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Sample records for mri implants causing

  1. SU-E-J-257: Image Artifacts Caused by Implanted Calypso Beacons in MRI Studies

    SciTech Connect

    Amro, H; Chetty, I; Gordon, J; Wen, N

    2014-06-01

    Purpose: The presence of Calypso Beacon-transponders in patients can cause artifacts during MRI imaging studies. This could be a problem for post-treatment follow up of cancer patients using MRI studies to evaluate metastasis and for functional imaging studies.This work assesses (1) the volume immediately surrounding the transponders that will not be visualized by the MRI due to the beacons, and (2) the dependence of the non-visualized volume on beacon orientation, and scanning techniques. Methods: Two phantoms were used in this study (1) water filled box, (2) and a 2300 cc block of pork meat. Calypso beacons were implanted in the phantoms both in parallel and perpendicular orientations with respect to the MR scanner magnetic field. MR image series of the phantom were obtained with on a 1.0T high field open MR-SIM with multiple pulse sequences, for example, T1-weighted fast field echo and T2-weighted turbo spin echo. Results: On average, a no-signal region with 2 cm radius and 3 cm length was measured. Image artifacts are more significant when beacons are placed parallel to scanner magnetic field; the no-signal area around the beacon was about 0.5 cm larger in orthogonal orientation. The no-signal region surrounding the beacons slightly varies in dimension for the different pulse sequences. Conclusion: The use of Calypso beacons can prohibit the use of MRI studies in post-treatment assessments, especially in the immediate region surrounding the implanted beacon. A characterization of the MR scanner by identifying the no-signal regions due to implanted beacons is essential. This may render the use of Calypso beacons useful for some cases and give the treating physician a chance to identify those patients prior to beacon implantation.

  2. Implantable medical devices MRI safe.

    PubMed

    Dal Molin, Renzo; Hecker, Bertrand

    2013-01-01

    Pacemakers, ICDs, neurostimulators like deep brain stimulator electrodes, spiral cord stimulators, insulin pumps, cochlear implants, retinal implants, hearing aids, electro cardio gram (ECG) leads, or devices in interventional MRI such as vascular guide wires or catheters are affected by MRI magnetic and electromagnetic fields. Design of MRI Safe medical devices requires computer modeling, bench testing, phantom testing, and animal studies. Implanted medical devices can be MRI unsafe, MRI conditional or MRI safe (see glossary). In the following paragraphs we will investigate how to design implanted medical devices MRI safe. PMID:23739365

  3. Tracking cells implanted into cynomolgus monkeys (Macaca fascicularis) using MRI

    PubMed Central

    Ito-Fujishiro, Yasuyo; Koie, Hiroshi; Shibata, Hiroaki; Okabayashi, Sachi; Katakai, Yuko; Ohno, Chieko; Kanayama, Kiichi; Yasutomi, Yasuhiro; Ageyama, Naohide

    2016-01-01

    Regenerative therapy with stem cell transplantation is used to treat various diseases such as coronary syndrome and Buerger’s disease. For instance, stem-cell transplantation into the infarcted myocardium is an innovative and promising strategy for treating heart failure due to ischemic heart disease. Basic studies using small animals have shown that transplanted cells improve blood flow in the infarcted region. Magnetic resonance imaging (MRI) can noninvasively identify and track transplanted cells labeled with superparamagnetic iron oxide (SPIO). Although clinical regenerative therapies have been clinically applied to patients, the fate of implanted cells remains unknown. In addition, follow-up studies have shown that some adverse events can occur after recovery. Therefore, the present study evaluated the ability of MRI using a 3T scanner to track implanted peripheral blood mononuclear cells labeled with SPIO on days 0 and 7 after intramuscular (i.m.) and intravenous (i.v.) injection into a cynomolgus monkey. Labeled cells were visualized at the liver and triceps surae muscle on MR images using T1- and T2-weighted sequences and histologically localized by Prussian blue staining. The transplanted cells were tracked without abnormal clinical manifestations throughout this study. Hence, MRI of cynomolgus monkey transplanted SPIO-labeled cells is a safe and efficient method of tracking labeled cells that could help to determine the mechanisms involved in regenerative therapy. PMID:27062993

  4. Tracking cells implanted into cynomolgus monkeys (Macaca fascicularis) using MRI.

    PubMed

    Ito-Fujishiro, Yasuyo; Koie, Hiroshi; Shibata, Hiroaki; Okabayashi, Sachi; Katakai, Yuko; Ohno, Chieko; Kanayama, Kiichi; Yasutomi, Yasuhiro; Ageyama, Naohide

    2016-07-29

    Regenerative therapy with stem cell transplantation is used to treat various diseases such as coronary syndrome and Buerger's disease. For instance, stem-cell transplantation into the infarcted myocardium is an innovative and promising strategy for treating heart failure due to ischemic heart disease. Basic studies using small animals have shown that transplanted cells improve blood flow in the infarcted region. Magnetic resonance imaging (MRI) can noninvasively identify and track transplanted cells labeled with superparamagnetic iron oxide (SPIO). Although clinical regenerative therapies have been clinically applied to patients, the fate of implanted cells remains unknown. In addition, follow-up studies have shown that some adverse events can occur after recovery. Therefore, the present study evaluated the ability of MRI using a 3T scanner to track implanted peripheral blood mononuclear cells labeled with SPIO on days 0 and 7 after intramuscular (i.m.) and intravenous (i.v.) injection into a cynomolgus monkey. Labeled cells were visualized at the liver and triceps surae muscle on MR images using T1- and T2-weighted sequences and histologically localized by Prussian blue staining. The transplanted cells were tracked without abnormal clinical manifestations throughout this study. Hence, MRI of cynomolgus monkey transplanted SPIO-labeled cells is a safe and efficient method of tracking labeled cells that could help to determine the mechanisms involved in regenerative therapy. PMID:27062993

  5. Osseointegrated implant fracture: causes and treatment.

    PubMed

    Gealh, Walter Cristiano; Mazzo, Valéria; Barbi, Francisco; Camarini, Edevaldo Tadeu

    2011-08-01

    Despite its high success rate, therapy with osseointegrated dental implants is not free of complications. Among the problems that may occur is fracture of implants, which, albeit a rare phenomenon, may lead to unpleasant clinical outcomes for the patient, as well as for the clinician. Thus, it is paramount to know the factors related to the biological processes involved in maintenance of osseointegration and biomechanics applied to dental implants to prevent such complications, as well as treatment options available to deal with the problem. Therefore, the objectives of this work were to investigate the literature to identify causative factors that may lead to fracture of dental implants and to discuss available procedures. PMID:20553152

  6. Convex optimization of MRI exposure for mitigation of RF-heating from active medical implants.

    PubMed

    Córcoles, Juan; Zastrow, Earl; Kuster, Niels

    2015-09-21

    Local RF-heating of elongated medical implants during magnetic resonance imaging (MRI) may pose a significant health risk to patients. The actual patient risk depends on various parameters including RF magnetic field strength and frequency, MR coil design, patient's anatomy, posture, and imaging position, implant location, RF coupling efficiency of the implant, and the bio-physiological responses associated with the induced local heating. We present three constrained convex optimization strategies that incorporate the implant's RF-heating characteristics, for the reduction of local heating of medical implants during MRI. The study emphasizes the complementary performances of the different formulations. The analysis demonstrates that RF-induced heating of elongated metallic medical implants can be carefully controlled and balanced against MRI quality. A reduction of heating of up to 25 dB can be achieved at the cost of reduced uniformity in the magnitude of the B(1)(+) field of less than 5%. The current formulations incorporate a priori knowledge of clinically-specific parameters, which is assumed to be available. Before these techniques can be applied practically in the broader clinical context, further investigations are needed to determine whether reduced access to a priori knowledge regarding, e.g. the patient's anatomy, implant routing, RF-transmitter, and RF-implant coupling, can be accepted within reasonable levels of uncertainty. PMID:26350025

  7. Silicone Breast Implants: A Rare Cause of Pleural Effusion

    PubMed Central

    Shaik, Imam H.; Gandrapu, Bindu; Flores, David; Matta, Jyoti; Syed, Amer K.

    2015-01-01

    Pleural effusions are one of the rarest complications reported in patients with silicone gel filled breast implants. The silicone implants have potential to provoke chronic inflammation of pleura and subsequent pulmonary complications such as pleural effusion. Herein, we report a 44-year-old female who presented with left sided pleural effusion, six weeks after a silicone breast implantation surgery. The most common infectious, inflammatory, and malignant causes of pleural effusion were excluded with pleural fluid cytology and cultures. With recurrent effusion in the setting of recent surgery, the chemical reaction to silicone breast implants was sought and exploration was performed which revealed foreign body reaction (FBR) to silicone material. The symptoms dramatically improved after the explantation. PMID:26693375

  8. Convex optimization of MRI exposure for mitigation of RF-heating from active medical implants

    NASA Astrophysics Data System (ADS)

    Córcoles, Juan; Zastrow, Earl; Kuster, Niels

    2015-09-01

    Local RF-heating of elongated medical implants during magnetic resonance imaging (MRI) may pose a significant health risk to patients. The actual patient risk depends on various parameters including RF magnetic field strength and frequency, MR coil design, patient’s anatomy, posture, and imaging position, implant location, RF coupling efficiency of the implant, and the bio-physiological responses associated with the induced local heating. We present three constrained convex optimization strategies that incorporate the implant’s RF-heating characteristics, for the reduction of local heating of medical implants during MRI. The study emphasizes the complementary performances of the different formulations. The analysis demonstrates that RF-induced heating of elongated metallic medical implants can be carefully controlled and balanced against MRI quality. A reduction of heating of up to 25 dB can be achieved at the cost of reduced uniformity in the magnitude of the B1+ field of less than 5%. The current formulations incorporate a priori knowledge of clinically-specific parameters, which is assumed to be available. Before these techniques can be applied practically in the broader clinical context, further investigations are needed to determine whether reduced access to a priori knowledge regarding, e.g. the patient’s anatomy, implant routing, RF-transmitter, and RF-implant coupling, can be accepted within reasonable levels of uncertainty.

  9. MRI evaluation prior to Transcatheter Aortic Valve Implantation (TAVI): When to acquire and how to interpret.

    PubMed

    Chaturvedi, Abhishek; Hobbs, Susan K; Ling, Fred S; Chaturvedi, Apeksha; Knight, Peter

    2016-04-01

    Transcatheter Aortic Valve Implantation (TAVI) is increasingly being used in patients with severe aortic stenosis who are not candidates for surgery. ECG-gated CT angiography (CTA) plays an important role in the preoperative planning for these devices. As the number of patients undergoing these procedures increases, a subset of patients is being recognized who have contraindications to iodinated contrast medium, either due to a prior severe allergic type reaction or poor renal function. Another subgroup of patients with low flow and low gradient aortic stenosis is being recognized that are usually assessed for severity of aortic stenosis by stress echocardiography. There are contraindications to stress echocardiography and some of these patients may not be able to undergo this test. Non-contrast MRI can be a useful emerging modality for evaluating these patients. In this article, we discuss the emerging indications of non-contrast MRI in preoperative assessment for TAVI and describe the commonly used MRI sequences. A comparison of the most important measurements obtained for TAVI assessment on CTA and MRI from same subjects is included. Teaching Points • MRI can be used for preoperative assessment of aortic annulus. • MRI is an alternate to CTA when iodinated contrast is contraindicated. • Measurements obtained by non-contrast MRI are similar to contrast enhanced CTA. • MRI can be used to assess severity of aortic stenosis. PMID:26911969

  10. An implanted 8-channel array coil for high-resolution macaque MRI at 3T

    PubMed Central

    Janssens, T.; Keil, B.; Farivar, R.; McNab, J.A.; Polimeni, J. R.; Gerits, A.; Arsenault, J.T.; Wald, L. L.; Vanduffel, W.

    2012-01-01

    An 8-channel receive coil array was constructed and implanted adjacent to the skull in a male rhesus monkey in order to improve the sensitivity of (functional) brain imaging. The permanent implant was part of an acrylic headpost assembly and only the coil element loop wires were implanted. The tuning, matching, and preamplifier circuitry was connected via a removable external assembly. Signal-to-noise ratio (SNR) and noise amplification for parallel imaging were compared to a single-, 4-, and 8-channel external receive-only coil routinely used for macaque fMRI. In vivo measurements showed significantly improved SNR within the brain for the implanted versus the external coils. Within a region-of-interest covering the cerebral cortex, we observed a 5.4-, 3.6-fold, and 3.4-fold increase in SNR compared to the external single-, 4-, and 8-channel coil, respectively. In the center of the brain, the implanted array maintained a 2.4×, 2.5×, and 2.1× higher SNR, respectively compared to the external coils. The array performance was evaluated for anatomical, diffusion tensor and functional brain imaging. This study suggests that a stable implanted phased-array coil can be used in macaque MRI to substantially increase the spatial resolution for anatomical, diffusion tensor, and functional imaging. PMID:22609793

  11. MRI compatibility and visibility assessment of implantable medical devices.

    PubMed

    Schueler, B A; Parrish, T B; Lin, J C; Hammer, B E; Pangrle, B J; Ritenour, E R; Kucharczyk, J; Truwit, C L

    1999-04-01

    We have developed a protocol to evaluate the magnetic resonance (MR) compatibility of implantable medical devices. The testing protocol consists of the evaluation of magnetic field-induced movement, electric current, heating, image distortion, and device operation. In addition, current induction is evaluated with a finite element analysis simulation technique that models the effect of radiofrequency fields on each device. The protocol has been applied to several implantable infusion pumps and neurostimulators with associated attachments. Experiments were performed using a 1.5-T whole-body MR system with parameters selected to approximate the intended clinical and worst case configuration. The devices exhibited moderate magnetic field-induced deflection and torque but had significant image artifacts. No heating was detected for any of the devices. Pump operation was halted in the magnetic field, but resumed after removed. Exposure to the magnetic field activated some of the neurostimulators. PMID:10232520

  12. Feasibility of Structural and Functional MRI Acquisition with Unpowered Implants in Argus II Retinal Prosthesis Patients: A Case Study

    PubMed Central

    Cunningham, Samantha I.; Shi, Yonggang; Weiland, James D.; Falabella, Paulo; Olmos de Koo, Lisa C.; Zacks, David N.; Tjan, Bosco S.

    2015-01-01

    Purpose Magnetic resonance imaging (MRI) can measure the effects of vision loss and recovery on brain function and structure. In this case study, we sought to determine the feasibility of acquiring anatomical and functional MRI data in recipients of the Argus II epiretinal prosthesis system. Methods Following successful implantation with the Argus II device, two retinitis pigmentosa (RP) patients completed MRI scans with their implant unpowered to measure primary visual cortex (V1) functional responses to a tactile task, whole-brain morphometry, V1 cortical thickness, and diffusion properties of the optic tract and optic radiation. Measurements in the subjects with the Argus II implant were compared to measurements obtained previously from RP patients and sighted individuals. Results The presence of the Argus II implant resulted in artifacts that were localized around the patient's implanted eye and did not extend into cortical regions or white matter tracts associated with the visual system. Structural data on V1 cortical thickness and the retinofugal tract obtained from the two Argus II subjects fell within the ranges of sighted and RP groups. When compared to the RP and sighted subjects, Argus II patients' tactile-evoked cross-modal functional MRI (fMRI) blood oxygen level-dependent (BOLD) responses in V1 also fell within the range of either sighted or RP groups, apparently depending on time since implantation. Conclusions This study demonstrates that successful acquisition and quantification of structural and functional MR images are feasible in the presence of the inactive implant and provides preliminary information on functional changes in the brain that may follow sight restoration treatments. Transitional Relevance Successful MRI and fMRI acquisition in Argus II recipients demonstrates feasibility of using MRI to study the effect of retinal prosthesis use on brain structure and function. PMID:26693097

  13. Tracking the Fate of Stem Cell Implants with Fluorine-19 MRI

    PubMed Central

    Gaudet, Jeffrey M.; Ribot, Emeline J.; Chen, Yuhua; Gilbert, Kyle M.; Foster, Paula J.

    2015-01-01

    Background In this study we used cellular magnetic resonance imaging (MRI) to detect mesenchymal stem cells (MSC) labeled with a Fluorine-19 (19F) agent. 19F-MRI offers unambiguous detection and in vivo quantification of labeled cells. Methods We investigated two common stem cell transplant mouse models: an immune competent, syngeneic transplant model and an immune compromised, xenograft transplant model. 19F labelled stem cells were implanted intramuscularly into the hindlimb of healthy mice. The transplant was then monitored for up to 17 days using 19F-MRI, after which the tissue was excised for fluorescence microscopy and immunohistochemisty. Results Immediately following transplantation, 19F-MRI quantification correlated very well with the expected cell number in both models. The 19F signal decreased over time in both models, with a more rapid decrease in the syngeneic model. By endpoint, only 2/7 syngeneic mice had any detectable 19F signal. In the xenograft model, all mice had detectable signal at endpoint. Fluorescence microscopy and immunohistochemistry were used to show that the 19F signal was related to the presence of bystander labeled macrophages, and not original MSC. Conclusions Our results show that 19F-MRI is an excellent tool for verifying the delivery of therapeutic cells early after transplantation. However, in certain circumstances the transfer of cellular label to other bystander cells may confuse interpretation of the long-term fate of the transplanted cells. PMID:25767871

  14. Successful treatment of a large implant periapical lesion that caused paraesthesia and perimandibular abscess

    PubMed Central

    Jafarian, Mohammad; Rayati, Farshid; Najafi, Elnaz

    2016-01-01

    Successful treatment of a large implant periapical lesion (IPL) that caused paraesthesia and perimandibular abscess. IPL is a pathologic phenomenon that rarely involves implants. This event first described in 1992 with an incidence rate of 0.26-9.9% and the origin is not well known. The most likely suggested causes are presence of preexisting bone pathology, contamination of implant surface, bone overheating during implant surgery, vascular ischemia, excessive tightening of the implant, fenestration of the buccal plate and different implant surface designs. In the present case report, we describe relatively large periapical lesions involving several implants caused severe abscess accompanied by transient inferior alveolar nerve paraesthesia and its successful management. A brief review of the literature and a discussion of possible causes and different treatment plans are also included. PMID:27076835

  15. Successful treatment of a large implant periapical lesion that caused paraesthesia and perimandibular abscess.

    PubMed

    Jafarian, Mohammad; Rayati, Farshid; Najafi, Elnaz

    2016-01-01

    Successful treatment of a large implant periapical lesion (IPL) that caused paraesthesia and perimandibular abscess. IPL is a pathologic phenomenon that rarely involves implants. This event first described in 1992 with an incidence rate of 0.26-9.9% and the origin is not well known. The most likely suggested causes are presence of preexisting bone pathology, contamination of implant surface, bone overheating during implant surgery, vascular ischemia, excessive tightening of the implant, fenestration of the buccal plate and different implant surface designs. In the present case report, we describe relatively large periapical lesions involving several implants caused severe abscess accompanied by transient inferior alveolar nerve paraesthesia and its successful management. A brief review of the literature and a discussion of possible causes and different treatment plans are also included. PMID:27076835

  16. Inferior alveolar nerve injury in implant dentistry: diagnosis, causes, prevention, and management.

    PubMed

    Alhassani, Ahmed Ali; AlGhamdi, Ali Saad Thafeed

    2010-01-01

    Inferior alveolar nerve injury is one of the most serious complications in implant dentistry. This nerve injury can occur during local anesthesia, implant osteotomy, or implant placement. Proper understanding of anatomy, surgical procedures, and implant systems and proper treatment planning is the key to reducing such an unpleasant complication. This review discusses the causes of inferior alveolar nerve injury and its diagnosis, prevention, and management. PMID:20545547

  17. Positive Contrast MRI Techniques for Visualization of Iron-Loaded Hernia Mesh Implants in Patients

    PubMed Central

    Ciritsis, Alexander; Truhn, Daniel; Hansen, Nienke L.; Otto, Jens; Kuhl, Christiane K.; Kraemer, Nils A.

    2016-01-01

    Object In MRI, implants and devices can be delineated via susceptibility artefacts. To discriminate susceptibility voids from proton-free structures, different positive contrast techniques were implemented. The purpose of this study was to evaluate a pulse sequence-based positive contrast technique (PCSI) and a post-processing susceptibility gradient mapping algorithm (SGM) for visualization of iron loaded mesh implants in patients. Material and Methods Five patients with iron-loaded MR-visible inguinal hernia mesh implants were examined at 1.5 Tesla. A gradient echo sequence (GRE; parameters: TR: 8.3ms; TE: 4.3ms; NSA:2; FA:20°; FOV:350mm²) and a PCSI sequence (parameters: TR: 25ms; TE: 4.6ms; NSA:4; FA:20°; FOV:350mm²) with on-resonant proton suppression were performed. SGM maps were calculated using two algorithms. Image quality and mesh delineation were independently evaluated by three radiologists. Results On GRE, the iron-loaded meshes generated distinct susceptibility-induced signal voids. PCSI exhibited susceptibility differences including the meshes as hyperintense signals. SGM exhibited susceptibility differences with positive contrast. Visually, the different algorithms presented no significant differences. Overall, the diagnostic value was rated best in GRE whereas PCSI and SGM were barely “sufficient”. Conclusion Both “positive contrast” techniques depicted implanted meshes with hyperintense signal. SGM comes without additional acquisition time and can therefore be utilized in every patient. PMID:27192201

  18. Penile Implants among Prisoners—A Cause for Concern?

    PubMed Central

    Yap, Lorraine; Butler, Tony; Richters, Juliet; Malacova, Eva; Wand, Handan; Smith, Anthony M. A.; Grant, Luke; Richards, Alun; Donovan, Basil

    2013-01-01

    Background We report the prevalence of penile implants among prisoners and determine the independent predictors for having penile implants. Questions on penile implants were included in the Sexual Health and Attitudes of Australian Prisoners (SHAAP) survey following concerns raised by prison health staff that increasing numbers of prisoners reported having penile implants while in prison. Methods Computer-Assisted Telephone Interviewing (CATI) of a random sample of prisoners was carried out in 41 prisons in New South Wales and Queensland (Australia). Men were asked, “Have you ever inserted or implanted an object under the skin of your penis?” If they responded Yes: “Have you ever done so while you were in prison?” Univariate logistic regression and logistic regression were used to determine the factors associated with penile implants. Results A total of 2,018 male prisoners were surveyed, aged between 18 and 65 years, and 118 (5.8%) reported that they had inserted or implanted an object under the skin of their penis. Of these men, 87 (73%) had this done while they were in prison. In the multivariate analysis, a younger age, birth in an Asian country, and prior incarceration were all significantly associated with penile implants (p<0.001). Men with penile implants were also more likely to report being paid for sex (p<0.001), to have had body piercings (p<0.001) or tattoos in prison (p<0.001), and to have taken non-prescription drugs while in prison (p<0.05). Conclusions Penile implants appear to be fairly common among prisoners and are associated with risky sexual and drug use practices. As most of these penile implants are inserted in prison, these men are at risk of blood borne viruses and wound infection. Harm reduction and infection control strategies need to be developed to address this potential risk. PMID:23326383

  19. Lethal Hemorrhage Caused by Aortoenteric Fistula Following Endovascular Stent Implantation

    SciTech Connect

    Kahlke, Volker; Brossmann, Joachim; Klomp, Hans-Juergen

    2002-06-15

    A 55-year-old women developed an aortointestinal fistula between the bifurcation of the aorta and the distal ileum following implantation of multiple endovascular stents into both common iliac arteries for treatment of aortoiliac occlusive disease. Ten months before the acute onset of the gastrointestinal hemorrhage two balloon-expandable steel stents had been implanted into both common iliac arteries. Due to restenosis and recurrent intermittent claudication, three balloon-expandable covered stents were implanted 4 months later on reintervention. The patient presented with abdominal pain and melena, and fell into hemorrhagic shock with signs of upper gastrointestinal bleeding. After transfer to our hospital, she again developed hemorrhagic shock with massive upper and lower gastrointestinal bleeding and died during emergency laparotomy. The development of aortoenteric fistulas following endovascular surgery/stent implantation is very rare and has to be considered in cases of acute gastrointestinal hemorrhage.

  20. Peri-implant bony overgrowth as a cause of revision surgery in auditory osseointegrated implantation.

    PubMed

    Tompkins, Jared J; Petersen, Dana K; Sharbel, Daniel D; McKinnon, Brian J; MacDonald, C Bruce

    2016-07-01

    Implantation of auditory osseointegrated implants, also known as bone-anchored hearing systems (BAHS), represents a surgical option for select pediatric patients aged 5 years or older with hearing loss. Functional indications in this patient population include conductive or mixed hearing loss. Common complications of implantation include skin infections, chronic skin irritation, hypertrophic skin overgrowth, and loose abutments. In a case series of 15 pediatric patients, we discovered an unexpectedly high skin-related complication rate requiring surgical revision of 53%. During revision surgery, we discovered 5 patients who exhibited significant bony overgrowth at the abutment site, a complication infrequently noted in past literature. PMID:27260587

  1. SU-C-17A-02: Sirius MRI Markers for Prostate Post-Implant Assessment: MR Protocol Development

    SciTech Connect

    Lim, T; Wang, J; Kudchadker, R; Stafford, R; Bathala, T; Pugh, T; Ibbott, G; Frank, S

    2014-06-15

    Purpose: Currently, CT is used to visualize prostate brachytherapy sources, at the expense of accurate structure contouring. MRI is superior to CT for anatomical delineation, but the sources appear as voids on MRI images. Previously we have developed Sirius MRI markers (C4 Imaging) to replace spacers to assist source localization on MRI images. Here we develop an MRI pulse sequence protocol that enhances the signal of these markers to enable MRI-only post-implant prostate dosimetric analysis. Methods: To simulate a clinical scenario, a CIRS multi-modality prostate phantom was implanted with 66 markers and 86 sources. The implanted phantom was imaged on both 1.5T and 3.0T GE scanners under various conditions, different pulse sequences (2D fast spin echo [FSE], 3D balanced steadystate free precession [bSSFP] and 3D fast spoiled gradient echo [FSPGR]), as well as varying amount of padding to simulate various patient sizes and associated signal fall-off from the surface coil elements. Standard FSE sequences from the current clinical protocols were also evaluated. Marker visibility, marker size, intra-marker distance, total scan time and artifacts were evaluated for various combinations of echo time, repetition time, flip angle, number of excitations, bandwidth, slice thickness and spacing, fieldof- view, frequency/phase encoding steps and frequency direction. Results: We have developed a 3D FSPGR pulse sequence that enhances marker signal and ensures the integrity of the marker shape while maintaining reasonable scan time. For patients contraindicated for 3.0T, we have also developed a similar sequence for 1.5T scanners. Signal fall-off with distance from prostate to coil can be compensated mainly by decreasing bandwidth. The markers are not visible using standard FSE sequences. FSPGR sequences are more robust for consistent marker visualization as compared to bSSFP sequences. Conclusion: The developed MRI pulse sequence protocol for Sirius MRI markers assists source

  2. Technical complications of implant-causes and management: A comprehensive review

    PubMed Central

    Gupta, Swati; Gupta, Hemant; Tandan, Amrit

    2015-01-01

    Given the increasing popularity of dental implants, the number of failures due to late implant fracture is also expected to increase. Hence, the scope for prevention and management needs to be emphasized. The objective of this review article is to analyze the various causes of failure of dental implants due to implant fixture/abutment screw fractures and also to enumerate the management and the preventive options for these failures, thereby aiming to help the clinicians to properly plan the implant-supported prosthesis treatment by considering the important biomechanical aspects of this type of rehabilitation. The present review emphasizes the causes and management of technical complications and not the incidence of such complications. PMID:26668445

  3. Atrial Fibrosis Quantified Using Late Gadolinium Enhancement MRI is Associated With Sinus Node Dysfunction Requiring Pacemaker Implant

    PubMed Central

    Akoum, Nazem; Mcgann, Christopher; Vergara, Gaston; Badger, Troy; Ranjan, Ravi; Mahnkopf, Christian; Kholmovski, Eugene; Macleod, Rob; Marrouche, Nassir

    2015-01-01

    Introduction Sinus node dysfunction (SND) commonly manifests with atrial arrhythmias alternating with sinus pauses and sinus bradycardia. The underlying process is thought to be because of atrial fibrosis. We assessed the value of atrial fibrosis, quantified using Late Gadolinium Enhanced-MRI (LGE-MRI), in predicting significant SND requiring pacemaker implant. Methods Three hundred forty-four patients with atrial fibrillation (AF) presenting for catheter ablation underwent LGE-MRI. Left atrial (LA) fibrosis was quantified in all patients and right atrial (RA) fibrosis in 134 patients. All patients underwent catheter ablation with pulmonary vein isolation with posterior wall and septal debulking. Patients were followed prospectively for 329 ± 245 days. Ambulatory monitoring was instituted every 3 months. Symptomatic pauses and bradycardia were treated with pacemaker implantation per published guidelines. Results The average patient age was 65 ± 12 years. The average wall fibrosis was 16.7 ± 11.1% in the LA, and 5.3 ± 6.4% in the RA. RA fibrosis was correlated with LA fibrosis (R2 = 0.26; P < 0.01). Patients were divided into 4 stages of LA fibrosis (Utah I: <5%, Utah II: 5–20%, Utah III: 20–35%, Utah IV: >35%). Twenty-two patients (mean atrial fibrosis, 23.9%) required pacemaker implantation during follow-up. Univariate and multivariate analysis identified LA fibrosis stage (OR, 2.2) as a significant predictor for pacemaker implantation with an area under the curve of 0.704. Conclusions In patients with AF presenting for catheter ablation, LGE-MRI quantification of atrial fibrosis demonstrates preferential LA involvement. Significant atrial fibrosis is associated with clinically significant SND requiring pacemaker implantation. PMID:21806700

  4. Assessment of MRI issues at 3-Tesla for metallic surgical implants: findings applied to 61 additional skin closure staples and vessel ligation clips

    PubMed Central

    2012-01-01

    Purpose Metallic skin closure staples and vessel ligation clips should be tested at 3-Tesla to characterize MRI issues in order to ensure patient safety. Therefore, metallic surgical implants were assessed at 3-Tesla for magnetic field interactions, MRI-related heating, and artifacts. Methods A skin closure staple (Visistat Skin Stapler, staple, Polytetrafluoroethylene, PTFE, coated 316L/316LVM stainless steel; Teleflex Medical, Durham, NC) and a vessel ligation clip (Hemoclip Traditional, stainless steel; Teleflex Medical, Durham, NC) that represented the largest metallic sizes made from materials with the highest magnetic susceptibilities (i.e., based on material information) among 61 other surgical implants (52 metallic implants, 9 nonmetallic implants) underwent evaluation for magnetic field interactions, MRI-related heating, and artifacts using standardized techniques. MRI-related heating was assessed by placing each implant in a gelled-saline-filled phantom with MRI performed using a transmit/receive RF body coil at an MR system reported, whole body averaged SAR of 2.9-W/kg for 15-min. Artifacts were characterized using T1-weighted, SE and GRE pulse sequences. Results Each surgical implant showed minor magnetic field interactions (20- and 27-degrees, which is acceptable from a safety consideration). Heating was not substantial (highest temperature change, ≤ 1.6°C). Artifacts may create issues if the area of interest is in the same area or close to the respective surgical implant. Conclusions The results demonstrated that it would be acceptable for patients with these metallic surgical implants to undergo MRI at 3-Tesla or less. Because of the materials and dimensions of the surgical implants that underwent testing, these findings pertain to 61 additional similar implants. PMID:22230200

  5. Modified Wideband Three-Dimensional Late Gadolinium Enhancement MRI for Patients with Implantable Cardiac Devices

    PubMed Central

    Rashid, Shams; Rapacchi, Stanislas; Shivkumar, Kalyanam; Plotnik, Adam; Finn, J. Paul; Hu, Peng

    2015-01-01

    Purpose To study the effects of cardiac devices on three-dimensional (3D) late gadolinium enhancement (LGE) MRI and to develop a 3D LGE protocol for implantable cardioverter defibrillator (ICD) patients with reduced image artifacts. Theory and Methods The 3D LGE sequence was modified by implementing a wideband inversion pulse, which reduces hyperintensity artifacts, and by increasing bandwidth of the excitation pulse. The modified wideband 3D LGE sequence was tested in phantoms and evaluated in six volunteers and five patients with ICDs. Results Phantom and in vivo studies results demonstrated extended signal void and ripple artifacts in 3D LGE that were associated with ICDs. The reason for these artifacts was slab profile distortion and the subsequent aliasing in the slice-encoding direction. The modified wideband 3D LGE provided significantly reduced ripple artifacts than 3D LGE with wideband inversion only. Comparison of 3D and 2D LGE images demonstrated improved spatial resolution of the heart using 3D LGE. Conclusion Increased bandwidth of the inversion and excitation pulses can significantly reduce image artifacts associated with ICDs. Our modified wideband 3D LGE protocol can be readily used for imaging patients with ICDs given appropriate safety guidelines are followed. PMID:25772155

  6. A prospective audit of pacemaker function, implant lifetime, and cause of death in the patient.

    PubMed Central

    Suvarna, S K; Start, R D; Tayler, D I

    1999-01-01

    AIM: To audit prospectively the reasons for pacemaker implantation, the duration of the pacemaker use, the cause of death, and pacemaker function after removal from the patient. METHODS: Pacemakers were removed at necropsy, or from the bodies of patients awaiting cremation, in three hospitals over a three year period. The cause of death was taken from the results of the necropsy or from the certified cause of death. Demographic data, including the time of implant and reasons for implantation, were checked. The pacemakers were analysed in terms of battery status, program, and output under a standard 470 ohm load. RESULTS: 69 patients were studied. Average age at death was 78 and 80 years for men and women, respectively. The average duration since pacemaker implantation was 46 months. Eleven patients had necropsies, showing that three died from ischaemic heart disease, six from cardiomyopathy, one from an aortic aneurysm, and one from disseminated neoplasia. From the necropsy results and death certificates, the distribution of causes of death in the group as a whole were ischaemic heart disease (21), cardiomyopathy (8), cerebrovascular disease (11), neoplasia (11), chest infection/chronic obstructive airways disease (8), and other causes (10). In all cases the pacemaker box function was within normal limits. CONCLUSIONS: Neither primary nor secondary pacemaker dysfunction was found. The study highlights the impact of arrhythmias in cardiomyopathy, and raises questions about the true role of ischaemic heart disease in these pacemaker requiring patients. The relatively short gap between pacemaker implantation and death requires further study. Images PMID:10655989

  7. Ring-type ESD damage caused by electrostatic chuck of ion implanter

    NASA Astrophysics Data System (ADS)

    King, Mingchu; Hsu, Chun-Keng; Fu, Chiang; Huang, Hsin-Chie; Yang, Shih-Yi; Liu, Yuan-Lung; Hsu, Kuo-chin

    1999-04-01

    Electrostatic discharge (ESD) due to electrostatic chuck (ESC) during ion implantation was observed in our fab. This defect could burn out the inter-layer dielectric and jeopardize the circuit performance. the yield impact on 0.35 micrometers product could be 40 percent. The defect distributed around the wafer edge and has a ring-type map. This defect occurred right after ESD implantation. The fringe field of the electrostatic chuck is the key reason why ring-type electrostatic discharge damage happened right after ion implantation. Our experimental result also showed that the junction characterization and surface conductivity will influence the probability of ESD damage caused by electrostatic chuck of ion implanter.

  8. Multiple Stent Fractures After Everolimus-Eluting Stent Implantation Causing Acute Myocardial Infarction

    PubMed Central

    Ji, Eun Young; Park, Gyung-Min; Kim, Dae Won; Kim, Tae-Seok; Kim, Chan Joon; Cho, Jung Sun; Park, Mahn-Won; Her, Sung Ho

    2016-01-01

    Abstract Stent fracture is an uncommon complication of drug-eluting stent implantation, but it has a clinical significance because of its potential association with adverse cardiac events such as in-stent restenosis, target lesion revascularization, and stent thrombosis. Multiple stent fractures account for a small proportion, but they may lead to more serious complications. Newer generation drug-eluting stents are designed for improved safety and efficacy compared with early generation drug-eluting stents. Multiple stent fractures after newer generation drug-eluting stent implantation are a rare case. We report a case of 25-year-old male who presented with acute myocardial infarction caused by multiple stent fractures after everolimus-eluting stents implantation and was treated by balloon angioplasty. Physicians should be aware of the possibility of multiple stent fractures even after newer generation drug-eluting stent implantation. PMID:26871806

  9. Hepatic Sinusoidal Obstruction Syndrome Caused by Herbal Medicine: CT and MRI Features

    PubMed Central

    Zhou, Hua; Wang, Yi-Xiang J.; Lou, Hai-yan; Xu, Xiao-jun

    2014-01-01

    Objective To describe the CT and MRI features of hepatic sinusoidal obstruction syndrome (HSOS) caused by herbal medicine Gynura segetum. Materials and Methods The CT and MRI features of 16 consecutive Gynura segetum induced HSOS cases (12 men, 4 women) were analyzed. Eight patients had CT; three patients had MRI, and the remaining five patients had both CT and MRI examinations. Based on their clinical presentations and outcomes, the patients were classified into three categories: mild, moderate, and severe. The severity of the disease was also evaluated radiologically based on the abnormal hepatic patchy enhancement in post-contrast CT or MRI images. Results Ascites, patchy liver enhancement, and main right hepatic vein narrowing or occlusion were present in all 16 cases. Hepatomegaly and gallbladder wall thickening were present in 14 cases (87.5%, 14/16). Periportal high intensity on T2-weighted images was present in 6 cases (75%, 6/8). Normal liver parenchymal enhancement surrounding the main hepatic vein forming a clover-like sign was observed in 4 cases (25%, 4/16). The extent of patchy liver enhancement was statistically associated with clinical severity classification (kappa = 0.565). Conclusion Ascites, patchy liver enhancement, and the main hepatic veins narrowing were the most frequent signs of herbal medicine induced HSOS. The grade of abnormal patchy liver enhancement was associated with the clinical severity. PMID:24643319

  10. Costal bone abnormalities: an unusual cause of spontaneous bilateral breast implant deflation†.

    PubMed

    Brooker, Jack E; Gusenoff, Jeffrey A

    2014-01-01

    Augmentation mammoplasty is the most common aesthetic surgical procedure performed in the USA. Prosthetic failure is a major reason for surgical reintervention. A number of causes for this have been documented, but costal bone abnormalities leading to perforation of the prosthesis are very unusual. We present the case of a woman who experienced spontaneous deflation of both saline implants in close succession, and who was found to have sharp bony spicules on both sides of her chest. Pathology examination reported reactive changes, suggestive of heterotopic bone. Examination of the implants showed no defects besides small punctures on the back wall, which coincided with the position of the spicules of bone. There are a number of possible causes for these bony growths which we examine in turn. The chest wall should be examined in all cases where unexplained implant deflation has occurred. PMID:25535321

  11. Screw insertion in trabecular bone causes peri-implant bone damage.

    PubMed

    Steiner, Juri A; Ferguson, Stephen J; van Lenthe, G Harry

    2016-04-01

    Secure fracture fixation is still a major challenge in orthopedic surgery, especially in osteoporotic bone. While numerous studies have investigated the effect of implant loading on the peri-implant bone after screw insertion, less focus has been put on bone damage that may occur due to the screw insertion process itself. Therefore, the aim of this study was to localize and quantify peri-implant bone damage caused by screw insertion. We used non-invasive three-dimensional micro-computed tomography to scan twenty human femoral bone cores before and after screw insertion. After image registration of the pre- and post-insertion scans, changes in the bone micro-architecture were identified and quantified. This procedure was performed for screws with a small thread size of 0.3mm (STS, N=10) and large thread size of 0.6mm (LTS, N=10). Most bone damage occurred within a 0.3mm radial distance of the screws. Further bone damage was observed up to 0.6mm and 0.9mm radial distance from the screw, for the STS and LTS groups, respectively. While a similar amount of bone damage was found within a 0.3mm radial distance for the two screw groups, there was significantly more bone damage for the LTS group than the STS group in volumes of interest between 0.3-0.6mm and 0.6-0.9mm. In conclusion, this is the first study to localize and quantify peri-implant bone damage caused by screw insertion based on a non-invasive, three-dimensional, micro-CT imaging technique. We demonstrated that peri-implant bone damage already occurs during screw insertion. This should be taken into consideration to further improve primary implant stability, especially in low quality osteoporotic bone. We believe that this technique could be a promising method to assess more systematically the effect of peri-implant bone damage on primary implant stability. Furthermore, including peri-implant bone damage due to screw insertion into patient-specific in silico models of implant-bone systems could improve the

  12. Erroneous discharge of an implantable cardioverter defibrillator caused by an electric razor.

    PubMed

    Seifert, T; Block, M; Borggrefe, M; Breithardt, G

    1995-08-01

    We report an unusual case of the erroneous discharge of a third-generation multiprogrammable implantable cardioverter defibrillator in a 64-year-old patient with a history of recurrent ventricular tachycardias caused by electromagnetic interference while shaving with an electric razor. Electromagnetic interference was related to a defect in the electrode's insulation and could not be provoked in an intact electrode. PMID:7479183

  13. FUNCTIONAL BRAIN MAPPING AT 9.4T USING A NEW MRI COMPATIBLE ELECTRODE CHRONICALLY IMPLANTED IN RATS

    PubMed Central

    Dunn, Jeff F.; Tuor, Ursula I.; Kmech, Jonn; Young, Nicole A.; Henderson, Amy K.; Jackson, Jesse C.; Valentine, Pamela A.; Teskey, G. Campbell

    2009-01-01

    There is a need for acute and chronic stimulation of the brain within the MRI for studies of epilepsy, as well as of deep brain stimulation for movement and behavioral disorders. This paper describes the production and characteristics of carbon fiber based electrodes for acute and chronic stimulation in the brain. Increasing MRI field strengths are making it increasingly difficult to introduce foreign objects without a susceptibility artifact. This paper describes the production of, and the characteristics of carbon fiber based electrodes. These are biocompatible and can be implanted for chronic studies. We show the use of these electrodes at 9.4T for studying functional activation. Data are presented showing regional connectivity. Activation not only occurs near the electrode, but at sites distant and often contralateral to the electrode. In addition, there were sites showing strong negative activation to stimulation both with direct stimulation and during a kindling associated seizure. PMID:19097225

  14. Thymoma of the left thymic lobe with a contralateral small pleural implant successfully detected with diffusion-weighted MRI.

    PubMed

    Priola, Adriano Massimiliano; Priola, Sandro Massimo

    2015-01-01

    Thymoma is the most common primary neoplasm of the anterior mediastinum. At diagnosis, up to 40% of patients present with advanced disease. Because advanced thymomas receive neoadjuvant chemotherapy, diagnostic imaging is crucial to plan the correct treatment. For characterizing thymomas, CT is the first choice modality, whereas 18F-FDG/PET is reserved for questionable cases and MRI is not routinely employed. Hereby, we describe a case of thymoma with a single contralateral pleural implant in a 30-year-old woman. The small pleural thickening detected at CT was correctly interpreted as pleural seeding related to thymoma at diffusion-weighted (DW)-MRI after a negative 18F-FDG/PET scan, and was subsequently confirmed at surgery. Precise diagnosis and accurate preoperative staging are crucial in managing thymic epithelial tumours in order to design the appropriate treatment and improve prognosis. Indeed, when stage IVa for pleural seeding is diagnosed preoperatively, a multimodality approach including primary chemotherapy followed by surgery and postoperative radiotherapy/chemotherapy is recommended. This is the first report that used DW-MRI for the characterization of pleural seeding in thymoma and demonstrates that DW-MRI could be useful for the correct pre-operatory staging in thymoma patients, especially in cases with indeterminate pleural thickenings at CT, in order to define the correct management. PMID:25702681

  15. MRI

    MedlinePlus

    ... scan is an imaging test that uses powerful magnets and radio waves to create pictures of the ... in your eyes) Because the MRI contains strong magnets, metal objects are not allowed into the room ...

  16. The Safety of Using Body-Transmit MRI in Patients with Implanted Deep Brain Stimulation Devices

    PubMed Central

    Kahan, Joshua; Papadaki, Anastasia; White, Mark; Mancini, Laura; Yousry, Tarek; Zrinzo, Ludvic; Limousin, Patricia; Hariz, Marwan; Foltynie, Tom; Thornton, John

    2015-01-01

    Background Deep brain stimulation (DBS) is an established treatment for patients with movement disorders. Patients receiving chronic DBS provide a unique opportunity to explore the underlying mechanisms of DBS using functional MRI. It has been shown that the main safety concern with MRI in these patients is heating at the electrode tips – which can be minimised with strict adherence to a supervised acquisition protocol using a head-transmit/receive coil at 1.5T. MRI using the body-transmit coil with a multi-channel receive head coil has a number of potential advantages including an improved signal-to-noise ratio. Study outline We compared the safety of cranial MRI in an in vitro model of bilateral DBS using both head-transmit and body-transmit coils. We performed fibre-optic thermometry at a Medtronic ActivaPC device and Medtronic 3389 electrodes during turbo-spin echo (TSE) MRI using both coil arrangements at 1.5T and 3T, in addition to gradient-echo echo-planar fMRI exposure at 1.5T. Finally, we investigated the effect of transmit-coil choice on DBS stimulus delivery during MRI. Results Temperature increases were consistently largest at the electrode tips. Changing from head- to body-transmit coil significantly increased the electrode temperature elevation during TSE scans with scanner-reported head SAR 0.2W/kg from 0.45°C to 0.79°C (p<0.001) at 1.5T, and from 1.25°C to 1.44°C (p<0.001) at 3T. The position of the phantom relative to the body coil significantly impacted on electrode heating at 1.5T; however, the greatest heating observed in any position tested remained <1°C at this field strength. Conclusions We conclude that (1) with our specific hardware and SAR-limited protocol, body-transmit cranial MRI at 1.5T does not produce heating exceeding international guidelines, even in cases of poorly positioned patients, (2) cranial MRI at 3T can readily produce heating exceeding international guidelines, (3) patients with ActivaPC Medtronic systems are safe

  17. Causes of elevated intraocular pressure following implantation of phakic intraocular lenses for myopia.

    PubMed

    Almalki, Salem; Abubaker, Abdullah; Alsabaani, Nasser A; Edward, Deepak P

    2016-04-01

    The purpose of this study is to present the causes and visual acuity outcomes in patients with elevated intraocular pressure (IOP) following implantable collamer lens (ICL) implantation. A chart review identified patients who developed high IOP at any postoperative examination and a minimum follow-up period of 3 months after ICL implantation. Data are reported out to 6 months postoperatively. Outcome measures included causes of elevated IOP, best-corrected visual acuity (BCVA) at last visit, number of glaucoma medications, other interventions, and glaucomatous damage. Elevated IOP occurred in 58 (10.8 %) of 534 eyes that received ICL. The mean age was 28 ± 7.2 years. The preoperative IOP was 16.3 ± 1.2 mmHg. Elevated IOP most commonly occurred on the first postoperative day (23/58 (39.7 %) eyes) due to retained viscoelastic. This was followed by steroid response in 22/58 (37.9 %) eyes at 2-4 weeks postoperatively. IOP elevation in 6 (10.3 %) eyes was related to high ICL vault and pupillary block, and in 4 (6.9 %) eyes due to synechial angle closure. At last visit, BCVA was 20/40 or better in 56/58 (96.6 %) eyes, and 5/58 (8.6 %) eyes remained on glaucoma medications due to persistent steroid response (2 eyes), synechial angle closure glaucoma (1 eye), and other causes (2 eyes). One eye showed glaucomatous damage. Two eyes with high vault and elevated IOP underwent ICL explantation. There is a moderate risk of transiently developing elevated IOP after ICL implantation. Thorough removal of viscoelastic and use of anti-glaucoma medications during steroid use will reduce the majority of cases with postoperative IOP elevation. PMID:26265323

  18. Surgical repair of root perforation caused by an orthodontic miniscrew implant.

    PubMed

    Hwang, Yun-Chan; Hwang, Hyeon-Shik

    2011-03-01

    Root damage is a significant complication of orthodontic miniscrew implant placement. Although root damage is rare, its proper management should be clearly understood by practitioners. This article reports the iatrogenic root perforation of a mandibular lateral incisor caused by the placement of a miniscrew. Despite a large radiolucent area caused by chronic apical periodontitis, the perforation was successfully repaired by using a recently developed material, mineral trioxide aggregate. The treatment, clinical implications, and clinical guidelines for preventing root damage during miniscrew placement in orthodontic practice are discussed. PMID:21392697

  19. Implanted depleted uranium fragments cause soft tissue sarcomas in the muscles of rats.

    PubMed Central

    Hahn, Fletcher F; Guilmette, Raymond A; Hoover, Mark D

    2002-01-01

    In this study, we determined the carcinogenicity of depleted uranium (DU) metal fragments containing 0.75% titanium in muscle tissues of rats. The results have important implications for the medical management of Gulf War veterans who were wounded with DU fragments and who retain fragments in their soft tissues. We compared the tissue reactions in rats to the carcinogenicity of a tantalum metal (Ta), as a negative foreign-body control, and to a colloidal suspension of radioactive thorium dioxide ((232)Th), Thorotrast, as a positive radioactive control. DU was surgically implanted in the thigh muscles of male Wistar rats as four squares (2.5 x 2.5 x 1.5 mm or 5.0 x 5.0 x 1.5 mm) or four pellets (2.0 x 1.0 mm diameter) per rat. Ta was similarly implanted as four squares (5.0 x 5.0 x 1.1 mm) per rat. Thorotrast was injected at two sites in the thigh muscles of each rat. Control rats had only a surgical implantation procedure. Each treatment group included 50 rats. A connective tissue capsule formed around the metal implants, but not around the Thorotrast. Radiographs demonstrated corrosion of the DU implants shortly after implantation. At later times, rarifactions in the radiographic profiles correlated with proliferative tissue responses. After lifetime observation, the incidence of soft tissue sarcomas increased significantly around the 5.0 x 5.0 mm squares of DU and the positive control, Thorotrast. A slightly increased incidence occurred in rats implanted with the 2.5 x 2.5 mm DU squares and with 5.0 x 5.0 mm squares of Ta. No tumors were seen in rats with 2.0 x 1.0 mm diameter DU pellets or in the surgical controls. These results indicate that DU fragments of sufficient size cause localized proliferative reactions and soft tissue sarcomas that can be detected with radiography in the muscles of rats. PMID:11781165

  20. Implanted, inductively-coupled, radiofrequency coils fabricated on flexible polymeric material: Application to in vivo rat brain MRI at 7 T

    NASA Astrophysics Data System (ADS)

    Ginefri, J.-C.; Rubin, A.; Tatoulian, M.; Woytasik, M.; Boumezbeur, F.; Djemaï, B.; Poirier-Quinot, M.; Lethimonnier, F.; Darrasse, L.; Dufour-Gergam, E.

    2012-11-01

    Combined with high-field MRI scanners, small implanted coils allow for high resolution imaging with locally improved SNR, as compared to external coils. Small flexible implantable coils dedicated to in vivo MRI of the rat brain at 7 T were developed. Based on the Multi-turn Transmission Line Resonator design, they were fabricated with a Teflon substrate using copper micromolding process and a specific metal-polymer adhesion treatment. The implanted coils were made biocompatible by PolyDimethylSiloxane (PDMS) encapsulation. The use of low loss tangent material achieves low dielectric losses within the substrate and the use of the PDMS layer reduces the parasitic coupling with the surrounding media. An implanted coil was implemented in a 7 T MRI system using inductive coupling and a dedicated external pick-up coil for signal transmission. In vivo images of the rat brain acquired with in plane resolution of (150 μm)2 thanks to the implanted coil revealed high SNR near the coil, allowing for the visualization of fine cerebral structures.

  1. Implanted neural electrodes cause chronic, local inflammation that is correlated with local neurodegeneration

    NASA Astrophysics Data System (ADS)

    McConnell, George C.; Rees, Howard D.; Levey, Allan I.; Gutekunst, Claire-Anne; Gross, Robert E.; Bellamkonda, Ravi V.

    2009-10-01

    Prosthetic devices that are controlled by intracortical electrodes recording one's 'thoughts' are a reality today, and no longer merely in the realm of science fiction. However, widespread clinical use of implanted electrodes is hampered by a lack of reliability in chronic recordings, independent of the type of electrodes used. One major hypothesis has been that astroglial scar electrically impedes the electrodes. However, there is a temporal discrepancy between stabilization of scar's electrical properties and recording failure with recording failure lagging by 1 month. In this study, we test a possible explanation for this discrepancy: the hypothesis that chronic inflammation, due to the persistent presence of the electrode, causes a local neurodegenerative state in the immediate vicinity of the electrode. Through modulation of chronic inflammation via stab wound, electrode geometry and age-matched control, we found that after 16 weeks, animals with an increased level of chronic inflammation were associated with increased neuronal and dendritic, but not axonal, loss. We observed increased neuronal and dendritic loss 16 weeks after implantation compared to 8 weeks after implantation, suggesting that the local neurodegenerative state is progressive. After 16 weeks, we observed axonal pathology in the form of hyperphosphorylation of the protein tau in the immediate vicinity of the microelectrodes (as observed in Alzheimer's disease and other tauopathies). The results of this study suggest that a local, late onset neurodegenerative disease-like state surrounds the chronic electrodes and is a potential cause for chronic recording failure. These results also inform strategies to enhance our capability to attain reliable long-term recordings from implantable electrodes in the CNS.

  2. [Use of gold radionuclide markers implanted into the prostate for image-guided radiotherapy in prostate cancer: side effects caused by the marker implantation].

    PubMed

    Kliton, Jorgo; Ágoston, Péter; Szabó, Zoltán; Major, Tibor; Polgár, Csaba

    2014-09-01

    The purpose of the study was to introduce the use of the gold radiopaque markers implanted into the prostate for image-guided radiotherapy of prostate cancer patients and to present the side effects caused by the marker implantation. Between November 2011 and November 2013, three radiopaque, gold-plated markers (Best Medical International, Springfield, VA, USA, 1.0 mm x 3.0 mm) were implanted transperineally into the prostate of 60 patients under transrectal ultrasound guidance. Local anaesthesia was performed in all patients. A week after the procedure the patients filled in a questionnaire regarding the pain, dysuria, urinary frequency, nycturia, rectal bleeding, haematuria, haematospermia or fever symptoms caused by the implantation. The pain caused by the intervention was scored on a 1-10 scale, where 1 was a very weak and 10 was an unbearable pain. Ten days after the implantation a treatment planning CT was performed and subsequently patients started intensity-modulated radiation therapy (IMRT) within one week. During the treatments markers were used for daily verification and correction of patient's setup. No patients experienced fever or infection. Based on the questionnaires nobody experienced dysuria or rectal bleeding after implantation. Among the 60 patients studied, five (8 %) had haematospermia, nine (15 %) haematuria, which lasted in average of 3.4 and 1.8 days, respectively. The average pain score on 1-10 scale was 4.2 (range: 0-9). After the marker implantation 18 patients (30%) reported less, 10 patients (17%) more, and 27 patients (45%) equal amount of pain compared to biopsy. Five patients, who had a biopsy performed under general anaesthesia, did not answer this question. None of the patients needed analgesics after implantation. The gold marker implantation implemented for image-guided radiotherapy was well tolerated under a local anaesthesia. The complications were limited, rate and frequency of perioperative pain was comparable to the pain

  3. Visual fatigue caused by watching 3DTV: an fMRI study.

    PubMed

    Chen, Chunxiao; Wang, Jing; Li, Kun; Liu, Yuping; Chen, Xin

    2015-01-01

    The objective of this study is to observe the visual fatigue caused by watching 3DTV using the method of functional magnetic resonance imaging (fMRI). The data of fMRI during three kinds of visual stimulation tasks were obtained from twenty subjects. At first, blood-oxygen-level dependent (BOLD) signal changes during stimuli of checkerboard task were compared before and after one-hour watching 3D/2DTV, and subjective evaluation was conducted based on the questionnaire simultaneously. Then 3D and 2D images were used to stimulate healthy individuals to measure brain activities that correlated with stereoscopic vision. Finally, the relationship between front or back depth of field images and visual fatigue was investigated. The results reveal that the 3D group shows more significant differences of brain activities in BA8, BA17, BA18 and BA19 than the 2D group during the checkerboard stimulation. BA5, BA6, BA7 and BA8 were testified to have close relationship with stereoscopic perception via the 2D/3D images stimulation. Furthermore, the front depth of field image was proven to impose a more serious impact on visual fatigue than the back one. These conclusions are useful for healthy and reasonable 3DTV watching as well as properly designing of 3D scenes. PMID:25603496

  4. Implantable Cardioverter-Defibrillator Shock Caused by Uncommon Variety of Nonreentrant Atrioventricular Nodal Tachycardia.

    PubMed

    Singh, David K; Badhwar, Nitish

    2016-03-01

    This article reports a typical case of incessant double-fire tachycardia resulting in implantable cardioverter-defibrillator discharge caused by the device's misdiagnosis of ventricular tachycardia. At electrophysiology study, the presence of double-fire physiology was confirmed, and modification of the slow pathway resulted in elimination of repetitive double fires. Although this is an unusual entity, it is important to recognize, because it may be misdiagnosed as atrial fibrillation, resulting in inappropriate anticoagulation and/or antiarrhythmic therapy. Modification of the slow pathway and elimination of double-fire physiology can result in marked improvement in quality of life and reversal of tachycardia-mediated cardiomyopathy. PMID:26920170

  5. Electromagnetic Interference with Implantable Cardioverter Defibrillators Causing Inadvertent Shock: Case Report and Review of Current Literature

    PubMed Central

    Akhtar, Muhammad; Bhat, Tariq; Tantray, Mohmad; Lafferty, Chris; Faisal, Saiful; Teli, Sumaya; Bhat, Hilal; Raza, Muhammad; Khalid, Mariam; Biekht, Soad

    2014-01-01

    As the number of patients having implantable cardioverter defibrillator (ICD) devices is increasing, it is important for the physicians and patients to be aware of situations and conditions that can result in interference with normal functioning of these devices. There are multiple cases of malfunction of ICDs reported in literature and it may be of great significance to have an overview of these incidents for appropriate recognition and future prevention. Here we are reviewing the available literature as well as reporting an interesting case of electromagnetic interference (EMI) resulting from leak of current in pool water causing firing of ICD. PMID:25093004

  6. Review of the principal extra spinal pathologies causing sciatica and new MRI approaches

    PubMed Central

    Ailianou, A; Fitsiori, A; Syrogiannopoulou, A; Toso, S; Viallon, M; Merlini, L; Beaulieu, J Y; Vargas, M I

    2012-01-01

    In this paper we illustrate the principal extraspinal pathologies causing sciatica and new approaches for the study of structures such as the lumbosacral plexus (LSP). Visualisation of the LSP in its entirety is difficult with conventional two-dimensional MRI sequences owing to its oblique orientation. In our institution, we have found that the utilisation of three-dimensional short tau inversion-recovery sampling perfection with application-optimised contrasts using different flip angle evolutions sequence is helpful, allowing multiplanar and maximum intensity projection reconstructions in the coronal oblique plane and curvilinear reformats through the plexus. Diffusion tensor imaging enables the observation of microstructural changes and can be useful in surgical planning. The normal anatomy of the LSP, its different extraspinal pathologies and differential diagnoses are thoroughly presented. PMID:22374280

  7. A novel POMT2 mutation causes mild congenital muscular dystrophy with normal brain MRI

    PubMed Central

    MURAKAMI, Terumi; HAYASHI, Yukiko K.; OGAWA, Megumu; NOGUCHI, Satoru; CAMPBELL, Kevin P.; TOGAWA, Masami; INOUE, Takehiko; OKA, Akira; OHNO, Kousaku; NONAKA, Ikuya; NISHINO, Ichizo

    2009-01-01

    We report a patient harboring a novel homozygous mutation of c.604T>G (p.F202V) in POMT2. He showed delayed psychomotor development but acquired the ability to walk at the age of 3 years and 10 months. His brain MRI was normal. No ocular abnormalities were seen. Biopsied skeletal muscle revealed markedly decreased but still detectable glycosylated forms of alpha-dystroglycan (α-DG). Our results indicate that mutations in POMT2 can cause a wide spectrum of clinical phenotypes as observed in other genes associated with alpha-dystroglycanopathy. Presence of small amounts of partly glycosylated α-DG may have a role in reducing the clinical symptoms of alpha-dystroglycanopathy. PMID:18804929

  8. Safe use of MRI in people with cardiac implantable electronic devices.

    PubMed

    Lowe, Martin D; Plummer, Christopher J; Manisty, Charlotte H; Linker, Nicholas J

    2015-12-01

    MR scanning in patients with cardiac implantable electronic devices (CIEDs) was formerly felt to be contraindicated, but an increasing number of patients have an implanted MR conditional device, allowing them to safely undergo MR scanning, provided the manufacturer's guidance is adhered to. In addition, some patients with non-MR conditional devices may undergo MR scanning if no other imaging modality is deemed suitable and there is a clear clinical indication for scanning which outweighs the potential risk. The following guidance has been formulated by the British Heart Rhythm Society and endorsed by the British Cardiovascular Society and others. It describes protocols that should be followed for patients with CIEDs undergoing MR scanning. The recommendations, principles and conclusions are supported by the Royal College of Radiologists. PMID:26420818

  9. HAX1 Mutations causing SCN and Neurological Disease Lead to Microstructural Abnormalities Revealed by Quantitative MRI

    PubMed Central

    Boztug, Kaan; Ding, Xiao-Qi; Hartmann, Hans; Ziesenitz, Lena; Schäffer, Alejandro A.; Diestelhorst, Jana; Pfeifer, Dietmar; Appaswamy, Giridharan; Kehbel, Sonja; Simon, Thorsten; Jefri, Abdullah Al; Lanfermann, Heinrich; Klein, Christoph

    2011-01-01

    Biallelic mutations in the gene encoding HCLS-associated protein X-1 (HAX1) cause autosomal recessive severe congenital neutropenia. Some of these patients display neurological abnormalities including developmental delay, cognitive impairment and/or epilepsy. Recent genotype-phenotype studies have shown that mutations in HAX1 affecting transcripts A (NM_006118.3) and B (NM_001018837.1) cause the phenotype of SCN with neurological impairment, while mutations affecting isoform A but not B lead to SCN without neurological aberrations. In this study, we identified a consanguineous family with two patients suffering from SCN and neurological disease caused by a novel, homozygous genomic deletion including exons 4–7 of the HAX1 gene. Quantitative MRI analyses revealed general alterations in cerebral proton density in both of the patients, as well as in an additional unrelated patient with another HAX1 mutation (Arg86X) known to be associated with neurological manifestations. This study provides first in vivo evidence of general neurodegeneration associated with HAX1 deficiency in SCN patients. PMID:21108402

  10. Implantation-caused open volume defects in Ge after flash lamp annealing (FLA) probed by slow positron implantation spectroscopy (SPIS)

    NASA Astrophysics Data System (ADS)

    Anwand, W.; Skorupa, W.; Schumann, Th.; Posselt, M.; Schmidt, B.; Grötzschel, R.; Brauer, G.

    2008-10-01

    B + and P + ions were implanted into Ge wafers covered with a pre-amorphised surface layer of 150 nm. After this, flash lamp annealing (FLA) in Ar atmosphere was used as post-implantation heat treatment. Radiation with Xenon flash lamps, having a spectrum in the visible range of light and a pulse length of 3 ms or 20 ms, allowed an ultra-short heating up of the near surface region. In this way, a modification of the structure of the as-implanted amorphous Ge layer was possible. Depth profiles of defects, especially those of the vacancy-type, were investigated by slow positron implantation spectroscopy (SPIS) before and after FLA. It was found that the remaining vacancy-type defect structure depends on the parameters of the process of heat treatment, and that these defects could not be completely removed by FLA. Results are compared with such from SRIM 2006 calculations (stopping and range of ions in matter) and Rutherford backscattering spectrometry (RBS).

  11. Histrelin Implant

    MedlinePlus

    ... bone growth and development of sexual characteristics) in girls usually between 2 and 8 years of age ... MRI scans (radiology techniques designed to show the images of body structures) to find the implant when ...

  12. Sleeping with the fishes: electromagnetic interference causing an inappropriate implantable cardioverter defibrillator shock

    PubMed Central

    Knight, Hui Min; Cakebread, Holly Elizabeth; Gajendragadkar, Parag Ravindra; Duehmke, Rudolf Martin

    2014-01-01

    A 60-year-old man with a cardiac defibrillator implanted due to previous ventricular fibrillation arrest and ischaemic cardiomyopathy received a shock while cleaning his fish pond. At the time, his immersed arm was close to a submersed water pump, but the patient was asymptomatic. As a result of the shock he lost consciousness, but collapsed backwards, away from the pond. Interrogation of the device revealed a high-frequency artefact that was sensed by the device and triggered a shock. Device parameters were otherwise normal. Subsequently, the submersed water pump was found to be the source of an external alternating current leak and was identified as the likely cause of the inappropriate shock due to electromagnetic interference (EMI). Awareness of potential sources of EMI along with evaluation of data with a detailed clinical history is warranted in all cases. PMID:24879728

  13. Re-implantation of a degloving amputation of distal index finger caused by fireworks: a case report and literature review.

    PubMed

    Zhang, Q; Cao, X C

    2013-07-01

    Amputations associated with fireworks are customarily treated by stump revision resulting in permanent disability. In this case report, we present an eight-year old boy who suffered an amputation of his right distal index finger at the level of the epiphyseal disk with degloving injury of the amputated finger caused by fireworks. Successful re-implantation was achieved. Two-year follow-up revealed fair cosmesis and acceptable functional and aesthetic recovery though the free distal phalanx had been absorbed completely. Re-implantation of a degloving amputation finger caused by fireworks is possible and can provide good distal soft tissue coverage and recovery of sensory and motor functions. PMID:24756749

  14. Effect of age on survival and causes of death after primary prevention implantable cardioverter-defibrillator implantation.

    PubMed

    Fauchier, Laurent; Marijon, Eloi; Defaye, Pascal; Piot, Olivier; Sadoul, Nicolas; Perier, Marie-Cecile; Gras, Daniel; Klug, Didier; Algalarrondo, Vincent; Bordachar, Pierre; Deharo, Jean-Claude; Leclercq, Christophe; Babuty, Dominique; Boveda, Serge

    2015-05-15

    The benefit of implantable cardioverter-defibrillators (ICDs) remains controversial in elderly patients and may be attenuated by a greater risk of nonarrhythmic death. We examined the effect of age on outcomes after prophylactic ICD implantation. All patients with coronary artery disease or dilated cardiomyopathy implanted with an ICD for primary prevention of sudden cardiac death in 12 French medical centers were included in a retrospective observational study. The 5,534 ICD recipients were divided according to age: 18 to 59 years (n = 2,139), 60 to 74 years (n = 2,693), and ≥75 years (n = 702). Greater prevalences of coronary artery disease and atrial fibrillation at the time of implant were observed with increasing age (both p <0.0001). During a mean follow-up of 3.1 ± 2.0 years, the annual mortality rate increased with age: 3.1% per year for age 18 to 59 years, 5.7% per year for age 60 to 74 years, and 7.5% per year for age ≥75 years (p <0.001). Older age was independently associated with a greater risk of death (adjusted odds ratio 1.43, 95% confidence interval 1.14 to 1.80 for age 60 to 74 years; and adjusted odds ratio 1.65, 95% confidence interval 1.22 to 2.22 for age >75 years). Proportions of cardiac deaths (55.2%, 57.6%, and 57.0%, p = 0.84), including ICD-unresponsive sudden death (9.9%, 6.0%, and 10.6%, p = 0.08), and rates of appropriate ICD therapies were similar in the 3 age groups. Older age was independently associated with a higher rate of early complications and a lower rate of inappropriate therapies. In conclusion, older patients exhibited higher global mortality after ICD implantation for primary prevention, whereas rates of sudden deaths and of appropriate device therapies were similar across age groups. PMID:25784518

  15. False-positive Extra-Mammary Findings in Breast MRI: Another Cause for Concern.

    PubMed

    Padia, Shilpa A; Freyvogel, Mary; Dietz, Jill; Valente, Stephanie; O'Rourke, Colin; Grobmyer, Stephen R

    2016-01-01

    Breast magnetic resonance imaging (MRI) has been repeatedly shown to have a high false-positive rate for additional findings in the breast resulting in additional breast imaging and biopsies. We hypothesize that breast MRI is also associated with a high rate of false-positive findings outside of the breast requiring additional evaluation, interventions, and delays in treatment. We performed a retrospective review of all breast MRIs performed on breast cancer patients in 2010 at a single institution. MRI reports were analyzed for extra-mammary findings. The timing and yield of the additional procedures was also analyzed. Three hundred and twenty-seven breast cancer patients (average age = 53.53 ± 11.08 years) had a breast MRI. Incidental, extra-mammary findings were reported in 35/327 patients (10.7%) with a total of 38 incidental findings. The extra-mammary findings were located in the liver (n = 21, 60.0%), thoracic cavity (n = 12, 34.3%), kidneys (n = 1, 2.9%), musculoskeletal system (n = 3, 8.6%), and neck (n = 1, 2.9%). Eighteen of the 35 patients (51.4%) received additional radiographic imaging, 3 (8.6%) received additional laboratory testing, 2 (5.7%) received additional physician referrals and 2 (5.7%) received a biopsy of the finding. The average time to additional procedures in these patients was 14.5 days. None of the incidental, extra-mammary findings were associated with breast cancer or other malignancy. Breast MRI was associated with a high rate (10.7%) of extra-mammary findings, which led to costly additional imaging studies, referrals, and tests. These findings were not associated with breast cancer or other malignancies. Extra-mammary findings highlight an unrecognized adverse consequence of breast MRI. PMID:26511429

  16. Migration of an automatic implantable cardioverter-defibrillator patch causing massive hemothorax.

    PubMed Central

    Quigley, R L; Hamer, M E; Swiryn, S

    1996-01-01

    The automatic implantable cardioverter-defibrillator is composed of shocking electrodes (patches or coils), sensing electrodes, and a generator implanted in the abdominal wall. A number of complications with defibrillators have been reported, including migration of the various components. We describe a patient in whom one of the patches, originally sutured extrapericardially, migrated in the right hemithorax and eroded into the ipsilateral lung. The resultant massive hemothorax necessitated urgent thoracotomy, patch removal, and hematoma evacuation. A hybrid implantable cardioverter-defibrillator system was created as a replacement to minimize surgery while protecting the patient from sudden death. Images PMID:8680276

  17. Preliminary investigation of a biological augmentation of rotator cuff repairs using a collagen implant: a 2-year MRI follow-up

    PubMed Central

    Bokor, Desmond John; Sonnabend, David; Deady, Luke; Cass, Ben; Young, Allan; Van Kampen, Craig; Arnoczky, Steven

    2015-01-01

    Summary Background the inability to restore the normal tendon footprint and limit strains on the repair site are thought to contribute to re-tearing following rotator cuff repair. The purpose of this study was to use a collagen implant to augment rotator cuff repairs through the restoration of the native tendon footprint and the induction of new tissue to decrease overall tendon strain. Methods repairs of full-thickness rotator cuff lesions in 9 adult patients were augmented with a novel collagen implant placed over the bursal surface of the repair. Tendon thickness and footprint anatomy were evaluated using MRI at 3, 6, 12, and 24 months. Clinical results were assessed using standard outcome metrics. Mean follow-up for all patients was 25.8 months. Results the implant induced significant new tissue formation in all patients by 3 months. This tissue matured over time and became indistinguishable from the underlying tendon. At 24 months all repairs remained intact and normal footprint anatomy of the tendon was restored in all patients. All clinical scores improved significantly over time. Conclusion the ability of a collagen implant to induce new host tissue formation and restore the normal footprint anatomy may represent a significant advancement in the biological augmentation and ultimate durability of rotator cuff repairs. PMID:26605186

  18. Experimental Evaluation of SAR around an Implanted Cardiac Pacemaker Caused by Mobile Radio Terminal

    NASA Astrophysics Data System (ADS)

    Endo, Yuta; Saito, Kazuyuki; Watanabe, Soichi; Takahashi, Masaharu; Ito, Koichi

    Although the effect of electromagnetic interference on an implanted cardiac pacemaker due to a nearby mobile phone has been investigated, there have been few studies on the enhancement of the specific absorption rate (SAR) around an implanted cardiac pacemaker due to a nearby mobile phone. In this study, the SAR distribution around a pacemaker model embedded in a parallelepiped torso phantom when a mobile phone was nearby was numerically calculated and experimentally measured. The results of both investigations showed a characteristic SAR distribution. The system presented can be used to estimate the effects of electromagnetic interference on implanted electric circuits and thus could lead to the development of guidelines for the safe use of mobile radio terminals near people with medical implants.

  19. iPad2® Use in Patients With Implantable Cardioverter Defibrillators Causes Electromagnetic Interference: The EMIT Study

    PubMed Central

    Kozik, Teri M.; Chien, Gianna; Connolly, Therese F.; Grewal, Gurinder S.; Liang, David; Chien, Walter

    2014-01-01

    Background Over 140 million iPads® have been sold worldwide. The iPad2®, with magnets embedded in its frame and Smart Cover and 3G cellular data capability, can potentially cause electromagnetic interference in implantable cardioverter defibrillators. This can lead to potentially life‐threatening situations in patients. The goal of this study was to determine whether the iPad2® can cause electromagnetic interference in patients with implantable cardioverter defibrillators. Methods and Results Twenty‐seven patients with implantable cardioverter defibrillators were studied. The iPad2® was held at reading distance and placed directly over the device with cellular data capability activated and deactivated. The manufacturers/models of devices and the patients' body mass index were noted. The presence of electromagnetic interference was detected by using a programmer supplied by each manufacturer. Magnet mode with suspension of anti‐tachycardia therapy was triggered in 9 (33%) patients. All occurred when the iPad2® was placed directly over the device. The cellular data status did not cause interference and no noise or oversensing was noted. There was no significant difference between the mean body mass index of the groups with or without interference. Conclusions The iPad2® can trigger magnet mode in implantable cardioverter defibrillators when laid directly over the device. This is potentially dangerous if patients should develop life‐threatening arrhythmias at the same time. As new electronic products that use magnets are produced, the potential risk to patients with implantable defibrillators needs to be addressed. PMID:24721802

  20. Adenomyosis is a potential cause of recurrent implantation failure during IVF treatment.

    PubMed

    Tremellen, Kelton; Russell, Peter

    2011-06-01

    Four women, who previously had undergone multiple unsuccessful in vitro fertilisation (IVF) cycles because of failure of implantation of good quality embryos, were identified as having coexisting uterine adenomyosis. Endometrial biopsies showed that adenomyosis was associated with a prominent aggregation of macrophages within the superficial endometrial glands, potentially interfering with embryo implantation. The inactivation of adenomyosis by an ultra-long pituitary downregulation regime promptly resulted in successful pregnancy for all women in this case series. PMID:21631453

  1. A gender based analysis of predictors of all cause death after transcatheter aortic valve implantation.

    PubMed

    Conrotto, Federico; D'Ascenzo, Fabrizio; Salizzoni, Stefano; Presbitero, Patrizia; Agostoni, Pierfrancesco; Tamburino, Corrado; Tarantini, Giuseppe; Bedogni, Francesco; Nijhoff, Freek; Gasparetto, Valeria; Napodano, Massimo; Ferrante, Giuseppe; Rossi, Marco Luciano; Stella, Pieter; Brambilla, Nedy; Barbanti, Marco; Giordana, Francesca; Grasso, Costanza; Biondi Zoccai, Giuseppe; Moretti, Claudio; D'Amico, Maurizio; Rinaldi, Mauro; Gaita, Fiorenzo; Marra, Sebastiano

    2014-10-15

    The impact of gender-related pathophysiologic features of severe aortic stenosis on transcatheter aortic valve implantation (TAVI) outcomes remains to be determined, as does the consistency of predictors of mortality between the genders. All consecutive patients who underwent TAVI at 6 institutions were enrolled in this study and stratified according to gender. Midterm all-cause mortality was the primary end point, with events at 30 days and at midterm as secondary end points. All events were adjudicated according to Valve Academic Research Consortium definitions. Eight hundred thirty-six patients were enrolled, 464 (55.5%) of whom were female. At midterm follow-up (median 365 days, interquartile range 100 to 516) women had similar rates of all-cause mortality compared with men (18.1% vs 22.6%, p = 0.11) and similar incidence of myocardial infarction and cerebrovascular accident. Gender did not affect mortality also on multivariate analysis. Among clinical and procedural features, glomerular filtration rate <30 ml/min/1.73 m(2) (hazard ratio [HR] 2.55, 95% confidence interval [CI] 1.36 to 4.79) and systolic pulmonary arterial pressure >50 mm Hg (HR 2.26, 95% CI 1.26 to 4.02) independently predicted mortality in women, while insulin-treated diabetes (HR 3.45, 95% CI 1.47 to 8.09), previous stroke (HR 3.42, 95% CI 1.43 to 8.18), and an ejection fraction <30% (HR 3.82, 95% CI 1.41 to 10.37) were related to mortality in men. Postprocedural aortic regurgitation was independently related to midterm mortality in the 2 groups (HR 11.19, 95% CI 3.3 to 37.9). In conclusion, women and men had the same life expectancy after TAVI, but different predictors of adverse events stratified by gender were demonstrated. These findings underline the importance of a gender-tailored clinical risk assessment in TAVI patients. PMID:25159239

  2. FEF-microstimulation causes task-dependent modulation of occipital fMRI activity.

    PubMed

    Premereur, Elsie; Janssen, Peter; Vanduffel, Wim

    2013-02-15

    Electrical microstimulation of FEF (FEF-EM) modulates neuronal activity in area V4 (Moore and Armstrong, 2003) and elicits functional magnetic resonance imaging (fMRI) activations in visual cortex in a bottom-up dependent manner (Ekstrom et al., 2008). Here we test the hypothesis that FEF-EM-induced modulations of fMRI activity are also function of task demands, which would suggest top-down dependent gating of FEF signals in early visual cortex. We scanned two monkeys performing a visually guided saccade task; a passive fixation task with a very similar visual display; and a passive fixation task without peripheral dots. We found increased effects of FEF-EM on fMRI-activity in visual cortex during saccades compared to fixation, indicating that the FEF-EM induced modulation is task-dependent. Finally, the effect of FEF-EM is mainly present in voxels which were less activated by visual stimuli in the absence of electrical stimulation. Our results show that the FEF-EM-induced pattern of activation in early visual cortex is topographically specific and more pronounced during increased task demands. These results fit with models suggesting that FEF is an important source modulating activity in early sensory cortex and that these influences can be enhanced by coincident bottom-up or top-down signals. PMID:23186918

  3. SU-E-J-214: MR Protocol Development to Visualize Sirius MRI Markers in Prostate Brachytherapy Patients for MR-Based Post-Implant Dosimetry

    SciTech Connect

    Lim, T; Wang, J; Frank, S; Stafford, R; Bruno, T; Bathala, T; Mahmood, U; Pugh, T; Ibbott, G; Kudchadker, R

    2015-06-15

    Purpose: The current CT-based post-implant dosimetry allows precise seed localization but limited anatomical delineation. Switching to MR-based post-implant dosimetry is confounded by imprecise seed localization. One approach is to place positive-contrast markers (Sirius) adjacent to the negative-contrast seeds. This patient study aims to assess the utility of a 3D fast spoiled gradient-recalled echo (FSPGR) sequence to visualize Sirius markers for post-implant dosimetry. Methods: MRI images were acquired in prostate implant patients (n=10) on Day 0 (day-of-implant) and Day 30. The post-implant MR protocol consisted of 3D T2-weighted fast-spin-echo (FSE), T2-weighted 2D-FSE (axial) and T1-weighted 2D-FSE (axial/sagittal/coronal). We incorporated a 3D-FSPGR sequence into the post-implant MR protocol to visualize the Sirius markers. Patients were scanned with different number-of-excitations (6, 8, 10), field-of-view (10cm, 14cm, 18cm), slice thickness (1mm, 0.8mm), flip angle (14 degrees, 20 degrees), bandwidth (122.070 Hz/pixel, 325.508 Hz/pixel, 390.625 Hz/pixel), phase encoding steps (160, 192, 224, 256), frequency-encoding direction (right/left, anterior/posterior), echo-time type (minimum-full, out-of-phase), field strength (1.5T, 3T), contrast (with, without), scanner vendor (Siemens, GE), coil (endorectal-coil only, endorectal-and-torso-coil, torsocoil only), endorectal-coil filling (30cc, 50cc) and endorectal-coil filling type (air, perfluorocarbon [PFC]). For post-implant dosimetric evaluation with greater anatomical detail, 3D-FSE images were fused with 3D-FSPGR images. For comparison with CT-based post-implant dosimetry, CT images were fused with 3D-FSPGR images. Results: The 3D-FSPGR sequence facilitated visualization of markers in patients. Marker visualization helped distinguish signal voids as seeds versus needle tracks for more definitive MR-based post-implant dosimetry. On the CT-MR fused images, the distance between the seed on CT to MR images was 3

  4. A Novel Operative Procedure for Pelvic Organ Prolapse Utilizing a MRI-Visible Mesh Implant: Safety and Outcome of Modified Laparoscopic Bilateral Sacropexy

    PubMed Central

    Meyberg-Solomayer, Gabriele; Radosa, Julia; Bader, Werner; Schneider, Guenther; Solomayer, Erich

    2015-01-01

    Introduction. Sacropexy is a generally applied treatment of prolapse, yet there are known possible complications of it. An essential need exists for better alloplastic materials. Methods. Between April 2013 and June 2014, we performed a modified laparoscopic bilateral sacropexy (MLBS) in 10 patients using a MRI-visible PVDF mesh implant. Selected patients had prolapse POP-Q stages II-III and concomitant OAB. We studied surgery-related morbidity, anatomical and functional outcome, and mesh-visibility in MRI. Mean follow-up was 7.4 months. Results. Concomitant colporrhaphy was conducted in 1/10 patients. Anatomical success was defined as POP-Q stage 0-I. Apical success rate was 100% and remained stable. A recurrent cystocele was seen in 1/10 patients during follow-up without need for intervention. Out of 6 (6/10) patients with preoperative SUI, 5/6 were healed and 1/6 persisted. De-novo SUI was seen in 1/10 patients. Complications requiring a relaparoscopy were seen in 2/10 patients. 8/10 patients with OAB were relieved postoperatively. The first in-human magnetic resonance visualization of a prolapse mesh implant was performed and showed good quality of visualization. Conclusion. MLBS is a feasible and safe procedure with favorable anatomical and functional outcome and good concomitant healing rates of SUI and OAB. Prospective data and larger samples are required. PMID:25961042

  5. Measurement of lattice damage caused by ion-implantation doping of semiconductors.

    NASA Technical Reports Server (NTRS)

    Hunsperger, R. G.; Wolf, E. D.; Shifrin, G. A.; Marsh, O. J.; Jamba, D. M.

    1971-01-01

    Discussion of two new techniques used to measure the lattice damage produced in GaAs by the implantation of 60 keV cadmium ions. In the first method, optical reflection spectra of the ion-implanted samples were measured in the wavelength range from 2000 to 4600 A. The decrease in reflectivity resulting from ion-implantation was used to determine the relative amount of lattice damage as a function of ion dose. The second technique employed the scanning electron microscope. Patterns very similar in appearance to Kikuchi electron diffraction patterns are obtained when the secondary and/or backscattered electron intensity is displayed as a function of the angle of incidence of the electron beam on a single crystal surface. The results of measurements made by both methods are compared with each other and with data obtained by the method of measuring lattice damage by Rutherford scattering of 1 MeV helium ions.

  6. How MRI Compatible is 'MRI Compatible'? A Systematic Comparison of Artifacts Caused by Biopsy Needles at 3.0 and 1.5 T

    SciTech Connect

    Penzkofer, Tobias; Peykan, Nilufar; Schmidt, Katja; Krombach, Gabriele; Kuhl, Christiane K.

    2013-12-15

    Purpose: This study was designed to systematically investigate artifacts caused by interventional needles recommended for use in MRI, with focus on field strength, needle/mandrin type, orientation and sequence. Methods: Eight different MRI compatible needles were placed in porcine tissue and examined at 1.5 and 3.0 T with balanced-steady-state-free-precession (B-SSFP) and T1-weighted-spoiled-gradient-echo (T1-SPGR) sequences in different orientations to B{sub 0}. Artifact diameters with regards to the primary, inner, and secondary, outer artifacts were assessed and statistically evaluated. Results: The types and degree of artifacts varied considerably, especially between different mandrin types even for the same needles. Orientation of the needle in the magnetic field was another main contributor to the artifact dimensions. Less important factors were the type of pulse sequence and field strength. Artifacts ranged from 0.7 mm (steel, 0 Degree-Sign , B-SSFP, 3.0 T, inner) to 71.4 mm (nitinol, 90 Degree-Sign , B-SSFP, 1.5 T, outer). Inner artifact diameters in B-SSFP were slightly larger (8.2 {+-} 5.7 mm) than those in T1-SPGR (7.6 {+-} 5.4 mm) and comparable between 1.5 and 3.0 T (e.g., 8.0 vs. 8.4 mm, B-SSFP). Conclusions: Although all were sold as 'MR compatible,' the artifacts differed greatly between needle types, and even more so for different mandrins. The results suggest an empirical approach to the needle choice based on lesion type and approach angle.

  7. Ganglion causing paralysis of the suprascapular nerve. Diagnosis by MRI and ultrasonography.

    PubMed

    Takagishi, K; Maeda, K; Ikeda, T; Itoman, M; Yamamoto, M

    1991-08-01

    A 26-year-old man had a right infraspinatus muscle weakness and aching of the shoulder due to suprascapular nerve entrapment confirmed by electromyography. MRI revealed a well-defined area of increased signal intensity over the suprascapular notch. An ultrasonogram showed a homogeneous hypoechogenic area at the base of the scapular spine. A diagnosis was made of a ganglion compressing the inferior branch of the suprascapular nerve. After removal of several ganglia, the patient had immediate pain relief, and normal electromyographic findings were obtained 5 months postoperatively. PMID:1882686

  8. Bacterial Biofilms on Implanted Suture Material Are a Cause of Surgical Site Infection

    PubMed Central

    Nistico, Laura; Tower, Irene; Lasko, Leslie-Ann; Stoodley, Paul

    2014-01-01

    Abstract Background: Surgical site infection (SSI) has been estimated to occur in up to 5% of all procedures, accounting for up to 0.5% of all hospital costs. Bacterial biofilms residing on implanted foreign bodies have been implicated as contributing or causative factors in a wide variety of infectious scenarios, but little consideration has been given to the potential for implanted, submerged suture material to act as a host for biofilm and thus serve as a nidus of infection. Methods: We report a series of 15 patients who underwent open Roux-en-Y gastric bypass (with musculofascial closure with permanent, multifilament sutures) who developed longstanding and refractory SSIs in the abdominal wall. Explanted suture material at subsequent exploration was examined for biofilm with confocal laser-scanning microscopy (CLSM) and fluorescence in situ hybridization (FISH). Results: All 15 patients at re-exploration were found to have gross evidence of a “slimy” matrix or dense reactive granulation tissue localized to the implanted sutures. Confocal laser-scanning microscopy revealed abundant biofilm present on all sutures examined; FISH was able to identify the presence of specific pathogens in the biofilm. Complete removal of the foreign bodies (and attendant biofilms) resulted in all cases in cure of the SSI. Conclusion: Bacterial biofilms on implanted suture material can manifest as persistent surgical site infections that require complete removal of the underlying foreign body substrata for resolution. PMID:24833403

  9. Bruxism: its multiple causes and its effects on dental implants - an updated review.

    PubMed

    Lobbezoo, F; Van Der Zaag, J; Naeije, M

    2006-04-01

    There is a growing interest in bruxism, as evidenced by the rapidly increasing number of papers about this subject during the past 5 years. The aim of the present review was to provide an update of two previous reviews from our department (one about the aetiology of bruxism and the other about the possible role of this movement disorder in the failure of dental implants) and to describe the details of the literature search strategies used, thus enabling the readers to judge the completeness of the review. Most studies that were published about the etiology during the past 5 years corroborate the previously drawn conclusions. Similarly, the update of the review about the possible causal relationship between bruxism and implant failure reveals no new points of view. Thus, there is no reason to assume otherwise than that bruxism is mainly regulated centrally, not peripherally, and that there is still insufficient evidence to support or refute a causal relationship between bruxism and implant failure. This illustrates that there is a vast need for well-designed studies to study both the aetiology of bruxism and its purported relationship with implant failure. PMID:16629884

  10. Serratia marcescens: A Rare Cause of Recurrent Implantable Cardioverter Defibrillator Site Infection

    PubMed Central

    Hawkey, S.; Choy, AM.

    2015-01-01

    We present a unique case of a patient who experienced recurrent infections of his implantable cardioverter defibrillator (ICD) site with the bacterium Serratia marcescens. This report highlights the virulence of this bacterium, its resistance to antibiotic therapy, and its ability to remain latent for prolonged periods between episodes of sepsis. It also demonstrates the merits of reimplanting devices at different sites in the context of Serratia marcescens infection. PMID:26605092

  11. Late migration of an orbital implant causing orbital hemorrhage with sudden proptosis and diplopia.

    PubMed

    Rosen, C E

    1996-12-01

    A 31-year-old woman complained of sudden diplopia and proptosis associated with a headache. Approximately 10 years earlier, she had sustained a right orbital blowout fracture during a snow machine accident that was repaired using a Supramid implant. She presented with 4 mm of right-sided proptosis by Hertel exophthalmometry, with limitation of up and down gaze. She manifested a right gaze preference with a left head turn to achieve fusion. Visual acuity was 20/20 on both sides; however, there was 20% red desaturation and a subtle afferent pupillary defect on the right side. Goldmann visual fields were full and the retinal examination was normal. A computed tomography (CT) scan of the orbits with and without contrast demonstrated a large right posterior inferior orbital mass. Once the periorbita was breached during orbitotomy, a burgundy serosanguinous material emerged. Gram staining revealed red cells without organisms. The implant had not been fixed by wires or screws. Upon removal, the implant appeared oversized, encompassing the orbital floor, medial and lateral walls. Postoperatively, the proptosis, gaze preference with face turn, afferent pupillary defect, desaturation abnormality, and diplopia resolved. PMID:8944386

  12. Capsular contracture by silicone breast implants: possible causes, biocompatibility, and prophylactic strategies.

    PubMed

    Steiert, Andreas E; Boyce, Maria; Sorg, Heiko

    2013-01-01

    The most common implanted material in the human body consists of silicone. Breast augmentation and breast reconstruction using silicone-based implants are procedures frequently performed by reconstructive and aesthetic surgeons. A main complication of this procedure continues to be the development of capsular contracture (CC), displaying the result of a fibrotic foreign body reaction after the implantation of silicone. For many years, experimental and clinical trials have attempted to analyze the problem of its etiology, treatment, and prophylaxis. Different theories of CC formation are known; however, the reason why different individuals develop CC in days or a month, or only after years, is unknown. Therefore, we hypothesize that CC formation, might primarily be induced by immunological mechanisms along with other reasons. This article attempts to review CC formation, with special attention paid to immunological and inflammatory reasons, as well as actual prophylactic strategies. In this context, the word "biocompatibility" has been frequently used to describe the overall biological innocuousness of silicone in the respective studies, although without clear-cut definitions of this important feature. We have therefore developed a new five-point scale with distinct key points of biocompatibility. Hence, this article might provide the basis for ongoing discussion in this field to reduce single-publication definitions as well as increase the understanding of biocompatibility. PMID:24324348

  13. Interference from a hand held radiofrequency remote control causing discharge of an implantable defibrillator.

    PubMed

    Man, K C; Davidson, T; Langberg, J J; Morady, F; Kalbfleisch, S J

    1993-08-01

    A 46-year-old man with a history of sustained monomorphic ventricular tachycardia underwent an implantation of a third generation multiprogrammable implantable cardioverter defibrillator. One year post implant, while manipulating a remote control to a radiofrequency modulated toy car, the patient experienced a defibrillator discharge not preceded by an arrhythmia prodrome. Subsequent interrogation of the defibrillator revealed that a 34-joule shock had been delivered and had been preceded by RR intervals ranging from 141-406 msec, consistent with sensing lead noise. The remote control utilizes a 12-volt battery and has a carrier frequency of 75.95 MHz and a modulating frequency of 50 Hz. Evaluation of the remote control and defibrillator interaction revealed that the remote control was able to trigger tachyarrhythmia sensing and reproduce the clinical episode. Interference was present only when the remote control was within 8 cm of the pulse generator and at specific angles relative to the device and only when the antenna length was > 45 cm. Interference was eliminated when a ground wire was attached to the antenna and when an aluminium shield was placed between the pulse generator and the remote control. This case report suggests that patients with third generation multiprogrammable defibrillators should be cautioned against close contact with potential sources of electromagnetic interference, such as remote control units. PMID:7690947

  14. Diffusional kurtosis MRI of the lower leg: changes caused by passive muscle elongation and shortening.

    PubMed

    Filli, Lukas; Kenkel, David; Wurnig, Moritz C; Boss, Andreas

    2016-06-01

    Diffusional kurtosis MRI (DKI) quantifies the deviation of water diffusion from a Gaussian distribution. We investigated the influence of passive elongation and shortening of the lower leg muscles on the DKI parameters D (diffusion coefficient) and K (kurtosis). After approval by the local ethics committee, eight healthy volunteers (age, 29.1 ± 2.9 years) underwent MRI of the lower leg at 3 T. Diffusion-weighted images were acquired with 10 different b values at three ankle positions (passive dorsiflexion 10°, neutral position 0°, passive plantar flexion 40°). Parametrical maps of D and K were obtained by voxel-wise fitting of the signal intensities using a non-linear Levenberg-Marquardt algorithm. D and K were measured in the tibialis anterior, medial and lateral gastrocnemius, and soleus muscles. In the neutral position, D and K values were in the range between 1.66-1.79 × 10(-3) mm(2) /s and 0.21-0.39, respectively. D and K increased with passive shortening, and decreased with passive elongation, which could also be illustrated on the parametrical maps. In dorsiflexion, D (p < 0.01) and K (p = 0.036) were higher in the tibialis anterior than in the medial gastrocnemius. In plantar flexion, the opposite was found for K (p = 0.035). DKI parameters in the lower leg muscles are significantly influenced by the ankle joint position, indicating that the diffusion of water molecules in skeletal muscle deviates from a Gaussian distribution depending on muscle tonus. Copyright © 2016 John Wiley & Sons, Ltd. PMID:27061811

  15. Evidence of healing of partial-thickness rotator cuff tears following arthroscopic augmentation with a collagen implant: a 2-year MRI follow-up

    PubMed Central

    Bokor, Desmond John; Sonnabend, David; Deady, Luke; Cass, Ben; Young, Allan; Van Kampen, Craig; Arnoczky, Steven

    2016-01-01

    Summary Background partial-thickness rotator cuff tears frequently enlarge due to increased local strain and often progress to full-thickness tears. Studies suggest the addition of new tendinous tissue to injured cuff tendons would significantly decrease peak strain, possibly protecting against tear progression. The aim of this study was to assess the ability of a highly-porous collagen implant to induce new tissue formation and limit tear progression when placed on the bursal surface of partial-thickness cuff tears. Methods following arthroscopic subacromial decompression, the implant was attached to the bursal surface of the supraspinatus tendon in a prospective series of 13 consecutive patients with intermediate – (3–6 mm) to high-grade (>6 mm) partial – thickness cuff tears (5 articular, 3 bursal, 5 intra-substance). Tendon thickness, defect size, and tendon quality were evaluated using magnetic resonance imaging (MRI) preoperatively and at 3, 6, 12, and 24 months postoperatively. Clinical outcomes were assessed using the Constant and American Shoulder and Elbow Society scores at the same preoperative and follow-up times. All 13 patients completed all follow-up exams (mean length of follow-up 27.0 months, range 23.3–32.0); no patients were lost to follow-up. Results the implant induced significant new tissue formation in all patients by 3 months (mean increase in tendon thickness 2.2 ± 0.26 mm). This tissue matured over time and became radiologically indistinguishable from the underlying tendon. The partial-thickness cuff tears showed consistent filling of the defects, with complete healing in 7 patients at 12 months, and a progressive improvement in tendon quality in the remaining patients. No tear progression was observed by MRI in any of the patients at 24 months. All clinical scores improved significantly over time. At 24 months, 12 of 13 patients (92%) had satisfactory or better results. Conclusions the results of this clinical study demonstrated

  16. Updating working memory in aircraft noise and speech noise causes different fMRI activations.

    PubMed

    Saetrevik, Bjørn; Sörqvist, Patrik

    2015-02-01

    The present study used fMRI/BOLD neuroimaging to investigate how visual-verbal working memory is updated when exposed to three different background-noise conditions: speech noise, aircraft noise and silence. The number-updating task that was used can distinguish between "substitution processes," which involve adding new items to the working memory representation and suppressing old items, and "exclusion processes," which involve rejecting new items and maintaining an intact memory set. The current findings supported the findings of a previous study by showing that substitution activated the dorsolateral prefrontal cortex, the posterior medial frontal cortex and the parietal lobes, whereas exclusion activated the anterior medial frontal cortex. Moreover, the prefrontal cortex was activated more by substitution processes when exposed to background speech than when exposed to aircraft noise. These results indicate that (a) the prefrontal cortex plays a special role when task-irrelevant materials should be denied access to working memory and (b) that, when compensating for different types of noise, either different cognitive mechanisms are involved or those cognitive mechanisms that are involved are involved to different degrees. PMID:25352319

  17. Updating working memory in aircraft noise and speech noise causes different fMRI activations

    PubMed Central

    Sætrevik, Bjørn; Sörqvist, Patrik

    2015-01-01

    The present study used fMRI/BOLD neuroimaging to investigate how visual-verbal working memory is updated when exposed to three different background-noise conditions: speech noise, aircraft noise and silence. The number-updating task that was used can distinguish between “substitution processes,” which involve adding new items to the working memory representation and suppressing old items, and “exclusion processes,” which involve rejecting new items and maintaining an intact memory set. The current findings supported the findings of a previous study by showing that substitution activated the dorsolateral prefrontal cortex, the posterior medial frontal cortex and the parietal lobes, whereas exclusion activated the anterior medial frontal cortex. Moreover, the prefrontal cortex was activated more by substitution processes when exposed to background speech than when exposed to aircraft noise. These results indicate that (a) the prefrontal cortex plays a special role when task-irrelevant materials should be denied access to working memory and (b) that, when compensating for different types of noise, either different cognitive mechanisms are involved or those cognitive mechanisms that are involved are involved to different degrees. PMID:25352319

  18. Mast cells rescue implantation defects caused by c-kit deficiency

    PubMed Central

    Woidacki, K; Popovic, M; Metz, M; Schumacher, A; Linzke, N; Teles, A; Poirier, F; Fest, S; Jensen, F; Rabinovich, G A; Maurer, M; Zenclussen, A C

    2013-01-01

    Various physiologically relevant processes are regulated by the interaction of the receptor tyrosine kinase (c-Kit) and its ligand stem cell factor (SCF), with SCF known to be the most important growth factor for mast cells (MCs). In spite of their traditional role in allergic disorders and innate immunity, MCs have lately emerged as versatile modulators of a variety of physiologic and pathologic processes. Here we show that MCs are critical for pregnancy success. Uterine MCs presented a unique phenotype, accumulated during receptivity and expanded upon pregnancy establishment. KitW-sh/W-sh mice, whose MC deficiency is based on restricted c-Kit gene expression, exhibited severely impaired implantation, which could be completely rescued by systemic or local transfer of wild-type bone marrow-derived MCs. Transferred wild-type MCs favored normal implantation, induced optimal spiral artery remodeling and promoted the expression of MC proteases, transforming growth factor-β and connective tissue growth factor. MCs contributed to trophoblast survival, placentation and fetal growth through secretion of the glycan-binding protein galectin-1. Our data unveil unrecognized roles for MCs at the fetomaternal interface with critical implications in reproductive medicine. PMID:23328669

  19. Implantable cardioverter defibrillator dysfunction during and after magnetic resonance imaging.

    PubMed

    Anfinsen, Ole-Gunnar; Berntsen, Rolf Franck; Aass, Halfdan; Kongsgaard, Erik; Amlie, Jan Peder

    2002-09-01

    This report describes a patient in whom a MRI of the brain was performed without realizing that an ICD had been implanted 8 days previously. Electromagnetic noise induced during the MRI was detected as ventricular fibrillation and nearly caused inappropriate shocks. Charge time during MRI was prolonged. The battery indicator switched to "end of life," but this was reversed by capacitor reformation. These problems could have been avoided by inactivating the ICD prior to MRI. Three months later, the pacing threshold increased from 0.4 V per 0.5 ms at implantation to 2.8 V per 0.5. It is still uncertain whether radiofrequency current heating at the electrode tip caused the increased pacing threshold or if this would have occurred independently of the MRI. MRI of patients with an active ICD may cause life-threatening complications, and it is unknown if MRI may be safely performed if the ICD is inactivated. Therefore, MRI of patients with an ICD remains contraindicated. PMID:12380781

  20. Clostridium novyi-NT can cause regression of orthotopically implanted glioblastomas in rats

    PubMed Central

    Sun, Weiyun; Huang, Judy; Kibler, Kathleen Kazuko; Tyler, Betty M.; Gallia, Gary L.; Kinzler, Kenneth; Vogelstein, Bert; Zhou, Shibin; Riggins, Gregory J.

    2015-01-01

    Glioblastoma (GBM) is a highly aggressive primary brain tumor that is especially difficult to treat. The tumor's ability to withstand hypoxia leads to enhanced cancer cell survival and therapy resistance, but also yields a microenvironment that is in many aspects unique within the human body, thus offering potential therapeutic opportunities. The spore-forming anaerobic bacterium Clostridium novyi-NT(C. novyi-NT) has the ability to propagate in tumor-generated hypoxia, leading to oncolysis. Here, we show that intravenously injected spores of C. novyi-NT led to dramatic tumor destructions and significant survival increases in implanted, intracranial syngeneic F98 and human xenograft 060919 rat GBM models. C. novyi-NT germination was specific and confined to the neoplasm, with sparing of the normal brain parenchyma. All animals tolerated the bacteriolytic treatment, but edema and increased intracranial pressure could quickly be lethal if not monitored and medically managed with hydration and antibiotics. These results provide pre-clinical data supporting the development of this therapeutic approach for the treatment of patients with GBM. PMID:25849940

  1. Incidence, Causes, and Impact of In-Hospital Infections After Transcatheter Aortic Valve Implantation.

    PubMed

    Tirado-Conte, Gabriela; Freitas-Ferraz, Afonso B; Nombela-Franco, Luis; Jimenez-Quevedo, Pilar; Biagioni, Corina; Cuadrado, Ana; Nuñez-Gil, Ivan; Salinas, Pablo; Gonzalo, Nieves; Ferrera, Carlos; Vivas, David; Higueras, Javier; Viana-Tejedor, Ana; Perez-Vizcayno, Maria Jose; Vilacosta, Isidre; Escaned, Javier; Fernandez-Ortiz, Antonio; Macaya, Carlos

    2016-08-01

    In-hospital infections (IHI) are one of the most common and serious problems after invasive procedures. Transcatheter aortic valve implantation (TAVI) is an increasingly used alternative to surgery in patients with severe symptomatic aortic stenosis. The aim of this study was to determine the incidence, origin, risk factors, and clinical outcomes of IHI after TAVI. A total of 303 consecutive patients with severe aortic stenosis who underwent transfemoral TAVI were included and followed during a median time of 21 months. We examined the occurrence, types, origin, and timing of infections during hospital stay as well as short- and long-term clinical outcomes according to the occurrence of IHI. A total of 51 patients (17%; 62 infectious episodes) experienced IHI after TAVI. Respiratory and urinary tract infections were the most frequent type of infections (44% and 34%, respectively), followed by surgical site infection (8%) and bloodstream infection (5%). Positive cultures were obtained in 74% of the samples, of which 65% were gram-negative bacilli. Modifiable factors such as bleeding (p = 0.005) and length of coronary care unit stay (p <0.001) were independently associated with an increased infection risk. Patients with IHI had a longer hospital stay (14 vs 6 days, p <0.001), an increased mortality (hazard ratio 2.48, 95% CI 1.45 to 4.23) and readmission rate (hazard ratio 2.0, 95% CI 1.27 to 3.14) during the follow-up. In conclusion, IHI is a frequent complication after TAVI with a significant impact on short- and long-term clinical outcomes. The most important risk factors associated with the development of this complication were modifiable periprocedural aspects. These results underline the importance to implement specific preventive strategies to reduce in-hospital-acquired infections after TAVI. PMID:27296559

  2. A Biodistribution and Toxicity Study of Cobalt Dichloride–N-Acetyl Cysteine (C4) as an Implantable MRI Marker for Prostate Cancer Treatment

    PubMed Central

    Frank, Steven J.; Johansen, Mary J.; Martirosyan, Karen; Gagea, Mihai; Van Pelt, Carolyn S.; Borne, Agatha; Carmazzi, Yudith; Madden, Timothy

    2013-01-01

    Purpose C4, a cobalt dichloride–N-acetyl cysteine complex, is being developed as a positive-signal magnetic resonance imaging (MRI) marker to localize implanted radioactive seeds in prostate brachytherapy. We evaluated the toxicity and biodistribution of C4 in rats with the goal of simulating systemic effects of potential leakage from C4 MRI markers within the prostate. Methods 9 µl doses (equivalent to leakage from 120 markers in a human) of control (0.9% sodium chloride), 1% (proposed for clinical use) and 10% C4 solution were injected into the prostates of male Sprague-Dawley rats via laparotomy. Organ toxicity and cobalt disposition in plasma, tissues, feces and urine were evaluated. Results No C4-related morbidity or mortality was observed in the biodistribution arm (60 rats). Biodistribution was measurable following 10% C4 injection: cobalt was cleared rapidly from periprostatic tissue; mean concentrations in prostate were 163 µg/g and 268 µg/g at 5 and 30 minutes but were undetectable by 60 minutes. Expected dual renal-hepatic elimination was observed with % injected dose recovered in tissues of 39.0 ±5.6% (liver) > 11.8 ±6.5% (prostate) > 5.3 ±0.9% (kidney) with low plasma concentrations detected up to 1 hr (1.40 µg/ml at 5–60 minutes). Excretion in urine was 13.1 ±4.6 % with 3.1 ±0.54 % recovered in feces by 24 hours. In the toxicity arm, three animals died in the control group and 1 each in the 1% and 10% groups from surgical or anesthesia-related complications; all others survived to scheduled termination at 14 days. No C4-related adverse clinical signs or organ toxicity was observed. Conclusion C4-related toxicity was not observed at exposures at least 10-fold that proposed for human use. This data demonstrating lack of systemic toxicity with dual routes of elimination in the event of in-situ rupture suggests C4 warrants further investigation as an MRI marker for prostate brachytherapy. PMID:23092727

  3. A Biodistribution and Toxicity Study of Cobalt Dichloride-N-Acetyl Cysteine in an Implantable MRI Marker for Prostate Cancer Treatment

    SciTech Connect

    Frank, Steven J.; Johansen, Mary J.; Martirosyan, Karen S.; Gagea, Mihai; Van Pelt, Carolyn S.; Borne, Agatha; Carmazzi, Yudith; Madden, Timothy

    2013-03-15

    Purpose: C4, a cobalt dichloride-N-acetyl cysteine complex, is being developed as a positive-signal magnetic resonance imaging (MRI) marker to localize implanted radioactive seeds in prostate brachytherapy. We evaluated the toxicity and biodistribution of C4 in rats with the goal of simulating the systemic effects of potential leakage from C4 MRI markers within the prostate. Methods and Materials: 9-μL doses (equivalent to leakage from 120 markers in a human) of control solution (0.9% sodium chloride), 1% (proposed for clinical use), and 10% C4 solution were injected into the prostates of male Sprague-Dawley rats via laparotomy. Organ toxicity and cobalt disposition in plasma, tissues, feces, and urine were evaluated. Results: No C4-related morbidity or mortality was observed in the biodistribution arm (60 rats). Biodistribution was measurable after 10% C4 injection: cobalt was cleared rapidly from periprostatic tissue; mean concentrations in prostate were 163 μg/g and 268 μg/g at 5 and 30 minutes but were undetectable by 60 minutes. Expected dual renal-hepatic elimination was observed, with percentages of injected dose recovered in tissues of 39.0 ± 5.6% (liver), >11.8 ± 6.5% (prostate), and >5.3 ± 0.9% (kidney), with low plasma concentrations detected up to 1 hour (1.40 μg/mL at 5-60 minutes). Excretion in urine was 13.1 ± 4.6%, with 3.1 ± 0.54% recovered in feces by 24 hours. In the toxicity arm, 3 animals died in the control group and 1 each in the 1% and 10% groups from surgical or anesthesia-related complications; all others survived to scheduled termination at 14 days. No C4-related adverse clinical signs or organ toxicity were observed. Conclusion: C4-related toxicity was not observed at exposures at least 10-fold the exposure proposed for use in humans. These data demonstrating lack of systemic toxicity with dual routes of elimination in the event of in situ rupture suggest that C4 warrants further investigation as an MRI marker for prostate

  4. Classifying late-onset dementia with MRI: Is arteriosclerotic brain degeneration the most common cause of Alzheimer’s syndrome?

    PubMed Central

    Henry-Feugeas, Marie Cécile; Onen, Fannie; Claeys, Elisabeth Schouman

    2008-01-01

    Our aim was to use early magnetic resonance imaging (MRI) to investigate the causes of cognitive decline in elderly people with mild cognitive impairment (MCI). Baseline structural and flow quantification MR sequences, and clinical and neuropsychological follow-up for at least two years, were performed on 62 elderly subjects with MCI. Of these subjects, 17 progressed to dementia, and 15 of these progressed to dementia of the Alzheimer type (DAT). Conversion to clinically diagnosed DAT was related to six distinct MR profiles, including one profile suggesting severe AD (20% of these converters) and five profiles suggesting severe cerebrovascular dysfunction. Two profiles suggested arteriosclerotic brain degeneration, one profile suggested severe venous windkessel dysfunction, and two suggested marked cerebral hypoperfusion associated with very low craniospinal compliance or marked brain atrophy. As compared with vascular MR type converters, AD MR type converters showed high executive and mobility predementia performances. Severe whole anteromesial temporal atrophy and predominantly left brain atrophy on visual MR analysis was only observed in AD MR type converters. In conclusion, these observations enhance the pathogenic complexity of the Alzheimer syndrome, and suggest that the role of arteriosclerotic brain degeneration in late life dementia is underestimated. PMID:18488889

  5. Unusual cause of hypoxemia after automatic implantable cardioverter-defibrillatorleads extraction

    PubMed Central

    Raju, Dinesh; Roysam, Chandrika; Singh, Rajendra; Clark, Stephen C.; Plummer, Christopher

    2015-01-01

    The indication of pacemaker/AICD removal are numerous. Serious complication can occur during their removal, severe tricuspid regurgitation is one of the complication. The occurrence of PFO is not uncommon among adult population. Shunting across PFO in most circumstance is negligible, but in some necessitates closure due to hypoxemia. We report a case of 62 year old man, while undergoing AICD removal, had an emergency sternotomy for cardiac tamponade. Postoperatively, he experienced profound hypoxemia refractory to oxygen therapy. Transthoracic Echocardiogram was performed to rule out intracardiac shunts at an early stage, but it was difficult to obtain an good imaging windows poststernotomy. A small pulmonary emboli was noted on CTPA, but was not sufficient to account for the level of hypoxemia and did not resolve with anticoagulation. Transesophageal echocardiogram showed flail septal tricuspid valve with severe TR and bidirectional shunt through large PFO. Patient was posted for surgery, tricuspid valve was replaced and PFO surgically closed. Subsequently, patient recovered well ad was discharged to home. Cause of hypoxemia might be due to respiratory or cardiac dysfunction. But for hypoxemia refractory to oxygen therapy, transoesophageal echocardiogram should be always considered and performed early as an diagnostic tool in post cardiac surgical patients. PMID:26440254

  6. CUSTOM-FIT RADIOLUCENT CRANIAL IMPLANTS FOR NEUROPHYSIOLOGICAL RECORDING AND STIMULATION

    PubMed Central

    Mulliken, Grant H; Bichot, Narcisse P; Ghadooshahy, Azriel; Sharma, Jitendra; Kornblith, Simon; Philcock, Michael; Desimone, Robert

    2015-01-01

    Background Recording and manipulating neural activity in awake behaving animal models requires long-term implantation of cranial implants that must address a variety of design considerations, which include preventing infection, minimizing tissue damage, mechanical strength of the implant, and MRI compatibility. New Method Here we address these issues by designing legless, custom-fit cranial implants using structural MRI-based reconstruction of the skull and that are made from carbon-reinforced PEEK. Results We report several novel custom-fit radiolucent implant designs, which include a legless recording chamber, a legless stimulation chamber, a multi-channel microdrive and a head post. The fit to the skull was excellent in all cases, with no visible gaps between the base of the implants and the skull. The wound margin was minimal in size and showed no sign of infection or skin recession. Comparison with Existing Methods Cranial implants used for neurophysiological investigation in awake behaving animals often employ methyl methacrylate (MMA) to serve as a bonding agent to secure the implant to the skull. Other designs rely on radially extending legs to secure the implant. Both of these methods have significant drawbacks. MMA is toxic to bone and frequently leads to infection while radially extending legs cause the skin to recede away from the implant, ultimately exposing bone and proliferating granulation tissue. Conclusions These radiolucent implants constitute a set of technologies suitable for reliable long-term recording, which minimize infection and tissue damage. PMID:25542350

  7. Magnetic resonance imaging in patients with a subcutaneous implantable cardioverter-defibrillator

    PubMed Central

    Keller, Jiří; Neužil, Petr; Vymazal, Josef; Janotka, Marek; Brada, Jiří; Žáček, Radovan; Vopálka, Roman; Weichet, Jiří; Reddy, Vivek Y.

    2015-01-01

    Aims Our aim was to evaluate the potential for safely imaging patients with a new type of implantable cardioverter-defibrillator called the subcutaneous implantable cardioverter-defibrillator (S-ICD) in a 1.5 T magnetic resonance imaging (MRI) scanner. With the increasing number of patients with cardiac implantable devices who are indicated for MRI, there is a growing need for establishing MRI compatibility of cardiac implantable devices. Methods and Results Patients with implanted S-ICD systems underwent one or more types of anatomical MRI scans. The S-ICD was programmed off and patients were monitored throughout the imaging procedure. Device function was evaluated pre- and post-scan. Patients were asked to report immediately any pain, torqueing movement, or heating sensation in the area of the pocket or electrode. Fifteen patients underwent a total of 22 examinations at 1.5 T. Scans included brain, spine, knee, and heart. Two patients were re-scanned due to complaints of heating over the can during lumbar scans, which was caused by a thermistor probe placed on the skin to measure skin temperature. All the remaining scans occurred without incident. No evidence of device malfunction was observed. Conclusion This study is the first to domonstrate the feasibility of exposing S-ICD patients to MRI using the scanning and monitoring protocol described. More data are required to support S-ICD as a MRI conditional device. PMID:25687749

  8. Endovascular Repair of a Perforation of the Vena Caval Wall Caused by the Retrieval of a Gunther Tulip Filter After Long-Term Implantation

    SciTech Connect

    Morishita, Hiroyuki; Yamagami, Takuji; Matsumoto, Tomohiro; Takeuchi, Yoshito; Sato, Osamu; Nishimura, Tsunehiko

    2011-02-15

    Symptomatic penetration of the inferior vena cava (IVC) wall reportedly occurs in 0.3% of patients in whom a filter has been implanted, and it causes injury to the adjacent structures (Bogue et al. in Pediatr Radiol 39(10):1110-1113, 1; Brzezinski et al. in Burns 32(5):640-643, 2). We succeeded in the endovascular repair of perforation of the IVC wall occurring during the retrieval of a penetrated Gunther tulip vena cava filter (Cook, Bjaeverskov, Denmark) after long-term implantation.

  9. Delayed low frequency hearing loss caused by cochlear implantation interventions via the round window but not cochleostomy.

    PubMed

    Rowe, David; Chambers, Scott; Hampson, Amy; Eastwood, Hayden; Campbell, Luke; O'Leary, Stephen

    2016-03-01

    Cochlear implant recipients show improved speech perception and music appreciation when residual acoustic hearing is combined with the cochlear implant. However, up to one third of patients lose their pre-operative residual hearing weeks to months after implantation, for reasons that are not well understood. This study tested whether this "delayed" hearing loss was influenced by the route of electrode array insertion and/or position of the electrode array within scala tympani in a guinea pig model of cochlear implantation. Five treatment groups were monitored over 12 weeks: (1) round window implant; (2) round window incised with no implant; (3) cochleostomy with medially-oriented implant; (4) cochleostomy with laterally-oriented implant; and (5) cochleostomy with no implant. Hearing was measured at selected time points by the auditory brainstem response. Cochlear condition was assessed histologically, with cochleae three-dimensionally reconstructed to plot electrode paths and estimate tissue response. Electrode array trajectories matched their intended paths. Arrays inserted via the round window were situated nearer to the basilar membrane and organ of Corti over the majority of their intrascalar path compared with arrays inserted via cochleostomy. Round window interventions exhibited delayed, low frequency hearing loss that was not seen after cochleostomy. This hearing loss appeared unrelated to the extent of tissue reaction or injury within scala tympani, although round window insertion was histologically the most traumatic mode of implantation. We speculate that delayed hearing loss was related not to the electrode position as postulated, but rather to the muscle graft used to seal the round window post-intervention, by altering cochlear mechanics via round window fibrosis. PMID:26739790

  10. [Implant allergies].

    PubMed

    Thomas, P; Thomsen, M

    2010-03-01

    An increasing number of patients receive and benefit from osteosynthesis materials or artificial joint replacement. The most common complications are mechanical problems or infection. Metals like nickel, chromium and cobalt as well as bone cement components like acrylates and gentamicin are potential contact allergens which can cause intolerance reactions to implants. Eczema, delayed wound/bone healing, recurrent effusions, pain and implant loosening all have been described as manifestation of implant allergy. In contrast to the high incidence of cutaneous metal allergy, allergies associated with implants are rare. Diagnosis of metal implant allergy is still difficult. Thus differential diagnoses--in particular infection--have to be excluded and a combined approach of allergologic diagnostics by patch test and histopathology of peri-implant tissue is recommended. It is still unknown which conditions induce allergic sensitization to implants or trigger peri-implant allergic reactions in the case of preexisting cutaneous metal allergy. Despite the risk of developing complications being unclear, titanium based osteosynthesis materials are recommended for metal allergic patients and the use of metal-metal couplings in arthroplasty is not recommended for such patients. If the regular CoCr-polyethylene articulation is employed, the patient should give informed written consent. PMID:20204719

  11. Head MRI

    MedlinePlus

    ... the head; MRI - cranial; NMR - cranial; Cranial MRI; Brain MRI; MRI - brain; MRI - head ... tell your health care provider if you have: Brain aneurysm clips Certain types of artificial heart valves ...

  12. Retrograde peri-implantitis.

    PubMed

    Mohamed, Jumshad B; Shivakumar, B; Sudarsan, Sabitha; Arun, K V; Kumar, T S S

    2010-01-01

    Retrograde peri-implantitis constitutes an important cause for implant failure. Retrograde peri-implantitis may sometimes prove difficult to identify and hence institution of early treatment may not be possible. This paper presents a report of four cases of (the implant placed developing to) retrograde peri-implantitis. Three of these implants were successfully restored to their fully functional state while one was lost due to extensive damage. The paper highlights the importance of recognizing the etiopathogenic mechanisms, preoperative assessment, and a strong postoperative maintenance protocol to avoid retrograde peri-implant inflammation. PMID:20922082

  13. Urinary incontinence - injectable implant

    MedlinePlus

    Injectable implants are injections of material into the urethra to help control urine leakage ( urinary incontinence ) caused by a ... into the tissue next to the sphincter. The implant procedure is usually done in the hospital. Or ...

  14. Optogenetic Functional MRI.

    PubMed

    Lin, Peter; Fang, Zhongnan; Liu, Jia; Lee, Jin Hyung

    2016-01-01

    The investigation of the functional connectivity of precise neural circuits across the entire intact brain can be achieved through optogenetic functional magnetic resonance imaging (ofMRI), which is a novel technique that combines the relatively high spatial resolution of high-field fMRI with the precision of optogenetic stimulation. Fiber optics that enable delivery of specific wavelengths of light deep into the brain in vivo are implanted into regions of interest in order to specifically stimulate targeted cell types that have been genetically induced to express light-sensitive trans-membrane conductance channels, called opsins. fMRI is used to provide a non-invasive method of determining the brain's global dynamic response to optogenetic stimulation of specific neural circuits through measurement of the blood-oxygen-level-dependent (BOLD) signal, which provides an indirect measurement of neuronal activity. This protocol describes the construction of fiber optic implants, the implantation surgeries, the imaging with photostimulation and the data analysis required to successfully perform ofMRI. In summary, the precise stimulation and whole-brain monitoring ability of ofMRI are crucial factors in making ofMRI a powerful tool for the study of the connectomics of the brain in both healthy and diseased states. PMID:27167840

  15. Optogenetic Functional MRI

    PubMed Central

    Lin, Peter; Fang, Zhongnan; Liu, Jia; Lee, Jin Hyung

    2016-01-01

    The investigation of the functional connectivity of precise neural circuits across the entire intact brain can be achieved through optogenetic functional magnetic resonance imaging (ofMRI), which is a novel technique that combines the relatively high spatial resolution of high-field fMRI with the precision of optogenetic stimulation. Fiber optics that enable delivery of specific wavelengths of light deep into the brain in vivo are implanted into regions of interest in order to specifically stimulate targeted cell types that have been genetically induced to express light-sensitive trans-membrane conductance channels, called opsins. fMRI is used to provide a non-invasive method of determining the brain's global dynamic response to optogenetic stimulation of specific neural circuits through measurement of the blood-oxygen-level-dependent (BOLD) signal, which provides an indirect measurement of neuronal activity. This protocol describes the construction of fiber optic implants, the implantation surgeries, the imaging with photostimulation and the data analysis required to successfully perform ofMRI. In summary, the precise stimulation and whole-brain monitoring ability of ofMRI are crucial factors in making ofMRI a powerful tool for the study of the connectomics of the brain in both healthy and diseased states. PMID:27167840

  16. SU-E-J-205: Dose Distribution Differences Caused by System Related Geometric Distortion in MRI-Guided Radiation Treatment System

    SciTech Connect

    Wang, J; Yang, J; Wen, Z; Marshall, S; Court, L; Ibbott, G

    2015-06-15

    Purpose: MRI has superb soft tissue contrast but is also known for geometric distortions. The concerns and uncertainty about MRI’s geometric distortion have contributed to the hesitation of using only MRI for simulation in radiation therapy. There are two major categories of geometric distortion in MRI; system related and patient related. In this presentation, we studied the impact of system-related geometric distortion on dose distribution in a digital body phantom under an MR-Linac environment. Methods: Residual geometric distortion (after built-in geometric correction) was modeled based on phantom measurements of the system-related geometric distortions of a MRI scanner of a combined MR guided Radiation Therapy (MRgRT) system. A digital oval shaped phantom (40×25 cm) as well as one ellipsoid shaped tumor volume was created to simulate a simplified human body. The simulated tumor volume was positioned at several locations between the isocenter and the body surface. CT numbers in HUs that approximate soft tissue and tumor were assigned to the respective regions in the digital phantom. To study the effect of geometric distortion caused by system imperfections, an IMRT plan was optimized with the distorted image set with the B field. Dose distributions were re-calculated on the undistorted image set with the B field (as in MR-Linac). Results: The maximum discrepancies in both body contour and tumor boundary was less than 2 mm, which leads to small dose distribution change. For the target in the center, coverage was reduced from 98.8% (with distortion) to 98.2%; for the other peripheral target coverage was reduced from 98.4% to 95.9%. Conclusion: System related geometric distortions over the 40×25 area were within 2mm and the resulted dosimetric effects were minor for the two tumor locations in the phantom. Patient study will be needed for further investigation. The authors received a corporate research grant from Elekta.

  17. Removal of the broken part of implantable cardioverter-defibrillator's electrode causing pulmonary embolism via femoral vein.

    PubMed

    Zencir, Cemil; Selvi, Mithat; Elbi, Huseyin; Cetin, Mustafa; Gungor, Hasan; Akgullu, Cagdas; Badak, Muharrem Ismail

    2015-12-01

    A 66-year-old patient with idiopathic dilated cardiomyopathy underwent transvenous extraction of an implantable cardioverter-defibrillator. The distal part of the electrode was broken during manual traction through the left subclavian vein. In the present case, we showed a rare complication of transvenous lead extraction and its management. PMID:26995444

  18. Magnetic Resonance Imaging Compatibility of the Polymer-based Cochlear Implant

    PubMed Central

    Kim, Jin Ho; Min, Kyou Sik; An, Soon Kwan; Jeong, Joon Soo; Jun, Sang Beom; Cho, Min Hyoung; Son, Young-Don; Cho, Zang-Hee

    2012-01-01

    Objectives In this study, we compared the magnetic resonance (MR) image artifacts caused by a conventional metal-based cochlear implant and a newly developed liquid crystal polymer (LCP)-based device. Methods The metal-based cochlear implant system (Nurobiosys Co.) was attached to side of the head of a subject and the LCP-based device was attached to opposite side. In both devices, alignment magnets were removed for safety. Magnetic resonance imaging (MRI) was performed on a widely used 3.0 T and an ultra-high 7.0 T MRI machine. 3.0 and 7.0 T MR images were acquired using T1- and T2*-weighted gradient echo sequences, respectively. Results In the 3.0 T images, the metal-based device on the left side generated the significant amount of artifacts. The MR images in the proximity of the metal package were obscured by the artifacts in both axial and sagittal views. On the other hand, the MR images near the LCP-based device were relatively free from the artifacts and clearly showed the brain structures. 7.0 T MR images showed the more severe distortion in the both sides but the metal-based cochlear implant system caused a much larger obscure area than the LCP-based system. Conclusion The novel LCP-based cochlear implant provides a good MRI compatibility beyond present-day cochlear implants. Thus, MR images can be obtained from the subjects even with the implanted LCP-based neural prosthetic systems providing useful diagnostic information. Furthermore, it will be also useful for functional MRI studies of the auditory perception mechanism after cochlear implantations as well as for positron emission tomography-MRI hybrid imaging. PMID:22701769

  19. Significant Artifact Reduction at 1.5T and 3T MRI by the Use of a Cochlear Implant with Removable Magnet: An Experimental Human Cadaver Study

    PubMed Central

    Wagner, Franca; Wimmer, Wilhelm; Leidolt, Lars; Vischer, Mattheus; Weder, Stefan; Wiest, Roland; Mantokoudis, Georgios; Caversaccio, Marco D.

    2015-01-01

    Objective Cochlear implants (CIs) are standard treatment for postlingually deafened individuals and prelingually deafened children. This human cadaver study evaluated diagnostic usefulness, image quality and artifacts in 1.5T and 3T magnetic resonance (MR) brain scans after CI with a removable magnet. Methods Three criteria (diagnostic usefulness, image quality, artifacts) were assessed at 1.5T and 3T in five cadaver heads with CI. The brain magnetic resonance scans were performed with and without the magnet in situ. The criteria were analyzed by two blinded neuroradiologists, with focus on image distortion and limitation of the diagnostic value of the acquired MR images. Results MR images with the magnet in situ were all compromised by artifacts caused by the CI. After removal of the magnet, MR scans showed an unequivocal artifact reduction with significant improvement of the image quality and diagnostic usefulness, both at 1.5T and 3T. Visibility of the brain stem, cerebellopontine angle, and parieto-occipital lobe ipsilateral to the CI increased significantly after magnet removal. Conclusions The results indicate the possible advantages for 1.5T and 3T MR scanning of the brain in CI carriers with removable magnets. Our findings support use of CIs with removable magnets, especially in patients with chronic intracranial pathologies. PMID:26200775

  20. Peri-implantation lethality in mice carrying megabase-scale deletion on 5qc3.3 is caused by Exoc1 null mutation

    PubMed Central

    Mizuno, Seiya; Takami, Kohei; Daitoku, Yoko; Tanimoto, Yoko; Dinh, Tra Thi Huong; Mizuno-Iijima, Saori; Hasegawa, Yoshikazu; Takahashi, Satoru; Sugiyama, Fumihiro; Yagami, Ken-ichi

    2015-01-01

    We found a novel spontaneous mouse mutant with depigmentation in the ventral body, which we called White Spotting (WS) mouse. Genetic investigation revealed deletion of a > 1.2-Mb genomic region containing nine genes (Kit, Kdr, Srd5a3, Tmeme165, Clock, Pdcl2, Nmu, Exoc1, and Cep135). We designated this mutant allele KitWS. Interestingly, homozygous mutants (KitWS/WS) showed a peri-implantation lethal phenotype. Expression analyses of these nine genes in blastocysts suggested that Exoc1 was a prime candidate for this phenotype. We produced Exoc1 knockout mice, and the same peri-implantation lethal phenotype was seen in Exoc1−/− embryos. In addition, the polygenic effect without Exoc1 was investigated in genome-edited KitWE mice carrying the Mb-scale deletion induced by the CRISPR/Cas9 system. As KitWE/WE embryos did not exhibit the abnormal phenotype, which was seen in KitWS/WS. We concluded that peri-implantation lethality in KitWS/WS was caused by a monogenic defect of Exoc1. PMID:26346620

  1. A Novel Brain Stimulation Technology Provides Compatibility with MRI

    PubMed Central

    Serano, Peter; Angelone, Leonardo M.; Katnani, Husam; Eskandar, Emad; Bonmassar, Giorgio

    2015-01-01

    Clinical electrical stimulation systems — such as pacemakers and deep brain stimulators (DBS) — are an increasingly common therapeutic option to treat a large range of medical conditions. Despite their remarkable success, one of the significant limitations of these medical devices is the limited compatibility with magnetic resonance imaging (MRI), a standard diagnostic tool in medicine. During an MRI exam, the leads used with these devices, implanted in the body of the patient, act as an electric antenna potentially causing a large amount of energy to be absorbed in the tissue, which can lead to serious heat-related injury. This study presents a novel lead design that reduces the antenna effect and allows for decreased tissue heating during MRI. The optimal parameters of the wire design were determined by a combination of computational modeling and experimental measurements. The results of these simulations were used to build a prototype, which was tested in a gel phantom during an MRI scan. Measurement results showed a three-fold decrease in heating when compared to a commercially available DBS lead. Accordingly, the proposed design may allow a significantly increased number of patients with medical implants to have safe access to the diagnostic benefits of MRI. PMID:25924189

  2. Microfractures in metal-ceramic and all-ceramic implant-supported fixed dental prostheses caused by superstructure fixation.

    PubMed

    Karl, Matthias; Graef, Friedrich; Wichmann, Manfred; Beck, Nina

    2012-01-01

    The effect of ceramic veneering on the passivity of fit of cast metal and CAD/CAM-fabricated zirconia ceramic implant-supported three-unit cement-retained restorations was investigated, as well as the effect of misfit stress on the marginal integrity of ceramic veneers. Superstructures were fabricated using cast metal or by CAD/CAM milling of presintered or HIP zirconia ceramic (n=10). Before and after veneering, strain gages were used to measure in vitro the strain developed in all the restorations as a result of superstructure fixation. Fluorescent penetrant method was used to detect microcracks developed in ceramic veneers. Cast frameworks showed significantly higher strain values than CAD/CAM frameworks (p=0.000). Veneering significantly increased strain development in all CAD/CAM frameworks (p=0.000). Compared to zirconia ceramic restorations, significantly more microcracks were observed in cast restorations (p=0.000) both before and after superstructure fixation. PMID:22673463

  3. Congenital and prolonged adult-onset deafness cause distinct degradations in neural ITD coding with bilateral cochlear implants.

    PubMed

    Hancock, Kenneth E; Chung, Yoojin; Delgutte, Bertrand

    2013-06-01

    Bilateral cochlear implant (CI) users perform poorly on tasks involving interaural time differences (ITD), which are critical for sound localization and speech reception in noise by normal-hearing listeners. ITD perception with bilateral CI is influenced by age at onset of deafness and duration of deafness. We previously showed that ITD coding in the auditory midbrain is degraded in congenitally deaf white cats (DWC) compared to acutely deafened cats (ADC) with normal auditory development (Hancock et al., J. Neurosci, 30:14068). To determine the relative importance of early onset of deafness and prolonged duration of deafness for abnormal ITD coding in DWC, we recorded from single units in the inferior colliculus of cats deafened as adults 6 months prior to experimentation (long-term deafened cats, LTDC) and compared neural ITD coding between the three deafness models. The incidence of ITD-sensitive neurons was similar in both groups with normal auditory development (LTDC and ADC), but significantly diminished in DWC. In contrast, both groups that experienced prolonged deafness (LTDC and DWC) had broad distributions of best ITDs around the midline, unlike the more focused distributions biased toward contralateral-leading ITDs present in both ADC and normal-hearing animals. The lack of contralateral bias in LTDC and DWC results in reduced sensitivity to changes in ITD within the natural range. The finding that early onset of deafness more severely degrades neural ITD coding than prolonged duration of deafness argues for the importance of fitting deaf children with sound processors that provide reliable ITD cues at an early age. PMID:23462803

  4. Adhesions to Mesh after Ventral Hernia Mesh Repair Are Detected by MRI but Are Not a Cause of Long Term Chronic Abdominal Pain

    PubMed Central

    Langbach, Odd; Holmedal, Stein Harald; Grandal, Ole Jacob

    2016-01-01

    Aim. The aim of the present study was to perform MRI in patients after ventral hernia mesh repair, in order to evaluate MRI's ability to detect intra-abdominal adhesions. Materials and Methods. Single-center long term follow-up study of 155 patients operated for ventral hernia with laparoscopic (LVHR) or open mesh repair (OVHR), including analyzing medical records, clinical investigation with patient-reported pain (VAS-scale), and MRI. MRI was performed in 124 patients: 114 patients (74%) after follow-up, and 10 patients referred for late complaints after ventral mesh repair. To verify the MRI-diagnosis of adhesions, laparoscopy was performed after MRI in a cohort of 20 patients. Results. MRI detected adhesions between bowel and abdominal wall/mesh in 60% of the patients and mesh shrinkage in 20–50%. Adhesions were demonstrated to all types of meshes after both LVHR and OVHR with a sensitivity of 70%, specificity of 75%, positive predictive value of 78%, and negative predictive value of 67%. Independent predictors for formation of adhesions were mesh area as determined by MRI and Charlson index. The presence of adhesions was not associated with more pain. Conclusion. MRI can detect adhesions between bowel and abdominal wall in a fair reliable way. Adhesions are formed both after open and laparoscopic hernia mesh repair and are not associated with chronic pain. PMID:26819601

  5. Adhesions to Mesh after Ventral Hernia Mesh Repair Are Detected by MRI but Are Not a Cause of Long Term Chronic Abdominal Pain.

    PubMed

    Langbach, Odd; Holmedal, Stein Harald; Grandal, Ole Jacob; Røkke, Ola

    2016-01-01

    Aim. The aim of the present study was to perform MRI in patients after ventral hernia mesh repair, in order to evaluate MRI's ability to detect intra-abdominal adhesions. Materials and Methods. Single-center long term follow-up study of 155 patients operated for ventral hernia with laparoscopic (LVHR) or open mesh repair (OVHR), including analyzing medical records, clinical investigation with patient-reported pain (VAS-scale), and MRI. MRI was performed in 124 patients: 114 patients (74%) after follow-up, and 10 patients referred for late complaints after ventral mesh repair. To verify the MRI-diagnosis of adhesions, laparoscopy was performed after MRI in a cohort of 20 patients. Results. MRI detected adhesions between bowel and abdominal wall/mesh in 60% of the patients and mesh shrinkage in 20-50%. Adhesions were demonstrated to all types of meshes after both LVHR and OVHR with a sensitivity of 70%, specificity of 75%, positive predictive value of 78%, and negative predictive value of 67%. Independent predictors for formation of adhesions were mesh area as determined by MRI and Charlson index. The presence of adhesions was not associated with more pain. Conclusion. MRI can detect adhesions between bowel and abdominal wall in a fair reliable way. Adhesions are formed both after open and laparoscopic hernia mesh repair and are not associated with chronic pain. PMID:26819601

  6. Dental Implant Systems

    PubMed Central

    Oshida, Yoshiki; Tuna, Elif B.; Aktören, Oya; Gençay, Koray

    2010-01-01

    Among various dental materials and their successful applications, a dental implant is a good example of the integrated system of science and technology involved in multiple disciplines including surface chemistry and physics, biomechanics, from macro-scale to nano-scale manufacturing technologies and surface engineering. As many other dental materials and devices, there are crucial requirements taken upon on dental implants systems, since surface of dental implants is directly in contact with vital hard/soft tissue and is subjected to chemical as well as mechanical bio-environments. Such requirements should, at least, include biological compatibility, mechanical compatibility, and morphological compatibility to surrounding vital tissues. In this review, based on carefully selected about 500 published articles, these requirements plus MRI compatibility are firstly reviewed, followed by surface texturing methods in details. Normally dental implants are placed to lost tooth/teeth location(s) in adult patients whose skeleton and bony growth have already completed. However, there are some controversial issues for placing dental implants in growing patients. This point has been, in most of dental articles, overlooked. This review, therefore, throws a deliberate sight on this point. Concluding this review, we are proposing a novel implant system that integrates materials science and up-dated surface technology to improve dental implant systems exhibiting bio- and mechano-functionalities. PMID:20480036

  7. [Actuality with the breast implants].

    PubMed

    Duchateau, J

    2013-09-01

    The author presents the history of breast implants, and the modern evolution where breast implants are largely used in both cosmetic and reconstructive surgery. Breast augmentation is one of the most performed cosmetic procedures, with a high satisfaction rate. However, one needs to remind that breast implants have a limited duration of life. The estimated rate of breast implant rupture after 10 years is of 10% in the current literature, This rate will probably become lower with the new more cohesive implants recently available on the market. It is therefore essential to propose a regular follow-up to all patients having breast implants. This follow-up is performed using a combination of physical examination, mammograms, ultrasound and MRI. The more specific therapeutic approach for patients having a PIP prosthesis will also be discussed. PMID:24195240

  8. Cochlear Implants.

    ERIC Educational Resources Information Center

    Clark, Catherine; Scott, Larry

    This brochure explains what a cochlear implant is, lists the types of individuals with deafness who may be helped by a cochlear implant, describes the process of evaluating people for cochlear implants, discusses the surgical process for implanting the aid, traces the path of sound through the cochlear implant to the brain, notes the costs of…

  9. [Imaging in silicone breast implantation].

    PubMed

    Gielens, Maaike P M; Koolen, Pieter G L; Hermens, Roland A E C; Rutten, Matthieu J C M

    2013-01-01

    Recently, there have been concerns regarding the use of breast implants from Poly Implant Prothèse (PIP, Seyne sur Mer, France) for breast augmentation due to their tendency to rupture and the possibility of having toxic contents. MRI using a specific silicone-sensitive sequence has proven to be the most sensitive and specific technique in the detection of intra- and extracapsular implant rupture. However, given its high costs, it is important that this technique is used sparingly. In this clinical lesson, we compare the sensitivity and specificity of mammography, ultrasound, CT and MRI for the detection of breast implant rupture. Based on two cases, a diagnostic approach is given in order to reduce health care costs. PMID:24252405

  10. Continuous EEG-fMRI in Pre-Surgical Evaluation of a Patient with Symptomatic Seizures: Bold Activation Linked to Interictal Epileptic Discharges Caused by Cavernoma.

    PubMed

    Avesani, M; Formaggio, E; Milanese, F; Baraldo, A; Gasparini, A; Cerini, R; Bongiovanni, L G; Pozzi Mucelli, R; Fiaschi, A; Manganotti, P

    2008-04-01

    We used continuous electroencephalography-functional magnetic resonance imaging (EEG-fMRI) to identify the linkage between the "epileptogenic" and the "irritative" area in a patient with symptomatic epilepsy (cavernoma, previously diagnosed and surgically treated), i.e. a patient with a well known "epileptogenic area", and to increase the possibility of a non invasive pre-surgical evaluation of drug-resistant epilepsies. A compatible MRI system was used (EEG with 29 scalp electrodes and two electrodes for ECG and EMG) and signals were recorded with a 1.5 Tesla MRI scanner. After the recording session and MRI artifact removal, EEG data were analyzed offline and used as paradigms in fMRI study. Activation (EEG sequences with interictal slow-spiked-wave activity) and rest (sequences of normal EEG) conditions were compared to identify the potential resulting focal increase in BOLD signal and to consider if this is spatially linked to the interictal focus used as a paradigm and to the lesion. We noted an increase in the BOLD signal in the left neocortical temporal region, laterally and posteriorly to the poro-encephalic cavity (residual of cavernoma previously removed), that is around the "epileptogenic area". In our study "epileptogenic" and "irritative" areas were connected with each other. Combined EEG-fMRI may become routine in clinical practice for a better identification of an irritative and lesional focus in patients with symptomatic drug-resistant epilepsy. PMID:24256824

  11. Heart MRI

    MedlinePlus

    ... severe kidney problems. People have been harmed in MRI machines when they did not remove metal objects from their clothes or when metal objects were left in the room by others. MRI is most often not recommended for traumatic injuries. ...

  12. MRI Scans

    MedlinePlus

    Magnetic resonance imaging (MRI) uses a large magnet and radio waves to look at organs and structures inside your body. Health care professionals use MRI scans to diagnose a variety of conditions, from torn ...

  13. Feasibility and limitations of bulk density assignment in MRI for head and neck IMRT treatment planning.

    PubMed

    Chin, Alexander L; Lin, Alexander; Anamalayil, Shibu; Teo, Boon-Keng Kevin

    2014-01-01

    Head and neck cancers centered at the base of skull are better visualized on MRI than on CT. The purpose of this investigation was to investigate the accuracy of bulk density assignment in head and neck intensity-modulated radiation therapy (IMRT) treatment plan optimization. Our study investigates dose calculation differences between density-assigned MRI and CT, and identifies potential limitations related to dental implants and MRI geometrical distortion in the framework of MRI-only-based treatment planning. Bulk density assignment was performed and applied onto MRI to generate three MRI image sets with increasing levels of heterogeneity for seven patients: 1) MRIW: all water-equivalent; 2) MRIW+B: included bone with density of 1.53 g/cm3; and 3) MRIW+B+A: included bone and air. Using identical planning and optimization parameters, MRI-based IMRT plans were generated and compared to corresponding, forward-calculated, CT-based plans on the basis of target coverage, isodose distributions, and dose-volume histograms (DVHs). Phantom studies were performed to assess the magnitude and spatial dependence of MRI geometrical distortion. MRIW-based dose calculations overestimated target coverage by 16.1%. Segmentation of bone reduced differences to within 2% of the coverage area on the CT-based plan. Further segmentation of air improved conformity near air-tissue interfaces. Dental artifacts caused substantial target coverage overestimation even on MRIW+B+A. Geometrical distortion was less than 1 mm in an imaging volume 20 × 20 × 20 cm3 around scanner isocenter, but up to 4 mm at 17 cm lateral to isocenter. Bulk density assignment in the framework of MRI-only IMRT head and neck treatment planning is a feasible method with certain limitations. Bone and teeth account for the majority of density heterogeneity effects. While soft tissue is well visualized on MRI compared to CT, dental implants may not be visible on MRI and must be identified by other means and assigned

  14. Cochlear Implants

    MedlinePlus

    ... electrodes are inserted. The electronic device at the base of the electrode array is then placed under ... FDA approval for implants The Food and Drug Administration (FDA) regulates cochlear implant devices for both adults ...

  15. Goserelin Implant

    MedlinePlus

    Goserelin implant is used in combination with radiation therapy and other medications to treat localized prostate cancer and is ... treatment of abnormal bleeding of the uterus. Goserelin implant is in a class of medications called gonadotropin- ...

  16. Cochlear Implants

    MedlinePlus

    A cochlear implant is a small, complex electronic device that can help to provide a sense of sound. People who are ... of-hearing can get help from them. The implant consists of two parts. One part sits on ...

  17. Carmustine Implant

    MedlinePlus

    Carmustine implant is used along with surgery and sometimes radiation therapy to treat malignant glioma (a certain type of ... Carmustine implant comes as a small wafer that is placed in the brain by a doctor during surgery to ...

  18. Breast Implants

    MedlinePlus

    ... Updated Safety Information (Consumer Article) FDA Provides Updated Safety Data on Silicone Gel-Filled Breast Implants (Press Announcement) [ARCHIVED] Breast Implant Guidance for Industry (2006) Post Approval Studies Webpage Freedom of Information ...

  19. Cochlear implant

    MedlinePlus

    ... antenna. This part of the implant receives the sound, converts the sound into an electrical signal, and sends it to ... implants allow deaf people to receive and process sounds and speech. However, these devices do not restore ...

  20. A Retrospective Analysis of Ruptured Breast Implants

    PubMed Central

    Baek, Woo Yeol; Lew, Dae Hyun

    2014-01-01

    Background Rupture is an important complication of breast implants. Before cohesive gel silicone implants, rupture rates of both saline and silicone breast implants were over 10%. Through an analysis of ruptured implants, we can determine the various factors related to ruptured implants. Methods We performed a retrospective review of 72 implants that were removed for implant rupture between 2005 and 2014 at a single institution. The following data were collected: type of implants (saline or silicone), duration of implantation, type of implant shell, degree of capsular contracture, associated symptoms, cause of rupture, diagnostic tools, and management. Results Forty-five Saline implants and 27 silicone implants were used. Rupture was diagnosed at a mean of 5.6 and 12 years after insertion of saline and silicone implants, respectively. There was no association between shell type and risk of rupture. Spontaneous was the most common reason for the rupture. Rupture management was implant change (39 case), microfat graft (2 case), removal only (14 case), and follow-up loss (17 case). Conclusions Saline implants have a shorter average duration of rupture, but diagnosis is easier and safer, leading to fewer complications. Previous-generation silicone implants required frequent follow-up observation, and it is recommended that they be changed to a cohesive gel implant before hidden rupture occurs. PMID:25396188

  1. The cause of 2S Diapason screw breakage after internal lumbar fixation: studies of the mechanical and material properties of the implant.

    PubMed

    Kolasa, P; Grabarczyk, J; Depczyk, T

    2002-08-30

    In the years 1994-99, unstable fractures of the lumbar spine were surgically treated with interbody fixation in the Department of Neurosurgery at the Nicholas Copernicus Voivodeship Specialized Hospital in Łódź, using stabilizers manufactured by various companies. Complications in the form of stabilizer breakage were observed in 1 case out of 22. The aim of the present study was to ascertain the reason why the Stryker 2S Diapason screws broke. Tests performed to measure the material and mechanical properties of the implant did not show any signs of material fatigue, nor were any material defects discovered. However, a scanning microscope investigation confirmed the hypothesis that the material had crumbled due to overload. This discovery led to the decision that screws would be mounted in the bodies of the vertebrae in a manner decreasing implant load. PMID:17679886

  2. Musculoskeletal MRI.

    PubMed

    Sage, Jaime E; Gavin, Patrick

    2016-05-01

    MRI has the unique ability to detect abnormal fluid content, and is therefore unparalleled in its role of detection, diagnosis, prognosis, treatment planning and follow-up evaluation of musculoskeletal disease. MRI in companion animals should be considered in the following circumstances: a definitive diagnosis cannot be made on radiographs; a patient is nonresponsive to medical or surgical therapy; prognostic information is desired; assessing surgical margins and traumatic and/or infectious joint and bone disease; ruling out subtle developmental or early aggressive bone lesions. The MRI features of common disorders affecting the shoulder, elbow, stifle, carpal, and tarsal joints are included in this chapter. PMID:26928749

  3. Pleomorphic structural imperfections caused by pulsed Bi-implantation in the bulk and thin-film morphologies of TiO2

    NASA Astrophysics Data System (ADS)

    Zatsepin, D. A.; Boukhvalov, D. W.; Kurmaev, E. Z.; Gavrilov, N. V.; Kim, S. S.; Zhidkov, I. S.

    2016-08-01

    The results of combined experimental and theoretical study of pleomorphic substitutional and clustering effects in Bi-doped TiO2 hosts (bulk and thin-film morphologies) are presented. Bi-doping of the bulk and thin-film titanium dioxide was made with help of pulsed ion-implantation (EBi+ = 30 keV, D = 1 × 1017 cm-2) without posterior tempering. The X-ray photoelectron spectroscopy (XPS) qualification (core-levels and valence bands) and Density-Functional Theory (DFT) calculations were employed in order to study the electronic structure of Bi-ion implanted TiO2 samples. According to XPS data obtained and DFT calculations, the Bi → Ti cation substitution occurs in Bi-implanted bulk TiO2, whereas in the thin-film morphology of TiO2:Bi the Bi-atoms have metal-like clusters segregation tendency. Based on the combined XPS and DFT considerations the possible reasons and mechanism for the observed effects are discussed. It is believed that established peculiarities of bismuth embedding into employed TiO2 hosts are mostly the sequence of pleomorphic origin for the formed "bismuth-oxygen" chemical bonding.

  4. Obstetric MRI.

    PubMed

    Levine, Deborah

    2006-07-01

    Ultrasound is the imaging modality of choice for pregnant patients. However, MRI is increasingly utilized in patients in whom the sonographic diagnosis is unclear. These include maternal conditions unique to pregnancy such as ectopic pregnancy, placenta accreta, and uterine dehiscence. MRI is also being increasingly utilized in the assessment of abdominopelvic pain in pregnancy, in particular in assessment for appendicitis. Fetal MRI is performed to assess central nervous system (CNS) abnormalities and patients who are considering fetal surgery for conditions such as neural tube defects, congenital diaphragmatic hernia, and masses that obstruct the airway. In the future, functional MRI and fetal volumetry may provide additional information that can aid in our care of complicated pregnancies. PMID:16736491

  5. Heart MRI

    MedlinePlus

    ... an imaging method that uses powerful magnets and radio waves to create pictures of the heart. It does ... radiation involved in MRI. The magnetic fields and radio waves used during the scan have not been shown ...

  6. Implantable Microimagers

    PubMed Central

    Ng, David C.; Tokuda, Takashi; Shiosaka, Sadao; Tano, Yasuo; Ohta, Jun

    2008-01-01

    Implantable devices such as cardiac pacemakers, drug-delivery systems, and defibrillators have had a tremendous impact on the quality of live for many disabled people. To date, many devices have been developed for implantation into various parts of the human body. In this paper, we focus on devices implanted in the head. In particular, we describe the technologies necessary to create implantable microimagers. Design, fabrication, and implementation issues are discussed vis-à-vis two examples of implantable microimagers; the retinal prosthesis and in vivo neuro-microimager. Testing of these devices in animals verify the use of the microimagers in the implanted state. We believe that further advancement of these devices will lead to the development of a new method for medical and scientific applications.

  7. High Productivity Implantation ''PARTIAL IMPLANT''

    SciTech Connect

    Hino, Masayoshi; Miyamoto, Naoki; Sakai, Shigeki; Matsumoto, Takao

    2008-11-03

    The patterned ion implantation 'PARTIAL IMPLANT' has been developed as a productivity improvement tool. The Partial Implant can form several different ion dose areas on the wafer surface by controlling the speed of wafer moving and the stepwise rotation of twist axis. The Partial Implant system contains two implant methods. One method is 'DIVIDE PARTIAL IMPLANT', that is aimed at reducing the consumption of the wafer. The Divide Partial Implant evenly divides dose area on one wafer surface into two or three different dose part. Any dose can be selected in each area. So the consumption of the wafer for experimental implantation can be reduced. The second method is 'RING PARTIAL IMPLANT' that is aimed at improving yield by correcting electrical characteristic of devices. The Ring Partial Implant can form concentric ion dose areas. The dose of wafer external area can be selected to be within plus or minus 30% of dose of wafer central area. So the electrical characteristic of devices can be corrected by controlling dose at edge side on the wafer.

  8. Immune activation during the implantation phase causes preeclampsia-like symptoms via the CD40-CD40 ligand pathway in pregnant mice.

    PubMed

    Matsubara, Keiichi; Matsubara, Yuko; Mori, Miki; Uchikura, Yuka; Hamada, Katsuyuki; Fujioka, Toru; Hashimoto, Hisashi; Matsumoto, Takashi

    2016-06-01

    The CD40 ligand (CD40L) is expressed by T cells and has a critical role in immune system regulation. Interventions targeting CD40L interactions following embryo implantation represent an approach to preventing preeclampsia (PE). To better understand the role of CD40L in PE, we developed a PE mouse model in which we examined how CD40L-induced immune activation affects embryo implantation. Blastocysts were incubated with CD40L-expressing adenovirus and then were transferred into the uterine horns of pseudopregnant ICR mice. Histology, biochemistry and flow cytometry experiments were performed to examine the characteristics of the mouse model. In early pregnancy, decidualization and spiral artery remodeling were reduced in CD40L-transfected mice (CD40L mice) compared with control mice. Hematoxylin-eosin (HE) staining revealed hemorrhaging and excess fibrin deposition at the labyrinth layer-junctional zone interface of the placenta, and PAS staining demonstrated prominent focal and segmental sclerosis with collapsed glomerular capillaries in the kidneys of the CD40L mice. Flow cytometry data showed that interferon-γ production derived from CD4(+) T cells was elevated in the splenic cells of CD40L mice. Blood pressure (measured by the tail-cuff method) and urine albumin concentrations were significantly increased in CD40L mice compared with control mice. Furthermore, the plasma concentrations of soluble Flt-1 and soluble endoglin were increased in CD40L mice, as occurs in human patients with PE. Thus, CD40L-induced T-helper cell type 1 differentiation during embryo implantation may have a critical role in the pathogenesis of a PE-like presentation in a novel mouse model of PE. PMID:26763855

  9. Poly implant breast implants (PIP) and the rupture risk in asymptomatic patients: a warning for greater clinician suspicion in assessment and counselling.

    PubMed

    Mylvaganam, Senthurun; Taylor, Rebecca; Thrush, Steven

    2013-01-01

    Poly implant prostheses (PIP) implants have raised concern due to the increased reporting of ruptures prompting a UK review in 2012 recommending that symptomatic patients only undergo magnetic resonance imaging (MRI) and explantation as necessary. Literature suggests two of three implant ruptures are asymptomatic. In this case, a 45-year-old woman with bilateral breast implants for cosmesis presented due to publicity of PIP implants. She was asymptomatic with no clinical signs suggestive of rupture. Due to patient intention for explanation of rupture, an MRI scan was undertaken which showed extensive silicone between the chest wall and lung bilaterally. The lung multidisciplinary team did not recommend removal of the lung silicone infiltrate. The implants were removed confirming rupture. Symptoms and signs cannot be relied upon to diagnose implant ruptures. Where patient concern exists with expressed intent for explantation if proven rupture, MRI assessment is a reliable tool where clinical uncertainty over rupture is present. PMID:24964409

  10. Poly implant breast implants (PIP) and the rupture risk in asymptomatic patients: a warning for greater clinician suspicion in assessment and counselling

    PubMed Central

    Mylvaganam, Senthurun; Taylor, Rebecca; Thrush, Steven

    2013-01-01

    Poly implant prostheses (PIP) implants have raised concern due to the increased reporting of ruptures prompting a UK review in 2012 recommending that symptomatic patients only undergo magnetic resonance imaging (MRI) and explantation as necessary. Literature suggests two of three implant ruptures are asymptomatic. In this case, a 45-year-old woman with bilateral breast implants for cosmesis presented due to publicity of PIP implants. She was asymptomatic with no clinical signs suggestive of rupture. Due to patient intention for explanation of rupture, an MRI scan was undertaken which showed extensive silicone between the chest wall and lung bilaterally. The lung multidisciplinary team did not recommend removal of the lung silicone infiltrate. The implants were removed confirming rupture. Symptoms and signs cannot be relied upon to diagnose implant ruptures. Where patient concern exists with expressed intent for explantation if proven rupture, MRI assessment is a reliable tool where clinical uncertainty over rupture is present. PMID:24964409

  11. Assessment of Electromagnetic Interference with Active Cardiovascular Implantable Electronic Devices (CIEDs) Caused by the Qi A13 Design Wireless Charging Board.

    PubMed

    Seckler, Tobias; Jagielski, Kai; Stunder, Dominik

    2015-06-01

    Electromagnetic interference is a concern for people wearing cardiovascular implantable electronic devices (CIEDs). The aim of this study was to assess the electromagnetic compatibility between CIEDs and the magnetic field of a common wireless charging technology. To do so the voltage induced in CIEDs by Qi A13 design magnetic fields were measured and compared with the performance limits set by ISO 14117. In order to carry this out a measuring circuit was developed which can be connected with unipolar or bipolar pacemaker leads. The measuring system was positioned at the four most common implantation sites in a torso phantom filled with physiological saline solution. The phantom was exposed by using Helmholtz coils from 5 µT to 27 µT with 111 kHz sine‑bursts or by using a Qi A13 design wireless charging board (Qi‑A13‑Board) in two operating modes "power transfer" and "pinging". With the Helmholtz coils the lowest magnetic flux density at which the performance limit was exceeded is 11 µT. With the Qi‑A13‑Board in power transfer mode 10.8% and in pinging mode 45.7% (2.2% at 10 cm distance) of the performance limit were reached at maximum. In neither of the scrutinized cases, did the voltage induced by the Qi‑A13‑Board exceed the performance limits. PMID:26024360

  12. Assessment of Electromagnetic Interference with Active Cardiovascular Implantable Electronic Devices (CIEDs) Caused by the Qi A13 Design Wireless Charging Board

    PubMed Central

    Seckler, Tobias; Jagielski, Kai; Stunder, Dominik

    2015-01-01

    Electromagnetic interference is a concern for people wearing cardiovascular implantable electronic devices (CIEDs). The aim of this study was to assess the electromagnetic compatibility between CIEDs and the magnetic field of a common wireless charging technology. To do so the voltage induced in CIEDs by Qi A13 design magnetic fields were measured and compared with the performance limits set by ISO 14117. In order to carry this out a measuring circuit was developed which can be connected with unipolar or bipolar pacemaker leads. The measuring system was positioned at the four most common implantation sites in a torso phantom filled with physiological saline solution. The phantom was exposed by using Helmholtz coils from 5 µT to 27 µT with 111 kHz sine-bursts or by using a Qi A13 design wireless charging board (Qi-A13-Board) in two operating modes “power transfer” and “pinging”. With the Helmholtz coils the lowest magnetic flux density at which the performance limit was exceeded is 11 µT. With the Qi-A13-Board in power transfer mode 10.8% and in pinging mode 45.7% (2.2% at 10 cm distance) of the performance limit were reached at maximum. In neither of the scrutinized cases, did the voltage induced by the Qi-A13-Board exceed the performance limits. PMID:26024360

  13. Portable MRI

    SciTech Connect

    Espy, Michelle A.

    2012-06-29

    This project proposes to: (1) provide the power of MRI to situations where it presently isn't available; (2) perform the engineering required to move from lab to a functional prototype; and (3) leverage significant existing infrastructure and capability in ultra-low field MRI. The reasons for doing this: (1) MRI is the most powerful tool for imaging soft-tissue (e.g. brain); (2) Billions don't have access due to cost or safety issues; (3) metal will heat/move in high magnetic fields; (4) Millions of cases of traumatic brain injury in US alone; (5) even more of non-traumatic brain injury; (6) (e.g. stroke, infection, chemical exposure); (7) Need for early diagnostic; (8) 'Signature' wound of recent conflicts; (9) 22% of injuries; (10) Implications for post-traumatic stress disorder; and (11) chronic traumatic encephalopathy.

  14. MRI driven magnetic microswimmers.

    PubMed

    Kósa, Gábor; Jakab, Péter; Székely, Gábor; Hata, Nobuhiko

    2012-02-01

    Capsule endoscopy is a promising technique for diagnosing diseases in the digestive system. Here we design and characterize a miniature swimming mechanism that uses the magnetic fields of the MRI for both propulsion and wireless powering of the capsule. Our method uses both the static and the radio frequency (RF) magnetic fields inherently available in MRI to generate a propulsive force. Our study focuses on the evaluation of the propulsive force for different swimming tails and experimental estimation of the parameters that influence its magnitude. We have found that an approximately 20 mm long, 5 mm wide swimming tail is capable of producing 0.21 mN propulsive force in water when driven by a 20 Hz signal providing 0.85 mW power and the tail located within the homogeneous field of a 3 T MRI scanner. We also analyze the parallel operation of the swimming mechanism and the scanner imaging. We characterize the size of artifacts caused by the propulsion system. We show that while the magnetic micro swimmer is propelling the capsule endoscope, the operator can locate the capsule on the image of an interventional scene without being obscured by significant artifacts. Although this swimming method does not scale down favorably, the high magnetic field of the MRI allows self propulsion speed on the order of several millimeter per second and can propel an endoscopic capsule in the stomach. PMID:22037673

  15. Allergic reaction to platinum in silicone breast implants.

    PubMed

    Arepalli, Sambasiva R; Bezabeh, Shewit; Brown, S Lori

    2002-01-01

    Platinum is used as a catalyst in the manufacture of silicone breast implants. Because platinum is recognized as a potent sensitizer in certain circumstances, some have expressed concern that women with silicone breast implants are exposed to platinum, which is causing allergic reactions. We searched the literature for information on the level of platinum in breast implants and reports of sensitization that clearly related to platinum in women with breast implants. We found no published report with convincing evidence that platinum causes allergic reactions in women with breast implants or that women with breast implants are any more likely to have allergic reactions than women without breast implants. PMID:12627791

  16. Goserelin Implant

    MedlinePlus

    ... which the type of tissue that lines the uterus [womb] grows in other areas of the body ... with the treatment of abnormal bleeding of the uterus. Goserelin implant is in a class of medications ...

  17. Ion Implantation

    NASA Astrophysics Data System (ADS)

    Langouche, G.; Yoshida, Y.

    In this tutorial we describe the basic principles of the ion implantation technique and we demonstrate that emission Mössbauer spectroscopy is an extremely powerful technique to investigate the atomic and electronic configuration around implanted atoms. The physics of dilute atoms in materials, the final lattice sites and their chemical state as well as diffusion phenomena can be studied. We focus on the latest developments of implantation Mössbauer spectroscopy, where three accelerator facilities, i.e., Hahn-Meitner Institute Berlin, ISOLDE-CERN and RIKEN, have intensively been used for materials research in in-beam and on-line Mössbauer experiments immediately after implantation of the nuclear probes.

  18. Dental Implants

    MedlinePlus Videos and Cool Tools

    ... facts so you can make an informed decision as to whether dental implants are right for your ... the jaw bone. It’s obviously not the same as the original connection , but functions just the same. ...

  19. Cochlear Implants

    MedlinePlus

    ... additional visits are needed for activating, adjusting, and programming the various electrodes that have been implanted. Also, ... to the center for checkups once the final programming is made to the speech processor. Both children ...

  20. Imaging for cochlear implants.

    PubMed

    Phelps, P D; Annis, J A; Robinson, P J

    1990-07-01

    Insertion of a sound amplification device into the round window niche (extracochlear implant) or into the coils of the cochlea (intracochlear implant) can give significant benefits to some carefully selected, severely deaf patients. Imaging has an essential role in selective and pre-operative assessment. Severe otosclerosis and post-meningitic labyrinthitis ossificans are common causes of deafness in these patients and can be demonstrated by computed tomography (CT). The most suitable side for operation can be assessed. We describe our experiences with 165 patients, 69 of whom were found suitable for implants. Thin (1 mm) section CT in axial and coronal planes is the best imaging investigation of the petrous temporal bones but the place of magnetic resonance scanning to confirm that the inner ear is fluid-filled and polytomography to show a multichannel implant in the cochlea is discussed. No implants were used for congenital deformities, but some observations are made of this type of structural deformity of the inner ear. PMID:2390686

  1. PET/MRI and PET/MRI/SISCOM coregistration in the presurgical evaluation of refractory focal epilepsy.

    PubMed

    Fernández, S; Donaire, A; Serès, E; Setoain, X; Bargalló, N; Falcón, C; Sanmartí, F; Maestro, I; Rumià, J; Pintor, L; Boget, T; Aparicio, J; Carreño, M

    2015-03-01

    We aimed to investigate the usefulness of coregistration of positron emission tomography (PET) and magnetic resonance imaging (MRI) findings (PET/MRI) and of coregistration of PET/MRI with subtraction ictal single-photon emission computed tomography (SPECT) coregistered to MRI (SISCOM) (PET/MRI/SISCOM) in localizing the potential epileptogenic zone in patients with drug-resistant epilepsy. We prospectively included 35 consecutive patients with refractory focal epilepsy whose presurgical evaluation included a PET study. Separately acquired PET and structural MRI images were coregistered for each patient. When possible, ictal SPECT and SISCOM were obtained and coregistered with PET/MRI. The potential location of the epileptogenic zone determined by neuroimaging was compared with the seizure onset zone determined by long-term video-EEG monitoring and with invasive EEG studies in patients who were implanted. Structural MRI showed no lesions in 15 patients. In these patients, PET/MRI coregistration showed a hypometabolic area in 12 (80%) patients that was concordant with seizure onset zone on EEG in 9. In 7 patients without MRI lesions, PET/MRI detected a hypometabolism that was undetected on PET alone. SISCOM, obtained in 25 patients, showed an area of hyperperfusion concordant with the seizure onset zone on EEG in 7 (58%) of the 12 of these patients who had normal MRI findings. SISCOM hyperperfusion was less extensive than PET hypometabolism. A total of 19 patients underwent surgery; 11 of these underwent invasive-EEG monitoring and the seizure onset zone was concordant with PET/MRI in all cases. PET/MRI/SISCOM coregistration, performed in 4 of these patients, was concordant in 3 (75%). After epilepsy surgery, 13 (68%) patients are seizure-free after a mean follow-up of 4.5 years. PET/MRI and PET/MRI/SISCOM coregistration are useful for determining the potential epileptogenic zone and thus for planning invasive EEG studies and surgery more precisely, especially in

  2. Battlefield MRI

    SciTech Connect

    Espy, Michelle

    2015-06-01

    Magnetic Resonance Imaging is the best method for non-invasive imaging of soft tissue anatomy, saving countless lives each year. It is regarded as the gold standard for diagnosis of mild to moderate traumatic brain injuries. Furthermore, conventional MRI relies on very high, fixed strength magnetic fields (> 1.5 T) with parts-per-million homogeneity, which requires very large and expensive magnets.

  3. Implant fractures: Rare but not exceptional.

    PubMed

    Sanivarapu, Sahitya; Moogla, Srinivas; Kuntcham, Rupa Sruthi; Kolaparthy, Lakshmi Kanth

    2016-01-01

    Fabrication of dentures aided with implants has become a preferred treatment option for rehabilitation of completely and partially edentulous patients when durability is concerned. Simulation to natural teeth in terms of esthetics and to a greater extent in function can be considered as key elements in the raise of implant dentistry worldwide. Despite its high success rate, therapy with osseointegrated dental implants is not free of complications. Implant failure can occur for other reasons, with implant fracture being one of the major reasons for late failure. Although the incidence of implant fractures may be low, it invariably effects the patient and also clinician. Thus, sound evidence based knowledge of cause of fracture is mandatory for that careful treatment that can reduce the incidence of fracture helping in a better treatment plan. The aim of this review is to enlighten the various causes of implant fracture. PMID:27041830

  4. Implant fractures: Rare but not exceptional

    PubMed Central

    Sanivarapu, Sahitya; Moogla, Srinivas; Kuntcham, Rupa Sruthi; Kolaparthy, Lakshmi Kanth

    2016-01-01

    Fabrication of dentures aided with implants has become a preferred treatment option for rehabilitation of completely and partially edentulous patients when durability is concerned. Simulation to natural teeth in terms of esthetics and to a greater extent in function can be considered as key elements in the raise of implant dentistry worldwide. Despite its high success rate, therapy with osseointegrated dental implants is not free of complications. Implant failure can occur for other reasons, with implant fracture being one of the major reasons for late failure. Although the incidence of implant fractures may be low, it invariably effects the patient and also clinician. Thus, sound evidence based knowledge of cause of fracture is mandatory for that careful treatment that can reduce the incidence of fracture helping in a better treatment plan. The aim of this review is to enlighten the various causes of implant fracture. PMID:27041830

  5. [Implant fracture: a complication of treatment with dental implants--review of the literature].

    PubMed

    Tagger-Green, N; Horwitz, J; Machtei, E E; Peled, M

    2002-10-01

    Dental implants are a functional and esthetic solution to partial and total edentulism. The initial success rate of this treatment modality is 90-95%. But, that treatment modality is not free of complications. One of the rare complications yet, with severe clinical results is fracture of dental implants. The current literature review presents the various causative factors that may lead to implant fracture. Implant failures may be sorted into groups by the timing of their appearance, or by the origin of failure. Fractures belong to the group of late complications, caused by a biomechanical overload. Overload may be caused by inappropriate seat of the superstructure, in-line arrangement of the implants, leverage, heavy occlusal forces (bruxing, clenching), location of the implant and the size of the implant or metal fatigue. Good clinical examinations and correct treatment plans may reduce the risk of implant fracture. PMID:12510252

  6. MR imaging of ectopic pregnancy with an emphasis on unusual implantation sites.

    PubMed

    Köroğlu, Mert; Kayhan, Arda; Soylu, Fatma Nur; Erol, Bekir; Schmid-Tannwald, Christine; Gürses, Cemil; Karademir, İbrahim; Ernst, Randy; Yousuf, Ambereen; Oto, Aytekin

    2013-02-01

    Ectopic pregnancy (EP) is a life-threatening condition and remains the leading cause of death in the first trimester of pregnancy, although the mortality rate has significantly decreased over the past few decades because of earlier diagnoses and great improvements in treatment. EP is most commonly located in the ampullary portion of the fallopian tube and rarely in unusual sites such as the interstitium, cervix, cesarean scar, anomalous rudimentary horn of the uterus and peritoneal abdominal cavity. MRI may confirm or give additional information to ultrasonography, which is the most user-dependent imaging modality. Magnetic resonance imaging can accurately localize the site of abnormal implantation. It could be helpful for EP patient treatment by distinguishing the ruptured and unruptured cases before methotrexate treatment. MRI is quite sensitive to blood and can identify the hemorrhage phase. PMID:23132557

  7. Injury to the coronary arteries and related structures by implantation of cardiac implantable electronic devices.

    PubMed

    Pang, Benjamin J; Barold, S Serge; Mond, Harry G

    2015-04-01

    Damage to the coronary arteries and related structures from pacemaker and implantable cardioverter-defibrillator lead implantation is a rarely reported complication that can lead to myocardial infarction and pericardial tamponade that may occur acutely or even years later. We summarize the reported cases of injury to coronary arteries and related structures and review the causes of troponin elevation in the setting of cardiac implantable electronic device implantation. PMID:25564549

  8. MRI compatible optrodes for simultaneous LFP and optogenetic fMRI investigation of seizure-like afterdischarges.

    PubMed

    Duffy, Ben A; Choy, ManKin; Chuapoco, Miguel R; Madsen, Michael; Lee, Jin Hyung

    2015-12-01

    In preclinical studies, implanted electrodes can cause severe degradation of MRI images and hence are seldom used for chronic studies employing functional magnetic resonance imaging. In this study, we developed carbon fiber optrodes (optical fiber and electrode hybrid devices), which can be utilised in chronic longitudinal studies aiming to take advantage of emerging optogenetic technologies, and compared them with the more widely used tungsten optrodes. We find that optrodes constructed using small diameter (~130 μm) carbon fiber electrodes cause significantly reduced artifact on functional MRI images compared to those made with 50 μm diameter tungsten wire and at the same time the carbon electrodes have lower impedance, which leads to higher quality LFP recordings. In order to validate this approach, we use these devices to study optogenetically-induced seizure-like afterdischarges in rats sedated with dexmedetomidine and compare these to sub (seizure) threshold stimulations in the same animals. The results indicate that seizure-like afterdischarges involve several extrahippocampal brain regions that are not recruited by subthreshold optogenetic stimulation of the hippocampus at 20 Hz. Subthreshold stimulation led to activation of the entire ipsilateral hippocampus and septum, whereas afterdischarges additionally produced activations in the contralateral hippocampal formation, neocortex, cerebellum, nucleus accumbens, and thalamus. Although we demonstrate just one application, given the ease of fabrication, we anticipate that carbon fiber optrodes could be utilised in a variety of studies that could benefit from longitudinal optogenetic functional magnetic resonance imaging. PMID:26208873

  9. MRI analyses show that kinesio taping affects much more than just the targeted superficial tissues and causes heterogeneous deformations within the whole limb.

    PubMed

    Pamuk, Uluç; Yucesoy, Can A

    2015-12-16

    Kinesio taping (KT) is widely used in the treatment of sports injuries and various neuro-musculoskeletal disorders. However, it is considered as selectively effective on targeted tissues and its mechanical effects have not been quantified objectively. Ascribed to continuity of muscular and connective tissues, mechanical loading imposed can have widespread heterogeneous effects. The aim was to characterize the mechanical effects of KT objectively and to test the hypotheses that KT causes acutely, local deformations not necessarily (I) in agreement with tape adhering direction and (II) limited to the directly targeted tissues. High-resolution 3D magnetic resonance image sets were acquired in healthy human subjects (n=5) prior to and acutely after KT application over the skin along m. tibialis anterior (TA). Hip, knee and ankle angles were kept constant. Demons image registration algorithm was used to calculate local tissue deformations within the lower leg, in vivo. Mean peak tissue strains were significantly higher than strain artifacts. Only KT-to-TA region in part shows local deformations in agreement with tape adhering direction whereas, superficial skin, the rest of KT-to-TA and TA regions show deformations (up to 51.5% length change) in other directions. Non-targeted tissues also show sizable heterogeneous deformations, but in smaller amplitudes. Inter-subject variability is notable. Magnetic resonance imaging analyses allow for a detailed assessment of local tissue deformation occurring acutely after KT application. The findings confirm our hypotheses and characterize how KT affects the underlying tissues, both immediately targeted and distant. This allows revealing mechanisms that can affect clinical outcomes of KT objectively. PMID:26556717

  10. Application of 23Na MRI to Monitor Chemotherapeutic Response in RIF-1 Tumors1

    PubMed Central

    Babsky, Andriy M; Hekmatyar, Shahryar K; Zhang, Hong; Solomon, James L; Bansal, Navin

    2005-01-01

    Abstract Effects of an alkylating anticancer drug, cyclophosphamide (Cp), on 23Na signal intensity (23Na SI) and water apparent diffusion coefficient (ADC) were examined in subcutaneously-implanted radiation-induced fibrosarcoma (RIF-1) tumors by in vivo 23Na and 1H magnetic resonance imaging (MRI). MRI experiments were performed on untreated control (n = 5) and Cp-treated (n = 6) C3H mice, once before Cp injection (300 mg/kg) then daily for 3 days after treatment. Tumor volumes were significantly lower in treated animals 2 and 3 days posttreatment. At the same time points, MRI experiments showed an increase in both 23Na SI and water ADC in treated tumors, whereas control tumors did not show any significant changes. The correlation between 23Na SI and water ADC changes was dramatically increased in the Cp-treated group, suggesting that the observed increases in 23Na SI and water ADC were caused by the same mechanism. Histologic sections showed decreased cell density in the regions of increased 23Na and water ADC SI. Destructive chemical analysis showed that Cp treatment increased the relative extracellular space and tumor [Na+]. We conclude that the changes in water ADC and 23Na SI were largely due to an increase in extracellular space. 23Na MRI and 1H water ADC measurements may provide valuable noninvasive techniques for monitoring chemotherapeutic responses. PMID:16026645

  11. Leg MRI scan

    MedlinePlus

    ... imaging - leg; Magnetic resonance imaging - lower extremity; MRI - ankle; Magnetic resonance imaging - ankle; MRI - femur; MRI - leg ... or bone scan Birth defects of the leg, ankle, or foot Bone pain and fever Broken bone ...

  12. MRI Safety during Pregnancy

    MedlinePlus

    ... during the exam? Contrast material MRI during pregnancy Magnetic resonance imaging (MRI) If you are pregnant and your doctor wants to perform a magnetic resonance imaging (MRI) exam, there is a possibility that your ...

  13. Changes in the surface of bone and acid-etched and sandblasted implants following implantation and removal

    PubMed Central

    Eroglu, Cennet Neslihan; Ertugrul, Abdullah Seckin; Eskitascioglu, Murat; Eskitascioglu, Gurcan

    2016-01-01

    Objective: The aim of this study was to determine whether there are any changes in the surface of bone or implant structures following the removal of a screwed dental implant. Materials and Methods: For this, six individual samples of acid-etched and sandblasted implants from three different manufacturers’ implant systems were used. They were screwed in a D1 bovine bone, and they were removed after primary stabilization. The bone and implant surfaces are evaluated with scanning electron microscope. Results: Through examination of the surfaces of the bone prior to implantation and of the used and unused implant surfaces, it was found that inhomogeneity in the implant surface can cause microcracking in the bone. Conclusions: This is attributed to the stress induced during the implantation of self-tapping implants and suggests that a tap drill may be required in some instances to protect the implant surface. PMID:27011744

  14. Hip Implant Modified To Increase Probability Of Retention

    NASA Technical Reports Server (NTRS)

    Canabal, Francisco, III

    1995-01-01

    Modification in design of hip implant proposed to increase likelihood of retention of implant in femur after hip-repair surgery. Decreases likelihood of patient distress and expense associated with repetition of surgery after failed implant procedure. Intended to provide more favorable flow of cement used to bind implant in proximal extreme end of femur, reducing structural flaws causing early failure of implant/femur joint.

  15. Cochlear Implants

    MedlinePlus

    ... outside of the body, behind the ear. A second part is surgically placed under the skin. An implant does not restore normal hearing. It can help a person understand speech. Children and adults can benefit from them. National Institute on Deafness and Other Communication Disorders

  16. Cochlear implant

    MedlinePlus

    ... are sent along the auditory nerve to the brain. A deaf person does not have a functioning inner ear. A cochlear implant tries to replace the function of the inner ear by ... signals to the brain. Sound is picked up by a microphone worn ...

  17. MRI Findings in Neuroferritinopathy

    PubMed Central

    Ohta, Emiko; Takiyama, Yoshihisa

    2012-01-01

    Neuroferritinopathy is a neurodegenerative disease which demonstrates brain iron accumulation caused by the mutations in the ferritin light chain gene. On brain MRI in neuroferritinopathy, iron deposits are observed as low-intensity areas on T2WI and as signal loss on T2∗WI. On T2WI, hyperintense abnormalities reflecting tissue edema and gliosis are also seen. Another characteristic finding is the presence of symmetrical cystic changes in the basal ganglia, which are seen in the advanced stages of this disorder. Atrophy is sometimes noted in the cerebellar and cerebral cortices. The variety in the MRI findings is specific to neuroferritinopathy. Based on observations of an excessive iron content in patients with chronic neurologic disorders, such as Parkinson disease and Alzheimer disease, the presence of excess iron is therefore recognized as a major risk factor for neurodegenerative diseases. The future development of multimodal and advanced MRI techniques is thus expected to play an important role in accurately measuring the brain iron content and thereby further elucidating the neurodegenerative process. PMID:21808735

  18. An Assessment of Hazards Caused by Electromagnetic Interaction on Humans Present near Short-Wave Physiotherapeutic Devices of Various Types Including Hazards for Users of Electronic Active Implantable Medical Devices (AIMD)

    PubMed Central

    Gryz, Krzysztof

    2013-01-01

    Leakage of electromagnetic fields (EMF) from short-wave radiofrequency physiotherapeutic diathermies (SWDs) may cause health and safety hazards affecting unintentionally exposed workers (W) or general public (GP) members (assisting patient exposed during treatment or presenting there for other reasons). Increasing use of electronic active implantable medical devices (AIMDs), by patients, attendants, and workers, needs attention because dysfunctions of these devices may be caused by electromagnetic interactions. EMF emitted by 12 SWDs (with capacitive or inductive applicators) were assessed following international guidelines on protection against EMF exposure (International Commission on Nonionizing Radiation Protection for GP and W, new European directive 2013/35/EU for W, European Recommendation for GP, and European Standard EN 50527-1 for AIMD users). Direct EMF hazards for humans near inductive applicators were identified at a distance not exceeding 45 cm for W or 62 cm for GP, but for AIMD users up to 90 cm (twice longer than that for W and 50% longer than that for GP because EMF is pulsed modulated). Near capacitive applicators emitting continuous wave, the corresponding distances were: 120 cm for W or 150 cm for both—GP or AIMD users. This assessment does not cover patients who undergo SWD treatment (but it is usually recommended for AIMD users to be careful with EMF treatment). PMID:24089662

  19. An assessment of hazards caused by electromagnetic interaction on humans present near short-wave physiotherapeutic devices of various types including hazards for users of electronic active implantable medical devices (AIMD).

    PubMed

    Karpowicz, Jolanta; Gryz, Krzysztof

    2013-01-01

    Leakage of electromagnetic fields (EMF) from short-wave radiofrequency physiotherapeutic diathermies (SWDs) may cause health and safety hazards affecting unintentionally exposed workers (W) or general public (GP) members (assisting patient exposed during treatment or presenting there for other reasons). Increasing use of electronic active implantable medical devices (AIMDs), by patients, attendants, and workers, needs attention because dysfunctions of these devices may be caused by electromagnetic interactions. EMF emitted by 12 SWDs (with capacitive or inductive applicators) were assessed following international guidelines on protection against EMF exposure (International Commission on Nonionizing Radiation Protection for GP and W, new European directive 2013/35/EU for W, European Recommendation for GP, and European Standard EN 50527-1 for AIMD users). Direct EMF hazards for humans near inductive applicators were identified at a distance not exceeding 45 cm for W or 62 cm for GP, but for AIMD users up to 90 cm (twice longer than that for W and 50% longer than that for GP because EMF is pulsed modulated). Near capacitive applicators emitting continuous wave, the corresponding distances were: 120 cm for W or 150 cm for both-GP or AIMD users. This assessment does not cover patients who undergo SWD treatment (but it is usually recommended for AIMD users to be careful with EMF treatment). PMID:24089662

  20. Complications of Poly Implant Prothèse breast implants: the current discussion.

    PubMed

    Kolios, Leila; Hirche, Christoph; Spiethoff, Alexander; Daigeler, Adrien; Lehnhardt, Marcus

    2013-03-01

    Against the background of the current discussion about Poly Implant Prothèse (PIP, Seyne-sur-mer, France) breast implants, we want to present a case demonstrating the complications such as implant rupture, silicone dissemination and level III silicone lymphadenopathy. A 29-year-old woman with cosmetic breast augmentation with PIP implants 5 years previously showed a sensitive swelling in her right axilla and neck region. All tests to detect an infectious or lymphomatous lymphadenopathy were negative. After ultrasound and MRI, rupture of the right implant was assumed and multiple pathologically enlarged lymph nodes up to supraclavicular region were shown. An excision biopsy of one axillary lymph node was performed; the histological examination detected a strong silicone lymphadenopathy. Surgical removal of both implants as well as capsulectomy was performed and 14 axillary lymph nodes up to level II were resected. Histologic evaluation confirmed the previous results. Our case underlines the actual discussion concerning increased rupture rate and massive silicone lymphadenopathy by PIP implants. The Agence Francaise de Sécurité Sanitaire des Produits de Santé (AFSSAPS) recommends clinical and ultrasound examination every 6 months for women with PIP implants. Any rupture, suspected rupture or leakage of prosthesis should lead to its explantation as well as that of the contralateral implant. In cases of unusual signs of inflammation, histological and immunohistochemical samples are to be taken. PMID:23480085

  1. Dual-Energy CT for Evaluation of Intra- and Extracapsular Silicone Implant Rupture

    PubMed Central

    Glazebrook, Katrina N.; Leng, Shuai; Jacobson, Steven R.; McCollough, Cynthia M.

    2016-01-01

    Silicone implants are commonly used for both breast augmentation and breast reconstruction. With aging of the implant, the silicone envelope may become weak or may rupture. The technique of choice for evaluation of implant integrity is breast MRI; however this may be contraindicated in some patients or the cost may be prohibitive. Dual-energy CT allows determination of density and atomic number of tissue and can provide material composition information. We present a case of extracapsular implant rupture with MRI and dual-energy CT imaging and surgical correlation. PMID:26942031

  2. Dual-Energy CT for Evaluation of Intra- and Extracapsular Silicone Implant Rupture.

    PubMed

    Glazebrook, Katrina N; Leng, Shuai; Jacobson, Steven R; McCollough, Cynthia M

    2016-01-01

    Silicone implants are commonly used for both breast augmentation and breast reconstruction. With aging of the implant, the silicone envelope may become weak or may rupture. The technique of choice for evaluation of implant integrity is breast MRI; however this may be contraindicated in some patients or the cost may be prohibitive. Dual-energy CT allows determination of density and atomic number of tissue and can provide material composition information. We present a case of extracapsular implant rupture with MRI and dual-energy CT imaging and surgical correlation. PMID:26942031

  3. [Metal implant sensitivity: clinical and histological presentation].

    PubMed

    Hartmann, D; Letulé, V; Schneider, J J; Flaig, M J

    2016-05-01

    Metal implant sensitivity (intolerance) can cause pain, reduced mobility, loosening of the implant and skin rashes. Knowledge of differential diagnoses, histology and appropriate diagnostics are essential for proper diagnosis. To outline typical clinical signs and histology in metal-implant-associated skin lesions we present three exemplary patients from our implant allergy outpatient department and give an overview of the current literature regarding metal implant sensitivity. In patients with a negative patch test the lymphocyte transformation test may reveal metal sensitization. Even "pure" titanium alloys may contain traces of nickel. The histology of implant-associated skin reactions goes from teleangiectatic postimplantation erythema to eczema and vasculitis. Based on the synopsis of history, clinical picture, allergological testing and histology, metal implant sensitivity can be diagnosed more precisely. PMID:27090521

  4. MRI-compatible micromanipulator; design and implementation and MRI-compatibility tests.

    PubMed

    Koseki, Yoshihiko; Tanikawa, Tamio; Chinzei, Kiyoyuki

    2007-01-01

    In this paper, we present a magnetic resonance imaging (MRI)-compatible micromanipulator, which can be employed to provide medical and biological scientists with the ability to concurrently manipulate and observe micron-scale objects inside an MRI gantry. The micromanipulator formed a two-finger micro hand, and it could handle a micron-scale object using a chopstick motion. For performing operations inside the MRI gantry in a manner such that the MRI is not disturbed, the system was designed to be nonmagnetic and electromagnetically compatible with the MRI. The micro-manipulator was implemented with piezoelectric transducers (PZT) as actuators for micro-motion, strain gauges as sensors for closed-loop control, and a flexure parallel mechanism made of acrylic plastic. Its compatibility with a 2-Tesla MRI was preliminarily tested by checking if the MRI obtained with the micromanipulator were similar to those obtained without the micromanipulator. The tests concluded that the micromanipulator caused no distortion but small artifacts on the MRI. The signal-to-noise ratio (SNR) of the MRI significantly deteriorated mainly due to the wiring of the micromanipulator. The MRI caused noise of the order of ones of volts in the strain amplifier. PMID:18001990

  5. Magnetic Resonance Imaging (MRI)

    MedlinePlus

    ... How Can I Help a Friend Who Cuts? Magnetic Resonance Imaging (MRI) KidsHealth > For Teens > Magnetic Resonance Imaging (MRI) Print A A A Text Size What's ... Exam Safety Getting Your Results What Is MRI? Magnetic resonance imaging (MRI) is a type of safe, painless testing ...

  6. Stability, Visibility, and Histologic Analysis of a New Implanted Fiducial for Use as a Kilovoltage Radiographic or Radioactive Marker for Patient Positioning and Monitoring in Radiotherapy

    SciTech Connect

    Neustadter, David; Tune, Michal; Zaretsky, Asaph; Shofti, Rona; Kushnir, Arnon; Harel, Tami; Carmi-Yinon, Dafna; Corn, Ben M.S.

    2010-07-15

    Purpose: To analyze the stability, visibility, and histology of a novel implantable soft-tissue marker (nonradioactive and radioactive) implanted in dog prostate and rabbit liver. Methods and Materials: A total of 34 nonradioactive and 35 radioactive markers were implanted in 1 dog and 16 rabbits. Stability was assessed by measuring intermarker distance (IMD) variation relative to IMDs at implantation. The IMDs were measured weekly for 4 months in the dog and biweekly for 2-4 weeks in the rabbits. Ultrasound and X-ray imaging were performed on all subjects. Computed tomography and MRI were performed on the dog. Histologic analysis was performed on the rabbits after 2 or 4 months. Results: A total of 139 measurements had a mean ({+-} SD) absolute IMD variation of 1.1 {+-} 1.1 mm. These IMD variations are consistent with those reported in the literature as due to random organ deformation. The markers were visible, identifiable, and induced minimal or no image artifacts in all tested imaging modalities. Histologic analysis revealed that all pathologic changes were highly localized and not expected to be clinically significant. Conclusions: The markers were stable from the time of implantation. The markers were found to be compatible with all common medical imaging modalities. The markers caused no significant histologic effects. With respect to marker stability, visibility, and histologic analysis these implanted fiducials are appropriate for soft-tissue target positioning in radiotherapy.

  7. Biomedical Imaging in Implantable Drug Delivery Systems

    PubMed Central

    Zhou, Haoyan; Hernandez, Christopher; Goss, Monika; Gawlik, Anna; Exner, Agata A.

    2015-01-01

    Implantable drug delivery systems (DDS) provide a platform for sustained release of therapeutic agents over a period of weeks to months and sometimes years. Such strategies are typically used clinically to increase patient compliance by replacing frequent administration of drugs such as contraceptives and hormones to maintain plasma concentration within the therapeutic window. Implantable or injectable systems have also been investigated as a means of local drug administration which favors high drug concentration at a site of interest, such as a tumor, while reducing systemic drug exposure to minimize unwanted side effects. Significant advances in the field of local DDS have led to increasingly sophisticated technology with new challenges including quantification of local and systemic pharmacokinetics and implant-body interactions. Because many of these sought-after parameters are highly dependent on the tissue properties at the implantation site, and rarely represented adequately with in vitro models, new nondestructive techniques that can be used to study implants in situ are highly desirable. Versatile imaging tools can meet this need and provide quantitative data on morphological and functional aspects of implantable systems. The focus of this review article is an overview of current biomedical imaging techniques, including magnetic resonance imaging (MRI), ultrasound imaging, optical imaging, X-ray and computed tomography (CT), and their application in evaluation of implantable DDS. PMID:25418857

  8. Advances in implantable cardioverter defibrillator therapy.

    PubMed

    Rickard, John; Wilkoff, Bruce L

    2016-03-01

    Since the first implant in 1980, implantable cardioverter defibrillator (ICD) technology has progressed rapidly. Modern ICD's have hundreds of programmable options with the general goal of preventing inappropriate shocks and providing shocks for truly life threatening symptomatic ventricular arrhythmias. New studies on ICD programming have shown the benefits of prolonged detection intervals in reaching this goal. Anti-tachycardia pacing (ATP) therapy has become an important adjunct to defibrillator shocks. Remote monitoring technologies have surfaced which have been shown to identify arrhythmias and problems with the device in an expedient fashion. The subcutaneous ICD offers the advantage of avoiding intravascular leads and their inherent risks. Lastly, the current understanding of the effects of MRI in ICD patients has advanced creating new opportunities to provide MRI safely to such patients. PMID:26653411

  9. The Clinical Implications of Poly Implant Prothèse Breast Implants: An Overview

    PubMed Central

    Wazir, Umar; Kasem, Abdul

    2015-01-01

    Mammary implants marketed by Poly Implant Prothèse (PIP) were found to contain industrial grade silicone and this caused heightened anxiety and extensive publicity regarding their safety in humans. These implants were used in a large number of patients worldwide for augmentation or breast reconstruction. We reviewed articles identified by searches of Medline, PubMed, Embase, and Google Scholar databases up to May 2014 using the terms: "PIP", "Poly Implant Prothèse", "breast implants" and "augmentation mammoplasty" "siloxanes" or "silicone". In addition the websites of regulating bodies in Europe, USA, and Australia were searched for reports related to PIP mammary implants. PIP mammary implants are more likely to rupture than other implants and can cause adverse effects in the short to the medium term related to the symptoms of rupture such as pain, lumps in the breast and axilla and anxiety. Based on peer-reviewed published studies we have calculated an overall rupture rate of 14.5% (383/2,635) for PIP implants. However, there is no evidence that PIP implant rupture causes long-term adverse health effects in humans so far. Silicone lymphadenopathy represents a foreign body reaction and should be treated conservatively. The long-term adverse effects usually arise from inappropriate extensive surgery, such as axillary lymph node dissection or extensive resection of breast tissue due to silicone leakage. PMID:25606483

  10. The clinical implications of poly implant prothèse breast implants: an overview.

    PubMed

    Wazir, Umar; Kasem, Abdul; Mokbel, Kefah

    2015-01-01

    Mammary implants marketed by Poly Implant Prothèse (PIP) were found to contain industrial grade silicone and this caused heightened anxiety and extensive publicity regarding their safety in humans. These implants were used in a large number of patients worldwide for augmentation or breast reconstruction. We reviewed articles identified by searches of Medline, PubMed, Embase, and Google Scholar databases up to May 2014 using the terms: "PIP", "Poly Implant Prothèse", "breast implants" and "augmentation mammoplasty" "siloxanes" or "silicone". In addition the websites of regulating bodies in Europe, USA, and Australia were searched for reports related to PIP mammary implants. PIP mammary implants are more likely to rupture than other implants and can cause adverse effects in the short to the medium term related to the symptoms of rupture such as pain, lumps in the breast and axilla and anxiety. Based on peer-reviewed published studies we have calculated an overall rupture rate of 14.5% (383/2,635) for PIP implants. However, there is no evidence that PIP implant rupture causes long-term adverse health effects in humans so far. Silicone lymphadenopathy represents a foreign body reaction and should be treated conservatively. The long-term adverse effects usually arise from inappropriate extensive surgery, such as axillary lymph node dissection or extensive resection of breast tissue due to silicone leakage. PMID:25606483

  11. Research on Blastocyst Implantation Essential Factors (BIEFs).

    PubMed

    Yoshinaga, Koji

    2010-06-01

    Blastocyst implantation is a process of interaction between embryo and the uterus. To understand this process, this review tries to summarize what blastocyst implantation essential factors (BIEFs) play what roles, as well as where in the uterus and at what stage of implantation process. Addition of more new data to this kind of compilation of information will help the development of diagnosis and treatment of infertility caused by implantation failure. The major, important cells of the endometrial cells that interact with invading blastocyst (trophoblast) are luminal epithelial cells, stromal cells (decidual cells) and resident immune cells. BIEFs regulate these cells to successfully maintain pregnancy. PMID:20455874

  12. PIP breast implants: rupture rate and correlation with breast cancer

    PubMed Central

    MOSCHETTA, M.; TELEGRAFO, M.; CORNACCHIA, I.; VINCENTI, L.; RANIERI, V.; CIRILLI, A.; RELLA, L.; IANORA, A.A. STABILE; ANGELELLI, G.

    2014-01-01

    Aim To evaluate the incidence of Poly Implant Prosthése (PIP) rupture as assessed by magnetic resonance imaging (MRI), the prevalence of the detected signs and the potential correlation with breast carcinoma. Patients and methods 67 patients with silicone breast implants and clinical indications for breast MRI were evaluated for a total of 125 implants: 40 (32%) PIP in 21 patients and 85 non-PIP in 46 patients (68%), the latest considered as control group. A 1.5-T MR imaging device was used in order to assess implant integrity with dedicated sequences and in 6 cases a dynamic study was performed for characterizing breast lesions. Two radiologists with more than 5 years’ experience in the field of MRI evaluated in consensus all MR images searching for the presence of clear signs of intra or extra-capsular implant rupture. Results 20/40 (50%) PIP implants presented signs of intra-capsular rupture: linguine sign in 20 cases (100%), tear-drop sign in 6 (30%). In 12/20 cases (60%), MRI signs of extra-capsular rupture were detected. In the control group, an intra-capsular rupture was diagnosed in 12/85 cases (14%) associated with extra-capsular one in 5/12 cases (42%). Among the six cases with suspected breast lesions, in 2/21 patients with PIP implants (10%) a breast carcinoma was diagnosed (mucinous carcinoma, n=1; invasive ductal carcinoma, n=1). In 4/46 patients (9%) with non-PIP implants, an invasive ductal carcinoma was diagnosed. Conclusion The rupture rate of PIP breast implants is significantly higher than non-PIP (50% vs 14%). MRI represents the most accurate imaging tool for evaluating breast prostheses and the linguine sign is the most common MRI sign to be searched. The incidence of breast carcinoma does not significantly differ between the PIP and non-PIP implants and a direct correlation with breast cancer can not been demonstrated. PMID:25644728

  13. Magnetic resonance imaging investigation of the bone conduction implant – a pilot study at 1.5 Tesla

    PubMed Central

    Jansson, Karl-Johan Fredén; Håkansson, Bo; Reinfeldt, Sabine; Rigato, Cristina; Eeg-Olofsson, Måns

    2015-01-01

    Purpose The objective of this pilot study was to investigate if an active bone conduction implant (BCI) used in an ongoing clinical study withstands magnetic resonance imaging (MRI) of 1.5 Tesla. In particular, the MRI effects on maximum power output (MPO), total harmonic distortion (THD), and demagnetization were investigated. Implant activation and image artifacts were also evaluated. Methods and materials One implant was placed on the head of a test person at the position corresponding to the normal position of an implanted BCI and applied with a static pressure using a bandage and scanned in a 1.5 Tesla MRI camera. Scanning was performed both with and without the implant, in three orthogonal planes, and for one spin-echo and one gradient-echo pulse sequence. Implant functionality was verified in-between the scans using an audio processor programmed to generate a sequence of tones when attached to the implant. Objective verification was also carried out by measuring MPO and THD on a skull simulator as well as retention force, before and after MRI. Results It was found that the exposure of 1.5 Tesla MRI only had a minor effect on the MPO, ie, it decreased over all frequencies with an average of 1.1±2.1 dB. The THD remained unchanged above 300 Hz and was increased only at lower frequencies. The retention magnet was demagnetized by 5%. The maximum image artifacts reached a distance of 9 and 10 cm from the implant in the coronal plane for the spin-echo and the gradient-echo sequence, respectively. The test person reported no MRI induced sound from the implant. Conclusion This pilot study indicates that the present BCI may withstand 1.5 Tesla MRI with only minor effects on its performance. No MRI induced sound was reported, but the head image was highly distorted near the implant. PMID:26604836

  14. Therapy using implanted organic bioelectronics

    PubMed Central

    Jonsson, Amanda; Song, Zhiyang; Nilsson, David; Meyerson, Björn A.; Simon, Daniel T.; Linderoth, Bengt; Berggren, Magnus

    2015-01-01

    Many drugs provide their therapeutic action only at specific sites in the body, but are administered in ways that cause the drug’s spread throughout the organism. This can lead to serious side effects. Local delivery from an implanted device may avoid these issues, especially if the delivery rate can be tuned according to the need of the patient. We turned to electronically and ionically conducting polymers to design a device that could be implanted and used for local electrically controlled delivery of therapeutics. The conducting polymers in our device allow electronic pulses to be transduced into biological signals, in the form of ionic and molecular fluxes, which provide a way of interfacing biology with electronics. Devices based on conducting polymers and polyelectrolytes have been demonstrated in controlled substance delivery to neural tissue, biosensing, and neural recording and stimulation. While providing proof of principle of bioelectronic integration, such demonstrations have been performed in vitro or in anesthetized animals. Here, we demonstrate the efficacy of an implantable organic electronic delivery device for the treatment of neuropathic pain in an animal model. Devices were implanted onto the spinal cord of rats, and 2 days after implantation, local delivery of the inhibitory neurotransmitter γ-aminobutyric acid (GABA) was initiated. Highly localized delivery resulted in a significant decrease in pain response with low dosage and no observable side effects. This demonstration of organic bioelectronics-based therapy in awake animals illustrates a viable alternative to existing pain treatments, paving the way for future implantable bioelectronic therapeutics. PMID:26601181

  15. Dental implants in patients with bruxing habits.

    PubMed

    Lobbezoo, F; Brouwers, J E I G; Cune, M S; Naeije, M

    2006-02-01

    Bruxism (teeth grinding and clenching) is generally considered a contraindication for dental implants, although the evidence for this is usually based on clinical experience only. So far, studies to the possible cause-and-effect relationship between bruxism and implant failure do not yield consistent and specific outcomes. This is partly because of the large variation in the literature in terms of both the technical aspects and the biological aspects of the study material. Although there is still no proof for the suggestion that bruxism causes an overload of dental implants and of their suprastructures, a careful approach is recommended. There are a few practical guidelines as to minimize the chance of implant failure. Besides the recommendation to reduce or eliminate bruxism itself, these guidelines concern the number and dimensions of the implants, the design of the occlusion and articulation patterns, and the protection of the final result with a hard occlusal stabilization splint (night guard). PMID:16457676

  16. Pelvis MRI scan

    MedlinePlus

    ... The table slides into the middle of the MRI machine. Small devices, called coils, may be placed around ... anxious. Or your provider may suggest an open MRI in which the machine is not as close to the body. Before ...

  17. What Is Chest MRI?

    MedlinePlus

    ... page from the NHLBI on Twitter. What Is Chest MRI? Chest MRI (magnetic resonance imaging) is a safe, noninvasive ... creates detailed pictures of the structures in your chest, such as your chest wall, heart, and blood ...

  18. Arm MRI scan

    MedlinePlus

    ... arm MRI (magnetic resonance imaging) scan uses strong magnets to create pictures of the upper and lower ... in your eyes) Because the MRI contains strong magnets, metal objects are not allowed into the room ...

  19. Breast MRI scan

    MedlinePlus

    ... breast MRI may be done in combination with mammography or ultrasound . It is not a replacement for mammography. ... breast screening with MRI as an adjunct to mammography. CA Cancer J Clin . 2007;57:75-89. ...

  20. Lumbar MRI scan

    MedlinePlus

    ... resonance imaging (MRI) scan uses energy from strong magnets to create pictures of the lower part of ... in your eyes) Because the MRI contains strong magnets, metal objects are not allowed into the room ...

  1. Osteochondritis Dessicans- Primary Fixation using Bioabsorbable Implants

    PubMed Central

    Galagali, Anand; Rao, Muralidhar

    2012-01-01

    Introduction: Osteochondritis dessicans (OCD) is a localized condition where a section of articular cartilage and underlying subchondral bone separate from the joint surface. It is important to diagnose unstable OCD early and fix the fragments primarily as the results of any surgical management at late presentations are guarded. Use of bioabsorbable implants for fixing OCD is recent and we report one such case in grade IV OCD. Case Report: We present a 14 year old girl who came with a history of acute pain, swelling, inability to bear weight on the right knee following a dance practice. MRI showed stage IV osteochondral fragment measuring 20x 8mm lying free. This was primarily fixed with bioabsorbable implants. 10 months follow up showed excellent clinical and functional results. Conclusion: This case highlights the advantages of early primary fixation whenever possible. By far, to our knowledge, this is the first case of successful treatment of stage IV OCD using bioabsorbable implants.

  2. MRI findings in pediatric patients with scurvy.

    PubMed

    Gulko, Edwin; Collins, Lee K; Murphy, Robyn C; Thornhill, Beverly A; Taragin, Benjamin H

    2015-02-01

    In modern times scurvy is a rarely encountered disease caused by ascorbic acid (vitamin C) deficiency. However, sporadic cases of scurvy persist, particularly within the pediatric population. Recent individual case reports highlight an increased incidence of scurvy among patients with autism or developmental delay, with isolated case reports detailing the magnetic resonance imaging (MRI) findings of scurvy in these pediatric populations. We present the MRI findings of scurvy in four patients with autism or developmental delay, and review the literature on MRI findings in pediatric patients with scurvy. Despite its rarity, the radiologist must consider scurvy in a pediatric patient with a restricted diet presenting with arthralgia or myalgia. PMID:25109378

  3. MRI in cranial tuberculosis.

    PubMed

    Just, M; Higer, H P; Betting, O; Bockenheimer, S; Pfannenstiel, P

    1987-11-01

    A case of multiple intracranial tuberculomas is presented. CT and MRI findings are discussed and compared. MRI showed multiple tuberculomas characterised by the same signal intensity as the surrounding brain parenchyma. Differentiation could be achieved only by the perifocal oedema of high signal intensity. Changes of the lesions during chemotherapy were monitored by CT and MRI and the results are presented. PMID:3691545

  4. Background parenchymal enhancement in preoperative breast MRI

    PubMed Central

    Kohara, Satoko; Ishigaki, Satoko; Satake, Hiroko; Kawamura, Akiko; Kawai, Hisashi; Kikumori, Toyone; Naganawa, Shinji

    2015-01-01

    ABSTRACT We aimed to assess the influence of background parenchymal enhancement (BPE) on surgical planning performed using preoperative MRI for breast cancer evaluation. Between January 2009 and December 2010, 91 newly diagnosed breast cancer patients (mean age, 55.5 years; range, 30−88 years) who underwent preoperative bilateral breast MRI followed by planned breast conservation therapy were retrospectively enrolled. MRI was performed to assess the tumor extent in addition to mammography and breast ultrasonography. BPE in the contralateral normal breast MRI at the early dynamic phase was visually classified as follows: minimal (n=49), mild (n=27), moderate (n=7), and marked (n=8). The correlations between the BPE grade and age, menopausal status, index tumor size, changes in surgical management based on MRI results, positive predictive value (PPV) of MRI, and surgical margins were assessed. Patients in the strong BPE groups were significantly younger (p=0.002) and generally premenopausal (p<0.001). Surgical treatment was not changed in 67 cases (73.6%), while extended excision and mastectomy were performed in 12 cases (13.2%), each based on additional lesions on MRI. Six of 79 (7.6%) patients who underwent breast conservation therapy had tumor-positive resection margins. In cases where surgical management was changed, the PPV for MRI-detected foci was high in the minimal (91.7%) and mild groups (66.7%), and 0% in the moderate and marked groups (p=0.002). Strong BPE causes false-positive MRI findings and may lead to overly extensive surgery, whereas MRI may be beneficial in select patients with weak BPE. PMID:26412883

  5. Effects of pore size, implantation time, and nano-surface properties on rat skin ingrowth into percutaneous porous titanium implants.

    PubMed

    Farrell, Brad J; Prilutsky, Boris I; Ritter, Jana M; Kelley, Sean; Popat, Ketul; Pitkin, Mark

    2014-05-01

    The main problem of percutaneous osseointegrated implants is poor skin-implant integration, which may cause infection. This study investigated the effects of pore size (Small, 40-100 μm and Large, 100-160 μm), nanotubular surface treatment (Nano), and duration of implantation (3 and 6 weeks) on skin ingrowth into porous titanium. Each implant type was percutaneously inserted in the back of 35 rats randomly assigned to seven groups. Implant extrusion rate was measured weekly and skin ingrowth into implants was determined histologically after harvesting implants. It was found that all three types of implants demonstrated skin tissue ingrowth of over 30% (at week 3) and 50% (at weeks 4-6) of total implant porous area under the skin; longer implantation resulted in greater skin ingrowth (p < 0.05). Only one case of infection was observed (infection rate 2.9%). Small and Nano groups showed the same implant extrusion rate which was lower than the Large group rate (0.06 ± 0.01 vs. 0.16 ± 0.02 cm/week; p < 0.05). Ingrowth area was comparable in the Small, Large, and Nano implants. However, qualitatively, the Nano implants showed greatest cellular inhabitation within first 3 weeks. We concluded that percutaneous porous titanium implants allow for skin integration with the potential for a safe seal. PMID:23703928

  6. Effects of pore size, implantation time and nano-surface properties on rat skin ingrowth into percutaneous porous titanium implants

    PubMed Central

    Farrell, Brad J.; Prilutsky, Boris I.; Ritter, Jana M.; Kelley, Sean; Popat, Ketul; Pitkin, Mark

    2013-01-01

    The main problem of percutaneous osseointegrated implants is poor skin-implant integration, which may cause infection. This study investigated the effects of pore size (Small, 40–100 microns and Large, 100–160 microns), nanotubular surface treatment (Nano), and duration of implantation (3 and 6 weeks) on skin ingrowth into porous titanium. Each implant type was percutaneously inserted in the back of 35 rats randomly assigned to 7 groups. Implant extrusion rate was measured weekly and skin ingrowth into implants was determined histologically after harvesting implants. It was found that all 3 types of implants demonstrated skin tissue ingrowth of over 30% (at week 3) and 50% (at weeks 4–6) of total implant porous area under the skin; longer implantation resulted in greater skin ingrowth (p<0.05). Only one case of infection was observed (infection rate 2.9%). Small and Nano groups showed the same implant extrusion rate which was lower than the Large group rate (0.06±0.01 vs. 0.16 ± 0.02 cm/week; p<0.05). Ingrowth area was comparable in the Small, Large and Nano implants. However, qualitatively, the Nano implants showed greatest cellular inhabitation within first three weeks. We concluded that percutaneous porous titanium implants allow for skin integration with the potential for a safe seal. PMID:23703928

  7. Live nephron imaging by MRI.

    PubMed

    Qian, Chunqi; Yu, Xin; Pothayee, Nikorn; Dodd, Stephen; Bouraoud, Nadia; Star, Robert; Bennett, Kevin; Koretsky, Alan

    2014-11-15

    The local sensitivity of MRI can be improved with small MR detectors placed close to regions of interest. However, to maintain such sensitivity advantage, local detectors normally need to communicate with the external amplifier through cable connections, which prevent the use of local detectors as implantable devices. Recently, an integrated wireless amplifier was developed that can efficiently amplify and broadcast locally detected signals, so that the local sensitivity was enhanced without the need for cable connections. This integrated detector enabled the live imaging of individual glomeruli using negative contrast introduced by cationized ferritin, and the live imaging of renal tubules using positive contrast introduced by gadopentetate dimeglumine. Here, we utilized the high blood flow to image individual glomeruli as hyperintense regions without any contrast agent. These hyperintense regions were identified for pixels with signal intensities higher than the local average. Addition of Mn(2+) allowed the simultaneous detection of both glomeruli and renal tubules: Mn(2+) was primarily reabsorbed by renal tubules, which would be distinguished from glomeruli due to higher enhancement in T1-weighted MRI. Dynamic studies of Mn(2+) absorption confirmed the differential absorption affinity of glomeruli and renal tubules, potentially enabling the in vivo observation of nephron function. PMID:25186296

  8. Magnetic resonance imaging safety in pacemaker and implantable cardioverter defibrillator patients: how far have we come?

    PubMed

    Nordbeck, Peter; Ertl, Georg; Ritter, Oliver

    2015-06-21

    Magnetic resonance imaging (MRI) has long been regarded a general contraindication in patients with cardiovascular implanted electronic devices such as cardiac pacemakers or cardioverter defibrillators (ICDs) due to the risk of severe complications and even deaths caused by interactions of the magnetic resonance (MR) surrounding and the electric devices. Over the last decade, a better understanding of the underlying mechanisms responsible for such potentially life-threatening complications as well as technical advances have allowed an increasing number of pacemaker and ICD patients to safely undergo MRI. This review lists the key findings from basic research and clinical trials over the last 20 years, and discusses the impact on current day clinical practice. With 'MR-conditional' devices being the new standard of care, MRI in pacemaker and ICD patients has been adopted to clinical routine today. However, specific precautions and specifications of these devices should be carefully followed if possible, to avoid patient risks which might appear with new MR technology and further increasing indications and patient numbers. PMID:25796053

  9. Magnetic resonance imaging safety in pacemaker and implantable cardioverter defibrillator patients: how far have we come?

    PubMed Central

    Nordbeck, Peter; Ertl, Georg; Ritter, Oliver

    2015-01-01

    Magnetic resonance imaging (MRI) has long been regarded a general contraindication in patients with cardiovascular implanted electronic devices such as cardiac pacemakers or cardioverter defibrillators (ICDs) due to the risk of severe complications and even deaths caused by interactions of the magnetic resonance (MR) surrounding and the electric devices. Over the last decade, a better understanding of the underlying mechanisms responsible for such potentially life-threatening complications as well as technical advances have allowed an increasing number of pacemaker and ICD patients to safely undergo MRI. This review lists the key findings from basic research and clinical trials over the last 20 years, and discusses the impact on current day clinical practice. With ‘MR-conditional’ devices being the new standard of care, MRI in pacemaker and ICD patients has been adopted to clinical routine today. However, specific precautions and specifications of these devices should be carefully followed if possible, to avoid patient risks which might appear with new MR technology and further increasing indications and patient numbers. PMID:25796053

  10. In-vitro Assessment of Knee MRI in the Presence of Metal Implants Comparing MAVRIC-SL and Conventional FSE Sequences at 1.5 and 3 Tesla Field Strength

    PubMed Central

    Liebl, Hans; Heilmeier, Ursula; Lee, Sonia; Nardo, Lorenzo; Patsch, Janina; Schuppert, Christopher; Han, Misung; Rondak, Ina-Christine; Banerjee, Suchandrima; Koch, Kevin; Link, Thomas M.; Krug, Roland

    2014-01-01

    PURPOSE To assess lesion detection and artifact size reduction of a MAVRIC-SEMAC hybrid sequence (MAVRIC-SL) compared to standard sequences at 1.5T and 3T in porcine knee specimens with metal hardware. METHODS Artificial cartilage and bone lesions of defined size were created in the proximity of titanium and steel screws with 2.5 mm diameter in 12 porcine knee specimens and were imaged at 1.5T and 3T MRI with MAVRIC-SL PD and STIR, standard FSE T2 PD and STIR and fat-saturated T2 FSE sequences. Three radiologists blinded to the lesion locations assessed lesion detection rates on randomized images for each sequence using ROC. Artifact length and width were measured. RESULTS Metal artifact sizes were largest in the presence of steel screws at 3T (FSE T2 FS: 28.7cm2) and 1.5T (16.03cm2). MAVRIC-SL PD and STIR reduced artifact sizes at both 3T (1.43cm2; 2.46cm2) and 1.5T (1.16cm2; 1.59cm2) compared to FS T2 FSE sequences (27.57cm2; 13.20cm2). At 3T, ROC derived AUC values using MAVRIC-SL sequences were significantly higher compared to standard sequences (MAVRIC-PD: 0.87, versus FSE-T2-FS: 0.73 (p=0.025); MAVRIC- STIR: 0.9 versus T2-STIR: 0.78 (p=0.001) and versus FSE-T2-FS: 0.73 (p=0.026)). Similar values were observed at 1.5T. Comparison of 3T and 1.5T showed no significant differences (MAVRIC-SL PD: p=0.382; MAVRIC-SL STIR: p=0.071. CONCLUSION MAVRIC-SL sequences provided superior lesion detection and reduced metal artifact size at both 1.5T and 3T compared to conventionally used FSE sequences. No significant disadvantage was found comparing MAVRIC-SL at 3T and 1.5T, though metal artifacts at 3T were larger. PMID:24912802

  11. Treatment of Infected Facial Implants.

    PubMed

    Mohan, Kriti; Cox, Joshua A; Dickey, Ryan M; Gravina, Paula; Echo, Anthony; Izaddoost, Shayan A; Nguyen, Anh H

    2016-05-01

    Alloplastic facial implants have a wide range of uses to achieve the appropriate facial contour. A variety of materials such as metals, polymers, ceramics and synthetic injectable fillers are available to the reconstructive and aesthetic surgeon. Besides choosing the right surgical technique and the adequate material, the surgeon must be prepared to treat complications. Infection is an uncommon but serious complication that can cause displeasing consequences for the patient. There are few references in literature regarding treatment and management of facial implant-related infections. This study aims to discuss the role of biofilm in predisposing alloplastic materials to infection, to provide a review of literature, to describe our own institutional experience, and to define a patient care pathway for facial implant-associated infection. PMID:27152100

  12. Ex-PRESS glaucoma filter: an MRI compatible metallic orbital foreign body imaged at 1.5 and 3 T

    PubMed Central

    Mabray, M.C.; Uzelac, A.; Talbott, J.F.; Lin, S.C.; Gean, A.D.

    2015-01-01

    AIM To report on the MRI compatibility of the Ex-PRESS glaucoma filtration device, a tiny metallic implant placed into the anterior chamber of the eye that is much smaller than traditional glaucoma shunts, and to educate the radiology community regarding its appearance. MATERIALS AND METHODS Seven patients with Ex-PRESS glaucoma filtration devices were identified that had undergone MRI at San Francisco General Hospital/University of California San Francisco Medical Center by searching and cross-referencing the radiology reporting system and the electronic medical record. MRI images were reviewed for artefact interfering with interpretation. Ophthalmology examinations were reviewed for evidence of complications. RESULTS Eighteen individual MRI examinations were performed during 12 unique MRI events on these 7 patients. 13/18 individual MRI examinations and 7/12 MRI events were performed at 3 T with the others performed at 1.5 T. Mean time from Ex-PRESS implantation to MRI was 17.5 months. Mean time from MRI to first ophthalmology examination was 1.1 months and from MRI to latest ophthalmology examination was 6.6 months. Susceptibility artefact did not interfere with image interpretation and no complications related to MRI were encountered. CONCLUSION The Ex-PRESS glaucoma filtration device appears to be safe for MRI at 1.5 and 3 T and does not produce significant susceptibility artefact to affect diagnostic interpretation adversely. PMID:25735675

  13. Magnetic resonance imaging, pacemakers and implantable cardioverter-defibrillators: current situation and clinical perspective

    PubMed Central

    Götte, M.J.W.; Rüssel, I.K.; de Roest, G.J.; Germans, T.; Veldkamp, R.F.; Knaapen, P.; Allaart, C.P.; van Rossum, A.C.

    2010-01-01

    New developments and expanding indications have resulted in a significant increase in the number of patients with pacemakers and internal cardioverterdefibrillators (ICDs). Because of its unique capabilities, magnetic resonance imaging (MRI) has become one of the most important imaging modalities for evaluation of the central nervous system, tumours, musculoskeletal disorders and some cardiovascular diseases. As a consequence of these developments, an increasing number of patients with implanted devices meet the standard indications for MRI examination. Due to the presence of potential life-threatening risks and interactions, however, pacemakers and ICDs are currently not approved by the Food and Drug Administration (FDA) for use in an MRI scanner. Despite these limitations and restrictions, a limited but still growing number of studies reporting on the effects and safety issues of MRI and implanted devices have been published. Because physicians will be increasingly confronted with the issue of MRI in patients with implanted devices, this overview is given. The effects of MRI on an implanted pacemaker and/or ICDs and vice versa are described and, based on the current literature, a strategy for safe performance of MRI in these patients is proposed. (Neth Heart J 2010;18:31-7.) PMID:20111641

  14. Multisite Infection with Mycobacterium abscessus after Replacement of Breast Implants and Gluteal Lipofilling

    PubMed Central

    Rüegg, Eva; Cheretakis, Alexandre; Modarressi, Ali; Harbarth, Stephan; Pittet-Cuénod, Brigitte

    2015-01-01

    Introduction. Medical tourism for aesthetic surgery is popular. Nontuberculous mycobacteria (NTM) occasionally cause surgical-site infections. As NTM grow in biofilms, implantations of foreign bodies are at risk. Due to late manifestation, infections occur when patients are back home, where they must be managed properly. Case Report. A 39-year-old healthy female was referred for acute infection of the right gluteal area. Five months before, she had breast implants replacement, abdominal liposuction, and gluteal lipofilling in Mexico. Three months postoperatively, implants were removed for NTM-infection in Switzerland. Adequate antibiotic treatment was stopped after seven days for drug-related hepatitis. At entrance, gluteal puncture for bacterial analysis was performed. MRI showed large subcutaneous collection. Debridement under general anaesthesia was followed by open wound management. Total antibiotic treatment was 20 weeks. Methods. Bacterial analysis of periprosthetic and gluteal liquids included Gram-stain plus acid-fast stain, and aerobic, anaerobic and mycobacterial cultures.  Results. In periprosthetic fluid, Mycobacterium abscessus, Propionibacterium, and Staphylococcus epidermidis were identified. The same M. abscessus strain was found gluteally. The gluteal wound healed within six weeks. At ten months' follow-up, gluteal asymmetry persists for deep scarring. Conclusion. This case presents major complications of multisite aesthetic surgery. Surgical-site infections in context of medical tourism need appropriate bacteriological investigations, considering potential NTM-infections. PMID:25893122

  15. Rat model of cholelithiasis with human gallstones implanted in cholestasis-induced virtual gallbladder

    PubMed Central

    Cona, Marlein Miranda; Liu, Yewei; Yin, Ting; Feng, Yuanbo; Chen, Feng; Mulier, Stefaan; Li, Yue; Zhang, Jian; Oyen, Raymond; Ni, Yicheng

    2016-01-01

    AIM: To facilitate translational research on cholelithiasis, we have developed a rat model of human gallstones by exploiting the unique biliopancreatic features of this species. METHODS: Under anesthesia, 16 adult rats of equal genders underwent two times of abdominal surgery. First, their common bile duct (CBD) was ligated to cause cholestasis by total biliary obstruction (TBO). On day 0, 1, 3, 7, 14, 21 and 28 after TBO, magnetic resonance imaging (MRI) was conducted to monitor the dilatation of the CBD, and blood was sampled to analyze total serum bilirubin (TSB). Secondly, on day 30, the abdomen was re-opened and gallstone(s) collected from human patients were implanted in the dilated CBD as a virtual gallbladder (VGB), which was closed by suture ligation. This rat cholelithiasis model was examined by MRI, clinical observation, microcholangiography and histology. RESULTS: All rats survived two laparotomies. After ligation, the CBD was dilated to a stable size of 4 to 30 mm in diameter on day 21-28, which became a VGB. The rats initially showed signs of jaundice that diminished over time, which paralleled with the evolving TSB levels from 0.6 ± 0.3 mg/dL before ligation, through a peak of 10.9 ± 1.9 mg/dL on day 14, until a nearly normalized value after day 28. The dilated CBD with thickened wall allowed an incision for implantation of human gallstones of 1-10 mm in diameter. The rat cholelithiasis was proven by in vivo MRI and postmortem microcholangiography and histomorphology. CONCLUSION: A rat model cholelithiasis with human gallstones has been established, which proves feasible, safe, reliable, nontoxic and cost-effective. Given the gallstones of human origin, applications of this model may be of help in translational research such as optical detection and lysis of gallstones by systemic drug administration. PMID:27376020

  16. Implant failure associated with actinomycosis in a medically compromised patient.

    PubMed

    Sun, Chun-Xiao; Henkin, Jeffrey M; Ririe, Craig; Javadi, Elham

    2013-04-01

    Oral actinomycosis is not a common disease, but it can cause massive destruction. This article reports a case of implant failure associated with actinomycosis. A 55-year-old Caucasian male patient had tooth #20 extracted years ago and an implant placed 3 years ago. The #20 implant area developed an abscess about 1½ years after implant placement. Radiographic findings revealed a large radiolucency on the mesial aspect of the #20 implant. The implant was surgically removed and the lesion thoroughly debrided. The patient experienced severe pain when the apical soft tissue was curreted following implant removal. A periapical radiograph revealed that the lesion approached the mental foramen. A short course of antibiotics was prescribed. Histological observation found sulfur granules, which were found to be actinomycotic colonies. Peri-implant actinomycosis was diagnosed. No recurrence had occurred at the 1-year follow-up. PMID:21767210

  17. The effect of co-implantation on the electrical activity of implanted carbon in GaAs

    SciTech Connect

    Moll, A.J.; Walukiewicz, W.; Yu, K.M.; Hansen, W.L.; Haller, E.E.

    1991-11-01

    We have undertaken a systematic study of the effect of co- implantation on the electrical properties of C implanted in GaAs. Two effects have been studied, the additional damage caused by co- implantation and the stoichiometry in the implanted layer. A series of co-implant ions were used: group III (B, Al, Ga), group V (N, P, As) and noble gases (Ar, Kr). Co-implantation of ions which create an amorphous layer was found to increase the electrical activity of C. Once damage was created, maintaining stoichiometric balance by co-implantation of a group III further increased the fraction of electrically active carbon impurities. Co-implantation of Ga and rapid thermal annealing at 950{degree}C for 10s resulted in carbon activation as high as 68%, the highest value ever reported.

  18. Structural brain MRI studies in eye diseases: are they clinically relevant? A review of current findings.

    PubMed

    Prins, Doety; Hanekamp, Sandra; Cornelissen, Frans W

    2016-03-01

    Many eye diseases reduce visual acuity or are associated with visual field defects. Because of the well-defined retinotopic organization of the connections of the visual pathways, this may affect specific parts of the visual pathways and cortex, as a result of either deprivation or transsynaptic degeneration. For this reason, over the past several years, numerous structural magnetic resonance imaging (MRI) studies have examined the association of eye diseases with pathway and brain changes. Here, we review structural MRI studies performed in human patients with the eye diseases albinism, amblyopia, hereditary retinal dystrophies, age-related macular degeneration (AMD) and glaucoma. We focus on two main questions. First, what have these studies revealed? Second, what is the potential clinical relevance of their findings? We find that all the aforementioned eye diseases are indeed associated with structural changes in the visual pathways and brain. As such changes have been described in very different eye diseases, in our view the most parsimonious explanation is that these are caused by the loss of visual input and the subsequent deprivation of the visual pathways and brain regions, rather than by transsynaptic degeneration. Moreover, and of clinical relevance, for some of the diseases - in particular glaucoma and AMD - present results are compatible with the view that the eye disease is part of a more general neurological or neurodegenerative disorder that also affects the brain. Finally, establishing structural changes of the visual pathways has been relevant in the context of new therapeutic strategies to restore retinal function: it implies that restoring retinal function may not suffice to also effectively restore vision. Future structural MRI studies can contribute to (i) further establish relationships between ocular and neurological neurodegenerative disorders, (ii) investigate whether brain degeneration in eye diseases is reversible, (iii) evaluate the use

  19. Radiation induced currents in MRI RF coils: application to linac/MRI integration

    PubMed Central

    Burke, B; Fallone, B G; Rathee, S

    2010-01-01

    The integration of medical linear accelerators (linac) with magnetic resonance imaging (MRI) systems is advancing the current state of image-guided radiotherapy. The MRI in these integrated units will provide real-time, accurate tumor locations for radiotherapy treatment, thus decreasing geometric margins around tumors and reducing normal tissue damage. In the real-time operation of these integrated systems, the radiofrequency (RF) coils of MRI will be irradiated with radiation pulses from the linac. The effect of pulsed radiation on MRI radio frequency (RF) coils is not known and must be studied. The instantaneous radiation induced current (RIC) in two different MRI RF coils were measured and presented. The frequency spectra of the induced currents were calculated. Some basic characterization of the RIC was also done: isolation of the RF coil component responsible for RIC, dependence of RIC on dose rate, and effect of wax buildup placed on coil on RIC. Both the time and frequency characteristics of the RIC were seen to vary with the MRI RF coil used. The copper windings of the RF coils were isolated as the main source of RIC. A linear dependence on dose rate was seen. The RIC was decreased with wax buildup, suggesting an electronic disequilibrium as the cause of RIC. This study shows a measurable RIC present in MRI RF coils. This unwanted current could be possibly detrimental to the signal to noise ratio in MRI and produce image artifacts. PMID:20071754

  20. Influence of dental materials on dental MRI

    PubMed Central

    Tymofiyeva, O; Vaegler, S; Rottner, K; Boldt, J; Hopfgartner, AJ; Proff, PC; Richter, E-J; Jakob, PM

    2013-01-01

    Objectives: To investigate the potential influence of standard dental materials on dental MRI (dMRI) by estimating the magnetic susceptibility with the help of the MRI-based geometric distortion method and to classify the materials from the standpoint of dMRI. Methods: A series of standard dental materials was studied on a 1.5 T MRI system using spin echo and gradient echo pulse sequences and their magnetic susceptibility was estimated using the geometric method. Measurements on samples of dental materials were supported by in vivo examples obtained in dedicated dMRI procedures. Results: The tested materials showed a range of distortion degrees. The following materials were classified as fully compatible materials that can be present even in the tooth of interest: the resin-based sealer AH Plus® (Dentsply, Maillefer, Germany), glass ionomer cement, gutta-percha, zirconium dioxide and composites from one of the tested manufacturers. Interestingly, composites provided by the other manufacturer caused relatively strong distortions and were therefore classified as compatible I, along with amalgam, gold alloy, gold–ceramic crowns, titanium alloy and NiTi orthodontic wires. Materials, the magnetic susceptibility of which differed from that of water by more than 200 ppm, were classified as non-compatible materials that should not be present in the patient’s mouth for any dMRI applications. They included stainless steel orthodontic appliances and CoCr. Conclusions: A classification of the materials that complies with the standard grouping of materials according to their magnetic susceptibility was proposed and adopted for the purposes of dMRI. The proposed classification can serve as a guideline in future dMRI research. PMID:23610088

  1. Immediate bleeding complications in dental implants: A systematic review

    PubMed Central

    Balaguer-Martí, José-Carlos; Peñarrocha-Oltra, David; Balaguer-Martínez, José

    2015-01-01

    Objective: A review is made of the immediate or immediate postoperative bleeding complications in dental implants, with a view to identifying the areas of greatest bleeding risk, the causes of bleeding, the length of the implants associated with bleeding, the most frequently implicated blood vessels, and the treatments used to resolve these complications. Material and Methods: A Medline (PubMed) and Embase search was made of articles on immediate bleeding complications in dental implants published in English up until May 2014. Inclusion criteria: studies in humans subjects with severe bleeding immediately secondary to implant placement, which reported the time until the hemorrhage, the implant lenght, the possible cause of bleeding and the treatment. Exclusion criteria: patients receiving anticoagulation treatment. Results: Fifteen articles met the inclusion criteria. The area with the largest number of bleeding complications corresponded to the mandibular canine. The cause of bleeding was lingual cortical bone perforation during implant placement, with damage to the sublingual artery. The implants associated with bleeding were those measuring 15 mm in length or more. Management focused on securing the airway (with intubation or tracheostomy if necessary), with bleeding control. Conclusions: It’s important to pay special attention when the implants are placed in the mandibular anterior zone, especially if long implants are used. The most frequently cause of bleeding was the perforation of the lingual plate. Treatment involves securing the airway, with bleeding control. Key words:Hemorrhage, complications, immediate, bleeding, dental implants. PMID:25475779

  2. A technique for removal of a fractured implant abutment screw.

    PubMed

    Kurt, Murat; Güler, Ahmet Umut; Duran, İbrahim

    2013-12-01

    The aim of this technique report was to present a procedure for removal of a fractured implant abutment screw. Whatever the cause, when an abutment fracture has occurred, the fractured screw segment inside the implant must be removed. The methods used by the clinicians may include the use of an endo-explorer self-made screwdriver and the use of implant repair kit available for some implant systems. The advantage of the presented method is that it may be extended to other implant systems that do not have a special repair kit and also that the technique is simple and does not require special equipment. PMID:21905898

  3. Learning distance function for regression-based 4D pulmonary trunk model reconstruction estimated from sparse MRI data

    NASA Astrophysics Data System (ADS)

    Vitanovski, Dime; Tsymbal, Alexey; Ionasec, Razvan; Georgescu, Bogdan; Zhou, Shaohua K.; Hornegger, Joachim; Comaniciu, Dorin

    2011-03-01

    Congenital heart defect (CHD) is the most common birth defect and a frequent cause of death for children. Tetralogy of Fallot (ToF) is the most often occurring CHD which affects in particular the pulmonary valve and trunk. Emerging interventional methods enable percutaneous pulmonary valve implantation, which constitute an alternative to open heart surgery. While minimal invasive methods become common practice, imaging and non-invasive assessment tools become crucial components in the clinical setting. Cardiac computed tomography (CT) and cardiac magnetic resonance imaging (cMRI) are techniques with complementary properties and ability to acquire multiple non-invasive and accurate scans required for advance evaluation and therapy planning. In contrary to CT which covers the full 4D information over the cardiac cycle, cMRI often acquires partial information, for example only one 3D scan of the whole heart in the end-diastolic phase and two 2D planes (long and short axes) over the whole cardiac cycle. The data acquired in this way is called sparse cMRI. In this paper, we propose a regression-based approach for the reconstruction of the full 4D pulmonary trunk model from sparse MRI. The reconstruction approach is based on learning a distance function between the sparse MRI which needs to be completed and the 4D CT data with the full information used as the training set. The distance is based on the intrinsic Random Forest similarity which is learnt for the corresponding regression problem of predicting coordinates of unseen mesh points. Extensive experiments performed on 80 cardiac CT and MR sequences demonstrated the average speed of 10 seconds and accuracy of 0.1053mm mean absolute error for the proposed approach. Using the case retrieval workflow and local nearest neighbour regression with the learnt distance function appears to be competitive with respect to "black box" regression with immediate prediction of coordinates, while providing transparency to the

  4. The effect of implant angulation and splinting on stress distribution in implant body and supporting bone: A finite element analysis

    PubMed Central

    Behnaz, Ebadian; Ramin, Mosharraf; Abbasi, Samaneh; Pouya, Memar Ardestani; Mahmood, Farzin

    2015-01-01

    Objective: The aim of this study was to investigate the influence of implant crown splinting and the use of angulated abutment on stress distribution in implant body and surrounding bone by three-dimensional finite element analysis. Materials and Methods: For this study, three models with two implants at the site of mandibular right second premolar and first molar were designed (1): Both implants, parallel to adjacent teeth, with straight abutments (2): Anterior implant with 15 mesial angulations and posterior implant were placed parallel to adjacent tooth, (3): Both implants with 15 mesial angulations and parallel to each other with 15° angulated abutments. Restorations were modeled in two shapes (splinted and nonsplinted). Loading in tripod manner as each point 50 N and totally 300 N was applied. Stress distribution in relation to splinting or nonsplinting restorations and angulations was done with ABAQUS6.13. Results: Splinting the restorations in all situations, led to lower stresses in all implant bodies, cortical bone and spongy bone except for the spongy bone around angulated first molar. Angulated implant in nonsplinted restoration cause lower stresses in implant body and bone but in splinted models more stresses were seen in implant body in comparison with straight abutment (model 2). Stresses in nonsplinted and splinted restorations in cortical bone of angulated molar region were more than what was observed in straight molar implant (model 3). Conclusion: Implant restorations splinting lead to a better distribution of stresses in implant bodies and bone in comparison with nonsplinted restorations, especially when the load is applied off center to implant body. Angulations of implant can reduce stresses when the application of the load is in the same direction as the implant angulation. PMID:26430356

  5. MRI of the shoulder

    SciTech Connect

    Zlatkin, M.B.; Iannotti, J.P.; Schnall, M.D.

    1991-01-01

    This book reports on the use of magnetic resonance imaging (MRI) in evaluating shoulder disorders. The book gives detailed information on MRI techniques and shoulder anatomy, describes and illustrates MRI findings for a wide range of shoulder disorders, and explains how abnormalities seen on MIR images relate to pathophysiology and clinical signs. Special attention is given to imaging of rotator cuff disease and shoulder instability conditions for which MRI is the imaging procedure of choice. Complementing the text are 365 high-quality scans depicting normal shoulder anatomy and showing the wide variety of pathologic findings encountered in practice.

  6. Implant Site Development for Enhancing Esthetics of Soft and Hard Tissue and Simplification of Implant Surgery Using a Forced Eruption.

    PubMed

    Joo, Ji-Young; Son, Sieun; Lee, Ju-Youn

    2016-01-01

    The keys to successful esthetic implant therapy in the anterior region are natural-looking implant restorations and an adequate alveolar ridge volume. Destruction of periodontal tissue resulting from periodontal and/or endodontic inflammation causes esthetic problems. Forced eruption is a valuable adjunct to augmenting the soft and hard tissue where the alveolar ridge is insufficient for esthetics. In this article, forced eruption was adopted for implant site development prior to implant placement and the periodontal tissue was augmented vertically using this technique. This technique simplified the surgical implant procedure without a need for advanced augmentation. PMID:27333017

  7. Atraumatic extraction, implant placement and immediate provisionalization.

    PubMed

    Tavarez, Rudys Rodolfo de Jesus; Calixto, Amanda Martins; Maia Filho, Etevaldo Matos; Bandeca, Matheus Coelho; Firoozmand, Leily Macedo; Gomes, Mario Gilson Nina; Malheiros, Adriana Santos

    2014-01-01

    Front tooth extraction typically results in significant loss of hard and soft tissue volume, both in the vestibular-lingual and mesiodistal directions. As these changes can compromise the esthetic results of prosthetic rehabilitation, extraction techniques that cause minimal trauma to the remnant tissues are applied in combination with immediate implant placement to minimize such alterations. The case reported in the present article illustrates a therapeutic plan consisting of atraumatic extraction followed by immediate implant placement and provisionalization. When carefully indicated and planned, our results indicate that this technique may provide promising immediate results relative to the maintenance and stability of the peri-implanted tissues. PMID:25576122

  8. Photodynamic therapy in peri-implantitis

    NASA Astrophysics Data System (ADS)

    Leretter, Marius; Cândea, Adrian; Topala, Florin

    2014-01-01

    Peri-implantitis is like Damocles sword, threatening over our final results as is the most common cause of implant failure. It is, was and will be one of the most challenging tasks for the practitioner to deal with. The rough implant surface offers the ideal conditions for the pathogenic bacteria to stick and multiply. Even more, the growing mature biofilm is harder to eliminate. Mechanical cleaning and rinsing is not capable to destroy it entirely. Most treatment protocols include strong antibiotics, disregarding their side effects and interactions with other medications.

  9. Hair implant complications.

    PubMed

    Hanke, C W; Norins, A L; Pantzer, J G; Bennett, J E

    1981-04-01

    Four men who underwent hair implantation for pattern baldness were treated for complications such as infection, foreign-body reaction, pruritus, and scarring. The complications were similar to those reported with synthetic modacrylic fiber implants that have been used for the same purpose. Although we believe this is the first article to report complications from hair implants, the illogical basis of the procedure suggests that complications will occur in many unsuspecting patients who undergo hair implantation. PMID:7009899

  10. Percutaneous Pulmonary Valve Implantation

    PubMed Central

    Lee, Hyoung-Doo

    2012-01-01

    Pulmonary regurgitation (PR) is a frequent sequelae after repair of tetralogy of Fallot, pulmonary atresia, truncus arteriosus, Rastelli and Ross operation. Due to patient growth and conduit degeneration, these conduits have to be changed frequently due to regurgitation or stenosis. However, morbidity is significant in these repeated operations. To prolong conduit longevity, bare-metal stenting in the right ventricular outflow tract (RVOT) obstruction has been performed. Stenting the RVOT can reduce the right ventricular pressure and symptomatic improvement, but it causes PR with detrimental effects on the right ventricle function and risks of arrhythmia. Percutaneous pulmonary valve implantation has been shown to be a safe and effective treatment for patients with pulmonary valve insufficiency, or stenotic RVOTs. PMID:23170091

  11. Implantable Heart Aid

    NASA Technical Reports Server (NTRS)

    1984-01-01

    CPI's human-implantable automatic implantable defibrillator (AID) is a heart assist system, derived from NASA's space circuitry technology, that can prevent erratic heart action known as arrhythmias. Implanted AID, consisting of microcomputer power source and two electrodes for sensing heart activity, recognizes onset of ventricular fibrillation (VF) and delivers corrective electrical countershock to restore rhythmic heartbeat.

  12. Extraocular Surgical Approach for Placement of Subretinal Implants in Blind Patients: Lessons from Cochlear-Implants.

    PubMed

    Koitschev, Assen; Stingl, Katarina; Bartz-Schmidt, Karl Ulrich; Braun, Angelika; Gekeler, Florian; Greppmaier, Udo; Sachs, Helmut; Peters, Tobias; Wilhelm, Barbara; Zrenner, Eberhart; Besch, Dorothea

    2015-01-01

    In hereditary retinal diseases photoreceptors progressively degenerate, often causing blindness without therapy being available. Newly developed subretinal implants can substitute functions of photoreceptors. Retina implant extraocular surgical technique relies strongly on cochlear-implant know-how. However, a completely new surgical approach providing safe handling of the photosensor array had to be developed. The Retina Implant Alpha IMS consisting of a subretinal microphotodiode array and cable linked to a cochlear-implant-like ceramic housing was introduced via a retroauricular incision through a subperiosteal tunnel above the zygoma into the orbit using a specially designed trocar. Implant housing was fixed in a bony bed within a tight subperiosteal pocket in all patients. Primary outcomes were patient short term safety as well as effectiveness. Nine patients participated in the first part of the multicenter trial and received the subretinal visual implant in one eye. In all cases microphotodiode array pull-through procedure and stable positioning were possible without affecting the device function. No intraoperative complications were encountered. The minimally invasive suprazygomatic tunneling technique for the sensor unit as well as a subperiosteal pocket fixation of the implant housing provides a safe extraocular implantation approach of a subretinal device with a transcutaneous extracorporeal power supply. PMID:26783453

  13. Extraocular Surgical Approach for Placement of Subretinal Implants in Blind Patients: Lessons from Cochlear-Implants

    PubMed Central

    Koitschev, Assen; Stingl, Katarina; Bartz-Schmidt, Karl Ulrich; Braun, Angelika; Gekeler, Florian; Greppmaier, Udo; Sachs, Helmut; Peters, Tobias; Wilhelm, Barbara; Zrenner, Eberhart; Besch, Dorothea

    2015-01-01

    In hereditary retinal diseases photoreceptors progressively degenerate, often causing blindness without therapy being available. Newly developed subretinal implants can substitute functions of photoreceptors. Retina implant extraocular surgical technique relies strongly on cochlear-implant know-how. However, a completely new surgical approach providing safe handling of the photosensor array had to be developed. The Retina Implant Alpha IMS consisting of a subretinal microphotodiode array and cable linked to a cochlear-implant-like ceramic housing was introduced via a retroauricular incision through a subperiosteal tunnel above the zygoma into the orbit using a specially designed trocar. Implant housing was fixed in a bony bed within a tight subperiosteal pocket in all patients. Primary outcomes were patient short term safety as well as effectiveness. Nine patients participated in the first part of the multicenter trial and received the subretinal visual implant in one eye. In all cases microphotodiode array pull-through procedure and stable positioning were possible without affecting the device function. No intraoperative complications were encountered. The minimally invasive suprazygomatic tunneling technique for the sensor unit as well as a subperiosteal pocket fixation of the implant housing provides a safe extraocular implantation approach of a subretinal device with a transcutaneous extracorporeal power supply. PMID:26783453

  14. Chimeric peptides as implant functionalization agents for titanium alloy implants with antimicrobial properties

    PubMed Central

    Yucesoy, Deniz T.; Hnilova, Marketa; Boone, Kyle; Arnold, Paul M.; Snead, Malcolm L.

    2015-01-01

    Implant-associated infections can have severe effects on the longevity of implant devices and they also represent a major cause of implant failures. Treating these infections associated with implants by antibiotics is not always an effective strategy due to poor penetration rates of antibiotics into biofilms. Additionally, emerging antibiotic resistance poses serious concerns. There is an urge to develop effective antibacterial surfaces that prevent bacterial adhesion and proliferation. A novel class of bacterial therapeutic agents, known as antimicrobial peptides (AMP’s), are receiving increasing attention as an unconventional option to treat septic infection, partly due to their capacity to stimulate innate immune responses and for the difficulty of microorganisms to develop resistance towards them. While host- and bacterial- cells compete in determining the ultimate fate of the implant, functionalization of implant surfaces with antimicrobial peptides can shift the balance and prevent implant infections. In the present study, we developed a novel chimeric peptide to functionalize the implant material surface. The chimeric peptide simultaneously presents two functionalities, with one domain binding to a titanium alloy implant surface through a titanium-binding domain while the other domain displays an antimicrobial property. This approach gains strength through control over the bio-material interfaces, a property built upon molecular recognition and self-assembly through a titanium alloy binding domain in the chimeric peptide. The efficiency of chimeric peptide both in-solution and absorbed onto titanium alloy surface was evaluated in vitro against three common human host infectious bacteria, S. mutans, S. epidermidis, and E. coli. In biological interactions such as occurs on implants, it is the surface and the interface that dictate the ultimate outcome. Controlling the implant surface by creating an interface composed chimeric peptides may therefore open up

  15. Chimeric Peptides as Implant Functionalization Agents for Titanium Alloy Implants with Antimicrobial Properties

    NASA Astrophysics Data System (ADS)

    Yucesoy, Deniz T.; Hnilova, Marketa; Boone, Kyle; Arnold, Paul M.; Snead, Malcolm L.; Tamerler, Candan

    2015-04-01

    Implant-associated infections can have severe effects on the longevity of implant devices and they also represent a major cause of implant failures. Treating these infections associated with implants by antibiotics is not always an effective strategy due to poor penetration rates of antibiotics into biofilms. Additionally, emerging antibiotic resistance poses serious concerns. There is an urge to develop effective antibacterial surfaces that prevent bacterial adhesion and proliferation. A novel class of bacterial therapeutic agents, known as antimicrobial peptides (AMPs), are receiving increasing attention as an unconventional option to treat septic infection, partly due to their capacity to stimulate innate immune responses and for the difficulty of microorganisms to develop resistance towards them. While host and bacterial cells compete in determining the ultimate fate of the implant, functionalization of implant surfaces with AMPs can shift the balance and prevent implant infections. In the present study, we developed a novel chimeric peptide to functionalize the implant material surface. The chimeric peptide simultaneously presents two functionalities, with one domain binding to a titanium alloy implant surface through a titanium-binding domain while the other domain displays an antimicrobial property. This approach gains strength through control over the bio-material interfaces, a property built upon molecular recognition and self-assembly through a titanium alloy binding domain in the chimeric peptide. The efficiency of chimeric peptide both in-solution and absorbed onto titanium alloy surface was evaluated in vitro against three common human host infectious bacteria, Streptococcus mutans, Staphylococcus epidermidis, and Escherichia coli. In biological interactions such as occur on implants, it is the surface and the interface that dictate the ultimate outcome. Controlling the implant surface by creating an interface composed chimeric peptides may therefore

  16. MRI-Safe Robot for Endorectal Prostate Biopsy.

    PubMed

    Stoianovici, Dan; Kim, Chunwoo; Srimathveeravalli, Govindarajan; Sebrecht, Peter; Petrisor, Doru; Coleman, Jonathan; Solomon, Stephen B; Hricak, Hedvig

    2013-09-16

    This paper reports the development of an MRI-Safe robot for direct (interventional) MRI-guided endorectal prostate biopsy. The robot is constructed of nonmagnetic and electrically nonconductive materials, and is electricity free, using pneumatic actuation and optical sensors. Targeting biopsy lesions of MRI abnormality presents substantial clinical potential for the management of prostate cancer. The paper describes MRI-Safe requirements, presents the kinematic architecture, design and construction of the robot, and a comprehensive set of preclinical tests for MRI compatibility and needle targeting accuracy. The robot has a compact and simple 3 degree-of-freedom (DoF) structure, two for orienting a needle-guide and one to preset the depth of needle insertion. The actual insertion is performed manually through the guide and up to the preset depth. To reduce the complexity and size of the robot next to the patient, the depth setting DoF is remote. Experimental results show that the robot is safe to use in any MRI environment (MRI-Safe). Comprehensive MRI tests show that the presence and motion of the robot in the MRI scanner cause virtually no image deterioration or signal to noise ratio (SNR) change. Robot's accuracy in bench test, CT-guided in-vitro, MRI-guided in-vitro and animal tests are 0.37mm, 1.10mm, 2.09mm, and 2.58mm respectively. These values are acceptable for clinical use. PMID:25378897

  17. MRI-Safe Robot for Endorectal Prostate Biopsy

    PubMed Central

    Stoianovici, Dan; Kim, Chunwoo; Srimathveeravalli, Govindarajan; Sebrecht, Peter; Petrisor, Doru; Coleman, Jonathan; Solomon, Stephen B.; Hricak, Hedvig

    2014-01-01

    This paper reports the development of an MRI-Safe robot for direct (interventional) MRI-guided endorectal prostate biopsy. The robot is constructed of nonmagnetic and electrically nonconductive materials, and is electricity free, using pneumatic actuation and optical sensors. Targeting biopsy lesions of MRI abnormality presents substantial clinical potential for the management of prostate cancer. The paper describes MRI-Safe requirements, presents the kinematic architecture, design and construction of the robot, and a comprehensive set of preclinical tests for MRI compatibility and needle targeting accuracy. The robot has a compact and simple 3 degree-of-freedom (DoF) structure, two for orienting a needle-guide and one to preset the depth of needle insertion. The actual insertion is performed manually through the guide and up to the preset depth. To reduce the complexity and size of the robot next to the patient, the depth setting DoF is remote. Experimental results show that the robot is safe to use in any MRI environment (MRI-Safe). Comprehensive MRI tests show that the presence and motion of the robot in the MRI scanner cause virtually no image deterioration or signal to noise ratio (SNR) change. Robot’s accuracy in bench test, CT-guided in-vitro, MRI-guided in-vitro and animal tests are 0.37mm, 1.10mm, 2.09mm, and 2.58mm respectively. These values are acceptable for clinical use. PMID:25378897

  18. Effect of Healing Time on Bone-Implant Contact of Orthodontic Micro-Implants: A Histologic Study

    PubMed Central

    Ramazanzadeh, Barat Ali; Fatemi, Kazem; Dehghani, Mahboobe; Mohtasham, Nooshin; Jahanbin, Arezoo; Sadeghian, Hamed

    2014-01-01

    Objectives. This study aimed to evaluate the effect of immediate and delayed loading of orthodontic micro-implants on bone-implant contact. Materials and Methods. Sixty four micro-implants were implanted in dog's jaw bone. The micro-implants were divided into loaded and unloaded (control) groups. The control group had two subgroups: four and eight weeks being implanted. The loaded group had two subgroups of immediate loading and delayed (after four weeks healing) loading. Loaded samples were subjected to 200g load for four weeks. After sacrificing the animals micro-implants and surrounding tissues were observed histologically. Bone-implant contact ratios (BIC) were calculated and different groups' results were compared by three-way ANOVA. Results. Mean survival rate was 96.7% in general. Survival rates were 96.7%, 94.4% and 100% for control, immediate and delayed loaded groups, respectively. BIC values were not significantly different in loaded and control groups, immediate and delayed loading groups, and pressure and tension sides. Mandibular micro-implants had significantly higher BIC than maxillary ones in immediate loading, 4-weeks control, and 8-weeks control groups (P = 0.021, P = 0.009, P = 0.003, resp.). Conclusion Immediate or delayed loading of micro-implants in dog did not cause significant difference in Bone-implant contact which could be concluded that healing time had not significant effect on micro-implant stability. PMID:25006463

  19. Sea urchin puncture resulting in PIP joint synovial arthritis: case report and MRI study.

    PubMed

    Liram, N; Gomori, M; Perouansky, M

    2000-01-01

    Of the 600 species of sea urchins, approximately 80 may be venomous to humans. The long spined or black sea urchin, Diadema setosum may cause damage by the breaking off of its brittle spines after they penetrate the skin. Synovitis followed by arthritis may be an unusual but apparently not a rare sequel to such injury, when implantation occurs near a joint. In this case report, osseous changes were not seen by plain x-rays. Magnetic resonance imaging (MRI) was used to expose the more salient features of both soft tissue and bone changes of black sea urchin puncture injury 30 months after penetration. In all likelihood, this type of injury may be more common than the existing literature at present suggests. It is believed to be the first reported case in this part of the world as well as the first MRI study describing this type of joint pathology. Local and systemic reactions to puncture injuries from sea urchin spines have been described previously. These may range from mild, local irritation lasting a few days to granuloma formation, infection and on occasions systemic illness. The sea urchin spines are composed of calcium carbonate with proteinaceous covering. The covering tends to cause immune reactions of variable presentation. There are only a handful of reported cases with sea urchin stings on record, none of them from the Red Sea. However, this condition is probably more common than is thought and can present difficulty in diagnosis. In this case report, the inflammation responded well to heat treatment, mobilization and manipulation of the joint in its post acute and chronic stages. As some subtle changes in soft tissues and the changes in bone were not seen either on plain x-rays or ultrasound scan, gadolinium-enhanced MRI was used to unveil the marked changes in the joint. PMID:10689244

  20. An organized start to implant-supported prosthesis

    PubMed Central

    Karthigeyan, Suma; Ali, Seyed Ashraff; Mohan, Kalarani; Deivanai, Mangala

    2013-01-01

    Various treatment options are available for rehabilitating the complete edentulous patients with implants. However, due consideration for the prosthesis is not given prior to implant surgery. This can result in implant being placed in locations that do not provide the best esthetic and functional result. Incorrect implant localization and angle are the primary cause of non-axial loading and may contribute to loss of Osseo-integration. For predictable outcome, the treatment should begin with visualizing the end result. A step-wise pre-implant surgery evaluation is necessary to achieve the objectives. This is a case report of a completely edentulous patient who was treated with fixed implant prosthesis following various steps in the pre-implant surgery evaluation. PMID:23853462

  1. MRI and MRS of human brain tumors.

    PubMed

    Hou, Bob L; Hu, Jiani

    2009-01-01

    The purpose of this chapter is to provide an introduction to magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) of human brain tumors, including the primary applications and basic terminology involved. Readers who wish to know more about this broad subject should seek out the referenced books (1. Tofts (2003) Quantitative MRI of the brain. Measuring changes caused by disease. Wiley; Bradley and Stark (1999) 2. Magnetic resonance imaging, 3rd Edition. Mosby Inc; Brown and Semelka (2003) 3. MRI basic principles and applications, 3rd Edition. Wiley-Liss) or reviews (4. Top Magn Reson Imaging 17:127-36, 2006; 5. JMRI 24:709-724, 2006; 6. Am J Neuroradiol 27:1404-1411, 2006).MRI is the most popular means of diagnosing human brain tumors. The inherent difference in the magnetic resonance (MR) properties of water between normal tissues and tumors results in contrast differences on the image that provide the basis for distinguishing tumors from normal tissues. In contrast to MRI, which provides spatial maps or images using water signals of the tissues, proton MRS detects signals of tissue metabolites. MRS can complement MRI because the observed MRS peaks can be linked to inherent differences in biochemical profiles between normal tissues and tumors.The goal of MRI and MRS is to characterize brain tumors, including tumor core, edge, edema, volume, types, and grade. The commonly used brain tumor MRI protocol includes T2-weighted images and T1-weighted images taken both before and after the injection of a contrast agent (typically gadolinium: Gd). The commonly used MRS technique is either point-resolved spectroscopy (PRESS) or stimulated echo acquisition mode (STEAM). PMID:19381963

  2. Trends in Cochlear Implants

    PubMed Central

    Zeng, Fan-Gang

    2004-01-01

    More than 60,000 people worldwide use cochlear implants as a means to restore functional hearing. Although individual performance variability is still high, an average implant user can talk on the phone in a quiet environment. Cochlear-implant research has also matured as a field, as evidenced by the exponential growth in both the patient population and scientific publication. The present report examines current issues related to audiologic, clinical, engineering, anatomic, and physiologic aspects of cochlear implants, focusing on their psychophysical, speech, music, and cognitive performance. This report also forecasts clinical and research trends related to presurgical evaluation, fitting protocols, signal processing, and postsurgical rehabilitation in cochlear implants. Finally, a future landscape in amplification is presented that requires a unique, yet complementary, contribution from hearing aids, middle ear implants, and cochlear implants to achieve a total solution to the entire spectrum of hearing loss treatment and management. PMID:15247993

  3. MRI-Related Heating near Deep Brain Stimulation Electrodes: More Data Are Needed

    PubMed Central

    Gupte, Akshay A.; Shrivastava, Devashish; Spaniol, Maggie A.; Abosch, Aviva

    2011-01-01

    Magnetic resonance imaging (MRI) of patients with implanted deep brain stimulation (DBS) devices poses a challenge for healthcare providers. As a consequence of safety concerns about magnetic field interactions with the device, induced electrical currents and thermal damage due to radiofrequency heating, a number of stringent guidelines have been proposed by the device manufacturer. Very few detailed investigations of these safety issues have been published to date, and the stringent manufacturer guidelines have gone unchallenged, leading some hospitals and imaging centers around the world to ban or restrict the use of MRI in DBS patients. The purpose of this review is to stimulate research towards defining appropriate guidelines for the use of MRI in patients with DBS. Additionally, this review is intended to help healthcare providers and researchers make sound clinical judgments about the use of MRI in the setting of implanted DBS devices. PMID:21494064

  4. Evaluation of implant sonication as a diagnostic tool in implant-associated infections.

    PubMed

    Dapunt, Ulrike; Lehner, Burkhard; Burckhardt, Irene; Zimmermann, Stefan; Hänsch, Gertrud M; Ewerbeck, Volker

    2014-01-01

    Infections of implants pose a severe problem in the field of orthopedic surgery, because they can cause bone degradation with subsequent loosening of the implant. The discrimination between septic implant loosening and aseptic loosening can be a challenge, and hence novel diagnostic methods have been introduced to improve the detection of bacteria. Because a major problem is their firm adherence to implants due to biofilm formation, sonication has been introduced, followed by identification of bacteria by culture or genetic methods. In this study, we compared the results obtained after sonication pretreatment with those of microbiological testing of tissue samples and histopathological evaluation of the same tissue. Furthermore, we related the results obtained following sonication to the clinical diagnosis of septic or aseptic implant loosening, respectively. Sonication of explanted devices also enhances the likelihood of detecting bacterial growth in patients who were considered "aseptic" based on the clinical evaluation. PMID:25199070

  5. MRI Mode Programming for Safe Magnetic Resonance Imaging in Patients With a Magnetic Resonance Conditional Cardiac Device.

    PubMed

    Nakai, Toshiko; Kurokawa, Sayaka; Ikeya, Yukitoshi; Iso, Kazuki; Takahashi, Keiko; Sasaki, Naoko; Ashino, Sonoko; Okubo, Kimie; Okumura, Yasuo; Kunimoto, Satoshi; Watanabe, Ichiro; Hirayama, Atsushi

    2016-01-01

    Although diagnostically indispensable, magnetic resonance imaging (MRI) has been, until recently, contraindicated in patients with an implantable cardiac device. MR conditional cardiac devices are now widely used, but the mode programming needed for safe MRI has yet to be established. We reviewed the details of 41 MRI examinations of patients with a MR conditional device. There were no associated adverse events. However, in 3 cases, paced beats competed with the patient's own beats during the MRI examination. We describe 2 of the 3 specific cases because they illustrate these potentially risky situations: a case in which the intrinsic heart rate increased and another in which atrial fibrillation occurred. Safe MRI in patients with an MR conditional device necessitates detailed MRI mode programming. The MRI pacing mode should be carefully and individually selected. PMID:26973263

  6. Correction of MRI-induced geometric distortions in whole-body small animal PET-MRI

    SciTech Connect

    Frohwein, Lynn J. Schäfers, Klaus P.; Hoerr, Verena; Faber, Cornelius

    2015-07-15

    Purpose: The fusion of positron emission tomography (PET) and magnetic resonance imaging (MRI) data can be a challenging task in whole-body PET-MRI. The quality of the registration between these two modalities in large field-of-views (FOV) is often degraded by geometric distortions of the MRI data. The distortions at the edges of large FOVs mainly originate from MRI gradient nonlinearities. This work describes a method to measure and correct for these kind of geometric distortions in small animal MRI scanners to improve the registration accuracy of PET and MRI data. Methods: The authors have developed a geometric phantom which allows the measurement of geometric distortions in all spatial axes via control points. These control points are detected semiautomatically in both PET and MRI data with a subpixel accuracy. The spatial transformation between PET and MRI data is determined with these control points via 3D thin-plate splines (3D TPS). The transformation derived from the 3D TPS is finally applied to real MRI mouse data, which were acquired with the same scan parameters used in the phantom data acquisitions. Additionally, the influence of the phantom material on the homogeneity of the magnetic field is determined via field mapping. Results: The spatial shift according to the magnetic field homogeneity caused by the phantom material was determined to a mean of 0.1 mm. The results of the correction show that distortion with a maximum error of 4 mm could be reduced to less than 1 mm with the proposed correction method. Furthermore, the control point-based registration of PET and MRI data showed improved congruence after correction. Conclusions: The developed phantom has been shown to have no considerable negative effect on the homogeneity of the magnetic field. The proposed method yields an appropriate correction of the measured MRI distortion and is able to improve the PET and MRI registration. Furthermore, the method is applicable to whole-body small animal

  7. Cochlear re-implantation: lessons learnt and the way ahead.

    PubMed

    Patnaik, Uma; Sikka, Kapil; Agarwal, Shivani; Kumar, Rakesh; Thakar, Alok; Sharma, Suresh C

    2016-06-01

    Conclusion A cochlear re-implantation procedure is undesirable; however, the cochlear implant surgeon may have to perform a re-implantation procedure occasionally for various reasons. Following standard techniques, implant performance comparable with primary implantation may be achieved. Objective To study the causes and outcomes of cochlear re-implantation in an Asian Indian population. Study design Retrospective analysis of clinical charts over an 18-year period with prospective follow-up of patients. Methods The charts of 534 patients, who underwent cochlear implant, at an Otorhinolaryngology institutional Centre, from January 1997 to January 2015 were studied. Of these, the charts of 18 patients who underwent cochlear re-implantation were studied. The causes and audiological and speech outcomes were analysed. Results Eighteen patients (3.4%) underwent cochlear re-implantation for various reasons. The commonest indication was device failure in seven patients (39%), followed by electrode extrusion in five (28%), trauma in three (11%), electrode migration in two (11%) and improper electrode placement in one (6%) patient. The audiological performance tests and speech tests either remained the same or improved from those achieved for patients undergoing primary implantation, in 87% patients. PMID:26898701

  8. Silicone breast implant materials.

    PubMed

    Daniels, A U

    2012-01-01

    This opinion article has been written on request because of the recent public controversy over silicone breast implants produced by a now-defunct company, Poly Implant Prosthese (PIP) in France. More than 300,000 PIP devices have been implanted. The purposes of my article are to (1.) provide a general overview of silicone breast implant materials, (2.) to describe the general safety of these materials as reported to date, and (3.) to summarise current publicly available information about these aspects of the PIP prostheses. The materials covered are the silicone rubber from which the implant shells are made and the silicone gel used to fill the shell. The materials safety issues are biocompatibility (especially of the gel) and biodurability of the shell. The literature reviewed indicates that biocompatibility is not an issue with other current generation implants. However, biodurability is. A rough estimate of implant shell rupture rate is ~10+% at 10 years. Information is still emerging about the PIP implants. Initial regulatory disclosures suggest the PIP implants may have both biocompatibility and biodurability problems. They also suggest that PIP implants may have been produced using silicone materials not certified as medical grade. Governmental health and regulatory agencies are just now in the process of deciding what actions should be taken to protect patients. PMID:22826101

  9. Bolus-tracking MRI with a simultaneous T1- and T2*-measurement.

    PubMed

    Sourbron, S; Heilmann, M; Biffar, A; Walczak, C; Vautier, J; Volk, A; Peller, M

    2009-09-01

    The aim of this study was to propose and evaluate a methodology to analyze simultaneously acquired T2*-weighted dynamic susceptibility contrast (DSC) MRI and T(1)-weighted dynamic contrast enhanced (DCE) MRI data. Two generalized models of T2*-relaxation are proposed to account for tracer leakage, and a two-compartment exchange model is used to separate tracer in intra- and extravascular spaces. The methods are evaluated using data extracted from ROIs in three mice with subcutaneously implanted human colorectal tumors. Comparing plasma flow values obtained from DCE-MRI and DSC-MRI data defines a practical experimental paradigm to measure T2*-relaxivities, and reveals a factor of 15 between values in tissue and blood. Comparing mean transit time values obtained from DCE-MRI and DSC-MRI without leakage correction, indicates a significant reduction of susceptibility weighting in DSC-MRI during tracer leakage. A one-parameter gradient correction model provides a good approximation for this susceptibility loss, but redundancy of the parameter limits the practical potential of this model for DSC-MRI. Susceptibility loss is modeled more accurately with a variable T2*-relaxivity, which allows to extract new parameters that cannot be derived from DSC-MRI or DCE-MRI alone. They reflect the cellular and vessel geometry, and thus may lead to a more complete characterization of tissue structure. PMID:19585599

  10. Immediate implant post-surgical complications.

    PubMed

    Ibbott, C G; Oles, R D

    1995-03-01

    Immediate surgical implants provide a convenient means of replacing missing teeth without requiring hard tissue reduction of restoration-free potential fixed partial denture abutments. Although the procedure is described as "predictable," complications and failures do occur. This report presents four cases of immediate implant complications and their management, and discusses possible causes of the untoward results. Careful pre-operative planning, adequate surgical technique and post-surgical management, timely and suitable loading, and meticulous hygiene maintenance can serve to minimize implant complications and failures. The prospective immediate implant patient must be provided with sufficient information to allow informed consent to be given. Minimal requirements are a description of the procedures in terms the patient can understand, an explanation of potential risks and complications, and adequate disclosure of information about alternative therapies. PMID:7773849

  11. [Bone Conduction and Active Middle Ear Implants].

    PubMed

    Volkenstein, S; Thomas, J P; Dazert, S

    2016-05-01

    The majority of patients with moderate to severe hearing loss can be supplied with conventional hearing aids depending on severity and cause for hearing loss in a satisfying way. However, some patients either do not benefit enough from conventional hearing aids or cannot wear them due to inflammatory reactions and chronic infections of the external auditory canal or due to anatomical reasons. For these patients there are fully- and semi-implantable middle ear and bone conduction implants available. These devices either directly stimulate the skull (bone conduction devices), middle ear structures (active middle ear implants) or the cochlea itself (direct acoustic stimulation). Patients who failed surgical hearing rehabilitation or do not benefit from conventional hearing aids may achieve a significant better speech understanding and tremendous improvement in quality of life by implantable hearing devices with careful attention to the audiological and anatomical indication criteria. PMID:27135430

  12. Economic Analysis of Screening Strategies for Rupture of Silicone Gel Breast Implants

    PubMed Central

    Chung, Kevin C.; Malay, Sunitha; Shauver, Melissa J.; Kim, H. Myra

    2012-01-01

    Background In 2006, the U.S. Food and Drug Administration (FDA) recommended screening of all women with silicone gel breast implants with magnetic resonance imaging (MRI) three years after implantation and every two years thereafter to assess their integrity. The cost for these serial examinations over the lifetime of the breast implants is an added burden to insurance payers and to women. We perform an economic analysis to determine the most optimal screening strategies by considering the diagnostic accuracy of the screening tests, the costs of the tests and subsequent implant removal. Methods We determined aggregate/pooled values for sensitivity and specificity of the screening tests ultrasound (US) and MRI in detecting silicone breast implant ruptures from the data obtained from published literature. We compiled costs, based on Medicare reimbursements for 2011, for the following elements: imaging modalities, anesthesia and 3 surgical treatment options for detected ruptures. We used decision tree to compare three alternate screening strategies of US only, MRI only and US followed by MRI in asymptomatic and symptomatic women. Results The cost per rupture of screening and management of rupture with US in asymptomatic women was $1,090, whereas in symptomatic women it was $1,622. Similar cost for MRI in asymptomatic women was $2,067, whereas in symptomatic women it was $2,143. Similar cost for US followed by MRI in asymptomatic women was $637, whereas in symptomatic women it was $2,908. Conclusion Screening with US followed by MRI was optimal for asymptomatic women and screening with US was optimal for symptomatic women. PMID:22743887

  13. Towards MRI microarrays.

    PubMed

    Hall, Andrew; Mundell, Victoria J; Blanco-Andujar, Cristina; Bencsik, Martin; McHale, Glen; Newton, Michael I; Cave, Gareth W V

    2010-04-14

    Superparamagnetic iron oxide nanometre scale particles have been utilised as contrast agents to image staked target binding oligonucleotide arrays using MRI to correlate the signal intensity and T(2)* relaxation times in different NMR fluids. PMID:20379545

  14. Sinus MRI scan

    MedlinePlus

    ... Thomsen HS, Reimer P. Intravascular contrast media for radiology, CT, and MRI. In: Adam A, Dixon AK, ... JH, Schaefer-Prokop CM, eds. Grainger & Allison's Diagnostic Radiology: A Textbook of Medical Imaging . 6th ed. New ...

  15. Knee MRI scan

    MedlinePlus

    ... magnetic resonance imaging) scan uses energy from strong magnets to create pictures of the knee joint and ... in your eyes) Because the MRI contains strong magnets, metal objects are not allowed into the room ...

  16. Leg MRI scan

    MedlinePlus

    ... resonance imaging) scan of the leg uses strong magnets to create pictures of the leg. This may ... in your eyes) Because the MRI contains strong magnets, metal objects are not allowed into the room ...

  17. Cervical MRI scan

    MedlinePlus

    ... magnetic resonance imaging) scan uses energy from strong magnets to create pictures of the part of the ... in your eyes) Because the MRI contains strong magnets, metal objects are not allowed into the room ...

  18. Lumbar MRI scan

    MedlinePlus

    ... may need a lumbar MRI if you have: Low back pain that does not get better after treatment Leg ... spine Injury or trauma to the lower spine Low back pain and a history or signs of cancer Multiple ...

  19. MRI (Magnetic Resonance Imaging)

    MedlinePlus

    ... some MRI exams, intravenous (IV) drugs, such as gadolinium-based contrast agents (GBCAs) are used to change the contrast of the MR image. Gadolinium-based contrast agents are rare earth metals that ...

  20. MRI of the Breast

    MedlinePlus

    ... as a supplemental tool to breast screening with mammography or ultrasound. It may be used to screen ... following diagnosis, or further evaluate abnormalities seen on mammography. Breast MRI does not use ionizing radiation, and ...

  1. Shoulder MRI scan

    MedlinePlus

    ... an imaging test that uses energy from powerful magnets and to create pictures of the shoulder area. ... in your eyes) Because the MRI contains strong magnets, metal objects are not allowed in the room ...

  2. Larynx: implants and stents

    PubMed Central

    Sittel, Christian

    2011-01-01

    In the human larynx, implants a primarily used for the correction of glottis insufficiency. In a broader sense laryngeal stents may be considered as implants as well. Laryngeal implants can be differentiated into injectable and solid. The most important representatives of both groups are discussed in detail along with the respective technique of application. Laryngeal stents are primarily used perioperatively. Different types and their use are presented. PMID:22073097

  3. Implants in adolescents

    PubMed Central

    Shah, Rohit A.; Mitra, Dipika K.; Rodrigues, Silvia V.; Pathare, Pragalbha N.; Podar, Rajesh S.; Vijayakar, Harshad N.

    2013-01-01

    Implants have gained tremendous popularity as a treatment modality for replacement of missing teeth in adults. There is extensive research present on the use of implants in adults, but there is a dearth of data available on the same in adolescents. The treatment planning and execution of implant placement in adolescents is still in its infancy. This review article is an attempt to bring together available literature. PMID:24174743

  4. Unusual cause of acute low-back pain: sudden annulus fibrosus rupture.

    PubMed

    Ozer, Ali Fahir; Oktenoglu, Tunc; Sasani, Mehdi; Kaner, Tuncay; Ercelen, Omur; Canbulat, Nazan

    2012-05-01

    Low-back pain is a common problem in neu-rosurgery practice, and an algorithm has been developed for assessing these cases. However, one subgroup of these patients shares several clinical features and these individuals are not easy to categorize and diagnose. We present our observations for 8 of these patients, individuals with low-back pain caused by atypical annulus fibrosus rupture (AAR). The aim of this study is to show the consequences of overlooked annular tears on acute onset of low back pain. Eight patients with acute-onset severe low-back pain were admitted. Physical examinations were normal and each individual was examined neurologically and assessed with neuroradiologic studies [plain x-rays, magnetic resonance imaging (MRI), discography and computed tomography (CT) discography]. AAR was ultimately diagnosed with provocative discography. In all cases, MRI showed a healthy disc or mild degeneration, whereas discography and CT discography demonstrated disc disease. Anterior interbody cage implantation was performed in 3 of the 8 cases and posterior dynamic stabilization was carried out in 3 cases. The other 2 individuals refused surgery, and we were informed that one of them developed disc herniation at the affected level 1 year after our diagnosis. Clinical and radiological outcomes were evaluated. In cases where AAR is suspected, MRI, discography, and CT discography should be performed in addition to routine neuroradiologic studies. PMID:22802990

  5. Pre-, Intra- and Post-Operative Imaging of Cochlear Implants.

    PubMed

    Vogl, T J; Tawfik, A; Emam, A; Naguib, N N N; Nour-Eldin, A; Burck, I; Stöver, T

    2015-11-01

    The purpose of this review is to present essential imaging aspects in patients who are candidates for a possible cochlear implant as well as in postsurgical follow-up. Imaging plays a major role in providing information on preinterventional topography, variations and possible infections. Preoperative imaging using DVT, CT, MRI or CT and MRI together is essential for candidate selection, planning of surgical approach and exclusion of contraindications like the complete absence of the cochlea or cochlear nerve, or infection. Relative contraindications are variations of the cochlea and vestibulum. Intraoperative imaging can be performed by fluoroscopy, mobile radiography or DVT. Postoperative imaging is regularly performed by conventional X-ray, DVT, or CT. In summary, radiological imaging has its essential role in the pre- and post-interventional period for patients who are candidates for cochlear implants. PMID:26327670

  6. Raman scattering of hydrogen- and deuterium-implanted cadmium fluoride

    SciTech Connect

    Stutzmann, M.; Tatarkiewicz, J.

    1987-11-01

    The effects of proton and deuteron implantation on the Raman spectra of CdF/sub 2/ crystals have been investigated. It is found that Raman scattering can provide a quantitative measure for the structural damage caused by the implantation procedure. These results also elucidate the intrinsic or extrinsic origin of Raman peaks observed in semiconducting CdF/sub 2/.

  7. Protein composition alters in vivo resorption of PEG-based hydrogels as monitored by contrast-enhanced MRI.

    PubMed

    Berdichevski, Alexandra; Shachaf, Yonatan; Wechsler, Roni; Seliktar, Dror

    2015-02-01

    We report on the use of magnetic resonance imaging (MRI)-based non-invasive monitoring to document the role of protein adjuvants in hydrogel implant integration in vivo. Polyethylene glycol (PEG) hydrogels were formed with different protein constituents, including albumin, fibrinogen and gelatin. The hydrogels were designed to exhibit similar material properties, including modulus, swelling and hydrolytic degradation kinetics. The in vivo resorption properties of these PEG-based hydrogels, which contained a tethered gadolinium contrast agent, were characterized by MRI and histology, and compared to their in vitro characteristics. MRI data revealed that PEG-Albumin implants remained completely intact throughout the experiments, PEG-Fibrinogen implants lost about 10% of their volume and PEG-Gelatin implants underwent prominent swelling and returned to their initial volume by day 25. Fully synthetic PEG-diacrylate (PEG-DA) control hydrogels lost about half of their volume after 25 days in vivo. Transverse MRI cross-sections of the implants revealed distinct mechanisms of the hydrogel's biodegradation: PEG-Fibrinogen and PEG-Albumin underwent surface erosion, whereas PEG-Gelatin and PEG-DA hydrogels mainly underwent bulk degradation. Histological findings substantiated the MRI data and demonstrated significant cellular response towards PEG-DA and PEG-Gelatin scaffolds with relatively low reaction towards PEG-Fibrinogen and PEG-Albumin hydrogels. These findings demonstrate that PEG-protein hydrogels can degrade via a different mechanism than PEG hydrogels, and that this difference can be linked to a reduced foreign body response. PMID:25542788

  8. Cervical MRI scan

    MedlinePlus

    ... you have: Brain aneurysm clips Certain types of artificial heart valves Heart defibrillator or pacemaker Inner ear (cochlear) implants Kidney disease or dialysis (you may not be able to ... artificial joints Certain types of vascular stents Worked with ...

  9. Peri-implant diseases: Consensus Report of the Sixth European Workshop on Periodontology.

    PubMed

    Lindhe, Jan; Meyle, Joerg

    2008-09-01

    Issues related to peri-implant disease were discussed. It was observed that the most common lesions that occur, i.e. peri-implant mucositis and peri-implantitis are caused by bacteria. While the lesion of peri-implant mucositis resides in the soft tissues, peri-implantitis also affects the supporting bone. Peri-implant mucositis occurs in about 80% of subjects (50% of sites) restored with implants, and peri-implantitis in between 28% and 56% of subjects (12-40% of sites). A number of risk indicators were identified including (i) poor oral hygiene, (ii) a history of periodontitis, (iii) diabetes and (iv) smoking. It was concluded that the treatment of peri-implant disease must include anti-infective measures. With respect to peri-implant mucositis, it appeared that non-surgical mechanical therapy caused the reduction in inflammation (bleeding on probing) but also that the adjunctive use of antimicrobial mouthrinses had a positive effect. It was agreed that the outcome of non-surgical treatment of peri-implantitis was unpredictable. The primary objective of surgical treatment in peri-implantitis is to get access to the implant surface for debridement and decontamination in order to achieve resolution of the inflammatory lesion. There was limited evidence that such treatment with the adjunctive use of systemic antibiotics could resolve a number of peri-implantitis lesions. There was no evidence that so-called regenerative procedures had additional beneficial effects on treatment outcome. PMID:18724855

  10. Biocompatible implants and methods of making and attaching the same

    DOEpatents

    Rowley, Adrian P; Laude, Lucien D; Humayun, Mark S; Weiland, James D; Lotfi, Atoosa; Markland, Jr., Francis S

    2014-10-07

    The invention provides a biocompatible silicone implant that can be securely affixed to living tissue through interaction with integral membrane proteins (integrins). A silicone article containing a laser-activated surface is utilized to make the implant. One example is an implantable prosthesis to treat blindness caused by outer retinal degenerative diseases. The device bypasses damaged photoreceptors and electrically stimulates the undamaged neurons of the retina. Electrical stimulation is achieved using a silicone microelectrode array (MEA). A safe, protein adhesive is used in attaching the MEA to the retinal surface and assist in alleviating focal pressure effects. Methods of making and attaching such implants are also provided.