radiosurgery treatments. Collimated arcs with dose distributions that conform to the shape of the lesion in the transverse and the sagittal planes are used. It is argued that the uncertainties in the localization of the isocenter within a lesion and the specifications of the size of the target volume do not justify high precision mechanical devices formore » most radiosurgery treatments.« less

High resolution X-ray CT for advanced electronics packaging

NASA Astrophysics Data System (ADS)

Oppermann, M.; Zerna, T.

2017-02-01

Advanced electronics packaging is a challenge for non-destructive Testing (NDT). More, smaller and mostly hidden interconnects dominate modern electronics components and systems. To solve the demands of customers to get products with a high functionality by low volume, weight and price (e.g. mobile phones, personal medical monitoring systems) often the designers use System-in-Package solutions (SiP). The non-destructive testing of such devices is a big challenge. So our paper will impart fundamentals and applications for non-destructive evaluation of inner structures of electronics packaging for quality assurance and reliability investigations with a focus on X-ray methods, especially on high resolution X-ray computed tomography (CT).

The usefulness of three-dimensional imaging in the diagnosis and treatment of clinically ambiguous gingival swelling.

PubMed

Kabashima, Hiroaki; Mizobe, Kunitaka; Nakamuta, Hiroyoshi; Fujiwara, Hiroaki; Okamura, Kazutoshi; Unemori, Masako; Akamine, Akifumi; Yoshiura, Kazunori; Maeda, Katsumasa

2011-06-01

We evaluated and treated a 54-year-old woman with gingival swelling. Conventional intraoral and panoramic radiography did not provide sufficient information for either determining the cause of gingival swelling or planning treatment of clinical symptoms. The 3D Accuitomo XYZ Slice View Tomograph (3DX) is a compact dental computed tomography device that allowed for accurate identification and optimal treatment of the causes of gingival swelling. At four years after treatment, 3DX radiographs showed no abnormalities in treated teeth or healing of surrounding structures. We conclude that high-resolution 3D images obtained with 3DX promise to be very effective for diagnosing oral diseases and determining effective treatment.

Ovarian tissue cryopreservation by stepped vitrification and monitored by X-ray computed tomography.

PubMed

Corral, Ariadna; Clavero, Macarena; Gallardo, Miguel; Balcerzyk, Marcin; Amorim, Christiani A; Parrado-Gallego, Ángel; Dolmans, Marie-Madeleine; Paulini, Fernanda; Morris, John; Risco, Ramón

2018-04-01

Ovarian tissue cryopreservation is, in most cases, the only fertility preservation option available for female patients soon to undergo gonadotoxic treatment. To date, cryopreservation of ovarian tissue has been carried out by both traditional slow freezing method and vitrification, but even with the best techniques, there is still a considerable loss of follicle viability. In this report, we investigated a stepped cryopreservation procedure which combines features of slow cooling and vitrification (hereafter called stepped vitrification). Bovine ovarian tissue was used as a tissue model. Stepwise increments of the Me 2 SO concentration coupled with stepwise drops-in temperature in a device specifically designed for this purpose and X-ray computed tomography were combined to investigate loading times at each step, by monitoring the attenuation of the radiation proportional to Me 2 SO permeation. Viability analysis was performed in warmed tissues by immunohistochemistry. Although further viability tests should be conducted after transplantation, preliminary results are very promising. Four protocols were explored. Two of them showed a poor permeation of the vitrification solution (P1 and P2). The other two (P3 and P4), with higher permeation, were studied in deeper detail. Out of these two protocols, P4, with a longer permeation time at -40 °C, showed the same histological integrity after warming as fresh controls. Copyright © 2018 Elsevier Inc. All rights reserved.

Four-dimensional computed tomography based respiratory-gated radiotherapy with respiratory guidance system: analysis of respiratory signals and dosimetric comparison.

PubMed

Lee, Jung Ae; Kim, Chul Yong; Yang, Dae Sik; Yoon, Won Sup; Park, Young Je; Lee, Suk; Kim, Young Bum

2014-01-01

To investigate the effectiveness of respiratory guidance system in 4-dimensional computed tomography (4 DCT) based respiratory-gated radiation therapy (RGRT) by comparing respiratory signals and dosimetric analysis of treatment plans. The respiratory amplitude and period of the free, the audio device-guided, and the complex system-guided breathing were evaluated in eleven patients with lung or liver cancers. The dosimetric parameters were assessed by comparing free breathing CT plan and 4 DCT-based 30-70% maximal intensity projection (MIP) plan. The use of complex system-guided breathing showed significantly less variation in respiratory amplitude and period compared to the free or audio-guided breathing regarding the root mean square errors (RMSE) of full inspiration (P = 0.031), full expiration (P = 0.007), and period (P = 0.007). The dosimetric parameters including V(5 Gy), V(10 Gy), V(20 Gy), V(30 Gy), V(40 Gy), and V(50 Gy) of normal liver or lung in 4 DCT MIP plan were superior over free breathing CT plan. The reproducibility and regularity of respiratory amplitude and period were significantly improved with the complex system-guided breathing compared to the free or the audio-guided breathing. In addition, the treatment plan based on the 4D CT-based MIP images acquired with the complex system guided breathing showed better normal tissue sparing than that on the free breathing CT.

Comparison of conventional and cadmium-zinc-telluride single-photon emission computed tomography for analysis of thallium-201 myocardial perfusion imaging: an exploratory study in normal databases for different ethnicities.

PubMed

Ishihara, Masaru; Onoguchi, Masahisa; Taniguchi, Yasuyo; Shibutani, Takayuki

2017-12-01

The aim of this study was to clarify the differences in thallium-201-chloride (thallium-201) myocardial perfusion imaging (MPI) scans evaluated by conventional anger-type single-photon emission computed tomography (conventional SPECT) versus cadmium-zinc-telluride SPECT (CZT SPECT) imaging in normal databases for different ethnic groups. MPI scans from 81 consecutive Japanese patients were examined using conventional SPECT and CZT SPECT and analyzed with the pre-installed quantitative perfusion SPECT (QPS) software. We compared the summed stress score (SSS), summed rest score (SRS), and summed difference score (SDS) for the two SPECT devices. For a normal MPI reference, we usually use Japanese databases for MPI created by the Japanese Society of Nuclear Medicine, which can be used with conventional SPECT but not with CZT SPECT. In this study, we used new Japanese normal databases constructed in our institution to compare conventional and CZT SPECT. Compared with conventional SPECT, CZT SPECT showed lower SSS (p < 0.001), SRS (p = 0.001), and SDS (p = 0.189) using the pre-installed SPECT database. In contrast, CZT SPECT showed no significant difference from conventional SPECT in QPS analysis using the normal databases from our institution. Myocardial perfusion analyses by CZT SPECT should be evaluated using normal databases based on the ethnic group being evaluated.

Experimental and Numerical Evaluation of the Mechanical Behavior of Strongly Anisotropic Light-Weight Metallic Fiber Structures under Static and Dynamic Compressive Loading

PubMed Central

Andersen, Olaf; Vesenjak, Matej; Fiedler, Thomas; Jehring, Ulrike; Krstulović-Opara, Lovre

2016-01-01

Rigid metallic fiber structures made from a variety of different metals and alloys have been investigated mainly with regard to their functional properties such as heat transfer, pressure drop, or filtration characteristics. With the recent advent of aluminum and magnesium-based fiber structures, the application of such structures in light-weight crash absorbers has become conceivable. The present paper therefore elucidates the mechanical behavior of rigid sintered fiber structures under quasi-static and dynamic loading. Special attention is paid to the strongly anisotropic properties observed for different directions of loading in relation to the main fiber orientation. Basically, the structures show an orthotropic behavior; however, a finite thickness of the fiber slabs results in moderate deviations from a purely orthotropic behavior. The morphology of the tested specimens is examined by computed tomography, and experimental results for different directions of loading as well as different relative densities are presented. Numerical calculations were carried out using real structural data derived from the computed tomography data. Depending on the direction of loading, the fiber structures show a distinctively different deformation behavior both experimentally and numerically. Based on these results, the prevalent modes of deformation are discussed and a first comparison with an established polymer foam and an assessment of the applicability of aluminum fiber structures in crash protection devices is attempted. PMID:28773522

FPGA Based High Speed Data Acquisition System for Electrical Impedance Tomography

PubMed Central

Khan, S; Borsic, A; Manwaring, Preston; Hartov, Alexander; Halter, Ryan

2014-01-01

Electrical Impedance Tomography (EIT) systems are used to image tissue bio-impedance. EIT provides a number of features making it attractive for use as a medical imaging device including the ability to image fast physiological processes (>60 Hz), to meet a range of clinical imaging needs through varying electrode geometries and configurations, to impart only non-ionizing radiation to a patient, and to map the significant electrical property contrasts present between numerous benign and pathological tissues. To leverage these potential advantages for medical imaging, we developed a modular 32 channel data acquisition (DAQ) system using National Instruments’ PXI chassis, along with FPGA, ADC, Signal Generator and Timing and Synchronization modules. To achieve high frame rates, signal demodulation and spectral characteristics of higher order harmonics were computed using dedicated FFT-hardware built into the FPGA module. By offloading the computing onto FPGA, we were able to achieve a reduction in throughput required between the FPGA and PC by a factor of 32:1. A custom designed analog front end (AFE) was used to interface electrodes with our system. Our system is wideband, and capable of acquiring data for input signal frequencies ranging from 100 Hz to 12 MHz. The modular design of both the hardware and software will allow this system to be flexibly configured for the particular clinical application. PMID:24729790

Experimental and Numerical Evaluation of the Mechanical Behavior of Strongly Anisotropic Light-Weight Metallic Fiber Structures under Static and Dynamic Compressive Loading.

PubMed

Andersen, Olaf; Vesenjak, Matej; Fiedler, Thomas; Jehring, Ulrike; Krstulović-Opara, Lovre

2016-05-21

Rigid metallic fiber structures made from a variety of different metals and alloys have been investigated mainly with regard to their functional properties such as heat transfer, pressure drop, or filtration characteristics. With the recent advent of aluminum and magnesium-based fiber structures, the application of such structures in light-weight crash absorbers has become conceivable. The present paper therefore elucidates the mechanical behavior of rigid sintered fiber structures under quasi-static and dynamic loading. Special attention is paid to the strongly anisotropic properties observed for different directions of loading in relation to the main fiber orientation. Basically, the structures show an orthotropic behavior; however, a finite thickness of the fiber slabs results in moderate deviations from a purely orthotropic behavior. The morphology of the tested specimens is examined by computed tomography, and experimental results for different directions of loading as well as different relative densities are presented. Numerical calculations were carried out using real structural data derived from the computed tomography data. Depending on the direction of loading, the fiber structures show a distinctively different deformation behavior both experimentally and numerically. Based on these results, the prevalent modes of deformation are discussed and a first comparison with an established polymer foam and an assessment of the applicability of aluminum fiber structures in crash protection devices is attempted.

Development of a phantom and a methodology for evaluation of depth kerma and kerma index for dental cone beam computed tomography.

PubMed

Batista, W O; Navarro, M V T; Maia, A F

2013-12-01

Basically, all modalities of diagnostic radiology require phantoms suitable for dosimetric evaluations. New technologies frequently arise unaccompanied of tools for dosimetric evaluations and quality control. In this study, a low-cost phantom and a consequent proposed methodology for dosimetric evaluations in cone beam computed tomography (CBCT) were presented. The developed phantom has typical dimensions of the human face, was built in polymethyl methacrylate and filled with water. Three devices with different technological concepts were evaluated and a proposed index, kerma index-height product (PKIH), was defined as an option to the use of air kerma-area product. The results of this study show relatively uniform kerma profiles for scanners with field of views (FOVs) of large diameters and non-uniform for FOVs of small diameters. With regard to the values obtained for the kerma indexes, much higher values were found for the equipment FOVs with small diameter compared with the values of the two other equipment that have larger diameters. The results indicate that (1) there is a need for special phantoms for use in CBCT, (2) the use of P(KA) in the evaluation of protocols on different equipment can lead to false interpretations and (3) the new index is a suitable alternative for the use of P(KA) in CBCT.

Evaluation of mini-implant sites in the posterior maxilla using traditional radiographs and cone-beam computed tomography

PubMed Central

Abbassy, Mona A.; Sabban, Hanady M.; Hassan, Ali H.; Zawawi, Khalid H.

2015-01-01

Objectives: To evaluate the accuracy of using routine 2-dimensional (2D) radiographs (panoramic and periapical) when evaluating the position of orthodontic temporary anchorage devices (mini-implants) in the maxilla, and to compare the results to 3-dimensional cone-beam computed tomography (CBCT). Methods: This cross-sectional study was conducted at King Abdulaziz University, Faculty of Dentistry, Jeddah, Kingdom of Saudi Arabia from February 2014 to January 2015. Panoramic and periapical radiographs were used to examine the position of mini-implants in relation to the adjacent roots. Rating of mini-implants position was performed by 82 dentists from different specialties, using 2 D images according to the following criteria: 1) away from the root; 2) mini-implant tip appears touching the lamina dura; and 3) mini-implant overlays the lamina dura. The results were compared with CBCT findings. Results: There was no difference between dentists from different specialties when rating the position of the mini-implants (Cronbach’s alpha=0.956). The accuracy of the periapical images was 45.1%, while the panoramic images 33.6%. However, both panoramic and periapical radiographs were significantly inaccurate when assessing the mini-implant position when compared with the CBCT findings (p=0.0001). Conclusion: Three-dimensional CBCT technology allows better visualization of mini-implant placement. The use of CBCT when assessing the position of mini-implants is recommended. PMID:26593168

Sensitivity and specificity of cone beam computed tomography in thin bony structures in maxillofacial surgery – A clinical trial.

PubMed

Thönissen, P; Ermer, M A; Schmelzeisen, R; Gutwald, R; Metzger, M C; Bittermann, G

2015-09-01

Cone-Beam Computed Tomography (CBCT) has become widely used in dentistry and maxillofacial surgery. Accuracy, sensitivity and specificity of thin bony structures below 0.5 mm have been subject of some in vitro studies. This prospective in vivo study investigates the correlation between preoperative CBCT-imaging and intraoperative clinical examination of thin bony structures. We hereby present results from daily clinical routine. A total number of 80 sites in 64 patients has been examined to differentiate between preoperative 3D imaging and clinical measurements on cystic lesions in maxilla and mandible. Different CBCT-devices with a voxel size ranging from 0.08 mm to 0.4 mm were used. Overall-specificity found for detecting thin bony structures of the human jaw is 13.89%, overall sensitivity is 100%, positive predictive value (PPV) is 58.67% and negative predictive value (NPV) is 100%. Image quality is the key to make use of additional information CBCT provides and depends on spatial, temporal and contrast resolution. CBCT does not depict reliably thin bony structures of the jaw, even if high voxel resolution is used. In selected cases using high resolution protocols should be considered despite affecting the patient with higher doses of radiation. Copyright © 2015 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Analysis of the mechanical behavior of a titanium scaffold with a repeating unit-cell substructure.

PubMed

Ryan, Garrett; McGarry, Patrick; Pandit, Abhay; Apatsidis, Dimitrios

2009-08-01

Titanium scaffolds with controlled microarchitecture have been developed for load bearing orthopedic applications. The controlled microarchitecture refers to a repeating array of unit-cells, composed of sintered titanium powder, which make up the scaffold structure. The objective of this current research was to characterize the mechanical performance of three scaffolds with increasing porosity, using finite element analysis (FEA) and to compare the results with experimental data. Scaffolds were scanned using microcomputed tomography and FEA models were generated from the resulting computer models. Macroscale and unit-cell models of the scaffolds were created. The material properties of the sintered titanium powders were first evaluated in mechanical tests and the data used in the FEA. The macroscale and unit-cell FEA models proved to be a good predictor of Young's modulus and yield strength. Although macroscale models showed similar failure patterns and an expected trend in UCS, strain at UCS did not compare well with experimental data. Since a rapid prototyping method was used to create the scaffolds, the original CAD geometries of the scaffold were also evaluated using FEA but they did not reflect the mechanical properties of the physical scaffolds. This indicates that at present, determining the actual geometry of the scaffold through computed tomography imaging is important. Finally, a fatigue analysis was performed on the scaffold to simulate the loading conditions it would experience as a spinal interbody fusion device.

Analysis of plastic deformation in cortical bone after insertion of coated and non-coated self-tapping orthopaedic screws.

PubMed

Koistinen, A P; Korhonen, H; Kiviranta, I; Kröger, H; Lappalainen, R

2011-07-01

Insertion of internal fracture fixation devices, such as screws, mechanically weakens the bone. Diamond-like carbon has outstanding tribology properties which may decrease the amount of damage in tissue. The purpose of this study was to investigate methods for quantification of cortical bone damage after orthopaedic bone screw insertion and to evaluate the effect of surface modification on tissue damage. In total, 48 stainless steel screws were inserted into cadaver bones. Half of the screws were coated with a smooth amorphous diamond coating. Geometrical data of the bones was determined by peripheral quantitative computed tomography. Thin sections of the bone samples were prepared after screw insertion, and histomorphometric evaluation of damage was performed on images obtained using light microscopy. Micro-computed tomography and scanning electron microscopy were also used to examine tissue damage. A positive correlation was found between tissue damage and the geometric properties of the bone. The age of the cadaver significantly affected the bone mineral density, as well as the damage perimeter and diameter of the screw hole. However, the expected positive effect of surface modification was probably obscured by large variations in the results and, thus, statistically significant differences were not found in this study. This can be explained by natural variability in bone tissue, which also made automated image analysis difficult.

Abdominal perforation after rupture of a diamond-studded wire: a case report.

PubMed

Schmelzle, Moritz; Matthaei, Hanno; Tustas, Roy Y; Schmitt, Marcus; Müller-Mattheis, Volker; Linhart, Wolfgang; Eisenberger, Claus F; Knoefel, Wolfram T; Esch, Jan Schulte Am

2008-11-13

There are numerous cases of abdominal injuries due to bullets. Abdominal injuries due to bullets are a diagnostic and therapeutic challenge. Here, an unusual case of an abdominal perforation caused by a metal projectile, lead to confusion in the interpretation of the preoperative computer tomography. We present an unusual case of a 32-year-old male worker who sustained a "shot" to the left upper abdominal quadrant, as a result of a work-related accident. The projectile derived from a special wire that tore during operation. One chain element happened to accelerate towards the patients belly and perforated the abdominal wall. Computer tomography located the radiopaque projectile to the cortex of the left kidney and showed a lesion of the tail of the pancreas. The presence of intraperitoneal free air suggested a gastrointestinal perforation. Immediate open exploration of the peritoneal cavity and the retroperitoneal space revealed perforating lesions of the anterior and posterior gastric wall, as well as the pancreatic tail. The projectile was finally retrieved in the upper pole of the left kidney. The patient had a good clinical course subsequent to surgery and was discharged in good general condition. This case represents a rare form of a retained bullet injury and corroborates the need of sufficient measures of worker-protection in area of diamond-studded wire cutting devices.

Segmenting root systems in xray computed tomography images using level sets

USDA-ARS?s Scientific Manuscript database

The segmentation of plant roots from soil and other growing mediums in xray computed tomography images is needed to effectively study the shapes of roots without excavation. However, segmentation is a challenging problem in this context because the root and non-root regions share similar features. ...

Retroperitoneal tumour radiotherapy: clinical improvements using kilovoltage cone beam computed tomography.

PubMed

Juan-Senabre, Xavier J; Ferrer-Albiach, Carlos; Rodríguez-Cordón, Marta; Santos-Serra, Agustín; López-Tarjuelo, Juan; Calzada-Feliu, Salvador

2009-04-01

We present a clinical case of a patient diagnosed with a retroperitoneal sarcoma, which received preoperative treatment with daily verification via computed tomography obtained with kilovoltage cone beam. We compare the benefit of this treatment compared to other conventional treatment without image guiding, reporting quantitative results.

Imaging Techniques in Endodontics: An Overview

PubMed Central

Deepak, B. S.; Subash, T. S.; Narmatha, V. J.; Anamika, T.; Snehil, T. K.; Nandini, D. B.

2012-01-01

This review provides an overview of the relevance of imaging techniques such as, computed tomography, cone beam computed tomography, and ultrasound, to endodontic practice. Many limitations of the conventional radiographic techniques have been overcome by the newer methods. Advantages and disadvantages of various imaging techniques in endodontic practice are also discussed. PMID:22530184

SIMULATION STUDY FOR GASEOUS FLUXES FROM AN AREA SOURCE USING COMPUTED TOMOGRAPHY AND OPTICAL REMOTE SENSING

EPA Science Inventory

The paper presents a new approach to quantifying emissions from fugitive gaseous air pollution sources. Computed tomography (CT) and path-integrated optical remote sensing (PI-ORS) concentration data are combined in a new field beam geometry. Path-integrated concentrations are ...

Computed tomography as a diagnostic aid for extracanal invasive resorption.

PubMed

Kim, Euiseong; Kim, Kee-Deog; Roh, Byoung-Duck; Cho, Yong-Sik; Lee, Seung-Jong

2003-07-01

A case of multiple extracanal invasive resorption is reported. The patient had a history of hypothyroidism for approximately 1 yr before the dental visit. Utilization of computed tomography and a rapid prototyping tooth model in diagnosing the exact location and the size of the resorption area are discussed.

Single photon emission computed tomography in motor neuron disease with dementia.

PubMed

Sawada, H; Udaka, F; Kishi, Y; Seriu, N; Mezaki, T; Kameyama, M; Honda, M; Tomonobu, M

1988-01-01

Single photon emission computed tomography with [123 I] isopropylamphetamine was carried out on a patient with motor neuron disease with dementia. [123 I] uptake was decreased in the frontal lobes. This would reflect the histopathological findings such as neuronal loss and gliosis in the frontal lobes.

APPLICATION OF 3D COMPUTER-AIDED TOMOGRAPHY TO THE QUANTIFICATION OF MARINE SEDIMENT COMMUNITIES IN POLLUTION GRADIENTS

EPA Science Inventory

Computer-Aided Tomography (CT) has been demonstrated to be a cost efficient tool for the qualitative and quantitative study of estuarine benthic communities along pollution gradients.
Now we have advanced this technology to successfully visualize and discriminate three dimen...

Spatial image modulation to improve performance of computed tomography imaging spectrometer

NASA Technical Reports Server (NTRS)

Bearman, Gregory H. (Inventor); Wilson, Daniel W. (Inventor); Johnson, William R. (Inventor)

2010-01-01

Computed tomography imaging spectrometers ("CTIS"s) having patterns for imposing spatial structure are provided. The pattern may be imposed either directly on the object scene being imaged or at the field stop aperture. The use of the pattern improves the accuracy of the captured spatial and spectral information.

Advanced imaging in COPD: insights into pulmonary pathophysiology

PubMed Central

Milne, Stephen

2014-01-01

Chronic obstructive pulmonary disease (COPD) involves a complex interaction of structural and functional abnormalities. The two have long been studied in isolation. However, advanced imaging techniques allow us to simultaneously assess pathological processes and their physiological consequences. This review gives a comprehensive account of the various advanced imaging modalities used to study COPD, including computed tomography (CT), magnetic resonance imaging (MRI), and the nuclear medicine techniques positron emission tomography (PET) and single-photon emission computed tomography (SPECT). Some more recent developments in imaging technology, including micro-CT, synchrotron imaging, optical coherence tomography (OCT) and electrical impedance tomography (EIT), are also described. The authors identify the pathophysiological insights gained from these techniques, and speculate on the future role of advanced imaging in both clinical and research settings. PMID:25478198

SU-E-T-16: A Comparison of Expected Dwell Times and Dose Variations for NAMD Patients Treated with An Episcleral Brachytherapy Device

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

Hamilton, R; Patel, P; Balaggan, K

2015-06-15

Purpose: To evaluate the variations in dwell times and doses expected when using an episcleral brachytherapy device for treatment of neovascular agerelated macular degeneration (n-AMD) based on accurate imaging modalities Methods: Data from 40 eyes from 40 subjects with known n- AMD acquired through the Distance of Choroid Study (DOCS) conducted at Moorfields Eye Hospital was used to determine the target depth; the distance from the outer scleral surface of the eye, through the choroid, to the apex of the choroidal neovascularization (CNV). Each subject underwent, in triplicate, enhanced-depth Spectral Domain Optical Coherence Tomography (SD-OCT), Swept Source Optical Coherence Tomography,more » (SS-OCT) and Ocular Ultrasound (O-US). These data are the most comprehensive and accurate measurements of the dimensions of the CNV and adjacent layers of the eye for this cohort of patients. During treatment of n-AMD, patients receive a dose of 24Gy to the apex at the target depth. Using the percentage depth dose for a Sr-90 episcleral brachytherapy device, dwell times and doses to the apex were computed to determine the expected variations. Results: The mean target depth and the 95% confidence interval (CI) determined by combining O-US with SD-OCT were 1326 (956,1696)µm and with SS-OCT were 1332 (970,1693)µm. The calculated corresponding mean dwell times and 95% (CI) were 334 (223,445)s and 335 (226,445)s for SD-OCT and SS-OCT determined depths, respectively. The corresponding mean apex dose and 95% (CI) were 24 (35.9,18.0)Gy (SD-OCT) and 24 (35.6,18.1)Gy (SS-OCT). Conclusion: For episcleral brachytherapy treatment of n-AMD, using a patient population average target depth for treatment planning is inadequate, resulting in dose variations of a factor of approximately two over the 95% CI and larger variations for a nontrivial segment of the population. Each patient should have individualized imaging studies to determine the target depth for use in the dwell time calculation. Study was sponsored by Salutaris Medical Devices, Ltd., a subsidiary of Salutaris Medical Devices, Inc. Hamilton and Marsteller are founders of Salutaris Medical Devices, Inc. Drew, McGovern and Vitali are minor equity holders in Salutaris Medical Devices, Inc.« less

Viewing Welds By Computer Tomography

NASA Technical Reports Server (NTRS)

Pascua, Antonio G.; Roy, Jagatjit

1990-01-01

Computer tomography system used to inspect welds for root penetration. Source illuminates rotating welded part with fan-shaped beam of x rays or gamma rays. Detectors in circular array on opposite side of part intercept beam and convert it into electrical signals. Computer processes signals into image of cross section of weld. Image displayed on video monitor. System offers only nondestructive way to check penetration from outside when inner surfaces inaccessible.

Comparison of computed tomography with radiography as a noninvasive diagnostic technique for chronic nasal disease in dogs.

PubMed

Codner, E C; Lurus, A G; Miller, J B; Gavin, P R; Gallina, A; Barbee, D D

1993-04-01

Computed tomography was evaluated as a noninvasive technique for the diagnosis of chronic nasal disease in dogs. Computed tomographic images, radiographs, and histopathologic findings were compared in 11 dogs with chronic nasal disease. Definitive diagnosis was made following traumatic nasal flush, exploratory surgery, or necropsy. The study included 8 dogs with intranasal tumors, 2 dogs with bacterial rhinitis (Pasteurella sp), and 1 dog with mycotic rhinitis (Aspergillus sp). Computed tomography was superior to radiography in defining the extent of the disease process and in differentiating infectious rhinitis from nasal neoplasms. It defined lesions in the palate, nasopharyngeal meatus, maxillary sinus, caudal ethmoturbinates, and periorbital tissues that were difficult to demonstrate by use of conventional radiography. Tumors appeared as space-occupying lesions that obliterated the turbinates, caused deviation of the nasal septum, and eroded bone. Rhinitis appeared as a cavitating lesion that spared the paranasal sinuses, thickened and distorted the turbinates, and widened the meatus. Although morphologically distinct on computed tomographic images, infectious rhinitis and nasal neoplasms could not be differentiated by attenuation measurements or degree of contrast enhancement. Computed tomography appeared to be a reliable, noninvasive technique for the diagnosis of chronic nasal disease in dogs, and a promising alternative to diagnostic techniques currently in use.

Haptics in forensics: the possibilities and advantages in using the haptic device for reconstruction approaches in forensic science.

PubMed

Buck, Ursula; Naether, Silvio; Braun, Marcel; Thali, Michael

2008-09-18

Non-invasive documentation methods such as surface scanning and radiological imaging are gaining in importance in the forensic field. These three-dimensional technologies provide digital 3D data, which are processed and handled in the computer. However, the sense of touch gets lost using the virtual approach. The haptic device enables the use of the sense of touch to handle and feel digital 3D data. The multifunctional application of a haptic device for forensic approaches is evaluated and illustrated in three different cases: the representation of bone fractures of the lower extremities, by traffic accidents, in a non-invasive manner; the comparison of bone injuries with the presumed injury-inflicting instrument; and in a gunshot case, the identification of the gun by the muzzle imprint, and the reconstruction of the holding position of the gun. The 3D models of the bones are generated from the Computed Tomography (CT) images. The 3D models of the exterior injuries, the injury-inflicting tools and the bone injuries, where a higher resolution is necessary, are created by the optical surface scan. The haptic device is used in combination with the software FreeForm Modelling Plus for touching the surface of the 3D models to feel the minute injuries and the surface of tools, to reposition displaced bone parts and to compare an injury-causing instrument with an injury. The repositioning of 3D models in a reconstruction is easier, faster and more precisely executed by means of using the sense of touch and with the user-friendly movement in the 3D space. For representation purposes, the fracture lines of bones are coloured. This work demonstrates that the haptic device is a suitable and efficient application in forensic science. The haptic device offers a new way in the handling of digital data in the virtual 3D space.

[CONE BEAM COMPUTED TOMOGRAPHY IN DIAGNOSTICS OF ODONTOGENIC MAXILLARY SINUSITIS (CASE REPORTS)].

PubMed

Demidova, E; Khurdzidze, G

2017-06-01

Diagnostic studies performed by cone beam computed tomography Morita 3D made possible to obtain high resolution images of hard tissues of upper jawbone and maxillary sinus, to detect bony tissue defects, such as odontogenic cysts, cystogranulomas and granulomas. High-resolution and three dimensional tomographic image reconstructions allowed for optimal and prompt determination of the scope of surgical treatment and planning of effective conservative treatment regimen. Interactive diagnostics helped to estimate cosmetic and functional results of surgical treatment, to prevent the occurrence of surgical complications, and to evaluate the efficacy of conservative treatment. The obtained data contributed to determination of particular applications of cone beam computed tomography in the diagnosis of odontogenic maxillary sinusitis, detection of specific defects with cone beam tomography as the most informative method of diagnosis; as well as to determination of weak and strong sides, and helped to offer mechanisms of x-ray diagnostics to dental surgeons and ENT specialists.

Dynamic contrast enhanced CT in nodule characterization: How we review and report.

PubMed

Qureshi, Nagmi R; Shah, Andrew; Eaton, Rosemary J; Miles, Ken; Gilbert, Fiona J

2016-07-18

Incidental indeterminate solitary pulmonary nodules (SPN) that measure less than 3 cm in size are an increasingly common finding on computed tomography (CT) worldwide. Once identified there are a number of imaging strategies that can be performed to help with nodule characterization. These include interval CT, dynamic contrast enhanced computed tomography (DCE-CT), (18)F-fluorodeoxyglucose positron emission tomography-computed tomography ((18)F-FDG-PET-CT). To date the most cost effective and efficient non-invasive test or combination of tests for optimal nodule characterization has yet to be determined.DCE-CT is a functional test that involves the acquisition of a dynamic series of images of a nodule before and following the administration of intravenous iodinated contrast medium. This article provides an overview of the current indications and limitations of DCE- CT in nodule characterization and a systematic approach to how to perform, analyse and interpret a DCE-CT scan.

Three-dimensional computational model of a blood oxygenator reconstructed from micro-CT scans.

PubMed

D'Onofrio, C; van Loon, R; Rolland, S; Johnston, R; North, L; Brown, S; Phillips, R; Sienz, J

2017-09-01

Cardiopulmonary bypass procedures are one of the most common operations and blood oxygenators are the centre piece for the heart-lung machines. Blood oxygenators have been tested as entire devices but intricate details on the flow field inside the oxygenators remain unknown. In this study, a novel method is presented to analyse the flow field inside oxygenators based on micro Computed Tomography (μCT) scans. Two Hollow Fibre Membrane (HFM) oxygenator prototypes were scanned and three-dimensional full scale models that capture the device-specific fibre distributions are set up for computational fluid dynamics analysis. The blood flow through the oxygenator is modelled as a non-Newtonian fluid. The results were compared against the flow solution through an ideal fibre distribution and show the importance of a uniform distribution of fibres and that the oxygenators analysed are not susceptible to flow directionality as mass flow versus area remain the same. However the pressure drop across the oxygenator is dependent on flow rate and direction. By comparing residence time of blood against the time frame to fully saturate blood with oxygen we highlight the potential of this method as design optimisation tool. In conclusion, image-based reconstruction is found to be a feasible route to assess oxygenator performance through flow modelling. It offers the possibility to review a product as manufactured rather than as designed, which is a valuable insight as a precursor to the approval processes. Finally, the flow analysis presented may be extended, at computational cost, to include species transport in further studies. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Nanocarriers for nuclear imaging and radiotherapy of cancer.

PubMed

Mitra, Amitava; Nan, Anjan; Line, Bruce R; Ghandehari, Hamidreza

2006-01-01

Several nanoscale carriers (nanoparticles, liposomes, water-soluble polymers, micelles and dendrimers) have been developed for targeted delivery of cancer diagnostic and therapeutic agents. These carriers can selectively target cancer sites and carry large payloads, thereby improving cancer detection and therapy effectiveness. Further, the combination of newer nuclear imaging techniques providing high sensitivity and spatial resolution such as dual modality imaging with positron emission tomography/computed tomography (PET/CT) and use of nanoscale devices to carry diagnostic and therapeutic radionuclides with high target specificity can enable more accurate detection, staging and therapy planning of cancer. The successful clinical applications of radiolabeled monoclonal antibodies for cancer detection and therapy bode well for the future of nanoscale carrier systems in clinical oncology. Several radiolabeled multifunctional nanocarriers have been effective in detecting and treating cancer in animal models. Nonetheless, further preclinical, clinical and long-term toxicity studies will be required to translate this technology to the care of patients with cancer. The objective of this review is to present a brief but comprehensive overview of the various nuclear imaging techniques and the use of nanocarriers to deliver radionuclides for the diagnosis and therapy of cancer.

Multi-GPU parallel algorithm design and analysis for improved inversion of probability tomography with gravity gradiometry data

NASA Astrophysics Data System (ADS)

Hou, Zhenlong; Huang, Danian

2017-09-01

In this paper, we make a study on the inversion of probability tomography (IPT) with gravity gradiometry data at first. The space resolution of the results is improved by multi-tensor joint inversion, depth weighting matrix and the other methods. Aiming at solving the problems brought by the big data in the exploration, we present the parallel algorithm and the performance analysis combining Compute Unified Device Architecture (CUDA) with Open Multi-Processing (OpenMP) based on Graphics Processing Unit (GPU) accelerating. In the test of the synthetic model and real data from Vinton Dome, we get the improved results. It is also proved that the improved inversion algorithm is effective and feasible. The performance of parallel algorithm we designed is better than the other ones with CUDA. The maximum speedup could be more than 200. In the performance analysis, multi-GPU speedup and multi-GPU efficiency are applied to analyze the scalability of the multi-GPU programs. The designed parallel algorithm is demonstrated to be able to process larger scale of data and the new analysis method is practical.

Characterization of PET preforms using spectral domain optical coherence tomography

NASA Astrophysics Data System (ADS)

Hosseiny, Hamid; Ferreira, Manuel João.; Martins, Teresa; Carmelo Rosa, Carla

2013-11-01

Polyethylene terephthalate (PET) preforms are massively produced nowadays with the purpose of producing food and beverages packaging and liquid containers. Some varieties of these preforms are produced as multilayer structures, where very thin inner film(s) act as a barrier for nutrients leakage. The knowledge of the thickness of this thin inner layer is important in the production line. The quality control of preforms production requires a fast approach and normally the thickness control is performed by destructive means out of the production line. A spectral domain optical coherence tomography (SD-OCT) method was proposed to examine the thin layers in real time. This paper describes a nondestructive approach and all required signal processing steps to characterize the thin inner layers and also to improve the imaging speed and the signal to noise ratio. The algorithm was developed by using graphics processing unit (GPU) with computer unified device architecture (CUDA). This GPU-accelerated white light interferometry technique nondestructively assesses the samples and has high imaging speed advantage, overcoming the bottlenecks in PET performs quality control.

Comparative study of cranial anthropometric measurement by traditional calipers to computed tomography and three-dimensional photogrammetry.

PubMed

Mendonca, Derick A; Naidoo, Sybill D; Skolnick, Gary; Skladman, Rachel; Woo, Albert S

2013-07-01

Craniofacial anthropometry by direct caliper measurements is a common method of quantifying the morphology of the cranial vault. New digital imaging modalities including computed tomography and three-dimensional photogrammetry are similarly being used to obtain craniofacial surface measurements. This study sought to compare the accuracy of anthropometric measurements obtained by calipers versus 2 methods of digital imaging.Standard anterior-posterior, biparietal, and cranial index measurements were directly obtained on 19 participants with an age range of 1 to 20 months. Computed tomographic scans and three-dimensional photographs were both obtained on each child within 2 weeks of the clinical examination. Two analysts measured the anterior-posterior and biparietal distances on the digital images. Measures of reliability and bias between the modalities were calculated and compared.Caliper measurements were found to underestimate the anterior-posterior and biparietal distances as compared with those of the computed tomography and the three-dimensional photogrammetry (P < 0.001). Cranial index measurements between the computed tomography and the calipers differed by up to 6%. The difference between the 2 modalities was statistically significant (P = 0.021). The biparietal and cranial index results were similar between the digital modalities, but the anterior-posterior measurement was greater with the three-dimensional photogrammetry (P = 0.002). The coefficients of variation for repeated measures based on the computed tomography and the three-dimensional photogrammetry were 0.008 and 0.007, respectively.In conclusion, measurements based on digital modalities are generally reliable and interchangeable. Caliper measurements lead to underestimation of anterior-posterior and biparietal values compared with digital imaging.

Imaging of a parapharyngeal hemangiopericytoma. Radioimmunoscintigraphy (SPECT) with indium-111-labeled anti-CEA antibody, and comparison to digital subtraction angiography, computed tomography, and immunohistochemistry

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

Kairemo, K.J.; Hopsu, E.V.; Melartin, E.J.

1991-01-01

A 27-year-old male patient with a parapharyngeal hemangiopericytoma was investigated radiologically with orthopantomography, computed tomography, and digital subtraction angiography before the operation. Because a malignancy was suspected, the patient was imaged with gamma camera using radiolabeled monoclonal anticarcinoembryonal antigen antibody including single photon emission computed tomography. The radioantibody accumulated strongly into the neoplasm. Tumor to background ratio was 2.2. Samples of the excised tumor were stained immunohistochemically for desmin, vimentin, muscle actin, cytokeratin, CEA (carcinoembryonic antigen), and factor VIII. They showed that the antibody uptake was of unspecific nature and not due to CEA expression in the tumor.

Normal Variants and Pitfalls Encountered in PET Assessment of Gynecologic Malignancies.

PubMed

Yu, Jian Q; Doss, Mohan; Alpaugh, R Katherine

2018-04-01

Combined PET/computed tomography is used for oncological indications. PET/computed tomography benefits from the metabolic information of PET and the anatomic localization of computed tomography. The integrated scanner provides data with accurate registration of anatomy and molecular information. Many physiologic conditions, normal variants, and benign lesions within the pelvis and the body can cause confusion and uncertainty. False-negative results owing to low 18 F-fluorodeoxyglucose uptake from the tumor can produce diagnostic challenges and inaccurate conclusions. This article reviews normal variants and potential pitfalls encountered in PET assessment of gynecologic malignancies to provide useful information for the referring and reporting physicians. Copyright © 2017 Elsevier Inc. All rights reserved.

Computed Tomography and Thermography Increases CMC Material and Process Development Efficiency and Testing Effectiveness

NASA Technical Reports Server (NTRS)

Effinger, Michael; Beshears, Ron; Hufnagle, David; Walker, James; Russell, Sam; Stowell, Bob; Myers, David

2002-01-01

Nondestructive characterization techniques have been used to steer development and testing of CMCs. Computed tomography is used to determine the volumetric integrity of the CMC plates and components. Thermography is used to determine the near surface integrity of the CMC plates and components. For process and material development, information such as density uniformity, part delamination, and dimensional tolerance conformity is generated. The information from the thermography and computed tomography is correlated and then specimen cutting maps are superimposed on the thermography images. This enables for tighter data and potential explanation of off nominal test data. Examples of nondestructive characterization utilization to make decisions in process and material development and testing are presented.

UNSEDATED COMPUTED TOMOGRAPHY FOR DIAGNOSIS OF PELVIC CANAL OBSTRUCTION IN A LEOPARD GECKO (EUBLEPHARIS MACULARIUS).

PubMed

DeCourcy, Kelly; Hostnik, Eric T; Lorbach, Josh; Knoblaugh, Sue

2016-12-01

An adult leopard gecko ( Eublepharis macularius ) presented for lethargy, hyporexia, weight loss, decreased passage of waste, and a palpable caudal coelomic mass. Computed tomography showed a heterogeneous hyperattenuating (∼143 Hounsfield units) structure within the right caudal coelom. The distal colon-coprodeum lumen or urinary bladder was hypothesized as the most likely location for the heterogeneous structure. Medical support consisted of warm water and lubricant enema, as well as a heated environment. Medical intervention aided the passage of a plug comprised centrally of cholesterol and urates with peripheral stratified layers of fibrin, macrophages, heterophils, and bacteria. Within 24 hr, a follow-up computed tomography scan showed resolution of the pelvic canal plug.

Evaluation of dosimetry and image of very low-dose computed tomography attenuation correction for pediatric positron emission tomography/computed tomography: phantom study

NASA Astrophysics Data System (ADS)

Bahn, Y. K.; Park, H. H.; Lee, C. H.; Kim, H. S.; Lyu, K. Y.; Dong, K. R.; Chung, W. K.; Cho, J. H.

2014-04-01

In this study, phantom was used to evaluate attenuation correction computed tomography (CT) dose and image in case of pediatric positron emission tomography (PET)/CT scan. Three PET/CT scanners were used along with acryl phantom in the size for infant and ion-chamber dosimeter. The CT image acquisition conditions were changed from 10 to 20, 40, 80, 100 and 160 mA and from 80 to 100, 120 and 140 kVp, which aimed at evaluating penetrate dose and computed tomography dose indexvolume (CTDIvol) value. And NEMA PET Phantom™ was used to obtain PET image under the same CT conditions in order to evaluate each attenuation-corrected PET image based on standard uptake value (SUV) value and signal-to-noise ratio (SNR). In general, the penetrate dose was reduced by around 92% under the minimum CT conditions (80 kVp and 10 mA) with the decrease in CTDIvol value by around 88%, compared with the pediatric abdomen CT conditions (100 kVp and 100 mA). The PET image with its attenuation corrected according to each CT condition showed no change in SUV value and no influence on the SNR. In conclusion, if the minimum dose CT that is properly applied to body of pediatric patient is corrected for attenuation to ensure that the effective dose is reduced by around 90% or more compared with that for adult patient, this will be useful to reduce radiation exposure level.

Fusion Imaging: A Novel Staging Modality in Testis Cancer

PubMed Central

Sterbis, Joseph R.; Rice, Kevin R.; Javitt, Marcia C.; Schenkman, Noah S.; Brassell, Stephen A.

2010-01-01

Objective: Computed tomography and chest radiographs provide the standard imaging for staging, treatment, and surveillance of testicular germ cell neoplasms. Positron emission tomography has recently been utilized for staging, but is somewhat limited in its ability to provide anatomic localization. Fusion imaging combines the metabolic information provided by positron emission tomography with the anatomic precision of computed tomography. To the best of our knowledge, this represents the first study of the effectiveness using fusion imaging in evaluation of patients with testis cancer. Methods: A prospective study of 49 patients presenting to Walter Reed Army Medical Center with testicular cancer from 2003 to 2009 was performed. Fusion imaging was compared with conventional imaging, tumor markers, pathologic results, and clinical follow-up. Results: There were 14 true positives, 33 true negatives, 1 false positive, and 1 false negative. Sensitivity, specificity, positive predictive value, and negative predictive value were 93.3, 97.0, 93.3, and 97.0% respectively. In 11 patient scenarios, fusion imaging differed from conventional imaging. Utility was found in superior lesion detection compared to helical computed tomography due to anatomical/functional image co-registration, detection of micrometastasis in lymph nodes (pathologic nodes < 1cm), surveillance for recurrence post-chemotherapy, differentiating fibrosis from active disease in nodes < 2.5cm, and acting as a quality assurance measure to computed tomography alone. Conclusions: In addition to demonstrating a sensitivity and specificity comparable or superior to conventional imaging, fusion imaging shows promise in providing additive data that may assist in clinical decision-making. PMID:21103077

Fusion imaging: a novel staging modality in testis cancer.

PubMed

Sterbis, Joseph R; Rice, Kevin R; Javitt, Marcia C; Schenkman, Noah S; Brassell, Stephen A

2010-11-05

Computed tomography and chest radiographs provide the standard imaging for staging, treatment, and surveillance of testicular germ cell neoplasms. Positron emission tomography has recently been utilized for staging, but is somewhat limited in its ability to provide anatomic localization. Fusion imaging combines the metabolic information provided by positron emission tomography with the anatomic precision of computed tomography. To the best of our knowledge, this represents the first study of the effectiveness using fusion imaging in evaluation of patients with testis cancer. A prospective study of 49 patients presenting to Walter Reed Army Medical Center with testicular cancer from 2003 to 2009 was performed. Fusion imaging was compared with conventional imaging, tumor markers, pathologic results, and clinical follow-up. There were 14 true positives, 33 true negatives, 1 false positive, and 1 false negative. Sensitivity, specificity, positive predictive value, and negative predictive value were 93.3, 97.0, 93.3, and 97.0% respectively. In 11 patient scenarios, fusion imaging differed from conventional imaging. Utility was found in superior lesion detection compared to helical computed tomography due to anatomical/functional image co-registration, detection of micrometastasis in lymph nodes (pathologic nodes < 1cm), surveillance for recurrence post-chemotherapy, differentiating fibrosis from active disease in nodes < 2.5cm, and acting as a quality assurance measure to computed tomography alone. In addition to demonstrating a sensitivity and specificity comparable or superior to conventional imaging, fusion imaging shows promise in providing additive data that may assist in clinical decision-making.

Computational adaptive optics for broadband interferometric tomography of tissues and cells

NASA Astrophysics Data System (ADS)

Adie, Steven G.; Mulligan, Jeffrey A.

2016-03-01

Adaptive optics (AO) can shape aberrated optical wavefronts to physically restore the constructive interference needed for high-resolution imaging. With access to the complex optical field, however, many functions of optical hardware can be achieved computationally, including focusing and the compensation of optical aberrations to restore the constructive interference required for diffraction-limited imaging performance. Holography, which employs interferometric detection of the complex optical field, was developed based on this connection between hardware and computational image formation, although this link has only recently been exploited for 3D tomographic imaging in scattering biological tissues. This talk will present the underlying imaging science behind computational image formation with optical coherence tomography (OCT) -- a beam-scanned version of broadband digital holography. Analogous to hardware AO (HAO), we demonstrate computational adaptive optics (CAO) and optimization of the computed pupil correction in 'sensorless mode' (Zernike polynomial corrections with feedback from image metrics) or with the use of 'guide-stars' in the sample. We discuss the concept of an 'isotomic volume' as the volumetric extension of the 'isoplanatic patch' introduced in astronomical AO. Recent CAO results and ongoing work is highlighted to point to the potential biomedical impact of computed broadband interferometric tomography. We also discuss the advantages and disadvantages of HAO vs. CAO for the effective shaping of optical wavefronts, and highlight opportunities for hybrid approaches that synergistically combine the unique advantages of hardware and computational methods for rapid volumetric tomography with cellular resolution.

Asymptomatic Emphysematous Pyelonephritis - Positron Emission Tomography Computerized Tomography Aided Diagnostic and Therapeutic Elucidation

PubMed Central

Pathapati, Deepti; Shinkar, Pawan Gulabrao; kumar, Satya Awadhesh; Jha; Dattatreya, Palanki Satya; Chigurupati, Namrata; Chigurupati, Mohana Vamsy; Rao, Vatturi Venkata Satya Prabhakar

2017-01-01

The authors report an interesting coincidental unearthing by 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) of a potentially serious medical condition of emphysematous pyelonephritis in a case of nasopharyngeal carcinoma. The management by conservative ureteric stenting and antibiotics was done with gratifying clinical outcome. PMID:28242985

[Multispiral computed tomographic semiotics of laryngeal cancer].

PubMed

Vasil'ev, P V; Iudin, A L; Sdvizhkov, A M; Kozhanov, L G

2007-01-01

Multispiral computed tomography (MSCT) with intravenous bolus contrasting is a currently available method for radiodiagnosis of laryngeal cancer. MSCT is of much higher informative value in estimating the extent of a tumorous lesion than the traditional radiodiagnostic techniques: linear tomography, lateral X-ray study, roentgenoscopy and roentgenography of the laryngopharynx and esophagus with barium meal.

Diffuse cylindrical bronchiectasis due to eosinophilic bronchopneumopathy in a dog

PubMed Central

Meler, Erika; Pressler, Barrak M.; Heng, Hock Gan; Baird, Debra K.

2010-01-01

A miniature pinscher-cross was evaluated for chronic coughing. Computed tomography and bronchoscopy revealed severe, diffuse, cylindrical bronchiectasis secondary to eosinophilic bronchopneumopathy. Computed tomography is the gold standard for diagnosis of bronchiectasis in humans, and should be further investigated in dogs as a means of characterizing severity and pattern of disease. PMID:20885829

Abernethy malformation with portal vein aneurysm in a child.

PubMed

Chandrashekhara, Sheragaru H; Bhalla, Ashu Seith; Gupta, Arun Kumar; Vikash, C S; Kabra, Susheel Kumar

2011-01-01

Abernethy malformation is an extremely rare anomaly of the splanchnic venous system. We describe multidetector computed tomography findings of an incidentally detected Abernethy malformation with portal vein aneurysm in a two-and-half-year old child. The computed tomography scan was performed for the evaluation of respiratory distress, poor growth, and loss of appetite.

Computed tomography guided localization of clinically occult breast carcinoma-the ''N'' skin guide

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

Kopans, D.B.; Meyer, J.E.

1982-10-01

Standard computed tomography (CT) can be used for the three-dimensional localization of clinically occult suspicious breast lesions whose exact position cannot be determined by standard mammographic views. A method is described that facilitates accurate preoperative needle localization using CT guidance, once the position of these lesions is defined.

Presence of gas in left ventricle due to infective endocarditis.

PubMed

Laiq, Zenab; Yarmohammadi, Hirad; Nabeel, Yassar; Adatya, Sirtaz

2016-01-01

Gas in myocardium is a rare manifestation of infective endocarditis caused by gas producing bacteria. We present a case of infective endocarditis caused by Citrobacter Koseri initially diagnosed by computed tomography and confirmed with transesophageal echocardiogram. Copyright © 2016 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.

Use of Computed Tomography Imaging for Qualifying Coarse Roots, Rhizomes, Peat, and Particle Densities in Marsh Soils

EPA Science Inventory

Computed tomography (CT) imaging has been used to describe and quantify subtidal, benthic animals such as polychaetes, amphipods, and shrimp. Here, for the first time, CT imaging is used to successfully quantify wet mass of coarse roots, rhizomes, and peat in cores collected from...

Use of Computer-Aided Tomography (CT) Imaging for Quantifying Coarse Roots, Rhizomes, Peat, and Particle Densities in Marsh Soils

EPA Science Inventory

Computer-aided Tomography (CT) imaging was utilized to quantify wet mass of coarse roots, rhizomes, and peat in cores collected from organic-rich (Jamaica Bay, NY) and mineral (North Inlet, SC) Spartina alterniflora soils. Calibration rods composed of materials with standard dens...

APPLICATION OF COMPUTER-AIDED TOMOGRAPHY TO VISUALIZE AND QUANTIFY BIOGENIC STRUCTURES IN MARINE SEDIMENTS

EPA Science Inventory

We used computer-aided tomography (CT) for 3D visualization and 2D analysis of

marine sediment cores from 3 stations (at 10, 75 and 118 m depths) with different environmental

impact. Biogenic structures such as tubes and burrows were quantified and compared among st...

Micro-computed tomography of pupal metamorphosis in the solitary bee Megachile rotundata

USDA-ARS?s Scientific Manuscript database

Insect metamorphosis involves a complex change in form and function, but most of these changes are internal and treated as a black box. In this study, we examined development of the solitary bee, Megachile rotundata, using micro-computed tomography (µCT) and digital volume analysis. We describe deve...

Reliability of voxel gray values in cone beam computed tomography for preoperative implant planning assessment.

PubMed

Parsa, Azin; Ibrahim, Norliza; Hassan, Bassam; Motroni, Alessandro; van der Stelt, Paul; Wismeijer, Daniel

2012-01-01

To assess the reliability of cone beam computed tomography (CBCT) voxel gray value measurements using Hounsfield units (HU) derived from multislice computed tomography (MSCT) as a clinical reference (gold standard). Ten partially edentulous human mandibular cadavers were scanned by two types of computed tomography (CT) modalities: multislice CT and cone beam CT. On MSCT scans, eight regions of interest (ROI) designating the site for preoperative implant placement were selected in each mandible. The datasets from both CT systems were matched using a three-dimensional (3D) registration algorithm. The mean voxel gray values of the region around the implant sites were compared between MSCT and CBCT. Significant differences between the mean gray values obtained by CBCT and HU by MSCT were found. In all the selected ROIs, CBCT showed higher mean values than MSCT. A strong correlation (R=0.968) between mean voxel gray values of CBCT and mean HU of MSCT was determined. Voxel gray values from CBCT deviate from actual HU units. However, a strong linear correlation exists, which may permit deriving actual HU units from CBCT using linear regression models.

Renal vein thrombosis mimicking urinary calculus: a dilemma of diagnosis.

PubMed

Wang, Yimin; Chen, Shanwen; Wang, Wei; Liu, Jianyong; Jin, Baiye

2015-07-02

Renal vein thrombosis (RVT) with flank pain, and hematuria, is often mistaken with renal colic originating from ureteric or renal calculus. Especially in young and otherwise healthy patients, clinicians are easily misled by clinical presentation and calcified RVT. A 38-year-old woman presented with flank pain and hematuria suggestive of renal calculus on ultrasound. She underwent extracorporeal shock wave lithotripsy that failed, leading to the recommendation that percutaneous lithotomy was necessary to remove the renal calculus. In preoperative view of the unusual shape of the calculus without hydronephrosis, noncontrast computed tomography was taken and demonstrated left ureteric calculus. However computed tomography angiography revealed, to our surprise, a calcified RVT that was initially thought to be a urinary calculus. This case shows that a calcified RVT might mimic a urinary calculus on conventional ultrasonography and ureteric calculus on noncontrast computed tomography. Subsequent computed tomography angiography disclosed that a calcified RVT caused the imaging findings, thus creating a potentially dangerous clinical pitfall. Hence, it is suggested that the possibility of a RVT needs to be considered in the differential diagnosis whenever one detects an uncommon shape for a urinary calculus.

Inflammatory Pseudotumor-Like Follicular Dendritic Cell Sarcoma of the Spleen: Computed Tomography Imaging Characteristics in 5 Patients.

PubMed

Li, Xiumei; Shi, Zhenshan; You, Ruixiong; Li, Yueming; Cao, Dairong; Lin, Renjie; Huang, Xinming

The purpose of this study was to retrospectively review the computed tomography (CT) and clinicopathological characteristics of inflammatory pseudotumor (IPT)-like follicular dendritic cell sarcoma (FDCS) of the spleen in 5 patients. Clinical, pathologic, and CT imaging findings of 5 patients with IPT-like FDCS of the spleen were reviewed and analyzed. Computed tomography imaging and pathologic features were compared. Abdominal unenhanced CT revealed a well-defined hypodense mass in the spleen with complex internal architecture with focal necrosis and/or speckle-strip calcification. On postcontrast CT, slightly delayed enhancement was observed in 5 cases. Four patients had a normalized spleen. The fourth patient had lung metastasis. The fifth patient had 2 relatively small lesions as well as metastases to the spine. Computed tomography imaging features of IPT-like FDCS of the spleen are distinctly different from other hypovascular splenic neoplasm; however, the definitive diagnosis requires further confirmation with needle biopsy or surgery. Inflammatory pseudotumor-like FDCS of the spleen should be suggested by using the CT imaging features of the splenic mass with evidence of metastatic disease.

Malignant head and neck tumours in Radiology Department JPMC Karachi -- a tertiary care experience.

PubMed

Kadri, Shazia; Uddin, Sami; Ahmed, Naveed; Mahmood, Tariq

2015-08-01

To study age, gender and sites of malignant head and neck tumours on contrast-enhanced computed tomography and to elucidate its role. The retrospective study was conducted at the Jinnah Postgraduate Medical Centre, Karachi, and comprised data of patients with histologically proven malignant head and neck tumours reporting from February 2013 to February 2014. Contrast enhanced computed tomography with puffed cheek technique was done in cases of oral cancer, while routine contrast computed tomography was done in cases of other head and neck tumours. SPSS 19 was used for statistical analysis. A total of 100 biopsy-proven cases of malignant tumours comprised the study sample. The male: female ratio was 1.5:1 with an overall mean age of 46.4±16-76 years. . The most common histopathologically proven tumour was squamous cell carcinoma affecting oral mucosa 43(43%), followed by larynx 27(27%) and pharynx 10(10%) . Oral squamous cell carcinoma was the commonest tumour. Compute tomography scan with puffed cheek technique played a beneficial role in locating the site of primary tumour.

Imaging of the midpalatal suture in a porcine model: flat-panel volume computed tomography compared with multislice computed tomography.

PubMed

Hahn, Wolfram; Fricke-Zech, Susanne; Fialka-Fricke, Julia; Dullin, Christian; Zapf, Antonia; Gruber, Rudolf; Sennhenn-kirchner, Sabine; Kubein-Meesenburg, Dietmar; Sadat-Khonsari, Reza

2009-09-01

An investigation was conducted to compare the image quality of prototype flat-panel volume computed tomography (fpVCT) and multislice computed tomography (MSCT) of suture structures. Bone samples were taken from the midpalatal suture of 5 young (16 weeks) and 5 old (200 weeks) Sus scrofa domestica and fixed in formalin solution. An fpVCT prototype and an MSCT were used to obtain images of the specimens. The facial reformations were assessed by 4 observers using a 1 (excellent) to 5 (poor) rating scale for the weighted criteria visualization of the suture structure. A linear mixed model was used for statistical analysis. Results with P < .05 were considered to be statistically significant. The visualization of the suture of young specimens was significantly better than that of older animals (P < .001). The visualization of the suture with fpVCT was significantly better than that with MSCT (P < .001). Compared with MSCT, fpVCT produces superior results in the visualization of the midpalatal suture in a Sus scrofa domestica model.

Spectrally resolving and scattering-compensated x-ray luminescence/fluorescence computed tomography

PubMed Central

Cong, Wenxiang; Shen, Haiou; Wang, Ge

2011-01-01

The nanophosphors, or other similar materials, emit near-infrared (NIR) light upon x-ray excitation. They were designed as optical probes for in vivo visualization and analysis of molecular and cellular targets, pathways, and responses. Based on the previous work on x-ray fluorescence computed tomography (XFCT) and x-ray luminescence computed tomography (XLCT), here we propose a spectrally-resolving and scattering-compensated x-ray luminescence/fluorescence computed tomography (SXLCT or SXFCT) approach to quantify a spatial distribution of nanophosphors (other similar materials or chemical elements) within a biological object. In this paper, the x-ray scattering is taken into account in the reconstruction algorithm. The NIR scattering is described in the diffusion approximation model. Then, x-ray excitations are applied with different spectra, and NIR signals are measured in a spectrally resolving fashion. Finally, a linear relationship is established between the nanophosphor distribution and measured NIR data using the finite element method and inverted using the compressive sensing technique. The numerical simulation results demonstrate the feasibility and merits of the proposed approach. PMID:21721815

Radiolabeling, whole-body single photon emission computed tomography/computed tomography imaging, and pharmacokinetics of carbon nanohorns in mice

PubMed Central

Zhang, Minfang; Jasim, Dhifaf A; Ménard-Moyon, Cécilia; Nunes, Antonio; Iijima, Sumio; Bianco, Alberto; Yudasaka, Masako; Kostarelos, Kostas

2016-01-01

In this work, we report that the biodistribution and excretion of carbon nanohorns (CNHs) in mice are dependent on their size and functionalization. Small-sized CNHs (30–50 nm; S-CNHs) and large-sized CNHs (80–100 nm; L-CNHs) were chemically functionalized and radiolabeled with [111In]-diethylenetriaminepentaacetic acid and intravenously injected into mice. Their tissue distribution profiles at different time points were determined by single photon emission computed tomography/computed tomography. The results showed that the S-CNHs circulated longer in blood, while the L-CNHs accumulated faster in major organs like the liver and spleen. Small amounts of S-CNHs- and L-CNHs were excreted in urine within the first few hours postinjection, followed by excretion of smaller quantities within the next 48 hours in both urine and feces. The kinetics of excretion for S-CNHs were more rapid than for L-CNHs. Both S-CNH and L-CNH material accumulated mainly in the liver and spleen; however, S-CNH accumulation in the spleen was more prominent than in the liver. PMID:27524892

Clinical and Radiographic Response of Extramedullary Leukemia in Patients Treated With Gemtuzumab Ozogamicin.

PubMed

McNeil, Michael J; Parisi, Marguerite T; Hijiya, Nobuko; Meshinchi, Soheil; Cooper, Todd; Tarlock, Katherine

2018-05-04

Extramedullary leukemia (EML) is common in pediatric acute leukemia and can present at diagnosis or relapse. CD33 is detected on the surface of myeloid blasts in many patients with acute myelogenous leukemia and is the target of the antibody drug conjugate gemtuzumab ozogamicin (GO). Here we present 2 patients with CD33 EML treated with GO. They achieved significant response, with reduction of EML on both clinical and radiographic exams, specifically fluorine fluorodeoxyglucose positron emission tomography/computed tomography, demonstrating potential for targeted therapy with GO as a means of treating EML in patients with CD33 leukemia and the utility of fluorine fluorodeoxyglucose positron emission tomography/computed tomography monitoring in EML.

68Gallium-Arginine-Glycine-Aspartic Acid and 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in Chondroblastic Osteosarcoma of the Skull.

PubMed

Orunmuyi, Akintunde; Modiselle, Moshe; Lengana, Thabo; Ebenhan, Thomas; Vorster, Mariza; Sathekge, Mike

2017-09-01

We report the case of a 32 year-old male with Chondroblastic Osteosarcoma of the skull, which was imaged with both 18 [F]fluorodeoxyglucose ( 18 F-FDG) positron emission tomography/computed tomography (PET/CT) and 68 Gallium-arginine-glycine-aspartic acid ( 68 Ga-RGD) PET/CT. The 18 F-FDG PET/CT did not demonstrate the tumour, whereas the 68 Ga-RGD PET/CT clearly depicted a left-sided frontal tumour. 68 Ga-RGD PET/CT may be a clinically useful imaging modality for early detection of recurrent osteosarcoma, considering the limitations of 18 F-FDG PET in a setting of low glycolytic activity.

Nonmetastatic Castration-resistant Prostate Cancer: A Modern Perspective.

PubMed

Cancian, Madeline; Renzulli, Joseph F

2018-06-01

Nonmetastatic castration-resistant prostate cancer (nmCRPC) presents a challenge to urologists as currently there are no Food and Drug Administration-approved therapies. However, there are new imaging modalities, including fluciclovine positron emission tomography-computed tomography and Ga-PSMA (prostate specific membrane antigent) positron emission tomography-computed tomography, which are improving accuracy of diagnosis. With improved imaging, we are better able to target therapy. Today there are 3 ongoing clinical trials studying second-generation antiandrogens in nmCRPC, which hold the promise of a new treatment paradigm. In this article, we will review the new imaging techniques and the rationale behind novel treatment modalities in nmCRPC. Copyright © 2018 Elsevier Inc. All rights reserved.

Optical Coherence Tomography of the Tympanic Membrane and Middle Ear: A Review.

PubMed

Tan, Hsern Ern Ivan; Santa Maria, Peter Luke; Wijesinghe, Philip; Francis Kennedy, Brendan; Allardyce, Benjamin James; Eikelboom, Robert Henry; Atlas, Marcus David; Dilley, Rodney James

2018-05-01

Objective To evaluate the recent developments in optical coherence tomography (OCT) for tympanic membrane (TM) and middle ear (ME) imaging and to identify what further development is required for the technology to be integrated into common clinical use. Data Sources PubMed, Embase, Google Scholar, Scopus, and Web of Science. Review Methods A comprehensive literature search was performed for English language articles published from January 1966 to January 2018 with the keywords "tympanic membrane or middle ear,"optical coherence tomography," and "imaging." Conclusion Conventional imaging techniques cannot adequately resolve the microscale features of TM and ME, sometimes necessitating diagnostic exploratory surgery in challenging otologic pathology. As a high-resolution noninvasive imaging technique, OCT offers promise as a diagnostic aid for otologic conditions, such as otitis media, cholesteatoma, and conductive hearing loss. Using OCT vibrometry to image the nanoscale vibrations of the TM and ME as they conduct acoustic waves may detect the location of ossicular chain dysfunction and differentiate between stapes fixation and incus-stapes discontinuity. The capacity of OCT to image depth and thickness at high resolution allows 3-dimensional volumetric reconstruction of the ME and has potential use for reconstructive tympanoplasty planning and the follow-up of ossicular prostheses. Implications for Practice To achieve common clinical use beyond these initial discoveries, future in vivo imaging devices must feature low-cost probe or endoscopic designs and faster imaging speeds and demonstrate superior diagnostic utility to computed tomography and magnetic resonance imaging. While such technology has been available for OCT, its translation requires focused development through a close collaboration between engineers and clinicians.

Optimization of a Solid-State Electron Spin Qubit Using Gate Set Tomography (Open Access, Publisher’s Version)

DTIC Science & Technology

2016-10-13

enielse@sandia.gov and a.morello@unsw.edu.au Keywords: quantum computing , silicon, tomography Supplementarymaterial for this article is available online...Abstract State of the art qubit systems are reaching the gatefidelities required for scalable quantum computation architectures. Further improvements in...and addressedwhen the qubit is usedwithin a fault-tolerant quantum computation scheme. 1. Introduction One of themain challenges in the physical

Adaptive-optics optical coherence tomography processing using a graphics processing unit.

PubMed

Shafer, Brandon A; Kriske, Jeffery E; Kocaoglu, Omer P; Turner, Timothy L; Liu, Zhuolin; Lee, John Jaehwan; Miller, Donald T

2014-01-01

Graphics processing units are increasingly being used for scientific computing for their powerful parallel processing abilities, and moderate price compared to super computers and computing grids. In this paper we have used a general purpose graphics processing unit to process adaptive-optics optical coherence tomography (AOOCT) images in real time. Increasing the processing speed of AOOCT is an essential step in moving the super high resolution technology closer to clinical viability.

High-Resolution Computed Tomography and Pulmonary Function Findings of Occupational Arsenic Exposure in Workers.

PubMed

Ergün, Recai; Evcik, Ender; Ergün, Dilek; Ergan, Begüm; Özkan, Esin; Gündüz, Özge

2017-05-05

The number of studies where non-malignant pulmonary diseases are evaluated after occupational arsenic exposure is very few. To investigate the effects of occupational arsenic exposure on the lung by high-resolution computed tomography and pulmonary function tests. Retrospective cross-sectional study. In this study, 256 workers with suspected respiratory occupational arsenic exposure were included, with an average age of 32.9±7.8 years and an average of 3.5±2.7 working years. Hair and urinary arsenic levels were analysed. High-resolution computed tomography and pulmonary function tests were done. In workers with occupational arsenic exposure, high-resolution computed tomography showed 18.8% pulmonary involvement. In pulmonary involvement, pulmonary nodule was the most frequently seen lesion (64.5%). The other findings of pulmonary involvement were 18.8% diffuse interstitial lung disease, 12.5% bronchiectasis, and 27.1% bullae-emphysema. The mean age of patients with pulmonary involvement was higher and as they smoked more. The pulmonary involvement was 5.2 times higher in patients with skin lesions because of arsenic. Diffusing capacity of lung for carbon monoxide was significantly lower in patients with pulmonary involvement. Besides lung cancer, chronic occupational inhalation of arsenic exposure may cause non-malignant pulmonary findings such as bronchiectasis, pulmonary nodules and diffuse interstitial lung disease. So, in order to detect pulmonary involvement in the early stages, workers who experience occupational arsenic exposure should be followed by diffusion test and high-resolution computed tomography.

The Influence of Reconstruction Kernel on Bone Mineral and Strength Estimates Using Quantitative Computed Tomography and Finite Element Analysis.

PubMed

Michalski, Andrew S; Edwards, W Brent; Boyd, Steven K

2017-10-17

Quantitative computed tomography has been posed as an alternative imaging modality to investigate osteoporosis. We examined the influence of computed tomography convolution back-projection reconstruction kernels on the analysis of bone quantity and estimated mechanical properties in the proximal femur. Eighteen computed tomography scans of the proximal femur were reconstructed using both a standard smoothing reconstruction kernel and a bone-sharpening reconstruction kernel. Following phantom-based density calibration, we calculated typical bone quantity outcomes of integral volumetric bone mineral density, bone volume, and bone mineral content. Additionally, we performed finite element analysis in a standard sideways fall on the hip loading configuration. Significant differences for all outcome measures, except integral bone volume, were observed between the 2 reconstruction kernels. Volumetric bone mineral density measured using images reconstructed by the standard kernel was significantly lower (6.7%, p < 0.001) when compared with images reconstructed using the bone-sharpening kernel. Furthermore, the whole-bone stiffness and the failure load measured in images reconstructed by the standard kernel were significantly lower (16.5%, p < 0.001, and 18.2%, p < 0.001, respectively) when compared with the image reconstructed by the bone-sharpening kernel. These data suggest that for future quantitative computed tomography studies, a standardized reconstruction kernel will maximize reproducibility, independent of the use of a quantitative calibration phantom. Copyright © 2017 The International Society for Clinical Densitometry. Published by Elsevier Inc. All rights reserved.

Assessment of cardiovascular risk profile based on measurement of tophus volume in patients with gout.

PubMed

Lee, Kyung-Ann; Ryu, Se-Ri; Park, Seong-Jun; Kim, Hae-Rim; Lee, Sang-Heon

2018-05-01

Hyperuricemia and gout are associated with increased risk of cardiovascular disease and metabolic syndrome. The aim of this study was to evaluate the correlation of total tophus volumes, measured using dual-energy computed tomography, with cardiovascular risk and the presence of metabolic syndrome. Dual-energy computed tomography datasets from 91 patients with a diagnosis of gout were analyzed retrospectively. Patients who received urate lowering therapy were excluded to avoid the effect on tophus volume. The total volumes of tophaceous deposition were quantified using automated volume assessment software. The 10-year cardiovascular risk using the Framingham Risk Score and metabolic syndrome based on the Third Adult Treatment Panel criteria were estimated. Fifty-five and 36 patients with positive and negative dual-energy computed tomography results, respectively, were assessed. Patients with positive dual-energy computed tomography results showed significantly higher systolic blood pressure, diastolic blood pressure, fasting glucose, and higher prevalence of chronic kidney disease, compared with those with negative dual-energy computed tomography results. The total tophus volumes were significantly correlated with the Framingham Risk Score, and the number of metabolic syndrome components (r = 0.22 and p = 0.036 and r = 0.373 and p < 0.001, respectively). The total tophus volume was one of the independent prognostic factors for the Framingham Risk Score in a multivariate analysis. This study showed the correlation of total tophus volumes with cardiovascular risk and metabolic syndrome-related comorbidities. A high urate burden could affect unfavorable cardiovascular profiles.

Three-dimensional visualization of the craniofacial patient: volume segmentation, data integration and animation.

PubMed

Enciso, R; Memon, A; Mah, J

2003-01-01

The research goal at the Craniofacial Virtual Reality Laboratory of the School of Dentistry in conjunction with the Integrated Media Systems Center, School of Engineering, University of Southern California, is to develop computer methods to accurately visualize patients in three dimensions using advanced imaging and data acquisition devices such as cone-beam computerized tomography (CT) and mandibular motion capture. Data from these devices were integrated for three-dimensional (3D) patient-specific visualization, modeling and animation. Generic methods are in development that can be used with common CT image format (DICOM), mesh format (STL) and motion data (3D position over time). This paper presents preliminary descriptive studies on: 1) segmentation of the lower and upper jaws with two types of CT data--(a) traditional whole head CT data and (b) the new dental Newtom CT; 2) manual integration of accurate 3D tooth crowns with the segmented lower jaw 3D model; 3) realistic patient-specific 3D animation of the lower jaw.

Refraction-based X-ray Computed Tomography for Biomedical Purpose Using Dark Field Imaging Method

NASA Astrophysics Data System (ADS)

Sunaguchi, Naoki; Yuasa, Tetsuya; Huo, Qingkai; Ichihara, Shu; Ando, Masami

We have proposed a tomographic x-ray imaging system using DFI (dark field imaging) optics along with a data-processing method to extract information on refraction from the measured intensities, and a reconstruction algorithm to reconstruct a refractive-index field from the projections generated from the extracted refraction information. The DFI imaging system consists of a tandem optical system of Bragg- and Laue-case crystals, a positioning device system for a sample, and two CCD (charge coupled device) cameras. Then, we developed a software code to simulate the data-acquisition, data-processing, and reconstruction methods to investigate the feasibility of the proposed methods. Finally, in order to demonstrate its efficacy, we imaged a sample with DCIS (ductal carcinoma in situ) excised from a breast cancer patient using a system constructed at the vertical wiggler beamline BL-14C in KEK-PF. Its CT images depicted a variety of fine histological structures, such as milk ducts, duct walls, secretions, adipose and fibrous tissue. They correlate well with histological sections.

Corrosion of Ti6Al4V pins produced by direct metal laser sintering

NASA Astrophysics Data System (ADS)

de Damborenea, J. J.; Arenas, M. A.; Larosa, Maria Aparecida; Jardini, André Luiz; de Carvalho Zavaglia, Cecília Amélia; Conde, A.

2017-01-01

Direct Metal Laser Sintering (DMLS) technique allows the manufacturing a wide variety of medical devices for any type of prosthetic surgery (HIP, dental, cranial, maxillofacial) as well as for internal fixation devices (K-Wires or Steinmann Pins). There are a large number of research studies on DMLS, including microstructural characterization, mechanical properties and those based on production quality assurance but the influence of porosity in the corrosion behavior of these materials not been sufficiently considered. In the present paper, surgical pins of Ti6Al4V have been produced by DMLS. After testing in a phosphate buffered saline solution, the surface of the titanium alloy appeared locally covered by a voluminous white oxide. This unexpected behavior was presumably due to the existence of internal defects in the pins as result of the manufacturing process. The importance of these defects-that might act as crevice nucleation sites- has been revealed by electrochemical techniques and confirmed by computed tomography.

Potential risk of alpha-glucosidase inhibitor administration in prostate cancer external radiotherapy by exceptional rectal gas production: a case report.

PubMed

Nishimura, Takuya; Yamazaki, Hideya; Iwama, Kazuki; Oota, Yoshitaka; Aibe, Norihiro; Nakamura, Satoaki; Yoshida, Ken; Okabe, Haruumi; Yamada, Kei

2014-05-05

Radiotherapy is a standard treatment for prostate cancer, and image-guided radiotherapy is increasingly being used to aid precision of dose delivery to targeted tissues. However, precision during radiotherapy cannot be maintained when unexpected intrafraction organ motion occurs. We report our experience of internal organ motion caused by persistent gas production in a patient taking an alpha-glucosidase inhibitor. A 68-year-old Japanese man with prostate cancer visited our institution for treatment with helical tomotherapy. He suffered from diabetes mellitus and took an alpha-glucosidase inhibitor. Routine treatment planning computed tomography showed a large volume of rectal gas; an enema was given to void the rectum. Subsequent treatment planning computed tomography again showed a large volume of gas. After exercise (walking) to remove the intestinal gas, a third scan was performed as a test scan without tight fixation, which showed a sufficiently empty rectum for planning. However, after only a few minutes, treatment planning computed tomography again showed extreme accumulation of gas. Therefore, we postponed treatment planning computed tomography and consulted his doctor to suspend the alpha-glucosidase inhibitor, which was the expected cause of his persistent gas. Four days after the alpha-glucosidase inhibitor regimen was suspended, we took a fourth treatment planning computed tomography and made a treatment plan without gas accumulation. Thereafter, the absence of rectal gas accumulation was confirmed using daily megavolt computed tomography before treatment, and the patient received 37 fractions of intensity-modified radiotherapy at 74 Gy without rectal gas complications. In this case study, the alpha-glucosidase inhibitor induced the accumulation of intestinal gas, which may have caused unexpected organ motion, untoward reactions, and insufficient doses to clinical targets. We suggest that patients who are taking an alpha-glucosidase inhibitor for diabetes should discontinue use of that particular medicine prior to beginning radiotherapy.

Comparison of Online 6 Degree-of-Freedom Image Registration of Varian TrueBeam Cone-Beam CT and BrainLab ExacTrac X-Ray for Intracranial Radiosurgery.

PubMed

Li, Jun; Shi, Wenyin; Andrews, David; Werner-Wasik, Maria; Lu, Bo; Yu, Yan; Dicker, Adam; Liu, Haisong

2017-06-01

The study was aimed to compare online 6 degree-of-freedom image registrations of TrueBeam cone-beam computed tomography and BrainLab ExacTrac X-ray imaging systems for intracranial radiosurgery. Phantom and patient studies were performed on a Varian TrueBeam STx linear accelerator (version 2.5), which is integrated with a BrainLab ExacTrac imaging system (version 6.1.1). The phantom study was based on a Rando head phantom and was designed to evaluate isocenter location dependence of the image registrations. Ten isocenters at various locations representing clinical treatment sites were selected in the phantom. Cone-beam computed tomography and ExacTrac X-ray images were taken when the phantom was located at each isocenter. The patient study included 34 patients. Cone-beam computed tomography and ExacTrac X-ray images were taken at each patient's treatment position. The 6 degree-of-freedom image registrations were performed on cone-beam computed tomography and ExacTrac, and residual errors calculated from cone-beam computed tomography and ExacTrac were compared. In the phantom study, the average residual error differences (absolute values) between cone-beam computed tomography and ExacTrac image registrations were 0.17 ± 0.11 mm, 0.36 ± 0.20 mm, and 0.25 ± 0.11 mm in the vertical, longitudinal, and lateral directions, respectively. The average residual error differences in the rotation, roll, and pitch were 0.34° ± 0.08°, 0.13° ± 0.09°, and 0.12° ± 0.10°, respectively. In the patient study, the average residual error differences in the vertical, longitudinal, and lateral directions were 0.20 ± 0.16 mm, 0.30 ± 0.18 mm, 0.21 ± 0.18 mm, respectively. The average residual error differences in the rotation, roll, and pitch were 0.40°± 0.16°, 0.17° ± 0.13°, and 0.20° ± 0.14°, respectively. Overall, the average residual error differences were <0.4 mm in the translational directions and <0.5° in the rotational directions. ExacTrac X-ray image registration is comparable to TrueBeam cone-beam computed tomography image registration in intracranial treatments.

Spine Trabecular Bone Score as an Indicator of Bone Microarchitecture at the Peripheral Skeleton in Kidney Transplant Recipients.

PubMed

Luckman, Matthew; Hans, Didier; Cortez, Natalia; Nishiyama, Kyle K; Agarawal, Sanchita; Zhang, Chengchen; Nikkel, Lucas; Iyer, Sapna; Fusaro, Maria; Guo, Edward X; McMahon, Donald J; Shane, Elizabeth; Nickolas, Thomas L

2017-04-03

Studies using high-resolution peripheral quantitative computed tomography showed progressive abnormalities in cortical and trabecular microarchitecture and biomechanical competence over the first year after kidney transplantation. However, high-resolution peripheral computed tomography is a research tool lacking wide availability. In contrast, the trabecular bone score is a novel and widely available tool that uses gray-scale variograms of the spine image from dual-energy x-ray absorptiometry to assess trabecular quality. There are no studies assessing whether trabecular bone score characterizes bone quality in kidney transplant recipients. Between 2009 and 2010, we conducted a study to assess changes in peripheral skeletal microarchitecture, measured by high-resolution peripheral computed tomography, during the first year after transplantation in 47 patients managed with early corticosteroid-withdrawal immunosuppression. All adult first-time transplant candidates were eligible. Patients underwent imaging with high-resolution peripheral computed tomography and dual-energy x-ray absorptiometry pretransplantation and 3, 6, and 12 months post-transplantation. We now test if, during the first year after transplantation, trabecular bone score assesses the evolution of bone microarchitecture and biomechanical competence as determined by high-resolution peripheral computed tomography. At baseline and follow-up, among the 72% and 78%, respectively, of patients having normal bone mineral density by dual-energy x-ray absorptiometry, 53% and 50%, respectively, were classified by trabecular bone score as having high fracture risk. At baseline, trabecular bone score correlated with spine, hip, and ultradistal radius bone mineral density by dual-energy x-ray absorptiometry and cortical area, density, thickness, and porosity; trabecular density, thickness, separation, and heterogeneity; and stiffness and failure load by high-resolution peripheral computed tomography. Longitudinally, each percentage increase in trabecular bone score was associated with increases in trabecular number (0.35%±1.4%); decreases in trabecular thickness (-0.45%±0.15%), separation (-0.40%±0.15%), and network heterogeneity (-0.48%±0.20%); and increases in failure load (0.22%±0.09%) by high-resolution peripheral computed tomography (all P <0.05). Trabecular bone score may be a useful method to assess and monitor bone quality and strength and classify fracture risk in kidney transplant recipients. Copyright © 2017 by the American Society of Nephrology.

Spine Trabecular Bone Score as an Indicator of Bone Microarchitecture at the Peripheral Skeleton in Kidney Transplant Recipients

PubMed Central

Luckman, Matthew; Hans, Didier; Cortez, Natalia; Nishiyama, Kyle K.; Agarawal, Sanchita; Zhang, Chengchen; Nikkel, Lucas; Iyer, Sapna; Fusaro, Maria; Guo, Edward X.; McMahon, Donald J.; Shane, Elizabeth

2017-01-01

Background and objectives Studies using high-resolution peripheral quantitative computed tomography showed progressive abnormalities in cortical and trabecular microarchitecture and biomechanical competence over the first year after kidney transplantation. However, high-resolution peripheral computed tomography is a research tool lacking wide availability. In contrast, the trabecular bone score is a novel and widely available tool that uses gray-scale variograms of the spine image from dual-energy x-ray absorptiometry to assess trabecular quality. There are no studies assessing whether trabecular bone score characterizes bone quality in kidney transplant recipients. Design, settings, participants, & measurements Between 2009 and 2010, we conducted a study to assess changes in peripheral skeletal microarchitecture, measured by high-resolution peripheral computed tomography, during the first year after transplantation in 47 patients managed with early corticosteroid–withdrawal immunosuppression. All adult first-time transplant candidates were eligible. Patients underwent imaging with high-resolution peripheral computed tomography and dual-energy x-ray absorptiometry pretransplantation and 3, 6, and 12 months post-transplantation. We now test if, during the first year after transplantation, trabecular bone score assesses the evolution of bone microarchitecture and biomechanical competence as determined by high-resolution peripheral computed tomography. Results At baseline and follow-up, among the 72% and 78%, respectively, of patients having normal bone mineral density by dual-energy x-ray absorptiometry, 53% and 50%, respectively, were classified by trabecular bone score as having high fracture risk. At baseline, trabecular bone score correlated with spine, hip, and ultradistal radius bone mineral density by dual-energy x-ray absorptiometry and cortical area, density, thickness, and porosity; trabecular density, thickness, separation, and heterogeneity; and stiffness and failure load by high-resolution peripheral computed tomography. Longitudinally, each percentage increase in trabecular bone score was associated with increases in trabecular number (0.35%±1.4%); decreases in trabecular thickness (−0.45%±0.15%), separation (−0.40%±0.15%), and network heterogeneity (−0.48%±0.20%); and increases in failure load (0.22%±0.09%) by high-resolution peripheral computed tomography (all P<0.05). Conclusions Trabecular bone score may be a useful method to assess and monitor bone quality and strength and classify fracture risk in kidney transplant recipients. PMID:28348031

X-ray Micro-Tomography of Ablative Heat Shield Materials

NASA Technical Reports Server (NTRS)

Panerai, Francesco; Ferguson, Joseph; Borner, Arnaud; Mansour, Nagi N.; Barnard, Harold S.; MacDowell, Alastair A.; Parkinson, Dilworth Y.

2016-01-01

X-ray micro-tomography is a non-destructive characterization technique that allows imaging of materials structures with voxel sizes in the micrometer range. This level of resolution makes the technique very attractive for imaging porous ablators used in hypersonic entry systems. Besides providing a high fidelity description of the material architecture, micro-tomography enables computations of bulk material properties and simulations of micro-scale phenomena. This presentation provides an overview of a collaborative effort between NASA Ames Research Center and Lawrence Berkeley National Laboratory, aimed at developing micro-tomography experiments and simulations for porous ablative materials. Measurements are carried using x-rays from the Advanced Light Source at Berkeley Lab on different classes of ablative materials used in NASA entry systems. Challenges, strengths and limitations of the technique for imaging materials such as lightweight carbon-phenolic systems and woven textiles are discussed. Computational tools developed to perform numerical simulations based on micro-tomography are described. These enable computations of material properties such as permeability, thermal and radiative conductivity, tortuosity and other parameters that are used in ablator response models. Finally, we present the design of environmental cells that enable imaging materials under simulated operational conditions, such as high temperature, mechanical loads and oxidizing atmospheres.Keywords: Micro-tomography, Porous media, Ablation

Radiology diagnostic devices under emergency electric power at disaster base hospitals during the acute phase of the Great East Japan Earthquake: results of a survey of all disaster base hospitals in Miyagi Prefecture.

PubMed

Maezawa, Shota; Kudo, Daisuke; Furukawa, Hajime; Nakagawa, Atsuhiro; Yamanouchi, Satoshi; Matsumura, Takashi; Egawa, Shinichi; Tominaga, Teiji; Kushimoto, Shigeki

2014-12-01

This study aimed to clarify the management of emergency electric power and the operation of radiology diagnostic devices after the Great East Japan Earthquake. Timing of electricity restoration, actual emergency electric power generation, and whether radiology diagnostic devices were operational and the reason if not were investigated through a questionnaire submitted to all 14 disaster base hospitals in Miyagi Prefecture in February and March 2013. Commercial electricity supply resumed within 3 days after the earthquake at 13 of 14 hospitals. Actual emergency electric power generation was lower than pre-disaster estimates at most of the hospitals. Only 4 of 11 hospitals were able to generate 60% of the power normally consumed. Under emergency electric power, conventional X-ray and computed tomography (CT) scanners worked in 9 of 14 (64%) and 8 of 14 (57%) hospitals, respectively. The main reason conventional X-ray and CT scanners did not operate was that hospitals had not planned to use these devices under emergency electric power. Only 2 of the 14 hospitals had a pre-disaster plan to allocate emergency electric power, and all devices operated at these 2 hospitals. Pre-disaster plans to allocate emergency electric power are required for disaster base hospitals to effectively operate radiology diagnostic devices after a disaster. (Disaster Med Public Health Preparedness. 2014;8:548-552).

Compliant Buckled Foam Actuators and Application in Patient-Specific Direct Cardiac Compression.

PubMed

Mac Murray, Benjamin C; Futran, Chaim C; Lee, Jeanne; O'Brien, Kevin W; Amiri Moghadam, Amir A; Mosadegh, Bobak; Silberstein, Meredith N; Min, James K; Shepherd, Robert F

2018-02-01

We introduce the use of buckled foam for soft pneumatic actuators. A moderate amount of residual compressive strain within elastomer foam increases the applied force ∼1.4 × or stroke ∼2 × compared with actuators without residual strain. The origin of these improved characteristics is explained analytically. These actuators are applied in a direct cardiac compression (DCC) device design, a type of implanted mechanical circulatory support that avoids direct blood contact, mitigating risks of clot formation and stroke. This article describes a first step toward a pneumatically powered, patient-specific DCC design by employing elastomer foam as the mechanism for cardiac compression. To form the device, a mold of a patient's heart was obtained by 3D printing a digitized X-ray computed tomography or magnetic resonance imaging scan into a solid model. From this model, a soft, robotic foam DCC device was molded. The DCC device is compliant and uses compressed air to inflate foam chambers that in turn apply compression to the exterior of a heart. The device is demonstrated on a porcine heart and is capable of assisting heart pumping at physiologically relevant durations (∼200 ms for systole and ∼400 ms for diastole) and stroke volumes (∼70 mL). Although further development is necessary to produce a fully implantable device, the material and processing insights presented here are essential to the implementation of a foam-based, patient-specific DCC design.

Validation of 3D multimodality roadmapping in interventional neuroradiology

NASA Astrophysics Data System (ADS)

Ruijters, Daniel; Homan, Robert; Mielekamp, Peter; van de Haar, Peter; Babic, Drazenko

2011-08-01

Three-dimensional multimodality roadmapping is entering clinical routine utilization for neuro-vascular treatment. Its purpose is to navigate intra-arterial and intra-venous endovascular devices through complex vascular anatomy by fusing pre-operative computed tomography (CT) or magnetic resonance (MR) with the live fluoroscopy image. The fused image presents the real-time position of the intra-vascular devices together with the patient's 3D vascular morphology and its soft-tissue context. This paper investigates the effectiveness, accuracy, robustness and computation times of the described methods in order to assess their suitability for the intended clinical purpose: accurate interventional navigation. The mutual information-based 3D-3D registration proved to be of sub-voxel accuracy and yielded an average registration error of 0.515 mm and the live machine-based 2D-3D registration delivered an average error of less than 0.2 mm. The capture range of the image-based 3D-3D registration was investigated to characterize its robustness, and yielded an extent of 35 mm and 25° for >80% of the datasets for registration of 3D rotational angiography (3DRA) with CT, and 15 mm and 20° for >80% of the datasets for registration of 3DRA with MR data. The image-based 3D-3D registration could be computed within 8 s, while applying the machine-based 2D-3D registration only took 1.5 µs, which makes them very suitable for interventional use.

21 CFR 892.1310 - Nuclear tomography system.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Nuclear tomography system. 892.1310 Section 892.1310 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... other planes. This generic type of devices may include signal analysis and display equipment, patient...

21 CFR 892.1310 - Nuclear tomography system.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Nuclear tomography system. 892.1310 Section 892.1310 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... other planes. This generic type of devices may include signal analysis and display equipment, patient...

21 CFR 892.1310 - Nuclear tomography system.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Nuclear tomography system. 892.1310 Section 892.1310 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... other planes. This generic type of devices may include signal analysis and display equipment, patient...

21 CFR 892.1310 - Nuclear tomography system.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Nuclear tomography system. 892.1310 Section 892.1310 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... other planes. This generic type of devices may include signal analysis and display equipment, patient...

21 CFR 892.1310 - Nuclear tomography system.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Nuclear tomography system. 892.1310 Section 892.1310 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... other planes. This generic type of devices may include signal analysis and display equipment, patient...

Abernethy malformation with portal vein aneurysm in a child

PubMed Central

Chandrashekhara, Sheragaru H.; Bhalla, Ashu Seith; Gupta, Arun Kumar; Vikash, C. S.; Kabra, Susheel Kumar

2011-01-01

Abernethy malformation is an extremely rare anomaly of the splanchnic venous system. We describe multidetector computed tomography findings of an incidentally detected Abernethy malformation with portal vein aneurysm in a two-and-half-year old child. The computed tomography scan was performed for the evaluation of respiratory distress, poor growth, and loss of appetite. PMID:21430844

Transmission of Hepatitis C Virus during Computed Tomography Scanning with Contrast

PubMed Central

Rius, Cristina; Caylà, Joan A.

2008-01-01

Six cases of acute hepatitis C related to computed tomography scanning with contrast were identified in 3 hospitals. A patient with chronic hepatitis C had been subjected to the same procedure immediately before each patient who developed acute infection. Viral molecular analysis showed identity between isolates from cases with acute and chronic hepatitis C. PMID:18258135

An Integrated Teaching Method of Gross Anatomy and Computed Tomography Radiology

ERIC Educational Resources Information Center

Murakami, Tohru; Tajika, Yuki; Ueno, Hitoshi; Awata, Sachiko; Hirasawa, Satoshi; Sugimoto, Maki; Kominato, Yoshihiko; Tsushima, Yoshito; Endo, Keigo; Yorifuji, Hiroshi

2014-01-01

It is essential for medical students to learn and comprehend human anatomy in three dimensions (3D). With this in mind, a new system was designed in order to integrate anatomical dissections with diagnostic computed tomography (CT) radiology. Cadavers were scanned by CT scanners, and students then consulted the postmortem CT images during cadaver…

Computed tomography findings of gaseous necrosis in epithelial ovarian cancer: a report of three cases.

PubMed

Cronin, Paul; Crosse, Barbara; Lane, Geoff; Spencer, John A

2002-01-01

Necrosis in pathologic specimens of ovarian cancer is well documented; however, computed tomography (CT) evidence of gaseous necrosis in the absence of fistulation with bowel has not yet been described. We report three cases of ovarian adenocarcinoma that on CT showed evidence of gross gaseous necrosis, mimicking a pelvic abscess.

Non-medical Uses of Computed Tomography (CT) and Nuclear Magnetic Resonance

Science.gov Websites

Finding Aids dropdown arrow Site Map A-Z Index Menu Synopsis Non-medical Uses of Computed Tomography (CT materials characterizations, and to provide non-destructive evaluations for discovering flaws in parts presence and facilitate the recovery/extraction of oil, water, coal, and/or gas; and to provide non

Utilization of high resolution computed tomography to visualize the three dimensional structure and function of plant vasculature

USDA-ARS?s Scientific Manuscript database

High resolution x-ray computed tomography (HRCT) is a non-destructive diagnostic imaging technique with sub-micron resolution capability that is now being used to evaluate the structure and function of plant xylem network in three dimensions (3D). HRCT imaging is based on the same principles as medi...

Tangential scanning of hardwood logs: developing an industrial computer tomography scanner

Treesearch

Nand K. Gupta; Daniel L. Schmoldt; Bruce Isaacson

1999-01-01

It is generally believed that noninvasive scanning of hardwood logs such as computer tomography (CT) scanning prior to initial breakdown will greatly improve the processing of logs into lumber. This belief, however, has not translated into rapid development and widespread installation of industrial CT scanners for log processing. The roadblock has been more operational...

An Easily Assembled Laboratory Exercise in Computed Tomography

ERIC Educational Resources Information Center

Mylott, Elliot; Klepetka, Ryan; Dunlap, Justin C.; Widenhorn, Ralf

2011-01-01

In this paper, we present a laboratory activity in computed tomography (CT) primarily composed of a photogate and a rotary motion sensor that can be assembled quickly and partially automates data collection and analysis. We use an enclosure made with a light filter that is largely opaque in the visible spectrum but mostly transparent to the near…

Documentation of the ISA Micro Computed Tomography System

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

Brown, William D.; Smith, Jerel A.

2013-12-18

This document is intended to provide information on the ISA Micro Computed Tomography (MicroCT) system that will be installed in Yavne, Israel. X-ray source, detector, and motion control hardware are specified as well as specimen platforms, containers, and reference material types. Most of the details on the system are derived from Reference 1 and 2.