WorldWideScience

Sample records for active mri implants

  1. Safety of active implantable devices during MRI examinations: a finite element analysis of an implantable pump.

    Science.gov (United States)

    Büchler, Philippe; Simon, Anne; Burger, Jürgen; Ginggen, Alec; Crivelli, Rocco; Tardy, Yanik; Luechinger, Roger; Olsen, Sigbjørn

    2007-04-01

    The goal of this study was to propose a general numerical analysis methodology to evaluate the magnetic resonance imaging (MRI)-safety of active implants. Numerical models based on the finite element (FE) technique were used to estimate if the normal operation of an active device was altered during MRI imaging. An active implanted pump was chosen to illustrate the method. A set of controlled experiments were proposed and performed to validate the numerical model. The calculated induced voltages in the important electronic components of the device showed dependence with the MRI field strength. For the MRI radiofrequency fields, significant induced voltages of up to 20 V were calculated for a 0.3T field-strength MRI. For the 1.5 and 3.0OT MRIs, the calculated voltages were insignificant. On the other hand, induced voltages up to 11 V were calculated in the critical electronic components for the 3.0T MRI due to the gradient fields. Values obtained in this work reflect to the worst case situation which is virtually impossible to achieve in normal scanning situations. Since the calculated voltages may be removed by appropriate protection circuits, no critical problems affecting the normal operation of the pump were identified. This study showed that the proposed methodology helps the identification of the possible incompatibilities between active implants and MR imaging, and can be used to aid the design of critical electronic systems to ensure MRI-safety.

  2. Finite volume analysis of temperature effects induced by active MRI implants: 2. Defects on active MRI implants causing hot spots

    Directory of Open Access Journals (Sweden)

    Grönemeyer Dietrich HW

    2006-05-01

    Full Text Available Abstract Background Active magnetic resonance imaging implants, for example stents, stent grafts or vena cava filters, are constructed as wireless inductively coupled transmit and receive coils. They are built as a resonator tuned to the Larmor frequency of a magnetic resonance system. The resonator can be added to or incorporated within the implant. This technology can counteract the shielding caused by eddy currents inside the metallic implant structure. This may allow getting diagnostic information of the implant lumen (in stent stenosis or thrombosis for example. The electro magnetic rf-pulses during magnetic resonance imaging induce a current in the circuit path of the resonator. A by material fatigue provoked partial rupture of the circuit path or a broken wire with touching surfaces can set up a relatively high resistance on a very short distance, which may behave as a point-like power source, a hot spot, inside the body part the resonator is implanted to. This local power loss inside a small volume can reach ¼ of the total power loss of the intact resonating circuit, which itself is proportional to the product of the resonator volume and the quality factor and depends as well from the orientation of the resonator with respect to the main magnetic field and the imaging sequence the resonator is exposed to. Methods First an analytical solution of a hot spot for thermal equilibrium is described. This analytical solution with a definite hot spot power loss represents the worst case scenario for thermal equilibrium inside a homogeneous medium without cooling effects. Starting with this worst case assumptions additional conditions are considered in a numerical simulation, which are more realistic and may make the results less critical. The analytical solution as well as the numerical simulations use the experimental experience of the maximum hot spot power loss of implanted resonators with a definite volume during magnetic resonance imaging

  3. On the Procedures for the Demonstration of the RF Safety of Active and Passive Implants in MRI Environments

    Institute of Scientific and Technical Information of China (English)

    Eugenia CABOT; Maria CABANES-SEMPERE; Niels KUSTER

    2016-01-01

    As a diagnostic method, magnetic resonance imaging (MRI) is not allowed to be used in patients with medical implants, including both active implants (such as cardiac deifbrillators or deep brain stimulators) and passive implants (such as orthopedics implants and support). MRI imaging scanning can produce magnetic ifelds, which will produce concentrated electromagnetic induction on metal edges of the implants, such as electrodes. The magnetic ifeld can also signiifcantly increase the temperature of surrounding tissues. Besides, the currents and voltage produced by active implants when exposed to MRI scanning can lead to damage and malfunction of pulse generators. Therefore, patients with medical implants cannot receive MRI as a diagnostic method. This safety protocol prevents a large group of patients from receiving MRI diagnosis. This leads to the conclusion that the safety evaluation of implants under MRI environment requires the combination of accurate data analysis and experimental techniques so as to establish the standard testing program.

  4. MRI of orbital hydroxyapatite implants

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    Flanders, A.E. [Dept. of Radiology, Thomas Jefferson Univ. Hospital, Philadelphia, PA (United States); De Potter, P. [Dept. of Ophthalmology, Wills Eye Inst., Philadelphia, PA (United States); Rao, V.M. [Dept. of Radiology, Thomas Jefferson Univ. Hospital, Philadelphia, PA (United States); Tom, B.M. [Dept. of Radiology, Thomas Jefferson Univ. Hospital, Philadelphia, PA (United States); Shields, C.L. [Dept. of Ophthalmology, Wills Eye Inst., Philadelphia, PA (United States); Shields, J.A. [Dept. of Ophthalmology, Wills Eye Inst., Philadelphia, PA (United States)

    1996-04-01

    Our aim was to use MRI for the postsurgical assessment of a new form of integrated orbital implant composed of a porous calcium phosphate hydroxyapatite substrate. We studied ten patients 24-74 years of age who underwent enucleation and implantation of a hydroxyapatite ball; 5-13 months after surgery, each patient was examined by spin-echo MRI, with fat suppression and gadolinium enhancement. Fibrovascular ingrowth was demonstrated in all ten patients as areas of enhancement at the periphery of the hydroxyapatite sphere that extended to the center to a variable degree. The radiologist should aware of the MRI appearances of the coralline hydroxyapatite orbital implant since it is now widely used following enucleation. MRI is a useful means to determine successful incorporation of the substrate into the orbital tissues. The normal pattern of contrast enhancement should not be mistaken for recurrent tumor or infection. (orig.)

  5. Finite volume analysis of temperature effects induced by active MRI implants with cylindrical symmetry: 1. Properly working devices

    Directory of Open Access Journals (Sweden)

    Schnorr Jörg

    2005-04-01

    Full Text Available Abstract Background Active Magnetic Resonance Imaging implants are constructed as resonators tuned to the Larmor frequency of a magnetic resonance system with a specific field strength. The resonating circuit may be embedded into or added to the normal metallic implant structure. The resonators build inductively coupled wireless transmit and receive coils and can amplify the signal, normally decreased by eddy currents, inside metallic structures without affecting the rest of the spin ensemble. During magnetic resonance imaging the resonators generate heat, which is additional to the usual one described by the specific absorption rate. This induces temperature increases of the tissue around the circuit paths and inside the lumen of an active implant and may negatively influence patient safety. Methods This investigation provides an overview of the supplementary power absorbed by active implants with a cylindrical geometry, corresponding to vessel implants such as stents, stent grafts or vena cava filters. The knowledge of the overall absorbed power is used in a finite volume analysis to estimate temperature maps around different implant structures inside homogeneous tissue under worst-case assumptions. The "worst-case scenario" assumes thermal heat conduction without blood perfusion inside the tissue around the implant and mostly without any cooling due to blood flow inside vessels. Results The additional power loss of a resonator is proportional to the volume and the quality factor, as well as the field strength of the MRI system and the specific absorption rate of the applied sequence. For properly working devices the finite volume analysis showed only tolerable heating during MRI investigations in most cases. Only resonators transforming a few hundred mW into heat may reach temperature increases over 5 K. This requires resonators with volumes of several ten cubic centimeters, short inductor circuit paths with only a few 10 cm and a quality

  6. MRI of breast implant-related complications

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Seung Hae; Kook, Shin Ho; Kim, Jong Wook; Ahn, Sung Yul; Cha, Dong Sup; Whang, Kwi Whan; Pae, Won Kil; Park, Yong Lai; Lee, Young Uk; Park, Hae Won; Kim, Myung Sook [Kangbuk Samsung Hospital, Seoul (Korea, Republic of)

    1998-06-01

    The purpose of this study is to assess the usefulness of MRI in the preoperative diagnosis of breast implant-related complications. Thirty four breast implants in 17 patients were examined. Eight breasts had a history of repeated surgery due to rupture and in eight others, simultaneous interstitial silicone injection had been performed. MR images of the 34 implants were prospectively analyzed for implant-related complications, without prior clinical information, and the findings were compared with the results of surgery. MRI was an effective and useful method for the preoperative evaluation of implant-related complications; degree of contracture was successfully predicted. (author). 18 refs., 2 tabs., 5 figs.

  7. Finite volume analysis of temperature effects induced by active MRI implants with cylindrical symmetry: 1. Properly working devices

    OpenAIRE

    Schnorr Jörg; Vollmann Wolfgang; Busch Martin HJ; Grönemeyer Dietrich HW

    2005-01-01

    Abstract Background Active Magnetic Resonance Imaging implants are constructed as resonators tuned to the Larmor frequency of a magnetic resonance system with a specific field strength. The resonating circuit may be embedded into or added to the normal metallic implant structure. The resonators build inductively coupled wireless transmit and receive coils and can amplify the signal, normally decreased by eddy currents, inside metallic structures without affecting the rest of the spin ensemble...

  8. Synthetic hydroxyapatite orbital implants: a clinical and MRI evaluation.

    Science.gov (United States)

    Sarvananthan, N; Liddicoat, A J; Fahy, G T

    1999-04-01

    Coralline hydroxypatite orbital implants have been used since the 1980s. More recently, synthetic hydroxyapatite orbital implants have been used, in both primary and secondary orbital implantation surgery. The implant may be drilled and pegged, if required, after adequate vascularisation of the implant has occurred. In this study we evaluated the clinical results and vascularisation of synthetic hydroxyapatite orbital implants. Twelve consecutive patients who had synthetic hydroxyapaptite orbital implants were evaluated clinically and 8 of these patients had orbital magnetic resonance imaging (MRI) scans with intravenous gadolinium performed at least 9 months post-operatively to assess vascularisation of the implant. Six patients had primary orbital implants at the time of enucleation and 6 patients had secondary implants. No significant complications occurred following insertion of the synthetic hydroxyapatite orbital implants. All patients reported cosmetic satisfaction with the results of surgery. MRI scans revealed inhomogeneous enhancement in 3 of the 4 patients receiving primary implants. All patients with secondary implants and 1 patients who had a primary implant had moderate to large areas of poor enhancement in the implant. Synthetic hydroxyapatite implants gave good clinical results but variable vascularisation occurs, especially with secondary implants.

  9. MRI of active otosclerosis

    Energy Technology Data Exchange (ETDEWEB)

    Ziyeh, S. [Section of Neuroradiology, Universitaetsklinik Freiburg, Breisacherstrasse 64, D-79106 Freiburg (Germany); Berlis, A. [Section of Neuroradiology, Universitaetsklinik Freiburg, Breisacherstrasse 64, D-79106 Freiburg (Germany); Ross, U.H. [Department of Otolaryngology, Universitaetsklinik, Freiburg (Germany); Reinhardt, M.J. [Department of Nuclear Medicine, Universitaetsklinik, Freiburg (Germany); Schumacher, M. [Section of Neuroradiology, Universitaetsklinik Freiburg, Breisacherstrasse 64, D-79106 Freiburg (Germany)

    1997-06-01

    Our aim was to determine whether MRI reliably shows pathology in patients with active otosclerosis (otospongiosis). We studied five patients with clinical and audiometric signs of this disorder and positive findings on high-resolution CT and tympanocochlear scintigraphy. Contrast enhancement of otospongiotic lesions was found in all affected ears, and could be topographically related to demineralised otospongiotic foci on CT. In lesions in the lateral wall of the labyrinth MRI sometimes showed the pathology better than CT, where partial-volume effects could be troublesome. (orig.). With 3 figs., 1 tab.

  10. Scientists Design Heat-Activated Penis Implant

    Science.gov (United States)

    ... news/fullstory_162815.html Scientists Design Heat-Activated Penis Implant Device an improvement on current implants, researchers ... News) -- Doctors report that they have crafted a penis implant that becomes erect when heated. Dubbed by ...

  11. Magnet dislocation: an increasing and serious complication following MRI in patients with cochlear implants.

    Science.gov (United States)

    Hassepass, F; Stabenau, V; Arndt, S; Beck, R; Bulla, S; Grauvogel, T; Aschendorff, A

    2014-07-01

    Cochlear implantation (CI) represents the gold standard in the treatment of children born deaf and postlingually deafened adults. Initial magnetic resonance imaging (MRI) was contraindicated in CI users. Meanwhile, there are specific recommendations concerning MRI compatibility depending on the type of CI system and the device manufacturer. Some CI systems are even approved for MRI with the internal magnet left in place. The aim of this study was to analyze all magnet revision surgeries in CI patients at one CI center and the relationship to MRI scans over time. Between 2000 and 2013, a total of 2027 CIs were implanted. The number of magnet dislocation (MD) surgeries and their causes was assessed retrospectively. In total 12 cases of MD resulting from an MRI scan (0.59 %) were observed, accounting for 52.2 % of all magnetic revision surgeries. As per the labeling, it was considered safe to leave the internal magnet in place during MRI while following specific manufacturer recommendations: MRI intensity of 1.5 Tesla (T) and compression head bandage during examination. A compression head bandage in a 1.5 T MRI unit does not safely prevent MD and the related serious complications in CI recipients. We recommend a Stenvers view radiograph after MRI with the internal magnet in place for early identification of MD, at least in the case of pain during or after MRI examination. MRI in CI patients should be indicated with restraint and patients should be explicitly informed about the possible risks. Recommendations regarding MRI compatibility and the handling of CI patients issued with MRI for the most common CI systems are summarized. © Georg Thieme Verlag KG Stuttgart · New York.

  12. MRI induced torque and demagnetization in retention magnets for a bone conduction implant.

    Science.gov (United States)

    Jansson, Karl-Johan Fredén; Håkansson, Bo; Reinfeldt, Sabine; Taghavi, Hamidreza; Eeg-Olofsson, Måns

    2014-06-01

    Performing magnetic resonance imaging (MRI) examinations in patients who use implantable medical devices involve safety risks both for the patient and the implant. Hearing implants often use two permanent magnets, one implanted and one external, for the retention of the external transmitter coil to the implanted receiver coil to achieve an optimal signal transmission. The implanted magnet is subjected to both demagnetization and torque, magnetically induced by the MRI scanner. In this paper, demagnetization and a comparison between measured and simulated induced torque is studied for the retention magnet used in a bone conduction implant (BCI) system. The torque was measured and simulated in a uniform static magnetic field of 1.5 T. The magnetic field was generated by a dipole electromagnet and permanent magnets with two different types of coercive fields were tested. Demagnetization and maximum torque for the high coercive field magnets was 7.7% ± 2.5% and 0.20 ± 0.01 Nm, respectively and 71.4% ± 19.1% and 0.18 ± 0.01 Nm for the low coercive field magnets, respectively. The simulated maximum torque was 0.34 Nm, deviating from the measured torque in terms of amplitude, mainly related to an insufficient magnet model. The BCI implant with high coercive field magnets is believed to be magnetic resonance (MR) conditional up to 1.5 T if a compression band is used around the skull to fix the implant. This is not approved and requires further investigations, and if removal of the implant is needed, the surgical operation is expected to be simple.

  13. MRI assessment of thoracic stent grafts after emergency implantation in multi trauma patients: a feasibility study

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    Rasche, Volker [University Hospital Ulm, Department of Internal Medicine II, Ulm (Germany); University Hospital Ulm, University of Ulm, Department of Internal Medicine II, Ulm (Germany); Oberhuber, Alexander; Orend, Karl-Heinz [University Hospital Ulm, Department of Vascular and Thoracic Surgery, Ulm (Germany); Trumpp, Stephan [University Hospital Ulm, Department of Internal Medicine II, Ulm (Germany); University Hospital Ulm, Department of Vascular and Thoracic Surgery, Ulm (Germany); Bornstedt, Axel; Merkle, Nico; Rottbauer, Wolfgang [University Hospital Ulm, Department of Internal Medicine II, Ulm (Germany); Hoffmann, Martin [University Hospital Ulm, Department of Diagnostic and Interventional Radiology, Ulm (Germany)

    2011-07-15

    To evaluate the feasibility of MRI for static and dynamic assessment of the deployment of thoracic aortic stent grafts after emergency implantation in trauma patients. Twenty patients initially presenting with a rupture of the thoracic aorta were enrolled in this study. All patients underwent thoracic endovascular aortic repair (TEVAR). The deployment of the implanted stent graft was assessed by CTA and MRI, comprising the assessment of the aortic arch with and without contrast agent, and the assessment of the motion of the stent graft over the cardiac cycle. The stent graft geometry and motion over the cardiac cycle were assessable by MRI in all patients. Flow-mediated signal variations in areas of flow acceleration could be well visualised. No statistically significant differences in stent-graft diameters were observed between CT and MRI measurements. MRI appears to be a valuable tool for the assessment of thoracic stent grafts. It shows similar performance in the accurate assessment of stent-graft dimensions to the current gold standard CTA. Its capability of providing additional functional information and the lack of ionising radiation and nephrotoxic contrast agents may make MRI a valuable tool for monitoring patients after TEVAR. (orig.)

  14. MRI screening for silicone breast implant rupture: accuracy, inter- and intraobserver variability using explantation results as reference standard

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    Maijers, M.C.; Ritt, M.J.P.F. [VU University Medical Centre, Department of Plastic, Reconstructive and Hand Surgery, De Boelelaan 1117, PO Box 7057, Amsterdam (Netherlands); Niessen, F.B. [VU University Medical Centre, Department of Plastic, Reconstructive and Hand Surgery, De Boelelaan 1117, PO Box 7057, Amsterdam (Netherlands); Jan van Goyen Clinic, Department of Plastic Surgery, Amsterdam (Netherlands); Veldhuizen, J.F.H. [MRI Centre, Amsterdam (Netherlands); Manoliu, R.A. [MRI Centre, Amsterdam (Netherlands); VU University Medical Centre, Department of Radiology, Amsterdam (Netherlands)

    2014-06-15

    The recall of Poly Implant Prothese (PIP) silicone breast implants in 2010 resulted in large numbers of asymptomatic women with implants who underwent magnetic resonance imaging (MRI) screening. This study's aim was to assess the accuracy and interobserver variability of MRI screening in the detection of rupture and extracapsular silicone leakage. A prospective study included 107 women with 214 PIP implants who underwent explantation preceded by MRI. In 2013, two radiologists blinded for previous MRI findings or outcome at surgery, independently re-evaluated all MRI examinations. A structured protocol described the MRI findings. The ex vivo findings served as reference standard. In 208 of the 214 explanted prostheses, radiologists agreed independently about the condition of the implants. In five of the six cases they disagreed (2.6 %), but subsequently reached consensus. A sensitivity of 93 %, specificity of 93 %, positive predictive value of 77 % and negative predictive value of 98 % was found. The interobserver agreement was excellent (kappa value of 0.92). MRI has a high accuracy in diagnosing rupture in silicone breast implants. Considering the high kappa value of interobserver agreement, MRI appears to be a consistent diagnostic test. A simple, uniform classification, may improve communication between radiologist and plastic surgeon. (orig.)

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

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    Amro, H; Chetty, I; Gordon, J; Wen, N [Henry Ford Health System, Detroit, MI (United States)

    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.

  16. MRI evaluation of a new scaffold-based allogenic chondrocyte implantation for cartilage repair

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    Dhollander, A.A.M., E-mail: Aad.Dhollander@Ugent.b [Department of Orthopaedic Surgery and Traumatology, Ghent University Hospital, De Pintelaan 185, 1P5, B9000 Gent (Belgium); Huysse, W.C.J., E-mail: Wouter.Huysse@Ugent.b [Department of Radiology, Ghent University Hospital, De Pintelaan 185, -1K12 IB, B9000 Gent (Belgium); Verdonk, P.C.M., E-mail: pverdonk@yahoo.co [Department of Orthopaedic Surgery and Traumatology, Ghent University Hospital, De Pintelaan 185, 1P5, B9000 Gent (Belgium); Verstraete, K.L., E-mail: Koenraad.Verstraete@Ugent.b [Department of Radiology, Ghent University Hospital, De Pintelaan 185, -1K12 IB, B9000 Gent (Belgium); Verdonk, R., E-mail: Rene.Verdonk@Ugent.b [Department of Orthopaedic Surgery and Traumatology, Ghent University Hospital, De Pintelaan 185, 1P5, B9000 Gent (Belgium); Verbruggen, G., E-mail: Gust.Verbruggen@Ugent.b [Laboratory of Connective Tissue Biology, Department of Rheumatology, Ghent University Hospital, De Pintelaan 185, Ghent (Belgium); Almqvist, K.F., E-mail: Fredrik.Almqvist@Ugent.b [Department of Orthopaedic Surgery and Traumatology, Ghent University Hospital, De Pintelaan 185, 1P5, B9000 Gent (Belgium)

    2010-07-15

    Aim: The present study was designed to evaluate the implantation of alginate beads containing human mature allogenic chondrocytes for the treatment of symptomatic cartilage defects of the knee. MRI was used for the morphological analysis of cartilage repair. The correlation between MRI findings and clinical outcome was also studied. Methods: A biodegradable, alginate-based biocompatible scaffold containing human mature allogenic chondrocytes was used for the treatment of symptomatic chondral and osteochondral lesions in the knee. Twenty-one patients were prospectively evaluated with use of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and the Visual Analogue Scale (VAS) for pain preoperatively and at 3, 6, 9 and 12 months of follow-up. Of the 21 patients, 12 had consented to follow the postoperative MRI evaluation protocol. MRI data were analyzed based on the original MOCART (Magnetic Resonance Observation of Cartilage Repair Tissue) and modified MOCART scoring system. The correlation between the clinical outcome and MRI findings was evaluated. Results: A statistically significant clinical improvement became apparent after 6 months and patients continued to improve during the 12 months of follow-up. One of the two MRI scoring systems that were used, showed a statistically significant deterioration of the repair tissue at 1 year of follow-up. Twelve months after the operation complete filling or hypertrophy was found in 41.6%. Bone-marrow edema and effusion were seen in 41.7% and 25% of the study patients, respectively. We did not find a consistent correlation between the MRI criteria and the clinical results. Discussion: The present study confirmed the primary role of MRI in the evaluation of cartilage repair. Two MOCART-based scoring systems were used in a longitudinal fashion and allowed a practical and morphological evaluation of the repair tissue. However, the correlation between clinical outcome and MRI findings was poor. Further

  17. Wrong detection of ventricular fibrillation in an implantable cardioverter defibrillator caused by the movement near the MRI scanner bore.

    Science.gov (United States)

    Mattei, Eugenio; Censi, Federica; Triventi, Michele; Mancini, Matteo; Napolitano, Antonio; Genovese, Elisabetta; Cannata, Vittorio; Falsaperla, Rosaria; Calcagnini, Giovanni

    2015-01-01

    The static magnetic field generated by MRI systems is highly non-homogenous and rapidly decreases when moving away from the bore of the scanner. Consequently, the movement around the MRI scanner is equivalent to an exposure to a time-varying magnetic field at very low frequency (few Hz). For patients with an implanted cardiac stimulators, such as an implantable cardioverter/defibrillator (ICD), the movements inside the MRI environment may thus induce voltages on the loop formed by the leads of the device, with the potential to affect the behavior of the stimulator. In particular, the ICD's detection algorithms may be affected by the induced voltage and may cause inappropriate sensing, arrhythmia detections, and eventually inappropriate ICD therapy.We performed in-vitro measurements on a saline-filled humanshaped phantom (male, 170 cm height), equipped with an MRconditional ICD able to transmit in real-time the detected cardiac activity (electrograms). A biventricular implant was reproduced and the ICD was programmed in standard operating conditions, but with the shock delivery disabled. The electrograms recorded in the atrial, left and right ventricle channels were monitored during rotational movements along the vertical axis, in close proximity of the bore. The phantom was also equipped with an accelerometer and a magnetic field probe to measure the angular velocity and the magnetic field variation during the experiment. Pacing inhibition, inappropriate detection of tachyarrhythmias and of ventricular fibrillation were observed. Pacing inhibition began at an angular velocity of about 7 rad/s, (dB/dt of about 2 T/s). Inappropriate detection of ventricular fibrillation occurred at about 8 rad/s (dB/dt of about 3 T/s). These findings highlight the need for a specific risk assessment of workers with MR-conditional ICDs, which takes into account also effects that are generally not considered relevant for patients, such as the movement around the scanner bore.

  18. Focused tight dressing does not prevent cochlear implant magnet migration under 1.5 Tesla MRI.

    Science.gov (United States)

    Cuda, D; Murri, A; Succo, G

    2013-04-01

    We report a retrospective case of inner magnet migration, which occurred after 1.5 Tesla MRI scanning in an adult recipient of a bilateral cochlear implant (CI) despite a focused head dressing. The patient, bilaterally implanted with Nucleus 5 CIs (Cochlear LTD, Sydney, Australia), underwent a 1.5 Tesla cholangio-MRI scan for biliary duct pathology. In subsequent days, a focal skin alteration appeared over the left inner coil. Plain skull radiographs showed partial magnet migration on the left side. Surgical exploration confirmed magnet twisting; the magnet was effectively repositioned. Left CI performance was restored to pre-migration level. The wound healed without complications. Thus, focused dressing does not prevent magnet migration in CI recipients undergoing 1.5 Tesla MRI. All patients should be counselled on this potential complication. A minor surgical procedure is required to reposition the magnet. Nevertheless, timely diagnosis is necessary to prevent skin breakdown and subsequent device contamination. Plain skull radiograph is very effective in identifying magnet twisting; it should be performed systematically after MRI or minimally on all suspected cases.

  19. Correlation of histological findings with gadolinium enhanced MRI scans during healing of a PHEMA orbital implant in rabbits

    OpenAIRE

    Hicks, C.; Morris, I.; Vijayasekaran, S; Fallon, M.; McAllister, J.; Clayton, A.; Chirila, T.; Crawford, G; Constable, I

    1999-01-01

    BACKGROUND/AIMS—To investigate a poly(2-hydroxyethyl methacrylate) (PHEMA) orbital implant with a spongy anterior hemisphere and a smooth gel posterior hemisphere, by histology correlated with magnetic resonance images.
METHODS—Following enucleation, eight rabbits received PHEMA implants to which the muscles were directly sutured, and underwent gadolinium enhanced magnetic resonance imaging (MRI) from 3 to 52 weeks. After the rabbits were killed, the implants were removed, cut in a plane corr...

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

    Science.gov (United States)

    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.

  1. [Influence of implants on human body during MRI examinations: fundamental experiment using metal balls].

    Science.gov (United States)

    Muranaka, Hiroyuki; Nakamura, Osamu; Usui, Shuji; Ueda, Yoshitake; Morikawa, Kaoru

    2005-07-20

    It is increasingly the case that patients who have implants feel pain during high-field MRI examinations. A probable reason for the pain is the generation by irradiation of RF pulses and changing of the magnetic field gradient. As a fundamental study on the effect of implants on the human body under MRI procedures, temperature measurements were obtained from metal balls incorporated into gel-filled phantoms by using two kinds of measuring instruments, a copper-constantan thermocouple and a fluorescence fiber thermometer. At first we pursued a correlation between a copper-constantan thermocouple (absolute measurement) and fluoroptic thermometer and confirmed the precision and stability of the fluoroptic thermometer under MRI procedures. When a stainless steel ball with or without a loop antenna was used, only in the former case did the temperature rise during RF pulse irradiation. There was no significant difference between the magnetic field gradient ON and OFF. Furthermore, differences in metal (steel, aluminum, brass, stainless steel, copper) and size (5, 10, 20 mmPhi) were affected according to the increase of temperature. In conclusion, both RF pulse irradiation and a loop antenna are necessary for heat generation on the surface of metals.

  2. Passive and active middle ear implants

    Directory of Open Access Journals (Sweden)

    Beutner, Dirk

    2009-01-01

    Full Text Available Besides eradication of chronic middle ear disease, the reconstruction of the sound conduction apparatus is a major goal of modern ear microsurgery. The material of choice in cases of partial ossicular replacement prosthesis is the autogenous ossicle. In the event of more extensive destruction of the ossicular chain diverse alloplastic materials, e.g. metals, ceramics, plastics or composits are used for total reconstruction. Their specialised role in conducting sound energy within a half-open implant bed sets high demands on the biocompatibility as well as the acoustic-mechanic properties of the prosthesis. Recently, sophisticated titanium middle ear implants allowing individual adaptation to anatomical variations are widely used for this procedure. However, despite modern developments, hearing restoration with passive implants often faces its limitations due to tubal-middle-ear dysfunction. Here, implantable hearing aids, successfully used in cases of sensorineural hearing loss, offer a promising alternative. This article reviews the actual state of affairs of passive and active middle ear implants.

  3. MRI-Based Multiscale Model for Electromagnetic Analysis in the Human Head with Implanted DBS

    Directory of Open Access Journals (Sweden)

    Maria Ida Iacono

    2013-01-01

    Full Text Available Deep brain stimulation (DBS is an established procedure for the treatment of movement and affective disorders. Patients with DBS may benefit from magnetic resonance imaging (MRI to evaluate injuries or comorbidities. However, the MRI radio-frequency (RF energy may cause excessive tissue heating particularly near the electrode. This paper studies how the accuracy of numerical modeling of the RF field inside a DBS patient varies with spatial resolution and corresponding anatomical detail of the volume surrounding the electrodes. A multiscale model (MS was created by an atlas-based segmentation using a 1 mm3 head model (mRes refined in the basal ganglia by a 200 μm2 ex-vivo dataset. Four DBS electrodes targeting the left globus pallidus internus were modeled. Electromagnetic simulations at 128 MHz showed that the peak of the electric field of the MS doubled (18.7 kV/m versus 9.33 kV/m and shifted 6.4 mm compared to the mRes model. Additionally, the MS had a sixfold increase over the mRes model in peak-specific absorption rate (SAR of 43.9 kW/kg versus 7 kW/kg. The results suggest that submillimetric resolution and improved anatomical detail in the model may increase the accuracy of computed electric field and local SAR around the tip of the implant.

  4. MRI-Based Multiscale Model for Electromagnetic Analysis in the Human Head with Implanted DBS

    Science.gov (United States)

    Iacono, Maria Ida; Makris, Nikos; Mainardi, Luca; Angelone, Leonardo M.; Bonmassar, Giorgio

    2013-01-01

    Deep brain stimulation (DBS) is an established procedure for the treatment of movement and affective disorders. Patients with DBS may benefit from magnetic resonance imaging (MRI) to evaluate injuries or comorbidities. However, the MRI radio-frequency (RF) energy may cause excessive tissue heating particularly near the electrode. This paper studies how the accuracy of numerical modeling of the RF field inside a DBS patient varies with spatial resolution and corresponding anatomical detail of the volume surrounding the electrodes. A multiscale model (MS) was created by an atlas-based segmentation using a 1 mm3 head model (mRes) refined in the basal ganglia by a 200 μm2 ex-vivo dataset. Four DBS electrodes targeting the left globus pallidus internus were modeled. Electromagnetic simulations at 128 MHz showed that the peak of the electric field of the MS doubled (18.7 kV/m versus 9.33 kV/m) and shifted 6.4 mm compared to the mRes model. Additionally, the MS had a sixfold increase over the mRes model in peak-specific absorption rate (SAR of 43.9 kW/kg versus 7 kW/kg). The results suggest that submillimetric resolution and improved anatomical detail in the model may increase the accuracy of computed electric field and local SAR around the tip of the implant. PMID:23956789

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

    Energy Technology Data Exchange (ETDEWEB)

    Lim, T; Wang, J; Kudchadker, R; Stafford, R; Bathala, T; Pugh, T; Ibbott, G; Frank, S [UT MD Anderson Cancer Center, Houston, TX (United States)

    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

  6. Cochlear implant benefits in deafness rehabilitation: PET study of temporal voice Activations

    Energy Technology Data Exchange (ETDEWEB)

    Coez, A.; Zilbovicius, M. [CEA, Serv Hosp Frederic Joliot, INSERM, Res Unit Neuroimaging and Psychiat, U797, IFR49, F-91406 Orsay (France); Zilbovicius, M.; Syrota, A.; Samson, Y. [CEA, DSV, DRM, Serv Hosp Frederic Joliot, F-91406 Orsay (France); Bizaguet, E. [Lab Correct Audit, Paris (France); Coez, A. [Univ Paris Sud 11, Paris (France); Ferrary, E.; Bouccara, D.; Mosnier, I.; Sterkers, O. [INSERM, Unit M 867, Paris (France); Ambert-Dahan, E. [Hop Beaujon, Serv ORL Chirurg Cervicofaciale, AP-HP, Clichy (France); Ferrary, E.; Bouccara, D.; Mosnier, I.; Sterkers, O. [Inst Fed Rech Claude Bernard Physiol et Pathol, IFR02, Paris (France); Samson, Y. [Hop La Pitie Salpetriere, Serv Urgences Cerebro-vasc, AP-HP, Paris (France); Samson, Y. [Univ Paris 06, Paris (France); Sterkers, O. [Univ Denis Diderot Paris 7, Paris (France)

    2008-07-01

    Cochlear implants may improve the medical and social prognosis of profound deafness. Nevertheless, some patients have experienced poor results without any clear explanations. One correlate may be an alteration in cortical voice processing. To test this hypothesis, we studied the activation of human temporal voice areas (TVA) using a well-standardized PET paradigm adapted from previous functional MRI (fMRI) studies. Methods: A PET H{sub 2}{sup 15}O activation study was performed on 3 groups of adult volunteers: normal-hearing control subjects (n 6) and cochlear-implanted post-lingually deaf patients with {>=}2 y of cochlear implant experience, with intelligibility scores in the 'Lafon monosyllabic task' {>=}80% (Good group; n 6) or {<=}20% (Poor group; n 6). Relative cerebral blood flow was measured in 3 conditions: rest, passive listening to human voice, and non-voice stimuli. Results: Compared with silence, the activations induced by non-voice stimuli were bilaterally located in the superior temporal regions in all groups. However these activations were significantly and similarly reduced in both cochlear implant groups, whereas control subjects showed supplementary activations. Compared with non-voice, the voice stimuli induced bilateral activation of the TVA along the superior temporal sulcus (STS) in both the control and the Good groups. In contrast, these activations were not detected in the Poor group, which showed only left unilateral middle STS activation. Conclusion: These results suggest that PET is an adequate method to explore cochlear implant benefits and that this benefit could be linked to the activation of the TVA. (authors)

  7. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... Examples include but are not limited to: artificial heart valves implanted drug infusion ports artificial limbs or ... imaging based on the electrical activity of the heart, such as electrocardiography (EKG). MRI generally is not ...

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

    Science.gov (United States)

    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

  9. Halofuginone Inhibits Angiogenesis and Growth in Implanted Metastatic Rat Brain Tumor Model-an MRI Study

    Directory of Open Access Journals (Sweden)

    Rinat Abramovitch

    2004-09-01

    Full Text Available Tumor growth and metastasis depend on angiogenesis; therefore, efforts are made to develop specific angiogenic inhibitors. Halofuginone (HF is a potent inhibitor of collagen type α1(I. In solid tumor models, HF has a potent antitumor and antiangiogenic effect in vivo, but its effect on brain tumors has not yet been evaluated. By employing magnetic resonance imaging (MRI, we monitored the effect of HF on tumor progression and vascularization by utilizing an implanted malignant fibrous histiocytoma metastatic rat brain tumor model. Here we demonstrate that treatment with HF effectively and dose-dependently reduced tumor growth and angiogenesis. On day 13, HF-treated tumors were fivefold smaller than control (P < .001. Treatment with HF significantly prolonged survival of treated animals (142%; P = .001. In HF-treated rats, tumor vascularization was inhibited by 30% on day 13 and by 37% on day 19 (P < .05. Additionally, HF treatment inhibited vessel maturation (P = .03. Finally, in HF-treated rats, we noticed the appearance of a few clusters of satellite tumors, which were distinct from the primary tumor and usually contained vessel cores. This phenomenon was relatively moderate when compared to previous reports of other antiangiogenic agents used to treat brain tumors. We therefore conclude that HF is effective for treatment of metastatic brain tumors.

  10. Spatial resolution and maximum compensation factor of two-dimensional selective excitation pulses for MRI of objects containing conductive implants

    Directory of Open Access Journals (Sweden)

    Taeseong Woo

    2017-05-01

    Full Text Available A quantitative diagnosis using magnetic resonance imaging (MRI can be disturbed by radiofrequency (RF field inhomogeneity induced by the conductive implants. This inhomogeneity causes a local decrease of the signal intensity around the conductor, resulting in a deterioration of the accurate quantification. In a previous study, we developed an MRI imaging method using a two-dimensional selective excitation pulse (2D pulse to mitigate signal inhomogeneity induced by metallic implants. In this paper, the effect of 2D pulse was evaluated quantitatively by numerical simulation and MRI experiments. We introduced two factors for evaluation, spatial resolution and maximum compensation factor. Numerical simulations were performed with two groups. One group was composed of four models with different signal loss width, to evaluate the spatial resolution of the 2D pulse. The other group is also composed of four models with different amounts of signal loss for evaluating maximum compensation factor. In MRI experiments, we prepared phantoms containing conductors, which have different electrical conductivities related with the amounts of signal intensity decrease. The recovery of signal intensity was observed by 2D pulses, in both numerical simulations and experiments.

  11. MRI scanning in patients implanted with a round window or stapes coupled floating mass transducer of the Vibrant Soundbridge.

    Science.gov (United States)

    Renninger, Daniel; Ernst, Arne; Todt, Ingo

    2016-01-01

    Conclusion MRI examinations in patients with an alternatively coupled VSB can lead to unpleasant side-effects. However, the residual hearing was not impaired, whereas the hearing performance with the VSB was decreased in one patient which could be fixed by a surgical revision. Different experiences for the VSB 503 can be expected. Objective To investigate the in vivo effects of MRI scanning on the Vibrant Soundbridge system (VSB) with an alternatively coupled Floating Mass Transducer (FMT). Method Sixty-five VSB (502) implantees were included in this study. Of them, 42 questionnaires could be evaluated with the patients' statements about their medical, otological, and general condition before, during, and after an MRI scan which was indicated for different medical reasons, despite the previous implantation of an alternatively coupled Vibrant Soundbridge System. Results In four patients (9.5%), five MRI examinations were performed. These were done for different indications (e.g. knee and shoulder joint diagnostics). During the scanning, noise and subjectively perceived distortion of the implant were described. A deterioration of the hearing gain with the VSB in place was found in one patient. A decrease of the hearing threshold was not observed.

  12. [Botulinum toxin to treat sweat caused sequelae in patients with hearing aids, active middle ear implants and cochlear implants].

    Science.gov (United States)

    Laskawi, R; Winterhoff, J; Blum, J; Matthias, C

    2012-11-01

    The production of sweat in the temporal skin region may be a serious problem for patients with hearing aids, active middle ear implants or cochlear implants. We report on two patients suffering from a loss of function of their hearing aid and a reduction of the "wear comfort" of an active middle ear implant. The patients underwent intracutaneous botulinum toxin (BTX) treatment of the temporal skin region. In both patients a distinct improvement of their complaints occurred, enabling them to use their hearing aids and active middle ear implants continuously. BTX injections are suited to improve sweat-caused complaints in patients with hearing aids, active middle ear implants and cochlear implants.

  13. An Introduction to Cochlear Implant Technology, Activation, and Programming.

    Science.gov (United States)

    Moore, Jan A.; Teagle, Holly F. B.

    2002-01-01

    This article provides information about the hardware components and speech-processing strategies of cochlear implant systems. The use of assistive listening devices with cochlear implants is also discussed. A brief description of surgical procedures and the initial activation of the device are also presented, along with programming considerations.…

  14. Sporting Activity Is Reduced 11 Years After First-Generation Autologous Chondrocyte Implantation in the Knee Joint

    DEFF Research Database (Denmark)

    Erdle, Benjamin; Herrmann, Simon; Porichis, Stella

    2017-01-01

    of sporting activity correlated significantly with clinical long-term outcomes. MRI analysis with a mean repair tissue T2 relaxation time of 35.2 milliseconds and mean MOCART score of 44.9 showed no conclusive significant correlation to sporting activity. Level of performance was the only sporting activity......BACKGROUND: Little is known about long-term sporting activity after periosteal autologous chondrocyte implantation (ACI-P) and its correlation to clinical, morphological, and ultrastructural cartilage characteristics on magnetic resonance imaging (MRI). PURPOSE: To evaluate long-term sporting...... activity after ACI-P and to correlate with clinical and MRI findings. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Patients who underwent ACI-P for isolated cartilage defects of the knee joint between 1997 and 2001 were analyzed for sporting ability for 3 different time points: lifetime until...

  15. Defining active sacroiliitis on MRI for classification of axial spondyloarthritis: update by the ASAS MRI working group

    DEFF Research Database (Denmark)

    Lambert, Robert G W; Bakker, Pauline A C; van der Heijde, Désirée

    2016-01-01

    . CONCLUSION: The definition of a positive MRI for classification of axial SpA should continue to primarily depend on the imaging features of 'active sacroiliitis' until more data are available regarding MRI features of structural damage in the sacroiliac joint and MRI features in the spine and their utility......OBJECTIVES: To review and update the existing definition of a positive MRI for classification of axial spondyloarthritis (SpA). METHODS: The Assessment in SpondyloArthritis International Society (ASAS) MRI working group conducted a consensus exercise to review the definition of a positive MRI...... for inclusion in the ASAS classification criteria of axial SpA. Existing definitions and new data relevant to the MRI diagnosis and classification of sacroiliitis and spondylitis in axial SpA, published since the ASAS definition first appeared in print in 2009, were reviewed and discussed. The precise wording...

  16. Investigation of fMRI activation in the internal capsule

    Directory of Open Access Journals (Sweden)

    Brewer Kimberley D

    2011-06-01

    Full Text Available Abstract Background Functional magnetic resonance imaging (fMRI in white matter has long been considered controversial. Recently, this viewpoint has been challenged by an emerging body of evidence demonstrating white matter activation in the corpus callosum. The current study aimed to determine whether white matter activation could be detected outside of the corpus callosum, in the internal capsule. Data were acquired from a 4 T MRI using a specialized asymmetric spin echo spiral sequence. A motor task was selected to elicit activation in the posterior limb of the internal capsule. Results White matter fMRI activation was examined at the individual and group levels. Analyses revealed that activation was present in the posterior limb of the internal capsule in 80% of participants. These results provide further support for white matter fMRI activation. Conclusions The ability to visualize functionally active tracts has strong implications for the basic scientific study of connectivity and the clinical assessment of white matter disease.

  17. MRI

    Science.gov (United States)

    MRI does not use ionizing radiation. No side effects from the magnetic fields and radio waves have been reported. The most common type of contrast (dye) used is gadolinium. It is very safe. Allergic reactions rarely ...

  18. Energetics of neuronal signaling and fMRI activity.

    Science.gov (United States)

    Maandag, Natasja J G; Coman, Daniel; Sanganahalli, Basavaraju G; Herman, Peter; Smith, Arien J; Blumenfeld, Hal; Shulman, Robert G; Hyder, Fahmeed

    2007-12-18

    Energetics of resting and evoked fMRI signals were related to localized ensemble firing rates (nu) measured by electrophysiology in rats. Two different unstimulated, or baseline, states were established by anesthesia. Halothane and alpha-chloralose established baseline states of high and low energy, respectively, in which forepaw stimulation excited the contralateral primary somatosensory cortex (S1). With alpha-chloralose, forepaw stimulation induced strong and reproducible fMRI activations in the contralateral S1, where the ensemble firing was dominated by slow signaling neurons (SSN; nu range of 1-13 Hz). Under halothane, weaker and less reproducible fMRI activations were observed in the contralateral S1 and elsewhere in the cortex, but ensemble activity in S1 was dominated by rapid signaling neurons (RSN; nu range of 13-40 Hz). For both baseline states, the RSN activity (i.e., higher frequencies, including the gamma band) did not vary upon stimulation, whereas the SSN activity (i.e., alpha band and lower frequencies) did change. In the high energy baseline state, a large majority of total oxidative energy [cerebral metabolic rate of oxygen consumption (CMR(O2))] was devoted to RSN activity, whereas in the low energy baseline state, it was roughly divided between SSN and RSN activities. We hypothesize that in the high energy baseline state, the evoked changes in fMRI activation in areas beyond S1 are supported by rich intracortical interactions represented by RSN. We discuss implications for interpreting fMRI data where stimulus-specific DeltaCMR(O2) is generally small compared with baseline CMR(O2).

  19. Magnet discolation - An increasing and serious complication following MRI in patients with chochlear implants; Magnetdiskolation - eine zunehmende und folgenreiche Komplikation nach MRT bei Patienten mit Cochlea Implantat

    Energy Technology Data Exchange (ETDEWEB)

    Hassepass, F.; Staubenau, V.; Arndt, S.; Beck, R.; Grauvogel, T.; Aschendorff, A. [Univ. Medical Center Freiburg (Germany). Dept. of Otorhinolaryngology-Head and Neck Surgery; Bulla, S. [Univ. Medical Center Freiburg (Germany). Dept. of Diagnostic Radiology

    2014-07-15

    Cochlear implantation (CI) represents the gold standard in the treatment of children born deaf and postlingually deafened adults. Initial magnetic resonance imaging (MRI) was contraindicated in CI users. Meanwhile, there are specific recommendations concerning MRI compatibility depending on the type of CI system and the device manufacturer. Some CI systems are even approved for MRI with the internal magnet left in place. The aim of this study was to analyze all magnet revision surgeries in CI patients at one CI center and the relationship to MRI scans over time. Between 2000 and 2013, a total of 2027 CIs were implanted. The number of magnet dislocation (MD) surgeries and their causes was assessed retrospectively. In total 12 cases of MD resulting from an MRI scan (0.59 %) were observed, accounting for 52.2 % of all magnetic revision surgeries. As per the labeling, it was considered safe to leave the internal magnet in place during MRI while following specific manufacturer recommendations: MRI intensity of 1.5 Tesla (T) and compression head bandage during examination. A compression head bandage in a 1.5 T MRI unit does not safely prevent MD and the related serious complications in CI recipients. We recommend a Stenvers view radiograph after MRI with the internal magnet in place for early identification of MD, at least in the case of pain during or after MRI examination. MRI in CI patients should be indicated with restraint and patients should be explicitly informed about the possible risks. Recommendations regarding MRI compatibility and the handling of CI patients issued with MRI for the most common CI systems are summarized.

  20. On the estimation of the worst-case implant-induced RF-heating in multi-channel MRI

    Science.gov (United States)

    Córcoles, Juan; Zastrow, Earl; Kuster, Niels

    2017-06-01

    The increasing use of multiple radiofrequency (RF) transmit channels in magnetic resonance imaging (MRI) systems makes it necessary to rigorously assess the risk of RF-induced heating. This risk is especially aggravated with inclusions of medical implants within the body. The worst-case RF-heating scenario is achieved when the local tissue deposition in the at-risk region (generally in the vicinity of the implant electrodes) reaches its maximum value while MRI exposure is compliant with predefined general specific absorption rate (SAR) limits or power requirements. This work first reviews the common approach to estimate the worst-case RF-induced heating in multi-channel MRI environment, based on the maximization of the ratio of two Hermitian forms by solving a generalized eigenvalue problem. It is then shown that the common approach is not rigorous and may lead to an underestimation of the worst-case RF-heating scenario when there is a large number of RF transmit channels and there exist multiple SAR or power constraints to be satisfied. Finally, this work derives a rigorous SAR-based formulation to estimate a preferable worst-case scenario, which is solved by casting a semidefinite programming relaxation of this original non-convex problem, whose solution closely approximates the true worst-case including all SAR constraints. Numerical results for 2, 4, 8, 16, and 32 RF channels in a 3T-MRI volume coil for a patient with a deep-brain stimulator under a head imaging exposure are provided as illustrative examples.

  1. Brain activation in response to visceral stimulation in rats with amygdala implants of corticosterone: an FMRI study.

    Directory of Open Access Journals (Sweden)

    Anthony C Johnson

    Full Text Available BACKGROUND: Although visceral pain of gastrointestinal (GI origin is the major complaint in patients with irritable bowel syndrome (IBS it remains poorly understood. Brain imaging studies suggest a defect in brain-gut communication in IBS with a greater activation of central arousal circuits including the amygdala. Previously, we found that stereotaxic implantation of corticosterone (CORT onto the amygdala in rats induced anxiety and colonic hypersensitivity. In the present study we used functional magnetic resonance imaging (fMRI to identify specific brain sites activated in a rat model characterized by anxiety and colonic hypersensitivity. METHODOLOGY/PRINCIPAL FINDINGS: Anesthetized male rats received micropellets (30 microg each of either CORT or cholesterol (CHOL, to serve as a control, implanted stereotaxically on the dorsal margin of each amygdala. Seven days later, rats were anesthetized and placed in the fMRI magnet (7T. A series of isobaric colorectal balloon distensions (CRD - 90s 'off', 30s 'on', 8 replicates at two pressures (40 and 60 mmHg were performed in a standard block-design. Cross correlation statistical analysis was used to determine significant differences between distended and non-distended states in CORT and CHOL-treated animals. Analysis of the imaging data demonstrated greater overall brain activation in response to CRD in rats with CORT implants compared to CHOL controls. Additionally, CORT implants produced significant positive bilateral increases in MRI signal in response to CRD in specific nuclei known as integration sites important in anxiety and pain perception. CONCLUSIONS AND SIGNIFICANCE: These data indicate that chronic exposure of the amygdala to elevated levels of CORT enhances overall brain activation in response to CRD, and identified other specific brain regions activated in response to mechanical distension of the colon. These results demonstrate the feasibility of performing fMRI imaging in a rodent

  2. Imaging brain neuronal activity using functionalized magnetonanoparticles and MRI.

    Science.gov (United States)

    Akhtari, Massoud; Bragin, Anatol; Moats, Rex; Frew, Andrew; Mandelkern, Mark

    2012-10-01

    This study explored the use of non-radioactive 2-deoxy glucose (2DG)-labeled magnetonanoparticles (MNP) and magnetic resonance imaging (MRI) to detect functional activity during rest, peripheral stimulation, and epileptic seizures, in animal models. Non-radioactive 2DG was covalently attached to magnetonanoparticles composed of iron oxide and dextran and intravenous (tail) injections were performed. 2DG-MNP was injected in resting and stimulated naïve rodents and the subsequent MRI was compared to published (14)C-2DG autoradiography data. Reproducibility and statistical significance was established in one studied model. Negative contrast enhancement (NCE) in acute seizures and chronic models of epilepsy were investigated. MRI NCE due to 2DG-MNP particles was compared to that of plain (unconjugated) MNP in one animal. NCE due to 2DG-MNP particles at 3 T, which is approved for human use, was also investigated. Histology showed presence of MNP (following intravenous injection) in the brain tissues of resting naïve animal. 2DG-MNP intraparenchymal uptake was visible on MRI and histology. The locations of NCE agreed with published results of 2DG autoradiography in resting and stimulated animals and epileptic rats. Localization of epileptogenicity was confirmed by subsequent depth-electrode EEG (iEEG). Non-radioactive 2DG-MNP can cross the blood-brain barrier (BBB) and may accurately localize areas of increased activity. Although, this proof-of-principle study involves only a limited number of animals, and much more research and quantification are necessary to demonstrate that 2DG-MNP, or MNPs conjugated with other ligands, could eventually be used to image localized cerebral function with MRI in humans, this MNP-MRI approach is potentially applicable to the use of many bioactive molecules as ligands for imaging normal and abnormal localized cerebral functions.

  3. Cochlear Implants

    Science.gov (United States)

    ... imaging (MRI) scans, to evaluate your inner ear anatomy. Cochlear implant surgery Cochlear implant surgery is usually performed as an outpatient procedure under general anesthesia. An incision is made behind the ear ...

  4. Prevention of Cutaneous Tissue Contracture During Removal of Craniofacial Implant Superstructures for CT and MRI Studies

    Directory of Open Access Journals (Sweden)

    Maureen Sullivan

    2010-04-01

    Full Text Available Objectives: Head and neck cancer patients who have lost facial parts following surgical intervention frequently require craniofacial implant retained facial prostheses for restoration. Many craniofacial implant patients require computed tomography and magnetic resonance imaging scans as part of their long-term follow-up care. Consequently removal of implant superstructures and peri-abutment tissue management is required for those studies. The purpose of the present paper was to describe a method for eliminating cranial imaging artifacts in patients with craniofacial implants.Material and Methods: Three patients wearing extraoral implant retained facial prostheses needing either computed tomography or magnetic resonance imaging studies were discussed. Peri-implant soft tissues contracture after removal of percutaneous craniofacial implant abutments during computed tomography and magnetic resonance imaging studies was prevented using a method proposed by authors. The procedure involves temporary removal of the supra-implant components prior to imaging and filling of the tissue openings with polyvinyl siloxane dental impression material.Results: Immediately after filling of the tissue openings with polyvinyl siloxane dental impression material patients were sent for the imaging studies, and were asked to return for removal of the silicone plugs and reconnection of all superstructure hardware after imaging procedures were complete. The silicone plugs were easily removed with a dental explorer. The percutaneous abutments were immediately replaced and screwed into the implants which were at the bone level.Conclusions: Presented herein method eliminates the source of artifacts and prevents contracture of percutaneous tissues upon removal of the implant abutments during imaging.

  5. MRI of the heart following implantation of a left ventricular apico-aortic conduit; Kernspintomografie zur umfassenden Untersuchung des Herzens nach Implantation von linksventrikulaeren apikoaortalen Conduits

    Energy Technology Data Exchange (ETDEWEB)

    Ruhl, K.M.; Katoh, M.; Guenther, R.W.; Krombach, G.A. [Technische Hochschule Aachen (Germany). Klinik fuer Radiologische Diagnostik; Langebartels, G.; Autschbach, R. [Technische Hochschule Aachen (Germany). Klinik fuer Thorax-, Herz- und Gefaesschirurgie

    2007-06-15

    Purpose: To investigate the potential of ECG-triggered MRI for the evaluation of postoperative anatomy and function of the heart and conduit following implantation of a left-ventricular apico-aortic conduit. Materials and Methods: 5 patients (2 female, 3 male, mean age 72.5 years) were examined using a 1.5 Tesla whole-body MRI (Gyroscan Intera, Philips Medical Systems, Best, The Netherlands) following apico-aortic conduit surgery due to severe aortic valve stenosis. The reason for performing conduit implantation instead of aortic valve replacement was the risk of injuring a bypass graft from prior coronary artery bypass surgery. Cine steady-state-free-precession (SSFP) sequences were used to assess ventricular function, navigator-gated 3D-SSFP and breath-hold, time-resolved contrast-enhanced MR angiography was used to display the postoperative anatomy, and 2D-gradient echo sequences with an inversion pulse to suppress the signal of the healthy myocardium were used to evaluate potential myocardial scarring. Flow sensitive gradient echo sequences were performed to determine the blood flow in the conduit. Results: In all patients the apico-aortic conduit proved to be open with a maximum flow velocity of 126 (+ 43) cm/s. The postoperative anatomy was able to be evaluated in all patients and perioperative myocardial infarction was able to be ruled out. The mean ejection fraction of the left ventricle was 44.2 + 6.2 % with a mean volume of 80 + 20.6 ml per heart beat. (orig.)

  6. Optimization of scan time in MRI for total hip prostheses. SEMAC tailoring for prosthetic implants containing different types of metals

    Energy Technology Data Exchange (ETDEWEB)

    Deligianni, X. [University of Basel Hospital, Basel (Switzerland). Div. of Radiological Physics; Merian Iselin Klinik, Basel (Switzerland). Inst. of Radiology; Bieri, O. [University of Basel Hospital, Basel (Switzerland). Div. of Radiological Physics; Elke, R. [Orthomerian, Basel (Switzerland); Wischer, T.; Egelhof, T. [Merian Iselin Klinik, Basel (Switzerland). Inst. of Radiology

    2015-12-15

    Magnetic resonance imaging (MRI) of soft tissues after total hip arthroplasty is of clinical interest for the diagnosis of various pathologies that are usually invisible with other imaging modalities. As a result, considerable effort has been put into the development of metal artifact reduction MRI strategies, such as slice encoding for metal artifact correction (SEMAC). Generally, the degree of metal artifact reduction with SEMAC directly relates to the overall time spent for acquisition, but there is no specific consensus about the most efficient sequence setup depending on the implant material. The aim of this article is to suggest material-tailored SEMAC protocol settings. Five of the most common total hip prostheses (1. Revision prosthesis (S-Rom), 2. Titanium alloy, 3. Mueller type (CoNiCRMo alloy), 4. Old Charnley prosthesis (Exeter/Stryker), 5. MS-30 stem (stainless-steel)) were scanned on a 1.5 T MRI clinical scanner with a SEMAC sequence with a range of artifact-resolving slice encoding steps (SES: 2 - 23) along the slice direction (yielding a total variable scan time ranging from 1 to 10 min). The reduction of the artifact volume in comparison with maximal artifact suppression was evaluated both quantitatively and qualitatively in order to establish a recommended number of steps for each case. The number of SES that reduced the artifact volume below approximately 300 mm{sup 3} ranged from 3 to 13, depending on the material. Our results showed that although 3 SES steps can be sufficient for artifact reduction for titanium prostheses, at least 11 SES should be used for prostheses made of materials such as certain alloys of stainless steel. Tailoring SES to the implant material and to the desired degree of metal artifact reduction represents a simple tool for workflow optimization of SEMAC imaging near total hip arthroplasty in a clinical setting.

  7. Active MRI tracking for robotic assisted FUS

    Science.gov (United States)

    Xiao, Xu; Huang, Zhihong; Melzer, Andreas

    2017-03-01

    MR guided FUS is a noninvasive method producing thermal necrosis at the position of tumors with high accuracy and temperature control. Because the typical size of the ultrasound focus is smaller than the area of interested treatment tissues, focus repositioning become necessary to achieve multiple sonications to cover the whole targeted area. Using MR compatible mechanical actuators could help the ultrasound beam to reach a wider treatment range than using electrical beam steering technique and more flexibility in position the transducer. An active MR tracking technique was combined into the MRgFUS system to help locating the position of the mechanical actuator and the FUS transducer. For this study, a precise agar reference model was designed and fabricated to test the performance of the active tracking technique when it was used on the MR-compatible robotics InnoMotion™ (IBSMM, Engineering spol. s r.o. / Ltd, Czech Republic). The precision, tracking range and positioning speed of the combined robotic FUS system were evaluated in this study. Compared to the existing MR guided HIFU systems, the combined robotic system with active tracking techniques provides a potential that allows the FUS treatment to operate in a larger spatial range and with a faster speed, which is one of the main challenges for organ motion tracking.

  8. MRI and MRS in patients with silicon implants of the breast; MRT und MRS nach Silikonaufbau der weiblichen Brust

    Energy Technology Data Exchange (ETDEWEB)

    Pfleiderer, B.; Heindel, W. [Muenster Univ. (Germany). Radiologische Klinik und Poliklinik

    2001-07-01

    This paper reviews the evaluation of the breast of women by MR-techniques after implantation with silicon gel protheses. The main topics are the diagnosis of implant defects such as extensive ''gel bleed'' and intra- and extracapsular ruptures. Moreover, the MR-detection of siliconomas (encapsulated silicone) and differentiation from malignomas as well as MR-features of chronic foreign body reactions are presented. ''Gel bleed'' is difficult to diagnose unambiguously by MRI alone. The ''linguini'' sign is the only reliable mans to diagnose intracapsular ruptures. The presence of silicone outside the implant capsule indicates extracapsular rupture. The MR-spectroscopic detection of silicone in the liver suggests after short implantation times and a normal MR scan the diagnosis ''gel bleed'', and after longer implantation times of more than 10 years and missing ''linguini'' sign the diagnosis of ruptures due to a dissolved shell of the implant. MRI, in comparison to other imaging modalities, has the highest specificity and sensitivity in the diagnosis of implant defects. Due to its high costs, however, MR is not suitable as a screening tool and should only be used in cases of sonographic suspected rupture or after radical mastectomy. In these cases MRI is the method of choice. (orig.) [German] In dieser Uebersicht wird die Evaluation der weiblichen Brust nach Aufbau mit Silikonmammaprothesen mittels MR-Techniken vorgestellt. Ein Schwerpunkt liegt dabei auf der Defektdiagnostik, d.h. dem Nachweis des so genannten ''Gelblutens'', der intra- und der extrakapsulaeren Ruptur. Daneben wird auf die MR-Detektion von Silikonomen (abgekapseltes Silikon) und deren Abgrenzung von einem Malignom eingegangen und das typische MR-Erscheinungsbild von chronischer Fremdkoerperreaktion vorgestellt. ''Gelbluten'' ist mittels MR-Bildgebung (MRT

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

    Directory of Open Access Journals (Sweden)

    Joshua Kahan

    Full Text Available 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.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.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.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 to be recruited to future fMRI

  10. MRI Brain Activation During Instruction of Dyslexic Children

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2003-08-01

    Full Text Available Ten children with dyslexia and 11 normal readers performed tasks of phoneme mapping (assigning sounds to letters and morpheme mapping (relating suffixed words to their roots during fMRI scanning, before and after 28 hours of comprehensive reading instruction, in a study of the effects of reading instruction on brain activation in children with dyslexia at University of Washington, Seattle, WA.

  11. Ventricular Assist Device implant (AB 5000 prototype cannula: In vitro assessment of MRI issues at 3-Tesla

    Directory of Open Access Journals (Sweden)

    Valencerina Samuel

    2008-05-01

    Full Text Available Abstract Purpose To evaluate MRI issues at 3-Tesla for a ventricular assist device (VAD. Methods The AB5000 Ventricle with a prototype Nitinol wire-reinforced In-Flow Cannula and Out-Flow Cannula attached (Abiomed, Inc., Danvers, MA was evaluated for magnetic field interactions, heating, and artifacts at 3-Tesla. MRI-related heating was assessed with the device in a gelled-saline-filled, head/torso phantom using a transmit/received RF body coil while performing MRI at a whole body averaged SAR of 3-W/kg for 15-min. Artifacts were assessed for the main metallic component of this VAD (atrial cannula using T1-weighted, spin echo and gradient echo pulse sequences. Results The AB5000 Ventricle with the prototype In-Flow Cannula and Out-Flow Cannula attached showed relatively minor magnetic field interactions that will not cause movement in situ. Heating was not excessive (highest temperature change, +0.8°C. Artifacts may create issues for diagnostic imaging if the area of interest is in the same area or close to the implanted metallic component of this VAD (i.e., the venous cannula. Conclusion The results of this investigation demonstrated that it would be acceptable for a patient with this VAD (AB5000 Ventricle with a prototype Nitinol wire-reinforced In-Flow Cannula and Out-Flow Cannula attached to undergo MRI at 3-Tesla or less. Notably, it is likely that the operation console for this device requires positioning a suitable distance (beyond the 100 Gauss line or in the MR control room from the 3-Tesla MR system to ensure proper function of the VAD.

  12. Treatment of hepatocellular carcinoma adjacent to large blood vessels using 1.5T MRI-guided percutaneous radiofrequency ablation combined with iodine-125 radioactive seed implantation

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Zheng-Yu, E-mail: linsinlan@yahoo.com.cn [The Department of Radiology, First Affiliated Hospital of Fujian Medical University, 20 Chazhong Road, Fuzhou 350005 (China); Chen, Jin, E-mail: snow8968851@163.com [The Department of Radiology, First Affiliated Hospital of Fujian Medical University, 20 Chazhong Road, Fuzhou 350005 (China); Deng, Xiu-Fen, E-mail: dxf197286@yahoo.com.cn [The Department of Radiology, First Affiliated Hospital of Fujian Medical University, 20 Chazhong Road, Fuzhou 350005 (China)

    2012-11-15

    Objective: The objective is to study the technology associated with and feasibility of the treatment of hepatocellular carcinoma (HCC) adjacent to large blood vessels using 1.5T MRI-guided radiofrequency ablation combined with iodine-125 (I-125) radioactive seed implantation. Methods: Sixteen patients with a total of 24 HCC lesions (average maximum diameter: 2.35 {+-} 1.03 cm) were pathologically confirmed by biopsy or clinically diagnosed received 1.5T MRI-guided percutaneous radiofrequency ablation (RFA) treatment. Each patient had one lesion adjacent to large blood vessels ({>=}3 mm); after the ablation, I-125 radioactive seeds were implanted in the portions of the lesions that were adjacent to the blood vessels. Results: All the ablations and I-125 radioactive seed implantations were successful; a total of 118 seeds were implanted. The ablated lesions exhibited hypointense signals on the T2WI sequence with a thin rim of hyperintense signals; they also exhibited significant hyperintense signals on the T1WI sequence with clear boundaries. The average follow-up period was 11.1 {+-} 6.2 months. There were 23 complete responses and one partial response in the 24 lesions. The alpha-fetoprotein (AFP) levels of the patients significantly decreased. Conclusion: The 1.5T MRI-guided RFA combined with I-125 radioactive seed implantation for the treatment of HCC adjacent to large blood vessels is an effective technology.

  13. The Role of MRI in Prostate Cancer Active Surveillance

    Directory of Open Access Journals (Sweden)

    Linda M. Johnson

    2014-01-01

    Full Text Available Prostate cancer is the most common cancer diagnosis in American men, excluding skin cancer. The clinical behavior of prostate cancer varies from low-grade, slow growing tumors to high-grade aggressive tumors that may ultimately progress to metastases and cause death. Given the high incidence of men diagnosed with prostate cancer, conservative treatment strategies such as active surveillance are critical in the management of prostate cancer to reduce therapeutic complications of radiation therapy or radical prostatectomy. In this review, we will review the role of multiparametric MRI in the selection and follow-up of patients on active surveillance.

  14. Cortical language activation in aphasia:a functional MRI study

    Institute of Scientific and Technical Information of China (English)

    徐晓俊; 张敏鸣; 商德胜; 汪启东; 罗本燕; 翁旭初

    2004-01-01

    Background Functional neuroimaging has been used in neurolinguistic research on normal subjects and on patients with brain damage. This study was designed to investigate the differences of the neural basis underlying language processing between normal subjects and aphasics.Methods Functional magnetic resonance imaging (fMRI) was used to map the language network in 6 normal subjects and 3 patients with aphasia who were in the stage of recovery from acute stroke. The participants performed a word generation task during multi-slice functional scanning for the measurement of signal change associated with regional neural activity induced by the task. Results In normal subjects, a distributed language network was activated. Activations were present in the frontal, temporal, parietal and occipital regions. In the patient group, however, no activation was detected in the left inferior frontal gyrus whether the patient had a lesion in the left frontal lobe or not. Two patients showed activations in some right hemisphere regions where no activation appeared in normal subjects. Conclusions fMRI with word generation task is feasible for evaluating language function in aphasic patients. Remote effect of focal lesion and functional redistribution or reorganisation can be found in aphasic patients.

  15. Anomalous activation of shallow B+ implants in Ge

    DEFF Research Database (Denmark)

    Yates, B.R.; Darby, B.L.; Rudawski, N.G.;

    2011-01-01

    The electrical activation of B+ implantation at 2 keV to doses of 5.0×1013-5.0×1015 cm-2 in crystalline and pre-amorphized Ge following annealing at 400 °C for 1.0 h was studied using micro Hall effect measurements. Preamorphization improved activation for all samples with the samples implanted...... to a dose of 5.0×1015 cm-2 displaying an estimated maximum active B concentration of 4.0×1020 cm-3 as compared to 2.0×1020 cm-3 for the crystalline sample. However, incomplete activation was observed for all samples across the investigated dose range. For the sample implanted to a dose of 5.0×1013 cm -2......, activation values were 7% and 30%, for c-Ge and PA-Ge, respectively. The results suggest the presence of an anomalous clustering phenomenon of shallow B+ implants in Ge. © 2011 Elsevier B.V. All rights reserved....

  16. Defining active sacroiliitis on MRI for classification of axial spondyloarthritis: update by the ASAS MRI working group.

    Science.gov (United States)

    Lambert, Robert G W; Bakker, Pauline A C; van der Heijde, Désirée; Weber, Ulrich; Rudwaleit, Martin; Hermann, K G; Sieper, Joachim; Baraliakos, Xenofon; Bennett, Alex; Braun, Jürgen; Burgos-Vargas, Rubén; Dougados, Maxime; Pedersen, Susanne Juhl; Jurik, Anne Grethe; Maksymowych, Walter P; Marzo-Ortega, Helena; Østergaard, Mikkel; Poddubnyy, Denis; Reijnierse, Monique; van den Bosch, Filip; van der Horst-Bruinsma, Irene; Landewé, Robert

    2016-11-01

    To review and update the existing definition of a positive MRI for classification of axial spondyloarthritis (SpA). The Assessment in SpondyloArthritis International Society (ASAS) MRI working group conducted a consensus exercise to review the definition of a positive MRI for inclusion in the ASAS classification criteria of axial SpA. Existing definitions and new data relevant to the MRI diagnosis and classification of sacroiliitis and spondylitis in axial SpA, published since the ASAS definition first appeared in print in 2009, were reviewed and discussed. The precise wording of the existing definition was examined in detail and the data and a draft proposal were presented to and voted on by the ASAS membership. The clear presence of bone marrow oedema on MRI in subchondral bone is still considered to be the defining observation that determines the presence of active sacroiliitis. Structural damage lesions seen on MRI may contribute to a decision by the observer that inflammatory lesions are genuinely due to SpA but are not required to meet the definition. The existing definition was clarified adding guidelines and images to assist in the application of the definition. The definition of a positive MRI for classification of axial SpA should continue to primarily depend on the imaging features of 'active sacroiliitis' until more data are available regarding MRI features of structural damage in the sacroiliac joint and MRI features in the spine and their utility when used for classification purposes. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  17. Clinical routine implantation of a dual chamber pacemaker system designed for safe use with MRI: a single center, retrospective study on lead performance of Medtronic lead 5086MRI in comparison to Medtronic leads 4592-53 and 4092-58.

    Science.gov (United States)

    Wollmann, C G; Thudt, K; Vock, P; Globits, S; Mayr, H

    2011-12-01

    We report our experience concerning lead performance and re-surgery rate of the Medtronic EnRhythm MRI SureScan pacemaker system (MRI-PM) in comparison to standard pacemaker (PM) systems and leads used at our institution. All patients (except patients with transvenous left ventricular leads) with successful PM implantation performed at our institution from 1 March 2009 to 31 October 2009 were included in this analysis and followed until mid January 2010. Lead measurements (assessed at implantation, prehospital discharge interrogation (1st follow-up) and at the first scheduled out-patient follow-up (2nd follow-up) were compared between atrial leads 4592-53 cm and 5086MRI-52 cm (lead group 1), and between ventricular leads 4092-58 cm and 5086MRI-52 cm/-58 cm (lead group 2), respectively. Causes for re-operations were assessed and compared between patients with standard dual chamber PM (DC-PM) and the MRI-PM. A total of 140 patients (VVI-PM: 36 patients; DDD-PM: 102 patients; biventricular PM: 1 patient) were successfully implanted with a PM within the implantation period. Two patients with transvenous left ventricular leads were excluded from further analysis. In an atrial position, lead 4592 was implanted in 51 patients and lead 5086MRI-52 cm was implanted in 40 patients, respectively. Ventricular leads were lead 4092-58 cm (64 patients) and lead 5086MRI (41 patients), respectively. Patients were followed for 26 ± 11 weeks. Comparison of lead measurements of lead group 1 showed significant differences for pacing impedance and pacing threshold at implantation, and for sensing at the 2nd follow-up. Comparison of lead measurements within lead group 2 showed significant differences for pacing impedance at implantation, for pacing threshold at the 1st follow-up, and for sensing, pacing threshold, and impedance at the 2nd follow-up. All assessed mean values were favorable for all leads at any follow-up. The number of re-operations was high in

  18. Enzymatic activity toward poly(L-lactic acid) implants

    NARCIS (Netherlands)

    Schakenraad, J.M.; Hardonk, M.J.; Feijen, J.; Molenaar, I.; Nieuwenhuis, P.

    1990-01-01

    Tissue reactions toward biodegradable poly(L-lactic acid) implants were monitored by studying the activity pattern of seven enzymes as a function of time: alkaline phosphatase, acid phosphatase, -naphthyl acetyl esterase, -glucuronidase, ATP-ase, NADH-reductase, and lactate dehydrogenase. Cell types

  19. Brain Activity Associated with Emoticons: An fMRI Study

    Science.gov (United States)

    Yuasa, Masahide; Saito, Keiichi; Mukawa, Naoki

    In this paper, we describe that brain activities associated with emoticons by using fMRI. In communication over a computer network, we use abstract faces such as computer graphics (CG) avatars and emoticons. These faces convey users' emotions and enrich their communications. However, the manner in which these faces influence the mental process is as yet unknown. The human brain may perceive the abstract face in an entirely different manner, depending on its level of reality. We conducted an experiment using fMRI in order to investigate the effects of emoticons. The results show that right inferior frontal gyrus, which associated with nonverbal communication, is activated by emoticons. Since the emoticons were created to reflect the real human facial expressions as accurately as possible, we believed that they would activate the right fusiform gyrus. However, this region was not found to be activated during the experiment. This finding is useful in understanding how abstract faces affect our behaviors and decision-making in communication over a computer network.

  20. Effective dopant activation by susceptor-assisted microwave annealing of low energy boron implanted and phosphorus implanted silicon

    Science.gov (United States)

    Zhao, Zhao; David Theodore, N.; Vemuri, Rajitha N. P.; Lu, Wei; Lau, S. S.; Lanz, A.; Alford, T. L.

    2013-12-01

    Rapid processing and reduced end-of-range diffusion result from susceptor-assisted microwave (MW) annealing, making this technique an efficient processing alternative for electrically activating dopants within ion-implanted semiconductors. Sheet resistance and Hall measurements provide evidence of electrical activation. Susceptor-assisted MW annealing, of ion-implanted Si, enables more effective dopant activation and at lower temperatures than required for rapid thermal annealing (RTA). Raman spectroscopy and ion channeling analyses are used to monitor the extent of ion implantation damage and recrystallization. The presence and behavior of extended defects are monitored by cross-section transmission electron microscopy. Phosphorus implanted Si samples experience effective electrical activation upon MW annealing. On the other hand, when boron implanted Si is MW annealed, the growth of extended defects results in reduced crystalline quality that hinders the electrical activation process. Further comparison of dopant diffusion resulting from MW annealing and rapid thermal annealing is performed using secondary ion mass spectroscopy. MW annealed ion implanted samples show less end-of-range diffusion when compared to RTA samples. In particular, MW annealed P+ implanted samples achieve no visible diffusion and equivalent electrical activation at a lower temperature and with a shorter time-duration of annealing compared to RTA. In this study, the peak temperature attained during annealing does not depend on the dopant species or dose, for susceptor-assisted MW annealing of ion-implanted Si.

  1. Effective dopant activation by susceptor-assisted microwave annealing of low energy boron implanted and phosphorus implanted silicon

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Zhao; Vemuri, Rajitha N. P.; Alford, T. L., E-mail: TA@asu.edu [School of Matter, Transport, and Energy, Arizona State University, Tempe, Arizona 85287 (United States); David Theodore, N. [CHD-Fab, Freescale Semiconductor Inc., 1300 N. Alma School Rd., Chandler, Arizona 85224 (United States); Lu, Wei; Lau, S. S. [Department of Electrical Engineering, University of California, San Diego, California 92093 (United States); Lanz, A. [Department of Mathematics, Norfolk State University, Norfolk, Virginia 23504 (United States)

    2013-12-28

    Rapid processing and reduced end-of-range diffusion result from susceptor-assisted microwave (MW) annealing, making this technique an efficient processing alternative for electrically activating dopants within ion-implanted semiconductors. Sheet resistance and Hall measurements provide evidence of electrical activation. Susceptor-assisted MW annealing, of ion-implanted Si, enables more effective dopant activation and at lower temperatures than required for rapid thermal annealing (RTA). Raman spectroscopy and ion channeling analyses are used to monitor the extent of ion implantation damage and recrystallization. The presence and behavior of extended defects are monitored by cross-section transmission electron microscopy. Phosphorus implanted Si samples experience effective electrical activation upon MW annealing. On the other hand, when boron implanted Si is MW annealed, the growth of extended defects results in reduced crystalline quality that hinders the electrical activation process. Further comparison of dopant diffusion resulting from MW annealing and rapid thermal annealing is performed using secondary ion mass spectroscopy. MW annealed ion implanted samples show less end-of-range diffusion when compared to RTA samples. In particular, MW annealed P{sup +} implanted samples achieve no visible diffusion and equivalent electrical activation at a lower temperature and with a shorter time-duration of annealing compared to RTA. In this study, the peak temperature attained during annealing does not depend on the dopant species or dose, for susceptor-assisted MW annealing of ion-implanted Si.

  2. Indications and candidacy for active middle ear implants.

    Science.gov (United States)

    Wagner, F; Todt, I; Wagner, J; Ernst, A

    2010-01-01

    Currently, there are two active middle ear implants available commercially: the Vibrant Soundbridge system and the Carina system. A third active middle ear implant, the Esteem, is under clinical evaluation. All devices are indicated for patients with moderate-to-severe hearing loss. Because active middle ear implants are directly coupled to middle ear structures, many of the problems that patients with conventional hearing aids report, such as acoustic feedback, occlusion, and irritation of the outer ear canal, are avoided. In addition, AMEI patients perform well in background noise. However, indications for AMEIs are selective and candidates should be carefully evaluated before surgery. Before considering an AMEI, patients should be provided with conventional hearing aids. Only when benefit is insufficient and audiological selection criteria are met is further candidacy evaluation indicated. Since Colletti described coupling the Vibrant Soundbridge directly onto the round window membrane in 2006, the indications for the Vibrant Soundbridge have expanded and the VSB is implanted in patients with conductive and mixed hearing losses. Patients have often undergone middle ear surgery before. Especially mixed hearing loss cases with 30-60 dB HL sensorineural hearing impairment and 30-40 dB HL air-bone gaps may be helped by this new application.

  3. Grading Crohn disease activity with MRI: interobserver variability of MRI features, MRI scoring of severity, and correlation with Crohn disease endoscopic index of severity.

    Science.gov (United States)

    Tielbeek, Jeroen A W; Makanyanga, Jesica C; Bipat, Shandra; Pendsé, Doug A; Nio, C Yung; Vos, Frans M; Taylor, Stuart A; Stoker, Jaap

    2013-12-01

    The purpose of this article is to assess the interobserver variability for scoring MRI features of Crohn disease activity and to correlate two MRI scoring systems to the Crohn disease endoscopic index of severity (CDEIS). Thirty-three consecutive patients with Crohn disease undergoing 3-T MRI examinations (T1-weighted with IV contrast medium administration and T2-weighted sequences) and ileocolonoscopy within 1 month were independently evaluated by four readers. Seventeen MRI features were recorded in 143 bowel segments and were used to calculate the MR index of activity and the Crohn disease MRI index (CDMI) score. Multirater analysis was performed for all features and scoring systems using intraclass correlation coefficient (icc) and kappa statistic. Scoring systems were compared with ileocolonoscopy with CDEIS using Spearman rank correlation. Thirty patients (median age, 32 years; 21 women and nine men) were included. MRI features showed fair-to-good interobserver variability (intraclass correlation coefficient or kappa varied from 0.30 to 0.69). Wall thickness in millimeters, presence of edema, enhancement pattern, and length of the disease in each segment showed a good interobserver variability between all readers (icc = 0.69, κ = 0.66, κ = 0.62, and κ = 0.62, respectively). The MR index of activity and CDMI scores showed good reproducibility (icc = 0.74 and icc = 0.78, respectively) and moderate CDEIS correlation (r = 0.51 and r = 0.59, respectively). The reproducibility of individual MRI features overall is fair to good, with good reproducibility for the most commonly used features. When combined into the MR index of activity and CDMI score, overall reproducibility is good. Both scores show moderate agreement with CDEIS.

  4. Investigating the physiology of brain activation with MRI

    Science.gov (United States)

    Buxton, Richard B.; Uludag, Kamil; Dubowitz, David J.

    2004-04-01

    Functional magnetic resonance imaging (fMRI) has become a powerful tool for investigating the working human brain based on the blood oxygenation level dependent (BOLD) effect on the MR signal. However, despite the widespread use of fMRI techniques for mapping brain activation, the basic physiological mechanisms underlying the observed signal changes are still poorly understood. Arterial spin labeling (ASL) techniques, which measure cerebral blood flow (CBF) and the BOLD effect simultaneously, provide a useful tool for investigating these physiological questions. In this paper, recent results of studies manipulating the baseline CBF both pharmacologically and physiologically will be discussed. These data are consistent with a feed-forward mechanism of neurovascular coupling, and suggest that the CBF change itself may be a more robust reflection of neural activity changes than the BOLD effect. Consistent with these data, a new thermodynamic hypothesis is proposed for the physiological function of CBF regulation: maintenance of the [O2]/[CO2] concentration ratio at the mitochondria in order to preserve the free energy available from oxidative metabolism. A kinetic model based on this hypothesis provides a reasonable quantitative description of the CBF changes associated with neural activity and altered blood gases (CO2 and O2).

  5. Spatial heterogeneity analysis of brain activation in fMRI.

    Science.gov (United States)

    Gupta, Lalit; Besseling, René M H; Overvliet, Geke M; Hofman, Paul A M; de Louw, Anton; Vaessen, Maarten J; Aldenkamp, Albert P; Ulman, Shrutin; Jansen, Jacobus F A; Backes, Walter H

    2014-01-01

    In many brain diseases it can be qualitatively observed that spatial patterns in blood oxygenation level dependent (BOLD) activation maps appear more (diffusively) distributed than in healthy controls. However, measures that can quantitatively characterize this spatial distributiveness in individual subjects are lacking. In this study, we propose a number of spatial heterogeneity measures to characterize brain activation maps. The proposed methods focus on different aspects of heterogeneity, including the shape (compactness), complexity in the distribution of activated regions (fractal dimension and co-occurrence matrix), and gappiness between activated regions (lacunarity). To this end, functional MRI derived activation maps of a language and a motor task were obtained in language impaired children with (Rolandic) epilepsy and compared to age-matched healthy controls. Group analysis of the activation maps revealed no significant differences between patients and controls for both tasks. However, for the language task the activation maps in patients appeared more heterogeneous than in controls. Lacunarity was the best measure to discriminate activation patterns of patients from controls (sensitivity 74%, specificity 70%) and illustrates the increased irregularity of gaps between activated regions in patients. The combination of heterogeneity measures and a support vector machine approach yielded further increase in sensitivity and specificity to 78% and 80%, respectively. This illustrates that activation distributions in impaired brains can be complex and more heterogeneous than in normal brains and cannot be captured fully by a single quantity. In conclusion, heterogeneity analysis has potential to robustly characterize the increased distributiveness of brain activation in individual patients.

  6. Spatial heterogeneity analysis of brain activation in fMRI

    Directory of Open Access Journals (Sweden)

    Lalit Gupta

    2014-01-01

    Full Text Available In many brain diseases it can be qualitatively observed that spatial patterns in blood oxygenation level dependent (BOLD activation maps appear more (diffusively distributed than in healthy controls. However, measures that can quantitatively characterize this spatial distributiveness in individual subjects are lacking. In this study, we propose a number of spatial heterogeneity measures to characterize brain activation maps. The proposed methods focus on different aspects of heterogeneity, including the shape (compactness, complexity in the distribution of activated regions (fractal dimension and co-occurrence matrix, and gappiness between activated regions (lacunarity. To this end, functional MRI derived activation maps of a language and a motor task were obtained in language impaired children with (Rolandic epilepsy and compared to age-matched healthy controls. Group analysis of the activation maps revealed no significant differences between patients and controls for both tasks. However, for the language task the activation maps in patients appeared more heterogeneous than in controls. Lacunarity was the best measure to discriminate activation patterns of patients from controls (sensitivity 74%, specificity 70% and illustrates the increased irregularity of gaps between activated regions in patients. The combination of heterogeneity measures and a support vector machine approach yielded further increase in sensitivity and specificity to 78% and 80%, respectively. This illustrates that activation distributions in impaired brains can be complex and more heterogeneous than in normal brains and cannot be captured fully by a single quantity. In conclusion, heterogeneity analysis has potential to robustly characterize the increased distributiveness of brain activation in individual patients.

  7. Magnetic resonance imaging (MRI) evaluation of residual breast tissue following mastectomy and reconstruction with silicone implants.

    Science.gov (United States)

    Zippel, Douglas; Tsehmaister-Abitbol, Vered; Rundstein, Arie; Shalmon, Anat; Zbar, Andrew; Nardini, Gil; Novikov, Ilya; Sklair-Levy, Miri

    2015-01-01

    We present our use of magnetic resonance (MR) measurement to determine the amount of residual breast tissue (RBT) following total mastectomy with reconstruction. Breast MR images of 45 women who underwent surgery between January and November 2011 were reviewed. The cohort included therapeutic and prophylactic mastectomies. RBT was evaluated at four points with a digital caliper assessing T2-weighted and T1-weighted images. Patients undergoing mastectomy for carcinoma tended to have less RBT than in prophylactic surgery. Greater age and recent surgery both correlated with larger RBT. Variable thickness of RBT is demonstrable following mastectomy and implant reconstruction using MR imaging. Copyright © 2015 Elsevier Inc. All rights reserved.

  8. Coatings and surface modifications imparting antimicrobial activity to orthopedic implants.

    Science.gov (United States)

    Kargupta, Roli; Bok, Sangho; Darr, Charles M; Crist, Brett D; Gangopadhyay, Keshab; Gangopadhyay, Shubhra; Sengupta, Shramik

    2014-01-01

    Bacterial colonization and biofilm formation on an orthopedic implant surface is one of the worst possible outcomes of orthopedic intervention in terms of both patient prognosis and healthcare costs. Making the problem even more vexing is the fact that infections are often caused by events beyond the control of the operating surgeon and may manifest weeks to months after the initial surgery. Herein, we review the costs and consequences of implant infection as well as the methods of prevention and management. In particular, we focus on coatings and other forms of implant surface modification in a manner that imparts some antimicrobial benefit to the implant device. Such coatings can be classified generally based on their mode of action: surface adhesion prevention, bactericidal, antimicrobial-eluting, osseointegration promotion, and combinations of the above. Despite several advances in the efficacy of these antimicrobial methods, a remaining major challenge is ensuring retention of the antimicrobial activity over a period of months to years postoperation, an issue that has so far been inadequately addressed. Finally, we provide an overview of additional figures of merit that will determine whether a given antimicrobial surface modification warrants adoption for clinical use.

  9. Healing of complement activating Ti implants compared with non-activating Ti in rat tibia.

    Science.gov (United States)

    Harmankaya, N; Igawa, K; Stenlund, P; Palmquist, A; Tengvall, P

    2012-09-01

    Recent studies have revealed that ozone ultraviolet (UVO) illumination of titanium (Ti) implants improves bone-implant anchorage by altering the physico-chemical and immune activating properties of the titanium dioxide (TiO(2)) layer. In the present rat tibia model, the authors compared the early events of inflammation and bone formation around UVO-treated Ti and complement activating immunoglobin g (IgG)-coated Ti. Machined Ti and machined Ti coated with a physical vapour-deposited Ti layer were used as references. Screw-shaped test and reference implants were implanted into rat tibia and harvested after 1, 7 and 28 days. Messenger RNA expression of implant adhered cells and peri-implant tissue ~250 μm from the surface were subsequently analysed with regard to IL-1β, TNF-α, osteocalcin, cathepsin K, BMP-2 and PDGF. Separate implants were retrieved after 7 and 28 days for removal torque measurements, and histological staining and histomorphometric analysis of bone area and bone-to-implant contact. While enhanced expression of inflammatory markers, TNF-α and IL-1β, was observed on IgG-coated surfaces throughout the observation time, UVO-treated surfaces indicated a significantly lower early inflammatory response. In the early phases (1 and 7 days), the UVO-treated surfaces displayed a significantly higher expression of osteoblast markers BMP-2 and osteocalcin. In summary, complement activating Ti implants elicited a stronger inflammatory response than UVO-treated Ti, with low complement activation during the first week of healing. In spite of this, the UVO-treated Ti induced only marginally more bone growth outside the implants.

  10. Functional cine MRI of the abdomen for the assessment of implanted synthetic mesh in patients after incisional hernia repair: initial results

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Tanja [Ludwig-Maximilians-University Munich, Department of Clinical Radiology, Munich (Germany); Ludwig-Maximilians-University Munich, Department of Clinical Radiology, Klinikum Innenstadt, Munich (Germany); Ladurner, Roland; Mussack, Thomas [Ludwig-Maximilians-University Munich, Department of Surgery and Traumatology, Klinikum Innenstadt, Munich (Germany); Gangkofer, Alexander; Reiser, Maximilian; Lienemann, Andreas [Ludwig-Maximilians-University Munich, Department of Clinical Radiology, Munich (Germany)

    2007-12-15

    The aim of our study was to develop a method that allows the vizualiation and evaluation of implanted mesh in patients after incisional hernia repair with MRI. Furthermore, we assessed problems typically related with mesh implantation like adhesions and muscular atrophy. We enrolled 28 patients after incisional hernia repair. In 10 patients mesh implantation was done by laparoscopy (expanded polytetrafluoroethylene=ePTFE mesh) and in 18 by laparotomy (polypropylene mesh). Functional MRI was performed on a 1.5-T system in supine position. Sagittal and axial TrueFISP images of the entire abdomen were acquired with the patient repeatedly straining. Evaluation included: correct position and intact fixation of the mesh, furthermore visceral adhesions, recurrent hernia and atrophy of the rectus muscle. The ePTFE mesh was visible in all cases; the polypropylene mesh was not detectable. In seven of the ten ePTFE meshes the fixation was not intact; two recurrent hernias were detected. Twenty of 28 patients had intraabdominal adhesions. In 5 cases mobility of the abdominal wall was reduced, and 16 patients showed an atropy of the rectus muscle. Functional cine MRI is a suitable method for follow-up studies in patients after hernia repair. ePTFE meshes can be visualized directly, and typical complications like intestinal adhesions and abdominal wall dysmotility can be assessed reliably. (orig.)

  11. SU-D-207B-04: Morphological Features of MRI as a Correlate of Capsular Contracture in Breast Cancer Patients with Implant-Based Reconstructions

    Energy Technology Data Exchange (ETDEWEB)

    Tyagi, N; Sutton, E; Hunt, M; Apte, A; Zhang, J; Oh, J; Mechalakos, J; Mehrara, B; Matros, E; Ho, A [Mem Sloan-Kettering Cancer Ctr, New York, NY (United States)

    2016-06-15

    Purpose: Capsular contracture (CC) is a serious complication in patients receiving implant-based reconstruction for breast cancer. The goal of this study was to identify image-based correlates of CC using MRI imaging in breast cancer patients who received both MRI and clinical evaluation following reconstructive surgery. Methods: We analyzed a retrospective dataset of 50 patients who had both a diagnostic MR and a plastic surgeon’s evaluations of CC score (Baker’s score) within a six month period following mastectomy and reconstructive surgery. T2w sagittal MRIs (TR/TE = 3500/102 ms, slice thickness = 4 mm) were used for morphological shape features (roundness, eccentricity, solidity, extent and ratio-length) and histogram features (median, skewness and kurtosis) of the implant and the pectoralis muscle overlying the implant. Implant and pectoralis muscles were segmented in 3D using Computation Environment for Radiological Research (CERR) and shape and histogram features were calculated as a function of Baker’s score. Results: Shape features such as roundness and eccentricity were statistically significant in differentiating grade 1 and grade 2 (p = 0.009; p = 0.06) as well as grade 1 and grade 3 CC (p = 0.001; p = 0.006). Solidity and extent were statistically significant in differentiating grade 1 and grade 3 CC (p = 0.04; p = 0.04). Ratio-length was statistically significant in differentiating all grades of CC except grade 2 and grade 3 that showed borderline significance (p = 0.06). The muscle thickness, median intensity and kurtosis were significant in differentiating between grade 1 and grade 3 (p = 0.02), grade 1 and grade 2 (p = 0.03) and grade 1 and grade 3 (p = 0.01) respectively. Conclusion: Morphological shape features described on MR images were associated with the severity of CC. MRI may be important in objectively evaluating outcomes in breast cancer patients who undergo implant reconstruction.

  12. Advanced metal artifact reduction MRI of metal-on-metal hip resurfacing arthroplasty implants: compressed sensing acceleration enables the time-neutral use of SEMAC

    Energy Technology Data Exchange (ETDEWEB)

    Fritz, Jan; Thawait, Gaurav K. [Johns Hopkins University School of Medicine, Russell H. Morgan Department of Radiology and Radiological Science, Section of Musculoskeletal Radiology, Baltimore, MD (United States); Fritz, Benjamin [University of Freiburg, Department of Radiology, Freiburg im Breisgau (Germany); Raithel, Esther; Nittka, Mathias [Siemens Healthcare GmbH, Erlangen (Germany); Gilson, Wesley D. [Siemens Healthcare USA, Inc., Baltimore, MD (United States); Mont, Michael A. [Cleveland Clinic Foundation, Department of Orthopedic Surgery, Cleveland, OH (United States)

    2016-10-15

    Compressed sensing (CS) acceleration has been theorized for slice encoding for metal artifact correction (SEMAC), but has not been shown to be feasible. Therefore, we tested the hypothesis that CS-SEMAC is feasible for MRI of metal-on-metal hip resurfacing implants. Following prospective institutional review board approval, 22 subjects with metal-on-metal hip resurfacing implants underwent 1.5 T MRI. We compared CS-SEMAC prototype, high-bandwidth TSE, and SEMAC sequences with acquisition times of 4-5, 4-5 and 10-12 min, respectively. Outcome measures included bone-implant interfaces, image quality, periprosthetic structures, artifact size, and signal- and contrast-to-noise ratios (SNR and CNR). Using Friedman, repeated measures analysis of variances, and Cohen's weighted kappa tests, Bonferroni-corrected p-values of 0.005 and less were considered statistically significant. There was no statistical difference of outcomes measures of SEMAC and CS-SEMAC images. Visibility of implant-bone interfaces and pseudocapsule as well as fat suppression and metal reduction were ''adequate'' to ''good'' on CS-SEMAC and ''non-diagnostic'' to ''adequate'' on high-BW TSE (p < 0.001, respectively). SEMAC and CS-SEMAC showed mild blur and ripple artifacts. The metal artifact size was 63 % larger for high-BW TSE as compared to SEMAC and CS-SEMAC (p < 0.0001, respectively). CNRs were sufficiently high and statistically similar, with the exception of CNR of fluid and muscle and CNR of fluid and tendon, which were higher on intermediate-weighted high-BW TSE (p < 0.005, respectively). Compressed sensing acceleration enables the time-neutral use of SEMAC for MRI of metal-on-metal hip resurfacing implants when compared to high-BW TSE and image quality similar to conventional SEMAC. (orig.)

  13. Muscular activity may improve in edentulous patients after implant treatment.

    Science.gov (United States)

    Afrashtehfar, Kelvin I; Schimmel, Martin

    2016-12-01

    Data sourcesMedline via Pubmed and the Cochrane Library were searched from January 1980 to September 2013. This was complemented by a manual search of the magazines Deutsche Zahnaerztliche Zeitung, Quintessenz, Zeitschrift für Zahnärztliche Implantologie, Schweizerische Monatszeitschrift and Implantologie. Additionally, the list of reference s of all selected full-text articles and related reviews were further scrutinised for potential included studies in English or German.Study selectionThree review authors independently searched for clinical trials that assessed the muscular activity in the intervention groups: edentulous patients treated with implant-overdentures (IODs) and implant-supported fixed dental prostheses (ISFDPs) and the comparison groups: dentates and edentulous patients treated with mucosa-borne complete removable dental prostheses (CRDPs).Data extraction and synthesisThe primary outcome was the muscular activity (measured by electromyography [EMG]) in masseter or temporalis muscle of the participants during clenching and chewing. The data extraction of each included study consisted of author, year, age range, treatment, number of participants, number of implants inserted, arch treated, opposite jaw, kind and side of the muscles that were measured. EMG gain or loss (unit measured: volt) was considered by using the effect size. For the meta-analyses only the studies that included masseter muscle measured separately from temporalis were considered. Concerning the side of measurement (right and left side measured together or right and left side measured separately), only the dominant type in each category was included.ResultsSixteen articles, out of the initial 646 retrieved abstracts, were analysed. The muscular activity of edentulous subjects increased after implant support therapy during clenching (effect size [ES]: 2.18 [95% confidence interval [CI]: 1.14, 3.23]) and during chewing (ES: 1.45 [95 % CI: 1.21, 1.69]). In addition, the pooled EMG

  14. Fibroblastic activities post implantation of cobalt chromium alloy and pure germanium in rabbits.

    Science.gov (United States)

    Carter, J M; Natiella, J R; Baier, R E; Natiella, R R

    1984-02-01

    Different preimplantation surface finishes were applied to surgical vitallium discs and germanium prisms implanted for 20 days within the back muscles of adult rabbits. Histopathologic analysis of the numbers of nuclei of active fibroblasts immediately adjacent to the implants was carried out. The mean apparent volume fractions (MAVF) for the subdermal implant sites were found to depend on the surface cleanliness of the implant, the cleanest or highest-surface-energy surfaces giving the highest MAVF values for active fibroblasts.

  15. Motion or activity: their role in intra- and inter-subject variation in fMRI

    DEFF Research Database (Denmark)

    Lund, Torben E; Nørgaard, Minna D; Rostrup, Egill

    2005-01-01

    Functional MRI (fMRI) carries the potential for non-invasive measurements of brain activity. Typically, what are referred to as activation images are actually thresholded statistical parametric maps. These maps possess large inter-session variability. This is especially problematic when applying ...

  16. Chronotype Modulates Language Processing-Related Cerebral Activity during Functional MRI (fMRI.

    Directory of Open Access Journals (Sweden)

    Jessica Rosenberg

    Full Text Available Based on individual daily physiological cycles, humans can be classified as early (EC, late (LC and intermediate (IC chronotypes. Recent studies have verified that chronotype-specificity relates to performance on cognitive tasks: participants perform more efficiently when tested in the chronotype-specific optimal time of day than when tested in their non-optimal time. Surprisingly, imaging studies focussing on the underlying neural mechanisms of potential chronotype-specificities are sparse. Moreover, chronotype-specific alterations of language-related semantic processing have been neglected so far.16 male, healthy ECs, 16 ICs and 16 LCs participated in a fast event-related functional Magnetic Resonance Imaging (fMRI paradigm probing semantic priming. Subjects read two subsequently presented words (prime, target and were requested to determine whether the target word was an existing word or a non-word. Subjects were tested during their individual evening hours when homeostatic sleep pressure and circadian alertness levels are high to ensure equal entrainment.Chronotype-specificity is associated with task-performance and brain activation. First, ECs exhibited slower reaction times than LCs. Second, ECs showed attenuated BOLD responses in several language-related brain areas, e.g. in the left postcentral gyrus, left and right precentral gyrus and in the right superior frontal gyrus. Additionally, increased BOLD responses were revealed for LCs as compared to ICs in task-related areas, e.g. in the right inferior parietal lobule and in the right postcentral gyrus.These findings reveal that even basic language processes are associated with chronotype-specific neuronal mechanisms. Consequently, results might change the way we schedule patient evaluations and/or healthy subjects in e.g. experimental research and adding "chronotype" as a statistical covariate.

  17. Diagnosis of Placenta Previa and Placenta Implantation With MRI%前置胎盘及胎盘植入的MRI诊断

    Institute of Scientific and Technical Information of China (English)

    刘静; 罗莎

    2015-01-01

    ObjectiveTo explore the application value of MRI in the prenatal diagnosis of front disc and implantation of placenta previa. Methods Retrospective analysis of our hospital 16 cases of placental MRI examination conifrmed byoperation and pathology after cesarean section. Results8 cases of central placenta previa, 5 cases of partialplacenta previa, 2 cases of marginal placenta previa, low-lying placenta 1 cases, 2 cases of Placenta Adhesion, 2 cases of placenta implantation, including 1 cases of transmural implantation, placenta in the posterior inferior wall in 11 cases, 4 cases of anterior inferior wall, 2 cases of lateral wall.Conclusion MRI on placenta previa placenta implantation in the clinical diagnosis and timely and reasonable treatment plan have some certain signiifcance.%目的:探讨MRI在诊断产前前置前盘及植入性前置胎盘的应用价值。方法剖宫产后回顾性分析我院经手术及病理证实的16例胎盘MRI检查。结果中央性前置胎盘8例,部分性前置胎盘5例,边缘性前置胎盘2例,低置胎盘1例,胎盘粘连2例,胎盘植入2例,其中1例透壁植入,胎盘位于后下壁11例,前下壁4例,侧壁2例。结论 MRI对前置胎盘及胎盘植入诊断对临床及时合理制定治疗方案有一定意义。

  18. TU-AB-201-11: A Novel Theoretical Framework for MRI-Only Image Guided LDR Prostate and Breast Brachytherapy Implant Dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Soliman, A; Elzibak, A; Fatemi, A; Safigholi, H; Ravi, A; Morton, G; Song, W [Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, Ontario (Canada); Han, D [Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, Ontario (Canada); University of California, San Diego, La Jolla, CA (United States)

    2015-06-15

    Purpose: To propose a novel framework for accurate model-based dose calculations using only MR images for LDR prostate and breast seed implant brachytherapy. Methods: Model-based dose calculation methodologies recommended by TG-186 require further knowledge about specific tissue composition, which is challenging with MRI. However, relying on MRI-only for implant dosimetry would reduce the soft tissue delineation uncertainty, costs, and uncertainties associated with multi-modality registration and fusion processes. We propose a novel framework to address this problem using quantitative MRI acquisitions and reconstruction techniques. The framework includes three steps: (1) Identify the locations of seeds(2) Identify the presence (or absence) of calcification(s)(3) Quantify the water and fat content in the underlying tissueSteps (1) and (2) consider the sources that limit patient dosimetry, particularly the inter-seed attenuation and the calcified regions; while step (3) targets the quantification of the tissue composition to consider the heterogeneities in the medium. Our preliminary work has shown that the seeds and the calcifications can be identified with MRI using both the magnitude and the phase images. By employing susceptibility-weighted imaging with specific post-processing techniques, the phase images can be further explored to distinguish the seeds from the calcifications. Absolute quantification of tissue, water, and fat content is feasible and was previously demonstrated in phantoms and in-vivo applications, particularly for brain diseases. The approach relies on the proportionality of the MR signal to the number of protons in an image volume. By employing appropriate correction algorithms for T1 - and T2*-related biases, B1 transmit and receive field inhomogeneities, absolute water/fat content can be determined. Results: By considering calcification and interseed attenuation, and through the knowledge of water and fat mass density, accurate patient

  19. Phosphorous transient enhanced diffusion suppression and activation enhancement with cluster carbon co-implantation

    Energy Technology Data Exchange (ETDEWEB)

    Nakashima, Yoshiki; Hamamoto, Nariaki; Nagayama, Tsutomu; Koga, Yuji; Umisedo, Sei; Kawamura, Yasunori; Hashimoto, Masahiro; Onoda, Hiroshi [Nissin Ion Equipment Co., Ltd., 575 Kuze Tonoshiro-cho, Minami-ku, Kyoto, 601-8205 (Japan)

    2012-11-06

    Carbon co-implantation is well known as an effective method for suppressing boron/phosphorous transient enhanced diffusion (TED). Germanium pre-amorphization implantation (PAI) is usually applied prior to carbon co-implantation for suppressing channeling tail of dopants. In this study, cluster carbon was applied instead of the combination of germanium PAI and monomer carbon co-implantation prior to phosphorous implantation. Dependence of phosphorous activation and TED on amorphous layer thickness, carbon dose, carbon distribution and substrate temperature have been investigated. Cluster carbon implantation enables thick amorphous layer formation and TED suppression at the same time and low temperature implantation enhances the ability of amorphous layer formation so that shallow junction and low Rs can be achieved without Ge implantation.

  20. MRI of pituitary macroadenomas with reference to hormonal activity

    Energy Technology Data Exchange (ETDEWEB)

    Lundin, P.; Nyman, R. (Akademiska Sjukhuset, Uppsala (Sweden). Dept. of Diagnostic Radiology); Burmann, P. (Akademiska Sjukhuset, Uppsala (Sweden). Dept. of Internal Medicine); Lundberg, P.O. (Akademiska Sjukhuset, Uppsala (Sweden). Dept. of Neurology)

    1992-02-01

    In 115 patients with pituitary macroadenomas, the findings on mid-field MRI were correlated with the hormonal activity of the tumours. Adenomas secreting growth hormone (GH), prolactin (PRL) and clinically nonsecretory adenomas were studied. Tumour size, invasiveness and signal intensity patterns were recorded. Relaxation times and ratios of signal intensity and proton density (relative to the corpus callosum) were analysed in areas of apparently solid tissue in a subgroup of 59 previously untreated patients. Invasiveness was more common in PRL- and GH-secreting adenomas than in the nonsecreting ones. Diffuse invasion of the base of the skull was most common in prolactinomas, and associated with a lower frequency of suprasellar tumour extension. In prolactinomas, a correlation was found between the maximum serum PRL level and tumour size. Haemorrhagic, cystic or necrotic areas were less common in GH-secreting tumours than in the other types. Haemorrhage was more common in prolactinomas than in nonsecreting tumours. MR parameters were similar in prolactinomas and nonsecreting adenomas, but indicated a smaller amount of water in GH-secreting tumours. (orig.).

  1. Update on CLiMRI activities and Auto 21

    Energy Technology Data Exchange (ETDEWEB)

    Jackman, J. [Natural Resources Canada, Ottawa, ON (Canada). CANMET Energy Technology Centre

    2001-07-01

    The Canadian Lightweight Materials Research Initiative (CLiMRI) program and the Auto21 Network of Centres of Excellence were created to improve energy efficiency in vehicles, reduce emissions and provide economic benefits to Canada from next generation vehicles and systems. The objective is to increase energy efficiency of vehicles using lightweight materials and efficient design components. Activities include improved engine performance of materials, improved manufacturing technologies, and improved components and vehicle systems. The program involves a comprehensive database on the mechanical properties of magnesium alloys AE42 and AM60B. Data on thermophysical properties is also available for die-cast process modeling. Potential applications of alumina-based sol-gel coatings for aluminium heat exchanger panels have been identified. The yield strength of magnesium extrusion alloys has been increased by more than 15 per cent through grain refinement techniques. The project is also designed to work on improving the corrosion performance of magnesium-based alloys, with particular focus through USAMP project for the development of a magnesium engine cradle. Test work has been carried out on two alloys and 10 coating have been chosen for trial. tabs., figs.

  2. MRI grading method for active and chronic spinal changes in spondyloarthritis

    Energy Technology Data Exchange (ETDEWEB)

    Madsen, K.B. [Department of Radiology, Aarhus University Hospital, Aarhus Sygehus (Denmark); Jurik, A.G., E-mail: anne.jurik@aarhus.rm.d [Department of Radiology, Aarhus University Hospital, Aarhus Sygehus (Denmark)

    2010-01-15

    Aim: To describe a magnetic resonance imaging (MRI) grading method for both active and chronic spondyloarthritis (SpA) changes in the spine, to test its validity, and compare chronic MRI scores with findings obtained by radiography. Material and methods: A total of 91 patients (41 males; 50 females) with back pain fulfilling the European Spondylarthropathy Study Group (ESSG) criteria for SpA were examined using MRI and radiography of the spine. The mean age was 36.7 years (range 16-51 years) and symptom duration was between 3 and 27 years. The MRI images were assessed for signs of disease activity (bone marrow oedema at the vertebral plates and costo-vertebral joints) and chronic structural changes [syndesmophytes/vertebral fusion, erosion, and fatty marrow deposition (FMD)]. The interobserver agreement was analysed based on 37 examinations. Radiographs were assessed for the presence of shiny corners, vertebral squaring, syndesmophytes/fusion, and erosion. Results: The interobserver agreement for the assessed MRI abnormalities was acceptable, with kappa values between 0.62 and 0.77. A total of 56 patients had SpA-related spinal abnormalities as depicted using MRI. The total chronic MRI score was not significantly related to the radiographic score, mainly because syndesmophytes were difficult to detect by MRI and FMD was only visualized by MRI. However, FMD was significantly related to the total radiographic score and vertebral squaring. Conclusion: The described MRI grading method was reliable for assessing both disease activity and chronic changes. MRI is promising for estimating chronic changes, but cervical radiography may still be needed. FMD seems to be an important sign of chronicity.

  3. Neural Activity Elicited by a Cognitive Task can be Detected in Single-Trials with Simultaneous Intracerebral EEG-fMRI Recordings.

    Science.gov (United States)

    Saignavongs, Mani; Ciumas, Carolina; Petton, Mathilde; Bouet, Romain; Boulogne, Sébastien; Rheims, Sylvain; Carmichael, David W; Lachaux, Jean-Philippe; Ryvlin, Philippe

    2017-02-01

    Recent studies have shown that it is feasible to record simultaneously intracerebral EEG (icEEG) and functional magnetic resonance imaging (fMRI) in patients with epilepsy. While it has mainly been used to explore the hemodynamic changes associated with epileptic spikes, this approach could also provide new insight into human cognition. However, the first step is to ensure that cognitive EEG components, that have lower amplitudes than epileptic spikes, can be appropriately detected under fMRI. We compared the high frequency activities (HFA, 50-150[Formula: see text]Hz) elicited by a reading task in icEEG-only and subsequent icEEG-fMRI in the same patients ([Formula: see text]), implanted with depth electrodes. Comparable responses were obtained, with 71% of the recording sites that responded during the icEEG-only session also responding during the icEEG-fMRI session. For all the remaining sites, nearby clusters (distant of 7[Formula: see text]mm or less) also demonstrated significant HFA increase during the icEEG-fMRI session. Significant HFA increases were also observable at the single-trial level in icEEG-fMRI recordings. Our results show that low-amplitude icEEG signal components such as cognitive-induced HFAs can be reliably recorded with simultaneous fMRI. This paves the way for the use of icEEG-fMRI to address various fundamental and clinical issues, notably the identification of the neural correlates of the BOLD signal.

  4. Joint sparse representation of brain activity patterns in multi-task fMRI data.

    Science.gov (United States)

    Ramezani, M; Marble, K; Trang, H; Johnsrude, I S; Abolmaesumi, P

    2015-01-01

    A single-task functional magnetic resonance imaging (fMRI) experiment may only partially highlight alterations to functional brain networks affected by a particular disorder. Multivariate analysis across multiple fMRI tasks may increase the sensitivity of fMRI-based diagnosis. Prior research using multi-task analysis in fMRI, such as those that use joint independent component analysis (jICA), has mainly assumed that brain activity patterns evoked by different tasks are independent. This may not be valid in practice. Here, we use sparsity, which is a natural characteristic of fMRI data in the spatial domain, and propose a joint sparse representation analysis (jSRA) method to identify common information across different functional subtraction (contrast) images in data from a multi-task fMRI experiment. Sparse representation methods do not require independence, or that the brain activity patterns be nonoverlapping. We use functional subtraction images within the joint sparse representation analysis to generate joint activation sources and their corresponding sparse modulation profiles. We evaluate the use of sparse representation analysis to capture individual differences with simulated fMRI data and with experimental fMRI data. The experimental fMRI data was acquired from 16 young (age: 19-26) and 16 older (age: 57-73) adults obtained from multiple speech comprehension tasks within subjects, where an independent measure (namely, age in years) can be used to differentiate between groups. Simulation results show that this method yields greater sensitivity, precision, and higher Jaccard indexes (which measures similarity and diversity of the true and estimated brain activation sources) than does the jICA method. Moreover, superiority of the jSRA method in capturing individual differences was successfully demonstrated using experimental fMRI data.

  5. Diagnostic value of MRI for placenta previa with placental implantation%磁共振在前置胎盘伴胎盘植入中的诊断价值

    Institute of Scientific and Technical Information of China (English)

    高继勇; 梅海炳; 高军

    2011-01-01

    目的 探讨磁共振扫描对前置胎盘伴植入的诊断价值.方法 23 例临床诊断前置胎盘的患者行MRI平扫,术后进行回顾分析.结果 胎盘子宫分界正常10 例,粘连3 例,植入8 例,穿通2 例.术后及病理诊断为正常6例,粘连4 例,植入11 例,穿通2 例.术前MRI 诊断为植入及穿通者,与术后相符,术后诊断为植入者2 例报告为粘连,1 例报告为正常.术后诊断为粘连者,3 例术前报告为正常.结论 磁共振对前置胎盘伴有胎盘植入及穿通能提供准确的诊断.%Objective To investigate the MRI diagnostic value for placenta previa with placental implantation. Methods MRI of 23 patients with placenta previa was retrospectively analyzed. Results The boundaries of the placenta were clear from (10), adherent with (3), implanted in (8), or penetrating through (2) the myometrium on MRI. 6 cases were diagnosed as normal after surgery, 4 cases of adhesion, 11 cases were implanted, 2 cases of penetrating. The MRI diagnosis of placental implantation (8) and penetration (2) was confirmed operatively. Two cases of implantation were erroneously classified as placental adhesion and 1 case was misinterpreted as normal. 3 out of 4 cases of placental adhesion were missed on MRI. Conclusion MRI is helpful in diagnosing placental implantation.

  6. MR implant labelling and its use in clinical MRI practice; MR-Implantatkennzeichnungen und ihre Anwendung in der klinischen MRT-Praxis

    Energy Technology Data Exchange (ETDEWEB)

    Muehlenweg, M. [Krankenhaus Martha-Maria Halle-Doelau, Institut fuer Radiologie, Halle (Saale) (Germany); Schaefers, G. [MR:comp GmbH, Gelsenkirchen (Germany)

    2015-08-15

    Before a magnetic resonance imaging (MRI) examination, implants in patients must be cleared for MR safety in order to exclude the risk of possible severe injuries and implant malfunction in an MR environment. The general contraindication for measurements of patients with implants still applies; however, in the recent past a way has been found to legally circumvent this contraindication. For this purpose special conditions are required: explicit implant identification and the original manufacturer's labelling are necessary, the required conditions for conditionally MR safe implants must be assured and a risk-benefit analysis with appropriate explanation to the patient has to be performed. This process can be very complex as the implants are often poorly documented and detailed information on the implant MR labelling is also often outdated or not easy to interpret. This article provides information about legal and normative principles of MR measurement of patients with implants. The possible physical interactions with implants will be briefly dealt with as well as possible strategies for better identification and investigation of implants and MR labelling. General approaches for minimizing the risk will be discussed using some examples. The second part deals with the content of MR implant labelling and the current test standards. Furthermore, the additional information from the operating instructions of the MR scanner that are necessary for the interpretation of the MR implant labelling, will be explained. The article concludes with an explanation of the current pattern for MR labelling of implants from the U.S. Food and Drug Administration (FDA) and an exemplary application. (orig.) [German] Implantate in Patienten muessen vor einer MR-Untersuchung auf MR-Sicherheit abgeklaert werden, um moegliche z. T. schwere Verletzungen und Implantatfehlfunktionen in einer MR-Umgebung weitestgehend auszuschliessen. Es gilt unveraendert die generelle Kontraindikation von

  7. Receptor activator of nuclear factor kappa B (RANK as a determinant of peri-implantitis

    Directory of Open Access Journals (Sweden)

    Rakić Mia

    2013-01-01

    Full Text Available Background/Aim. Peri-implantitis presents inflammatory process that affects soft and hard supporting tissues of osseointegrated implant based on inflammatory osteoclastogenesis. The aim of this study was to investigate whether receptor activator of nuclear factor kappa B (RANK concentrations in peri-implant crevicular fluid could be associated with clinical parameters that reflect inflammatory nature of peri-implantitis. Methods. The study included 67 patients, 22 with diagnosed peri-implantitis, 22 persons with healthy peri-implant tissues and 23 patients with periodontitis. Clinical parameters from each patient were recorded and samples of peri-implant/gingival crevicular fluid were collected for the enzyme-linked immunosorbent assay (ELISA analysis. Results. RANK concentration was significantly increased in samples from the patients with periimplantitis when compared to healthy implants (p < 0.0001, where the average levels were 9 times higher. At the same time RANK concentration was significantly higher in periimplantitis than in periodontitis sites (p < 0.0001. In implant patients pocket depths and bleeding on probing values were positively associated with high RANK concentrations (p < 0.0001. Conclusion. These results revealed association of increased RANK concentration in samples of periimplant/ gingival crevicular fluid with peri-implant inflammation and suggests that RANK could be a pathologic determinant of peri-implantitis, thereby a potential parameter in assessment of peri-implant tissue inflammation and a potential target in designing treatment strategies.

  8. Cyclodextrin modified PLLA parietal reinforcement implant with prolonged antibacterial activity.

    Science.gov (United States)

    Vermet, G; Degoutin, S; Chai, F; Maton, M; Flores, C; Neut, C; Danjou, P E; Martel, B; Blanchemain, N

    2017-02-12

    The use of textile meshes in hernia repair is widespread in visceral surgery. Though, mesh infection is a complication that may prolong the patient recovery period and consequently presents an impact on public health economy. Such concern can be avoided thanks to a local and extended antibiotic release on the operative site. In recent developments, poly-l-lactic acid (PLLA) has been used in complement of polyethyleneterephthalate (Dacron®) (PET) or polypropylene (PP) yarns in the manufacture of semi-resorbable parietal implants. The goal of the present study consisted in assigning drug reservoir properties and prolonged antibacterial effect to a 100% PLLA knit through its functionalization with a cyclodextrin polymer (polyCD) and activation with ciprofloxacin. The study focused i) on the control of degree of polyCD functionalization of the PLLA support and on its physical and biological characterization by Scanning Electron Microscopy (SEM), Differential Scanning Calorimetry (DSC) and cell viability, ii) on the understanding of drug/meshes interaction using mathematic model and iii) on the correlation between drug release studies in phosphate buffer saline (PBS) and microbiological evaluation of meshes and release medium against E. coli and S. aureus. All above mentioned tests highlighted the contribution of polyCD on the improved performances of the resulting antibacterial implantable material.

  9. In vitro assessment of MRI safety at 1.5 T and 3.0 T for bone-anchored hearing aid implant

    Energy Technology Data Exchange (ETDEWEB)

    Yeon, Kyoo Jin; KIm, Hyun Soo; Lee, Seung Keun [Dept. of Radiology, Samsung Medical Center, Seoul (Korea, Republic of); Lee, Tae Soo [Dept. of Biomedical Engineering, Chungbuk National University, Cheongju (Korea, Republic of)

    2017-03-15

    The aim of this study was to evaluate Magnetic Resonance Imaging safety by measuring the translational attraction, torque and susceptibility artifact for Bone-Anchored Hearing Aid (BAHA) implant at 1.5 T and 3.0 T MRI by standard criteria. In vitro assessment tools were made of acrylic-resin by American Society for Testing and Materials (ASTM) F2052-06 and F2119-07 standard. Translational attraction of BAHA implant was measured by the maximum deflection angle at 96 cm position, where the magnetically induced deflection was the greatest. The torque was assessed by the qualitative criteria of evaluating the alignment and rotation pattern, when the BAHA implant was positioned on a line with 45° intervals inside the circular container in the center of the bore. The susceptibility artifact images were obtained using the hanged test tool, which was filled with CuSO4 solution. And then the artifact size was measured using Susceptibility Artifact Measurement (SAM) software. In results, the translational attraction was 0 mm at both 1.5 T and 3.0 T and the torque was 0(no torque) at 1.5 T, and +1(mild torque) at 3.0 T. The size of susceptibility artifacts was between 13.20 mm and 38.91 mm. Therefore, The BAHA implant was safe for the patient in clinical MR environment.

  10. Lateralisation of cerebral response to active acupuncture in patients with unilateral ischaemic stroke: an fMRI study

    National Research Council Canada - National Science Library

    Huang, Yong; Chen, Jun-Qi; Lai, Xin-Sheng; Tang, Chun-Zhi; Yang, Jun-Jun; Chen, Hua; Wu, Jun-Xian; Xiao, Hui-Ling; Qu, Shan-Shan; Zhang, Yi-Dan; Zhang, Zhang-Jin

    2013-01-01

    Acupuncture is beneficial in treating stroke neuropsychiatric symptoms. The present study aimed to identify functional brain response to active acupuncture in patients with unilateral ischaemic stroke using functional MRI (fMRI...

  11. Whole-Body MRI versus PET in assessment of multiple myeloma disease activity.

    LENUS (Irish Health Repository)

    Shortt, Conor P

    2009-04-01

    The purpose of this study was to compare FDG PET; whole-body MRI; and the reference standard, bone marrow aspiration and biopsy, to determine the best imaging technique for assessment of disease activity in multiple myeloma.

  12. EEG-fMRI Bayesian framework for neural activity estimation: a simulation study

    Science.gov (United States)

    Croce, Pierpaolo; Basti, Alessio; Marzetti, Laura; Zappasodi, Filippo; Del Gratta, Cosimo

    2016-12-01

    Objective. Due to the complementary nature of electroencephalography (EEG) and functional magnetic resonance imaging (fMRI), and given the possibility of simultaneous acquisition, the joint data analysis can afford a better understanding of the underlying neural activity estimation. In this simulation study we want to show the benefit of the joint EEG-fMRI neural activity estimation in a Bayesian framework. Approach. We built a dynamic Bayesian framework in order to perform joint EEG-fMRI neural activity time course estimation. The neural activity is originated by a given brain area and detected by means of both measurement techniques. We have chosen a resting state neural activity situation to address the worst case in terms of the signal-to-noise ratio. To infer information by EEG and fMRI concurrently we used a tool belonging to the sequential Monte Carlo (SMC) methods: the particle filter (PF). Main results. First, despite a high computational cost, we showed the feasibility of such an approach. Second, we obtained an improvement in neural activity reconstruction when using both EEG and fMRI measurements. Significance. The proposed simulation shows the improvements in neural activity reconstruction with EEG-fMRI simultaneous data. The application of such an approach to real data allows a better comprehension of the neural dynamics.

  13. Electrical activation of ultralow energy As implants in Si

    Science.gov (United States)

    Whelan, S.; Privitera, V.; Mannino, G.; Italia, M.; Bongiorno, C.; La Magna, A.; Napolitani, E.

    2001-10-01

    Arsenic implants performed in Si at ultralow energy have been extensively studied with structural, chemical, and electrical analysis. The near-surface damage annealing and its influence on the electrical activation of ultrashallow As in Si as a function of the anneal ambient has been investigated. Double alignment medium energy ion scattering, high resolution transmission electron microscopy, and low energy secondary ion mass spectrometry have been used to assess the dopant behavior and crystal recovery in the near-surface regions. The electrical activation of As in Si has been measured with spreading resistance profiling, four point probe, and van der Pauw methods. Major redistribution of the dopant into the SiO2-Si interface region occurred during crystal regrowth of the damaged Si layer. An inactive meta-stable As solid solution was formed in the near-surface region after amorphous layer regrowth. Electrical activation of the dopant occurred upon dissociation of the As solid solution, when the dopant concentration fell to the steady state level. The As diffusion observed has been shown to be enhanced for short (10 s) anneal times at 1100 °C. When annealing at high temperature in an oxidizing ambient the dopant is retained at a high concentration in the solid and a higher level of electrical activation is observed. Significant outdiffusion of the dopant is observed during high temperature annealing in nonoxidizing conditions which reduced the level of activation.

  14. Immediate restoration of NobelActive implants placed into fresh extraction sites in the anterior maxilla.

    Science.gov (United States)

    Bell, Christopher; Bell, Robert E

    2014-08-01

    The aim of this study is to compare the success rates of immediately placed and loaded NobelActive implants with the success rate of immediately placed implants that were allowed to osseointigrate prior to loading. The charts of all patients in a private oral surgery office receiving single-unit dental implants in the maxillary anterior region in fresh extraction sites from 2008-2011 were evaluated. All patients receiving NobelActive implants and immediate restorations were included in the study group, while those receiving implants with delayed restorations were included in the control group. Patient records were evaluated for variables such as age, gender, torque values at time of implant placement, smoking habits, use of bisphosphonates, and other significant diseases such as diabetes. The success rate of the study group was 92.9%, whereas the success rate of the control group was 97.6%. This was not statistically significant. Torque values of the failed implants of the study group were similar to those of successful implants in the study group. All implants placed in patients scheduled for immediate loading achieved high torque values and were able to be restored immediately. NobelActive implants were able to obtain high torque values for predictable immediate restoration in fresh extraction sites. Acceptable success rates with excellent soft tissue healing were achieved.

  15. A graphical simulator for active learning of MRI basics

    DEFF Research Database (Denmark)

    Wilhjelm, Jens E.; Duun-Henriksen, Jonas; Hanson, Lars G.

    2014-01-01

    This paper presents a MATLAB-based graphical user interface (GUI) for simulation of a simple magnetic resonance imaging (MRI) scanner that the student can operate and obtain results with. It is intended for the students in an introductory course in medical imaging and provides the students...

  16. Simulation Study on Active Noise Control for a 4 Tesla MRI Scanner

    Science.gov (United States)

    Li, Mingfeng; Lim, Teik C.; Lee, Jing-Huei

    2008-01-01

    The purpose of this work is to study computationally the possibility of the application of a hybrid active noise control technique for MRI acoustic noise reduction. A hybrid control system combined with both feedforward and feedback loops embedded is proposed for potential application on active MRI noise reduction. A set of computational simulation studies were performed. Sets of MRI acoustic noise emissions measured at the patient's left ear location were recorded and used in the simulation study. By comparing three different control systems, namely the feedback, the feedforward and the hybrid control, our results revealed that the hybrid control system is the most effective. The hybrid control system achieved approximately a 20 dB reduction at the principal frequency component. We concluded that the proposed hybrid active control scheme could have a potential application for MRI scanner noise reduction. PMID:18060719

  17. Simulation study on active noise control for a 4-T MRI scanner.

    Science.gov (United States)

    Li, Mingfeng; Lim, Teik C; Lee, Jing-Huei

    2008-04-01

    The purpose of this work is to study computationally the possibility of the application of a hybrid active noise control technique for magnetic resonance imaging (MRI) acoustic noise reduction. A hybrid control system combined with both feedforward and feedback loops embedded is proposed for potential application on active MRI noise reduction. A set of computational simulation studies were performed. Sets of MRI acoustic noise emissions measured at the patient's left ear location were recorded and used in the simulation study. By comparing three different control systems, namely, the feedback, the feedforward and the hybrid control, our results revealed that the hybrid control system is the most effective. The hybrid control system achieved approximately a 20-dB reduction at the principal frequency component. We concluded that the proposed hybrid active control scheme could have a potential application for MRI scanner noise reduction.

  18. Carbamazepine reduces memory induced activation of mesial temporal lobe structures: a pharmacological fMRI-study

    Directory of Open Access Journals (Sweden)

    Okujava Michael

    2001-11-01

    Full Text Available Abstract Background and Purpose It is not known whether carbamazepine (CBZ; a drug widely used in neurology and psychiatry influences the blood oxygenation level dependent (BOLD contrast changes induced by neuronal activation and measured by functional MRI (fMRI. We aimed to investigate the influence of CBZ on memory induced activation of the mesial temporal lobes in patients with symptomatic temporal lobe epilepsy (TLE. Material and Methods Twenty-one individual patients with refractory symptomatic TLE with different CBZ serum levels and 20 healthy controls were studied using BOLD fMRI. Mesial temporal lobe (MTL activation was induced by a task that is based on the retrieval of individually familiar visuo-spatial knowledge. The extent of significant MTL fMRI activation was measured and correlated with the CBZ serum level. Results In TLE patients, the extent of significant fMRI activation over both MTL was negatively correlated to the CBZ serum level (Spearman r = -0.654, P Conclusions In TLE patients, carbamazepine reduces the fMRI-detectable changes within the mesial temporal lobes as induced by effortful memory retrieval. FMRI appears to be suitable to study the effects of chronic drug treatment in patients with epilepsy.

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

    Energy Technology Data Exchange (ETDEWEB)

    Lim, T; Wang, J; Frank, S; Stafford, R; Bruno, T; Bathala, T; Mahmood, U; Pugh, T; Ibbott, G; Kudchadker, R [UT MD Anderson Cancer Center, Houston, TX (United States)

    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

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

    Directory of Open Access Journals (Sweden)

    Ralf Joukhadar

    2015-01-01

    Full Text Available 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.

  1. MRI of the Chest

    Medline Plus

    Full Text Available ... field of the MRI unit, metal and electronic items are not allowed in the exam room. In addition to affecting the MRI images, ... damaged pins, hairpins, metal zippers and similar metallic items, which can distort ... In most cases, an MRI exam is safe for patients with metal implants, except ...

  2. Lattice location and optical activation of rare earth implanted GaN

    CERN Document Server

    Wahl, U; Lorenz, K; Correia, J G; Monteiro, T; De Vries, B; Vantomme, A; Vianden, R

    2003-01-01

    This paper reviews the current knowledge on rare earths (REs) implanted into GaN with a special focus on their lattice location and on the optical activation by means of thermal annealing. While emission channeling experiments have given information on the lattice location of rare earths following low-dose (around 10$^{13}$ cm$^{-2}$) implantation, both in the as-implanted state and after annealing up to 900°C, the lattice location of higher-dose implants (10$^{14}-10^{15}$ cm$^{-2}$) and their defect annealing behaviour were studied using the Rutherford backscattering/channeling method. The available channeling and luminescence results suggest that the optical activation of implanted REs in GaN is related to their incorporation in substitutional Ga sites combined with the effective removal of the implantation damage.

  3. Active-passive gradient shielding for MRI acoustic noise reduction.

    Science.gov (United States)

    Edelstein, William A; Kidane, Tesfaye K; Taracila, Victor; Baig, Tanvir N; Eagan, Timothy P; Cheng, Yu-Chung N; Brown, Robert W; Mallick, John A

    2005-05-01

    An important source of MRI acoustic noise-magnet cryostat warm-bore vibrations caused by eddy-current-induced forces-can be mitigated by a passive metal shield mounted on the outside of a vibration-isolated, vacuum-enclosed shielded gradient set. Finite-element (FE) calculations for a z-gradient indicate that a 2-mm-thick Cu layer wrapped on the gradient assembly can decrease mechanical power deposition in the warm bore and reduce warm-bore acoustic noise production by about 25 dB. Eliminating the conducting warm bore and other magnet parts as significant acoustic noise sources could lead to the development of truly quiet, fully functioning MRI systems with noise levels below 70 dB.

  4. Functional brain activation differences in stuttering identified with a rapid fMRI sequence

    Science.gov (United States)

    Kraft, Shelly Jo; Choo, Ai Leen; Sharma, Harish; Ambrose, Nicoline G.

    2011-01-01

    The purpose of this study was to investigate whether brain activity related to the presence of stuttering can be identified with rapid functional MRI (fMRI) sequences that involved overt and covert speech processing tasks. The long-term goal is to develop sensitive fMRI approaches with developmentally appropriate tasks to identify deviant speech motor and auditory brain activity in children who stutter closer to the age at which recovery from stuttering is documented. Rapid sequences may be preferred for individuals or populations who do not tolerate long scanning sessions. In this report, we document the application of a picture naming and phoneme monitoring task in three minute fMRI sequences with adults who stutter (AWS). If relevant brain differences are found in AWS with these approaches that conform to previous reports, then these approaches can be extended to younger populations. Pairwise contrasts of brain BOLD activity between AWS and normally fluent adults indicated the AWS showed higher BOLD activity in the right inferior frontal gyrus (IFG), right temporal lobe and sensorimotor cortices during picture naming and and higher activity in the right IFG during phoneme monitoring. The right lateralized pattern of BOLD activity together with higher activity in sensorimotor cortices is consistent with previous reports, which indicates rapid fMRI sequences can be considered for investigating stuttering in younger participants. PMID:22133409

  5. Micro- to Macroroughness of Additively Manufactured Titanium Implants in Terms of Coagulation and Contact Activation.

    Science.gov (United States)

    Klingvall Ek, Rebecca; Hong, Jaan; Thor, Andreas; Bäckström, Mikael; Rännar, Lars-Erik

    This study aimed to evaluate how as-built electron beam melting (EBM) surface properties affect the onset of blood coagulation. The properties of EBM-manufactured implant surfaces for placement have, until now, remained largely unexplored in literature. Implants with conventional designs and custom-made implants have been manufactured using EBM technology and later placed into the human body. Many of the conventional implants used today, such as dental implants, display modified surfaces to optimize bone ingrowth, whereas custom-made implants, by and large, have machined surfaces. However, titanium in itself demonstrates good material properties for the purpose of bone ingrowth. Specimens manufactured using EBM were selected according to their surface roughness and process parameters. EBM-produced specimens, conventional machined titanium surfaces, as well as PVC surfaces for control were evaluated using the slide chamber model. A significant increase in activation was found, in all factors evaluated, between the machined samples and EBM-manufactured samples. The results show that EBM-manufactured implants with as-built surfaces augment the thrombogenic properties. EBM that uses Ti6Al4V powder appears to be a good manufacturing solution for load-bearing implants with bone anchorage. The as-built surfaces can be used "as is" for direct bone contact, although any surface treatment available for conventional implants can be performed on EBM-manufactured implants with a conventional design.

  6. Effects of motor fatigue on human brain activity, an fMRI study

    NARCIS (Netherlands)

    van Duinen, Hiske; Renken, Remco; Maurits, Natasha; Zijdewind, Inge

    2007-01-01

    The main purpose of this study was to investigate effects of motor fatigue on brain activation in humans, using fMRI. First, we assessed brain activation that correlated with muscle activity during brief contractions at different force levels (force modulation). Second, a similar analysis was done f

  7. Assessment of activated porous granules on implant fixation and early bone formation in sheep

    Directory of Open Access Journals (Sweden)

    Ming Ding

    2016-04-01

    Conclusion: In conclusion, despite nice bone formation and implant fixation in all groups, bioreactor activated graft material did not convincingly induce early implant fixation similar to allograft, and neither bioreactor nor by adding BMA credited additional benefit for bone formation in this model.

  8. Quantitative MRI reveals decelerated fatty infiltration in muscles of active FSHD patients.

    Science.gov (United States)

    Janssen, Barbara; Voet, Nicoline; Geurts, Alexander; van Engelen, Baziel; Heerschap, Arend

    2016-05-03

    To investigate the effects of aerobic exercise training (AET) and cognitive-behavioral therapy (CBT), directed towards an increase in daily physical activity, on the progression of fatty infiltration and edema in skeletal muscles of patients with facioscapulohumeral muscular dystrophy (FSHD) type 1 by T2 MRI. Quantitative T2 MRI (qT2 MRI) and fat-suppressed T2 MRI of the thigh were performed at 3T on 31 patients, 13 of whom received usual care (UC), 9 AET, and 9 CBT. Muscle-specific fat fractions (%), derived from qT2 MRI, were recorded pretreatment and posttreatment. Intervention effects were analyzed by comparing fat fraction progression rates of the UC with the treated groups using Mann-Whitney tests, and intermuscle differences by a linear mixed model. Edematous hyperintense lesions were identified on the fat-suppressed T2 MRI. The intraclass correlation coefficient for reproducibility of qT2 MRI fat assessment was 0.99. In the UC group, the fat fraction increased by 6.7/year (95% confidence interval [CI] 4.3 to 9.1). This rate decreased to 2.9/year (95% CI 0.7 to 5.2) in the AET (p = 0.03) and 1.7/year (95% CI -0.2 to 3.6) in the CBT group (p = 0.00015). The treatment effect differed among individual muscles. Fewer new edematous lesions occurred after therapy. Fat fraction derived from qT2 MRI is a reproducible and sensitive biomarker to monitor the effects of increased physical activity in individual muscles. This biomarker reports a favorable effect of AET and CBT on the rate of muscular deterioration in FSHD as reflected in decelerated fat replacement. This study provides Class II evidence that for patients with FSHD type 1, both AET and CBT decrease the rate of fatty infiltration in muscles. © 2016 American Academy of Neurology.

  9. Cost Analysis of MRI Services in Iran: An Application of Activity Based Costing Technique

    Directory of Open Access Journals (Sweden)

    Bayati

    2015-09-01

    Full Text Available Background Considerable development of MRI technology in diagnostic imaging, high cost of MRI technology and controversial issues concerning official charges (tariffs have been the main motivations to define and implement this study. Objectives The present study aimed to calculate the unit-cost of MRI services using activity-based costing (ABC as a modern cost accounting system and to fairly compare calculated unit-costs with official charges (tariffs. Materials and Methods We included both direct and indirect costs of MRI services delivered in fiscal year 2011 in Shiraz Shahid Faghihi hospital. Direct allocation method was used for distribution of overhead costs. We used micro-costing approach to calculate unit-cost of all different MRI services. Clinical cost data were retrieved from the hospital registering system. Straight-line method was used for depreciation cost estimation. To cope with uncertainty and to increase the robustness of study results, unit costs of 33 MRI services was calculated in terms of two scenarios. Results Total annual cost of MRI activity center (AC was calculated at USD 400,746 and USD 532,104 based on first and second scenarios, respectively. Ten percent of the total cost was allocated from supportive departments. The annual variable costs of MRI center were calculated at USD 295,904. Capital costs measured at USD 104,842 and USD 236, 200 resulted from the first and second scenario, respectively. Existing tariffs for more than half of MRI services were above the calculated costs. Conclusion As a public hospital, there are considerable limitations in both financial and administrative databases of Shahid Faghihi hospital. Labor cost has the greatest share of total annual cost of Shahid Faghihi hospital. The gap between unit costs and tariffs implies that the claim for extra budget from health providers may not be relevant for all services delivered by the studied MRI center. With some adjustments, ABC could be

  10. Cost Analysis of MRI Services in Iran: An Application of Activity Based Costing Technique.

    Science.gov (United States)

    Bayati, Mohsen; Mahboub Ahari, Alireza; Badakhshan, Abbas; Gholipour, Mahin; Joulaei, Hassan

    2015-10-01

    Considerable development of MRI technology in diagnostic imaging, high cost of MRI technology and controversial issues concerning official charges (tariffs) have been the main motivations to define and implement this study. The present study aimed to calculate the unit-cost of MRI services using activity-based costing (ABC) as a modern cost accounting system and to fairly compare calculated unit-costs with official charges (tariffs). We included both direct and indirect costs of MRI services delivered in fiscal year 2011 in Shiraz Shahid Faghihi hospital. Direct allocation method was used for distribution of overhead costs. We used micro-costing approach to calculate unit-cost of all different MRI services. Clinical cost data were retrieved from the hospital registering system. Straight-line method was used for depreciation cost estimation. To cope with uncertainty and to increase the robustness of study results, unit costs of 33 MRI services was calculated in terms of two scenarios. Total annual cost of MRI activity center (AC) was calculated at USD 400,746 and USD 532,104 based on first and second scenarios, respectively. Ten percent of the total cost was allocated from supportive departments. The annual variable costs of MRI center were calculated at USD 295,904. Capital costs measured at USD 104,842 and USD 236, 200 resulted from the first and second scenario, respectively. Existing tariffs for more than half of MRI services were above the calculated costs. As a public hospital, there are considerable limitations in both financial and administrative databases of Shahid Faghihi hospital. Labor cost has the greatest share of total annual cost of Shahid Faghihi hospital. The gap between unit costs and tariffs implies that the claim for extra budget from health providers may not be relevant for all services delivered by the studied MRI center. With some adjustments, ABC could be implemented in MRI centers. With the settlement of a reliable cost accounting system

  11. Unexpected global impact of VTA dopamine neuron activation as measured by opto-fMRI

    Science.gov (United States)

    Lohani, Sweyta; Poplawsky, Alexander John; Kim, Seong-Gi; Moghaddam, Bita

    2016-01-01

    Dopamine neurons in the ventral tegmental area (VTA) are strongly implicated in cognitive and affective processing as well as in psychiatric disorders including schizophrenia, ADHD and substance abuse disorders. In human studies, dopamine-related functions are routinely assessed using functional magnetic resonance imaging (fMRI) measures of blood oxygenation-level dependent (BOLD) signals during the performance of dopamine-dependent tasks. There is, however, a critical void in our knowledge about if and how activation of VTA dopamine neurons specifically influences regional or global fMRI signals. Here we used optogenetics in Th::Cre rats to selectively stimulate VTA dopamine neurons while simultaneously measuring global hemodynamic changes using BOLD and cerebral blood volume-weighted (CBVw) fMRI. Phasic activation of VTA dopamine neurons increased BOLD and CBVw fMRI signals in VTA-innervated limbic regions, including the ventral striatum (nucleus accumbens). Surprisingly, basal ganglia regions that receive sparse or no VTA dopaminergic innervation, including the dorsal striatum and the globus pallidus, were also activated. In fact, the most prominent fMRI signal increase in the forebrain was observed in the dorsal striatum that is not traditionally associated with VTA dopamine neurotransmission. These data establish causation between phasic activation of VTA dopamine neurons and global fMRI signals. They further suggest that mesolimbic and non-limbic basal ganglia dopamine circuits are functionally connected and, thus, provide a potential novel framework for understanding dopamine-dependent functions and interpreting data obtained from human fMRI studies. PMID:27457809

  12. Unexpected global impact of VTA dopamine neuron activation as measured by opto-fMRI.

    Science.gov (United States)

    Lohani, S; Poplawsky, A J; Kim, S-G; Moghaddam, B

    2017-04-01

    Dopamine neurons in the ventral tegmental area (VTA) are strongly implicated in cognitive and affective processing as well as in psychiatric disorders, including schizophrenia, depression, attention-deficit hyperactivity disorder and substance abuse disorders. In human studies, dopamine-related functions are routinely assessed using functional magnetic resonance imaging (fMRI) measures of blood oxygenation-level-dependent (BOLD) signals during the performance of dopamine-dependent tasks. There is, however, a critical void in our knowledge about whether and how activation of VTA dopamine neurons specifically influences regional or global fMRI signals. Here, we used optogenetics in Th::Cre rats to selectively stimulate VTA dopamine neurons while simultaneously measuring global hemodynamic changes using BOLD and cerebral blood volume-weighted (CBVw) fMRI. Phasic activation of VTA dopamine neurons increased BOLD and CBVw fMRI signals in VTA-innervated limbic regions, including the ventral striatum (nucleus accumbens). Surprisingly, basal ganglia regions that receive sparse or no VTA dopaminergic innervation, including the dorsal striatum and the globus pallidus, were also activated. In fact, the most prominent fMRI signal increase in the forebrain was observed in the dorsal striatum that is not traditionally associated with VTA dopamine neurotransmission. These data establish causation between phasic activation of VTA dopamine neurons and global fMRI signals. They further suggest that mesolimbic and non-limbic basal ganglia dopamine circuits are functionally connected and thus provide a potential novel framework for understanding dopamine-dependent functions and interpreting data obtained from human fMRI studies.

  13. Does functional MRI detect activation in white matter?A review of emerging evidence, issues, and future directions

    Directory of Open Access Journals (Sweden)

    Jodie Reanna Gawryluk

    2014-08-01

    Full Text Available Functional magnetic resonance imaging (fMRI is a non-invasive technique that allows for visualization of activated brain regions. Until recently, fMRI studies have focused on gray matter. There are two main reasons white matter fMRI remains controversial: 1 the blood oxygen level dependent (BOLD fMRI signal depends on cerebral blood flow and volume, which are lower in white matter than gray matter and 2 fMRI signal has been associated with post-synaptic potentials (mainly localized in gray matter as opposed to action potentials (the primary type of neural activity in white matter. Despite these observations, there is no direct evidence against measuring fMRI activation in white matter and reports of fMRI activation in white matter continue to increase. The questions underlying white matter fMRI activation are important. White matter fMRI activation has the potential to greatly expand the breadth of brain connectivity research, as well as improve the assessment and diagnosis of white matter and connectivity disorders. The current review provides an overview of the motivation to investigate white matter fMRI activation, as well as the published evidence of this phenomenon. We speculate on possible neurophysiologic bases of white matter fMRI signals, and discuss potential explanations for why reports of white matter fMRI activation are relatively scarce. We end with a discussion of future basic and clinical research directions in the study of white matter fMRI.

  14. Efficacy of ultrasound elastography in detecting active myositis in children: can it replace MRI?

    Energy Technology Data Exchange (ETDEWEB)

    Berko, Netanel S.; Levin, Terry L. [Montefiore Medical Center, Department of Radiology, Bronx, NY (United States); Hay, Arielle [Montefiore Medical Center, Department of Pediatrics, Division of Pediatric Rheumatology, Bronx, NY (United States); Miami Children' s Hospital, Department of Pediatrics, Miami, FL (United States); Sterba, Yonit; Wahezi, Dawn [Montefiore Medical Center, Department of Pediatrics, Division of Pediatric Rheumatology, Bronx, NY (United States)

    2015-09-15

    Juvenile idiopathic inflammatory myopathy is a rare yet potentially debilitating condition. MRI is used both for diagnosis and to assess response to treatment. No study has evaluated the performance of US elastography in the diagnosis of this condition in children. To assess the performance of compression-strain US elastography in detecting active myositis in children with clinically confirmed juvenile idiopathic inflammatory myopathy and to compare its efficacy to MRI. Children with juvenile idiopathic inflammatory myopathy underwent non-contrast MR imaging as well as compression-strain US elastography of the quadriceps muscles. Imaging findings from both modalities were compared to each other as well as to the clinical determination of active disease based on physical examination and laboratory data. Active myositis on MR was defined as increased muscle signal on T2-weighted images. Elastography images were defined as normal or abnormal based on a previously published numerical scale of muscle elastography in normal children. Muscle echogenicity was graded as normal or abnormal based on gray-scale sonographic images. Twenty-one studies were conducted in 18 pediatric patients (15 female, 3 male; age range 3-19 years). Active myositis was present on MRI in ten cases. There was a significant association between abnormal MRI and clinically active disease (P = 0.012). US elastography was abnormal in 4 of 10 cases with abnormal MRI and in 4 of 11 cases with normal MRI. There was no association between abnormal elastography and either MRI (P > 0.999) or clinically active disease (P > 0.999). Muscle echogenicity was normal in 11 patients; all 11 had normal elastography. Of the ten patients with increased muscle echogenicity, eight had abnormal elastography. There was a significant association between muscle echogenicity and US elastography (P < 0.001). The positive and negative predictive values for elastography in the determination of active myositis were 75% and 31

  15. Pectus excavatum with delayed diagnosis of implant tear on MRI apparently causing recurrent postoperative seromas: A case report

    Energy Technology Data Exchange (ETDEWEB)

    Iyer, Arti R.; Powell, Daniel K.; Irish, Robert D.; Math, Kevin R. [Mount Sinai Beth Israel Medical Center, Department of Radiology, New York, NY (United States)

    2015-08-15

    Seroma formation is the most common early postoperative complication after pectus excavatum repair, but later seromas are rare. While many seromas eventually resorb or decrease in size after aspiration, our case demonstrates recurrent seroma formation as a late complication of pectus excavatum repair in a patient with an implant tear. Postoperative seromas can result in prolonged chest wall pain, large chest wall masses, and increased mass effect on the heart with potential risk for resultant right ventricular outflow obstruction. This case report illustrates a solid silicone implant tear. Though rare, early recognition may help to decrease the likelihood of recurrent postoperative seromas. (orig.)

  16. EFFECTS OF COPPER ION IMPLANTATION ON ANTIBACTERIAL ACTIVITY OF AISI420 STAINLESS STEEL

    Institute of Scientific and Technical Information of China (English)

    Z.G. Dan; H.W. Ni; B.F. Xu; J. Xiong; P. Y. Xiong

    2005-01-01

    Antibacterial activity of AISI420 stainless steel (SS) implanted by copper was investigated. Ions extracted from a metal vapor vacuum arc (MEVVA) are sourced with 100keV energy and a dose range from 0.2×1017 to 2.0×1017ions .cm-2. The saturation dose of Cu implantation in AISI420 SS and Cu surface concentration were calculated at the energy of 100keV. The effect of dose on the antibacterial activity was analyzed. Results of antibacterial test show that the saturation dose is the optimum implantation dose for best antibacterial activity, which is above 99% against both Escherichia coli and Staphylococcus aureus. Novel phases such as Fe4Cu3 and Cu9.9Fe0.1 were found in the implanted layer by glancing angle X-ray diffraction (GXRD). The antibacterial activity of AISI420 SS attributes to Cu-contained phase.

  17. Auditory cortical activity during cochlear implant-mediated perception of spoken language, melody, and rhythm.

    Science.gov (United States)

    Limb, Charles J; Molloy, Anne T; Jiradejvong, Patpong; Braun, Allen R

    2010-03-01

    Despite the significant advances in language perception for cochlear implant (CI) recipients, music perception continues to be a major challenge for implant-mediated listening. Our understanding of the neural mechanisms that underlie successful implant listening remains limited. To our knowledge, this study represents the first neuroimaging investigation of music perception in CI users, with the hypothesis that CI subjects would demonstrate greater auditory cortical activation than normal hearing controls. H(2) (15)O positron emission tomography (PET) was used here to assess auditory cortical activation patterns in ten postlingually deafened CI patients and ten normal hearing control subjects. Subjects were presented with language, melody, and rhythm tasks during scanning. Our results show significant auditory cortical activation in implant subjects in comparison to control subjects for language, melody, and rhythm. The greatest activity in CI users compared to controls was seen for language tasks, which is thought to reflect both implant and neural specializations for language processing. For musical stimuli, PET scanning revealed significantly greater activation during rhythm perception in CI subjects (compared to control subjects), and the least activation during melody perception, which was the most difficult task for CI users. These results may suggest a possible relationship between auditory performance and degree of auditory cortical activation in implant recipients that deserves further study.

  18. MRI changes and complement activation correlate with epileptogenicity in a mouse model of temporal lobe epilepsy.

    Science.gov (United States)

    Kharatishvili, Irina; Shan, Zuyao Y; She, David T; Foong, Samuel; Kurniawan, Nyoman D; Reutens, David C

    2014-03-01

    The complex pathogenesis of temporal lobe epilepsy includes neuronal and glial pathology, synaptic reorganization, and an immune response. However, the spatio-temporal pattern of structural changes in the brain that provide a substrate for seizure generation and modulate the seizure phenotype is yet to be completely elucidated. We used quantitative magnetic resonance imaging (MRI) to study structural changes triggered by status epilepticus (SE) and their association with epileptogenesis and with activation of complement component 3 (C3). SE was induced by injection of pilocarpine in CD1 mice. Quantitative diffusion-weighted imaging and T2 relaxometry was performed using a 16.4-Tesla MRI scanner at 3 h and 1, 2, 7, 14, 28, 35, and 49 days post-SE. Following longitudinal MRI examinations, spontaneous recurrent seizures and interictal spikes were quantified using continuous video-EEG monitoring. Immunohistochemical analysis of C3 expression was performed at 48 h, 7 days, and 4 months post-SE. MRI changes were dynamic, reflecting different outcomes in relation to the development of epilepsy. Apparent diffusion coefficient changes in the hippocampus at 7 days post-SE correlated with the severity of the evolving epilepsy. C3 activation was found in all stages of epileptogenesis within the areas with significant MRI changes and correlated with the severity of epileptic condition.

  19. MRI of the Chest

    Medline Plus

    Full Text Available ... You may resume your usual activities and normal diet immediately after the exam. On very rare occasions, ... Magnetic Resonance Imaging (MRI) Safety MRI Safety During Pregnancy Images related to Magnetic Resonance Imaging (MRI) - Chest ...

  20. Delayed gadolinium-enhanced MRI of cartilage and T2 mapping for evaluation of reparative cartilage-like tissue after autologous chondrocyte implantation associated with Atelocollagen-based scaffold in the knee

    Energy Technology Data Exchange (ETDEWEB)

    Tadenuma, Taku; Uchio, Yuji; Kumahashi, Nobuyuki; Iwasa, Junji [Shimane University School of Medicine, Department of Orthopaedic Surgery, Izumo-shi, Shimane-ken (Japan); Fukuba, Eiji; Kitagaki, Hajime [Shimane University School of Medicine, Department of Radiology, Izumo-shi, Shimane-ken (Japan); Ochi, Mitsuo [Hiroshima University, Department of Orthopaedic Surgery, Integrated Health Sciences, Institute of Biomedical and Health Sciences, Minami-ku, Hiroshima (Japan)

    2016-10-15

    To elucidate the quality of tissue-engineered cartilage after an autologous chondrocyte implantation (ACI) technique with Atelocollagen gel as a scaffold in the knee in the short- to midterm postoperatively, we assessed delayed gadolinium-enhanced magnetic resonance imaging (MRI) of cartilage (dGEMRIC) and T2 mapping and clarified the relationship between T1 and T2 values and clinical results. In this cross-sectional study, T1 and T2 mapping were performed on 11 knees of 8 patients (mean age at ACI, 37.2 years) with a 3.0-T MRI scanner. T1{sub implant} and T2{sub implant} values were compared with those of the control cartilage region (T1{sub control} and T2{sub control}). Lysholm scores were also assessed for clinical evaluation. The relationships between the T1 and T2 values and the clinical Lysholm score were also assessed. There were no significant differences in the T1 values between the T1{sub implant} (386.64 ± 101.78 ms) and T1{sub control} (375.82 ± 62.89 ms) at the final follow-up. The implants showed significantly longer T2 values compared to the control cartilage (53.83 ± 13.89 vs. 38.21 ± 4.43 ms). The postoperative Lysholm scores were significantly higher than the preoperative scores. A significant correlation was observed between T1{sub implant} and clinical outcomes, but not between T2{sub implant} and clinical outcomes. Third-generation ACI implants might have obtained an almost equivalent glycosaminoglycan concentration compared to the normal cartilage, but they had lower collagen density at least 3 years after transplantation. The T1{sub implant} value, but not the T2 value, might be a predictor of clinical outcome after ACI. (orig.)

  1. Enhancing motor network activity using real-time functional MRI neurofeedback of left premotor cortex

    Directory of Open Access Journals (Sweden)

    Theo Ferreira Marins

    2015-12-01

    Full Text Available Neurofeedback by functional Magnetic Resonance Imaging (fMRI is a technique of potential therapeutic relevance that allows individuals to be aware of their own neurophysiological responses and to voluntarily modulate the activity of specific brain regions, such as the premotor cortex (PMC, important for motor recovery after brain injury. We investigated (i whether healthy human volunteers are able to up-regulate the activity of the left PMC during a right hand finger tapping motor imagery (MI task while receiving continuous fMRI-neurofeedback, and (ii whether successful modulation of brain activity influenced non-targeted motor control regions. During the MI task, participants of the neurofeedback group (NFB received ongoing visual feedback representing the level of fMRI responses within their left PMC. Control (CTL group participants were shown similar visual stimuli, but these were non-contingent on brain activity. Both groups showed equivalent levels of behavioral ratings on arousal and motor imagery, before and during the fMRI protocol. In the NFB, but not in CLT group, brain activation during the last run compared to the first run revealed increased activation in the left PMC. In addition, the NFB group showed increased activation in motor control regions extending beyond the left PMC target area, including the supplementary motor area, basal ganglia and cerebellum. Moreover, in the last run, the NFB group showed stronger activation in the left PMC/inferior frontal gyrus when compared to the CTL group. Our results indicate that modulation of PMC and associated motor control areas can be achieved during a single neurofeedback-fMRI session. These results contribute to a better understanding of the underlying mechanisms of MI-based neurofeedback training, with direct implications for rehabilitation strategies in severe brain disorders, such as stroke.

  2. Value of whole body MRI and dynamic contrast enhanced MRI in the diagnosis, follow-up and evaluation of disease activity and extent in multiple myeloma

    Energy Technology Data Exchange (ETDEWEB)

    Dutoit, Julie C., E-mail: Julie.Dutoit@UGent.be; Vanderkerken, Matthias A., E-mail: Matthias.Vanderkerken@UGent.be; Verstraete, Koenraad L., E-mail: Koenraad.Verstraete@UGent.be

    2013-09-15

    Purpose: To evaluate the significance of dynamic contrast enhanced MRI (DCE-MRI) and whole body MRI (WB-MRI) in the diagnosis, prognosis and assessment of therapy for patients with monoclonal gammopathy of undetermined significance (MGUS) and multiple myeloma (MM). Materials and methods: The retrospective study includes 219 patients providing 463 WB-MRI and DCE-MRI investigations for the subgroups MGUS (n = 70), MM active disease (n = 126; this includes 70 patients with new diagnosis of MM, according to the International Staging System (ISS): 41.4% ISS stage I, 20.0% ISS stage II, 7.1% ISS stage III, 31.4% insufficient for staging; and 56 patients with ‘(re-)active disease’: 16.07% relapse, 32.14% progressive disease and 51.79% stable disease) and MM remission (n = 23; 60.87% complete remission, 17.39% very good partial remission and 21.74% partial remission). Investigations of patients with hereditary multiple exostoses (n = 5), neurofibromatosis (n = 7) and healthy persons (n = 9) were added as control subjects (n = 21). WB-MRI evaluation was done by evaluating thirteen skeletal regions, providing a ‘skeletal score’. DCE-MRI images of the spine, were analyzed with regions-of-interest and time-intensity-curves (TIC). Results: All TIC parameters can significantly differentiate between the predefined subgroups (p < 0.001). One hundred days after autologous stem cell transplantation a 75% decrease of the slope wash-in value (p < 0.001) can be seen. A cubic regression trend between ‘skeletal score’ and slope wash-in (adj.R{sup 2} = 0.412) could demonstrate a significant increase bone marrow perfusion if MM affects more than 10 skeletal regions (p < 0.001), associated with a poorer prognosis (p < 0.001). Conclusion: DCE-MRI evaluation of the spine is useful for diagnosis of MM, follow-up after stem cell transplantation and evaluation of disease activity. A combined evaluation with WB-MRI and DCE-MRI provides additional micro-vascular information on the

  3. Microstimulation at the bone-implant interface upregulates osteoclast activation pathways.

    Science.gov (United States)

    Stadelmann, Vincent A; Terrier, Alexandre; Pioletti, Dominique P

    2008-02-01

    Peri-implant bone resorption after total joint arthroplasty is a key parameter in aseptic loosening. Implant wear debris and biomechanical aspects have both been demonstrated to be part of the bone resorption process. However, neither of these two parameters has been clearly identified as the primary initiator of peri-implant bone resorption. For the biomechanical parameters, micromotions were measured at the bone-implant interface during normal gait cycles. The amplitude of the micromotions was shown to trigger differentiation of bone tissues. So far no data exists directly quantifying the effect of micromotion and compression on human bone. We hypothesize that micromotion and compression at the bone-implant interface may induce direct activation of bone resorption around the implant through osteoblasts-osteoclasts cell signaling in human bone. This hypothesis was tested with an ex vivo loading system developed to stimulate trabecular bone cores and mimic the micromotions arising at the bone-implant interface. Gene expression of RANKL, OPG, TGFB2, IFNG and CSF-1 was analyzed after no mechanical stimulation (control), exposure to compression or exposure to micromotions. We observed an 8-fold upregulation of RANKL after exposure to micromotions, and downregulation of OPG, IFNG and TGFB2. The RANKL:OPG ratio was upregulated 24-fold after micromotions. This suggests that the micromotions arising at the bone-implant interface during normal gait cycles induce a bone resorption response after only 1 h, which occurs before any wear debris particles enter the system.

  4. Contrast-enhanced MRI compared with the physical examination in the evaluation of disease activity in juvenile idiopathic arthritis

    Energy Technology Data Exchange (ETDEWEB)

    Hemke, Robert; Maas, Mario [Academic Medical Centre, University of Amsterdam, Department of Radiology, Amsterdam (Netherlands); Veenendaal, Mira van; Kuijpers, Taco W. [University of Amsterdam, Department of Paediatric Haematology, Immunology, Rheumatology and Infectious Disease, Emma Children' s Hospital AMC, Amsterdam (Netherlands); Dolman, Koert M. [Department of Paediatric Rheumatology, Amsterdam (Netherlands); St. Lucas Andreas Hospital, Department of Paediatrics, Amsterdam (Netherlands); Rossum, Marion A.J. van; Berg, J.M. van den [University of Amsterdam, Department of Paediatric Haematology, Immunology, Rheumatology and Infectious Disease, Emma Children' s Hospital AMC, Amsterdam (Netherlands); Department of Paediatric Rheumatology, Amsterdam (Netherlands)

    2014-02-15

    To assess the value of magnetic resonance imaging (MRI) in discriminating between active and inactive juvenile idiopathic arthritis (JIA) patients and to compare physical examination outcomes with MRI outcomes in the assessment of disease status in JIA patients. Consecutive JIA patients with knee involvement were prospectively studied using an open-bore MRI. Imaging findings from 146 JIA patients were analysed (59.6 % female; mean age, 12.9 years). Patients were classified as clinically active or inactive. MRI features were evaluated using the JAMRIS system, comprising validated scores for synovial hypertrophy, bone marrow oedema, cartilage lesions and bone erosions. Inter-reader reliability was good for all MRI features (intra-class correlation coefficient [ICC] = 0.87-0.94). No differences were found between the two groups regarding MRI scores of bone marrow oedema, cartilage lesions or bone erosions. Synovial hypertrophy scores differed significantly between groups (P = 0.016). Nonetheless, synovial hypertrophy was also present in 14 JIA patients (35.9 %) with clinically inactive disease. Of JIA patients considered clinically active, 48.6 % showed no signs of MRI-based synovitis. MRI can discriminate between clinically active and inactive JIA patients. However, physical examination is neither very sensitive nor specific in evaluating JIA disease activity compared with MRI. Subclinical synovitis was present in >35 % of presumed clinically inactive patients. (orig.)

  5. MRI of the Chest

    Medline Plus

    Full Text Available ... it may cause some medical devices to malfunction. Most orthopedic implants pose no risk, but you should ... or if you have asthma. The contrast material most commonly used for an MRI exam contains a ...

  6. MRI of the Chest

    Medline Plus

    Full Text Available ... may cause some medical devices to malfunction. Most orthopedic implants pose no risk, but you should always ... metal objects. In general, metal objects used in orthopedic surgery pose no risk during MRI. However, a ...

  7. MRI of the Chest

    Medline Plus

    Full Text Available ... is not harmful, but it may cause some medical devices to malfunction. Most orthopedic implants pose no ... Chest? Magnetic resonance imaging (MRI) is a noninvasive medical test that physicians use to diagnose medical conditions. ...

  8. MRI of the Chest

    Medline Plus

    Full Text Available ... and should not enter the MRI scanning area: cochlear (ear) implant some types of clips used for ... follow-up exam is done because a potential abnormality needs further evaluation with additional views or a ...

  9. Detection of Sulfatase Enzyme Activity with a CatalyCEST MRI Contrast Agent.

    Science.gov (United States)

    Sinharay, Sanhita; Fernández-Cuervo, Gabriela; Acfalle, Jasmine P; Pagel, Mark D

    2016-05-01

    A chemical exchange saturation transfer (CEST) MRI contrast agent has been developed that detects sulfatase enzyme activity. The agent produces a CEST signal at δ=5.0 ppm before enzyme activity, and a second CEST signal appears at δ=9.0 ppm after the enzyme cleaves a sulfate group from the agent. The comparison of the two signals improved detection of sulfatase activity.

  10. Abnormal fMRI Activation Pattern during Story Listening in Individuals with Down Syndrome

    Science.gov (United States)

    Reynolds Losin, Elizabeth A.; Rivera, Susan M.; O'Hare, Elizabeth D.; Sowell, Elizabeth R.; Pinter, Joseph D.

    2009-01-01

    Down syndrome is characterized by disproportionately severe impairments of speech and language, yet little is known about the neural underpinnings of these deficits. We compared fMRI activation patterns during passive story listening in 9 young adults with Down syndrome and 9 approximately age-matched, typically developing controls. The typically…

  11. Simultaneous EMG-Functional MRI Recordings Can Directly Relate Hyperkinetic Movements to Brain Activity

    NARCIS (Netherlands)

    van Rootselaar, Anne-Fleur; Maurits, Natasha M.; Renken, Remco; Koelman, Johannes H. T. M.; Hoogduin, Johannes M.; Leenders, Klaus L.; Tijssen, Marina A. J.

    2008-01-01

    Objective: To apply and validate the use of electromyogram (EMG) recorded during functional magnetic resonance imaging (fMRI) in patients with movement disorders, to directly relate involuntary movements to brain activity. Methods: Eight "familial cortical myoclonic tremor with epilepsy" (FCMTE) pat

  12. Abnormal fMRI Activation Pattern during Story Listening in Individuals with Down Syndrome

    Science.gov (United States)

    Reynolds Losin, Elizabeth A.; Rivera, Susan M.; O'Hare, Elizabeth D.; Sowell, Elizabeth R.; Pinter, Joseph D.

    2009-01-01

    Down syndrome is characterized by disproportionately severe impairments of speech and language, yet little is known about the neural underpinnings of these deficits. We compared fMRI activation patterns during passive story listening in 9 young adults with Down syndrome and 9 approximately age-matched, typically developing controls. The typically…

  13. Segmentation of Brain Tumors in MRI Images Using Three-Dimensional Active Contour without Edge

    Directory of Open Access Journals (Sweden)

    Ali M. Hasan

    2016-11-01

    Full Text Available Brain tumor segmentation in magnetic resonance imaging (MRI is considered a complex procedure because of the variability of tumor shapes and the complexity of determining the tumor location, size, and texture. Manual tumor segmentation is a time-consuming task highly prone to human error. Hence, this study proposes an automated method that can identify tumor slices and segment the tumor across all image slices in volumetric MRI brain scans. First, a set of algorithms in the pre-processing stage is used to clean and standardize the collected data. A modified gray-level co-occurrence matrix and Analysis of Variance (ANOVA are employed for feature extraction and feature selection, respectively. A multi-layer perceptron neural network is adopted as a classifier, and a bounding 3D-box-based genetic algorithm is used to identify the location of pathological tissues in the MRI slices. Finally, the 3D active contour without edge is applied to segment the brain tumors in volumetric MRI scans. The experimental dataset consists of 165 patient images collected from the MRI Unit of Al-Kadhimiya Teaching Hospital in Iraq. Results of the tumor segmentation achieved an accuracy of 89% ± 4.7% compared with manual processes.

  14. Acute patellofemoral pain: aggravating activities, clinical examination, MRI and ultrasound findings

    DEFF Research Database (Denmark)

    Brushoj, C.; Holmich, P.; Nielsen, M.B.;

    2008-01-01

    Objective: To investigate acute anterior knee pain caused by overuse in terms of pain location, aggravating activities, findings on clinical examination and ultrasound/MRI examination. To determine if acute anterior knee pain caused by overuse should be classified as a subgroup of patellofemoral...... pain syndrome (PFPS). Methods: In a observational study design 30 army recruits with anterior knee pain (mean duration of pain 4 weeks) were examined using the PFPS pain severity scale (PSS), knee pain diagrams, standardised clinical examination, ultrasound and MRI examinations. Results: On PSS typical......%)), but other synovial covered structures including the fat pad of Hoffa (12 patients (40%)), the medial plica and the joint line (12 patients (40%)) were also involved. Only eight patients (27%) experienced pain on the patellofemoral compression test. Only discrete changes was detected on MRI...

  15. fMRI activation patterns in an analytic reasoning task: consistency with EEG source localization

    Science.gov (United States)

    Li, Bian; Vasanta, Kalyana C.; O'Boyle, Michael; Baker, Mary C.; Nutter, Brian; Mitra, Sunanda

    2010-03-01

    Functional magnetic resonance imaging (fMRI) is used to model brain activation patterns associated with various perceptual and cognitive processes as reflected by the hemodynamic (BOLD) response. While many sensory and motor tasks are associated with relatively simple activation patterns in localized regions, higher-order cognitive tasks may produce activity in many different brain areas involving complex neural circuitry. We applied a recently proposed probabilistic independent component analysis technique (PICA) to determine the true dimensionality of the fMRI data and used EEG localization to identify the common activated patterns (mapped as Brodmann areas) associated with a complex cognitive task like analytic reasoning. Our preliminary study suggests that a hybrid GLM/PICA analysis may reveal additional regions of activation (beyond simple GLM) that are consistent with electroencephalography (EEG) source localization patterns.

  16. N-methyl-D-aspartate receptor encephalitis mediates loss of intrinsic activity measured by functional MRI.

    Science.gov (United States)

    Brier, Matthew R; Day, Gregory S; Snyder, Abraham Z; Tanenbaum, Aaron B; Ances, Beau M

    2016-06-01

    Spontaneous brain activity is required for the development and maintenance of normal brain function. Many disease processes disrupt the organization of intrinsic brain activity, but few pervasively reduce the amplitude of resting state blood oxygen level dependent (BOLD) fMRI fluctuations. We report the case of a female with anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis, longitudinally studied during the course of her illness to determine the contribution of NMDAR signaling to spontaneous brain activity. Resting state BOLD fMRI was measured at the height of her illness and 18 weeks following discharge from hospital. Conventional resting state networks were defined using established methods. Correlation and covariance matrices were calculated by extracting the BOLD time series from regions of interest and calculating either the correlation or covariance quantity. The intrinsic activity was compared between visits, and to expected activity from 45 similarly aged healthy individuals. Near the height of the illness, the patient exhibited profound loss of consciousness, high-amplitude slowing of the electroencephalogram, and a severe reduction in the amplitude of spontaneous BOLD fMRI fluctuations. The patient's neurological status and measures of intrinsic activity improved following treatment. We conclude that NMDAR-mediated signaling plays a critical role in the mechanisms that give rise to organized spontaneous brain activity. Loss of intrinsic activity is associated with profound disruptions of consciousness and cognition.

  17. Electrical Activation Studies of Ion Implanted Gallium Nitride

    Science.gov (United States)

    2001-11-20

    Amplifier Electromagnet Controller Lakeshore DRC -91CA Temperature Controller 706 Scanner 196 Digital Multimeter 220 Current Source 617 Electrometer...complete list of publications resulting from this doctoral research. The list is divided into three sections: journal articles, refereed conference...2001. Refereed Conference Proceedings: “Optical Characterization of Mg- and Si-Implanted GaN,” Fellows J., Yeo Y.K., Hengehold R., and Krasnobaev

  18. Combining EEG Microstates with fMRI Structural Features for Modeling Brain Activity.

    Science.gov (United States)

    Michalopoulos, Kostas; Bourbakis, Nikolaos

    2015-12-01

    Combining information from Electroencephalography (EEG) and Functional Magnetic Resonance Imaging (fMRI) has been a topic of increased interest recently. The main advantage of the EEG is its high temporal resolution, in the scale of milliseconds, while the main advantage of fMRI is the detection of functional activity with good spatial resolution. The advantages of each modality seem to complement each other, providing better insight in the neuronal activity of the brain. The main goal of combining information from both modalities is to increase the spatial and the temporal localization of the underlying neuronal activity captured by each modality. This paper presents a novel technique based on the combination of these two modalities (EEG, fMRI) that allow a better representation and understanding of brain activities in time. EEG is modeled as a sequence of topographies, based on the notion of microstates. Hidden Markov Models (HMMs) were used to model the temporal evolution of the topography of the average Event Related Potential (ERP). For each model the Fisher score of the sequence is calculated by taking the gradient of the trained model parameters. The Fisher score describes how this sequence deviates from the learned HMM. Canonical Partial Least Squares (CPLS) were used to decompose the two datasets and fuse the EEG and fMRI features. In order to test the effectiveness of this method, the results of this methodology were compared with the results of CPLS using the average ERP signal of a single channel. The presented methodology was able to derive components that co-vary between EEG and fMRI and present significant differences between the two tasks.

  19. Relationship between saccadic eye movements and cortical activity as measured by fMRI

    DEFF Research Database (Denmark)

    Kimmig, H.; Greenlee, M.W.; Gondan, Matthias;

    2001-01-01

    quantitative changes in cortical activity associated with qualitative changes in the saccade task for comparable levels of saccadic activity. All experiments required the simultaneous acquisition of eye movement and fMRI data. For this purpose we used a new high-resolution limbus-tracking technique......We investigated the quantitative relationship between saccadic activity (as reflected in frequency of occurrence and amplitude of saccades) and blood oxygenation level dependent (BOLD) changes in the cerebral cortex using functional magnetic resonance imaging (fMRI). Furthermore, we investigated....... The latter finding is taken to indicate a more demanding cortical processing in the "anti" task than the "pro" task, which could explain the observed difference in BOLD activation. We hold that a quantitative analysis of saccade parameters (especially saccade frequency and latency) is important...

  20. Intersession reliability of fMRI activation for heat pain and motor tasks

    Directory of Open Access Journals (Sweden)

    Raimi L. Quiton

    2014-01-01

    Full Text Available As the practice of conducting longitudinal fMRI studies to assess mechanisms of pain-reducing interventions becomes more common, there is a great need to assess the test–retest reliability of the pain-related BOLD fMRI signal across repeated sessions. This study quantitatively evaluated the reliability of heat pain-related BOLD fMRI brain responses in healthy volunteers across 3 sessions conducted on separate days using two measures: (1 intraclass correlation coefficients (ICC calculated based on signal amplitude and (2 spatial overlap. The ICC analysis of pain-related BOLD fMRI responses showed fair-to-moderate intersession reliability in brain areas regarded as part of the cortical pain network. Areas with the highest intersession reliability based on the ICC analysis included the anterior midcingulate cortex, anterior insula, and second somatosensory cortex. Areas with the lowest intersession reliability based on the ICC analysis also showed low spatial reliability; these regions included pregenual anterior cingulate cortex, primary somatosensory cortex, and posterior insula. Thus, this study found regional differences in pain-related BOLD fMRI response reliability, which may provide useful information to guide longitudinal pain studies. A simple motor task (finger-thumb opposition was performed by the same subjects in the same sessions as the painful heat stimuli were delivered. Intersession reliability of fMRI activation in cortical motor areas was comparable to previously published findings for both spatial overlap and ICC measures, providing support for the validity of the analytical approach used to assess intersession reliability of pain-related fMRI activation. A secondary finding of this study is that the use of standard ICC alone as a measure of reliability may not be sufficient, as the underlying variance structure of an fMRI dataset can result in inappropriately high ICC values; a method to eliminate these false positive results

  1. Effects of calcium-modified titanium implant surfaces on platelet activation, clot formation, and osseointegration.

    Science.gov (United States)

    Anitua, Eduardo; Prado, Roberto; Orive, Gorka; Tejero, Ricardo

    2015-03-01

    The clinical success of load bearing dental and orthopedic implants relies on adequate osseointegration. Because of its favorable properties, titanium is generally considered as the material of choice. Following implant placement, titanium surfaces establish an ionic equilibrium with the surrounding tissues in which calcium plays major roles. Calcium is a cofactor of the coagulation cascade that mediates plasma protein adsorption and intervenes in a number of other intra and extracellular processes relevant for bone regeneration. In this study, titanium surfaces were modified with calcium ions (Ca(2+) surfaces) and their responses to in vitro and in vivo models were analyzed. Unlike unmodified surfaces, Ca(2+) surfaces were superhydrophilic and induced surface clot formation, platelet adsorption and activation when exposed to blood plasma. Interestingly, in vivo osseointegration using a peri-implant gap model in rabbit demonstrated that Ca(2+) surfaces significantly improved peri-implant bone volume and density at 2 weeks and bone implant contact at 8 weeks as compared to the unmodified controls. The combination of Ca(2+) surfaces with plasma rich in growth factors produced significantly more bone contact already at 2 weeks of implantation. These findings suggest the importance of the provisional matrix formation on tissue integration and highlight the clinical potential of Ca(2+) titanium surfaces as efficient stimulators of implant osseointegration.

  2. Dynamic Three-Dimensional Shoulder Mri during Active Motion for Investigation of Rotator Cuff Diseases.

    Directory of Open Access Journals (Sweden)

    Christine Tempelaere

    Full Text Available MRI is the standard methodology in diagnosis of rotator cuff diseases. However, many patients continue to have pain despite treatment, and MRI of a static unloaded shoulder seems insufficient for best diagnosis and treatment. This study evaluated if Dynamic MRI provides novel kinematic data that can be used to improve the understanding, diagnosis and best treatment of rotator cuff diseases.Dynamic MRI provided real-time 3D image series and was used to measure changes in the width of subacromial space, superior-inferior translation and anterior-posterior translation of the humeral head relative to the glenoid during active abduction. These measures were investigated for consistency with the rotator cuff diseases classifications from standard MRI.The study included: 4 shoulders with massive rotator cuff tears, 5 shoulders with an isolated full-thickness supraspinatus tear, 5 shoulders with tendinopathy and 6 normal shoulders. A change in the width of subacromial space greater than 4mm differentiated between rotator cuff diseases with tendon tears (massive cuff tears and supraspinatus tear and without tears (tendinopathy (p = 0.012. The range of the superior-inferior translation was higher in the massive cuff tears group (6.4mm than in normals (3.4mm (p = 0.02. The range of the anterior-posterior translation was higher in the massive cuff tears (9.2 mm and supraspinatus tear (9.3 mm shoulders compared to normals (3.5mm and tendinopathy (4.8mm shoulders (p = 0.05.The Dynamic MRI enabled a novel measure; 'Looseness', i.e. the translation of the humeral head on the glenoid during an abduction cycle. Looseness was better able at differentiating different forms of rotator cuff disease than a simple static measure of relative glenohumeral position.

  3. Dynamic Three-Dimensional Shoulder Mri during Active Motion for Investigation of Rotator Cuff Diseases

    Science.gov (United States)

    Tempelaere, Christine; Pierrart, Jérome; Lefèvre-Colau, Marie-Martine; Vuillemin, Valérie; Cuénod, Charles-André; Hansen, Ulrich; Mir, Olivier; Skalli, Wafa; Gregory, Thomas

    2016-01-01

    Background MRI is the standard methodology in diagnosis of rotator cuff diseases. However, many patients continue to have pain despite treatment, and MRI of a static unloaded shoulder seems insufficient for best diagnosis and treatment. This study evaluated if Dynamic MRI provides novel kinematic data that can be used to improve the understanding, diagnosis and best treatment of rotator cuff diseases. Methods Dynamic MRI provided real-time 3D image series and was used to measure changes in the width of subacromial space, superior-inferior translation and anterior-posterior translation of the humeral head relative to the glenoid during active abduction. These measures were investigated for consistency with the rotator cuff diseases classifications from standard MRI. Results The study included: 4 shoulders with massive rotator cuff tears, 5 shoulders with an isolated full-thickness supraspinatus tear, 5 shoulders with tendinopathy and 6 normal shoulders. A change in the width of subacromial space greater than 4mm differentiated between rotator cuff diseases with tendon tears (massive cuff tears and supraspinatus tear) and without tears (tendinopathy) (p = 0.012). The range of the superior-inferior translation was higher in the massive cuff tears group (6.4mm) than in normals (3.4mm) (p = 0.02). The range of the anterior-posterior translation was higher in the massive cuff tears (9.2 mm) and supraspinatus tear (9.3 mm) shoulders compared to normals (3.5mm) and tendinopathy (4.8mm) shoulders (p = 0.05). Conclusion The Dynamic MRI enabled a novel measure; ‘Looseness’, i.e. the translation of the humeral head on the glenoid during an abduction cycle. Looseness was better able at differentiating different forms of rotator cuff disease than a simple static measure of relative glenohumeral position. PMID:27434235

  4. MRI of the Chest

    Medline Plus

    Full Text Available ... metallic items, which can distort MRI images removable dental work pens, pocket knives and eyeglasses body piercings In most cases, an MRI exam is safe for patients with metal implants, except for a few types. People with the ...

  5. A living thick nanofibrous implant bifunctionalized with active growth factor and stem cells for bone regeneration

    Directory of Open Access Journals (Sweden)

    Eap S

    2015-02-01

    Full Text Available Sandy Eap,1,2,* Laetitia Keller,1–3,* Jessica Schiavi,1,2 Olivier Huck,1,2 Leandro Jacomine,4 Florence Fioretti,1,2 Christian Gauthier,4 Victor Sebastian,1,3,5 Pascale Schwinté,1,2 Nadia Benkirane-Jessel1,21INSERM, UMR 1109, Osteoarticular and Dental Regenerative Nanomedicine Laboratory, FMTS, Faculté de Médecine, Strasbourg, France; 2Faculté de Chirurgie Dentaire, Université de Strasbourg, Strasbourg, France; 3Department of Chemical Engineering, Aragon Nanoscience Institute, University of Zaragoza, Zaragoza, Spain; 4CNRS (National Center for Scientific Research, ICS (Charles Sadron Institute, Strasbourg, France; 5Networking Research Center of Bioengineering, Biomaterials and Nanomedicine, Zaragoza, Spain*These authors contributed equally to this workAbstract: New-generation implants focus on robust, durable, and rapid tissue regeneration to shorten recovery times and decrease risks of postoperative complications for patients. Herein, we describe a new-generation thick nanofibrous implant functionalized with active containers of growth factors and stem cells for regenerative nanomedicine. A thick electrospun poly(ε-caprolactone nanofibrous implant (from 700 µm to 1 cm thick was functionalized with chitosan and bone morphogenetic protein BMP-7 as growth factor using layer-by-layer technology, producing fish scale-like chitosan/BMP-7 nanoreservoirs. This extracellular matrix-mimicking scaffold enabled in vitro colonization and bone regeneration by human primary osteoblasts, as shown by expression of osteocalcin, osteopontin, and bone sialoprotein (BSPII, 21 days after seeding. In vivo implantation in mouse calvaria defects showed significantly more newly mineralized extracellular matrix in the functionalized implant compared to a bare scaffold after 30 days’ implantation, as shown by histological scanning electron microscopy/energy dispersive X-ray microscopy study and calcein injection. We have as well bifunctionalized our BMP-7

  6. Characterization of optically actuated MRI-compatible active needles for medical interventions

    Science.gov (United States)

    Black, Richard J.; Ryu, Seokchang; Moslehi, Behzad; Costa, Joannes M.

    2014-03-01

    The development of a Magnetic Resonance Imaging (MRI) compatible optically-actuated active needle for guided percutaneous surgery and biopsy procedures is described. Electrically passive MRI-compatible actuation in the small diameter needle is provided by non-magnetic materials including a shape memory alloy (SMA) subject to precise fiber laser operation that can be from a remote (e.g., MRI control room) location. Characterization and optimization of the needle is facilitated using optical fiber Bragg grating (FBG) temperature sensors arrays. Active bending of the needle during insertion allows the needle to be accurately guided to even relatively small targets in an organ while avoiding obstacles and overcoming undesirable deviations away from the planned path due to unforeseen or unknowable tissue interactions. This feature makes the needle especially suitable for use in image-guided surgical procedures (ranging from MRI to CT and ultrasound) when accurate targeting is imperative for good treatment outcomes. Such interventions include reaching small tumors in biopsies, delineating freezing areas in, for example, cryosurgery and improving the accuracy of seed placement in brachytherapy. Particularly relevant are prostate procedures, which may be subject to pubic arch interference. Combining diagnostic imaging and actuation assisted biopsy into one treatment can obviate the need for a second exam for guided biopsy, shorten overall procedure times (thus increasing operating room efficiencies), address healthcare reimbursement constraints and, most importantly, improve patient comfort and clinical outcomes.

  7. EGF increases expression and activity of PAs in preimplantation rat embryos and their implantation rate

    Directory of Open Access Journals (Sweden)

    Har-Vardi Iris

    2007-01-01

    Full Text Available Abstract Background Embryo implantation plays a major role in embryogenesis and the outcome of pregnancy. Plasminogen activators (PAs have been implicated in mammalian fertilization, early stages of development and embryo implantation. As in-vitro developing embryos resulted in lower implantation rate than those developed in-vivo we assume that a reduced PAs activity may be involved. In the present work we studied the effect of EGF on PAs activity, quantity and embryo implantation. Methods Zygotes were flushed from rat oviducts on day one of pregnancy and grown in-vitro in R1ECM supplemented with EGF (10 ng/ml and were grown up to the blastocyst stage. The control groups were grown in the same medium without EGF. The distribution and quantity of the PAs were examined using fluorescence immunohistochemistry followed by measurement of PAs activity using the chromogenic assay. Implantation rate was studied using the embryo donation model. Results PAs distribution in the embryos was the same in EGF treated and untreated embryos. Both PAs were localized in the blastocysts' trophectoderm, supporting the assumption that PAs play a role in the implantation process in rats. EGF increased the quantity of uPA at all stages studied but the 8-cell stage as compared with controls. The tissue type PA (tPA content was unaffected except the 8-cell stage, which was increased. The activity of uPA increased gradually towards the blastocyst stage and more so due to the presence of EGF. The activity of tPA did not vary with the advancing developmental stages although it was also increased by EGF. The presence of EGF during the preimplantation development doubled the rate of implantation of the treated group as compared with controls.

  8. Controlling the Biomimetic Implant Interface: Modulating Antimicrobial Activity by Spacer Design

    Science.gov (United States)

    Wisdom, Cate; Vanoosten, Sarah Kay; Boone, Kyle W.; Khvostenko, Dmytro; Arnold, Paul M.; Snead, Malcolm L.; Tamerler, Candan

    2016-08-01

    Surgical site infection is a common cause of post-operative morbidity, often leading to implant loosening, ultimately requiring revision surgery, increased costs and worse surgical outcomes. Since implant failure starts at the implant surface, creating and controlling the bio-material interface will play a critical role in reducing infection while improving host cell-to-implant interaction. Here, we engineered a biomimetic interface based upon a chimeric peptide that incorporates a titanium binding peptide (TiBP) with an antimicrobial peptide (AMP) into a single molecule to direct binding to the implant surface and deliver an antimicrobial activity against S. mutans and S. epidermidis, two bacteria which are linked with clinical implant infections. To optimize antimicrobial activity, we investigated the design of the spacer domain separating the two functional domains of the chimeric peptide. Lengthening and changing the amino acid composition of the spacer resulted in an improvement of minimum inhibitory concentration by a three-fold against S. mutans. Surfaces coated with the chimeric peptide reduced dramatically the number of bacteria, with up to a nine-fold reduction for S. mutans and a 48-fold reduction for S. epidermidis. Ab initio predictions of antimicrobial activity based on structural features were confirmed. Host cell attachment and viability at the biomimetic interface were also improved compared to the untreated implant surface. Biomimetic interfaces formed with this chimeric peptide offer interminable potential by coupling antimicrobial and improved host cell responses to implantable titanium materials, and this peptide based approach can be extended to various biomaterials surfaces.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

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

    2015-01-01

    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. 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. 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. 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.

  11. A reliability study on brain activation during active and passive arm movements supported by an MRI-compatible robot.

    Science.gov (United States)

    Estévez, Natalia; Yu, Ningbo; Brügger, Mike; Villiger, Michael; Hepp-Reymond, Marie-Claude; Riener, Robert; Kollias, Spyros

    2014-11-01

    In neurorehabilitation, longitudinal assessment of arm movement related brain function in patients with motor disability is challenging due to variability in task performance. MRI-compatible robots monitor and control task performance, yielding more reliable evaluation of brain function over time. The main goals of the present study were first to define the brain network activated while performing active and passive elbow movements with an MRI-compatible arm robot (MaRIA) in healthy subjects, and second to test the reproducibility of this activation over time. For the fMRI analysis two models were compared. In model 1 movement onset and duration were included, whereas in model 2 force and range of motion were added to the analysis. Reliability of brain activation was tested with several statistical approaches applied on individual and group activation maps and on summary statistics. The activated network included mainly the primary motor cortex, primary and secondary somatosensory cortex, superior and inferior parietal cortex, medial and lateral premotor regions, and subcortical structures. Reliability analyses revealed robust activation for active movements with both fMRI models and all the statistical methods used. Imposed passive movements also elicited mainly robust brain activation for individual and group activation maps, and reliability was improved by including additional force and range of motion using model 2. These findings demonstrate that the use of robotic devices, such as MaRIA, can be useful to reliably assess arm movement related brain activation in longitudinal studies and may contribute in studies evaluating therapies and brain plasticity following injury in the nervous system.

  12. Activation and thermal stability of ultra-shallow B+-implants in Ge

    DEFF Research Database (Denmark)

    Yates, B. R.; Darby, B. L.; Petersen, Dirch Hjorth;

    2012-01-01

    The activation and thermal stability of ultra-shallow B+ implants in crystalline (c-Ge) and preamorphized Ge (PA-Ge) following rapid thermal annealing was investigated using micro Hall effect and ion beam analysis techniques. The residual implanted dose of ultra-shallow B+ implants in Ge...... from 5.0 × 1013 to 5.0 × 1015 cm-2 was studied using micro Hall effect measurements after annealing at 400-600 °C for 60 s. For both c-Ge and PA-Ge, a large fraction of the implanted dose is rendered inactive due to the formation of a presumable B-Ge cluster. The B lattice location in samples annealed...

  13. EFFECT OF COPPER IMPLANTATION ON ANTIBACTERIAL ACTIVITY OF AUSTENITIC STAINLESS STEEL

    Institute of Scientific and Technical Information of China (English)

    J. Xiong; B.F. Xu; H.W. Ni; P.Y. Xiong; Z.G. Dan

    2004-01-01

    Antibacterial activity has been studied by copper ion implantation into 0Cr18Ni9 stainless steel.Ions extracted from a metal vapor vacuum arc (MEWA) are sourced with 60-100keV energy and a dose range (0.2-2.0)×1017 ions cm-2. Saturation doses, surface concentration were calculated and the relationships between energy, dose and antibacterial activity were analyzed.Novel phases such as Fe4Cu3 and Cu0.81Ni0-19 were found after copper implantation by X-ray diffraction. The novel phases effects on antibacterial activity have been investigated. The results show that saturation dose varies with the ions′energy. Antibacterial activity has close relation with copper's concentration in implanted layer and Cu-rich phase.

  14. Apposition to endometrial epithelial cells activates mouse blastocysts for implantation.

    Science.gov (United States)

    Ruane, Peter T; Berneau, Stéphane C; Koeck, Rebekka; Watts, Jessica; Kimber, Susan J; Brison, Daniel R; Westwood, Melissa; Aplin, John D

    2017-09-01

    How do interactions between blastocyst-stage embryos and endometrial epithelial cells regulate the early stages of implantation in an in vitro model? Mouse blastocyst apposition with human endometrial epithelial cells initiates trophectoderm differentiation to trophoblast, which goes on to breach the endometrial epithelium. In vitro models using mouse blastocysts and human endometrial cell lines have proven invaluable in the molecular characterisation of embryo attachment to endometrial epithelium at the onset of implantation. Genes involved in embryonic breaching of the endometrial epithelium have not been investigated in such in vitro models. This study used an established in vitro model of implantation to examine cellular and molecular interactions during blastocyst attachment to endometrial epithelial cells. Mouse blastocysts developed from embryonic day (E) 1.5 in vitro were hatched and co-cultured with confluent human endometrial adenocarcinoma-derived Ishikawa cells in serum-free medium. A scale of attachment stability based on blastocyst oscillation upon agitation was devised. Blastocysts were monitored for 48 h to establish the kinetics of implantation, and optical sectioning using fluorescence microscopy revealed attachment and invasion interfaces. Quantitative PCR was used to determine blastocyst gene expression. Data from a total of 680 mouse blastocysts are reported, with 3-6 experimental replicates. T-test and ANOVA analyses established statistical significance at P cells over the first 24 h of co-culture, with intermediate and stable attachment occurring from 28 h (E5.5 + 4 h) in a hormone-independent manner. Attached embryos fixed after 48 h (E6.5) frequently exhibited outgrowths, characterised morphologically and with antibody markers as trophoblast giant cells (TGCs), which had breached the Ishikawa cell layer. Beginning co-culture at E5.5 also resulted in intermediate and stable attachment from E5.5 + 4 h; however, these embryos did not go on to

  15. Brain Activities Associated with Graphic Emoticons: An fMRI Study

    Science.gov (United States)

    Yuasa, Masahide; Saito, Keiichi; Mukawa, Naoki

    In this paper, we describe the brain activities that are associated with graphic emoticons by using functional MRI (fMRI). We use various types of faces from abstract to photorealistic in computer network applications. A graphics emoticon is an abstract face in communication over computer network. In this research, we created various graphic emoticons for the fMRI study and the graphic emoticons were classified according to friendliness and level of arousal. We investigated the brain activities of participants who were required to evaluate the emotional valence of the graphic emoticons (happy or sad). The experimental results showed that not only the right inferior frontal gyrus and the cingulate gyrus, but also the inferior and middle temporal gyrus and the fusiform gyrus, were found to be activated during the experiment. Forthermore, it is possible that the activation of the right inferior frontal gyrus and the cingulate gyrus is related to the type of abstract face. Since the inferior and middle temporal gyrus were activated, even though the graphic emoticons are static, we may perceive graphic emoticons as dynamic and living agents. Moreover, it is believed that text and graphics emoticons play an important role in enriching communication among users.

  16. Incremental Activation Detection for Real-Time fMRI Series Using Robust Kalman Filter

    Directory of Open Access Journals (Sweden)

    Liang Li

    2014-01-01

    Full Text Available Real-time functional magnetic resonance imaging (rt-fMRI is a technique that enables us to observe human brain activations in real time. However, some unexpected noises that emerged in fMRI data collecting, such as acute swallowing, head moving and human manipulations, will cause much confusion and unrobustness for the activation analysis. In this paper, a new activation detection method for rt-fMRI data is proposed based on robust Kalman filter. The idea is to add a variation to the extended kalman filter to handle the additional sparse measurement noise and a sparse noise term to the measurement update step. Hence, the robust Kalman filter is designed to improve the robustness for the outliers and can be computed separately for each voxel. The algorithm can compute activation maps on each scan within a repetition time, which meets the requirement for real-time analysis. Experimental results show that this new algorithm can bring out high performance in robustness and in real-time activation detection.

  17. Motor association cortex activity in Parkinson`s disease. A functional MRI study

    Energy Technology Data Exchange (ETDEWEB)

    Tada, Yukiko [Yamaguchi Univ., Ube (Japan). School of Medicine

    1998-08-01

    The purpose of this study was to examine the activation of motor association cortex using functional magnetic resonance imaging (fMRI) in patients with Parkinson`s disease (PD) and control subjects during performed hand movements. There were 26 patients with PD (12 patients with Hoehn and Yahr stage I-II, 14 patients with stage III) and 8 control subjects. Functional imaging was performed using a 1.5 tesla MRI system equipped with a single-shot, echo-planar pulse sequence. The significant signal changes were observed within the primary sensorimotor area, the supplementary motor area (SMA), and the parietal association area in both PD and control subjects. In PD subjects, the SMA was less activated than in control subjects; there were significant differences in the number of pixels activated in SMA between control and Yahr III group (p<0.01), and between Yahr I-II and Yahr III group (p<0.01). Our results demonstrated that movement related cerebral activity in the SMA is reduced in PD subjects, consistent with previously published data using other methods. It is well known from anatomical studies that one of the major cortical outputs of the basal ganglia is the SMA. This may explain the hypoactivation of the SMA in PD. Studies using fMRI provide a promising method not only for localizing cortical activation related to voluntary movements but also for investigating pathophysiology of movement disorders. (author)

  18. Incremental activation detection for real-time fMRI series using robust Kalman filter.

    Science.gov (United States)

    Li, Liang; Yan, Bin; Tong, Li; Wang, Linyuan; Li, Jianxin

    2014-01-01

    Real-time functional magnetic resonance imaging (rt-fMRI) is a technique that enables us to observe human brain activations in real time. However, some unexpected noises that emerged in fMRI data collecting, such as acute swallowing, head moving and human manipulations, will cause much confusion and unrobustness for the activation analysis. In this paper, a new activation detection method for rt-fMRI data is proposed based on robust Kalman filter. The idea is to add a variation to the extended kalman filter to handle the additional sparse measurement noise and a sparse noise term to the measurement update step. Hence, the robust Kalman filter is designed to improve the robustness for the outliers and can be computed separately for each voxel. The algorithm can compute activation maps on each scan within a repetition time, which meets the requirement for real-time analysis. Experimental results show that this new algorithm can bring out high performance in robustness and in real-time activation detection.

  19. Modeling inter-subject variability in fMRI activation location: A Bayesian hierarchical spatial model

    Science.gov (United States)

    Xu, Lei; Johnson, Timothy D.; Nichols, Thomas E.; Nee, Derek E.

    2010-01-01

    Summary The aim of this work is to develop a spatial model for multi-subject fMRI data. There has been extensive work on univariate modeling of each voxel for single and multi-subject data, some work on spatial modeling of single-subject data, and some recent work on spatial modeling of multi-subject data. However, there has been no work on spatial models that explicitly account for inter-subject variability in activation locations. In this work, we use the idea of activation centers and model the inter-subject variability in activation locations directly. Our model is specified in a Bayesian hierarchical frame work which allows us to draw inferences at all levels: the population level, the individual level and the voxel level. We use Gaussian mixtures for the probability that an individual has a particular activation. This helps answer an important question which is not addressed by any of the previous methods: What proportion of subjects had a significant activity in a given region. Our approach incorporates the unknown number of mixture components into the model as a parameter whose posterior distribution is estimated by reversible jump Markov Chain Monte Carlo. We demonstrate our method with a fMRI study of resolving proactive interference and show dramatically better precision of localization with our method relative to the standard mass-univariate method. Although we are motivated by fMRI data, this model could easily be modified to handle other types of imaging data. PMID:19210732

  20. Anti-implantation effect of droloxifene in rats and its relationship with anti-estrogenic activity

    Institute of Scientific and Technical Information of China (English)

    Yong HUANG; Yu SHEN; Ying FENG; Lin CAO; Ying LENG

    2005-01-01

    Aim: To investigate the anti-implantation effect of droloxifene and study the possible relationship between the anti-estrogenic activity of droloxifene and its antiimplantation effect. Methods: Pregnant rats were treated orally with droloxifene at 10:00 AM on d 2 at doses of 1.25-20 mg/kg to observe anti-implantation effects,and then doses of 14 mg/kg or 2.5 mg/kg were given at different time on d 2 to d 5to determine the optimal administration time for anti-implantation effects. Pregnant rats were treated with a combination of droloxifene (2.5 mg/kg, ig) and E2 (0.5-8.0 μg/kg, sc) on the optimal administration time to observe the antagonistic effect of external estrogen on the anti-implantation effect of droloxmene. Serum estrogen and progesterone levels were measured by carrying out radioimmunoas says on d 1 to d 6 in droloxifene-treated and control rats to determine the surge time for nidatory estrogen and the effect of droloxifene on ovary function. Results:Droloxifene has anti-implantation effects in rats. The optimal oral administration time was at 22:00 PM on d 4, which was after the surge time for nidatory estrogen (on d 4 at 10:00 AM). This suggests that the anti-implantation effect of droloxifene is not attributable to antagonism of the surge in secretion of nidatory estrogen.External estrogen did not antagonize the anti-implantation effect of droloxifene.Droloxifene had no effect on the serum levels of estrogen and progesterone on d 5 or d 6 when administered on d 4 at 22:00 PM. Conclusion: Droloxifene has an anti-implantation effect in rats, and the effect appears to be not completely due to its anti-estrogenic activity.

  1. Bioreactor activated graft material for early implant fixation in bone

    DEFF Research Database (Denmark)

    Snoek Henriksen, Susan; Ding, Ming; Overgaard, Søren

    2011-01-01

    . The superficial part was used for mechanical testing and micro-CT scanning, and the profound part for histomorphometry. Push-out tests were performed on an 858 Bionix MTS hydraulic materials testing machine (MTS Systems Corporation, USA). Shear mechanical properties between implant and newly generated bone were......: No significant differences regarding failure energy (kJ/m2, p=0.44) or ultimate shear strength (MPa, p=0.17) could be seen. Shear stiffness (MPa) was significantly higher for the allograft group (p=0.04). Group 2: No significant differences regarding failure energy (p=0.11) or shear stiffness (p=0.52) could...

  2. The effects of physical activity on functional MRI activation associated with cognitive control in children: a randomized controlled intervention

    Directory of Open Access Journals (Sweden)

    Laura eChaddock-Heyman

    2013-03-01

    Full Text Available This study used functional magnetic resonance imaging (fMRI to examine the influence of a 9-month physical activity program on task-evoked brain activation during childhood. The results demonstrated that 8- to 9-year-old children who participated in 60+ minutes of physical activity, 5 days per week, for 9 months, showed decreases in fMRI brain activation in the right anterior prefrontal cortex coupled with within-group improvements in performance on a task of attentional and interference control. Children assigned to a wait list control group did not show changes in brain function. Furthermore, at post-test, children in the physical activity group showed similar anterior frontal brain patterns and incongruent accuracy rates to a group of college-aged young adults. Children in the wait list control group still differed from the young adults in terms of anterior prefrontal activation and performance at post-test. There were no significant changes in fMRI activation in the anterior cingulate cortex for either group. These results suggest that physical activity during childhood may enhance specific elements of prefrontal cortex function involved in cognitive control.

  3. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... field of the MRI unit, metal and electronic items are not allowed in the exam room. In addition to affecting the MRI images, ... damaged pins, hairpins, metal zippers and similar metallic items, which can distort ... In most cases, an MRI exam is safe for patients with metal implants, except ...

  4. Limited role of gadolinium to detect active sacroiliitis on MRI in juvenile spondyloarthritis

    Energy Technology Data Exchange (ETDEWEB)

    Herregods, N.; Leus, A.; Verstraete, K.; Jans, L. [Ghent University Hospital, Department of Radiology and Medical Imaging, Ghent (Belgium); Jaremko, J.L. [University of Alberta Hospital, Department of Radiology and Diagnostic Imaging, Edmonton, AB (Canada); Baraliakos, X. [Ruhr-University Bochum, Rheumazentrum Ruhrgebiet, Herne (Germany); Dehoorne, J. [Ghent University Hospital, Department of Pediatric Rheumatology, Ghent (Belgium)

    2015-11-15

    The aim of this study is to determine the added diagnostic value of contrast-enhanced (CE) magnetic resonance imaging (MRI) compared to routine non contrast-enhanced MRI to detect active sacroiliitis in clinically juvenile spondyloarthritis (JSpA). A total of 80 children clinically suspected for sacroiliitis prospectively underwent MRI of the sacroiliac (SI) joints. Axial and coronal T1-weighted (T1), Short-tau inversion recovery (STIR) and fat-saturated T1-weighted gadolinium-DTPA (Gd) contrast-enhanced (T1/Gd) sequences were obtained. The presence of bone marrow edema (BME), capsulitis, enthesitis, high intra-articular STIR signal, synovial enhancement and a global diagnostic impression of the MRI for diagnosis of sacroiliitis was recorded. STIR and T1/Gd sequences had 100 % agreement for depiction of BME, capsulitis and enthesitis. High intra-articular STIR signal was seen in 18/80 (22.5 %) patients, 15 (83 %) of whom also showed synovial enhancement in the T1/Gd sequence. Sensitivity (SN) and specificity (SP) for a clinical diagnosis of JSpA were similar for high STIR signal (SN = 33 %, SP = 85 %) and T1/Gd synovial enhancement (SN = 36 %, SP = 92 %). Positive likelihood ratio (LR+) for JSpA was twice as high for synovial enhancement than high STIR signal (4.5 compared to 2.2). Global diagnostic impression was similar (STIR: SN = 55 %, SP = 87 %, LR + =4.2; T1/Gd: SN = 55 %, SP = 92 %, LR + = 6.9). MRI without contrast administration is sufficient to identify bone marrow edema, capsulitis and retroarticular enthesitis as features of active sacroiliitis in juvenile spondyloarthritis. In selected cases when high STIR signal in the joint is the only finding, gadolinium-enhanced images may help to confirm the presence of synovitis. (orig.)

  5. MRI features of pediatric cerebral paragonimiasis in the active stage.

    Science.gov (United States)

    Zhang, Jin Song; Huan, Yi; Sun, Li Jun; Zhang, Guang Yun; Ge, Ya Li; Zhao, Hai Tao

    2006-04-01

    We retrospectively reviewed the MR images of the brains of six children (age = 5-13 years) who had cerebral paragonimiasis in the early active stage. Diagnosis was based on a positive antibody test enzyme-linked immunosorbent assay (ELISA) for paragonimiasis in serum. The most common finding (in five patients) was irregular hemorrhage of various degrees. Moreover, in three cases some multiple irregular lesions with surrounding edema appeared to be conglomerated and aggregated. The rare appearance (in one patient) was a "tunnel sign," which showed the migrating track of the adult worm. In one patient with abscess and minimal hemorrhage, diffusion-weighted imaging (DWI) showed a heterogeneous high signal of lesions. Other findings included slight (one patient) or marked (one patient) irregular contrast enhancement, and large edematous areas surrounding small centers of hemorrhage (two patients). MR findings of conglomerated lesions with hemorrhage or tunnel sign may help to establish the diagnosis of active-stage cerebral paragonimiasis.

  6. Active Middle Ear Implantation: Long-term Medical and Technical Follow-up, Implant Survival, and Complications

    NARCIS (Netherlands)

    Zwartenkot, J.W.; Mulder, J.J.S.; Snik, A.F.M.; Cremers, C.W.R.J.; Mylanus, E.A.M.

    2016-01-01

    OBJECTIVE: To evaluate the long-term medical and technical results, implant survival, and complications of the semi-implantable vibrant soundbridge (VSB), otologics middle ear transducer (MET), and the otologics fully implantable ossicular stimulator (FIMOS). STUDY DESIGN: Retrospective cohort study

  7. Visual activity predicts auditory recovery from deafness after adult cochlear implantation.

    Science.gov (United States)

    Strelnikov, Kuzma; Rouger, Julien; Demonet, Jean-François; Lagleyre, Sebastien; Fraysse, Bernard; Deguine, Olivier; Barone, Pascal

    2013-12-01

    Modern cochlear implantation technologies allow deaf patients to understand auditory speech; however, the implants deliver only a coarse auditory input and patients must use long-term adaptive processes to achieve coherent percepts. In adults with post-lingual deafness, the high progress of speech recovery is observed during the first year after cochlear implantation, but there is a large range of variability in the level of cochlear implant outcomes and the temporal evolution of recovery. It has been proposed that when profoundly deaf subjects receive a cochlear implant, the visual cross-modal reorganization of the brain is deleterious for auditory speech recovery. We tested this hypothesis in post-lingually deaf adults by analysing whether brain activity shortly after implantation correlated with the level of auditory recovery 6 months later. Based on brain activity induced by a speech-processing task, we found strong positive correlations in areas outside the auditory cortex. The highest positive correlations were found in the occipital cortex involved in visual processing, as well as in the posterior-temporal cortex known for audio-visual integration. The other area, which positively correlated with auditory speech recovery, was localized in the left inferior frontal area known for speech processing. Our results demonstrate that the visual modality's functional level is related to the proficiency level of auditory recovery. Based on the positive correlation of visual activity with auditory speech recovery, we suggest that visual modality may facilitate the perception of the word's auditory counterpart in communicative situations. The link demonstrated between visual activity and auditory speech perception indicates that visuoauditory synergy is crucial for cross-modal plasticity and fostering speech-comprehension recovery in adult cochlear-implanted deaf patients.

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

    Energy Technology Data Exchange (ETDEWEB)

    Frank, Steven J., E-mail: sjfrank@mdanderson.org [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Texas (United States); Johansen, Mary J. [Department of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, Texas (United States); Martirosyan, Karen S. [Department of Physics and Astronomy, The University of Texas at Brownsville, Texas (United States); Gagea, Mihai; Van Pelt, Carolyn S.; Borne, Agatha [Department of Veterinary Medicine, Surgery, and Pathology, The University of Texas MD Anderson Cancer Center, Texas (United States); Carmazzi, Yudith; Madden, Timothy [Department of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, Texas (United States)

    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

  9. Identification by functional MRI of human cerebral region activated by taste stimulation

    Energy Technology Data Exchange (ETDEWEB)

    Kakimoto, Naoya [Osaka Univ. (Japan). Faculty of Dentistry

    2000-09-01

    The purpose of this study was the examination of possible imaging of the primary taste region of human cerebral cortex by functional MRI (fMRI). Subjects were 19-36 years old, healthy adult male and female volunteers given information concerning the purpose, significance and method of the study. MRI equipment was 1.5 T Signa Horizon (GE) with Head Coil. Images were processed by the software FuncTool on the Advantage Windows Workstation (GE). Taste stimulation was done by swab bearing the solution of 4% quinine hydrochloride, 20% sodium chloride or distilled water (control) or by dripping from the syringe of the solutions, 8% tartaric acid or 80% sugar. Preliminary examinations with the swab suggested the possibility of the identification. Further, with use of dripping apparatus, the taste active region was shown to be identified by fMRI and of which area tended to be larger in male than in female: a significant difference was seen for the quinine hydrochloride. As above, the method was suggested to be a diagnostic mean for the taste perception. (K.H.)

  10. Long-term T2 and Qualitative MRI Morphology After First-Generation Knee Autologous Chondrocyte Implantation

    DEFF Research Database (Denmark)

    Salzmann, Gian M; Erdle, Benjamin; Porichis, Stella;

    2014-01-01

    significantly correlated with the mKOSS (P quantitative imaging data and clinical function. Qualitative imaging data are much better correlated to functional outcomes.......BACKGROUND: There are several reports on long-term clinical outcomes after autologous chondrocyte implantation (ACI) for knee cartilage defect treatment. Few published articles have evaluated defect quality using quantitative magnetic resonance (MR) imaging techniques. PURPOSE: To evaluate clinical...... outcomes and the quality of repair tissue (RT) after first-generation periosteum-covered ACI (ACI-P) using qualitative MR outcomes and T2-weighted relaxation times. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: All patients (n = 86) who underwent knee joint ACI-P (from 1997 through 2001...

  11. Lesion Activity on Brain MRI in a Chinese Population with Unilateral Optic Neuritis.

    Science.gov (United States)

    Lai, Chuntao; Chang, Qinglin; Tian, Guohong; Wang, Jiawei; Yin, Hongxia; Liu, Wu

    2015-01-01

    Longitudinal studies have shown that brain white matter lesions are strong predictors of the conversion of unilateral optic neuritis to multiple sclerosis (MS) in Caucasian populations. Consequently brain MRI criteria have been developed to improve the prediction of the development of clinically definite multiple sclerosis (CDMS). In Asian populations, optic neuritis may be the first sign of classical or optic-spinal MS. These signs add to the uncertainty regarding brain MRI changes with respect to the course of unilateral optic neuritis. The aim of this study was to examine the association between brain lesion activity and conversion to CDMS in Chinese patients with unilateral optic neuritis. A small prospective cohort study of 40 consecutive Chinese patients who presented with unilateral optic neuritis was conducted. Brain lesion activity was recorded as the incidence of Gd-enhanced lesions and new T2 lesions. Brain lesions on MRI that were characteristic of MS were defined according to the 2010 revisions of the McDonald criteria. The primary endpoint was the development of CDMS. We found that nineteen patients (48%) had brain lesions that were characteristic of MS on the initial scan. One of these patients (3%) had Gd-enhanced brain lesions. A significantly lower percentage of the patients (10%, poptic neuritis; however, these patients exhibit low lesion activity. The predictive value of brain lesion activity for CDMS requires investigation in additional patients.

  12. Neural activity during production of rorschach responses: An fMRI study.

    Science.gov (United States)

    Giromini, Luciano; Viglione, Donald J; Zennaro, Alessandro; Cauda, Franco

    2017-02-10

    Recently, a lot of effort has been made to ground Rorschach interpretations to their evidence base. To date, however, no studies have yet described, via fMRI, what brain areas get involved when one takes the Rorschach. To fill this gap in the literature, we administered the ten-inkblot stimuli to 26 healthy volunteers during fMRI. Analysis of BOLD signals revealed that, compared to fixating a cross, looking at the Rorschach inkblots while thinking of what they might be associated with higher temporo-occipital and fronto-parietal activations, and with greater activity in some small, sub-cortical regions included in the limbic system. These findings are in line with the traditional conceptualization of the test, as they suggest that taking the Rorschach involves (a) high-level visual processing, (b) top-down as well as bottom-up attentional processes, and (c) perception and processing of emotions and emotional memories.

  13. Active learning based segmentation of Crohns disease from abdominal MRI.

    Science.gov (United States)

    Mahapatra, Dwarikanath; Vos, Franciscus M; Buhmann, Joachim M

    2016-05-01

    This paper proposes a novel active learning (AL) framework, and combines it with semi supervised learning (SSL) for segmenting Crohns disease (CD) tissues from abdominal magnetic resonance (MR) images. Robust fully supervised learning (FSL) based classifiers require lots of labeled data of different disease severities. Obtaining such data is time consuming and requires considerable expertise. SSL methods use a few labeled samples, and leverage the information from many unlabeled samples to train an accurate classifier. AL queries labels of most informative samples and maximizes gain from the labeling effort. Our primary contribution is in designing a query strategy that combines novel context information with classification uncertainty and feature similarity. Combining SSL and AL gives a robust segmentation method that: (1) optimally uses few labeled samples and many unlabeled samples; and (2) requires lower training time. Experimental results show our method achieves higher segmentation accuracy than FSL methods with fewer samples and reduced training effort.

  14. Multiple implantation and multiple annealing of phosphorus doped germanium to achieve n-type activation near the theoretical limit

    Science.gov (United States)

    Kim, Jeehwan; Bedell, Stephen W.; Sadana, Devendra K.

    2012-09-01

    Full activation of n-type dopant in germanium (Ge) reaching to its solid solubility has never been achieved by using ion implantation doping technique. This is because implantation of dopants always leaves defects such as vacancy and interstitials in the Ge crystal. While implantation-induced defects are electrically neutral for the most of semiconductor materials, they are electrically positive for Ge resulting in compensation of n-type dopants. In this Letter, we verified that 5 × 1019 P/cm3 is the maximum active concentration, which can be fully activated in germanium "without leaving implantation damage" per implantation/annealing cycle. The repetition of implantation and annealing of phosphorous (P) with the concentration of 5 × 1019 cm-3 leads to the activation of 1 × 1020 P/cm3 close to its solid solubility limit of 2 × 1020 P/cm3.

  15. Effect of B+ Flux on the electrical activation of ultra-shallow B+ implants in Ge

    DEFF Research Database (Denmark)

    Yates, B.R.; Darby, B.L.; Petersen, Dirch Hjorth;

    2012-01-01

    The residual implanted dose of ultra-shallow B+ implants in Ge was characterized using elastic recoil detection and was determined to correlate well with simulations with a dose loss of 23% due to ion backscattering for 2 keV implants in Ge. The electrical characterization of ultra-shallow B......+ implants at 2 keV to a dose of 5.0×1014 cm-2 at beam currents ranging from 0.4 to 6.4 mA has been studied using micro Hall effect measurements after annealing at 400°C for 60 s. It has been shown that the sheet number increases with beam current across the investigated range with electrical activation...... being 76% higher at 6.4 mA as compared to 0.4mA. However, at 6.4 mA, the electrically active fraction remained low at 11.4%. Structural characterization revealed that the implanted region remained crystalline and amorphization is not able to explain the increased activation. The results suggest...

  16. Cerebral blood oxygenation changes during neuronal activation in stroke patients measured by near infrared spectroscopy and BOLD-functional MRI

    Energy Technology Data Exchange (ETDEWEB)

    Murata, Yoshihiro; Fukaya, Chikashi; Sakatani, Kaoru; Katayama, Yoichi [Nihon Univ., Tokyo (Japan). School of Medicine

    2002-03-01

    Blood Oxygenation Level Dependent (BOLD)-fMRI images areas of activation by detecting a reduced concentration of deoxyhemoglobin during neuronal activity, which is caused by a larger increase in O{sub 2} delivery as compared to O{sub 2} consumption in normal adults. In the present study, near infrared spectroscopy demonstrated an increase of deoxyhemoglobin associated with increases of oxyhemoglobin and total hemoglobin in activation areas of stroke patients, whereas BOLD-fMRI failed to image such activation areas. The findings obtained have serious implications for the application of BOLD-fMRI to patients with brain disorders, since BOLD-fMRI may overlook neuronal activities in these patients. (author)

  17. Thin film based semi-active resonant marker design for low profile interventional cardiovascular MRI devices.

    Science.gov (United States)

    Baysoy, Engin; Yildirim, Dursun Korel; Ozsoy, Cagla; Mutlu, Senol; Kocaturk, Ozgur

    2017-02-01

    A new microfabrication method to produce low profile radio frequency (RF) resonant markers on catheter shafts was developed. A semi-active RF resonant marker incorporating a solenoid and a plate capacitor was constructed on the distal shaft of a 5 Fr guiding catheter. The resulting device can be used for interventional cardiovascular MRI procedures. Unlike current semi-active device visualization techniques that require rigid and bulky analog circuit components (capacitor and solenoid), we fabricated a low profile RF resonant marker directly on guiding the catheter surface by thin film metal deposition and electroplating processes using a modified physical vapor deposition system. The increase of the overall device profile thickness caused by the semi-active RF resonant marker (130 µm thick) was lowered by a factor of 4.6 compared with using the thinnest commercial non-magnetic and rigid circuit components (600 µm thick). Moreover, adequate visibility performance of the RF resonant marker in different orientations and overall RF safety were confirmed through in vitro experiments under MRI successfully. The developed RF resonant marker on a clinical grade 5 Fr guiding catheter will enable several interventional congenital heart disease treatment procedures under MRI.

  18. Activation of arsenic-implanted silicon using an incoherent light source

    Science.gov (United States)

    Powell, R. A.; Yep, T. O.; Fulks, R. T.

    1981-07-01

    We report that continuous, incoherent light from a xenon arc lamp can be used to completely activate implanted Si (100) samples (75As+:100 keV, 1×1015 cm-2) with negligible dopant redistribution and excellent uniformity (sheet resistivity variation less than ±2% over a 3-in.-diam wafer). An entire 3-in. wafer could be activated in only about 10 sec without relative motion of wafer and light beam. The extent to which implant damage was removed by the incoherent light anneal is qualitatively indicated by the carrier mobilities which were within 10% of single-crystal values.

  19. Self-regulation of human brain activity using simultaneous real-time fMRI and EEG neurofeedback

    CERN Document Server

    Zotev, Vadim; Yuan, Han; Misaki, Masaya; Bodurka, Jerzy

    2014-01-01

    Neurofeedback is a promising approach for non-invasive modulation of human brain activity with applications for treatment of mental disorders and enhancement of brain performance. Neurofeedback techniques are commonly based on either electroencephalography (EEG) or real-time functional magnetic resonance imaging (rtfMRI). Advances in simultaneous EEG-fMRI have made it possible to combine the two approaches. Here we report the first implementation of simultaneous multimodal rtfMRI and EEG neurofeedback (rtfMRI-EEG-nf). It is based on a novel system for real-time integration of simultaneous rtfMRI and EEG data streams. We applied the rtfMRI-EEG-nf to training of emotional self-regulation in healthy subjects performing a positive emotion induction task based on retrieval of happy autobiographical memories. The participants were able to simultaneously regulate their BOLD fMRI activation of the left amygdala and frontal EEG power asymmetry in the high-beta band using the rtfMRI-EEG-nf. Our proof-of-concept results...

  20. Relationship between saccadic eye movements and cortical activity as measured by fMRI

    DEFF Research Database (Denmark)

    Kimmig, H.; Greenlee, M.W.; Gondan, Matthias;

    2001-01-01

    quantitative changes in cortical activity associated with qualitative changes in the saccade task for comparable levels of saccadic activity. All experiments required the simultaneous acquisition of eye movement and fMRI data. For this purpose we used a new high-resolution limbus-tracking technique...... that repeated processing of saccades is integrated over time in the BOLD response. In contrast, there was no comparable BOLD change with variation of saccade amplitude. This finding speaks for a topological rather than activity-dependent coding of saccade amplitudes in most cortical regions. In the experiments...

  1. Antimicrobial activity of the surface coatings on TiAlZr implant biomaterial.

    Science.gov (United States)

    Ionita, Daniela; Grecu, Mihaela; Ungureanu, Camelia; Demetrescu, Ioana

    2011-12-01

    This study is devoted to antimicrobial activity of new surface coatings on TiAlZr. Ti alloys such as TiAlZr are used as implant biomaterials, but, despite the good behavior of such alloys in simulated conditions, bacterial infections appear after the introduction of an implant into the body. The infections are typically caused by the adherence and colonization of bacteria on the surfaces of the implants. The study presents preparation and surface morphology characterization of coatings obtained via anodizing, as well as biomimetic coatings with hydroxyapatite and silver ions with and without antibiotic. The percentage inhibition of Escherichia coli bacteria growth was evaluated for each of the studied coating, and a Trojan-horse model of silver nanoparticles (nAg) antibacterial activity at interface was proposed. Such coatings could be more important taking into account that antibacterial treatments with antibiotics are becoming less effective due to their intensive use.

  2. Effects of breed and zeranol implantation on serum insulin, somatomedin-like activity and fibroblast proliferative activity.

    Science.gov (United States)

    Wangsness, P J; Olsen, R F; Martin, R J

    1981-01-01

    Twenty-eight Suffolk-sired (Sx) and 28 Finnsheep-sired (Fx) lambs were implanted with either 0 or 12 mg zeranol. Zeranol significantly increased average daily gain over that of controls. Serum taken at biweekly intervals for 6 weeks was assayed for insulin, somatomedin-like activity (Sm) and fibroblast proliferative activity (FPA). Insulin appeared to increase with time, but there were no consistent time changes for FPA or Sm. Serum insulin concentration was higher (P less than .05) in implanted lambs than in controls (33.4 vs 25.6 microU/ml). Unlike insulin, serum Sm and FPA were not affected by zeranol implantation, and, thus, these serum factors appeared not to be involved in zeranol-stimulated growth. Sm was higher in the faster growing Sx lambs than in the slower growing Fx lambs. Thus, serum Sm activity may be involved in normal regulation of growth.

  3. Surface modification of TiO2 coatings by Zn ion implantation for improving antibacterial activities

    Indian Academy of Sciences (India)

    Xiaobing Zhao; Jiashen Yang; Jing You

    2016-02-01

    TiO$_2$ coating has been widely applied in orthopaedic and dental implants owing to its excellent mechanical and biological properties. However, one of the biggest complications of TiO$_2$ coating is implant-associated infections. The aim of this work is to improve the antibacterial activity of plasma-sprayed TiO$_2$ coatings by plasma immersion ion implantation (PIII) using zinc (Zn) ions. Results indicate that the as-sprayed TiO$_2$ coating is mainly composed of rutile phase. Zn-PIII modification does not change the phase compositions and the surface morphologies of TiO$_2$ coatings, while change their hydrophilicity. Zn-implanted TiO$_2$ coatings can inhibit the growth of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), and the ability to inhibit S. aureus is greater than that to E. coli. Zn ion release and reactive oxygen species may be attributed to improving the antibacterial activity of TiO$_2$ coating. Therefore, Zn-PIII TiO$_2$ coatings on titanium suggest promising candidates for orthopaedic and dental implants.

  4. An active learning approach to education in MRI technology for the biomedical engineering curriculum

    DEFF Research Database (Denmark)

    Hanson, Lars G.

    2012-01-01

    sense expressed in the math is in focus. Unfortunately, the nuclear dynamics happen in four dimensions, and are therefore not well suited for illustration on blackboard. 3D movies are more appropriate, but they do not encourage active learning. The typical solution employed by educators is hand waving...... (literally), since arm motions can to a limited extent be used to illustrate nuclear dynamics. Many students find this confusing, however, and students who do not grasp the meaning during lectures, are left in a bad position. For this reason, educational software was developed over the last decade (the Bloch...... Simulator). It is freely available and can be run directly from the software homepage that also links to YouTube software presentations aimed at educators and students who have already gotten a first introduction to MRI concepts. The software is mainly aimed at educators for interactive demonstration of MRI...

  5. An active learning approach to education in MRI technology for the biomedical engineering curriculum

    DEFF Research Database (Denmark)

    Hanson, L.G.

    sense expressed in the math is in focus. Unfortunately, the nuclear dynamics happen in four dimensions, and are therefore not well suited for illustration on blackboard. 3D movies are more appropriate, but they do not encourage active learning. The typical solution employed by educators is hand waving...... (literally), since arm motions can to a limited extent be used to illustrate nuclear dynamics. Many students find this confusing, however, and students who do not grasp the meaning during lectures, are left in a bad position. For this reason, educational software was developed over the last decade (the Bloch...... Simulator). It is freely available and can be run directly from the software homepage that also links to YouTube software presentations aimed at educators and students who have already gotten a first introduction to MRI concepts. The software is mainly aimed at educators for interactive demonstration of MRI...

  6. Motion or activity: their role in intra- and inter-subject variation in fMRI

    DEFF Research Database (Denmark)

    Lund, Torben E; Nørgaard, Minna D; Rostrup, Egill;

    2005-01-01

    MRI to pre-surgical planning because of a higher requirement for intra-subject precision. The purpose of this study was to investigate the impact of residual movement artefacts on intra-subject and inter-subject variability in the observed fMRI activation. Ten subjects were examined using three different...... word-generation tasks. Two of the subjects were examined 10 times on 10 different days using the same paradigms. We systematically investigated one approach of correcting for residual movement effects: the inclusion of regressors describing movement-related effects in the design matrix of a General...... Linear Model (GLM). The data were analysed with and without modeling the residual movement artefacts and the impact on inter-session variance was assessed using F-contrasts. Inclusion of motion parameters in the analysis significantly reduced both the intra-subject as well as the inter-subject-variance...

  7. CHANGES IN REGIONAL BRAIN ACTIVATION RELATED TO DEPRESSIVE STATE: A 2-YEAR LONGITUDINAL FUNCTIONAL MRI STUDY.

    Science.gov (United States)

    Opmeer, Esther M; Kortekaas, Rudie; van Tol, Marie-José; Renken, Remco J; Demenescu, Liliana R; Woudstra, Saskia; Ter Horst, Gert J; van Buchem, Mark A; van der Wee, Nic J A; Veltman, Dick J; Aleman, André

    2016-01-01

    Abnormal brain activations during processing of emotional facial expressions in depressed patients have been demonstrated. We investigated the natural course of brain activation in response to emotional faces in depression, indexed by functional magnetic resonance imaging (fMRI) scans preceding and following change in depressive state. We hypothesized a decrease in activation in the amygdala, anterior cingulate cortex (ACC), and insula with a decrease in depressive pathology. A 2-year longitudinal fMRI study was conducted as part of the Netherlands Study of Depression and Anxiety. We included 32 healthy controls and 49 depressed patients. During the second scan, 27 patients were in remission (remitters), the other 22 were not (nonremitters). All participants viewed faces with emotional expressions during scanning. Rostral ACC activation during processing of happy faces was predictive of a decrease in depressive state (PFWE = .003). In addition, remitters showed decreased activation of the insula over time (PFWE = .016), specifically during happy faces. Nonremitters displayed increased abnormalities in emotion recognition circuitry during the second scan compared to the first. No effect of selective serotonin reuptake inhibitor use was observed. Our results demonstrate that rostral ACC activation may predict changes in depressive state even at 2-year outcome. The association between change in depressed state and change in insula activation provides further evidence for the role of the insula in a network maintaining emotional and motivational states. © 2015 Wiley Periodicals, Inc.

  8. Recording event-related activity under hostile magnetic resonance environment: Is multimodal EEG/ERP-MRI recording possible?

    Science.gov (United States)

    Karakaş, H M; Karakaş, S; Ozkan Ceylan, A; Tali, E T

    2009-08-01

    Event-related potentials (ERPs) have high temporal resolution, but insufficient spatial resolution; the converse is true for the functional imaging techniques. The purpose of the study was to test the utility of a multimodal EEG/ERP-MRI technique which combines electroencephalography (EEG) and magnetic resonance imaging (MRI) for a simultaneously high temporal and spatial resolution. The sample consisted of 32 healthy young adults of both sexes. Auditory stimuli were delivered according to the active and passive oddball paradigms in the MRI environment (MRI-e) and in the standard conditions of the electrophysiology laboratory environment (Lab-e). Tasks were presented in a fixed order. Participants were exposed to the recording environments in a counterbalanced order. EEG data were preprocessed for MRI-related artifacts. Source localization was made using a current density reconstruction technique. The ERP waveforms for the MRI-e were morphologically similar to those for the Lab-e. The effect of the recording environment, experimental paradigm and electrode location were analyzed using a 2x2x3 analysis of variance for repeated measures. The ERP components in the two environments showed parametric variations and characteristic topographical distributions. The calculated sources were in line with the related literature. The findings indicated effortful cognitive processing in MRI-e. The study provided preliminary data on the feasibility of the multimodal EEG/ERP-MRI technique. It also indicated lines of research that are to be pursued for a decisive testing of this technique and its implementation to clinical practice.

  9. Classification of autistic individuals and controls using cross-task characterization of fMRI activity

    Directory of Open Access Journals (Sweden)

    Guillaume Chanel

    2016-01-01

    Full Text Available Multivariate pattern analysis (MVPA has been applied successfully to task-based and resting-based fMRI recordings to investigate which neural markers distinguish individuals with autistic spectrum disorders (ASD from controls. While most studies have focused on brain connectivity during resting state episodes and regions of interest approaches (ROI, a wealth of task-based fMRI datasets have been acquired in these populations in the last decade. This calls for techniques that can leverage information not only from a single dataset, but from several existing datasets that might share some common features and biomarkers. We propose a fully data-driven (voxel-based approach that we apply to two different fMRI experiments with social stimuli (faces and bodies. The method, based on Support Vector Machines (SVMs and Recursive Feature Elimination (RFE, is first trained for each experiment independently and each output is then combined to obtain a final classification output. Second, this RFE output is used to determine which voxels are most often selected for classification to generate maps of significant discriminative activity. Finally, to further explore the clinical validity of the approach, we correlate phenotypic information with obtained classifier scores. The results reveal good classification accuracy (range between 69% and 92.3%. Moreover, we were able to identify discriminative activity patterns pertaining to the social brain without relying on a priori ROI definitions. Finally, social motivation was the only dimension which correlated with classifier scores, suggesting that it is the main dimension captured by the classifiers. Altogether, we believe that the present RFE method proves to be efficient and may help identifying relevant biomarkers by taking advantage of acquired task-based fMRI datasets in psychiatric populations.

  10. Classification of autistic individuals and controls using cross-task characterization of fMRI activity.

    Science.gov (United States)

    Chanel, Guillaume; Pichon, Swann; Conty, Laurence; Berthoz, Sylvie; Chevallier, Coralie; Grèzes, Julie

    2016-01-01

    Multivariate pattern analysis (MVPA) has been applied successfully to task-based and resting-based fMRI recordings to investigate which neural markers distinguish individuals with autistic spectrum disorders (ASD) from controls. While most studies have focused on brain connectivity during resting state episodes and regions of interest approaches (ROI), a wealth of task-based fMRI datasets have been acquired in these populations in the last decade. This calls for techniques that can leverage information not only from a single dataset, but from several existing datasets that might share some common features and biomarkers. We propose a fully data-driven (voxel-based) approach that we apply to two different fMRI experiments with social stimuli (faces and bodies). The method, based on Support Vector Machines (SVMs) and Recursive Feature Elimination (RFE), is first trained for each experiment independently and each output is then combined to obtain a final classification output. Second, this RFE output is used to determine which voxels are most often selected for classification to generate maps of significant discriminative activity. Finally, to further explore the clinical validity of the approach, we correlate phenotypic information with obtained classifier scores. The results reveal good classification accuracy (range between 69% and 92.3%). Moreover, we were able to identify discriminative activity patterns pertaining to the social brain without relying on a priori ROI definitions. Finally, social motivation was the only dimension which correlated with classifier scores, suggesting that it is the main dimension captured by the classifiers. Altogether, we believe that the present RFE method proves to be efficient and may help identifying relevant biomarkers by taking advantage of acquired task-based fMRI datasets in psychiatric populations.

  11. Soluble and particulate Co-Cr-Mo alloy implant metals activate the inflammasome danger signaling pathway in human macrophages: a novel mechanism for implant debris reactivity.

    Science.gov (United States)

    Caicedo, Marco S; Desai, Ronak; McAllister, Kyron; Reddy, Anand; Jacobs, Joshua J; Hallab, Nadim J

    2009-07-01

    Immune reactivity to soluble and particulate implant debris remains the primary cause of aseptic inflammation and implant loosening. However, the intracellular mechanisms that trigger immune cells to sense and respond to exogenous nonbiological agents such as metal particles or metal ions released from orthopedic implants remain unknown. Recent studies in immunology have outlined the importance of the intracellular inflammasome complex of proteins in sensing danger/stress signals triggered by nonbiological agents in the cytosol of macrophages. We hypothesized that metal implant debris can activate the inflammasome pathway in macrophages that causes caspase-1-induced cleavage of intracellular pro-IL-1beta into its mature form, resulting in IL-1beta secretion and induction of a broader proinflammatory response. We tested this hypothesis by examining whether soluble cobalt, chromium, molybdenum, and nickel ions and Co-Cr-Mo alloy particles induce inflammasome- mediated macrophage reactivity. Our results demonstrate that these agents stimulate IL-1beta secretion in human macrophages that is inflammasome mediated (i.e., NADPH-, caspase-1-, Nalp3-, and ASC-dependent). Thus, metal ion- and particle-induced activation of the inflammasome in human macrophages provides evidence of a novel pathway of implant debris-induced inflammation, where contact with implant debris is sensed and transduced by macrophages into a proinflammatory response.

  12. Activated and deactivated functional brain areas in the Deqi state: A functional MRI study.

    Science.gov (United States)

    Huang, Yong; Zeng, Tongjun; Zhang, Guifeng; Li, Ganlong; Lu, Na; Lai, Xinsheng; Lu, Yangjia; Chen, Jiarong

    2012-10-25

    We compared the activities of functional regions of the brain in the Deqi versus non-Deqi state, as reported by physicians and subjects during acupuncture. Twelve healthy volunteers received sham and true needling at the Waiguan (TE5) acupoint. Real-time cerebral functional MRI showed that compared with non-sensation after sham needling, true needling activated Brodmann areas 3, 6, 8, 9, 10, 11, 13, 20, 21, 37, 39, 40, 43, and 47, the head of the caudate nucleus, the parahippocampal gyrus, thalamus and red nucleus. True needling also deactivated Brodmann areas 1, 2, 3, 4, 5, 6, 7, 9, 10, 18, 24, 31, 40 and 46.

  13. Signal Intensities in Preoperative MRI Do Not Reflect Proliferative Activity in Meningioma

    Directory of Open Access Journals (Sweden)

    Stefan Schob

    2016-08-01

    Full Text Available BACKGROUND: Identification of high-grade meningiomas in preoperative magnetic resonance imaging (MRI is important for optimized surgical strategy and best possible resection. Numerous studies investigated subjectively determined morphological features as predictors of tumor biology in meningiomas. The aim of this study was to identify the predictive value of more reliable, quantitatively measured signal intensities in MRI for differentiation of high- and low-grade meningiomas and identification of meningiomas with high proliferation rates, respectively. PATIENTS AND METHODS: Sixty-six patients (56 World Health Organization [WHO] grade I, 9 WHO grade II, and 1 WHO grade I were included in the study. Preoperative MRI signal intensities (fluid-attenuated inversion recovery [FLAIR], T1 precontrast, and T1 postcontrast as genuine and normalized values were correlated with Ki-67 expression in tissue sections of resected meningiomas. Differences between the groups (analysis of variance and Spearman rho correlation were computed using SPSS 22. RESULTS: Mean values of genuine signal intensities of meningiomas in FLAIR, T1 native, and T1 postcontrast were 323.9 ± 59, 332.8 ± 67.9, and 768.5 ± 165.3. Mean values of normalized (to the contralateral white matter signal intensities of meningiomas in FLAIR, T1 native, and T1 postcontrast were 1.5 ± 0.3, 0.8 ± 0.1, and 1.9 ± 0.4. There was no significant correlation between MRI signal intensities and WHO grade or Ki-67 expression. Signal intensities did not differ significantly between WHO grade I and II/III meningiomas. Ki-67 expression was significantly increased in high-grade meningiomas compared with low-grade meningiomas (P < 0.01. Objectively measured values of MRI signal intensities (FLAIR, T1 precontrast, and T1 postcontrast enhancement did not distinguish between high-grade and low-grade meningiomas. Furthermore, there was no association between MRI signal intensities and Ki-67 expression

  14. Modality Specific Cerebro-Cerebellar Activations in Verbal Working Memory: An fMRI Study

    Directory of Open Access Journals (Sweden)

    Matthew P. Kirschen

    2010-01-01

    Full Text Available Verbal working memory (VWM engages frontal and temporal/parietal circuits subserving the phonological loop, as well as, superior and inferior cerebellar regions which have projections from these neocortical areas. Different cerebro-cerebellar circuits may be engaged for integrating aurally- and visually-presented information for VWM. The present fMRI study investigated load (2, 4, or 6 letters and modality (auditory and visual dependent cerebro-cerebellar VWM activation using a Sternberg task. FMRI revealed modality-independent activations in left frontal (BA 6/9/44, insular, cingulate (BA 32, and bilateral inferior parietal/supramarginal (BA 40 regions, as well as in bilateral superior (HVI and right inferior (HVIII cerebellar regions. Visual presentation evoked prominent activations in right superior (HVI/CrusI cerebellum, bilateral occipital (BA19 and left parietal (BA7/40 cortex while auditory presentation showed robust activations predominately in bilateral temporal regions (BA21/22. In the cerebellum, we noted a visual to auditory emphasis of function progressing from superior to inferior and from lateral to medial regions. These results extend our previous findings of fMRI activation in cerebro-cerebellar networks during VWM, and demonstrate both modality dependent commonalities and differences in activations with increasing memory load.

  15. Differential Activation Patterns of fMRI in Sleep-Deprived Brain: Restoring Effects of Acupuncture

    Directory of Open Access Journals (Sweden)

    Lei Gao

    2014-01-01

    Full Text Available Previous studies suggested a remediation role of acupuncture in insomnia, and acupuncture also has been used in insomnia empirically and clinically. In this study, we employed fMRI to test the role of acupuncture in sleep deprivation (SD. Sixteen healthy volunteers (8 males were recruited and scheduled for three fMRI scanning procedures, one following the individual’s normal sleep and received acupuncture SP6 (NOR group and the other two after 24 h of total SD with acupuncture on SP6 (SD group or sham (Sham group. The sessions were counterbalanced approximately two weeks apart. Acupuncture stimuli elicited significantly different activation patterns of three groups. In NOR group, the right superior temporal lobe, left inferior parietal lobule, and left postcentral gyrus were activated; in SD group, the anterior cingulate cortex, bilateral insula, left basal ganglia, and thalamus were significantly activated while, in Sham group, the bilateral thalamus and left cerebellum were activated. Different activation patterns suggest a unique role of acupuncture on SP6 in remediation of SD. SP6 elicits greater and anatomically different activations than those of sham stimuli; that is, the salience network, a unique interoceptive autonomic circuit, may indicate the mechanism underlying acupuncture in restoring sleep deprivation.

  16. Modality specific cerebro-cerebellar activations in verbal working memory: an fMRI study.

    Science.gov (United States)

    Kirschen, Matthew P; Chen, S H Annabel; Desmond, John E

    2010-01-01

    Verbal working memory (VWM) engages frontal and temporal/parietal circuits subserving the phonological loop, as well as, superior and inferior cerebellar regions which have projections from these neocortical areas. Different cerebro-cerebellar circuits may be engaged for integrating aurally- and visually-presented information for VWM. The present fMRI study investigated load (2, 4, or 6 letters) and modality (auditory and visual) dependent cerebro-cerebellar VWM activation using a Sternberg task. FMRI revealed modality-independent activations in left frontal (BA 6/9/44), insular, cingulate (BA 32), and bilateral inferior parietal/supramarginal (BA 40) regions, as well as in bilateral superior (HVI) and right inferior (HVIII) cerebellar regions. Visual presentation evoked prominent activations in right superior (HVI/CrusI) cerebellum, bilateral occipital (BA19) and left parietal (BA7/40) cortex while auditory presentation showed robust activations predominantly in bilateral temporal regions (BA21/22). In the cerebellum, we noted a visual to auditory emphasis of function progressing from superior to inferior and from lateral to medial regions. These results extend our previous findings of fMRI activation in cerebro-cerebellar networks during VWM, and demonstrate both modality dependent commonalities and differences in activations with increasing memory load.

  17. Physical Activity Measured With Implanted Devices Predicts Patient Outcome in Chronic Heart Failure

    NARCIS (Netherlands)

    Conraads, Viviane M.; Spruit, Martijn A.; Braunschweig, Frieder; Cowie, Martin R.; Tavazzi, Luigi; Borggrefe, Martin; Hill, Michael R. S.; Jacobs, Sandra; Gerritse, Bart; van Veldhuisen, Dirk J.

    2014-01-01

    Background- Physical activity (PA) predicts cardiovascular mortality in the population at large. Less is known about its prognostic value in patients with chronic heart failure (HF). Methods and Results- Data from 836 patients with implantable cardioverter defibrillator without or with cardiac resyn

  18. Evaluating the Safety Profile of Non-Active Implantable Medical Devices Compared with Medicines

    NARCIS (Netherlands)

    Pane, J. (Josep); P.M. Coloma (Preciosa); K.M.C. Verhamme (Katia); M.C.J.M. Sturkenboom (Miriam); Rebollo, I. (Irene)

    2017-01-01

    textabstractRecent safety issues involving non-active implantable medical devices (NAIMDs) have highlighted the need for better pre-market and post-market evaluation. Some stakeholders have argued that certain features of medicine safety evaluation should also be applied to medical devices. Our obje

  19. [The Vibrant Soundbridge as an active implant in middle ear surgery].

    Science.gov (United States)

    Beleites, T; Bornitz, M; Neudert, M; Zahnert, T

    2014-07-01

    Implantable hearing aids are not only gaining importance for the treatment of sensorineural hearing loss, but also for treatment of mixed hearing loss. The most frequently used active middle ear implant is the Vibrant Soundbridge (VSB) system (Fa. MED-EL, Innsbruck, Österrreich). Following widening of the spectrum of indications for the VBS, various new coupling systems have been established. Based on the literature, available petrosal bone investigations and finite element model (FEM) calculations, this article summarizes the current knowledge concerning mechanical excitation by the VSB. Important concomitant aspects related to coupling, transmission and measurement are also discussed.

  20. Radiochemical neutron activation analysis for certification of ion-implanted phosphorus in silicon.

    Science.gov (United States)

    Paul, Rick L; Simons, David S; Guthrie, William F; Lu, John

    2003-08-15

    A radiochemical neutron activation analysis procedure has been developed, critically evaluated, and shown to have the necessary sensitivity, chemical specificity, matrix independence, and precision to certify phosphorus at ion implantation levels in silicon. 32P, produced by neutron capture of 31P, is chemically separated from the sample matrix and measured using a beta proportional counter. The method is used here to certify the amount of phosphorus in SRM 2133 (Phosphorus Implant in Silicon Depth Profile Standard) as (9.58 +/- 0.16) x 10(14) atoms x cm(-2). A detailed evaluation of uncertainties is given.

  1. Abnormal activation of the motor cortical network in idiopathic scoliosis demonstrated by functional MRI.

    Science.gov (United States)

    Domenech, Julio; García-Martí, G; Martí-Bonmatí, L; Barrios, C; Tormos, J M; Pascual-Leone, A

    2011-07-01

    The aetiology of idiopathic scoliosis (IS) remains unknown, but there is growing support for the possibility of an underlying neurological disorder. Functional magnetic resonance imaging (fMRI) can characterize the abnormal activation of the sensorimotor brain network in movement disorders and could provide further insights into the neuropathogenesis of IS. Twenty subjects were included in the study; 10 adolescents with IS (mean age of 15.2, 8 girls and 2 boys) and 10 age-matched healthy controls. The average Cobb angle of the primary curve in the IS patients was 35° (range 27°-55°). All participants underwent a block-design fMRI experiment in a 1.5-Tesla MRI scanner to explore cortical activation following a simple motor task. Rest periods alternated with activation periods during which participants were required to open and close their hand at an internally paced rate of approximately 1 Hz. Data were analyzed with Statistical Parametric Mapping (SPM5) including age, sex and laterality as nuisance variables to minimise the presence of bias in the results. Compared to controls, IS patients showed significant increases in blood oxygenation level dependent (BOLD) activity in contralateral supplementary motor area when performing the motor task with either hand. No significant differences were observed when testing between groups in the functional activation in the primary motor cortex, premotor cortex and somatosensory cortex. Additionally, the IS group showed a greater interhemispheric asymmetry index than the control group (0.30 vs. 0.13, p motor areas during movement execution in patients with IS. These findings support the hypothesis that a sensorimotor integration disorder underlies the pathogenesis of IS.

  2. Using nonlinear models in fMRI data analysis: model selection and activation detection.

    Science.gov (United States)

    Deneux, Thomas; Faugeras, Olivier

    2006-10-01

    There is an increasing interest in using physiologically plausible models in fMRI analysis. These models do raise new mathematical problems in terms of parameter estimation and interpretation of the measured data. In this paper, we show how to use physiological models to map and analyze brain activity from fMRI data. We describe a maximum likelihood parameter estimation algorithm and a statistical test that allow the following two actions: selecting the most statistically significant hemodynamic model for the measured data and deriving activation maps based on such model. Furthermore, as parameter estimation may leave much incertitude on the exact values of parameters, model identifiability characterization is a particular focus of our work. We applied these methods to different variations of the Balloon Model (Buxton, R.B., Wang, E.C., and Frank, L.R. 1998. Dynamics of blood flow and oxygenation changes during brain activation: the balloon model. Magn. Reson. Med. 39: 855-864; Buxton, R.B., Uludağ, K., Dubowitz, D.J., and Liu, T.T. 2004. Modelling the hemodynamic response to brain activation. NeuroImage 23: 220-233; Friston, K. J., Mechelli, A., Turner, R., and Price, C. J. 2000. Nonlinear responses in fMRI: the balloon model, volterra kernels, and other hemodynamics. NeuroImage 12: 466-477) in a visual perception checkerboard experiment. Our model selection proved that hemodynamic models better explain the BOLD response than linear convolution, in particular because they are able to capture some features like poststimulus undershoot or nonlinear effects. On the other hand, nonlinear and linear models are comparable when signals get noisier, which explains that activation maps obtained in both frameworks are comparable. The tools we have developed prove that statistical inference methods used in the framework of the General Linear Model might be generalized to nonlinear models.

  3. Abnormal rate of intraoperative and postoperative implant positioning outliers using "MRI-based patient-specific" compared to "computer assisted" instrumentation in total knee replacement.

    Science.gov (United States)

    Ollivier, M; Tribot-Laspiere, Q; Amzallag, J; Boisrenoult, P; Pujol, N; Beaufils, P

    2016-11-01

    The aim of this study was to analyze first intraoperative alignment and reason to abandon the use of patient-specific instrumentation using intraoperative CAS measurement, secondly assess by postoperative CT analysis if CI, based on preoperative 3D-MRI data, improved postoperative component positioning (including femoral rotation) and lower limb alignment as compared with results obtained with CAS. In this randomized controlled trial, 80 consecutive patients scheduled to undergo TKA were enrolled. Eligible knees were randomized to the group of PSI-TKAs (n = 40) or to the group of CAS-TKAs (n = 40). In the CAS group, CAS determined and controlled cutting block positioning in each plane. In the PSI group, CAS allowed to measure adequacy of intraoperative alignment including femoral component rotation. At 3 months after surgery, implants position were measured and analyzed with full-weight bearing plain radiographs and CT scan. Intraoperatively, there was a significant difference concerning Sagittal Femoral mechanical, Frontal tibial mechanical angle and tibial slope between the two groups (respectively p = 0.01, p = 0.02, p = 0.046). Custom instrumentation was abandoned intraoperatively in seven knees (17.5 %). Abnormal tibial cuts were responsible of the abandon in three out of seven cases, femoral cut in 1/7 and dual abnormalities in 3/7. Postoperatively, tibial slope outliers percentage was higher in the patient specific instrumentation group with six patients (18.18 %) versus one patient (2.5 %) in the CAS group (p = 0.041). Patient specific instrumentation was associated with an important number of hazardous cut and a higher rate of outliers in our series and thus should be used with caution as related to. This study is the first to our acknowledgement to compare intra-operative ancillary and implant positioning of PSI-TKA and CAS-TKA. High rate of malposition are sustained by our findings, as such PSI-TKA should be used with caution, by surgeons

  4. Impact of Ion Implantation on Licorice (Glycyrrhiza uralensis Fisch) Growth and Antioxidant Activity Under Drought Stress

    Science.gov (United States)

    Liu, Jingnan; Tong, Liping; Shen, Tongwei; Li, Jie; Wu, Lijun; Yu, Zengliang

    2007-06-01

    Low energy ion beams are known to have stimulation effects on plant generation and to improve plants' intrinsic quality. In the present study, the growth and physiological index of licorice implanted with 0, 8, 10, 12 and 14× (2.6×1015) ions/cm2 were investigated under well-watered and drought-stress conditions. The results showed that a proper dose of ion implantation was particularly efficient in stimulating the licorice growth and improving the plant biomass significantly in both the well-watered and drought-stress conditions. The physiological results of licorice measured by leaf water potential, lipid oxidation, soluble protein and antioxidant system showed a significant correlation between ion implantation and water regime except for leaf water potential. Therefore, the study indicated that ion implantation can enhance licorice's drought tolerance by increasing the activity of superoxide dismutase (SOD), catalase (CAT) and DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging ability to lower oxidative damage to lipids in plants. Ion beam implantation, therefore, provides an alternative method to enhance licorice drought tolerance.

  5. Impact of Ion Implantation on Licorice ( Glycyrrhiza uralensis Fisch ) Growth and Antioxidant Activity Under Drought Stress

    Institute of Scientific and Technical Information of China (English)

    LIU Jingnan; TONG Liping; SHEN Tongwei; LI Jie; WU Lijun; YU Zengliang

    2007-01-01

    Low energy ion beams are known to have stimulation effects on plant generation and to improve plants' intrinsic quality. In the present study, the growth and physiological index of licorice implanted with 0, 8, 10, 12 and 14× (2.6×l015) ions/cm2 were investigated under well-watered and drought-stress conditions. The results showed that a proper dose of ion implantation was particularly efficient in stimulating the licorice growth and improving the plant biomass significantly in both the well-watered and drought-stress conditions. The physiological results of licorice measured by leaf water potential, lipid oxidation, soluble protein and antioxidant system showed a significant correlation between ion implantation and water regime except for leaf water potential. Therefore, the study indicated that ion implantation can enhance licorice's drought tolerance by increasing the activity of superoxide dismutase (SOD), catalase (CAT) and DPPH (l,l-diphenyl-2-picrylhydrazyl) radical scavenging ability to lower oxidative damage to lipids in plants. Ion beam implantation, therefore, provides an alternative method to enhance licorice drought tolerance.

  6. Algorithm for quantifying advanced carotid artery atherosclerosis in humans using MRI and active contours

    Science.gov (United States)

    Adams, Gareth; Vick, G. W., III; Bordelon, Cassius; Insull, William; Morrisett, Joel

    2002-05-01

    A new algorithm for measuring carotid artery volumes and estimating atherosclerotic plaque volumes from MRI images has been developed and validated using pressure-perfusion-fixed cadaveric carotid arteries. Our method uses an active contour algorithm with the generalized gradient vector field force as the external force to localize the boundaries of the artery on each MRI cross-section. Plaque volume is estimated by an automated algorithm based on estimating the normal wall thickness for each branch of the carotid. Triplicate volume measurements were performed by a single observer on thirty-eight pairs of cadaveric carotid arteries. The coefficient of variance (COV) was used to quantify measurement reproducibility. Aggregate volumes were computed for nine contiguous slices bounding the carotid bifurcation. The median (mean +/- SD) COV for the 76 aggregate arterial volumes was 0.93% (1.47% +/- 1.52%) for the lumen volume, 0.95% (1.06% +/- 0.67%) for the total artery volume, and 4.69% (5.39% +/- 3.97%) for the plaque volume. These results indicate that our algorithm provides repeatable measures of arterial volumes and a repeatable estimate of plaque volume of cadaveric carotid specimens through analysis of MRI images. The algorithm also significantly decreases the amount of time necessary to generate these measurements.

  7. Active control of the spatial MRI phase distribution with optimal control theory

    Science.gov (United States)

    Lefebvre, Pauline M.; Van Reeth, Eric; Ratiney, Hélène; Beuf, Olivier; Brusseau, Elisabeth; Lambert, Simon A.; Glaser, Steffen J.; Sugny, Dominique; Grenier, Denis; Tse Ve Koon, Kevin

    2017-08-01

    This paper investigates the use of Optimal Control (OC) theory to design Radio-Frequency (RF) pulses that actively control the spatial distribution of the MRI magnetization phase. The RF pulses are generated through the application of the Pontryagin Maximum Principle and optimized so that the resulting transverse magnetization reproduces various non-trivial and spatial phase patterns. Two different phase patterns are defined and the resulting optimal pulses are tested both numerically with the ODIN MRI simulator and experimentally with an agar gel phantom on a 4.7 T small-animal MR scanner. Phase images obtained in simulations and experiments are both consistent with the defined phase patterns. A practical application of phase control with OC-designed pulses is also presented, with the generation of RF pulses adapted for a Magnetic Resonance Elastography experiment. This study demonstrates the possibility to use OC-designed RF pulses to encode information in the magnetization phase and could have applications in MRI sequences using phase images.

  8. Pain facilitation brain regions activated by nalbuphine are revealed by pharmacological fMRI.

    Directory of Open Access Journals (Sweden)

    Robert Gear

    Full Text Available Nalbuphine, an agonist-antagonist kappa-opioid, produces brief analgesia followed by enhanced pain/hyperalgesia in male postsurgical patients. However, it produces profound analgesia without pain enhancement when co-administration with low dose naloxone. To examine the effect of nalbuphine or nalbuphine plus naloxone on activity in brain regions that may explain these differences, we employed pharmacological magnetic resonance imaging (phMRI in a double blind cross-over study with 13 healthy male volunteers. In separate imaging sessions subjects were administered nalbuphine (5 mg/70 kg preceded by either saline (Sal-Nalb or naloxone 0.4 mg (Nalox-Nalb. Blood oxygen level-dependent (BOLD activation maps followed by contrast and connectivity analyses revealed marked differences. Sal-Nalb produced significantly increased activity in 60 brain regions and decreased activity in 9; in contrast, Nalox-Nalb activated only 14 regions and deactivated only 3. Nalbuphine, like morphine in a previous study, attenuated activity in the inferior orbital cortex, and, like noxious stimulation, increased activity in temporal cortex, insula, pulvinar, caudate, and pons. Co-administration/pretreatment of naloxone selectively blocked activity in pulvinar, pons and posterior insula. Nalbuphine induced functional connectivity between caudate and regions in the frontal, occipital, temporal, insular, middle cingulate cortices, and putamen; naloxone co-admistration reduced all connectivity to non-significant levels, and, like phMRI measures of morphine, increased activation in other areas (e.g., putamen. Naloxone pretreatment to nalbuphine produced changes in brain activity possess characteristics of both analgesia and algesia; naloxone selectively blocks activity in areas associated with algesia. Given these findings, we suggest that nalbuphine interacts with a pain salience system, which can modulate perceived pain intensity.

  9. The effects of skin tone on race-related amygdala activity: an fMRI investigation.

    Science.gov (United States)

    Ronquillo, Jaclyn; Denson, Thomas F; Lickel, Brian; Lu, Zhong-Lin; Nandy, Anirvan; Maddox, Keith B

    2007-03-01

    Previous work has shown differential amygdala response to African-American faces by Caucasian individuals. Furthermore, behavioral studies have demonstrated the existence of skin tone bias, the tendency to prefer light skin to dark skin. In the present study, we used functional magnetic resonance imaging (fMRI) to investigate whether skin tone bias moderates differential race-related amygdala activity. Eleven White participants viewed photographs of unfamiliar Black and White faces with varied skin tone (light, dark). Replicating past research, greater amygdala activity was observed for Black faces than White faces. Furthermore, dark-skinned targets elicited more amygdala activity than light-skinned targets. However, these results were qualified by a significant interaction between race and skin tone, such that amygdala activity was observed at equivalent levels for light- and dark-skinned Black targets, but dark-skinned White targets elicited greater amygdala activity than light-skinned White targets.

  10. Kinetic Monte Carlo simulations of boron activation in implanted Si under laser thermal annealing

    Science.gov (United States)

    Fisicaro, Giuseppe; Pelaz, Lourdes; Aboy, Maria; Lopez, Pedro; Italia, Markus; Huet, Karim; Cristiano, Filadelfo; Essa, Zahi; Yang, Qui; Bedel-Pereira, Elena; Quillec, Maurice; La Magna, Antonino

    2014-02-01

    We investigate the correlation between dopant activation and damage evolution in boron-implanted silicon under excimer laser irradiation. The dopant activation efficiency in the solid phase was measured under a wide range of irradiation conditions and simulated using coupled phase-field and kinetic Monte Carlo models. With the inclusion of dopant atoms, the presented code extends the capabilities of a previous version, allowing its definitive validation by means of detailed comparisons with experimental data. The stochastic method predicts the post-implant kinetics of the defect-dopant system in the far-from-equilibrium conditions caused by laser irradiation. The simulations explain the dopant activation dynamics and demonstrate that the competitive dopant-defect kinetics during the first laser annealing treatment dominates the activation phenomenon, stabilizing the system against additional laser irradiation steps.

  11. Altered cortical activation during action observation in amyotrophic lateral sclerosis patients: a parametric functional MRI study

    Energy Technology Data Exchange (ETDEWEB)

    Li, Haiqing; Li, Yuxin; Yin, Bo; Tang, Weijun; Yu, Xiangrong; Geng, Daoying [Huashan Hospital, Department of Radiology, Fudan University, Shanghai (China); Chen, Yan [Fudan University, Department of Neurology, Huashan Hospital, Shanghai (China); Huang, Weiyuan [People' s Hospital of Hainan Province, Department of Radiology, Haikou, Hainan Province (China); Zhang, Biyun [Nanjing University of Traditional Chinese Medicine, Department of radiotherapy, Affiliated Jiangsu Province Hospital of Traditional Chinese Medicine, Nanjing (China)

    2015-09-15

    To investigate functional cerebral abnormalities in patients with amyotrophic lateral sclerosis (ALS) using functional magnetic resonance imaging (fMRI) during action observation. Thirty patients with ALS and 30 matched healthy controls underwent fMRI with an experimental paradigm while observing a video of repetitive flexion-extension of the fingers at three frequency levels or three complexity levels, alternated with periods of a static hand. A parametric analysis was applied to determine the effects of each of the two factors. Action observation activated similar neural networks as the research on execution of action in the ALS patients and healthy subjects in several brain regions related to the mirror-neuron system (MNS). In the ALS patients, in particular, the dorsal lateral premotor cortex (dPMC), inferior parietal gyrus (IPG), and SMA, were more activated compared with the activation in the controls. Increased activation within the primary motor cortex (M1), dPMC, inferior frontal gyrus (IFG), and superior parietal gyrus (SPG) mainly correlated with hand movement frequency/complexity in the videos in the patients compared with controls. The findings indicated an ongoing compensatory process occurring within the higher order motor-processing system of ALS patients, likely to overcome the loss of function. (orig.)

  12. Differentiating maturational and training influences on fMRI activation during music processing.

    Science.gov (United States)

    Ellis, Robert J; Norton, Andrea C; Overy, Katie; Winner, Ellen; Alsop, David C; Schlaug, Gottfried

    2012-04-15

    Two major influences on how the brain processes music are maturational development and active musical training. Previous functional neuroimaging studies investigating music processing have typically focused on either categorical differences between "musicians versus nonmusicians" or "children versus adults." In the present study, we explored a cross-sectional data set (n=84) using multiple linear regression to isolate the performance-independent effects of age (5 to 33 years) and cumulative duration of musical training (0 to 21,000 practice hours) on fMRI activation similarities and differences between melodic discrimination (MD) and rhythmic discrimination (RD). Age-related effects common to MD and RD were present in three left hemisphere regions: temporofrontal junction, ventral premotor cortex, and the inferior part of the intraparietal sulcus, regions involved in active attending to auditory rhythms, sensorimotor integration, and working memory transformations of pitch and rhythmic patterns. By contrast, training-related effects common to MD and RD were localized to the posterior portion of the left superior temporal gyrus/planum temporale, an area implicated in spectrotemporal pattern matching and auditory-motor coordinate transformations. A single cluster in right superior temporal gyrus showed significantly greater activation during MD than RD. This is the first fMRI which has distinguished maturational from training effects during music processing. Copyright © 2012 Elsevier Inc. All rights reserved.

  13. Correlations between histology and neuronal activity recorded by microelectrodes implanted chronically in the cerebral cortex

    Science.gov (United States)

    McCreery, Douglas; Cogan, Stuart; Kane, Sheryl; Pikov, Victor

    2016-06-01

    Objective. To quantify relations between the neuronal activity recorded with chronically-implanted intracortical microelectrodes and the histology of the surrounding tissue, using radial distance from the tip sites and time after array implantation as parameters. Approach. ‘Utah’-type intracortical microelectrode arrays were implanted into cats’ sensorimotor cortex for 275-364 days. The brain tissue around the implants was immuno-stained for the neuronal marker NeuN and for the astrocyte marker GFAP. Pearson’s product-moment correlations were used to quantify the relations between these markers and the amplitudes of the recorded neuronal action potentials (APs) and their signal-to-noise ratios (S/N). Main results. S/N was more stable over post-implant time than was AP amplitude, but its increased correlation with neuronal density after many months indicates ongoing loss of neurons around the microelectrodes. S/N was correlated with neuron density out to at least 140 μm from the microelectrodes, while AP amplitude was correlated with neuron density and GFAP density within ˜80 μm. Correlations between AP amplitude and histology markers (GFAP and NeuN density) were strongest immediately after implantation, while correlation between the neuron density and S/N was strongest near the time the animals were sacrificed. Unlike AP amplitude, there was no significant correlation between S/N and density of GFAP around the tip sites. Significance. Our findings indicate an evolving interaction between changes in the tissue surrounding the microelectrodes and the microelectrode’s electrical properties. Ongoing loss of neurons around recording microelectrodes, and the interactions between their delayed electrical deterioration and early tissue scarring around the tips appear to pose the greatest threats to the microelectrodes’ long-term functionality.

  14. Evolution of impedance field telemetry after one day of activation in cochlear implant recipients

    Science.gov (United States)

    Tsai, Chia-Mi; Chen, Hsing-Yi; Tung, Tao-Hsin; Li, Lieber Po-Hung

    2017-01-01

    Objectives Changes in impedance between 24 hours and one month after cochlear implantation have never been explored due to the inability to switch on within one day. This study examined the effect of early activation (within 24 hours) on the evolution of electrode impedance with the aim of providing information on the tissue-to-electrode interface when electrical stimulation was commenced one day post implantation. Methods We performed a retrospective review at a single institution. Patients who received a Nucleus 24RECA implant system (Cochlear, Sydney, Australia) and underwent initial switch-on within 24 hours postoperatively were included. Impedance measurements were obtained intraoperatively and postoperatively at 1 day, 1 week, 4 weeks, and 8 weeks. Results A significant drop in impedance was noted 1 day after an initial activation within 24 hours followed by a significant rise in impedance in all channels until 1 week, after which the impedance behaved differently in different segments. Basal and mid-portion electrodes revealed a slight increase while apical electrodes showed a slight decrease in impedance from 1 week to 8 weeks postoperatively. Impedance was relatively stable 4 weeks after surgery. Conclusions This is the first study to report the evolution of impedance in all channels between initial mapping 1 day and 1 month after cochlear implantation. The underlying mechanism for the differences in behavior between different segments of the electrode may be associated with the combined effect of dynamics among the interplay of cell cover formation, electrical stimulation, and fibrotic reaction. PMID:28264044

  15. Active implantable medical device EMI assessment for wireless power transfer operating in LF and HF bands

    Science.gov (United States)

    Hikage, Takashi; Nojima, Toshio; Fujimoto, Hiroshi

    2016-06-01

    The electromagnetic interference (EMI) imposed on active implantable medical devices by wireless power transfer systems (WPTSs) is discussed based upon results of in vitro experiments. The purpose of this study is to present comprehensive EMI test results gathered from implantable-cardiac pacemakers and implantable cardioverter defibrillators exposed to the electromagnetic field generated by several WPTSs operating in low-frequency (70 kHz-460 kHz) and high-frequency (6.78 MHz) bands. The constructed in vitro experimental test system based upon an Irnich’s flat torso phantom was applied. EMI test experiments are conducted on 14 types of WPTSs including Qi-compliant system and EV-charging WPT system mounted on current production EVs. In addition, a numerical simulation model for active implantable medical device (AIMD) EMI estimation based on the experimental test system is newly proposed. The experimental results demonstrate the risk of WPTSs emitting intermittent signal to affect the correct behavior of AIMDs when operating at very short distances. The proposed numerical simulation model is applicable to obtain basically the EMI characteristics of various types of WPTSs.

  16. Estimation of the neuronal activation using fMRI data: An observer-based approach

    KAUST Repository

    Laleg-Kirati, Taous-Meriem

    2013-06-01

    This paper deals with the estimation of the neuronal activation and some unmeasured physiological information using the Blood Oxygenation Level Dependent (BOLD) signal measured using functional Magnetic Resonance Imaging (fMRI). We propose to use an observer-based approach applied to the balloon hemodynamic model. The latter describes the relation between the neural activity and the BOLD signal. The balloon model can be expressed in a nonlinear state-space representation where the states, the parameters and the input (neuronal activation), are unknown. This study focuses only on the estimation of the hidden states and the neuronal activation. The model is first linearized around the equilibrium and an observer is applied to this linearized version. Numerical results performed on synthetic data are presented.

  17. Activated region fitting: a robust high-power method for fMRI analysis using parameterized regions of activation.

    Science.gov (United States)

    Weeda, Wouter D; Waldorp, Lourens J; Christoffels, Ingrid; Huizenga, Hilde M

    2009-08-01

    An important issue in the analysis of fMRI is how to account for the spatial smoothness of activated regions. In this article a method is proposed to accomplish this by modeling activated regions with Gaussian shapes. Hypothesis tests on the location, spatial extent, and amplitude of these regions are performed instead of hypothesis tests of individual voxels. This increases power and eases interpretation. Simulation studies show robust hypothesis tests under misspecification of the shape model, and increased power over standard techniques especially at low signal-to-noise ratios. An application to real single-subject data also indicates that the method has increased power over standard methods.

  18. Functional MRI activation of primary and secondary motor areas in healthy subjects

    Institute of Scientific and Technical Information of China (English)

    Donghai Li; Honghan Gong; Xiangzuo Xiao; Jinhua Wan

    2008-01-01

    BACKGROUND:Functional MRI(fMRI)demonstrates the localization of hand representation in the motor cortex,thereby providing feasible noninvasive mapping of functional activities in the human brain.OBJECTIVE:To observe cortical activation within different cortical motor regions during repetitive hand movements in healthy subjects through the use of fMRI.DESIGN:An observational study,with each subject acting as his own control.SETTING:Department of Radiology,the First Affiliated Hospital of Nanchang University.PARTICIPANTS:Seven healthy volunteers,4 males and 3/females,aged 19 to 38 years,participated in the study.All subjects were right-handed,with no neurological or psychological disorders.Informed written consent was obtained from all subjects,and the study was approved by the Institutional Review Board of the First Affiliated Hospital of Nanchang University.METHODS:The study was performed at the Department of Radiology between June-August 2005.A 1.5 Tesla Siemens MRI scanner(Symphony,Germany)was used to acquire Tl-weighted structural images,which were oriented parallel to the line running through the anterior and the posterior commissures.Subjects were instructed on a task and were allowed to practice briefly prior to the imaging procedure.The motor activation task consisted of the right hand performing a clenching movement.The T1-W images were acquired from six alternating epochs of rest and activation from all seven healthy subjects.Data were collected with echoplanar imaging of brain oxygen level dependent(BOLD)sequence.Each series comprised six cycles of task pertormance(30 seconds),alternating with rest(30 seconds) periods,and 3-second time intervals.The differences between active and baseline fMRI imaging were calculated using the student t-test.Differential maps were overlaid on the high resolution T1-W structural image for neuroanatomical correlation of activation areas.MAIN OUTCOME MEASURES:The omega-shaped hand knobs were recognized on T1-W structural

  19. Activation of dorsolateral prefrontal cortex in a dual neuropsychological screening test: an fMRI approach.

    Science.gov (United States)

    Tachibana, Atsumichi; Noah, J Adam; Bronner, Shaw; Ono, Yumie; Hirano, Yoshiyuki; Niwa, Masami; Watanabe, Kazuko; Onozuka, Minoru

    2012-05-28

    The Kana Pick-out Test (KPT), which uses Kana or Japanese symbols that represent syllables, requires parallel processing of discrete (pick-out) and continuous (reading) dual tasks. As a dual task, the KPT is thought to test working memory and executive function, particularly in the prefrontal cortex (PFC), and is widely used in Japan as a clinical screen for dementia. Nevertheless, there has been little neurological investigation into PFC activity during this test. We used functional magnetic resonance imaging (fMRI) to evaluate changes in the blood oxygenation level-dependent (BOLD) signal in young healthy adults during performance of a computerized KPT dual task (comprised of reading comprehension and picking out vowels) and compared it to its single task components (reading or vowel pick-out alone). Behavioral performance of the KPT degraded compared to its single task components. Performance of the KPT markedly increased BOLD signal intensity in the PFC, and also activated sensorimotor, parietal association, and visual cortex areas. In conjunction analyses, bilateral BOLD signal in the dorsolateral PFC (Brodmann's areas 45, 46) was present only in the KPT. Our results support the central bottleneck theory and suggest that the dorsolateral PFC is an important mediator of neural activity for both short-term storage and executive processes. Quantitative evaluation of the KPT with fMRI in healthy adults is the first step towards understanding the effects of aging or cognitive impairment on KPT performance.

  20. Activation of dorsolateral prefrontal cortex in a dual neuropsychological screening test: An fMRI approach

    Directory of Open Access Journals (Sweden)

    Tachibana Atsumichi

    2012-05-01

    Full Text Available Abstract Background The Kana Pick-out Test (KPT, which uses Kana or Japanese symbols that represent syllables, requires parallel processing of discrete (pick-out and continuous (reading dual tasks. As a dual task, the KPT is thought to test working memory and executive function, particularly in the prefrontal cortex (PFC, and is widely used in Japan as a clinical screen for dementia. Nevertheless, there has been little neurological investigation into PFC activity during this test. Methods We used functional magnetic resonance imaging (fMRI to evaluate changes in the blood oxygenation level-dependent (BOLD signal in young healthy adults during performance of a computerized KPT dual task (comprised of reading comprehension and picking out vowels and compared it to its single task components (reading or vowel pick-out alone. Results Behavioral performance of the KPT degraded compared to its single task components. Performance of the KPT markedly increased BOLD signal intensity in the PFC, and also activated sensorimotor, parietal association, and visual cortex areas. In conjunction analyses, bilateral BOLD signal in the dorsolateral PFC (Brodmann's areas 45, 46 was present only in the KPT. Conclusions Our results support the central bottleneck theory and suggest that the dorsolateral PFC is an important mediator of neural activity for both short-term storage and executive processes. Quantitative evaluation of the KPT with fMRI in healthy adults is the first step towards understanding the effects of aging or cognitive impairment on KPT performance.

  1. Enhanced electrical activation in In-implanted Ge by C co-doping

    Energy Technology Data Exchange (ETDEWEB)

    Feng, R., E-mail: ruixing.feng@anu.edu.au; Kremer, F.; Mirzaei, S.; Medling, S. A.; Ridgway, M. C. [Department of Electronic Materials Engineering, Australian National University, Canberra ACT 0200 (Australia); Sprouster, D. J. [Nuclear Science and Technology Department, Brookhaven National Laboratory, Upton, New York 11973 (United States); Decoster, S.; Pereira, L. M. C. [KU Leuven, Instituut voor Kern-en Stralingsfysica, 3001 Leuven (Belgium); Glover, C. J. [Australian Synchrotron, 800 Blackburn Road, Clayton, Victoria 3168 (Australia); Russo, S. P. [Applied Physics, School Applied Sciences, RMIT University, Melbourne 3001 (Australia)

    2015-11-23

    At high dopant concentrations in Ge, electrically activating all implanted dopants is a major obstacle in the fulfillment of high-performance Ge-channel complementary metal oxide semiconductor devices. In this letter, we demonstrate a significant increase in the electrically-active dopant fraction in In-implanted Ge by co-doping with the isovalent element C. Electrical measurements have been correlated with x-ray absorption spectroscopy and transmission electron microscopy results in addition to density functional theory simulations. With C + In co-doping, the electrically active fraction was doubled and tripled at In concentrations of 0.2 and 0.7 at. %, respectively. This marked improvement was the result of C-In pair formation such that In-induced strain in the Ge lattice was reduced while the precipitation of In and the formation of In-V clusters were both suppressed.

  2. Surgical factors in pediatric cochlear implantation and their early effects on electrode activation and functional outcomes.

    Science.gov (United States)

    Francis, Howard W; Buchman, Craig A; Visaya, Jiovani M; Wang, Nae-Yuh; Zwolan, Teresa A; Fink, Nancy E; Niparko, John K

    2008-06-01

    To assess the impact of surgical factors on electrode status and early communication outcomes in young children in the first 2 years of cochlear implantation. Prospective multicenter cohort study. Six tertiary referral centers. Children 5 years or younger before implantation with normal nonverbal intelligence. Cochlear implant operations in 209 ears of 188 children. Percent active channels, auditory behavior as measured by the Infant Toddler Meaningful Auditory Integration Scale/Meaningful Auditory Integration Scale and Reynell receptive language scores. Stable insertion of the full electrode array was accomplished in 96.2% of ears. At least 75% of electrode channels were active in 88% of ears. Electrode deactivation had a significant negative effect on Infant Toddler Meaningful Auditory Integration Scale/Meaningful Auditory Integration Scale scores at 24 months but no effect on receptive language scores. Significantly fewer active electrodes were associated with a history of meningitis. Surgical complications requiring additional hospitalization and/or revision surgery occurred in 6.7% of patients but had no measurable effect on the development of auditory behavior within the first 2 years. Negative, although insignificant, associations were observed between the need for perioperative revision of the device and 1) the percent of active electrodes and 2) the receptive language level at 2-year follow-up. Activation of the entire electrode array is associated with better early auditory outcomes. Decrements in the number of active electrodes and lower gains of receptive language after manipulation of the newly implanted device were not statistically significant but may be clinically relevant, underscoring the importance of surgical technique and the effective placement of the electrode array.

  3. Temperature Activated Diffusion of Radicals through Ion Implanted Polymers

    DEFF Research Database (Denmark)

    Wakelin, Edgar A.; Davies, Michael J.; Bilek, Marcela M. M.

    2015-01-01

    and controlling the diffusion of radicals through this layer will enable efficient optimization of this technique. We develop a model based on site to site diffusion according to Fick's second law with temperature activation according to the Arrhenius relation. Using our model, the Arrhenius exponential prefactor...

  4. Effect of slice orientation on reproducibility of fMRI motor activation at 3 Tesla.

    Science.gov (United States)

    Gustard, S; Fadili, J; Williams, E J; Hall, L D; Carpenter, T A; Brett, M; Bullmore, E T

    2001-12-01

    The effect of slice orientation on reproducibility and sensitivity of 3T fMRI activation using a motor task has been investigated in six normal volunteers. Four slice orientations were used; axial, oblique axial, coronal and sagittal. We applied analysis of variance (ANOVA) to suprathreshold voxel statistics to quantify variability in activation between orientations and between subjects. We also assessed signal detection accuracy in voxels across the whole brain by using a finite mixture model to fit receiver operating characteristic (ROC) curves to the data. Preliminary findings suggest that suprathreshold cluster characteristics demonstrate high motor reproducibility across subjects and orientations, although a significant difference between slice orientations in number of activated voxels was demonstrated in left motor cortex but not cerebellum. Subtle inter-orientation differences are highlighted in the ROC analyses, which are not obvious by ANOVA; the oblique axial slice orientation offers the highest signal detection accuracy, whereas coronal slices give the lowest.

  5. Posterior midline activation during symptom provocation in acute stress disorder: An fMRI study

    Directory of Open Access Journals (Sweden)

    Jan Christopher Cwik

    2014-05-01

    Full Text Available Functional imaging studies of patients with Posttraumatic Stress Disorder showed wide-spread activation of mid-line cortical areas during symptom provocation i.e., exposure to trauma-related cues. The present study aimed at investigating neural activation during exposure to trauma-related pictures in patients with Acute Stress Disorder (ASD shortly after the traumatic event. Nineteen ASD patients and 19 healthy control participants were presented with individualized pictures of the traumatic event and emotionally neutral control pictures during the acquisition of whole-brain data with a 3-T fMRI scanner. Compared to the control group and to control pictures, ASD patients showed significant activation in mid-line cortical areas in response to trauma-related pictures including precuneus, cuneus, postcentral gyrus and pre-supplementary motor area. The results suggest that the trauma-related pictures evoke emotionally salient self-referential processing in ASD patients.

  6. RESOLUTE PET/MRI Attenuation Correction for O-(2-(18)F-fluoroethyl)-L-tyrosine (FET) in Brain Tumor Patients with Metal Implants.

    Science.gov (United States)

    Ladefoged, Claes N; Andersen, Flemming L; Kjær, Andreas; Højgaard, Liselotte; Law, Ian

    2017-01-01

    Aim: Positron emission tomography (PET) imaging is a useful tool for assisting in correct differentiation of tumor progression from reactive changes, and the radiolabeled amino acid analog tracer O-(2-(18)F-fluoroethyl)-L-tyrosine (FET)-PET is amongst the most frequently used. The FET-PET images need to be quantitatively correct in order to be used clinically, which require accurate attenuation correction (AC) in PET/MRI. The aim of this study was to evaluate the use of the subject-specific MR-derived AC method RESOLUTE in post-operative brain tumor patients. Methods: We analyzed 51 post-operative brain tumor patients (68 examinations, 200 MBq [18F]-FET) investigated in a PET/MRI scanner. MR-AC maps were acquired using: (1) the Dixon water fat separation sequence, (2) the ultra short echo time (UTE) sequences, (3) calculated using our new RESOLUTE methodology, and (4) a same day low-dose CT used as reference "gold standard." For each subject and each AC method the tumor was delineated by isocontouring tracer uptake above a tumor(T)-to-brain background (B) activity ratio of 1.6. We measured B, tumor mean and maximal activity (TMEAN, TMAX), biological tumor volume (BTV), and calculated the clinical metrics TMEAN/B and TMAX/B. Results: When using RESOLUTE 5/68 studies did not meet our predefined acceptance criteria of TMAX/B difference to CT-AC PET metrics. Conclusions: Overall, we found RESOLUTE to be the AC method that most robustly reproduced the CT-AC clinical metrics per se, during follow-up, and when interpreted into defined clinical use cut-off criteria and into the patient history. RESOLUTE is especially suitable for brain tumor patients, as these often present with distorted anatomy where other methods based on atlas/template information might fail.

  7. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... it may cause some medical devices to malfunction. Most orthopedic implants pose no risk, but you should ... copied to a CD. Currently, MRI is the most sensitive imaging test of the head (particularly the ...

  8. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... may cause some medical devices to malfunction. Most orthopedic implants pose no risk, but you should always ... metal objects. In general, metal objects used in orthopedic surgery pose no risk during MRI. However, a ...

  9. Magnetic Resonance Imaging (MRI) - Spine

    Science.gov (United States)

    ... their nature and the strength of the MRI magnet. Many implanted devices will have a pamphlet explaining ... large cylinder-shaped tube surrounded by a circular magnet. You will lie on a moveable examination table ...

  10. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... multiple sclerosis disorders of the eye and inner ear disorders of pituitary gland vascular problems, such as ... should not enter the MRI scanning area: cochlear (ear) implant some types of clips used for brain ...

  11. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... is not harmful, but it may cause some medical devices to malfunction. Most orthopedic implants pose no ... Head? Magnetic resonance imaging (MRI) is a noninvasive medical test that physicians use to diagnose medical conditions. ...

  12. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... and should not enter the MRI scanning area: cochlear (ear) implant some types of clips used for ... follow-up exam is done because a potential abnormality needs further evaluation with additional views or a ...

  13. Grading of Crohn's disease activity using CT, MRI, US and scintigraphy: a meta-analysis

    Energy Technology Data Exchange (ETDEWEB)

    Puylaert, C.A.J.; Tielbeek, J.A.W.; Bipat, S.; Stoker, J. [University of Amsterdam, Academic Medical Center, Department of Radiology, Amsterdam (Netherlands)

    2015-11-15

    To assess the grading of Crohn's disease activity using CT, MRI, US and scintigraphy. MEDLINE, EMBASE and Cochrane databases were searched (January 1983-March 2014) for studies evaluating CT, MRI, US and scintigraphy in grading Crohn's disease activity compared to endoscopy, biopsies or intraoperative findings. Two independent reviewers assessed the data. Three-by-three tables (none, mild, frank disease) were constructed for all studies, and estimates of accurate, over- and under-grading were calculated/summarized by fixed or random effects models. Our search yielded 9356 articles, 19 of which were included. Per-patient data showed accurate grading values for CT, MRI, US and scintigraphy of 86 % (95 % CI: 75-93 %), 84 % (95 % CI: 67-93 %), 44 % (95 % CI: 28-61 %) and 40 % (95 % CI: 16-70 %), respectively. In the per-patient analysis, CT and MRI showed similar accurate grading estimates (P = 0.8). Per-segment data showed accurate grading values for CT and scintigraphy of 87 % (95 % CI: 77-93 %) and 86 % (95 % CI: 80-91 %), respectively. MRI and US showed grading accuracies of 67-82 % and 56-75 %, respectively. CT and MRI showed comparable high accurate grading estimates in the per-patient analysis. Results for US and scintigraphy were inconsistent, and limited data were available. (orig.)

  14. EEG/fMRI study of ictal and interictal epileptic activity: methodological issues and future perspectives in clinical practice.

    Science.gov (United States)

    Di Bonaventura, Carlo; Vaudano, Anna E; Carnì, Marco; Pantano, Patrizia; Nucciarelli, Valter; Garreffa, Girolamo; Maraviglia, Bruno; Prencipe, Massimiliano; Bozzao, Luigi; Manfredi, Mario; Giallonardo, Anna T

    2006-01-01

    Electroencephalography/functional magnetic resonance imaging (EEG/fMRI) has been proposed recently as a tool to study electrophysiological activity and, consequently, detect brain regions activated during epileptiform EEG abnormalities. The purpose of the study was to review our two-year experience with studying ictal and interictal activities in patients with epilepsy. Using EEG/fMRI, we studied hemodynamic changes associated with ictal and interictal EEG abnormalities in 43 patients with partial (31 cases) or generalized (12 cases) epilepsy. Using two different paradigms (block design and event-related design), we studied several forms of EEG activity consisting of (i) interictal abnormalities constantly elicitable by specific stimulation (8 cases); (ii) focal and generalized interictal activity, such as focal spikes or typical and atypical generalized spike-and-wave discharges (18 cases); and (iii) focal and generalized ictal electro-clinical activity, such as tonic seizures or pseudo-absences in frontal lobe epilepsy, typical absences in idiopathic generalized epilepsy, complex partial seizures in temporal lobe epilepsy, and perisylvian seizures in special syndromes (17 patients). EEG/fMRI revealed clear hemodynamic changes related to EEG abnormalities in 21 patients. In 18 of these patients, the changes were highly concordant with electro-clinical findings. In the remaining 22 patients, fMRI analysis data failed to show activation or deactivation clusters, probably owing either to lack or inadequate amount of temporal distribution of abnormal EEG activity, or to intrinsic methodological problems. By defining the electro-clinical and hemodynamic correlates of EEG activity, fMRI may shed light on the neurophysiological mechanisms underlying epileptic phenomena. However, as several methodological issues have yet to be addressed, further studies are warranted to assess the reliability and usefulness of EEG/fMRI in clinical practice.

  15. A Retrospective Multicentre Cohort Review of Patient Characteristics and Surgical Aspects versus the Long-Term Outcomes for Recipients of a Fully Implantable Active Middle Ear Implant

    Science.gov (United States)

    Lefebvre, Philippe P.; Gisbert, Javier; Cuda, Domenico; Tringali, Stéphane; Deveze, Arnaud

    2017-01-01

    Objective To summarise treatment outcomes compared to surgical and patient variables for a multicentre recipient cohort using a fully implantable active middle ear implant for hearing impairment. To describe the authors' preferred surgical technique to determine microphone placement. Study Design Multicentre retrospective, observational survey. Setting Five tertiary referral centres. Patients Carina recipients (66 ears, 62 subjects) using the current Cochlear® Carina® System or the legacy device, the Otologics® Fully Implantable Middle Ear, with a T2 transducer. Methods Patient file review and routine clinical review. Patient outcomes assessed were satisfaction, daily use and feedback reports at the first fitting and ≥12 months after implantation. Descriptive and statistical analysis of correlations of variables and their influence on outcomes was performed. Independently reported preferred methods for microphone placement are collectively summarised. Results The average implant experience was 3.5 years. Satisfaction increased significantly over time (p < 0.05). No correlation with covariates examined was observed. Feedback significantly decreased over time, showing a significant correlation with microphone location, primary motivation, gender, age at implantation, and contralateral hearing aid use (p < 0.05). Patient satisfaction was inversely correlated with reports of system feedback (p < 0.05). The implantable microphone was most commonly on the posterior inferior mastoid line, in 42/66 (65%) cases, correlating with less likelihood for feedback and consistent with author surgical preference. Conclusion Carina recipients in this study present as satisfied consistent daily users with very few reports of persistent feedback. As microphone location is an influencing factor, a careful surgical consideration of microphone placement is required. The authors prefer a posterior inferior mastoid line position whenever possible. PMID:28052264

  16. Flow velocity change in the cortical vein during motor activation and its effect on functional brain MRI

    Energy Technology Data Exchange (ETDEWEB)

    Nakajima, Kazuhiro [Kyoto Prefectural Univ. of Medicine (Japan)

    1998-06-01

    On the brain functional magnetic resonance imaging (fMRI) using the gradient-recalled echo technique with clinical MR scanner, the activated areas nearly correspond with the cortical veins. This suggests that the fMRI signal mainly originates from the cortical veins. In this study, we analyzed the flow velocity in the cortical vein quantitatively during brain activation and resting status using 2 dimensional time-of-flight cine MR venography (2D-TOF-cine-MRV) and 2 dimensional phase contrast MRV (2D-PC-MRV) techniques, and demonstrated that the flow velocity increased in the cortical vein corresponding to the activated area during activation status. The increase of flow velocity was calculated to be about 20%. The reason for the increased flow velocity is probably due to the increased regional cerebral blood flow and volume in the activated area. We should be careful to analyze the data of the fMRI because the flow velocity affects the fMRI signal such as the inflow effect and the oblique flow effect. When using the gradient echo method, the effect of the flow velocity is one of the important factors of the fMRI signal. (author)

  17. Ultra-sensitive molecular MRI of cerebrovascular cell activation enables early detection of chronic central nervous system disorders.

    Science.gov (United States)

    Montagne, Axel; Gauberti, Maxime; Macrez, Richard; Jullienne, Amandine; Briens, Aurélien; Raynaud, Jean-Sébastien; Louin, Gaelle; Buisson, Alain; Haelewyn, Benoit; Docagne, Fabian; Defer, Gilles; Vivien, Denis; Maubert, Eric

    2012-11-01

    Since endothelial cells can be targeted by large contrast-carrying particles, molecular imaging of cerebrovascular cell activation is highly promising to evaluate the underlying inflammation of the central nervous system (CNS). In this study, we aimed to demonstrate that molecular magnetic resonance imaging (MRI) of cerebrovascular cell activation can reveal CNS disorders in the absence of visible lesions and symptoms. To this aim, we optimized contrast carrying particles targeting vascular cell adhesion molecule-1 and MRI protocols through both in vitro and in vivo experiments. Although, pre-contrast MRI images failed to reveal the ongoing pathology, contrast-enhanced MRI revealed hypoperfusion-triggered CNS injury in vascular dementia, unmasked amyloid-induced cerebrovascular activation in Alzheimer's disease and allowed monitoring of disease activity during experimental autoimmune encephalomyelitis. Moreover, contrast-enhanced MRI revealed the cerebrovascular cell activation associated with known risk factors of CNS disorders such as peripheral inflammation, ethanol consumption, hyperglycemia and aging. By providing a dramatically higher sensitivity than previously reported methods and molecular contrast agents, the technology described in the present study opens new avenues of investigation in the field of neuroinflammation.

  18. Fusion analysis of functional MRI data for classification of individuals based on patterns of activation.

    Science.gov (United States)

    Ramezani, Mahdi; Abolmaesumi, Purang; Marble, Kris; Trang, Heather; Johnsrude, Ingrid

    2015-06-01

    Classification of individuals based on patterns of brain activity observed in functional MRI contrasts may be helpful for diagnosis of neurological disorders. Prior work for classification based on these patterns have primarily focused on using a single contrast, which does not take advantage of complementary information that may be available in multiple contrasts. Where multiple contrasts are used, the objective has been only to identify the joint, distinct brain activity patterns that differ between groups of subjects; not to use the information to classify individuals. Here, we use joint Independent Component Analysis (jICA) within a Support Vector Machine (SVM) classification method, and take advantage of the relative contribution of activation patterns generated from multiple fMRI contrasts to improve classification accuracy. Young (age: 19-26) and older (age: 57-73) adults (16 each) were scanned while listening to noise alone and to speech degraded with noise, half of which contained meaningful context that could be used to enhance intelligibility. Functional contrasts based on these conditions (and a silent baseline condition) were used within jICA to generate spatially independent joint activation sources and their corresponding modulation profiles. Modulation profiles were used within a non-linear SVM framework to classify individuals as young or older. Results demonstrate that a combination of activation maps across the multiple contrasts yielded an area under ROC curve of 0.86, superior to classification resulting from individual contrasts. Moreover, class separability, measured by a divergence criterion, was substantially higher when using the combination of activation maps.

  19. Neural Changes following Behavioral Activation for a Depressed Breast Cancer Patient: A Functional MRI Case Study

    Directory of Open Access Journals (Sweden)

    Michael J. Gawrysiak

    2012-01-01

    Full Text Available Functional neuroimaging is an innovative but at this stage underutilized method to assess the efficacy of psychotherapy for depression. Functional magnetic resonance imaging (fMRI was used in this case study to examine changes in brain activity in a depressed breast cancer patient receiving an 8-session Behavioral Activation Treatment for Depression (BATD, based on the work of Hopko and Lejuez (2007. A music listening paradigm was used during fMRI brain scans to assess reward responsiveness at pre- and posttreatment. Following treatment, the patient exhibited attenuated depression and changes in blood oxygenation level dependence (BOLD response in regions of the prefrontal cortex and the subgenual cingulate cortex. These preliminary findings outline a novel means to assess psychotherapy efficacy and suggest that BATD elicits functional brain changes in areas implicated in the pathophysiology of depression. Further research is necessary to explore neurobiological mechanisms of change in BATD, particularly the potential mediating effects of reward responsiveness and associated brain functioning.

  20. Time, space and emotion: fMRI reveals content-specific activation during text comprehension.

    Science.gov (United States)

    Ferstl, Evelyn C; von Cramon, D Yves

    2007-11-12

    Story comprehension involves building a situation model of the text, i.e., a representation containing information on the who, where, when and why of the story. Using fMRI at 3T, domain-specific activations for three different information aspects were sought. Twenty participants read two sentence stories half of which contained inconsistencies concerning emotional, temporal or spatial information. Partly replicating previous results [E.C. Ferstl, M. Rinck, D.Y. von Cramon, Emotional and temporal aspects of situation model processing during text comprehension: an event-related fMRI study, J. Cogn. Neurosci. 17 (2005) 724-739], the anterior lateral prefrontal cortex/orbito-frontal cortex proved important for processing temporal information. The left anterior temporal lobe was particularly important during emotional stories. Most importantly, spatial information elicited bilateral activation in the collateral sulci and the posterior cingulate cortex, areas important for visuo-spatial cognition. These findings provide further evidence for content-specific processes during text comprehension.

  1. Cholecalciferol synthesized after UV-activation of 7-dehydrocholesterol onto titanium implants inhibits osteoclastogenesis in vitro.

    Science.gov (United States)

    Satué, María; Ramis, Joana M; Monjo, Marta

    2015-07-01

    UV-activated 7-dehydrocholesterol (7-DHC) has been successfully used as a biocompatible coating for titanium (Ti) implants producing active vitamin D with positive effect on osteoblast differentiation. Since an osseointegrating implant must promote bone formation while delay resorption, here we determine the effect of this coating on the pre-osteoclast cell line RAW 264.7. Moreover, D3 synthesis was optimized by (1) the supplementation with VitE of the 7-DHC coating to reduce 7-DHC oxidation and (2) the addition of an incubation step (48 h at 23°C) after UV-irradiation to favor isomerization. In vitro results with RAW264.7 cells showed no cytotoxic effect of the coatings and a significant decrease of osteoclastogenesis. Indeed, TRAP immunostaining suggested an inhibition of Trap-positive multinucleated cells and the mRNA levels of different phenotypic, fusion, and activity markers were reduced, particularly with 7-DHC:VitE. In conclusion, we demonstrate an improvement of the D3 synthesis from UV-activated 7-DHC when combined with VitE and show that these implants inhibit osteoclastogenesis in vitro.

  2. PWI-MRI and contrast extravasation in brain AVM help to estimate angiogenic activity

    Energy Technology Data Exchange (ETDEWEB)

    Saliou, Guillaume; Toulgoat, Frederique; Ozanne, Augustin; Lasjaunias, Pierre; Ducreux, Denis [Hopital de Bicetre, Service de Neuroradiologie, Kremlin Bicetre cedex (France); Krings, Timo [Hopital de Bicetre, Service de Neuroradiologie, Kremlin Bicetre cedex (France); University of Toronto, Division of Neuroradiology, Department of Medical Imaging, Toronto Western Hospital, UHN, Toronto, ON (Canada); Rutgers, Dik R. [Hopital de Bicetre, Service de Neuroradiologie, Kremlin Bicetre cedex (France); University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands)

    2011-10-15

    The aim of this study is to investigate perfusion characteristics of brain arteriovenous malformation (AVM) by means of MRI perfusion-weighted imaging (PWI). Forty-three patients with brain AVM were prospectively included and investigated by PWI-MRI. Diagnosis of type of disease was made by angiogram. According to angiographic features, the study group was classified in three groups: two groups of patients with classical AVM (group 1 with few or no angiogenic feature (13 patients) and group 2 with many angiogenic features (18 patients)) and one group (group 3) which included patients with cerebral proliferative angiopathy (CPA; 12 patients). Twenty-one patients had never been treated endovascularly for their AVM and 22 patients received partial treatment by endovascular embolisation. Through PWI, corrected cerebral blood volume (CBVc), mean transit time (MTT), and percentage of microvascular leakage (MVL) as an indirect measure of permeability were assessed. The three patient groups did not differ significantly in baseline and clinical parameters. CBVc, MTT, and MVL differed significantly between the three groups (p = 0.003, p = 0.04, p = 0.01, respectively), with the lowest mean values found in group 1 and the highest in group 3. Mean MVL was 11.4 in group 1, 18.6 in group 2, and 21.9 in group 3. MRI can demonstrate differences in PWI parameters among patients with classical AVM and CPA, which are related to angiographic features of these AVMs. Through PWI, the level of angiogenic activity in AVMs may be monitored. (orig.)

  3. fMRI and brain activation after sport concussion: a tale of two cases

    Directory of Open Access Journals (Sweden)

    Michael G Hutchison

    2014-04-01

    Full Text Available Sport-related concussions are now recognized as a major public health concern: The number of participants in sport and recreation is growing, possibly playing their games faster, and there is heightened public awareness of injuries to some high-profile athletes. However, many clinicians still rely on subjective symptom reports for the clinical determination of recovery. Relying on subjective symptom reports can be dangerous, as it has been shown that some concussed athletes may downplay their symptoms. The use of neuropsychological (NP testing tools has enabled clinicians to measure the effects and extent of impairment following concussion more precisely, providing more objective metrics for determining recovery after concussion. Nevertheless, there is a remaining concern that brain abnormalities may exist beyond the point at which individuals achieve recovery in self-reported symptoms and cognition measured by NP testing. Our understanding of brain recovery after concussion is important not only from a neuroscience perspective, but also from the perspective of clinical decision making for safe return-to-play (RTP. A number of advanced neuroimaging tools, including blood oxygen level dependent (BOLD functional magnetic resonance imaging (fMRI, have independently yielded early information on these abnormal brain functions. In the two cases presented in this article, we report contrasting brain activation patterns and recovery profiles using fMRI. Importantly, fMRI was conducted using adapted versions of the most sensitive computerized NP tests administered in current clinical practice to determine impairments and recovery after sport-related concussion. One of the cases is consistent with the concept of lagging brain recovery.

  4. Interictal brain activity differs in migraine with and without aura: resting state fMRI study.

    Science.gov (United States)

    Faragó, Péter; Tuka, Bernadett; Tóth, Eszter; Szabó, Nikoletta; Király, András; Csete, Gergő; Szok, Délia; Tajti, János; Párdutz, Árpád; Vécsei, László; Kincses, Zsigmond Tamás

    2017-12-01

    Migraine is one of the most severe primary headache disorders. The nature of the headache and the associated symptoms during the attack suggest underlying functional alterations in the brain. In this study, we examined amplitude, the resting state fMRI fluctuation in migraineurs with and without aura (MWA, MWoA respectively) and healthy controls. Resting state functional MRI images and T1 high-resolution images were acquired from all participants. For data analysis we compared the groups (MWA-Control, MWA-MWoA, MWoA-Control). The resting state networks were identified by MELODIC. The mean time courses of the networks were identified for each participant for all networks. The time-courses were decomposed into five frequency bands by discrete wavelet decomposition. The amplitude of the frequency-specific activity was compared between groups. Furthermore, the preprocessed resting state images were decomposed by wavelet analysis into five specific frequency bands voxel-wise. The voxel-wise amplitudes were compared between groups by non-parametric permutation test. In the MWA-Control comparison the discrete wavelet decomposition found alterations in the lateral visual network. Higher activity was measured in the MWA group in the highest frequency band (0.16-0.08 Hz). In case of the MWA-MWoA comparison all networks showed higher activity in the 0.08-0.04 Hz frequency range in MWA, and the lateral visual network in in higher frequencies. In MWoA-Control comparison only the default mode network revealed decreased activity in MWoA group in the 0.08-0.04 Hz band. The voxel-wise frequency specific analysis of the amplitudes found higher amplitudes in MWA as compared to MWoA in the in fronto-parietal regions, anterior cingulate cortex and cerebellum. The amplitude of the resting state fMRI activity fluctuation is higher in MWA than in MWoA. These results are in concordance with former studies, which found cortical hyperexcitability in MWA.

  5. Decreased activation of subcortical brain areas in the motor fatigue state: an fMRI study

    Directory of Open Access Journals (Sweden)

    Lijuan Hou

    2016-08-01

    Full Text Available One aspect of motor fatigue is the exercise-induced reduction of neural activity to voluntarily drive the muscle or muscle group. Functional magnetic resonance imaging provides access to investigate the neural activation on the whole brain level and studies observed changes of activation intensity after exercise-induced motor fatigue in the sensorimotor cortex. However, in human, little evidence exists to demonstrate the role of subcortical brain regions in motor fatigue, which is contradict to abundant researches in rodent indicating that during simple movement, the activity of the basal ganglia is modulated by the state of motor fatigue. Thus, in present study, we explored the effect of motor fatigue on subcortical areas in human. A series of fMRI data were collected from 11 healthy subjects while they were executing simple motor tasks in two conditions: before and under the motor fatigue state. The results showed that in both conditions, movements evoked activation volumes in the sensorimotor areas, SMA, cerebellum, thalamus and basal ganglia. Of primary importance are the results that the intensity and size of activation volumes in the subcortical areas (i.e. thalamus and basal ganglia areas are significantly decreased during the motor fatigue state, implying that motor fatigue disturbs the motor control processing in a way that both sensorimotor areas and subcortical brain areas are less active. Further study is needed to clarify how subcortical areas contribute to the overall decreased activity of CNS during motor fatigue state.

  6. Antibiotic-decorated titanium with enhanced antibacterial activity through adhesive polydopamine for dental/bone implant

    Science.gov (United States)

    He, Shu; Zhou, Ping; Wang, Linxin; Xiong, Xiaoling; Zhang, Yifei; Deng, Yi; Wei, Shicheng

    2014-01-01

    Implant-associated infections, which are normally induced by microbial adhesion and subsequent biofilm formation, are a major cause of morbidity and mortality. Therefore, practical approaches to prevent implant-associated infections are in great demand. Inspired by adhesive proteins in mussels, here we have developed a novel antibiotic-decorated titanium (Ti) material with enhanced antibacterial activity. In this study, Ti substrate was coated by one-step pH-induced polymerization of dopamine followed by immobilization of the antibiotic cefotaxime sodium (CS) onto the polydopamine-coated Ti through catechol chemistry. Contact angle measurement and X-ray photoelectron spectroscopy confirmed the presence of CS grafted on the Ti surface. Our results demonstrated that the antibiotic-grafted Ti substrate showed good biocompatibility and well-behaved haemocompatibility. In addition, the antibiotic-grafted Ti could effectively prevent adhesion and proliferation of Escherichia coli (Gram-negative) and Streptococcus mutans (Gram-positive). Moreover, the inhibition of biofilm formation on the antibiotic-decorated Ti indicated that the grafted CS could maintain its long-term antibacterial activity. This modified Ti substrate with enhanced antibacterial activity holds great potential as implant material for applications in dental and bone graft substitutes. PMID:24647910

  7. Activated and deactivated functional brain areas in the Deqi state A functional MRI study

    Institute of Scientific and Technical Information of China (English)

    Yong Huang; Tongjun Zeng; Guifeng Zhang; Ganlong Li; Na Lu; Xinsheng Lai; Yangjia Lu; Jiarong Chen

    2012-01-01

    We compared the activities of functional regions of the brain in the Deqi versus non-Deqi state,as reported by physicians and subjects during acupuncture.Twelve healthy volunteers received sham and true needling at the Waiguan (TE5) acupoint.Real-time cerebral functional MRI showed that compared with non-sensation after sham needling,true needling activated Brodmann areas 3,6,8,9,10,11,13,20,21,37,39,40,43,and 47,the head of the caudate nucleus,the parahippocampal gyrus,thalamus and red nucleus.True needling also deactivated Brodmann areas 1,2,3,4,5,6,7,9,10,18,24,31,40 and 46.

  8. The use of MRI to evaluate posterior thigh muscle activity and damage during nordic hamstring exercise.

    Science.gov (United States)

    Mendiguchia, Jurdan; Arcos, Asier L; Garrues, Mirian A; Myer, Gregory D; Yanci, Javier; Idoate, Fernando

    2013-12-01

    The aim of this study was to investigate the effects of the Nordic hamstring exercise on the biceps femoris long head (BFlh), biceps femoris short head (BFsh), semitendinosus (SMT), and semimembranosus (SMM) muscles. The Nordic hamstring strengthening exercise has been widely used in injury prevention, yet not much is known about the site-specific activation of this exercise on different muscles of the thigh. Eight male national-level referees were assigned to a Nordic hamstring exercise protocol (5 sets of 8 repetitions). Magnetic resonance imaging (MRI) of the subjects' thighs was performed before, within 3 minutes after, and repeated again 72 hours after the exercise intervention. Fifteen axial scans of the thigh interspaced by a distance of 1 of 15 right femur length were obtained from the level of 1 of 15 Lf to 15 of 15 Lf. The MRI data were analyzed for signal intensity changes. After 72 hours, significant changes in transverse (spin-spin) relaxation time signal intensity and cross-sectional area were maintained distally at BFsh cranial portion and concretely at the nondominant limb, whereas no significant changes were observed in transverse (spin-spin) relaxation time signal intensity at BFlh, SMM, or SMT. This study demonstrated that the Nordic hamstring exercise did not result in a uniform response (training stimulus) neither interhamstring (dominant vs. nondominant) nor intrahamstring muscles (same leg) and was better suited for loading proximal BFsh.

  9. In Situ Active Control of Noise in a 4-Tesla MRI Scanner

    Science.gov (United States)

    Li, Mingfeng; Rudd, Brent; Lim, Teik C.; Lee, Jing-Huei

    2011-01-01

    Purpose To evaluate the effectiveness of the proposed active noise control (ANC) system for the reduction of the acoustic noise emission generated by a 4 T MRI scanner during operation and to assess the feasibility of developing an ANC device that can be deployed in situ. Materials and Methods Three typical scanning sequences, namely EPI (echo planar imaging), GEMS (gradient echo multi-slice) and MDEFT (Modified Driven Equilibrium Fourier Transform), were used for evaluating the performance of the ANC system, which was composed of a magnetic compatible headset and a multiple reference feedforward filtered-x least mean square controller. Results The greatest reduction, about 55 dB, was achieved at the harmonic at a frequency of 1.3 kHz in the GEMS case. Approximately 21 dB and 30 dBA overall reduction was achieved for GEMS noise across the entire audible frequency range. For the MDEFT sequence, the control system achieved 14 dB and 14 dBA overall reduction in the audible frequency range, while 13 dB and 14 dBA reduction was obtained for the EPI case. Conclusion The result is highly encouraging because it shows great potential for treating MRI noise with an ANC application during real time scanning. PMID:21751284

  10. Altered default mode network activity in patient with anxiety disorders: An fMRI study

    Energy Technology Data Exchange (ETDEWEB)

    Zhao Xiaohu [Imaging Department of Tong Ji Hospital of Tong Ji University, Shanghai 200065 (China) and Bio-X lab, Department of Physics, Zhe Jiang University, Hangzhou 310027 (China)], E-mail: xhzhao999@263.net; Wang Peijun [Imaging Department of Tong Ji Hospital of Tong Ji University, Shanghai 200065 (China)], E-mail: tongjipjwang@vip.sina.com; Li Chunbo [Department of Psychiatry, Tong Ji Hospital of Tong Ji University, Shanghai 200065 (China)], E-mail: licb@mail.tongji.edu.cn; Hu Zhenghui [Department of Electrical and Engineering, Hong Kong University of Science and Technology, Hong Kong (China)], E-mail: eezhhu@ust.hk; Xi Qian [Imaging Department of Tong Ji Hospital of Tong Ji University, Shanghai 200065 (China)], E-mail: 96125007@sina.com.cn; Wu Wenyuan [Department of Psychiatry, Tong Ji Hospital of Tong Ji University, Shanghai 200065 (China)], E-mail: wuwy@mail.tongji.edu.cn; Tang Xiaowei [Bio-X lab, Department of Physics, Zhe Jiang University, Hangzhou 310027 (China)], E-mail: tangxw@zju.edu.cn

    2007-09-15

    Anxiety disorder, a common mental disorder in our clinical practice, is characterized by unprovoked anxiety. Medial prefrontal cortex (MPFC) and posterior cingulate cortex (PCC), which closely involved in emotional processing, are critical regions in the default mode network. We used functional magnetic resonance imaging (fMRI) to investigate whether default mode network activity is altered in patients with anxiety disorder. Ten anxiety patients and 10 healthy controls underwent fMRI while listening to emotionally neutral words alternating with rest (Experiment 1) and threat-related words alternating with emotionally neutral words (Experiment 2). In Experiment 1, regions of deactivation were observed in patients and controls. In Experiment 2, regions of deactivation were observed only in patients. The observed deactivation patterns in the two experiments, which included MPFC, PCC, and inferior parietal cortex, were similar and consistent with the default model network. Less deactivation in MPFC and greater deactivation in PCC were observed for patients group comparing to controls in Experiment 1. Our observations suggest that the default model network is altered in anxiety patients and dysfunction in MPFC and PCC may play an important role in anxiety psychopathology.

  11. Brain activity underlying auditory perceptual learning during short period training: simultaneous fMRI and EEG recording

    Directory of Open Access Journals (Sweden)

    de Souza Ana Cláudia Silva

    2013-01-01

    Full Text Available Abstract Background There is an accumulating body of evidence indicating that neuronal functional specificity to basic sensory stimulation is mutable and subject to experience. Although fMRI experiments have investigated changes in brain activity after relative to before perceptual learning, brain activity during perceptual learning has not been explored. This work investigated brain activity related to auditory frequency discrimination learning using a variational Bayesian approach for source localization, during simultaneous EEG and fMRI recording. We investigated whether the practice effects are determined solely by activity in stimulus-driven mechanisms or whether high-level attentional mechanisms, which are linked to the perceptual task, control the learning process. Results The results of fMRI analyses revealed significant attention and learning related activity in left and right superior temporal gyrus STG as well as the left inferior frontal gyrus IFG. Current source localization of simultaneously recorded EEG data was estimated using a variational Bayesian method. Analysis of current localized to the left inferior frontal gyrus and the right superior temporal gyrus revealed gamma band activity correlated with behavioral performance. Conclusions Rapid improvement in task performance is accompanied by plastic changes in the sensory cortex as well as superior areas gated by selective attention. Together the fMRI and EEG results suggest that gamma band activity in the right STG and left IFG plays an important role during perceptual learning.

  12. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... metallic items, which can distort MRI images removable dental work pens, pocket knives and eyeglasses body piercings In most cases, an MRI exam is safe for patients with metal implants, except for a few types. People with the ...

  13. Surface thermal oxidation on titanium implants to enhance osteogenic activity and in vivo osseointegration

    Science.gov (United States)

    Wang, Guifang; Li, Jinhua; Lv, Kaige; Zhang, Wenjie; Ding, Xun; Yang, Guangzheng; Liu, Xuanyong; Jiang, Xinquan

    2016-08-01

    Thermal oxidation, which serves as a low-cost, effective and relatively simple/facile method, was used to modify a micro-structured titanium surface in ambient atmosphere at 450 °C for different time periods to improve in vitro and in vivo bioactivity. The surface morphology, crystallinity of the surface layers, chemical composition and chemical states were evaluated by field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Cell behaviours including cell adhesion, attachment, proliferation, and osteogenic differentiation were observed in vitro study. The ability of the titanium surface to promote osseointegration was evaluated in an in vivo animal model. Surface thermal oxidation on titanium implants maintained the microstructure and, thus, both slightly changed the nanoscale structure of titanium and enhanced the crystallinity of the titanium surface layer. Cells cultured on the three oxidized titanium surfaces grew well and exhibited better osteogenic activity than did the control samples. The in vivo bone-implant contact also showed enhanced osseointegration after several hours of oxidization. This heat-treated titanium enhanced the osteogenic differentiation activity of rBMMSCs and improved osseointegration in vivo, suggesting that surface thermal oxidation could potentially be used in clinical applications to improve bone-implant integration.

  14. Disrupted prefrontal activity during emotion processing in complicated grief: An fMRI investigation.

    Science.gov (United States)

    Arizmendi, Brian; Kaszniak, Alfred W; O'Connor, Mary-Frances

    2016-01-01

    Complicated Grief, marked by a persistent and intrusive grief lasting beyond the expected period of adaptation, is associated with a relative inability to disengage from idiographic loss-relevant stimuli (O'Connor and Arizmendi, 2014). In other populations, functional magnetic resonance imaging (fMRI) studies investigating the neural networks associated with this bias consistently implicate the anterior cingulate cortex (ACC) during emotion regulation. In the present study, twenty-eight older adults were categorized into three groups based on grief severity: Complicated Grief (n=8), Non-Complicated Grief (n=9), and Nonbereaved, married controls (n=11). Using a block design, all participants completed 8 blocks (20 stimuli per block) of the ecStroop task during fMRI data acquisition. Differences in neural activity during grief-related (as opposed to neutral) stimuli across groups were examined. Those with Complicated Grief showed an absence of increased rostral ACC (rACC) and fronto-cortical recruitment relative to Nonbereaved controls. Activity in the orbitofrontal cortex (x=6, y=54, z=-10) was significantly elevated in the Non-Complicated Grief group when compared to Nonbereaved controls. Post hoc analysis evidenced activity in the dorsal ACC in the Complicated Grief and Nonbereaved groups late in the task. These findings, supported by behavioral data, suggest a relative inability to recruit the regions necessary for successful completion of this emotional task in those with Complicated Grief. This deficit was not observed in recruitment of the orbitofrontal cortex and the rACC during processing of idiographic semantic stimuli in Non-Complicated Grief.

  15. Non-invasive nano-imaging of ion implanted and activated copper in silicon

    Science.gov (United States)

    Ballout, Fouad; Samson, Jean-Sébastien; Schmidt, Diedrich A.; Bründermann, Erik; Mathis, Yves-Laurent; Gasharova, Biliana; Dirk Wieck, Andreas; Havenith, Martina

    2011-07-01

    Using vibrational imaging techniques including Fourier-transform infrared (FTIR) synchrotron microscopy, Raman microscopy, and scattering scanning near-field infrared microcscopy (s-SNIM), we mapped a sample of phosphor and copper ions implanted in a high-purity silicon wafer. While Raman microscopy monitors the structural disorder within the implantation fields, the aforementionedinfrared techniques provide a detailed picture of the distribution of the free carriers. On a large scale (tens of micrometers), we visualized the channeling effects of phosphor dopants in silicon using FTIR microscopy. In comparison, using s-SNIM we were able to image, on a nanometer scale, local variations of the dielectric properties of the silicon substrate due to the activation of copper dopants.

  16. A least angle regression method for fMRI activation detection in phase-encoded experimental designs.

    Science.gov (United States)

    Li, Xingfeng; Coyle, Damien; Maguire, Liam; McGinnity, Thomas M; Watson, David R; Benali, Habib

    2010-10-01

    This paper presents a new regression method for functional magnetic resonance imaging (fMRI) activation detection. Unlike general linear models (GLM), this method is based on selecting models for activation detection adaptively which overcomes the limitation of requiring a predefined design matrix in GLM. This limitation is because GLM designs assume that the response of the neuron populations will be the same for the same stimuli, which is often not the case. In this work, the fMRI hemodynamic response model is selected from a series of models constructed online by the least angle regression (LARS) method. The slow drift terms in the design matrix for the activation detection are determined adaptively according to the fMRI response in order to achieve the best fit for each fMRI response. The LARS method is then applied along with the Moore-Penrose pseudoinverse (PINV) and fast orthogonal search (FOS) algorithm for implementation of the selected model to include the drift effects in the design matrix. Comparisons with GLM were made using 11 normal subjects to test method superiority. This paper found that GLM with fixed design matrix was inferior compared to the described LARS method for fMRI activation detection in a phased-encoded experimental design. In addition, the proposed method has the advantage of increasing the degrees of freedom in the regression analysis. We conclude that the method described provides a new and novel approach to the detection of fMRI activation which is better than GLM based analyses.

  17. First permanent implant of nerve stimulation leads activated by surface electrodes, enabling hand grasp and release: the stimulus router neuroprosthesis.

    Science.gov (United States)

    Gan, Liu Shi; Ravid, Einat; Kowalczewski, Jan Andrzej; Olson, Jaret Lawrence; Morhart, Michael; Prochazka, Arthur

    2012-05-01

    . More than 150 000 neuroprostheses (NPs) have been implanted in people to restore bodily function in a variety of neural disorders. The authors developed a novel NP, the Stimulus Router System (SRS), in which only passive leads are implanted. Each lead picks up a portion of the current delivered through the skin by an external stimulator. . The authors report on the first human implant of an SRS. . The recipient was a tetraplegic man with bilateral hand paralysis. Three SRS leads were implanted in his right forearm to activate the finger extensors, finger flexors, and thumb flexor. A wristlet containing a surface stimulator and electrodes was used to pass trains of electrical pulses through the skin to each lead. Hand opening and grasp were controlled via a wireless earpiece that sensed small tooth-clicks and transmitted signals to the wristlet. . The current required to activate the muscles was less than half that required prior to implantation and below perceptual threshold. Maximal grip force and hand opening aperture were both larger using the SRS. The implanted leads have remained functional for 3 years. The recipient reported various tasks of daily life that improved during SRS usage. An electronic counter revealed mean monthly usage of 18.5 hours, equivalent to 55 hours of continuous manual activity. . This first implant of the SRS indicates that it can be effective and reliable and has potential to provide an alternative to existing NPs.

  18. Determination of hemisphere dominance for language: comparison of frontal and temporal fMRI activation with intracarotid amytal testing

    Energy Technology Data Exchange (ETDEWEB)

    Spreer, J.; Arnold, S.; Ziyeh, S.; Klisch, J.; Schumacher, M. [Section of Neuroradiology, Neurozentrum, University of Freiburg (Germany); Quiske, A.; Altenmueller, D.; Schulze-Bonhage, A. [Section for Presurgical Epilepsy Diagnosis, Neurozentrum, University of Freiburg (Germany); Wohlfarth, R.; Steinhoff, B.J. [Epilepsiezentrum, Kehl-Kork (Germany); Herpers, M.; Kassubek, J. [Department of Neurology, Neurozentrum, University of Freiburg (Germany); Honegger, J. [Department of Neurosurgery, Neurozentrum, University of Freiburg (Germany)

    2002-06-01

    The reliability of frontal and temporal fMRI activations for the determination of hemisphere language dominance was evaluated in comparison with intracarotid amytal testing (IAT). Twenty-two patients were studied by IAT (bilateral in 13, unilateral in 9 patients) and fMRI using a paradigm requiring semantic decisions. Global and regional (frontal and temporoparietal) lateralisation indices (LI) were calculated from the number of activated (r>0.4) voxels in both hemispheres. Frontolateral activations associated with the language task were seen in all patients, temporoparietal activations in 20 of 22. Regional LI corresponded better with IAT results than global LI. Frontolateral LI were consistent with IAT in all patients with bilateral IAT (including three patients with right dominant and one patient with bilateral language representation) and were not conflicting in any of the patients with unilateral IAT. Temporoparietal LI were discordant with IAT in two patients with atypical language representation. In the determination of hemisphere dominance for language, regional analysis of fMRI activation is superior to global analysis. In cases with clear-cut fMRI lateralisation, i.e. consistent lateralised activation of frontal and temporoparietal language zones, IAT may be unnecessary. FMRI should be performed prior to IAT in all patients going to be operated in brain regions potentially involved in language. (orig.)

  19. Activation of Visuomotor Systems during Visually Guided Movements: A Functional MRI Study

    Science.gov (United States)

    Ellermann, Jutta M.; Siegal, Joel D.; Strupp, John P.; Ebner, Timothy J.; Ugurbil, Kâmil

    1998-04-01

    The dorsal stream is a dominant visuomotor pathway that connects the striate and extrastriate cortices to posterior parietal areas. In turn, the posterior parietal areas send projections to the frontal primary motor and premotor areas. This cortical pathway is hypothesized to be involved in the transformation of a visual input into the appropriate motor output. In this study we used functional magnetic resonance imaging (fMRI) of the entire brain to determine the patterns of activation that occurred while subjects performed a visually guided motor task. In nine human subjects, fMRI data were acquired on a 4-T whole-body MR system equipped with a head gradient coil and a birdcage RF coil using aT*2-weighted EPI sequence. Functional activation was determined for three different tasks: (1) a visuomotor task consisting of moving a cursor on a screen with a joystick in relation to various targets, (2) a hand movement task consisting of moving the joystick without visual input, and (3) a eye movement task consisting of moving the eyes alone without visual input. Blood oxygenation level-dependent (BOLD) contrast-based activation maps of each subject were generated using period cross-correlation statistics. Subsequently, each subject's brain was normalized to Talairach coordinates, and the individual maps were compared on a pixel by pixel basis. Significantly activated pixels common to at least four out of six subjects were retained to construct the final functional image. The pattern of activation during visually guided movements was consistent with the flow of information from striate and extrastriate visual areas, to the posterior parietal complex, and then to frontal motor areas. The extensive activation of this network and the reproducibility among subjects is consistent with a role for the dorsal stream in transforming visual information into motor behavior. Also extensively activated were the medial and lateral cerebellar structures, implicating the cortico

  20. Biocompatibility and anti-microbiological activity characterization of novel coatings for dental implants: A primer for non-biologists

    Directory of Open Access Journals (Sweden)

    Thomas K Monsees

    2016-08-01

    Full Text Available With regard to biocompatibility, the cardinal requirement for dental implants and other medical devices that are in long-term contact with tissue is that the material does not cause any adverse effect to the patient. To warrant stability and function of the implant, proper osseointegration is a further prerequisite. Cells interact with the implant surface as the interface between bulk material and biological tissue. Whereas structuring, deposition of a thin film or other modifications of the surface are crucial parameters in determining favorable adhesion of cells, corrosion of metal surfaces and release of ions can affect cell viability. Both parameters are usually tested using in vitro cytotoxicity and adhesion assays with bone or fibroblasts cells. For bioactive surface modifications, further tests should be considered for biocompatibility evaluation. Depending on the type of modification, this may include analysis of specific cell functions or the determination of antimicrobial activities. The latter is of special importance as bacteria and yeast present in the oral cavity can be introduced during the implantation process and this may lead to chronic infections and implant failure. An antimicrobial coating of the implant is a way to avoid that. This review describes the essential biocompatibility assays for evaluation of new implant materials required by ISO 10993 and also gives an overview on recent test methods for specific coatings of dental implants.

  1. Biocompatibility and anti-microbiological activity characterization of novel coatings for dental implants: A primer for non-biologists

    Science.gov (United States)

    Monsees, Thomas

    2016-08-01

    With regard to biocompatibility, the cardinal requirement for dental implants and other medical devices that are in long-term contact with tissue is that the material does not cause any adverse effect to the patient. To warrant stability and function of the implant, proper osseointegration is a further prerequisite. Cells interact with the implant surface as the interface between bulk material and biological tissue. Whereas structuring, deposition of a thin film or other modifications of the surface are crucial parameters in determining favorable adhesion of cells, corrosion of metal surfaces and release of ions can affect cell viability. Both parameters are usually tested using in vitro cytotoxicity and adhesion assays with bone or fibroblasts cells. For bioactive surface modifications, further tests should be considered for biocompatibility evaluation. Depending on the type of modification, this may include analysis of specific cell functions or the determination of antimicrobial activities. The latter is of special importance as bacteria and yeast present in the oral cavity can be introduced during the implantation process and this may lead to chronic infections and implant failure. An antimicrobial coating of the implant is a way to avoid that. This review describes the essential biocompatibility assays for evaluation of new implant materials required by ISO 10993 and also gives an overview on recent test methods for specific coatings of dental implants.

  2. Assessing the spatiotemporal evolution of neuronal activation with single-trial event-related potentials and functional MRI.

    Science.gov (United States)

    Eichele, Tom; Specht, Karsten; Moosmann, Matthias; Jongsma, Marijtje L A; Quiroga, Rodrigo Quian; Nordby, Helge; Hugdahl, Kenneth

    2005-12-06

    The brain acts as an integrated information processing system, which methods in cognitive neuroscience have so far depicted in a fragmented fashion. Here, we propose a simple and robust way to integrate functional MRI (fMRI) with single trial event-related potentials (ERP) to provide a more complete spatiotemporal characterization of evoked responses in the human brain. The idea behind the approach is to find brain regions whose fMRI responses can be predicted by paradigm-induced amplitude modulations of simultaneously acquired single trial ERPs. The method was used to study a variant of a two-stimulus auditory target detection (odd-ball) paradigm that manipulated predictability through alternations of stimulus sequences with random or regular target-to-target intervals. In addition to electrophysiologic and hemodynamic evoked responses to auditory targets per se, single-trial modulations were expressed during the latencies of the P2 (170-ms), N2 (200-ms), and P3 (320-ms) components and predicted spatially separated fMRI activation patterns. These spatiotemporal matches, i.e., the prediction of hemodynamic activation by time-variant information from single trial ERPs, permit inferences about regional responses using fMRI with the temporal resolution provided by electrophysiology.

  3. Nouns, verbs, objects, actions, and abstractions: local fMRI activity indexes semantics, not lexical categories.

    Science.gov (United States)

    Moseley, Rachel L; Pulvermüller, Friedemann

    2014-05-01

    Noun/verb dissociations in the literature defy interpretation due to the confound between lexical category and semantic meaning; nouns and verbs typically describe concrete objects and actions. Abstract words, pertaining to neither, are a critical test case: dissociations along lexical-grammatical lines would support models purporting lexical category as the principle governing brain organisation, whilst semantic models predict dissociation between concrete words but not abstract items. During fMRI scanning, participants read orthogonalised word categories of nouns and verbs, with or without concrete, sensorimotor meaning. Analysis of inferior frontal/insula, precentral and central areas revealed an interaction between lexical class and semantic factors with clear category differences between concrete nouns and verbs but not abstract ones. Though the brain stores the combinatorial and lexical-grammatical properties of words, our data show that topographical differences in brain activation, especially in the motor system and inferior frontal cortex, are driven by semantics and not by lexical class.

  4. Auditory cerebral activation patterns of Chinese English learners by fMRI

    Institute of Scientific and Technical Information of China (English)

    SHEN Tong; HU Zi-cheng; LI Yong; ZHANG Yong; XIE Peng; LV Fa-jin; LUO Tian-you; MU Jun

    2008-01-01

    Objective:To identify the cerebral activation patterns associated with the processes that occur during viewing Chinese and English words in native Chinese English learners.Methods:12 right-handed Chinese English hamers were divided into two groups equally,namely English majors and non-English majors,and took semantic judgement tasks of both English and Chinese words,for whom the fMRI images were coUected.Results:To various degrees,all subjects demonstrated activation of associated cerebral regions in both hemispheres and the left hemisphere activation was more significant for most subjects.Except for elassieal regions involved in language processing,such as Wemicke areas and Broca areas,there were other activated cerebral regions,including cerebellum,limbic system and basal ganglia nucleus,etc.To sum up,there were apparent overlap for cerebral activation distribution and no specific processing areas for both tasks.The analysis of ROI(region of interest)suggested that subjects in specialized group were more dependent on right hemisphere to perform English words task.Conclus/on:Language cognition is dominated by left hemisphere,which is also shared by the right hemisphere to various degrees and thus two hemispheres work by ways of both dissociation and coordination.It is possible that working strategy of the right hemisphere in English task is related to proficiency of the second language.A variety of distinctions are shared by each subject for language cognitive patterns.

  5. Optimization of Visual Tasks for Detecting Visual Cortex Activity in fMRI Studies

    Directory of Open Access Journals (Sweden)

    "A. Mirzajani

    2005-08-01

    Full Text Available Introduction: functional magnetic resonance imaging is a useful non-invasive technique for the evaluation and mapping of human brain, especially the visual cortex. One of the most important subjects in this background is optimizing visual stimuli in various forms of visual tasks for acquiring significant and ro-bust signals. Materials and methods: The effects of physical pa-rameters of visual stimuli on 14 healthy volunteers for detecting visual cortical activity were evaluated by functional magnetic resonance imaging. These pa-rameters were temporal frequency (TF, different pat-terns of activation including, square wave and sine wave grating, and two different states of rest includ-ing black and white screens. Results: The results showed that BOLD signal will be maximally in the TF of 8 Hz, and use the black screen in the rest state. However there was not significant difference between square-¬wave and sine-wave grat-ings in producing visual activation in the cortex. Conclusion: Physical parameters of visual tasks are effective in detecting visual cortical activity, and it is necessary to pay attention to them in order to get sig-nificant and robust signal. Visual tasks with TF of 8 Hz and one pattern of square-wave or sine-wave in activation state, and black screen in rest state are op-timally suitable for fMRI studies.

  6. Inefficient preparatory fMRI-BOLD network activations predict working memory dysfunctions in patients with schizophrenia

    Directory of Open Access Journals (Sweden)

    Anja eBaenninger

    2016-03-01

    Full Text Available Patients with schizophrenia show abnormal dynamics and structure of temporally coherent networks (TCNs assessed using fMRI, which undergo adaptive shifts in preparation for a cognitively demanding task. During working memory (WM tasks, patients with schizophrenia show persistent deficits in TCNs as well as EEG indices of WM. Studying their temporal relationship during WM tasks might provide novel insights into WM performance deficits seen in schizophrenia.Simultaneous EEG-fMRI data were acquired during the performance of a verbal Sternberg WM task with two load levels (load 2 & load 5 in 17 patients with schizophrenia and 17 matched healthy controls. Using covariance mapping, we investigated the relationship of the activity in the TCNs before the memoranda were encoded and EEG spectral power during the retention interval. We assessed four TCNs – default mode network (DMN, dorsal attention network (dAN, left and right working memory networks (WMNs – and three EEG bands – theta, alpha, and beta.In healthy controls, there was a load dependent inverse relation between DMN and frontal-midline theta power and an anti-correlation between DMN and dAN. Both effects were not significantly detectable in patients. In addition, healthy controls showed a left-lateralized load-dependent recruitment of the WMNs. Activation of the WMNs was bilateral in patients, suggesting more resources were recruited for successful performance on the WM task.Our findings support the notion of schizophrenia patients showing deviations in their neurophysiological responses before the retention of relevant information in a verbal WM task. Thus, treatment strategies as neurofeedback targeting pre-states could be beneficial as task performance relies on the preparatory state of the brain.

  7. Value of MRI in diagnosing sensorineural hearing loss in children before cochlear implantation%MRI对儿童感音神经性耳聋人工耳蜗植入术前的诊断价值

    Institute of Scientific and Technical Information of China (English)

    赵凯; 张岚

    2015-01-01

    Objective To investigate the value of MRI in children with sensorineural hearing loss (SNHL) before cochlear implantation. Methods MRI of 80 children with SHNL was retrospectively analyzed in correlation with the classification of inner ear malformation. Results Of 80 children with 160 ears,.152 inner ear malformations involved the cochlea (38),.vestibula (33), semicircular canal (41), internal auditory canal (40), vestibular aqueduct (37), and cochlear nerve (46). Conclusion MRI provides detailed and reliable anatomical information for classification of SNHL in children before cochlear implantation.%目的:探讨磁共振成像在儿童感音神经性耳聋(SNHL)人工耳蜗植入术前的诊断价值及临床应用。方法回顾性分析80例临床诊断为SNHL拟行人工耳蜗植入的患儿MRI图像,结合内耳畸形的最新分类标准进行影像学分类诊断。结果80例(160耳)发现中内耳畸形152耳,其中耳蜗畸形38耳,前庭畸形33耳,半规管畸形41耳,内耳道畸形40耳,前庭导水管扩大37耳,蜗神经畸形46耳。结论 MRI能对儿童感音神经性耳聋人工耳蜗植入术前提供丰富详细的解剖学信息,并进行分类诊断,对指导手术、评估预后等都具有重要的临床意义。

  8. MRI of the transverse and alar ligaments in rheumatoid arthritis: feasibility and relations to atlantoaxial subluxation and disease activity

    Energy Technology Data Exchange (ETDEWEB)

    Vetti, Nils; Kraakenes, Jostein; Roervik, Jarle; Espeland, Ansgar [Haukeland University Hospital, Department of Radiology, Bergen (Norway); University of Bergen, Section for Radiology, Department of Surgical Sciences, Bergen (Norway); Alsing, Rikke; Brun, Johan Gorgas [Haukeland University Hospital, Department of Rheumatology, Bergen (Norway); University of Bergen, Section for Rheumatology, Institute of Medicine, Bergen (Norway); Gilhus, Nils Erik [Haukeland University Hospital, Department of Neurology, Bergen (Norway); University of Bergen, Section for Neurology, Department of Clinical Medicine, Bergen (Norway)

    2010-03-15

    Dysfunctional transverse and alar craniovertebral ligaments can cause instability and osseous destruction in rheumatoid arthritis (RA). This study examined (1) the feasibility of high-resolution magnetic resonance imaging (MRI) of these ligaments in RA and (2) the relation between ligament high-signal changes and atlantoaxial subluxation and RA duration/severity. Consecutive RA patients (n=46) underwent clinical examination, functional radiography, and high-resolution MRI. Two blinded radiologists rated MRI image quality, graded ligament high-signal changes 0-3 on proton-weighted sequences using an existing grading system, and assessed cervical spine rheumatic changes on short tau inversion recovery images. Agreement was analyzed using kappa and relations using multiple logistic regression. MRI images had good quality in 42 (91.3%) of 46 patients and were interpretable in 44 (32 women and 12 men, median age/disease duration 60.4/9.1 years). MRI grades 2-3 changes of the transverse and alar ligaments showed moderate and good interobserver agreement (kappa 0.59 and 0.78), respectively, and prevalence 31.8% and 34.1%. Such ligament changes were more frequent with increasing anterior atlantoaxial subluxation (p=0.012 transverse, p=0.028 alar), higher erythrocyte sedimentation rate (p=0.003 transverse), positive rheumatoid factor (p=0.002 alar), and neck pain (p = 0.004 alar). This first study of high-resolution MRI of these ligaments in RA showed high feasibility and relations with atlantoaxial subluxation, RA disease activity, and neck pain. The clinical usefulness of such MRI needs further evaluation. (orig.)

  9. Cobalt Alloy Implant Debris Induces Inflammation and Bone Loss Primarily through Danger Signaling, Not TLR4 Activation: Implications for DAMP-ening Implant Related Inflammation.

    Science.gov (United States)

    Samelko, Lauryn; Landgraeber, Stefan; McAllister, Kyron; Jacobs, Joshua; Hallab, Nadim James

    2016-01-01

    Cobalt alloy debris has been implicated as causative in the early failure of some designs of current total joint implants. The ability of implant debris to cause excessive inflammation via danger signaling (NLRP3 inflammasome) vs. pathogen associated pattern recognition receptors (e.g. Toll-like receptors; TLRs) remains controversial. Recently, specific non-conserved histidines on human TLR4 have been shown activated by cobalt and nickel ions in solution. However, whether this TLR activation is directly or indirectly an effect of metals or secondary endogenous alarmins (danger-associated molecular patterns, DAMPs) elicited by danger signaling, remains unknown and contentious. Our study indicates that in both a human macrophage cell line (THP-1) and primary human macrophages, as well as an in vivo murine model of inflammatory osteolysis, that Cobalt-alloy particle induced NLRP3 inflammasome danger signaling inflammatory responses were highly dominant relative to TLR4 activation, as measured respectively by IL-1β or TNF-α, IL-6, IL-10, tissue histology and quantitative bone loss measurement. Despite the lack of metal binding histidines H456 and H458 in murine TLR4, murine calvaria challenge with Cobalt alloy particles induced significant macrophage driven in vivo inflammation and bone loss inflammatory osteolysis, whereas LPS calvaria challenge alone did not. Additionally, no significant increase (pCobalt vs. Cobalt alone was evident, even at high levels of LPS (i.e. levels commiserate with hematogenous levels in fatal sepsis, >500pg/mL). Therefore, not only do the results of this investigation support Cobalt alloy danger signaling induced inflammation, but under normal homeostasis low levels of hematogenous PAMPs (Cobalt alloy metal implant debris. This suggests the unique nature of Cobalt alloy particle bioreactivity is strong enough to illicit danger signaling that secondarily activate concomitant TLR activation, and may in part explain Cobalt particulate

  10. Brain activation profiles during kinesthetic and visual imagery: An fMRI study.

    Science.gov (United States)

    Kilintari, Marina; Narayana, Shalini; Babajani-Feremi, Abbas; Rezaie, Roozbeh; Papanicolaou, Andrew C

    2016-09-01

    The aim of this study was to identify brain regions involved in motor imagery and differentiate two alternative strategies in its implementation: imagining a motor act using kinesthetic or visual imagery. Fourteen adults were precisely instructed and trained on how to imagine themselves or others perform a movement sequence, with the aim of promoting kinesthetic and visual imagery, respectively, in the context of an fMRI experiment using block design. We found that neither modality of motor imagery elicits activation of the primary motor cortex and that each of the two modalities involves activation of the premotor area which is also activated during action execution and action observation conditions, as well as of the supplementary motor area. Interestingly, the visual and the posterior cingulate cortices show reduced BOLD signal during both imagery conditions. Our results indicate that the networks of regions activated in kinesthetic and visual imagery of motor sequences show a substantial, while not complete overlap, and that the two forms of motor imagery lead to a differential suppression of visual areas. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Synovitis and osteitis are very frequent in rheumatoid arthritis clinical remission: results from an MRI study of 294 patients in clinical remission or low disease activity state

    DEFF Research Database (Denmark)

    Gandjbakhch, Frédérique; Conaghan, Philip G; Ejbjerg, Bo;

    2011-01-01

    In rheumatoid arthritis (RA), radiographic progression may occur despite clinical remission. This may be explained by subclinical inflammation. Magnetic resonance imaging (MRI) provides a greater sensitivity than clinical examination and radiography for assessing disease activity. Our objective w...... was to determine the MRI characteristics of RA patients in clinical remission or low disease activity (LDA) state....

  12. Brain activity underlying auditory perceptual learning during short period training: simultaneous fMRI and EEG recording

    OpenAIRE

    2013-01-01

    Abstract Background There is an accumulating body of evidence indicating that neuronal functional specificity to basic sensory stimulation is mutable and subject to experience. Although fMRI experiments have investigated changes in brain activity after relative to before perceptual learning, brain activity during perceptual learning has not been explored. This work investigated brain activity related to auditory frequency discrimination learning using a variational Bayesian approach for sourc...

  13. Performance evaluation of nonnegative matrix factorization algorithms to estimate task-related neuronal activities from fMRI data.

    Science.gov (United States)

    Ding, Xiaoyu; Lee, Jong-Hwan; Lee, Seong-Whan

    2013-04-01

    Nonnegative matrix factorization (NMF) is a blind source separation (BSS) algorithm which is based on the distinct constraint of nonnegativity of the estimated parameters as well as on the measured data. In this study, according to the potential feasibility of NMF for fMRI data, the four most popular NMF algorithms, corresponding to the following two types of (1) least-squares based update [i.e., alternating least-squares NMF (ALSNMF) and projected gradient descent NMF] and (2) multiplicative update (i.e., NMF based on Euclidean distance and NMF based on divergence cost function), were investigated by using them to estimate task-related neuronal activities. These algorithms were applied firstly to individual data from a single subject and, subsequently, to group data sets from multiple subjects. On the single-subject level, although all four algorithms detected task-related activation from simulated data, the performance of multiplicative update NMFs was significantly deteriorated when evaluated using visuomotor task fMRI data, for which they failed in estimating any task-related neuronal activities. In group-level analysis on both simulated data and real fMRI data, ALSNMF outperformed the other three algorithms. The presented findings may suggest that ALSNMF appears to be the most promising option among the tested NMF algorithms to extract task-related neuronal activities from fMRI data.

  14. Likelihood-Based Hypothesis Tests for Brain Activation Detection From MRI Data Disturbed by Colored Noise: A Simulation Study

    NARCIS (Netherlands)

    Den Dekker, A.J.; Poot, D.H.J.; Bos, R.; Sijbers, J.

    2009-01-01

    Functional magnetic resonance imaging (fMRI) data that are corrupted by temporally colored noise are generally preprocessed (i.e., prewhitened or precolored) prior to functional activation detection. In this paper, we propose likelihood-based hypothesis tests that account for colored noise directly

  15. Electrical activation of nitrogen heavily implanted 3C-SiC(1 0 0)

    Energy Technology Data Exchange (ETDEWEB)

    Li, Fan, E-mail: f.li.1@warwick.ac.uk [School of Engineering, University of Warwick, Coventry CV4 7AL (United Kingdom); Sharma, Yogesh; Shah, Vishal; Jennings, Mike [School of Engineering, University of Warwick, Coventry CV4 7AL (United Kingdom); Pérez-Tomás, Amador [ICN2 – Institut Catala de Nanociència i Nanotecnologia, Campus UAB, 08193 Bellaterra, Barcelona (Spain); Myronov, Maksym [Physics Department, University of Warwick, Coventry CV4 7AL (United Kingdom); Fisher, Craig [School of Engineering, University of Warwick, Coventry CV4 7AL (United Kingdom); Leadley, David [Physics Department, University of Warwick, Coventry CV4 7AL (United Kingdom); Mawby, Phil [School of Engineering, University of Warwick, Coventry CV4 7AL (United Kingdom)

    2015-10-30

    Highlights: • Nitrogen is fully activated by 1175 °C annealing for 1.5 × 10{sup 19} cm{sup −3} doped 3C-SiC. • Free donor concentration is found to readily saturate in 3C-SiC at ∼7 × 10{sup 19} cm{sup −3}. • 3C-SiC is found to have complete donor thermal ionization above 150 K. • Donor in 1.5 × 10{sup 19} cm{sup −3} nitrogen implanted 3C-SiC has an energy level ∼15 meV. • The SiO{sub 2} cap is found to have a bigger influence on low and medium doped samples. - Abstract: A degenerated wide bandgap semiconductor is a rare system. In general, implant levels lie deeper in the band-gap and carrier freeze-out usually takes place at room temperature. Nevertheless, we have observed that heavily doped n-type degenerated 3C-SiC films are achieved by nitrogen implantation level of ∼6 × 10{sup 20} cm{sup −3} at 20 K. According to temperature dependent Hall measurements, nitrogen activation rates decrease with the doping level from almost 100% (1.5 × 10{sup 19} cm{sup −3}, donor level 15 meV) to ∼12% for 6 × 10{sup 20} cm{sup −3}. Free donors are found to saturate in 3C-SiC at ∼7 × 10{sup 19} cm{sup −3}. The implanted film electrical performances are characterized as a function of the dopant doses and post implantation annealing (PIA) conditions by fabricating Van der Pauw structures. A deposited SiO{sub 2} layer was used as the surface capping layer during the PIA process to study its effect on the resultant film properties. From the device design point of view, the lowest sheet resistivity (∼1.4 mΩ cm) has been observed for medium doped (4 × 10{sup 19} cm{sup −3}) sample with PIA 1375 °C 2 h without a SiO{sub 2} cap.

  16. Lateralization of functional magnetic resonance imaging (fMRI) activation in the auditory pathway of patients with lateralized tinnitus

    Energy Technology Data Exchange (ETDEWEB)

    Smits, Marion [Erasmus MC - University Medical Center Rotterdam, Department of Radiology, Hs 224, Rotterdam (Netherlands); Kovacs, Silvia; Peeters, Ronald R.; Hecke, Paul van; Sunaert, Stefan [University Hospitals of the Catholic University Leuven, Department of Radiology, Leuven (Belgium); Ridder, Dirk de [University of Antwerp, Department of Neurosurgery, Edegem (Belgium)

    2007-08-15

    Tinnitus is hypothesized to be an auditory phantom phenomenon resulting from spontaneous neuronal activity somewhere along the auditory pathway. We performed fMRI of the entire auditory pathway, including the inferior colliculus (IC), the medial geniculate body (MGB) and the auditory cortex (AC), in 42 patients with tinnitus and 10 healthy volunteers to assess lateralization of fMRI activation. Subjects were scanned on a 3T MRI scanner. A T2*-weighted EPI silent gap sequence was used during the stimulation paradigm, which consisted of a blocked design of 12 epochs in which music presented binaurally through headphones, which was switched on and off for periods of 50 s. Using SPM2 software, single subject and group statistical parametric maps were calculated. Lateralization of activation was assessed qualitatively and quantitatively. Tinnitus was lateralized in 35 patients (83%, 13 right-sided and 22 left-sided). Significant signal change (P{sub corrected} < 0.05) was found bilaterally in the primary and secondary AC, the IC and the MGB. Signal change was symmetrical in patients with bilateral tinnitus. In patients with lateralized tinnitus, fMRI activation was lateralized towards the side of perceived tinnitus in the primary AC and IC in patients with right-sided tinnitus, and in the MGB in patients with left-sided tinnitus. In healthy volunteers, activation in the primary AC was left-lateralized. Our paradigm adequately visualized the auditory pathways in tinnitus patients. In lateralized tinnitus fMRI activation was also lateralized, supporting the hypothesis that tinnitus is an auditory phantom phenomenon. (orig.)

  17. Single subject pharmacological-MRI (phMRI study: Modulation of brain activity of psoriatic arthritis pain by cyclooxygenase-2 inhibitor

    Directory of Open Access Journals (Sweden)

    Chialvo DR

    2005-11-01

    Full Text Available Abstract We use fMRI to examine brain activity for pain elicited by palpating joints in a single patient suffering from psoriatic arthritis. Changes in these responses are documented when the patient ingested a single dose of a selective cyclooxygenase-2 inhibitor (COX-2i. We show that mechanical stimulation of the painful joints exhibited a cortical activity pattern similar to that reported for acute pain, with activity primarily localized to the thalamus, insular, primary and secondary somatosensory cortices and the mid anterior cingulum. COX-2i resulted in significant decreased in reported pain intensity and in brain activity after 1 hour of administration. The anterior insula and SII correlated with pain intensity, however no central activation site for the drug was detected. We demonstrate the similarity of the activation pattern for palpating painful joints to brain activity in normal subjects in response to thermal painful stimuli, by performing a spatial conjunction analysis between these maps, where overlap is observed in the insula, thalamus, secondary somatosensory cortex, and anterior cingulate. The results demonstrate that one can study effects of pharmacological manipulations in a single subject where the brain activity for a clinical condition is delineated and its modulation by COX-2i demonstrated. This approach may have diagnostic and prognostic utility.

  18. ANTI IMPLANTATION AND PREGNANCY INTERRUPTION ACTIVITY OF JAPAKUSUMA (HIBISCUS ROSA SINENSIS IN ALBINO RATS

    Directory of Open Access Journals (Sweden)

    Kashinath Hadimur

    2013-06-01

    Full Text Available Increase in population has affected many socio-economic conditions of people by increasing crimes, illiteracy, destructive activities, diseases, improper food and shelter. Thus to control this population and limit the family size at a personal level and at a national level, modern contraceptive methods and medicines were introduced long back. There are many new contraceptives available now, but they have various side effects. Some traditional practitioners used to dispense oral contraceptives mentioned in Ayurvedic classics. Such as 1 Pippali (Piper longum, Vidanga (Emblica ribes and Tankana (Sodii Biboras. 2 Talisapatra (Taxus baccata and Gairika (Hematite with cold water and 3 Kanji bhavita Japakusuma (Hibiscus rosa sinensis. An experimental study on above mentioned 1 and 2 formulations has proved its efficacy as temporary contraceptive medicine. To evaluate the permanent or long term temporary contraceptive effect of Japakusuma, an attempt was made in this study. Study was conducted by Choudary and Khanna method on 18 female, 36 male (for mating albino rats. Japakusuma, Propylene glycol, Ovral L formed the materials. Single dose was administered on proestrous stage of rat oestrous cycle and observed for anti-implantation and pregnancy interruption activity. Test drug showed significant anti implantation and pregnancy interruption activity. Thus showing the temporary contraceptive activity of Japakusuma (Hibiscus rosa sinensis.

  19. Changes in singing performance and fMRI activation following right temporal lobe surgery.

    Science.gov (United States)

    Wilson, Sarah J; Abbott, David F; Tailby, Chris; Gentle, Ellen C; Merrett, Dawn L; Jackson, Graeme D

    2013-10-01

    This study arose in the context of having to estimate risk to the musical abilities of a trained singer (patient A.M.) recommended for right anterior temporal lobectomy (RATL) to ameliorate medically intractable seizures. To date there has been no systematic investigation of reorganisation of musical functions in the presence of epileptogenic lesions, although it is well established that RATL can impair pitch processing in nonmusicians. Using fMRI, we compared the network activated by covert singing with lyrics in A.M. before and after surgery, while taking language activation and singing expertise into consideration. Before surgery, A.M. showed lower pitch accuracy of singing relative to individuals of similar experience (experts), thus we compared her to 12 healthy controls matched for singing pitch accuracy. We found atypical organisation of A.M.'s singing network before surgery in the presence of a malformation of cortical development, including partial activation of the singing network of pitch-matched controls, and diffuse activation along the midline spreading laterally into association cortex, typical of generalised cortical hyperexcitability in intractable epilepsy. After tailored RATL, A.M. showed striking behavioural and neuroimaging changes, including significant improvement in pitch accuracy of singing relative to controls (p = .026) and the subjective experience of being a more technically proficient singer. This was accompanied by a significant reduction in cortical activation (p singing activation emerging, including decreased involvement of frontal language regions. These changes were largely specific to singing, with A.M. showing language activation and performance similar to controls. This case provides evidence for selective disruption of the singing network that reorganised after successful resection of an epileptogenic lesion and likely occurred through decoupling of the singing and language networks. Crown Copyright © 2013. Published by

  20. TiO2 nanotubes: N-ion implantation at low-dose provides noble-metal-free photocatalytic H2-evolution activity

    CERN Document Server

    Zhou, Xuemei; Liu, Ning; Nguyen, Nhat Truong; Zolnhofer, Eva M; Tsuchiya, Hiroaki; Killian, Manuela S; Meyer, Karsten; Frey, Lothar; Schmuki, Patrik

    2016-01-01

    Low-dose nitrogen implantation induces in TiO2 nanotubes a co-catalytic activity for photocatalytic H2-evolution. The use of an ion implantation process leads to a N-implanted zone only at the top part of the tubes. The coupling of this top layer and the underlying non-implanted part of the nanotubes strongly contributes to an efficient carrier separation and thus to a significantly enhanced H2 generation.

  1. MB-SWIFT functional MRI during deep brain stimulation in rats.

    Science.gov (United States)

    Lehto, Lauri J; Idiyatullin, Djaudat; Zhang, Jinjin; Utecht, Lynn; Adriany, Gregor; Garwood, Michael; Gröhn, Olli; Michaeli, Shalom; Mangia, Silvia

    2017-08-07

    Recently introduced 3D radial MRI pulse sequence entitled Multi-Band SWeep Imaging with Fourier Transformation (MB-SWIFT) having virtually zero acquisition delay was used to obtain functional MRI (fMRI) contrast in rat's brain at 9.4 T during deep brain stimulation (DBS). The results demonstrate that MB-SWIFT allows functional images free of susceptibility artifacts, and provides an excellent fMRI activation contrast in the brain. Flip angle dependence of the MB-SWIFT fMRI signal and elimination of the fMRI contrast while using saturation bands, indicate a blood flow origin of the observed fMRI contrast. MB-SWIFT fMRI modality permits activation studies in the close proximity to an implanted lead, which is not possible to achieve with conventionally used gradient echo and spin echo - echo planar imaging fMRI techniques. We conclude that MB-SWIFT fMRI is a powerful imaging modality for investigations of functional responses during DBS. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  2. Brain activity during driving with distraction: an immersive fMRI study

    Directory of Open Access Journals (Sweden)

    Tom A Schweizer

    2013-02-01

    Full Text Available Introduction: Non-invasive measurements of brain activity have an important role to play in understanding driving ability. The current study aimed to identify the neural underpinnings of human driving behavior by visualizing the areas of the brain involved in driving under different levels of demand, such as driving while distracted or making left turns at busy intersections. Methods: To capture brain activity during driving, we placed a driving simulator with a fully functional steering wheel and pedals in a 3.0 Tesla functional magnetic resonance imaging (fMRI system. To identify the brain areas involved while performing different real-world driving maneuvers, participants completed tasks ranging from simple (right turns to more complex (left turns at busy intersections. To assess the effects of driving while distracted, participants were asked to perform an auditory task while driving analogous to speaking on a hands-free device and driving. Results: A widely distributed brain network was identified, especially when making left turns at busy intersections compared to more simple driving tasks. During distracted driving, brain activation shifted dramatically from the posterior, visual and spatial areas to the prefrontal cortex. Conclusions: Our findings suggest that the distracted brain sacrificed areas in the posterior brain important for visual attention and alertness to recruit enough brain resources to perform a secondary, cognitive task. The present findings offer important new insights into the scientific understanding of the neuro-cognitive mechanisms of driving behavior and lay down an important foundation for future clinical research.

  3. Mirror neuron activation in children with developmental coordination disorder: A functional MRI study.

    Science.gov (United States)

    Reynolds, Jess E; Licari, Melissa K; Billington, Jac; Chen, Yihui; Aziz-Zadeh, Lisa; Werner, Julie; Winsor, Anne M; Bynevelt, Michael

    2015-12-01

    The aim of this study was to reveal cortical areas that may contribute to the movement difficulties seen in children with Developmental Coordination Disorder (DCD). Specifically, we hypothesized that there may be a deficit in the mirror neuron system (MNS), a neural system that responds to both performed and observed actions. Using functional MRI, 14 boys with DCD (x=10.08 years ± 1.31, range=7.83-11.58 years) and 12 typically developing controls (x=10.10 years ± 1.15, range=8.33-12.00 years) were scanned observing, executing and imitating a finger sequencing task using their right hand. Cortical activations of mirror neuron regions, including posterior inferior frontal gyrus (IFG), ventral premotor cortex, anterior inferior parietal lobule and superior temporal sulcus were examined. Children with DCD had decreased cortical activation mirror neuron related regions, including the precentral gyrus and IFG, as well as in the posterior cingulate and precuneus complex when observing the sequencing task. Region of interest analysis revealed lower activation in the pars opercularis, a primary MNS region, during imitation in the DCD group compared to controls. These findings provide some preliminary evidence to support a possible MNS dysfunction in children with DCD.

  4. Cortical activation during power grip task with pneumatic pressure gauge: an fMRI study

    Science.gov (United States)

    Mohamad, M.; Mardan, N. H.; Ismail, S. S.

    2017-05-01

    Aging is associated with a decline in cognitive and motor function. But, the relationships with motor performance are less well understood. In this study, functional magnetic resonance imaging (fMRI) was used to assess cortical activation in older adults. This study employed power grip task that utilised block paradigm consisted of alternate 30s rest and active. A visual cue was used to pace the hand grip movement that clenched a cylindrical rubber bulb connected with pressure pneumatic gauge that measure the pressure (Psi). The objective of this study is determined the brain areas activated during motor task and the correlation between percentage signal change of each motor area (BA 4 and 6) and hand grip pressure. Result showed there was a significant difference in mean percentage signal change in BA 4 and BA 6 in both hemispheres and negative correlation obtained in BA 4 and BA 6. These results indicate that a reduced ability in the motor networks contribute to age-related decline in motor performance.

  5. Brain's reward circuits mediate itch relief. a functional MRI study of active scratching.

    Directory of Open Access Journals (Sweden)

    Alexandru D P Papoiu

    Full Text Available Previous brain imaging studies investigating the brain processing of scratching used an exogenous intervention mimicking scratching, performed not by the subjects themselves, but delivered by an investigator. In real life, scratching is a conscious, voluntary, controlled motor response to itching, which is directed to the perceived site of distress. In this study we aimed to visualize in real-time by brain imaging the core mechanisms of the itch-scratch cycle when scratching was performed by subjects themselves. Secondly, we aimed to assess the correlations between brain patterns of activation and psychophysical ratings of itch relief or pleasurability of scratching. We also compared the patterns of brain activity evoked by self-scratching vs. passive scratching. We used a robust tridimensional Arterial Spin Labeling fMRI technique that is less sensitive to motion artifacts: 3D gradient echo and spin echo (GRASE--Propeller. Active scratching was accompanied by a higher pleasurability and induced a more pronounced deactivation of the anterior cingulate cortex and insula, in comparison with passive scratching. A significant involvement of the reward system including the ventral tegmentum of the midbrain, coupled with a mechanism deactivating the periaqueductal gray matter (PAG, suggests that itch modulation operates in reverse to the mechanism known to suppress pain. Our findings not only confirm a role for the central networks processing reward in the pleasurable aspects of scratching, but also suggest they play a role in mediating itch relief.

  6. Effects of active music therapy on the normal brain: fMRI based evidence.

    Science.gov (United States)

    Raglio, Alfredo; Galandra, Caterina; Sibilla, Luisella; Esposito, Fabrizio; Gaeta, Francesca; Di Salle, Francesco; Moro, Luca; Carne, Irene; Bastianello, Stefano; Baldi, Maurizia; Imbriani, Marcello

    2016-03-01

    The aim of this study was to investigate the neurophysiological bases of Active Music Therapy (AMT) and its effects on the normal brain. Twelve right-handed, healthy, non-musician volunteers were recruited. The subjects underwent 2 AMT sessions based on the free sonorous-music improvisation using rhythmic and melodic instruments. After these sessions, each subject underwent 2 fMRI scan acquisitions while listening to a Syntonic (SP) and an A-Syntonic (AP) Production from the AMT sessions. A 3 T Discovery MR750 scanner with a 16-channel phased array head coil was used, and the image analysis was performed with Brain Voyager QX 2.8. The listening to SP vs AP excerpts mainly activated: (1) the right middle temporal gyrus and right superior temporal sulcus, (2) the right middle frontal gyrus and in particular the right precentral gyrus, (3) the bilateral precuneus, (4) the left superior temporal sulcus and (5) the left middle temporal gyrus. These results are consistent with the psychological bases of the AMT approach and with the activation of brain areas involved in memory and autobiographical processes, and also in personal or interpersonal significant experiences. Further studies are required to confirm these findings and to explain possible effects of AMT in clinical settings.

  7. Subjective feeling of appetite modulates brain activity: an fMRI study.

    Science.gov (United States)

    Porubská, Katarína; Veit, Ralf; Preissl, Hubert; Fritsche, Andreas; Birbaumer, Niels

    2006-09-01

    Obesity and overweight are important risk factors for the development of diabetes mellitus type 2 and associated chronic diseases, and therefore, they have become serious global problems in the western and developed countries. But little is known about the neuroanatomical correlates of eating behavior and its influences on the central nervous processing in humans. We used functional magnetic resonance imaging (fMRI) to measure the cortical activation in 12 lean healthy humans during visual stimulation with food-related and nonfood pictures after a fasting period of at least 5 h. Compared to the nonfood pictures, the food stimuli elicited a significantly greater activity in the left orbitofrontal cortex and the insular/opercular cortex bilaterally with a stronger focus on the left side. Subjective ratings of appetite during the presentation of food-related stimuli modulated the activity in the insula bilaterally, the left operculum and the right putamen. These results provide further insights in the central nervous processing of food relevant stimuli in humans, specifically with respect to the subjective experience of appetite.

  8. Application study of activity-based costing management in MRI cost accounting%作业成本法在 MRI 项目成本测算中的应用研究

    Institute of Scientific and Technical Information of China (English)

    苏樱华; 黄耀渠

    2014-01-01

    To investigate the feasibility and value of activity-based costing (ABC)method in calculating unit cost of different MRI items. Taking a MRI center as the cost object, the theory and method of ABC was used to calculate unit cost of different MRI items, and compared with the conventional cost measurement method. The unit cost of MRI plain scan, MRI contrast enhancement, and MR angiography was 509.81 yuan,649.62 yuan, and 1020.51 yuan respectively by using ABC method, the results were different with conventional cost measurement method. This study shows that the ABC management in MRI cost accounting is feasible, and can have more detailed and precise estimate of indirect cost than conventional cost measurement method.%目的:探讨采用作业成本法测算 MRI 项目单位成本的可行性和价值。方法运用作业成本法理论与方法,以某医院 MRI 中心项目为成本对象,测算不同 MRI 项目的单位成本,并与传统成本测算方法进行比较。结果作业成本法测算出 MR 平扫、增强扫描及血管造影项目的成本分别为509.81元、649.62元、1020.51元,其结果与传统成本核算方法存在差异。结论作业成本法测算 MRI 项目成本是可行的,并且较传统成本方法更详细、准确反映间接成本的构成情况。

  9. Compensatory cortical activation observed by fMRI during a cognitive task at the earliest stage of MS.

    Science.gov (United States)

    Audoin, Bertrand; Ibarrola, Danielle; Ranjeva, Jean-Philippe; Confort-Gouny, Sylviane; Malikova, Irina; Ali-Chérif, André; Pelletier, Jean; Cozzone, Patrick

    2003-10-01

    Recent functional magnetic resonance imaging (fMRI) studies have suggested that functional cortical changes seen in patients with early relapsing-remitting multiple sclerosis (MS) can have an adaptive role to limit the clinical impact of tissue injury. To determine whether cortical reorganization occurs during high cognitive processes at the earliest stage of multiple sclerosis (MS), we performed an fMRI experiment using the conventional Paced Auditory Serial Addition Test (PASAT) as paradigm in a population of ten patients with clinically isolated syndrome suggestive of multiple sclerosis (CISSMS). At the time of the fMRI exploration, mean disease duration was 6.8 +/- 3.3 months. We compared these results to those obtained in a group of ten education-, age-, and sex-matched healthy controls. Subjects were explored on a 1.5 T MRI system using single-shot gradient-echo EPI sequence. Performances of the two groups during PASAT recorded inside the MR scanner were not different. Statistical assessment of brain activation was based on the random effect analysis (between-group analysis two-sample t-test P < 0.005 confirmed by individual analyses performed in the surviving regions P < 0.05 Mann Whitney U-test). Compared to controls, patients showed significantly greater activation in the right frontopolar cortex, the bilateral lateral prefrontal cortices, and the right cerebellum. Healthy controls did not show greater activation compared to CISSMS patients. The present study argues in favor of the existence of compensatory cortical activations at the earliest stage of MS mainly located in regions involved in executive processing in patients performing PASAT. It also suggests that fMRI can evidence the active processes of neuroplasticity contributing to mask the clinical cognitive expression of brain pathology at the earliest stage of MS.

  10. Active waveguides produced in lithium fluoride by He{sup +} implantation

    Energy Technology Data Exchange (ETDEWEB)

    Mussi, V. [Dip. Fisica and UdR INFM, Universita di Genova, V. Dodecaneso 33, 16146 Genova (Italy)]. E-mail: mussi@fisica.unige.it; Montereali, R.M. [ENEA, Advanced Physical Technologies, C.R. Frascati, V.E. Fermi 45, 00044 Frascati (Italy); Moretti, P. [LPCML, UMR 5620, CNRS Universite Lyon 1, 69622 Villeurbanne (France); Mugnier, J. [LPCML, UMR 5620, CNRS Universite Lyon 1, 69622 Villeurbanne (France); Nichelatti, E. [ENEA, Advanced Physical Technologies, C.R. Casaccia, V. Anguillarese 301, 00060 Rome (Italy); Somma, F. [Dip. Fis. and UdR INFM, Universita Roma Tre, V. della Vasca Navale 84, 00146 Rome (Italy); Jacquier, B. [LPCML, UMR 5620, CNRS Universite Lyon 1, 69622 Villeurbanne (France)

    2005-04-01

    Planar active waveguides were produced in lithium fluoride crystals by implantation with 1.5 MeV He{sup +} ions at several doses. The colored samples have been characterized by optical absorption, photoluminescence and m-line spectroscopy. By comparing the measured guided-mode effective indices with the ones calculated by means of the Chandler-Lama approach, the depth profile of refractive index was derived, showing that there are two competitive physical mechanisms, associated with different processes of energy deposition along the ion track, responsible for positive and negative modifications of the refractive index in the irradiated volume.

  11. Laser fabrication of electrical feedthroughs in polymer encapsulations for active implantable medical devices.

    Science.gov (United States)

    Gough, Zara; Chaminade, Cedric; Barclay-Monteith, Philip; Kallinen, Annukka; Lei, Wenwen; Ganesan, Rajesh; Grace, John; McKenzie, David R

    2017-01-31

    Hermetic electrical feedthroughs are essential for safe and functional active implantable biomedical devices and for a wide range of other applications such as batteries, supercapacitors, OLEDs and solar cells. Ceramics and metals have previously been the materials of choice for encapsulations, while polymers have advantages of ease of mass production and end user compatibility. We demonstrate a laser sealing technology that gives hermetic, mechanically strong feedthroughs with low electrical resistance in a polyetheretherketone (PEEK) encapsulation. The conductive pathways are wires and sputtered thin films. The water vapor transmission rate through the fabricated encapsulations is comparable to that of PEEK itself.

  12. How does an fMRI voxel sample the neuronal activity pattern: compact-kernel or complex spatiotemporal filter?

    Science.gov (United States)

    Kriegeskorte, Nikolaus; Cusack, Rhodri; Bandettini, Peter

    2010-02-01

    Recent studies suggested that fMRI voxel patterns can convey information represented in columnar-scale neuronal population codes, even when spatial resolution is insufficient to directly image the patterns of columnar selectivity (Kamitani and Tong, 2005; Haynes and Rees, 2005). Sensitivity to subvoxel-scale pattern information, or "fMRI hyperacuity," would greatly enhance the power of fMRI when combined with pattern information analysis techniques (Kriegeskorte and Bandettini, 2007). An individual voxel might weakly reflect columnar-level information if the columns within its boundaries constituted a slightly unbalanced sample of columnar selectivities (Kamitani and Tong, 2005), providing a possible mechanism for fMRI hyperacuity. However, Op de Beeck (2009) suggests that a coarse-scale neuronal organization rather than fMRI hyperacuity may explain the presence of the information in the fMRI patterns. Here we argue (a) that the present evidence does not rule out fMRI hyperacuity, (b) that the mechanism originally suggested for fMRI hyperacuity (biased sampling by averaging within each voxel's boundaries; Kamitani and Tong, 2005) will only produce very weak sensitivity to fine-grained pattern information, and (c) that an alternative mechanism (voxel as complex spatiotemporal filter) is physiologically more accurate and promises stronger sensitivity to fine-grained pattern information: We know that each voxel samples the neuronal activity pattern through a unique fine-grained structure of venous vessels that supply its blood oxygen level-dependent signal. At the simplest level, the drainage domain of a venous vessel may sample the neuronal pattern with a selectivity bias (Gardner, 2009; Shmuel et al., 2009). Beyond biased drainage domains, we illustrate with a simple simulation how temporal properties of the hemodynamics (e.g., the speed of the blood in the capillary bed) can shape spatial properties of a voxel's filter (e.g., how finely structured it is). This

  13. fMRI activation in relation to sound intensity and loudness

    NARCIS (Netherlands)

    Langers, Dave R. M.; van Dijk, Pirn; Schoemaker, Esther S.; Backes, Walter H.

    2007-01-01

    The aim of this fMRI study was to relate cortical fMRI responses to both physical and perceptual sound level characteristics. Besides subjects with normal hearing, subjects with high-frequency sensorineural hearing loss were included, as distortion of loudness perception is a characteristic of such

  14. 3D-EAUS and MRI in the Activity of Anal Fistulas in Crohn's Disease.

    Science.gov (United States)

    Alabiso, Maria Eleonora; Iasiello, Francesca; Pellino, Gianluca; Iacomino, Aniello; Roberto, Luca; Pinto, Antonio; Riegler, Gabriele; Selvaggi, Francesco; Reginelli, Alfonso

    2016-01-01

    Aim. This study aspires to assess the role of 3D-Endoanal Ultrasound (3D-EAUS) and Magnetic Resonance Imaging (MRI) in preoperative evaluation of the primary tract and internal opening of perianal fistulas, of secondary extensions and abscess. Methods. During 2014, 51 Crohn's disease patients suspected for perianal fistula were enrolled. All patients underwent physical examination with both the methods and subsequent surgery. Results. In the evaluation of CD perianal fistulas, there are no significant differences between 3D-EAUS and MRI in the identification of abscess and secondary extension. Considering the location, 3D-EAUS was more accurate than MRI in the detection of intersphincteric fistulas (p value = 10(-6)); conversely, MRI was more accurate than 3D-EAUS in the detection of suprasphincteric fistulas (p value = 0.0327) and extrasphincteric fistulas (p  value = 4 ⊕ 10(-6)); there was no significant difference between MRI and 3D-EAUS in the detection of transsphincteric fistulas. Conclusions. Both 3D-EAUS and MRI have a crucial role in the evaluation and detection of CD perianal fistulas. 3D-EAUS was preferable to MRI in the detection of intersphincteric fistulas; conversely, in the evaluation of suprasphincteric and extrasphincteric fistulas the MRI was preferable to 3D-EAUS.

  15. Extendable supervised dictionary learning for exploring diverse and concurrent brain activities in task-based fMRI.

    Science.gov (United States)

    Zhao, Shijie; Han, Junwei; Hu, Xintao; Jiang, Xi; Lv, Jinglei; Zhang, Tuo; Zhang, Shu; Guo, Lei; Liu, Tianming

    2017-06-09

    Recently, a growing body of studies have demonstrated the simultaneous existence of diverse brain activities, e.g., task-evoked dominant response activities, delayed response activities and intrinsic brain activities, under specific task conditions. However, current dominant task-based functional magnetic resonance imaging (tfMRI) analysis approach, i.e., the general linear model (GLM), might have difficulty in discovering those diverse and concurrent brain responses sufficiently. This subtraction-based model-driven approach focuses on the brain activities evoked directly from the task paradigm, thus likely overlooks other possible concurrent brain activities evoked during the information processing. To deal with this problem, in this paper, we propose a novel hybrid framework, called extendable supervised dictionary learning (E-SDL), to explore diverse and concurrent brain activities under task conditions. A critical difference between E-SDL framework and previous methods is that we systematically extend the basic task paradigm regressor into meaningful regressor groups to account for possible regressor variation during the information processing procedure in the brain. Applications of the proposed framework on five independent and publicly available tfMRI datasets from human connectome project (HCP) simultaneously revealed more meaningful group-wise consistent task-evoked networks and common intrinsic connectivity networks (ICNs). These results demonstrate the advantage of the proposed framework in identifying the diversity of concurrent brain activities in tfMRI datasets.

  16. Towards quantification of blood-flow changes during cognitive task activation using perfusion-based fMRI.

    Science.gov (United States)

    Mildner, Toralf; Zysset, Stefan; Trampel, Robert; Driesel, Wolfgang; Möller, Harald E

    2005-10-01

    Multi-slice perfusion-based functional magnetic resonance imaging (p-fMRI) is demonstrated with a color-word Stroop task as an established cognitive paradigm. Continuous arterial spin labeling (CASL) of the blood in the left common carotid artery was applied for all repetitions of the functional run in a quasi-continuous fashion, i.e., it was interrupted only during image acquisition. For comparison, blood oxygen level dependent (BOLD) contrast was detected using conventional gradient-recalled echo (GE) echo planar imaging (EPI). Positive activations in BOLD imaging appeared in p-fMRI as negative signal changes corresponding to an enhanced transport of inverted water spins into the region of interest, i.e., increased cerebral blood flow (CBF). Regional differences between the localization of activations and the sensitivity of p-fMRI and BOLD-fMRI were observed as, for example, in the inferior frontal sulcus and in the intraparietal sulcus. Quantification of CBF changes during cognitive task activation was performed on a multi-subject basis and yielded CBF increases of the order of 20-30%.

  17. Activation of sensory cortex by imagined genital stimulation: an fMRI analysis

    Science.gov (United States)

    Wise, Nan J.; Frangos, Eleni; Komisaruk, Barry R.

    2016-01-01

    Background During the course of a previous study, our laboratory made a serendipitous finding that just thinking about genital stimulation resulted in brain activations that overlapped with, and differed from, those generated by physical genital stimulation. Objective This study extends our previous findings by further characterizing how the brain differentially processes physical ‘touch’ stimulation and ‘imagined’ stimulation. Design Eleven healthy women (age range 29–74) participated in an fMRI study of the brain response to imagined or actual tactile stimulation of the nipple and clitoris. Two additional conditions – imagined dildo self-stimulation and imagined speculum stimulation – were included to characterize the effects of erotic versus non-erotic imagery. Results Imagined and tactile self-stimulation of the nipple and clitoris each activated the paracentral lobule (the genital region of the primary sensory cortex) and the secondary somatosensory cortex. Imagined self-stimulation of the clitoris and nipple resulted in greater activation of the frontal pole and orbital frontal cortex compared to tactile self-stimulation of these two bodily regions. Tactile self-stimulation of the clitoris and nipple activated the cerebellum, primary somatosensory cortex (hand region), and premotor cortex more than the imagined stimulation of these body regions. Imagining dildo stimulation generated extensive brain activation in the genital sensory cortex, secondary somatosensory cortex, hippocampus, amygdala, insula, nucleus accumbens, and medial prefrontal cortex, whereas imagining speculum stimulation generated only minimal activation. Conclusion The present findings provide evidence of the potency of imagined stimulation of the genitals and that the following brain regions may participate in erogenous experience: primary and secondary sensory cortices, sensory-motor integration areas, limbic structures, and components of the ‘reward system’. In addition

  18. Activation of sensory cortex by imagined genital stimulation: an fMRI analysis

    Directory of Open Access Journals (Sweden)

    Nan J. Wise

    2016-10-01

    Full Text Available Background: During the course of a previous study, our laboratory made a serendipitous finding that just thinking about genital stimulation resulted in brain activations that overlapped with, and differed from, those generated by physical genital stimulation. Objective: This study extends our previous findings by further characterizing how the brain differentially processes physical ‘touch’ stimulation and ‘imagined’ stimulation. Design: Eleven healthy women (age range 29–74 participated in an fMRI study of the brain response to imagined or actual tactile stimulation of the nipple and clitoris. Two additional conditions – imagined dildo self-stimulation and imagined speculum stimulation – were included to characterize the effects of erotic versus non-erotic imagery. Results: Imagined and tactile self-stimulation of the nipple and clitoris each activated the paracentral lobule (the genital region of the primary sensory cortex and the secondary somatosensory cortex. Imagined self-stimulation of the clitoris and nipple resulted in greater activation of the frontal pole and orbital frontal cortex compared to tactile self-stimulation of these two bodily regions. Tactile self-stimulation of the clitoris and nipple activated the cerebellum, primary somatosensory cortex (hand region, and premotor cortex more than the imagined stimulation of these body regions. Imagining dildo stimulation generated extensive brain activation in the genital sensory cortex, secondary somatosensory cortex, hippocampus, amygdala, insula, nucleus accumbens, and medial prefrontal cortex, whereas imagining speculum stimulation generated only minimal activation. Conclusion: The present findings provide evidence of the potency of imagined stimulation of the genitals and that the following brain regions may participate in erogenous experience: primary and secondary sensory cortices, sensory-motor integration areas, limbic structures, and components of the

  19. Optical activity and defect/dopant evolution in ZnO implanted with Er

    Energy Technology Data Exchange (ETDEWEB)

    Azarov, Alexander; Galeckas, Augustinas; Kuznetsov, Andrej; Monakhov, Edouard; Svensson, Bengt G. [Department of Physics, Centre for Materials Science and Nanotechnology, University of Oslo, P.O. Box 1048, Blindern, N-0316 Oslo (Norway); Hallén, Anders [Royal Institute of Technology, KTH-ICT, Electrum 229, SE-164 40 Stockholm (Sweden)

    2015-09-28

    The effects of annealing on the optical properties and defect/dopant evolution in wurtzite (0001) ZnO single crystals implanted with Er ions are studied using a combination of Rutherford backscattering/channeling spectrometry and photoluminescence measurements. The results suggest a lattice recovery behavior dependent on ion dose and involving formation/evolution of an anomalous multipeak defect distribution, thermal stability of optically active Er complexes, and Er outdiffusion. An intermediate defect band occurring between the surface and ion-induced defects in the bulk is stable up to 900 °C and has a photoluminescence signature around 420 nm well corresponding to Zn interstitials. The optical activity of the Er atoms reaches a maximum after annealing at 700 °C but is not directly associated to the ideal Zn site configuration, since the Er substitutional fraction is maximal already in the as-implanted state. In its turn, annealing at temperatures above 700 °C leads to dissociation of the optically active Er complexes with subsequent outdiffusion of Er accompanied by the efficient lattice recovery.

  20. Application of fMRI to obesity research: differences in reward pathway activation measured with fMRI BOLD during visual presentation of high and low calorie foods

    Science.gov (United States)

    Tsao, Sinchai; Adam, Tanja C.; Goran, Michael I.; Singh, Manbir

    2012-03-01

    The factors behind the neural mechanisms that motivate food choice and obesity are not well known. Furthermore, it is not known when these neural mechanisms develop and how they are influenced by both genetic and environmental factors. This study uses fMRI together with clinical data to shed light on the aforementioned questions by investigating how appetite-related activation in the brain changes with low versus high caloric foods in pre-pubescent girls. Previous studies have shown that obese adults have less striatal D2 receptors and thus reduced Dopamine (DA) signaling leading to the reward-deficit theory of obesity. However, overeating in itself reduces D2 receptor density, D2 sensitivity and thus reward sensitivity. The results of this study will show how early these neural mechanisms develop and what effect the drastic endocrinological changes during puberty has on these mechanisms. Our preliminary results showed increased activations in the Putamen, Insula, Thalamus and Hippocampus when looking at activations where High Calorie > Low Calorie. When comparing High Calorie > Control and Low Calorie > Control, the High > Control test showed increased significant activation in the frontal lobe. The Low > Control also yielded significant activation in the Left and Right Fusiform Gyrus, which did not appear in the High > Control test. These results indicate that the reward pathway activations previously shown in post-puberty and adults are present in pre-pubescent teens. These results may suggest that some of the preferential neural mechanisms of reward are already present pre-puberty.

  1. Neural Activations of Guided Imagery and Music in Negative Emotional Processing: A Functional MRI Study.

    Science.gov (United States)

    Lee, Sang Eun; Han, Yeji; Park, HyunWook

    2016-01-01

    The Bonny Method of Guided Imagery and Music uses music and imagery to access and explore personal emotions associated with episodic memories. Understanding the neural mechanism of guided imagery and music (GIM) as combined stimuli for emotional processing informs clinical application. We performed functional magnetic resonance imaging (fMRI) to demonstrate neural mechanisms of GIM for negative emotional processing when personal episodic memory is recalled and re-experienced through GIM processes. Twenty-four healthy volunteers participated in the study, which used classical music and verbal instruction stimuli to evoke negative emotions. To analyze the neural mechanism, activated regions associated with negative emotional and episodic memory processing were extracted by conducting volume analyses for the contrast between GIM and guided imagery (GI) or music (M). The GIM stimuli showed increased activation over the M-only stimuli in five neural regions associated with negative emotional and episodic memory processing, including the left amygdala, left anterior cingulate gyrus, left insula, bilateral culmen, and left angular gyrus (AG). Compared with GI alone, GIM showed increased activation in three regions associated with episodic memory processing in the emotional context, including the right posterior cingulate gyrus, bilateral parahippocampal gyrus, and AG. No neural regions related to negative emotional and episodic memory processing showed more activation for M and GI than for GIM. As a combined multimodal stimulus, GIM may increase neural activations related to negative emotions and episodic memory processing. Findings suggest a neural basis for GIM with personal episodic memories affecting cortical and subcortical structures and functions. © the American Music Therapy Association 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  2. Selection of a Model of Cerebral Activity for fMRI Group Data Analysis

    CERN Document Server

    Keller, Merlin; Lavielle, Marc

    2010-01-01

    This thesis is dedicated to the statistical analysis of multi-sub ject fMRI data, with the purpose of identifying bain structures involved in certain cognitive or sensori-motor tasks, in a reproducible way across sub jects. To overcome certain limitations of standard voxel-based testing methods, as implemented in the Statistical Parametric Mapping (SPM) software, we introduce a Bayesian model selection approach to this problem, meaning that the most probable model of cerebral activity given the data is selected from a pre-defined collection of possible models. Based on a parcellation of the brain volume into functionally homogeneous regions, each model corresponds to a partition of the regions into those involved in the task under study and those inactive. This allows to incorporate prior information, and avoids the dependence of the SPM-like approach on an arbitrary threshold, called the cluster- forming threshold, to define active regions. By controlling a Bayesian risk, our approach balances false positive...

  3. Aggression by ovariectomized female rats with testosterone implants: competitive experience activates aggression toward unfamiliar females.

    Science.gov (United States)

    Albert, D J; Jonik, R H; Walsh, M L

    1990-04-01

    Female hooded rats (250 to 325 g) were ovariectomized and bilaterally implanted with testosterone-filled or empty Silastic tubes. The testosterone-filled space in each tube was 10 mm long and this should produce a serum testosterone concentration 4 to 5 times that of an intact female, but well below that of a male. Three weeks following surgery, half of the animals with testosterone implants were housed with an animal with an empty implant and left for 6 weeks. The remaining animals were placed on a 23-hr food deprivation schedule, housed in testosterone implant/empty implant pairs, and then subjected to a series of food competition tests. Following the competition tests, all animals were individually tested in their living cage for aggression toward an unfamiliar female. In food competition, females with testosterone implants were more successful and more aggressive than their cagemates with empty implants. When tested for aggression toward an unfamiliar intruder, females with testosterone implants given competitive experience were more aggressive toward an intruder than were their cagemates with empty implants or females with testosterone implants not given the competitive experience. Females with testosterone implants but without competitive experience were not more aggressive toward an unfamiliar female than were their cagemates with empty implants. These results suggest that, in ovariectomized females with testosterone implants, hormone-dependent aggression fostered by a competitive situation is displayed toward unfamiliar females.

  4. Transient brain activity disentangles fMRI resting-state dynamics in terms of spatially and temporally overlapping networks.

    Science.gov (United States)

    Karahanoğlu, Fikret Işik; Van De Ville, Dimitri

    2015-07-16

    Dynamics of resting-state functional magnetic resonance imaging (fMRI) provide a new window onto the organizational principles of brain function. Using state-of-the-art signal processing techniques, we extract innovation-driven co-activation patterns (iCAPs) from resting-state fMRI. The iCAPs' maps are spatially overlapping and their sustained-activity signals temporally overlapping. Decomposing resting-state fMRI using iCAPs reveals the rich spatiotemporal structure of functional components that dynamically assemble known resting-state networks. The temporal overlap between iCAPs is substantial; typically, three to four iCAPs occur simultaneously in combinations that are consistent with their behaviour profiles. In contrast to conventional connectivity analysis, which suggests a negative correlation between fluctuations in the default-mode network (DMN) and task-positive networks, we instead find evidence for two DMN-related iCAPs consisting the posterior cingulate cortex that differentially interact with the attention network. These findings demonstrate how the fMRI resting state can be functionally decomposed into spatially and temporally overlapping building blocks using iCAPs.

  5. The effects of aging on the brain activation pattern during a speech perception task: an fMRI study.

    Science.gov (United States)

    Manan, Hanani Abdul; Franz, Elizabeth A; Yusoff, Ahmad Nazlim; Mukari, Siti Zamratol-Mai Sarah

    2015-02-01

    In the present study, brain activation associated with speech perception processing was examined across four groups of adult participants with age ranges between 20 and 65 years, using functional MRI (fMRI). Cognitive performance demonstrates that performance accuracy declines with age. fMRI results reveal that all four groups of participants activated the same brain areas. The same brain activation pattern was found in all activated areas (except for the right superior temporal gyrus and right middle temporal gyrus); brain activity was increased from group 1 (20-29 years) to group 2 (30-39 years). However, it decreased in group 3 (40-49 years) with further decreases in group 4 participants (50-65 years). Result also reveals that three brain areas (superior temporal gyrus, Heschl's gyrus and cerebellum) showed changes in brain laterality in the older participants, akin to a shift from left-lateralized to right-lateralized activity. The onset of this change was different across brain areas. Based on these findings we suggest that, whereas all four groups of participants used the same areas in processing, the engagement and recruitment of those areas differ with age as the brain grows older. Findings are discussed in the context of corroborating evidence of neural changes with age.

  6. Electro active polymers : novel bio-electrodes and implants for urinary continence

    Energy Technology Data Exchange (ETDEWEB)

    Rajagopalan, S.; Sawan, M.; Savadogo, O. [Ecole Polytechnique, Montreal, PQ (Canada). Laboratoire de nouveaux materiaux pour les systemes electrochimiques et energetiques

    2006-07-01

    This paper presented a technical solution to spinal cord injuries that result in urinary bladder dysfunction. It involves miniaturized implants based on polypyrrole, an electroactive polymer, as smart drug-eluting electrodes for neural stimulation to restore bladder function. The nerve-electrode interface is the most vulnerable point in the design and operation of neuro-electronic implants. The main disadvantages are decreased impedance and protein build-up at the stimulation site due to an inflammatory reaction. Polypyrrole is a naturally conducting polymer having both electron-conducting properties as well as actuating properties, rendering it suitable as a drug-eluting electrode for a neurostimulator. Polypyrrole electrochemically coated on platinum increases biocompatibility and reduces electric impedance by increasing the surface area of the electrode. When electrically stimulated, polypyrrole also serves as a matrix to release a negatively-charged anti-inflammatory drug fosfosal. This technology may prove useful in reconstructing a severely damaged bladder through electroactive biomaterials. Polyelectrolyte gels, such as poly(sodium) acrylate, reversibly contract and relax when activated electrically or under the influx of divalent ions. These artificial muscles can be connected to a polypyrrole strain sensor to alert the microcontroller to activate the sphincter muscle, thereby creating an artificial bladder.

  7. Noninvasive activity-based control of an implantable rotary blood pump: comparative software simulation study.

    Science.gov (United States)

    Karantonis, Dean M; Lim, Einly; Mason, David G; Salamonsen, Robert F; Ayre, Peter J; Lovell, Nigel H

    2010-02-01

    A control algorithm for an implantable centrifugal rotary blood pump (RBP) based on a noninvasive indicator of the implant recipient's activity level has been proposed and evaluated in a software simulation environment. An activity level index (ALI)-derived from a noninvasive estimate of heart rate and the output of a triaxial accelerometer-forms the noninvasive indicator of metabolic energy expenditure. Pump speed is then varied linearly according to the ALI within a defined range. This ALI-based control module operates within a hierarchical multiobjective framework, which imposes several constraints on the operating region, such as minimum flow and minimum speed amplitude thresholds. Three class IV heart failure (HF) cases of varying severity were simulated under rest and exercise conditions, and a comparison with other popular RBP control strategies was performed. Pump flow increases of 2.54, 1.94, and 1.15 L/min were achieved for the three HF cases, from rest to exercise. Compared with constant speed control, this represents a relative flow change of 30.3, 19.8, and -15.4%, respectively. Simulations of the proposed control algorithm exhibited the effective intervention of each constraint, resulting in an improved flow response and the maintenance of a safe operating condition, compared with other control modes.

  8. Abnormal baseline brain activity in patients with neuromyelitis optica: A resting-state fMRI study

    Energy Technology Data Exchange (ETDEWEB)

    Liu Yaou [Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing 100053 (China); Liang Peipeng [Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing 100053 (China); International WIC institute, Beijing University of Technology, Beijing 100024 (China); Duan Yunyun; Jia Xiuqin; Wang Fei; Yu Chunshui; Qin Wen [Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing 100053 (China); Dong Huiqing; Ye Jing [Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing 100053 (China); Li Kuncheng, E-mail: likuncheng1955@yahoo.com.cn [Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing 100053 (China)

    2011-11-15

    Purpose: Recent immunopathologic and MRI findings suggest that tissue damage in neuromyelitis optica (NMO) is not limited to spinal cord and optic nerve, but also in brain. Baseline brain activity can reveal the brain functional changes to the tissue damages and give clues to the pathophysiology of NMO, however, it has never been explored by resting-state functional MRI (fMRI). We used regional amplitude of low frequency fluctuation (ALFF) as an index in resting-state fMRI to investigate how baseline brain activity changes in patients with NMO. Methods: Resting-state fMRIs collected from seventeen NMO patients and seventeen age- and sex-matched normal controls were compared to investigate the ALFF difference between the two groups. The relationships between ALFF in regions with significant group differences and the EDSS (Expanded Disability Status Scale), disease duration were further explored. Results: Our results showed that NMO patients had significantly decreased ALFF in precuneus, posterior cingulate cortex (PCC) and lingual gyrus; and increased ALFF in middle frontal gyrus, caudate nucleus and thalamus, compared to normal controls. Moderate negative correlations were found between the EDSS and ALFF in the left middle frontal gyrus (r = -0.436, p = 0.040) and the left caudate (r = -0.542, p = 0.012). Conclusion: The abnormal baseline brain activity shown by resting-state fMRI in NMO is relevant to cognition, visual and motor systems. It implicates a complex baseline brain status of both functional impairments and adaptations caused by tissue damages in these systems, which gives clues to the pathophysiology of NMO.

  9. Modulation of functionally localized right insular cortex activity using real-time fMRI-based neurofeedback

    Directory of Open Access Journals (Sweden)

    Brian D Berman

    2013-10-01

    Full Text Available The capacity for subjects to learn to volitionally control localized brain activity using neurofeedback is actively being investigated. We aimed to investigate the ability of healthy volunteers to quickly learn to use visual feedback during real-time functional MRI (rtfMRI to modulate brain activity within their anterior right insular cortex (RIC localized during a blink suppression task, an approach of possible interest in the use of rtfMRI to reduce urges. The RIC region of interest (RIC-ROI was functionally localized using a blink suppression task, and BOLD signal changes within RIC-ROI used to create a constantly updating display fed back to the subject in the scanner. Subjects were instructed to use emotional imagery to try and increase activity within RIC-ROI during four feedback training runs (FB1–FB4. A ‘control’ run (CNTRL before training and a ‘transfer’ run (XSFR after training were performed without feedback to assess for baseline abilities and learning effects. Fourteen participants completed all neurofeedback training runs. At the group level, increased BOLD activity was seen in the anterior RIC during all the FB runs, but a significant increase in the functionally defined RIC-ROI was only attained during FB2. In atlas-defined insular cortex ROIs, significant increases were seen bilaterally during the CNTRL, FB1, FB2, and FB4 runs. Increased activity within the insular cortices did not show lateralization. Training did, however, result in a significant increase in functional connectivity between the RIC-ROI and the medial frontal gyrus when comparing FB4 to FB1. Since neurofeedback training did not lead to an increase in BOLD signal across all feedback runs, we suggest that learning to control one’s brain activity in this fashion may require longer or repeated rtfMRI training sessions.

  10. Long-term effects of secukinumab on MRI findings in relation to clinical efficacy in subjects with active ankylosing spondylitis : An observational study

    NARCIS (Netherlands)

    Baraliakos, Xenofon; Borah, Babul; Braun, Juergen; Baeten, Dominique; Laurent, Didier; Sieper, Joachim; Emery, Paul; McInnes, Iain B.; van Laar, Jacob M.; Wordsworth, Paul; Wollenhaupt, Juergen; Kellner, Herbert; Colin, Laurence; Vandenhende, Francois; Radford, Kath; Hueber, Wolfgang

    2016-01-01

    Introduction A 28-week study suggested efficacy of the anti-interleukin-17A monoclonal antibody secukinumab in active ankylosing spondylitis (AS). MRI-assessed inflammation was reduced at weeks 6, 28. Objective To analyse the longer-term effects of secukinumab on MRI inflammatory and non-inflammator

  11. Baseline brain activity changes in patients with clinically isolated syndrome revealed by resting-state functional MRI

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yaou; Duan, Yunyun; Liang, Peipeng; Jia, Xiuqin; Yu, Chunshui [Dept. of Radiology, Xuanwu Hospital, Capital Medical Univ., Beijing (China); Ye, Jing [Dept. of Neurology, Xuanwu Hospital, Capital Medical Univ., Beijing (China); Butzkueven, Helmut [Dept. of Medicine, Univ. of Melbourne, Melbourne (Australia); Dong, Huiqing [Dept. of Neurology, Xuanwu Hospital, Capital Medical Univ., Beijing (China); Li, Kuncheng [Dept. of Radiology, Xuanwu Hospital, Capital Medical Univ., Beijing (China); Beijing Key Laboratory of MRI and Brain Informatics, Beijing (China)], E-mail: likuncheng1955@yahoo.com.cn

    2012-11-15

    Background A clinically isolated syndrome (CIS) is the first manifestation of multiple sclerosis (MS). Previous task-related functional MRI studies demonstrate functional reorganization in patients with CIS. Purpose To assess baseline brain activity changes in patients with CIS by using the technique of regional amplitude of low frequency fluctuation (ALFF) as an index in resting-state fMRI. Material and Methods Resting-state fMRIs data acquired from 37 patients with CIS and 37 age- and sex-matched normal controls were compared to investigate ALFF differences. The relationships between ALFF in regions with significant group differences and the EDSS (Expanded Disability Status Scale), disease duration, and T2 lesion volume (T2LV) were further explored. Results Patients with CIS had significantly decreased ALFF in the right anterior cingulate cortex, right caudate, right lingual gyrus, and right cuneus (P < 0.05 corrected for multiple comparisons using Monte Carlo simulation) compared to normal controls, while no significantly increased ALFF were observed in CIS. No significant correlation was found between the EDSS, disease duration, T2LV, and ALFF in regions with significant group differences. Conclusion In patients with CIS, resting-state fMRI demonstrates decreased activity in several brain regions. These results are in contrast to patients with established MS, in whom ALFF demonstrates several regions of increased activity. It is possible that this shift from decreased activity in CIS to increased activity in MS could reflect the dynamics of cortical reorganization.

  12. Breast Implants

    Science.gov (United States)

    ... Medical Procedures Implants and Prosthetics Breast Implants Breast Implants Share Tweet Linkedin Pin it More sharing options Linkedin Pin it Email Print Breast implants are medical devices that are implanted under the ...

  13. Training readers to improve their accuracy in grading Crohn's disease activity on MRI

    Energy Technology Data Exchange (ETDEWEB)

    Tielbeek, Jeroen A.W.; Bipat, Shandra; Boellaard, Thierry N.; Nio, C.Y.; Stoker, Jaap [University of Amsterdam, Department of Radiology, Academic Medical Center, Amsterdam (Netherlands)

    2014-05-15

    To prospectively evaluate if training with direct feedback improves grading accuracy of inexperienced readers for Crohn's disease activity on magnetic resonance imaging (MRI). Thirty-one inexperienced readers assessed 25 cases as a baseline set. Subsequently, all readers received training and assessed 100 cases with direct feedback per case, randomly assigned to four sets of 25 cases. The cases in set 4 were identical to the baseline set. Grading accuracy, understaging, overstaging, mean reading times and confidence scores (scale 0-10) were compared between baseline and set 4, and between the four consecutive sets with feedback. Proportions of grading accuracy, understaging and overstaging per set were compared using logistic regression analyses. Mean reading times and confidence scores were compared by t-tests. Grading accuracy increased from 66 % (95 % CI, 56-74 %) at baseline to 75 % (95 % CI, 66-81 %) in set 4 (P = 0.003). Understaging decreased from 15 % (95 % CI, 9-23 %) to 7 % (95 % CI, 3-14 %) (P < 0.001). Overstaging did not change significantly (20 % vs 19 %). Mean reading time decreased from 6 min 37 s to 4 min 35 s (P < 0.001). Mean confidence increased from 6.90 to 7.65 (P < 0.001). During training, overall grading accuracy, understaging, mean reading times and confidence scores improved gradually. Inexperienced readers need training with at least 100 cases to achieve the literature reported grading accuracy of 75 %. (orig.)

  14. Chest MRI

    Science.gov (United States)

    Nuclear magnetic resonance - chest; Magnetic resonance imaging - chest; NMR - chest; MRI of the thorax; Thoracic MRI ... healthy enough to filter the contrast. During the MRI, the person who operates the machine will watch ...

  15. A Combined Random Forests and Active Contour Model Approach for Fully Automatic Segmentation of the Left Atrium in Volumetric MRI

    Directory of Open Access Journals (Sweden)

    Chao Ma

    2017-01-01

    Full Text Available Segmentation of the left atrium (LA from cardiac magnetic resonance imaging (MRI datasets is of great importance for image guided atrial fibrillation ablation, LA fibrosis quantification, and cardiac biophysical modelling. However, automated LA segmentation from cardiac MRI is challenging due to limited image resolution, considerable variability in anatomical structures across subjects, and dynamic motion of the heart. In this work, we propose a combined random forests (RFs and active contour model (ACM approach for fully automatic segmentation of the LA from cardiac volumetric MRI. Specifically, we employ the RFs within an autocontext scheme to effectively integrate contextual and appearance information from multisource images together for LA shape inferring. The inferred shape is then incorporated into a volume-scalable ACM for further improving the segmentation accuracy. We validated the proposed method on the cardiac volumetric MRI datasets from the STACOM 2013 and HVSMR 2016 databases and showed that it outperforms other latest automated LA segmentation methods. Validation metrics, average Dice coefficient (DC and average surface-to-surface distance (S2S, were computed as 0.9227±0.0598 and 1.14±1.205 mm, versus those of 0.6222–0.878 and 1.34–8.72 mm, obtained by other methods, respectively.

  16. A Combined Random Forests and Active Contour Model Approach for Fully Automatic Segmentation of the Left Atrium in Volumetric MRI

    Science.gov (United States)

    Luo, Gongning

    2017-01-01

    Segmentation of the left atrium (LA) from cardiac magnetic resonance imaging (MRI) datasets is of great importance for image guided atrial fibrillation ablation, LA fibrosis quantification, and cardiac biophysical modelling. However, automated LA segmentation from cardiac MRI is challenging due to limited image resolution, considerable variability in anatomical structures across subjects, and dynamic motion of the heart. In this work, we propose a combined random forests (RFs) and active contour model (ACM) approach for fully automatic segmentation of the LA from cardiac volumetric MRI. Specifically, we employ the RFs within an autocontext scheme to effectively integrate contextual and appearance information from multisource images together for LA shape inferring. The inferred shape is then incorporated into a volume-scalable ACM for further improving the segmentation accuracy. We validated the proposed method on the cardiac volumetric MRI datasets from the STACOM 2013 and HVSMR 2016 databases and showed that it outperforms other latest automated LA segmentation methods. Validation metrics, average Dice coefficient (DC) and average surface-to-surface distance (S2S), were computed as 0.9227 ± 0.0598 and 1.14 ± 1.205 mm, versus those of 0.6222–0.878 and 1.34–8.72 mm, obtained by other methods, respectively. PMID:28316992

  17. Optimization of dental implantation

    Science.gov (United States)

    Dol, Aleksandr V.; Ivanov, Dmitriy V.

    2017-02-01

    Modern dentistry can not exist without dental implantation. This work is devoted to study of the "bone-implant" system and to optimization of dental prostheses installation. Modern non-invasive methods such as MRI an 3D-scanning as well as numerical calculations and 3D-prototyping allow to optimize all of stages of dental prosthetics. An integrated approach to the planning of implant surgery can significantly reduce the risk of complications in the first few days after treatment, and throughout the period of operation of the prosthesis.

  18. Primary motor cortex activity reduction under the regulation of SMA by real-time fMRI

    Science.gov (United States)

    Guo, Jia; Zhao, Xiaojie; Li, Yi; Yao, Li; Chen, Kewei

    2012-03-01

    Real-time fMRI (rtfMRI) is a new technology which allows human subjects to observe and control their own BOLD signal change from one or more localized brain regions during scanning. Current rtfMRI-neurofeedback studies mainly focused on the target region itself without considering other related regions influenced by the real-time feedback. However, there always exits important directional influence between many of cooperative regions. On the other hand, rtfMRI based on motor imagery mainly aimed at somatomotor cortex or primary motor area, whereas supplement motor area (SMA) was a relatively more integrated and pivotal region. In this study, we investigated whether the activities of SMA can be controlled utilizing different motor imagery strategies, and whether there exists any possible impact on an unregulated but related region, primary motor cortex (M1). SMA was first localized using overt finger tapping task, the activities of SMA were feedback to subjects visually on line during each of two subsequent imagery motor movement sessions. All thirteen healthy participants were found to be able to successfully control their SMA activities by self-fit imagery strategies which involved no actual motor movements. The activation of right M1 was also found to be significantly reduced in both intensity and extent with the neurofeedback process targeted at SMA, suggestive that not only the part of motor cortex activities were influenced under the regulation of a key region SMA, but also the increased difference between SMA and M1 might reflect the potential learning effect.

  19. Feasibility of Home-Use Animal-Assisted Activities in Patients With Implanted Cardiac Electronic Devices

    Directory of Open Access Journals (Sweden)

    Peter Jirak

    2016-02-01

    Full Text Available Animal-assisted activities (AAAs are mainly carried out in institutions. The aim of this prospective pilot study was to assess the willingness of patients with cardiac implanted electronic devices (IEDs to participate in AAA. The sample included 75 ambulatory patients (18 females, M age = 69 years, who attended an outpatient clinic for control of antibradycardic pacemakers (n = 15 or implanted cardioverter defibrillators (n = 60. Twenty-three percent were current and 48% were previous pet-owners. Current pet-owners were younger than non-pet-owners (63.5 vs. 72.0 years, p = .0003. Twelve patients (16% showed interest in AAA visits. However, only two patients agreed to an AAA visit. Both patients were visited once, but declined further visits. Hence, AAA sessions at home were poorly accepted, mainly because the patients considered themselves too busy or healthy, or due to a general disinterest in AAA. Potential health benefits associated with AAA may not be feasible to investigate during home visits of AAA-teams in patients with IEDs who are healthy enough to leave their homes. For further studies concerning AAA in patients with cardiovascular diseases, we suggest focusing on institutions like rehabilitation centers or day care centers and on more severely sick, homebound patients.

  20. 人胰腺癌裸鼠皮下移植瘤模型MRI表现与病理对照研究%MRI Features and Pathology of Human Pancreatic Cancer Subcutaneously Implanted Tumor Model in Nude Mice

    Institute of Scientific and Technical Information of China (English)

    张梅花; 杨晓春; 沈钧康; 赵永华

    2015-01-01

    目的 探讨人胰腺癌裸鼠皮下移植瘤磁共振成像(MRI)检查技术及其影像学表现的病理机制.方法 建立人胰腺癌Patu8988细胞株裸鼠皮下移植瘤模型20只,细胞接种后2、4、6、7、8周随机抽取4只荷瘤鼠,进行大体观察、MRI检查和病理检查.大体观察荷瘤鼠和肿瘤的生长后进行MRI扫描,MRI平扫后,腹腔注射钆贝葡胺后4min行增强扫描,观察肿瘤影像学表现和周围组织情况;MRI检查后处死荷瘤鼠,解剖瘤灶,进行病理学研究,并与MR图像进行对照.结果 肿瘤接种成功率为100%.2周时瘤灶T1WI和T2WI信号较均匀,4~8周时瘤灶T1WI呈均匀等信号或稍高信号,T2WI呈不均匀混杂信号,增强扫描瘤灶不均匀强化,以瘤灶周缘强化明显,内可见斑片状无强化区,随着肿瘤的生长,其内无强化区逐渐扩大.结论 常规MR扫描技术能对胰腺癌皮下移植瘤的发生发展进行动态观察,移植瘤MRI表现可从病理学角度进行解释.%Objective To investigate the MRI features of human pancreatic cancer subcutaneously implanted tu-mor in nude mice and the pathomechanism of the MRI features. Methods Twenty nude mice were subcutaneously injected with human pancreatic cancer cells Patu8988 to establish the animal model. Every 4 mice were randomly sampled at 2, 4, 6, 7, and 8 weeks after inoculation of the cells to conduct gross observation, MR scanning, and pathological examination. After gross observation, the bearing tumors were scanned by MR and enhanced MR(4 min after Gd-BOPTA injection), and then the mice were sacrificed for pathological examination. MRI findings were compared with pathological findings. Results The successful rate of inoculation was 100%. The signal of two-week-old tumors showed iso-intensity on T1WI and T2WI, the signal of four- to eight-week-old tumors showed iso-intensity or slight hyper-intensity on T1WI, and mix-intensity on T2WI. The tumors were intensified at 4min postinjection of the

  1. BOLD fMRI in Infants under Sedation: Comparing the Impact of Pentobarbital and Propofol on Auditory and Language Activation

    Science.gov (United States)

    DiFrancesco, Mark W.; Robertson, Sara A.; Karunanayaka, Prasanna; Holland, Scott K.

    2013-01-01

    Purpose To elucidate differences in the disruption of language network function, as measured by BOLD fMRI, attributable to two common sedative agents administered to infants under clinical imaging protocols. Materials and Methods The sedatives pentobarbital (Nembutal) and Propofol, administered clinically to infants at one year of age, were compared with respect to BOLD activation profiles in response to passive story-listening stimulation. An intermittent event-related imaging protocol was utilized with which the temporal evolution of language processing resulting from this stimulation was explored. Results Propofol and Nembutal were found to have distinct and complementary responses to story-listening. Propofol exhibited more activation in higher processing networks with increasing response toward the end of narrative stimulus. Nembutal, in contrast, had much more robust activation of primary and secondary sensory cortices but a decreasing response over time in fronto-parietal default-mode regions. This may suggest a breakdown of top-down feedback for Propofol vs. the lack of bottom-up feed-forward processing for Nembutal. Conclusion Two popular sedative agents for use in children for clinical fMRI were found to induce distinct alteration of activation patterns from a language stimulus. This has ramifications for clinical fMRI of sedated infants and encourages further study to build a framework for more confident interpretation. PMID:23526799

  2. Implications of cortical balanced excitation and inhibition, functional heterogeneity, and sparseness of neuronal activity in fMRI

    Science.gov (United States)

    Xu, Jiansong

    2015-01-01

    Blood-oxygenation-level-dependent (BOLD) functional magnetic resonance imaging (fMRI) studies often report inconsistent findings, probably due to brain properties such as balanced excitation and inhibition and functional heterogeneity. These properties indicate that different neurons in the same voxels may show variable activities including concurrent activation and deactivation, that the relationships between BOLD signal and neural activity (i.e., neurovascular coupling) are complex, and that increased BOLD signal may reflect reduced deactivation, increased activation, or both. The traditional general-linear-model-based-analysis (GLM-BA) is a univariate approach, cannot separate different components of BOLD signal mixtures from the same voxels, and may contribute to inconsistent findings of fMRI. Spatial independent component analysis (sICA) is a multivariate approach, can separate the BOLD signal mixture from each voxel into different source signals and measure each separately, and thus may reconcile previous conflicting findings generated by GLM-BA. We propose that methods capable of separating mixed signals such as sICA should be regularly used for more accurately and completely extracting information embedded in fMRI datasets. PMID:26341939

  3. Time course of superior temporal sulcus activity in response to eye gaze: a combined fMRI and MEG study

    Science.gov (United States)

    Kochiyama, Takanori; Uono, Shota; Yoshikawa, Sakiko

    2008-01-01

    The human superior temporal sulcus (STS) has been suggested to be involved in gaze processing, but temporal data regarding this issue are lacking. We investigated this topic by combining fMRI and MEG in four normal subjects. Photographs of faces with either averted or straight eye gazes were presented and subjects passively viewed the stimuli. First, we analyzed the brain areas involved using fMRI. A group analysis revealed activation of the STS for averted compared to straight gazes, which was confirmed in all subjects. We then measured brain activity using MEG, and conducted a 3D spatial filter analysis. The STS showed higher activity in response to averted versus straight gazes during the 150–200 ms period, peaking at around 170 ms, after stimulus onset. In contrast, the fusiform gyrus, which was detected by the main effect of stimulus presentations in fMRI analysis, exhibited comparable activity across straight and averted gazes at about 170 ms. These results indicate involvement of the human STS in rapid processing of the eye gaze of another individual. PMID:19015114

  4. Cortical fMRI activation produced by attentive tracking of moving targets.

    Science.gov (United States)

    Culham, J C; Brandt, S A; Cavanagh, P; Kanwisher, N G; Dale, A M; Tootell, R B

    1998-11-01

    Attention can be used to keep track of moving items, particularly when there are multiple targets of interest that cannot all be followed with eye movements. Functional magnetic resonance imaging (fMRI) was used to investigate cortical regions involved in attentive tracking. Cortical flattening techniques facilitated within-subject comparisons of activation produced by attentive tracking, visual motion, discrete attention shifts, and eye movements. In the main task, subjects viewed a display of nine green "bouncing balls" and used attention to mentally track a subset of them while fixating. At the start of each attentive-tracking condition, several target balls (e.g., 3/9) turned red for 2 s and then reverted to green. Subjects then used attention to keep track of the previously indicated targets, which were otherwise indistinguishable from the nontargets. Attentive-tracking conditions alternated with passive viewing of the same display when no targets had been indicated. Subjects were pretested with an eye-movement monitor to ensure they could perform the task accurately while fixating. For seven subjects, functional activation was superimposed on each individual's cortically unfolded surface. Comparisons between attentive tracking and passive viewing revealed bilateral activation in parietal cortex (intraparietal sulcus, postcentral sulcus, superior parietal lobule, and precuneus), frontal cortex (frontal eye fields and precentral sulcus), and the MT complex (including motion-selective areas MT and MST). Attentional enhancement was absent in early visual areas and weak in the MT complex. However, in parietal and frontal areas, the signal change produced by the moving stimuli was more than doubled when items were tracked attentively. Comparisons between attentive tracking and attention shifting revealed essentially identical activation patterns that differed only in the magnitude of activation. This suggests that parietal cortex is involved not only in discrete

  5. UV-activated 7-dehydrocholesterol-coated titanium implants promote differentiation of human umbilical cord mesenchymal stem cells into osteoblasts.

    Science.gov (United States)

    Satué, María; Ramis, Joana M; Monjo, Marta

    2016-01-01

    Vitamin D metabolites are essential for bone regeneration and mineral homeostasis. The vitamin D precursor 7-dehydrocholesterol can be used after UV irradiation to locally produce active vitamin D by osteoblastic cells. Furthermore, UV-irradiated 7-dehydrocholesterol is a biocompatible coating for titanium implants with positive effects on osteoblast differentiation. In this study, we examined the impact of titanium implants surfaces coated with UV-irradiated 7-dehydrocholesterol on the osteogenic differentiation of human umbilical cord mesenchymal stem cells. First, the synthesis of cholecalciferol (D3) was achieved through the incubation of the UV-activated 7-dehydrocholesterol coating for 48 h at 23℃. Further, we investigated in vitro the biocompatibility of this coating in human umbilical cord mesenchymal stem cells and its potential to enhance their differentiation towards the osteogenic lineage. Human umbilical cord mesenchymal stem cells cultured onto UV-irradiated 7-dehydrocholesterol-coated titanium implants surfaces, combined with osteogenic supplements, upregulated the gene expression of several osteogenic markers and showed higher alkaline phosphatase activity and calcein blue staining, suggesting increased mineralization. Thus, our results show that the use of UV irradiation on 7-dehydrocholesterol -treated titanium implants surfaces generates a bioactive coating that promotes the osteogenic differentiation of human umbilical cord mesenchymal stem cells, with regenerative potential for improving osseointegration in titanium-based bone anchored implants.

  6. Defining active sacroiliitis on magnetic resonance imaging (MRI) for classification of axial spondyloarthritis: a consensual approach by the ASAS/OMERACT MRI group

    DEFF Research Database (Denmark)

    Rudwaleit, M; Jurik, A G; Hermann, K-G A

    2009-01-01

    be detected by MRI. At present, however, the exact place of structural damage lesions for diagnosis and classification is less clear, particularly if these findings are minor. The ASAS group formally approved these proposals by voting at the annual assembly. CONCLUSIONS: For the first time, MRI findings...

  7. Neural Response during the Activation of the Attachment System in Patients with Borderline Personality Disorder: An fMRI Study

    OpenAIRE

    Buchheim, Anna; Erk, Susanne; George, Carol; Kächele, Horst; Martius, Philipp; Pokorny, Dan; Spitzer, Manfred; Walter, Henrik

    2016-01-01

    Individuals with borderline personality disorder (BPD) are characterized by emotional instability, impaired emotion regulation and unresolved attachment patterns associated with abusive childhood experiences. We investigated the neural response during the activation of the attachment system in BPD patients compared to healthy controls using functional magnetic resonance imaging (fMRI). Eleven female patients with BPD without posttraumatic stress disorder (PTSD) and 17 healthy female controls ...

  8. MRI and low back pain

    Science.gov (United States)

    Backache - MRI; Low back pain - MRI; Lumbar pain - MRI; Back strain - MRI; Lumbar radiculopathy - MRI; Herniated intervertebral disk - MRI; Prolapsed intervertebral disk - MRI; Slipped disk - MRI; Ruptured ...

  9. Pomegranate Juice Augments Memory and fMRI Activity in Middle-Aged and Older Adults with Mild Memory Complaints

    Directory of Open Access Journals (Sweden)

    Susan Y. Bookheimer

    2013-01-01

    Full Text Available Despite increasing emphasis on the potential of dietary antioxidants in preventing memory loss and on diet as a precursor of neurological health, rigorous studies investigating the cognitive effects of foods and their components are rare. Recent animal studies have reported memory and other cognitive benefits of polyphenols, found abundantly in pomegranate juice. We performed a preliminary, placebo-controlled randomized trial of pomegranate juice in older subjects with age-associated memory complaints using memory testing and functional brain activation (fMRI as outcome measures. Thirty-two subjects (28 completers were randomly assigned to drink 8 ounces of either pomegranate juice or a flavor-matched placebo drink for 4 weeks. Subjects received memory testing, fMRI scans during cognitive tasks, and blood draws for peripheral biomarkers before and after the intervention. Investigators and subjects were all blind to group membership. After 4 weeks, only the pomegranate group showed a significant improvement in the Buschke selective reminding test of verbal memory and a significant increase in plasma trolox-equivalent antioxidant capacity (TEAC and urolithin A-glucuronide. Furthermore, compared to the placebo group, the pomegranate group had increased fMRI activity during verbal and visual memory tasks. While preliminary, these results suggest a role for pomegranate juice in augmenting memory function through task-related increases in functional brain activity.

  10. Enhanced Sympathetic Arousal in Response to fMRI Scanning Correlates with Task Induced Activations and Deactivations

    Science.gov (United States)

    Muehlhan, Markus; Lueken, Ulrike; Siegert, Jens; Wittchen, Hans-Ulrich; Smolka, Michael N.; Kirschbaum, Clemens

    2013-01-01

    It has been repeatedly shown that functional magnetic resonance imaging (fMRI) triggers distress and neuroendocrine response systems. Prior studies have revealed that sympathetic arousal increases, particularly at the beginning of the examination. Against this background it appears likely that those stress reactions during the scanning procedure may influence task performance and neural correlates. However, the question how sympathetic arousal elicited by the scanning procedure itself may act as a potential confounder of fMRI data remains unresolved today. Thirty-seven scanner naive healthy subjects performed a simple cued target detection task. Levels of salivary alpha amylase (sAA), as a biomarker for sympathetic activity, were assessed in samples obtained at several time points during the lab visit. SAA increased two times, immediately prior to scanning and at the end of the scanning procedure. Neural activation related to motor preparation and timing as well as task performance was positively correlated with the first increase. Furthermore, the first sAA increase was associated with task induced deactivation (TID) in frontal and parietal regions. However, these effects were restricted to the first part of the experiment. Consequently, this bias of scanner related sympathetic activation should be considered in future fMRI investigations. It is of particular importance for pharmacological investigations studying adrenergic agents and the comparison of groups with different stress vulnerabilities like patients and controls or adolescents and adults. PMID:23967320

  11. Lateral visual field stimulation reveals extrastriate cortical activation in the contralateral hemisphere: an fMRI study.

    Science.gov (United States)

    Schiffer, Fredric; Mottaghy, Felix M; Pandey Vimal, Ram Lakhan; Renshaw, Perry F; Cowan, Ronald; Pascual-Leone, Alvaro; Teicher, Martin; Valente, Elizabeth; Rohan, Michael

    2004-05-30

    We examined whether lateral visual field stimulation (LSTM) could activate contralateral extrastriate cortical areas as predicted by a large experimental literature. We asked seven unscreened, control subjects to wear glasses designed to allow vision out of either the left (LVF) or right lateral visual field (RVF) depending upon which side the subject looked toward. Each subject participated in a block design functional magnetic resonance imaging (fMRI) study with alternating 30-s epochs in which he was asked to look to one side and then the other for a total of five epochs. On each side of the bore of the scanner, we taped a photograph for the subject to view in the LVF and RVF. The data were analyzed with SPM99 using a fixed effect, box-car design with contrasts for the LVF and the RVF conditions. Both LVF and RVF conditions produced the strongest fMRI activation in the contralateral occipitotemporal and posterior parietal areas as well as the contralateral dorsolateral prefrontal cortex. LSTM appears to increase contralateral fMRI activation in striate and extrastriate cortical areas as predicted by earlier studies reporting differential cognitive and/or emotional effects from unilateral sensory or motor stimulation.

  12. Tracing Activity across the Whole Brain Neural Network with Optogenetic Functional Magnetic Resonance Imaging (ofMRI

    Directory of Open Access Journals (Sweden)

    Jin Hyung eLee

    2011-10-01

    Full Text Available Despite the overwhelming need, there has been a relatively large gap in our ability to trace network level activity across the brain. The complex dense wiring of the brain makes it extremely challenging to understand a specific set of neuron’s activity and their communication beyond a few synapses. Recent development of the optogenetic functional magnetic resonance imaging (ofMRI provides a new impetus for the study of the brain circuit by enabling causal tracing of the brain circuit activity across the whole brain. Brain circuit elements can be selectively triggered based on their genetic identity, cell body location, and/or their axonal projection target with temporal precision while the resulting network response is monitored non-invasively with unprecedented spatial and temporal accuracy. With further studies including technological innovations to bring ofMRI to its full potential, ofMRI is expected to play an important role in our system-level understanding of the brain circuit mechanism.

  13. Correlation between amygdala BOLD activity and frontal EEG asymmetry during real-time fMRI neurofeedback training in patients with depression

    CERN Document Server

    Zotev, Vadim; Misaki, Masaya; Phillips, Raquel; Young, Kymberly D; Feldner, Matthew T; Bodurka, Jerzy

    2014-01-01

    Background: Real-time fMRI neurofeedback (rtfMRI-nf) is a promising approach for studies and treatment of major depressive disorder (MDD). EEG performed simultaneously with rtfMRI-nf procedure allows independent evaluation of rtfMRI-nf effects. Frontal EEG asymmetry in the alpha band is a widely used measure of emotion and motivation that shows profound changes in depression. However, it has never been related to simultaneously acquired fMRI data. Methods: We performed the first study combining rtfMRI-nf with simultaneous (passive) EEG recordings. MDD patients in the experimental group (n=13) learned to upregulate BOLD activity of the left amygdala using rtfMRI-nf during a positive emotion induction task. MDD patients in the control group (n=11) were provided with sham rtfMRI-nf. Correlations between frontal EEG asymmetry in the upper-alpha band and BOLD activity across the brain were examined. Results: Participants in the experimental group showed positive average changes in frontal EEG asymmetry during the ...

  14. Interference of cardiac pacemaker and implantable cardioverter-defibrillator activity during electronic dental device use.

    Science.gov (United States)

    Roedig, Jason J; Shah, Jignesh; Elayi, Claude Samy; Miller, Craig S

    2010-05-01

    The authors conducted a study to determine if electromagnetic interference of cardiac pacemaker and implantable cardioverter-defibrillator (ICD) activity occurs during the operation of electronic dental devices. The authors tested nine electronic dental devices in vitro to assess their ability to interfere with the function of two pacemakers and two ICDs as determined by electrocardiographic telemetry. The pacing activity of both pacemakers and the dual-chamber ICD were inhibited during operation of the battery-operated composite curing light at between 2 and 10 centimeters from the generator or leads. The use of the ultrasonic scaler interfered with the pacing activity of the dual-chamber pacemaker at between 17 and 23 cm from the generator or leads, the single-chamber pacemaker at 15 cm from the generator or leads and both ICDs at 7 cm from the leads. The operation of the ultrasonic cleaning system interfered with the activity of the dual-chamber pacemaker at between 15 and 23 cm from the generator or leads, and of the single-chamber pacemaker at 12 cm. Operation of the electric toothbrush, electrosurgical unit, electric pulp tester, high- and low-speed handpieces, and an amalgamator did not alter pacing function. Select electronic dental devices interfere with pacemakers' and ICDs' sensing and pacing activity in vitro. Use of the ultrasonic scaler, ultrasonic cleaning system and battery-operated composite curing light may produce deleterious effects in patients who have pacemakers or ICDs.

  15. Surface coatings for improvement of bone cell materials and antimicrobial activities of Ti implants.

    Science.gov (United States)

    Das, Kakoli; Bose, Susmita; Bandyopadhyay, Amit; Karandikar, Balu; Gibbins, Bruce L

    2008-11-01

    Ti surface was modified to simultaneously improve bone cell materials and antimicrobial activities. Titanium surface was first anodized in sodium fluoride and sulfuric acid electrolytic solution to form titania nanotube on the surface to improve the biocompatibility of the surface. Silver was electrodeposited on the titania nanotube surface at 5 V. Silver added titania nanotube surface was tested for compatibility with bone-cell materials interactions using human osteoblast bone cells. The antibacterial effect was studied using Pseudomonas aeruginosa. Our results show that silver-treated titania nanotube surface may provide antibacterial properties to prevent implants against postoperative infections without interference to the attachment and proliferation of bone tissue on titanium, which is commonly used in dental and orthopedic surgical procedures.

  16. The "edge effect" after implantation of beta-emitting (55Co) stents with high initial activity.

    Science.gov (United States)

    Cervinka, Pavel; St'ásek, Josef; Costa, Marco Aurelio; Stursa, Jan; Fiser, Miloslav; Vodnanský, Petr; Kocisová, Michaela; Veselka, Josef; Pleskot, Miloslav; Malý, Jaroslav

    2004-01-01

    The aim of this study was to evaluate the incidence and the cause of "edge restenosis" after implantation of high activity 41.1 microCi +/- 1.2 microCi = 1520 kBq +/- 44 kBq, beta-emitting (55Co) stents. Proton bombarding in cyclotron has brought the radioactivity. Intravascular ultrasound (IVUS) investigation has been completed in 10 patients. The angiographies performed at 6 month revealed restenosis >50% in 5 cases (50%). The analysis of edges (5 mm distally and proximally to the last stent struts) showed no significant changes in TVV (187.3 +/- 62.60 mm3 and 176.9 +/- 53.5 mm3) but PMV increase significantly (i.e. neointimal proliferation) from 61.9 +/- 31.2 mm3 to 82.2 +/- 43.4 mm3 (pedge effect"/neointimal hyperplasia was in this trial sharp fall-off in radiation at the edges of the stents.

  17. Protection of active implant electronics with organosilicon open air plasma coating for plastic overmolding

    Directory of Open Access Journals (Sweden)

    Zeppenfeld Matthias

    2016-09-01

    Full Text Available To overcome challenges for manufacturing of modern smart medical plastic parts by injection molding, e.g. for active implants, the optimization of the interface between electronics and the polymer component concerning adhesion and diffusion behavior is crucial. Our results indicate that a nano-sized SiOxCyHz layer formed by plasma-enhanced chemical vapour deposition (PE-CVD via open air atmospheric pressure plasma jet (APPJ and by use of a hexamthyldisiloxane (HMDSO precursor can form a non-corrosive, anti-permeable and biocompatible coating. Due to the open air character of the APPJ process an inline coating before overmolding could be an easy applicable method and a promising advancement.

  18. COUP-TFII mediates progesterone regulation of uterine implantation by controlling ER activity.

    Directory of Open Access Journals (Sweden)

    Isao Kurihara

    2007-06-01

    Full Text Available Progesterone and estrogen are critical regulators of uterine receptivity. To facilitate uterine remodeling for embryo attachment, estrogen activity in the uterine epithelia is attenuated by progesterone; however, the molecular mechanism by which this occurs is poorly defined. COUP-TFII (chicken ovalbumin upstream promoter transcription factor II; also known as NR2F2, a member of the nuclear receptor superfamily, is highly expressed in the uterine stroma and its expression is regulated by the progesterone-Indian hedgehog-Patched signaling axis that emanates from the epithelium. To further assess COUP-TFII uterine function, a conditional COUP-TFII knockout mouse was generated. This mutant mouse is infertile due to implantation failure, in which both embryo attachment and uterine decidualization are impaired. Using this animal model, we have identified a novel genetic pathway in which BMP2 lies downstream of COUP-TFII. Epithelial progesterone-induced Indian hedgehog regulates stromal COUP-TFII, which in turn controls BMP2 to allow decidualization to manifest in vivo. Interestingly, enhanced epithelial estrogen activity, which impedes maturation of the receptive uterus, was clearly observed in the absence of stromal-derived COUP-TFII. This finding is consistent with the notion that progesterone exerts its control of implantation through uterine epithelial-stromal cross-talk and reveals that stromal-derived COUP-TFII is an essential mediator of this complex cross-communication pathway. This finding also provides a new signaling paradigm for steroid hormone regulation in female reproductive biology, with attendant implications for furthering our understanding of the molecular mechanisms that underlie dysregulation of hormonal signaling in such human reproductive disorders as endometriosis and endometrial cancer.

  19. CDIC纯钛种植体与金属烤瓷冠修复体在磁共振成像检查中的伪影影响%The Influence of CDIC Dental Implant and Baked Porcelain Metal Crown on Diagnosis of Coronal by MRI

    Institute of Scientific and Technical Information of China (English)

    董军; 刘宏

    2001-01-01

    目的:观察在颅脑磁共振成像(MR)检查中,口腔内种植体和烤瓷金属冠对MRI影像学诊断的影响。方法:观察在颅脑MRI检查中,CDIC种植体与金属烤瓷修复体的伪影变化。结果:种植体伪影最小,烤瓷钢伪影仅为铸造钢合金的三分之一左右。结论:CDIC种植体和口腔内特定位置的烤瓷金属修复体不影响头颅MRI诊断。%To investigate the influence of CDIC dental implant and baked porcelain metal crown on MRI image. Method: The pseudomorphs of two kinds of metal implants were observed during coronal MRI. Results:CDIC dental implantd produces little influence on coronal MRI and the baked porcelain metal crown makes only one thirds of less pseudomorphs than that made by fasting steel. Conclusions: There are no negative effects on diagnosis of coronal MRI with regard to CDIC dental implants and baked porcelain metal crown.

  20. Anti-infection activity of nanostructured titanium percutaneous implants with a postoperative infection model

    Science.gov (United States)

    Tan, Jing; Li, Yiting; Liu, Zhiyuan; Qu, Shuxin; Lu, Xiong; Wang, Jianxin; Duan, Ke; Weng, Jie; Feng, Bo

    2015-07-01

    The titanium percutaneous implants were widely used in clinic; however, they have an increased risk of infection since they breach the skin barrier. Lack of complete skin integration with the implants can cause infection and implant removal. In this work, three titania nanotubes (TNT) with different diameters, 50 nm (TNT-50), 100 nm (TNT-100) and 150 nm (TNT-150) arrays were prepared on titanium surfaces by anodization, pure titanium (pTi) was used as control. Samples were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), and contact angle analysis. The antibacterial efficiency of TNT was evaluated in vitro against Staphylococcus aureus under the visible light. The results indicated that TNT-100 had the highest antibacterial efficiency under the visible light. Subsequently, TNT implants and pTi implants were placed subcutaneously to the dorsum of New Zealand White rabbits, 108 CFU S. aureus was inoculated into the implant sites 4 h after surgery. The TNF-alpha and IL-1alpha were determined using enzyme linked immunoassay (ELISA). TNT implants revealed less inflammatory factor release than pTi implants with or without injected S. aureus liquid. According to the histological results, the TNT implants displayed excellent tissue integration. Whereas, pTi implants were surrounded with fibrotic capsule, and the skin tissue was almost separated from the implant surface. Therefore, the TNT significantly inhibited the infection risk and enhanced tissue integration of the percutaneous implants compared to pTi. The immersion test in the culture medium suggested that one of causes be probably more proteins adsorbed on TNT than on pTi.

  1. Magnetic Resonance, Functional (fMRI) -- Brain

    Science.gov (United States)

    ... their nature and the strength of the MRI magnet. Many implanted devices will have a pamphlet explaining ... large cylinder-shaped tube surrounded by a circular magnet. You will lie on a moveable examination table ...

  2. Active middle ear implantation for patients with sensorineural hearing loss and external otitis: long-term outcome in patient satisfaction

    NARCIS (Netherlands)

    Zwartenkot, J.W.; Hashemi, J.; Cremers, C.W.R.J.; Mulder, J.J.S.; Snik, A.F.M.

    2013-01-01

    OBJECTIVE: To study long-term subjective benefit of patients with sensorineural hearing loss and chronic external otitis who use active middle ear implants. DESIGN: Single-subject repeated measures in a preintervention and postintervention design with multiple postintervention measurements (question

  3. A randomized controlled trial of an implantable 2-channel peroneal nerve stimulator on walking speed and activity in poststroke hemiplegia

    NARCIS (Netherlands)

    Kottink, A.I.R.; Kottink, Anke I.; Hermens, Hermanus J.; Nene, A.V.; Tenniglo, Martinus Johannes Bernardus; van der Aa, Hans E.; Buschman, H.P.J.; IJzerman, Maarten Joost

    Objective To determine the effect of a new implantable 2-channel peroneal nerve stimulator on walking speed and daily activities, in comparison with the usual treatment in chronic stroke survivors with a drop foot. Design Randomized controlled trial. Setting All subjects were measured 5 times in the

  4. A computer-aided detection system for rheumatoid arthritis MRI data interpretation and quantification of synovial activity

    Energy Technology Data Exchange (ETDEWEB)

    Kubassova, Olga, E-mail: olga@imageanalysis.org.u [Image Analysis Ltd., The Waterfront, Old Mill Lane, Saltaire BD17 7EZ (United Kingdom); Boesen, Mikael, E-mail: parker@frh.regionh.d [Parker Institute, Frederiksberg Hospital, Nordre Fasanvej 57, 2000 Frederiksberg, Copenhagen (Denmark); Cimmino, Marco A., E-mail: cimmino@unige.i [Clinica Reumatologica, DI.M.I., Universita di Genova, Viale Benedetto XV, 6, 16129 Genova (Italy); Bliddal, Henning [Parker Institute, Frederiksberg Hospital, Nordre Fasanvej 57, 2000 Frederiksberg, Copenhagen (Denmark)

    2010-06-15

    Rational and objective: Disease assessment and follow-up of rheumatoid arthritis (RA) patients require objective evaluation and quantification. Magnetic resonance imaging (MRI) has a large potential to supplement such information for the clinician, however, time spent on data reading and interpretation slow down development in this area. Existing scoring systems of especially synovitis are too rigid and insensitive to measure early treatment response and quantify inflammation. This study tested a novel automated, computer system for analysis of dynamic MRI data acquired from patients with RA, Dynamika-RA, which incorporates efficient data processing and analysis techniques. Materials and methods: 140 MRI scans from hands and wrists of 135 active RA patients and 5 healthy controls were processed using Dynamika-RA and evaluated with RAMRIS. To reduce patient motion artefacts, MRI data were processed using Dynamika-RA, which removed motion in 2D and 3D planes. Then synovial enhancement was visualised and qualified using a novel fully automated voxel-by-voxel analysis based algorithm. This algorithm was used to replace traditional region-of-interest (ROI) and subtraction methods, yielding observer independent quantitative results. Results: Conventional scoring performed by an observer took 30-45 min per dataset. Dynamika-RA reduced motion artefacts, visualised inflammation and quantified disease activity in less than 3 min. Data processing allowed increasing signal to noise ratio by a factor 3. Due to fully automated procedure of data processing, there was no intertest variation in the results. Conclusions: Algorithms incorporated into Dynamika-RA allow for the significant enhancement of data quality through eliminating motion artefacts and reduction of time for evaluation of synovial inflammation.

  5. Implantable Heart Aid

    Science.gov (United States)

    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.

  6. 3D perfusion bioreactor-activated porous granules on implant fixation and early bone formation in sheep

    DEFF Research Database (Denmark)

    Ding, Ming; Snoek Henriksen, Susan; Martinetti, Roberta

    2017-01-01

    Early fixation of total joint arthroplasties is crucial for ensuring implant survival. An alternative bone graft material in revision surgery is needed to replace the current gold standard, allograft, seeing that the latter is associated with several disadvantages. The incubation of such a constr......, bone formation was observed in all groups, while the bioreactor-activated graft material did not reveal additional effects on early implant fixation comparable to allograft in this model. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2016....

  7. Down-regulation of amygdala activation with real-time fMRI neurofeedback in a healthy female sample

    Directory of Open Access Journals (Sweden)

    Christian eParet

    2014-09-01

    Full Text Available Psychiatric conditions of emotion dysregulation are often characterized by difficulties in regulating the activity of limbic regions such as the amygdala. Real-time functional magnetic resonance imaging (rt-fMRI allows to feedback brain activation and opens the possibility to establish a neurofeedback (NF training of amygdala activation, e.g. for subjects suffering from emotion dysregulation.As a first step, we investigated whether feedback of the amygdala response to aversive scenes can improve down-regulation of amygdala activation. One group of healthy female participants received amygdala feedback (N=16 and a control group was presented with feedback from a control region located in the basal ganglia (N(sum=32. Subjects completed a one-session rt-fMRI-NF training where they viewed aversive pictures and received continuous visual feedback on brain activation (REGULATE condition. In a control condition, subjects were advised to respond naturally to aversive pictures (VIEW, and a neutral condition served as the non-affective control (NEUTRAL. In an adjacent run, subjects were presented with aversive pictures without feedback to test for transfer effects of learning.In a region of interest (ROI analysis, the VIEW and the REGULATE conditions were contrasted to estimate brain regulation success. The ROI analysis was complemented by an exploratory analysis of activations at the whole brain level. Both groups showed down-regulation of the amygdala response during training. Feedback from the amygdala but not from the control region was associated with down-regulation of the right amygdala in the transfer test. The whole-brain analysis did not detect significant group interactions. Results of the group whole-brain analyses are discussed.We present a proof-of-concept study using rt-fMRI-NF for amygdala down-regulation in the presence of aversive scenes. Results are in line with a potential benefit of neurofeedback training for amygdala regulation.

  8. Magnetic resonance imaging of trilucent TM breast implants

    Energy Technology Data Exchange (ETDEWEB)

    Elson, Elspeth M.; Jones, Annette; King, Rebecca; Chapman, P.; Stanek, Jan; Irvine, Allan T.; Bingham, John B

    2002-04-01

    AIM: To demonstrate the magnetic resonance imaging (MRI) appearances of intact and ruptured Trilucent TM implants with imaging and surgical correlation. The appearances of the implant transponder artefact are also described MATERIALS AND METHODS: A retrospective review of the MRI findings in 34 patients with bilateral subpectoral Trilucent TM breast implants (Lipomatrix, Inc./Collagen Aesthetics International Inc., Neuchatel, Switzerland) was performed. Patients under implant surveillance and those with suspected implant rupture formed the study group. Imaging findings were correlated with surgical appearances. RESULTS: Surgical correlation was available in 53% of patients. Fifty per cent (18/36) of implants were intact at surgery, 50% (18/36) of implants were ruptured. Of the 18 ruptured implants, 17 were intracapsular ruptures and one an extracapsular rupture. The sensitivity of MRI for detection of intracapsular rupture in Trilucent TM breast implants was 82% specificity 76%, positive predictive value 78%, negative predictive value 81% and accuracy 79% in this study group. No case of implant rupture was obscured by the transponder artefact. Four implants were found to have 'pseudocapsules' at surgery (5{center_dot}9%), the implants were intact with fluid present between the implant and capsule. Only one pseudocapsule was demonstrated on MRI. CONCLUSION: Magnetic resonance imaging is currently the most accurate technique for diagnosis of implant rupture in Trilucent TM breast implants. Transponder artefact does not appear to interfere with the assessment of implant rupture. Elson, E. M. et al. (2002)

  9. [The active middle ear implant for the rehabilitation of sensorineural, mixed and conductive hearing losses].

    Science.gov (United States)

    Sprinzl, G M; Wolf-Magele, A; Schnabl, J; Koci, V

    2011-09-01

    Active middle ear implants, such as the Vibrant Soundbridge, are used as an important part in the rehabilitation of sensorineural, conductive hearing, or mixed hearing loss. The attachment of the Vibrant Soundbridge at the round window and the usage of the Vibroplasty couplers strongly expanded the application of the Vibrant Soundbridge.The Vibrant Soundbridge is developed for patients who have an intolerance to hearing aids and a moderate to profound sensorineural hearing loss. The VSB also provides an optimal solution for patients with failed middle ear reconstructions or patients with atresia. To capture the improvement with the VSB Implant with different hearing losses a literature analysis was conducted. The functional gain was analyzed for 107 patients with conductive hearing loss and for 214 patients with sensorineural hearing loss out of 14 studies.Patients with conductive and mixed hearing loss resulted in a functional gain from 30 to 58 dB with the VSB. Patients with a pure sensorineural hearing loss showed a functional gain of 23-30 dB. The VSB bone conduction threshold shift was analyzed for all studies conducted in the years between 2000 and 2009. In 11 of the 16 studies there was no significant (p=0.05) change found. In 5 studies, the pre- to post-surgical bone conduction threshold shift was less than 10 dB. None of these studies measured a threshold shift of more than 10 dB.The flexible attachment at either the long process of the incus with sensorineural hearing loss, with an conductive hearing loss at the round window or the use of Vibroplasty couplers at the oval window, head of the stapes or round window makes the VSB an extremely versatile instrument. If patients can't wear conventional hearing aids, had failed middle ear reconstructions or atresia the VSB presents, due to the significant hearing improvement in any type of hearing loss, an ideal solution.

  10. Frontopolar and anterior temporal cortex activation in a moral judgment task. Preliminary functional MRI results in normal subjects

    Energy Technology Data Exchange (ETDEWEB)

    Moll, Jorge [LABS and Rede D' Or Hospitais, Rio de Janeiro RJ (Brazil). Grupo de Neuroimagem e Neurologia do Comportamento; Eslinger, Paul J. [Pensylvania State Univ. (United States). College of Medicine. Div. of Neurology and Behavioral Science; The Milton S. Hershey Medical Center, Hershey, PN (United States); Oliveira-Souza, Ricardo de [Universidade do Rio de Janeiro (UNI-Rio), RJ (Brazil). Hospital Universitario Gaffree e Guinle]. E-mail: neuropsychiatry@hotmail.com

    2001-09-01

    The objective was to study the brain areas which are activated when normal subjects make moral judgments. Ten normal adults underwent BOLD functional magnetic resonance imaging (fMRI) during the auditory presentation of sentences that they were instructed to silently judge as either 'right' or 'wrong'. Half of the sentences had an explicit moral content ('We break the law when necessary'), the other half comprised factual statements devoid of moral connotation ('Stones are made of water'). After scanning, each subject rated the moral content, emotional valence, and judgment difficulty of each sentence on Likert-like scales. To exclude the effect of emotion on the activation results, individual responses were hemo dynamically modeled for event-related f MRI analysis. The general linear model was used to evaluate the brain areas activated by moral judgment. Regions activated during moral judgment included the frontopolar cortex (FPC), medial frontal gyrus, right anterior temporal cortex, lenticular nucleus, and cerebellum. Activation of FPC and medial frontal gyrus (B A 10/46 and 9) were largely independent of emotional experience and represented the largest areas of activation. These results concur with clinical observations assigning a critical role for the frontal poles and right anterior temporal cortex in the mediation of complex judgment processes according to moral constraints. The FPC may work in concert with the orbitofrontal and dorsolateral cortex in the regulation of human social conduct. (author)

  11. MRI after implantation of a novel femoral closure device following intra-arterial catheterisation: implications for subsequent contrast-enhanced MR angiography.

    Science.gov (United States)

    Mohrs, Oliver K; Petersen, Steffen E; Nowak, Bernd; Kauczor, Hans-Ulrich; Voigtlaender, Thomas

    2010-05-01

    To assess MRI safety aspects and artefacts of a novel femoral artery closure device during contrast-enhanced MR angiography in patients following intra-arterial catheterisation. Ten consecutive patients underwent MRI within 24 h of coronary angiography and placement of a femoral artery closure device. We used a T2-weighted gradient-echo MRI sequence to measure the device-related artefact size in comparison with a phantom image, phase-contrast flow measurement proximal to, at the level of and distal to the device to quantify potential differences in flow velocity and contrast-enhanced 3D gradient-echo MR angiography to differentiate potential femoral artery stenosis from device-related artefacts. The mean size of the oval-shaped artefact was 8.4 x 6.6 mm (+/-1.0 x 0.8 mm) and was almost identical to the maximum artefact size of the phantom measurement (8.3 x 5.7 mm). Device placement did not result in an increased peak velocity (proximal 69 +/- 23 cm/s, at the level of 64 +/- 11 cm/s and distal to the device 63 +/- 12 cm/s, p = 0.67). The mean artefact penetration into the vessel lumen was 0.5 +/- 0.5 mm (percentage vessel narrowing 7.0 +/- 6%; range 0-16%). The MR conditional StarClose femoral artery closure device was used safely within 24 h of deployment at 1.5 T. Despite clip-related artefacts MR angiography will allow for easy differentiation of clip-related artefacts from high-grade atherosclerotic stenosis.

  12. MRI after implantation of a novel femoral closure device following intra-arterial catheterisation: implications for subsequent contrast-enhanced MR angiography

    Energy Technology Data Exchange (ETDEWEB)

    Mohrs, Oliver K. [University of Heidelberg, Department of Diagnostic and Interventional Radiology, Heidelberg (Germany); Darmstadt Radiology, Department of Cardiovascular Imaging at Alice-Hospital, Darmstadt (Germany); Petersen, Steffen E. [The London Chest Hospital, William Harvey Research Institute, Centre Lead for Advanced Cardiovascular Imaging, London (United Kingdom); Nowak, Bernd; Voigtlaender, Thomas [Cardiovascular Center Bethanien (CCB), Frankfurt/Main (Germany); Kauczor, Hans-Ulrich [University of Heidelberg, Department of Diagnostic and Interventional Radiology, Heidelberg (Germany)

    2010-05-15

    To assess MRI safety aspects and artefacts of a novel femoral artery closure device during contrast-enhanced MR angiography in patients following intra-arterial catheterisation. Ten consecutive patients underwent MRI within 24 h of coronary angiography and placement of a femoral artery closure device. We used a T2-weighted gradient-echo MRI sequence to measure the device-related artefact size in comparison with a phantom image, phase-contrast flow measurement proximal to, at the level of and distal to the device to quantify potential differences in flow velocity and contrast-enhanced 3D gradient-echo MR angiography to differentiate potential femoral artery stenosis from device-related artefacts. The mean size of the oval-shaped artefact was 8.4 x 6.6 mm ({+-}1.0 x 0.8 mm) and was almost identical to the maximum artefact size of the phantom measurement (8.3 x 5.7 mm). Device placement did not result in an increased peak velocity (proximal 69 {+-} 23 cm/s, at the level of 64 {+-} 11 cm/s and distal to the device 63 {+-} 12 cm/s, p = 0.67). The mean artefact penetration into the vessel lumen was 0.5 {+-} 0.5 mm (percentage vessel narrowing 7.0 {+-} 6%; range 0-16%). The MR conditional StarClose femoral artery closure device was used safely within 24 h of deployment at 1.5 T. Despite clip-related artefacts MR angiography will allow for easy differentiation of clip-related artefacts from high-grade atherosclerotic stenosis. (orig.)

  13. Penile Implants

    Science.gov (United States)

    ... the discussion with your doctor. Types of penile implants There are two main types of penile implants: ... might help reduce the risk of infection. Comparing implant types When choosing which type of penile implant ...

  14. The diagnosis of breast implant rupture

    DEFF Research Database (Denmark)

    Hölmich, Lisbet R; Vejborg, Ilse; Conrad, Carsten;

    2005-01-01

    STUDY OBJECTIVE: The aim of this study was to evaluate the accuracy of Magnetic Resonance Imaging (MRI) as performed according to a strict study protocol in diagnosing rupture of silicone breast implants. MATERIAL AND METHODS: The study population consisted of 64 women with 118 implants, who had...... participated in either one or two study MRI examinations, aiming at determining the prevalence and incidence of silent implant rupture, respectively, and who subsequently underwent explantation. Implant rupture status was determined by four independent readers and a consensus diagnosis of either rupture...... (intracapsular or extracapsular), possible rupture or intact implant was then obtained. Strict predetermined rupture criteria were applied as described in this report and findings at surgery were abstracted in a standardised manner and results compared. RESULTS: At MRI, 66 implants were diagnosed as ruptured...

  15. Does breast MRI background parenchymal enhancement indicate metabolic activity? Qualitative and 3D quantitative computer imaging analysis.

    Science.gov (United States)

    Mema, Eralda; Mango, Victoria L; Guo, Xiaotao; Karcich, Jenika; Yeh, Randy; Wynn, Ralph T; Zhao, Binsheng; Ha, Richard S

    2017-06-24

    To investigate whether the degree of breast magnetic resonance imaging (MRI) background parenchymal enhancement (BPE) is associated with the amount of breast metabolic activity measured by breast parenchymal uptake (BPU) of 18F-FDG on positron emission tomography / computed tomography (PET/CT). An Institutional Review Board (IRB)-approved retrospective study was performed. Of 327 patients who underwent preoperative breast MRI from 1/1/12 to 12/31/15, 73 patients had 18F-FDG PET/CT evaluation performed within 1 week of breast MRI and no suspicious findings in the contralateral breast. MRI was performed on a 1.5T or 3.0T system. The imaging sequence included a triplane localizing sequence followed by sagittal fat-suppressed T2 -weighted sequence, and a bilateral sagittal T1 -weighted fat-suppressed fast spoiled gradient-echo sequence, which was performed before and three times after a rapid bolus injection (gadobenate dimeglumine, Multihance; Bracco Imaging; 0.1 mmol/kg) delivered through an IV catheter. The unaffected contralateral breast in these 73 patients underwent BPE and BPU assessments. For PET/CT BPU calculation, a 3D region of interest (ROI) was drawn around the glandular breast tissue and the maximum standardized uptake value (SUVmax ) was determined. Qualitative MRI BPE assessments were performed on a 4-point scale, in accordance with BI-RADS categories. Additional 3D quantitative MRI BPE analysis was performed using a previously published in-house technique. Spearman's correlation test and linear regression analysis was performed (SPSS, v. 24). The median time interval between breast MRI and 18F-FDG PET/CT evaluation was 3 days (range, 0-6 days). BPU SUVmax mean value was 1.6 (SD, 0.53). Minimum and maximum BPU SUVmax values were 0.71 and 4.0. The BPU SUVmax values significantly correlated with both the qualitative and quantitative measurements of BPE, respectively (r(71) = 0.59, P Qualitatively assessed high BPE group (BI-RADS 3/4) had significantly

  16. A large N400 but no BOLD effect--comparing source activations of semantic priming in simultaneous EEG-fMRI.

    Directory of Open Access Journals (Sweden)

    Sebastian Geukes

    Full Text Available Numerous studies have reported neurophysiological effects of semantic priming in electroencephalography (EEG and in functional magnetic resonance imaging (fMRI. Because of differing methodological constraints, the comparability of the observed effects remains unclear. To directly compare EEG and fMRI effects and neural sources of semantic priming, we conducted a semantic word-picture priming experiment while measuring EEG and fMRI simultaneously. The visually presented primes were pseudowords, words unrelated to the target, semantically related words and the identical names of the target. Distributed source analysis of the event-related potentials (ERPs successfully revealed a large effect of semantic prime-target relatedness (the N400 effect, which was driven by activations in a left-temporal source region. However, no significantly differing activations between priming conditions were found in the fMRI data. Our results support the notion that, for joint interpretations of existing EEG and fMRI studies of semantic priming, we need to fully appreciate the respective methodological limitations. Second, they show that simultaneous EEG-fMRI, including ERP source localization, is a feasible and promising methodological advancement for the investigation of higher-cognitive processes. Third, they substantiate the finding that, compared to fMRI, ERPs are often more sensitive to subtle cognitive effects.

  17. Anti-infection activity of nanostructured titanium percutaneous implants with a postoperative infection model

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Jing; Li, Yiting; Liu, Zhiyuan; Qu, Shuxin; Lu, Xiong; Wang, Jianxin; Duan, Ke; Weng, Jie; Feng, Bo, E-mail: fengbo@swjtu.edu.cn

    2015-07-30

    Highlights: • We prepared three titania nanotubes (TNT-50, TNT-100, TNT-150) on titanium surfaces by anodization. • TNT-100 had the highest antibacterial efficiency under the visible light. • The immersion test in the culture medium suggested that TNT can adsorb more proteins than pTi. • TNT implants inhibited the infection risk and enhanced tissue integration of the percutaneous implants compared to pTi. - Abstract: The titanium percutaneous implants were widely used in clinic; however, they have an increased risk of infection since they breach the skin barrier. Lack of complete skin integration with the implants can cause infection and implant removal. In this work, three titania nanotubes (TNT) with different diameters, 50 nm (TNT-50), 100 nm (TNT-100) and 150 nm (TNT-150) arrays were prepared on titanium surfaces by anodization, pure titanium (pTi) was used as control. Samples were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), and contact angle analysis. The antibacterial efficiency of TNT was evaluated in vitro against Staphylococcus aureus under the visible light. The results indicated that TNT-100 had the highest antibacterial efficiency under the visible light. Subsequently, TNT implants and pTi implants were placed subcutaneously to the dorsum of New Zealand White rabbits, 10{sup 8} CFU S. aureus was inoculated into the implant sites 4 h after surgery. The TNF-alpha and IL-1alpha were determined using enzyme linked immunoassay (ELISA). TNT implants revealed less inflammatory factor release than pTi implants with or without injected S. aureus liquid. According to the histological results, the TNT implants displayed excellent tissue integration. Whereas, pTi implants were surrounded with fibrotic capsule, and the skin tissue was almost separated from the implant surface. Therefore, the TNT significantly inhibited the infection risk and enhanced tissue integration of the percutaneous implants compared to pTi. The

  18. Relational complexity modulates activity in the prefrontal cortex during numerical inductive reasoning: an fMRI study.

    Science.gov (United States)

    Feng, Xiao; Peng, Li; Chang-Quan, Long; Yi, Lei; Hong, Li

    2014-09-01

    Most previous studies investigating relational reasoning have used visuo-spatial materials. This fMRI study aimed to determine how relational complexity affects brain activity during inductive reasoning, using numerical materials. Three numerical relational levels of the number series completion task were adopted for use: 0-relational (e.g., "23 23 23"), 1-relational ("32 30 28") and 2-relational ("12 13 15") problems. The fMRI results revealed that the bilateral dorsolateral prefrontal cortex (DLPFC) showed enhanced activity associated with relational complexity. Bilateral inferior parietal lobule (IPL) activity was greater during the 1- and 2-relational level problems than during the 0-relational level problems. In addition, the left fronto-polar cortex (FPC) showed selective activity during the 2-relational level problems. The bilateral DLPFC may be involved in the process of hypothesis generation, whereas the bilateral IPL may be sensitive to calculation demands. Moreover, the sensitivity of the left FPC to the multiple relational problems may be related to the integration of numerical relations. The present study extends our knowledge of the prefrontal activity pattern underlying numerical relational processing.

  19. An fMRI study of sex differences in regional activation to a verbal and a spatial task.

    Science.gov (United States)

    Gur, R C; Alsop, D; Glahn, D; Petty, R; Swanson, C L; Maldjian, J A; Turetsky, B I; Detre, J A; Gee, J; Gur, R E

    2000-09-01

    Sex differences in cognitive performance have been documented, women performing better on some phonological tasks and men on spatial tasks. An earlier fMRI study suggested sex differences in distributed brain activation during phonological processing, with bilateral activation seen in women while men showed primarily left-lateralized activation. This blood oxygen level-dependent fMRI study examined sex differences (14 men, 13 women) in activation for a spatial task (judgment of line orientation) compared to a verbal-reasoning task (analogies) that does not typically show sex differences. Task difficulty was manipulated. Hypothesized ROI-based analysis documented the expected left-lateralized changes for the verbal task in the inferior parietal and planum temporal regions in both men and women, but only men showed right-lateralized increase for the spatial task in these regions. Image-based analysis revealed a distributed network of cortical regions activated by the tasks, which consisted of the lateral frontal, medial frontal, mid-temporal, occipitoparietal, and occipital regions. The activation was more left lateralized for the verbal and more right for the spatial tasks, but men also showed some left activation for the spatial task, which was not seen in women. Increased task difficulty produced more distributed activation for the verbal and more circumscribed activation for the spatial task. The results suggest that failure to activate the appropriate hemisphere in regions directly involved in task performance may explain certain sex differences in performance. They also extend, for a spatial task, the principle that bilateral activation in a distributed cognitive system underlies sex differences in performance. Copyright 2000 Academic Press.

  20. ACR/EULAR Definitions of Remission Are Associated with Lower Residual Inflammatory Activity Compared with DAS28 Remission on Hand MRI in Rheumatoid Arthritis.

    Science.gov (United States)

    Lisbona, Maria Pilar; Solano, Albert; Ares, Jesús; Almirall, Miriam; Salman-Monte, Tarek Carlos; Maymó, Joan

    2016-09-01

    To determine the level of residual inflammation [synovitis, bone marrow edema (BME), tenosynovitis, and total inflammation] quantified by hand magnetic resonance imaging (h-MRI) in patients with rheumatoid arthritis (RA) in remission according to 3 different definitions of clinical remission, and to compare these remission definitions. A cross-sectional study. To assess the level of residual MRI inflammation in remission, cutoff levels associated to remission and median scores of MRI residual inflammatory lesions were calculated. Data from an MRI register of patients with RA who have various levels of disease activity were used. These were used for the analyses: synovitis, BME according to the Rheumatoid Arthritis Magnetic Resonance Imaging Scoring system, tenosynovitis, total inflammation, and disease activity composite measures recorded at the time of MRI. Receiver-operating characteristic analysis was used to identify the best cutoffs associated with remission for each inflammatory lesion on h-MRI. Median values of each inflammatory lesion for each definition of remission were also calculated. A total of 388 h-MRI sets of patients with RA with different levels of disease activity, 130 in remission, were included. Cutoff values associated with remission according to the Simplified Disease Activity Index (SDAI) ≤ 3.3 and the Boolean American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) definitions for BME and tenosynovitis (1 and 3, respectively) were lower than BME and tenosynovitis (2 and 5, respectively) for the Disease Activity Score on 28 joints (DAS28) ≤ 2.6. Median scores for synovitis, BME, and total inflammation were also lower for the SDAI and Boolean ACR/EULAR remission criteria compared with DAS28. Patients with RA in remission according to the SDAI and Boolean ACR/EULAR definitions showed lower levels of MRI-detected residual inflammation compared with DAS28.

  1. Brain activity modification produced by a single radioelectric asymmetric brain stimulation pulse: a new tool for neuropsychiatric treatments. Preliminary fMRI study

    Directory of Open Access Journals (Sweden)

    Castagna A

    2011-10-01

    Full Text Available Salvatore Rinaldi1,2, Vania Fontani1, Alessandro Castagna1 1Department of Neuro-Psycho-Physio Pathology, Rinaldi Fontani Institute, Florence, Italy; 2Medical School of Occupational Medicine, University of Florence, Florence, Italy Purpose: Radioelectric asymmetric brain stimulation technology with its treatment protocols has shown efficacy in various psychiatric disorders. The aim of this work was to highlight the mechanisms by which these positive effects are achieved. The current study was conducted to determine whether a single 500-millisecond radioelectric asymmetric conveyor (REAC brain stimulation pulse (BSP, applied to the ear, can effect a modification of brain activity that is detectable using functional magnetic resonance imaging (fMRI. Methods: Ten healthy volunteers, six females and four males, underwent fMRI during a simple finger-tapping motor task before and after receiving a single 500-millisecond REAC-BSP. Results: The fMRI results indicate that the average variation in task-induced encephalic activation patterns is lower in subjects following the single REAC pulse. Conclusion: The current report demonstrates that a single REAC-BSP is sufficient to modulate brain activity in awake subjects, able to be measured using fMRI. These initial results open new perspectives into the understanding of the effects of weak and brief radio pulses upon brain activity, and provide the basis for further indepth studies using REAC-BSP and fMRI. Keywords: fMRI, brain stimulation, brain modulation, REAC, neuropsychiatric treatments

  2. Leptin serves as an upstream activator of an obligatory signaling cascade in the embryo-implantation process.

    Science.gov (United States)

    Ramos, M P; Rueda, B R; Leavis, P C; Gonzalez, R R

    2005-02-01

    Leptin is essential for mouse reproduction, but the exact roles it serves are yet to be determined. Treatment of cultured endometrial cells with leptin increases the level of beta3-integrin, IL-1, leukemia inhibitory factor, and their corresponding receptors. These leptin-induced effects are eliminated by inhibitors of leptin receptor (OB-R) signaling. Herein the impact of blocking leptin/OB-R signaling in the mouse endometrium was assessed. Intrauterine injection of either leptin peptide antagonists (LPA-1 or -2) or OB-R antibody on d 3 of pregnancy impaired mouse implantation in comparison to intrauterine injection of scrambled peptides (LPA-Sc) or species-matched IgGs. Significant reduction in the number of implantation sites and uterine horns with implanted embryos was found after intrauterine injection of LPA-1 (1 of 22) vs. LPA-1Sc (11 of 15) and LPA-2 (3 of 17) vs. LPA-2Sc (14 of 16). The impact of disruption of leptin signaling on the endometrial expression of several molecules in pregnant mice was assessed by Western blot, immunohistochemistry, and confocal microscopy. Disruption of leptin signaling resulted in a significant reduction of IL-1 receptor type I, leukemia inhibitory factor, vascular endothelial growth factor receptor 2, and beta3-integrin levels. The levels of colony stimulating factor-1 receptor and OB-R were unaltered after treatment with LPAs compared with controls. Expression of OB-R protein was pregnancy dependent and found only in glandular epithelium after implantation occurred. Our findings support previous observations that leptin signaling is critical to the implantation process and suggest that molecules downstream of leptin-activated receptor may serve obligatory roles in endometrial receptivity and successful implantation.

  3. Defining optimal tracer activities in pediatric oncologic whole-body {sup 18}F-FDG-PET/MRI

    Energy Technology Data Exchange (ETDEWEB)

    Gatidis, Sergios; Schmidt, Holger; Nikolaou, Konstantin; Schwenzer, Nina F.; Schaefer, Juergen F. [University of Tuebingen, Department of Radiology, Diagnostic and Interventional Radiology, Tuebingen (Germany); La Fougere, Christian [University of Tuebingen, Department of Radiology, Nuclear Medicine, Tuebingen (Germany)

    2016-12-15

    To explore the feasibility of reducing administered tracer activities and to assess optimal activities for combined {sup 18}F-FDG-PET/MRI in pediatric oncology. 30 {sup 18}F-FDG-PET/MRI examinations were performed on 24 patients with known or suspected solid tumors (10 girls, 14 boys, age 12 ± 5.6 [1-18] years; PET scan duration: 4 min per bed position). Low-activity PET images were retrospectively simulated from the originally acquired data sets using randomized undersampling of list mode data. PET data of different simulated administered activities (0.25-2.5 MBq/kg body weight) were reconstructed with or without point spread function (PSF) modeling. Mean and maximum standardized uptake values (SUV{sub mean} and SUV{sub max}) as well as SUV variation (SUV{sub var}) were measured in physiologic organs and focal FDG-avid lesions. Detectability of organ structures and of focal {sup 18}F-FDG-avid lesions as well as the occurrence of false-positive PET lesions were assessed at different simulated tracer activities. Subjective image quality steadily declined with decreasing tracer activities. Compared to the originally acquired data sets, mean relative deviations of SUV{sub mean} and SUV{sub max} were below 5 % at {sup 18}F-FDG activities of 1.5 MBq/kg or higher. Over 95 % of anatomic structures and all pathologic focal lesions were detectable at 1.5 MBq/kg {sup 18}F-FDG. Detectability of anatomic structures and focal lesions was significantly improved using PSF. No false-positive focal lesions were observed at tracer activities of 1 MBq/kg {sup 18}F-FDG or higher. Administration of {sup 18}F-FDG activities of 1.5 MBq/kg is, thus, feasible without obvious diagnostic shortcomings, which is equivalent to a dose reduction of more than 50 % compared to current recommendations. Significant reduction in administered {sup 18}F-FDG tracer activities is feasible in pediatric oncologic PET/MRI. Appropriate activities of {sup 18}F-FDG or other tracers for specific clinical

  4. Towards simultaneous achievement of carrier activation and crystallinity in Ge and GeSn with heated phosphorus ion implantation: An optical study

    Science.gov (United States)

    D'Costa, Vijay Richard; Wang, Lanxiang; Wang, Wei; Lim, Sin Leng; Chan, Taw Kuei; Chua, Lye Hing; Henry, Todd; Zou, Wei; Hatem, Christopher; Osipowicz, Thomas; Tok, Eng Soon; Yeo, Yee-Chia

    2014-09-01

    We have investigated the optical properties of Ge and GeSn alloys implanted with phosphorus ions at 400 °C by spectroscopic ellipsometry from far-infrared to ultraviolet. The dielectric response of heated GeSn implants displays structural and transport properties similar to those of heated Ge implants. The far-infrared dielectric function of as-implanted Ge and GeSn shows the typical free carrier response which can be described by a single Drude oscillator. Bulk Ge-like critical points E1, E1 + Δ1, E0', and E2 are observed in the visible-UV dielectric function of heated Ge and GeSn indicating single crystalline quality of the as-implanted layers. Although the implantation at 400 °C recovers crystallinity in both Ge and GeSn, an annealing step is necessary to enhance the carrier activation.

  5. Decrease in fMRI brain activation during working memory performed after sleeping under 10 lux light.

    Science.gov (United States)

    Kang, Seung-Gul; Yoon, Ho-Kyoung; Cho, Chul-Hyun; Kwon, Soonwook; Kang, June; Park, Young-Min; Lee, Eunil; Kim, Leen; Lee, Heon-Jeong

    2016-11-09

    The aim of this study was to investigate the effect of exposure to dim light at night (dLAN) when sleeping on functional brain activation during a working-memory tasks. We conducted the brain functional magnetic resonance imaging (fMRI) analysis on 20 healthy male subjects. All participants slept in a polysomnography laboratory without light exposure on the first and second nights and under a dim-light condition of either 5 or 10 lux on the third night. The fMRI scanning was conducted during n-back tasks after second and third nights. Statistical parametric maps revealed less activation in the right inferior frontal gyrus (IFG) after exposure to 10-lux light. The brain activity in the right and left IFG areas decreased more during the 2-back task than during the 1- or 0-back task in the 10-lux group. The exposure to 5-lux light had no significant effect on brain activities. The exposure to dLAN might influence the brain function which is related to the cognition.

  6. Cerebral activation during thermal stimulation of patients who have burning mouth disorder: an fMRI study.

    Science.gov (United States)

    Albuquerque, Romulo J C; de Leeuw, Reny; Carlson, Charles R; Okeson, Jeffrey P; Miller, Craig S; Andersen, Anders H

    2006-06-01

    The pathophysiology of burning mouth disorder (BMD) is not clearly understood, but central neuropathic mechanisms are thought to be involved. The aim of this study was to gain insight into the pathophysiology associated with BMD by using functional magnetic resonance imaging (fMRI). Areas of brain activation following thermal stimulation of the trigeminal nerve of eight female patients with BMD (mean age 49.1+/-10.1) were mapped using fMRI and compared with those of eight matched pain-free volunteers (mean age 50.3+/-12.3). Qualitative and quantitative differences in brain activation patterns between the two study groups were demonstrated. BMD patients displayed greater fractional signal changes in the right anterior cingulate cortex (BA 32/24) and bilateral precuneus than did controls (p<0.005). The control group showed larger fractional signal changes in the bilateral thalamus, right middle frontal gyrus, right pre-central gyrus, left lingual gyrus, and cerebellum than did the BMD patients (p<0.005). In addition, BMD patients had less volumetric activation throughout the entire brain compared to the control group. Overall, BMD patients displayed brain activation patterns similar to those of patients with other neuropathic pain conditions and appear to process thermal painful stimulation to the trigeminal nerve qualitatively and quantitatively different than pain-free individuals. These findings suggest that brain hypoactivity may be an important feature in the pathophysiology of BMD.

  7. Surface Engineering for Bone Implants: A Trend from Passive to Active Surfaces

    Directory of Open Access Journals (Sweden)

    John Jansen

    2012-07-01

    Full Text Available The mechanical and biological properties of bone implants need to be optimal to form a quick and firm connection with the surrounding environment in load bearing applications. Bone is a connective tissue composed of an organic collagenous matrix, a fine dispersion of reinforcing inorganic (calcium phosphate nanocrystals, and bone-forming and -degrading cells. These different components have a synergistic and hierarchical structure that renders bone tissue properties unique in terms of hardness, flexibility and regenerative capacity. Metallic and polymeric materials offer mechanical strength and/or resilience that are required to simulate bone tissue in load-bearing applications in terms of maximum load, bending and fatigue strength. Nevertheless, the interaction between devices and the surrounding tissue at the implant interface is essential for success or failure of implants. In that respect, coatings can be applied to facilitate the process of bone healing and obtain a continuous transition from living tissue to the synthetic implant. Compounds that are inspired by inorganic (e.g., hydroxyapatite crystals or organic (e.g., collagen, extracellular matrix components, enzymes components of bone tissue, are the most obvious candidates for application as implant coating to improve the performance of bone implants. This review provides an overview of recent trends and strategies in surface engineering that are currently investigated to improve the biological performance of bone implants in terms of functionality and biological efficacy.

  8. 3D-EAUS and MRI in the Activity of Anal Fistulas in Crohn's Disease

    OpenAIRE

    Maria Eleonora Alabiso; Francesca Iasiello; Gianluca Pellino; Aniello Iacomino; Luca Roberto; Antonio Pinto; Gabriele Riegler; Francesco Selvaggi; Alfonso Reginelli

    2015-01-01

    Aim. This study aspires to assess the role of 3D-Endoanal Ultrasound (3D-EAUS) and Magnetic Resonance Imaging (MRI) in preoperative evaluation of the primary tract and internal opening of perianal fistulas, of secondary extensions and abscess. Methods. During 2014, 51 Crohn's disease patients suspected for perianal fistula were enrolled. All patients underwent physical examination with both the methods and subsequent surgery. Results. In the evaluation of CD perianal fistulas, there are no si...

  9. Microwave annealing, a low-thermal-budget process for dopant activation in phosphorus-implanted MOSFET devices

    Science.gov (United States)

    Lim, Cheol-Min; Cho, Won-Ju

    2016-09-01

    In this work, we investigated a low-thermal-budget dopant activation process based on microwave annealing (MWA) of phosphorus ions implanted by plasma doping and compared the proposed technique with the conventional furnace annealing and the rapid thermal annealing processes. We fabricated p-n junction diodes and metal-oxide-semiconductor field-effect transistors (MOSFETs) on silicon and silicon-on-insulator substrates, respectively, in order to examine the dopant activation resulting from MWA. The investigated low-thermal-budget MWA technique proved effective for implanted dopant atom activation and diffusion suppression. In addition, a good interface property between the gate oxide and the silicon channel was achieved. Thus, low-thermal-budget MWA is a promising and effective method for the fabrication of highly-integrated semiconductor devices.

  10. Transient and sustained BOLD signal time courses affect the detection of emotion-related brain activation in fMRI.

    Science.gov (United States)

    Paret, Christian; Kluetsch, Rosemarie; Ruf, Matthias; Demirakca, Traute; Kalisch, Raffael; Schmahl, Christian; Ende, Gabriele

    2014-12-01

    A tremendous amount of effort has been dedicated to unravel the functional neuroanatomy of the processing and regulation of emotion, resulting in a well-described picture of limbic, para-limbic and prefrontal regions involved. Studies applying functional magnetic resonance imaging (fMRI) often use the block-wise presentation of stimuli with affective content, and conventionally model brain activation as a function of stimulus or task duration. However, there is increasing evidence that regional brain responses may not always translate to task duration and rather show stimulus onset-related transient time courses. We assume that brain regions showing transient responses cannot be detected in block designs using a conventional fMRI analysis approach. At the same time, the probability of detecting these regions with conventional analyses may be increased when shorter stimulus timing or a more intense stimulation during a block is used. In a within-subject fMRI study, we presented aversive pictures to 20 healthy subjects and investigated the effect of experimental design (i.e. event-related and block design) on the detection of brain activation in limbic and para-limbic regions of interest of emotion processing. In addition to conventional modeling of sustained activation during blocks of stimulus presentation, we included a second response function into the general linear model (GLM), suited to detect transient time courses at block onset. In the conventional analysis, several regions like the amygdala, thalamus and periaqueductal gray were activated irrespective of design. However, we found a positive BOLD response in the anterior insula (AI) in event-related but not in block-design analyses. GLM analyses suggest that this difference may result from a transient response pattern which cannot be captured by the conventional fMRI analysis approach. Our results indicate that regions with a transient response profile like the AI can be missed in block designs if analyses

  11. X线钼靶、高频超声及MRI对硅胶假体隆乳术后破裂的诊断价值%The Diagnosis of Mammography, High-frequency Ultrasound and MRI in Silicone Breast Implant Rupture

    Institute of Scientific and Technical Information of China (English)

    杜牧; 曹满瑞; 谢肇峰; 刘涛

    2014-01-01

    目的:探讨X线钼靶、高频超声及MRI对硅胶假体隆乳术后破裂的诊断价值。方法对28例56只乳腺硅胶假体隆乳术后患者的X线钼靶、高频超声及MRI资料进行回顾性研究,分析其影像表现及对假体囊内破裂及囊外破裂的诊断价值。结果 X线不能完整显示假体(0%),高频超声及MRI都能够完整显示假体(均为100%);对囊外破裂,X线钼靶、高频超声及MRI都能显示(均为7.1%,4/56); X线不能显示囊内破裂(0%), MRI(32.1%,18/56)对囊内破裂的检出率高于超声(21.4%,12/56)(P=0.031)。结论对硅胶假体破裂的诊断,X线钼靶并不是令人满意的方法,超声是经济高效的检查方法,而MRI是最理想的检查方法,如经济允许,MRI可列为首选。%Objective To investigate the diagnostic value of mammography, high-frequency ultrasound and MRI in silicone breast implant rupture. Methods 28 cases with 56 breasts were included in this study, and the mammography, high-frequency ultrasound and MRI findings and its diagnostic value for silicone breast implant rupture were analyzed. Results The mammography can't show the integrity of the silicone breast implant(0%,0/56), and ultrasound and MRI can show it(100%,56/56). Both mammography, ultrasound and MRI can diagnose extracapsular rupture(7.1%,4/56). Mammography can't detect intracapsular rupture (0%,0/56),and MRI(32.1%,18/56)is better than ultrasound(21.4%,12/56)in detection of intracapsular rupture(P=0.031). Conclusion In detecting silicone breast implant rupture, mammography is a satisfied way, ultrasound is an economic and efficient way, and MRI is the most ideal way and it should be the first choice if the economy allowed.

  12. MRI Scans

    Science.gov (United States)

    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 ...

  13. Shoulder MRI

    Science.gov (United States)

    ... MRI scanners are air-conditioned and well-lit. Music may be played through the headphones to help ... that magnetic resonance imaging harms the fetus, pregnant women usually are advised not to have an MRI ...

  14. Regional Homogeneity of Resting-state fMRI Contributes to Both Neurovascular and Task Activation Variations

    Science.gov (United States)

    Yuan, Rui; Di, Xin; Kim, Eun H.; Barik, Sabrina; Rypma, Bart; Biswal, Bharat B.

    2013-01-01

    The task induced blood oxygenation level dependent signal changes observed using functional magnetic resonance imaging (fMRI) is critically dependent on the relationship between neuronal activity and hemodynamic response. Therefore, understanding the nature of neurovascular coupling is important when interpreting fMRI signal changes evoked via task. In this study, we used regional homogeneity (ReHo), a measure of local synchronization of the BOLD time series, to investigate whether the similarities of one voxel with the surrounding voxels is a property of neurovascular coupling. FMRI scans were obtained from fourteen subjects during bilateral finger tapping (FTAP), digit-symbol substitution (DSST) and periodic breath holding (BH) paradigm. A resting-state scan was also obtained for each of the subjects for 4 minutes using identical imaging parameters. Inter-voxel correlation analyses were conducted between the resting-state ReHo, resting-state amplitude of low frequency fluctuations (ALFF), breath hold (BH) responses and task activations within the masks related to task activations. There was a reliable mean voxel-wise spatial correlation between ReHo and other neurovascular variables (BH responses and ALFF). We observed a moderate correlation between ReHo and task activations (FTAP: r = 0.32; DSST: r = 0.22) within the task positive network and a small yet reliable correlation within the default mode network (DSST: r = −0.08). Subsequently, a linear regression was used to estimate the contribution of ReHo, ALFF and BH responses to the task activated voxels. The unique contribution of ReHo was minimal. The results suggest that regional synchrony of the BOLD activity is a property that can explain the variance of neurovascular coupling and task activations; but its contribution to task activations can be accounted for by other neurovascular factors such as the ALFF. PMID:23969197

  15. Assessment of muscle function using hybrid PET/MRI: comparison of {sup 18}F-FDG PET and T2-weighted MRI for quantifying muscle activation in human subjects

    Energy Technology Data Exchange (ETDEWEB)

    Haddock, Bryan; Holm, Soeren; Poulsen, Jakup M.; Enevoldsen, Lotte H.; Larsson, Henrik B.W.; Kjaer, Andreas; Suetta, Charlotte [Rigshospitalet Glostrup, Copenhagen University Hospital, Department of Clinical Physiology, Nuclear Medicine and PET, Glostrup (Denmark)

    2017-04-15

    The aim of this study was to determine the relationship between relative glucose uptake and MRI T{sub 2} changes in skeletal muscles following resistance exercise using simultaneous PET/MRI scans. Ten young healthy recreationally active men (age 21 - 28 years) were injected with {sup 18}F-FDG while activating the quadriceps of one leg with repeated knee extension exercises followed by hand-grip exercises for one arm. Immediately following the exercises, the subjects were scanned simultaneously with {sup 18}F-FDG PET/MRI and muscle groups were evaluated for increases in {sup 18}F-FDG uptake and MRI T{sub 2} values. A significant linear correlation between {sup 18}F-FDG uptake and changes in muscle T{sub 2} (R {sup 2} = 0.71) was found. for both small and large muscles and in voxel to voxel comparisons. Despite large intersubject differences in muscle recruitment, the linear correlation between {sup 18}F-FDG uptake and changes in muscle T{sub 2} did not vary among subjects. This is the first assessment of skeletal muscle activation using hybrid PET/MRI and the first study to demonstrate a high correlation between {sup 18}F-FDG uptake and changes in muscle T{sub 2} with physical exercise. Accordingly, it seems that changes in muscle T{sub 2} may be used as a surrogate marker for glucose uptake and lead to an improved insight into the metabolic changes that occur with muscle activation. Such knowledge may lead to improved treatment strategies in patients with neuromuscular pathologies such as stroke, spinal cord injuries and muscular dystrophies. (orig.)

  16. Effects of methylphenidate on resting-state brain activity in normal adults: an fMRI study

    Institute of Scientific and Technical Information of China (English)

    Yihong Zhu; Bin Gao; Jianming Hua; Weibo Liu; Yichao Deng; Lijie Zhang; Biao Jiang

    2013-01-01

    Methylphenidate (MPH) is one of the most commonly used stimulants for the treatment of attention deficit hyperactivity disorder (ADHD).Although several studies have evaluated the effects of MPH on human brain activation during specific cognitive tasks using functional magnetic resonance imaging (fMRI),few studies have focused on spontaneous brain activity.In the current study,we investigated the effect of MPH on the intra-regional synchronization of spontaneous brain activity during the resting state in 18normal adult males.A handedness questionnaire and the Wechsler Adult Intelligence Scale were applied before medication,and a resting-state fMRI scan was obtained 1 h after medication (20 mg MPH or placebo,order counterbalanced between participants).We demonstrated that:(1) there were no significant differences in the performance of behavioral tasks between the MPH and placebo groups; (2) the left middle and superior temporal gyri had stronger MPH-related regional homogeneity (ReHo); and (3) the left lingual gyrus had weaker MPH-related ReHo.Our findings showed that the ReHo in some brain areas changes with MPH compared to placebo in normal adults,even though there are no behavioral differences.This method can be applied to patients with mental illness who may be treated with MPH,and be used to compare the difference between patients taking MPH and normal participants,to help reveal the mechanism of how MPH works.

  17. Indications and outcome of subtotal petrosectomy for active middle ear implants.

    Science.gov (United States)

    Verhaert, Nicolas; Mojallal, Hamidreza; Schwab, Burkard

    2013-03-01

    The aim of this study was to describe the outcome and possible complications of subtotal petrosectomy (SP) for Vibrant Soundbridge (VSB) device surgery in a tertiary referral center. A secondary objective was the evaluation of hearing results in a subgroup of subjects who received the VSB device. Between 2009 and early 2011, 22 adult subjects with chronic otitis media (COM) underwent a SP, blind sac closure of the external auditory canal and abdominal fat obliteration to facilitate the application of an active middle ear implant (AMEI) in a staged procedure. Indications consisted of mixed hearing loss after previous tympanomastoplasty and failure of hearing rehabilitation with a hearing aid or bone conduction device in COM. Pre- and postoperative pure-tone audiograms were analyzed in respect to deterioration of inner ear function, unaided and aided (hearing aid, bone-anchored hearing aid and VSB) speech audiograms were compared to verify improvements in communications skills and functional gains. Incidence and type of complications were reviewed. No significant change was observed regarding mean bone conduction thresholds after the first stage procedure. Some minor wound healing problems were noted. Speech perception using the VSB (n = 16) showed a mean aided speech discrimination at 65-dB SPL of 75 % [standard deviation (SD) 28.7], at 80-dB SPL of 90 % (SD 25.1). Our results suggest that for selected patients with open mastoid cavities and chronic middle ear disease, SP with abdominal fat obliteration is an effective and safe technique to facilitate safe AMEI placement.

  18. Volitional reduction of anterior cingulate cortex activity produces decreased cue craving in smoking cessation: a preliminary real-time fMRI study.

    Science.gov (United States)

    Li, Xingbao; Hartwell, Karen J; Borckardt, Jeffery; Prisciandaro, James J; Saladin, Michael E; Morgan, Paul S; Johnson, Kevin A; Lematty, Todd; Brady, Kathleen T; George, Mark S

    2013-07-01

    Numerous research groups are now using analysis of blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI) results and relaying back information about regional activity in their brains to participants in the scanner in 'real time'. In this study, we explored the feasibility of self-regulation of frontal cortical activation using real-time fMRI (rtfMRI) neurofeedback in nicotine-dependent cigarette smokers during exposure to smoking cues. Ten cigarette smokers were shown smoking-related visual cues in a 3 Tesla MRI scanner to induce their nicotine craving. Participants were instructed to modify their craving using rtfMRI feedback with two different approaches. In a 'reduce craving' paradigm, participants were instructed to 'reduce' their craving, and decrease the anterior cingulate cortex (ACC) activity. In a separate 'increase resistance' paradigm, participants were asked to increase their resistance to craving and to increase middle prefrontal cortex (mPFC) activity. We found that participants were able to significantly reduce the BOLD signal in the ACC during the 'reduce craving' task (P=0.028). There was a significant correlation between decreased ACC activation and reduced craving ratings during the 'reduce craving' session (P=0.011). In contrast, there was no modulation of the BOLD signal in mPFC during the 'increase resistance' session. These preliminary results suggest that some smokers may be able to use neurofeedback via rtfMRI to voluntarily regulate ACC activation and temporarily reduce smoking cue-induced craving. Further research is needed to determine the optimal parameters of neurofeedback rtfMRI, and whether it might eventually become a therapeutic tool for nicotine dependence. © 2012 The Authors, Addiction Biology © 2012 Society for the Study of Addiction.

  19. Convergence of human brain mapping tools: neuronavigated TMS parameters and fMRI activity in the hand motor area.

    Science.gov (United States)

    Sarfeld, Anna-Sophia; Diekhoff, Svenja; Wang, Ling E; Liuzzi, Gianpiero; Uludağ, Kamil; Eickhoff, Simon B; Fink, Gereon R; Grefkes, Christian

    2012-05-01

    Functional magnetic resonance imaging (fMRI) and transcranial magnetic stimulation (TMS) are well-established tools for investigating the human motor system in-vivo. We here studied the relationship between movement-related fMRI signal changes in the primary motor cortex (M1) and electrophysiological properties of the hand motor area assessed with neuronavigated TMS in 17 healthy subjects. The voxel showing the highest task-related BOLD response in the left hand motor area during right hand movements was identified for each individual subject. This fMRI peak voxel in M1 served as spatial target for coil positioning during neuronavigated TMS. We performed correlation analyses between TMS parameters, BOLD signal estimates and effective connectivity parameters of M1 assessed with dynamic causal modeling (DCM). The results showed a negative correlation between the movement-related BOLD signal in left M1 and resting as well as active motor threshold (MT) obtained for left M1. The DCM analysis revealed that higher excitability of left M1 was associated with a stronger coupling between left supplementary motor area (SMA) and M1. Furthermore, BOLD activity in left M1 correlated with ipsilateral silent period (ISP), i.e. the stronger the task-related BOLD response in left M1, the higher interhemispheric inhibition effects targeting right M1. DCM analyses revealed a positive correlation between the coupling of left SMA with left M1 and the duration of ISP. The data show that TMS parameters assessed for the hand area of M1 do not only reflect the intrinsic properties at the stimulation site but also interactions with remote areas in the human motor system.

  20. Decoding fMRI events in sensorimotor motor network using sparse paradigm free mapping and activation likelihood estimates.

    Science.gov (United States)

    Tan, Francisca M; Caballero-Gaudes, César; Mullinger, Karen J; Cho, Siu-Yeung; Zhang, Yaping; Dryden, Ian L; Francis, Susan T; Gowland, Penny A

    2017-08-16

    Most functional MRI (fMRI) studies map task-driven brain activity using a block or event-related paradigm. Sparse paradigm free mapping (SPFM) can detect the onset and spatial distribution of BOLD events in the brain without prior timing information, but relating the detected events to brain function remains a challenge. In this study, we developed a decoding method for SPFM using a coordinate-based meta-analysis method of activation likelihood estimation (ALE). We defined meta-maps of statistically significant ALE values that correspond to types of events and calculated a summation overlap between the normalized meta-maps and SPFM maps. As a proof of concept, this framework was applied to relate SPFM-detected events in the sensorimotor network (SMN) to six motor functions (left/right fingers, left/right toes, swallowing, and eye blinks). We validated the framework using simultaneous electromyography (EMG)-fMRI experiments and motor tasks with short and long duration, and random interstimulus interval. The decoding scores were considerably lower for eye movements relative to other movement types tested. The average successful rate for short and long motor events were 77 ± 13% and 74 ± 16%, respectively, excluding eye movements. We found good agreement between the decoding results and EMG for most events and subjects, with a range in sensitivity between 55% and 100%, excluding eye movements. The proposed method was then used to classify the movement types of spontaneous single-trial events in the SMN during resting state, which produced an average successful rate of 22 ± 12%. Finally, this article discusses methodological implications and improvements to increase the decoding performance. Hum Brain Mapp, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  1. Diffusion and Electrical Activation After a Rapid Thermal Annealing of an As and B-Co-Implanted Polysilicon Layer

    Science.gov (United States)

    Gontrand, C.; Sellitto, P.; Tabikh, S.; Latreche, S.; Kaminski, A.

    1997-01-01

    This work provides an experimental insight into the physical mechanisms involved in the co-diffusion of arsenic and boron in polysilicon/monocrystalline Si bilayers, during the formation of shallow N^+ emitters for the BiCMOS technology. The RTA-induced redistribution of As and B successively implanted in a 380 nm LPCVD polysilicon layer is studied by SIMS measurements. Hall effect, as well as sheet resistance measurements, show that the electrical activation of dopants in the co-implanted structures is satisfactory from a RTA temperature of 1100 °C. Nous présentons ici un travail expérimental mettant en évidence les mécanismes physiques intervenant dans la co-diffusion de l'arsenic et du bore dans une bicouche polysilicium sur silicium polycrystallin, durant la formation des émetteurs étroits N^+ destinés à la technologie BiCMOS. La redistribution de As et B induite par un RTA, successivement implantés dans une couche de polysilicium de 380 nm, est appréhendée par des mesures SIMS. Des mesures par effet Hall et par résistances par carrés mettent en évidence que l'activité électrique des dopants dans les structures implantées est satisfaisante à partir d'une température de 1100 °C.

  2. An implantable two axis micromanipulator made with a 3D printer for recording neural activity in free-swimming fish.

    Science.gov (United States)

    Rogers, Loranzie S; Van Wert, Jacey C; Mensinger, Allen F

    2017-08-15

    Chronically implanted electrodes allow monitoring neural activity from free moving animals. While a wide variety of implanted headstages, microdrives and electrodes exist for terrestrial animals, few have been developed for use with aquatic animals. A two axis micromanipulator was fabricated with a Formlabs 3D printer for implanting electrodes into free-swimming oyster toadfish (Opsanus tau). The five piece manipulator consisted of a base, body, electrode holder, manual screw drive and locking nut. The manipulator measured approximately 25×20×30mm (l×w×h) and weighed 5.28g after hand assembly. Microwire electrodes were inserted successfully with the manipulator to record high fidelity signals from the anterior lateral line nerve of the toadfish. The micromanipulator allowed the chronically implanted electrodes to be repositioned numerous times to record from multiple sites and extended successful recording time in the toadfish by several days. Three dimensional printing allowed an inexpensive (<$US 5 material), two axis micromanipulator to be printed relatively rapidly (<2h) to successfully record from multiple sites in the anterior lateral line nerve of free-swimming toadfish. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Brain necrosis after permanent low-activity iodine-125 implants: case report and review of toxicity from focal radiation.

    Science.gov (United States)

    Bampoe, J; Nag, S; Leung, P; Laperriere, N; Bernstein, M

    2000-01-01

    Focal irradiation has emerged as a useful modality in the management of malignant brain tumors. Its main limitation is radiation necrosis. We report on the radiation dose distribution in the cerebellum of a patient who developed imaging and autopsy diagnosis of radiation necrosis after permanent iodine-125 implants for a solitary osseous plasmacytoma of her left occipital condyle. A 55-year-old woman initially presented with neck and occipital pain and a lytic lesion of her left occipital condyle. A cytological diagnosis of solitary osseous plasmacytoma was made by transpharyngeal needle biopsy. After an initial course of external beam radiation, the patient required further treatment with systemic chemotherapy 21 months later for clinical and radiographic progression of her disease. She ultimately required subtotal surgical resection of an anaplastic plasmacytoma with intracranial extension. Permanent low-activity iodine-125 seeds were implanted in the tumor cavity. Satisfactory local control was achieved. However, clinical and imaging signs of radiation damage appeared 28 months after iodine-125 seed implantation. Progressive systemic myeloma led to her death 11 years after presentation and 9 years after seed implantation. Radiation dose distribution is described, with a discussion of toxicity from focal radiation dose escalation.

  4. A novel fMRI paradigm suggests that pedaling-related brain activation is altered after stroke

    Science.gov (United States)

    Promjunyakul, Nutta-on; Schmit, Brian D.; Schindler-Ivens, Sheila M.

    2015-01-01

    The purpose of this study was to examine the feasibility of using functional magnetic resonance imaging (fMRI) to measure pedaling-related brain activation in individuals with stroke and age-matched controls. We also sought to identify stroke-related changes in brain activation associated with pedaling. Fourteen stroke and 12 control subjects were asked to pedal a custom, MRI-compatible device during fMRI. Subjects also performed lower limb tapping to localize brain regions involved in lower limb movement. All stroke and control subjects were able to pedal while positioned for fMRI. Two control subjects were withdrawn due to claustrophobia, and one control data set was excluded from analysis due to an incidental finding. In the stroke group, one subject was unable to enter the gantry due to excess adiposity, and one stroke data set was excluded from analysis due to excessive head motion. Consequently, 81% of subjects (12/14 stroke, 9/12 control) completed all procedures and provided valid pedaling-related fMRI data. In these subjects, head motion was ≤3 mm. In both groups, brain activation localized to the medial aspect of M1, S1, and Brodmann’s area 6 (BA6) and to the cerebellum (vermis, lobules IV, V, VIII). The location of brain activation was consistent with leg areas. Pedaling-related brain activation was apparent on both sides of the brain, with values for laterality index (LI) of –0.06 (0.20) in the stroke cortex, 0.05 (±0.06) in the control cortex, 0.29 (0.33) in the stroke cerebellum, and 0.04 (0.15) in the control cerebellum. In the stroke group, activation in the cerebellum – but not cortex – was significantly lateralized toward the damaged side of the brain (p = 0.01). The volume of pedaling-related brain activation was smaller in stroke as compared to control subjects. Differences reached statistical significance when all active regions were examined together [p = 0.03; 27,694 (9,608) μL stroke; 37,819 (9,169) μL control]. When individual

  5. 去金属伪影序列对胸腰椎体金属植入患者磁共振影像的影响%To Metal Artifacts Sequence MRI in Patients Implanted for Thoracolumbar Vertebrae Metal

    Institute of Scientific and Technical Information of China (English)

    代自伦; 黄声丽

    2015-01-01

    目的:探究去金属伪影序列对胸腰椎体金属植入患者磁共振影像的影响。方法选取2014年1月-2015年1月期间我院接受治疗的25例胸腰椎(腰椎、胸椎)金属植入物患者,对所有患者进行胸腰椎磁共振常规序列和去金属伪影序列扫描,并使用配对t检验对两种序列检查的扫描时间和图像质量评分进行分析和比较。结果去金属伪影序列图像上金属植入物的周边软组织信号丢失减轻,且常规序列的图像模糊和变形情况较去金属伪影序列图像严重。常规序列图像质量评分为(3.56±0.53)分,去金属伪影序列图像质量评分为(4.22±0.67)分,比较两组间差异统计学具有意义(p<0.05)。腰椎金属伪影序列检查时间为11min53s,常规序列检查时间为9min16s,比较两组间差异统计学具有意义(p<0.05)。胸椎去金属伪影序列检查的时间为12min45s,常规序列检查时间为8min16s,比较两组间差异统计学具有意义(p<0.05)。结论去金属伪影序列检查技术能够显著改善图像的质量,并减轻金属植入物的磁共振伪影,对金属植入物患者的脊柱磁共振影响有十分重要的意义。%Objective To explore to metal artifacts sequence thoracic vertebrae in patients with metal implants affect magnetic resonance images.Methods January 2014 -2015 period January hospital treated 25 cases of thoracolumbar spine (lumbar, thoracic) in patients with metallic implants, all patients with thoracolumbar conventional MRI sequences and go metal artifact scanning sequence, and using paired t test for two sequences check scanning time and image quality scores were analyzed and compared. Results Signal to the surrounding soft tissue image sequences metal artifacts loss mitigation metal implants, and the image is blurred and deformation sequence compared to conventional metal artifacts serious image sequences. General sequence of image quality score of (3.56±0

  6. Antiurolithiatic Activity of Extract and Oleanolic Acid Isolated from the Roots of Lantana camara on Zinc Disc Implantation Induced Urolithiasis.

    Science.gov (United States)

    Vyas, Narendra; Argal, Ameeta

    2013-01-01

    The present study was done to evaluate the antiurolithiatic activity of ethanolic extract of roots (ELC 200 mg/kg) and oleanolic acid (OA 60 mg/kg, O.A. 80 mg/kg, O.A. 100 mg/kg) isolated from roots of Lantana camara in albino wistar male rats using zinc disc implantation induced urolithiatic model. The group in which only zinc disc was implanted without any treatment showed increase in calcium output (23  ± 2.7 mg/dL). Cystone receiving animals showed significant protection from such change (P urolitiasis. Thus, OA and ELC showed promising antiurolithiatic activity in dose dependant manner.

  7. [Studies on anti-implantation and hormone activity of yuehchukene, an alkaloid isolated from the root of Murraya paniculata].

    Science.gov (United States)

    Wang, N G; Guan, M Z; Lei, H P

    1990-01-01

    Oral or subcutaneous administration of yuehchukene to female mice at the dosage of 2 or 4 mg/kg.d on day 1-3 of gestation resulted in 100% anti-implantation effect. However, yuehchukene at 4 mg/kg.d was found to have no anti-implantation effect in hamsters. Allen-Doisy test showed that yuehchukene had obvious estrogenic activity. Treatment of immature mice with yuehchukene at the dosage of 2 or 4 mg/kg.d for 3 days caused an increase of uterine weight. Combined use of yuehchukene with estradiol was shown to have synergistic effect on promoting uterine growth. Experiments showed that the estrogenic activity of yuehchukene was weaker than that of estriol. The affinity of this compound for estrogen receptor was also found to be weaker than that of estriol.

  8. Dental Implant Systems

    Science.gov (United States)

    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

  9. Dental Implant Systems

    Directory of Open Access Journals (Sweden)

    Yoshiki Oshida

    2010-04-01

    Full Text Available 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.

  10. Spinal fMRI during proprioceptive and tactile tasks in healthy subjects: activity detected using cross-correlation, general linear model and independent component analysis

    Energy Technology Data Exchange (ETDEWEB)

    Valsasina, P.; Agosta, F.; Filippi, M. [Scientific Institute Ospedale San Raffaele, Neuroimaging Research Unit, Milan (Italy); Caputo, D. [Scientific Institute Fondazione Don Gnocchi, Department of Neurology, Milan (Italy); Stroman, P.W. [Queen' s University, Department of Diagnostic Radiology, Centre for Neuroscience Studies, Kingston, ON (Canada)

    2008-10-15

    Functional MRI (fMRI) of the spinal cord is able to provide maps of neuronal activity. Spinal fMRI data have been analyzed in previous studies by calculating the cross-correlation (CC) between the stimulus and the time course of every voxel and, more recently, by using the general linear model (GLM). The aim of this study was to compare three different approaches (CC analysis, GLM and independent component analysis (ICA)) for analyzing fMRI scans of the cervical spinal cord. We analyzed spinal fMRI data from healthy subjects during a proprioceptive and a tactile stimulation by using two model-based approaches, i.e., CC analysis between the stimulus shape and the time course of every voxel, and the GLM. Moreover, we applied independent component analysis, a model-free approach which decomposes the data in a set of source signals. All methods were able to detect cervical cord areas of activity corresponding to the expected regions of neuronal activations. Model-based approaches (CC and GLM) revealed similar patterns of activity. ICA could identify a component correlated to fMRI stimulation, although with a lower statistical threshold than model-based approaches, and many components, consistent across subjects, which are likely to be secondary to noise present in the data. Model-based approaches seem to be more robust for estimating task-related activity, whereas ICA seems to be useful for eliminating noise components from the data. Combined use of ICA and GLM might improve the reliability of spinal fMRI results. (orig.)

  11. Negative cerebral blood volume fMRI response coupled with Ca²⁺-dependent brain activity in a dopaminergic road map of nociception.

    Science.gov (United States)

    Hsu, Yi-Hua; Chang, Chen; Chen, Chiao-Chi V

    2014-04-15

    Decreased cerebral blood volume/flow (CBV/CBF) contributes to negative blood-oxygen-level-dependent (BOLD) functional MRI (fMRI) signals. But it is still strongly debated whether these negative BOLD or CBV/CBF signals are indicative of decreased or increased neuronal activity. The fidelity of Ca(2+) signals in reflecting neuronal excitation is well documented. However, the roles of Ca(2+) signals and Ca(2+)-dependent activity in negative fMRI signals have never been explored; an understanding of this is essential to unraveling the underlying mechanisms and correctly interpreting the hemodynamic response of interest. The present study utilized a nociception-induced negative CBV fMRI response as a model. Ca(2+) signals were investigated in vivo using Mn(2+)-enhanced MRI (MEMRI), and the downstream Ca(2+)-dependent signaling was investigated using phosphorylated cAMP response-element-binding (pCREB) immunohistology. The results showed that nociceptive stimulation led to (1) striatal CBV decreases, (2) Ca(2+) increases via the nigrostriatal pathway, and (3) substantial expression of pCREB in substantia nigra dopaminergic neurons and striatal neurons. Interestingly, the striatal negative fMRI response was abolished by blocking substantia nigra activity but was not affected by blocking the striatal activity. This suggests the importance of input activity other than output in triggering the negative CBV signals. These findings indicate that the striatal negative CBV fMRI signals are associated with Ca(2+) increases and Ca(2+)-dependent signaling along the nigrostriatal pathway. The obtained data reveal a new brain road map in response to nociceptive stimulation of hemodynamic changes in association with Ca(2+) signals within the dopaminergic system.

  12. Representational similarity encoding for fMRI: Pattern-based synthesis to predict brain activity using stimulus-model-similarities.

    Science.gov (United States)

    Anderson, Andrew James; Zinszer, Benjamin D; Raizada, Rajeev D S

    2016-03-01

    Patterns of neural activity are systematically elicited as the brain experiences categorical stimuli and a major challenge is to understand what these patterns represent. Two influential approaches, hitherto treated as separate analyses, have targeted this problem by using model-representations of stimuli to interpret the corresponding neural activity patterns. Stimulus-model-based-encoding synthesizes neural activity patterns by first training weights to map between stimulus-model features and voxels. This allows novel model-stimuli to be mapped into voxel space, and hence the strength of the model to be assessed by comparing predicted against observed neural activity. Representational Similarity Analysis (RSA) assesses models by testing how well the grand structure of pattern-similarities measured between all pairs of model-stimuli aligns with the same structure computed from neural activity patterns. RSA does not require model fitting, but also does not allow synthesis of neural activity patterns, thereby limiting its applicability. We introduce a new approach, representational similarity-encoding, that builds on the strengths of RSA and robustly enables stimulus-model-based neural encoding without model fitting. The approach therefore sidesteps problems associated with overfitting that notoriously confront any approach requiring parameter estimation (and is consequently low cost computationally), and importantly enables encoding analyses to be incorporated within the wider Representational Similarity Analysis framework. We illustrate this new approach by using it to synthesize and decode fMRI patterns representing the meanings of words, and discuss its potential biological relevance to encoding in semantic memory. Our new similarity-based encoding approach unites the two previously disparate methods of encoding models and RSA, capturing the strengths of both, and enabling similarity-based synthesis of predicted fMRI patterns.

  13. The Effects of Acupuncture Stimulation for Brain Activation and Alcohol Abstinence Self-Efficacy: Functional MRI Study

    Directory of Open Access Journals (Sweden)

    Chae Ha Yang

    2017-01-01

    Full Text Available We attempted to investigate whether acupuncture stimulation at HT7 can have an effect on brain activation patterns and alcohol abstinence self-efficacy. Thirty-four right-handed healthy subjects were recruited for this study. They were randomly assigned into two groups: the HT7 (Shenmen group and the LI5 (Yangxi group. Acupuncture stimulation was performed using a block paradigm during fMRI scanning. Additionally, the Korean version of Alcohol Abstinence Self-Efficacy Scale (AASES was used to determine the effect of acupuncture stimulation on self-efficacy to abstain from alcohol use. According to the result of fMRI group analysis, the activation induced by HT7 stimulation was found on the bilateral postcentral gyrus, inferior parietal lobule, inferior frontal gyrus, claustrum, insula, and anterior lobe of the cerebellum, as well as on the left posterior lobe of the cerebellum (p<0.001, uncorrected. According to the AASES analysis, the interaction effect for gender and treatment was marginally significant (F(1,30=4.152, p=0.050. For female group, the simple main effect of treatment was significant (F(1,11=8.040, p=0.016, indicating that the mean change score was higher in the HT7 stimulation than in the LI5 stimulation. Therefore, our study has provided evidence to support that HT7 stimulation has a positive therapeutic effect on the alcohol-related diseases.

  14. The Effects of Acupuncture Stimulation for Brain Activation and Alcohol Abstinence Self-Efficacy: Functional MRI Study

    Science.gov (United States)

    Choi, Seong Hun; Kim, Ju Sang; Ryu, Yeon Hee; Lim, Young Jin; Kim, Moon Seup; Sohn, Jeong woo; Oh, Sung Suk

    2017-01-01

    We attempted to investigate whether acupuncture stimulation at HT7 can have an effect on brain activation patterns and alcohol abstinence self-efficacy. Thirty-four right-handed healthy subjects were recruited for this study. They were randomly assigned into two groups: the HT7 (Shenmen) group and the LI5 (Yangxi) group. Acupuncture stimulation was performed using a block paradigm during fMRI scanning. Additionally, the Korean version of Alcohol Abstinence Self-Efficacy Scale (AASES) was used to determine the effect of acupuncture stimulation on self-efficacy to abstain from alcohol use. According to the result of fMRI group analysis, the activation induced by HT7 stimulation was found on the bilateral postcentral gyrus, inferior parietal lobule, inferior frontal gyrus, claustrum, insula, and anterior lobe of the cerebellum, as well as on the left posterior lobe of the cerebellum (p < 0.001, uncorrected). According to the AASES analysis, the interaction effect for gender and treatment was marginally significant (F(1, 30) = 4.152, p = 0.050). For female group, the simple main effect of treatment was significant (F(1, 11) = 8.040, p = 0.016), indicating that the mean change score was higher in the HT7 stimulation than in the LI5 stimulation. Therefore, our study has provided evidence to support that HT7 stimulation has a positive therapeutic effect on the alcohol-related diseases. PMID:28280514

  15. Implantation serine proteinase 2 is a monomeric enzyme with mixed serine proteolytic activity and can silence signalling via proteinase activated receptors.

    Science.gov (United States)

    Sharma, Navneet; Fahr, Jochen; Renaux, Bernard; Saifeddine, Mahmoud; Kumar, Rajeev; Nishikawa, Sandra; Mihara, Koichiro; Ramachandran, Rithwik; Hollenberg, Morley D; Rancourt, Derrick E

    2013-12-01

    Implantation serine proteinase 2 (ISP2), a S1 family serine proteinase, is known for its role in the critical processes of embryo hatching and implantation in the mouse uterus. Native implantation serine proteinases (ISPs) are co-expressed and co-exist as heterodimers in uterine and blastocyst tissues. The ISP1-ISP2 enzyme complex shows trypsin-like substrate specificity. In contrast, we found that ISP2, isolated as a 34 kDa monomer from a Pichia pastoris expression system, exhibited a mixed serine proteolytic substrate specificity, as determined by a phage display peptide cleavage approach and verified by the in vitro cleavage of synthetic peptides. Based upon the peptide sequence substrate selectivity, a database search identified many potential ISP2 targets of physiological relevance, including the proteinase activated receptor 2 (PAR2). The in vitro cleavage studies with PAR2-derived peptides confirmed the mixed substrate specificity of ISP2. Treatment of cell lines expressing proteinase-activated receptors (PARs) 1, 2, and 4 with ISP2 prevented receptor activation by either thrombin (PARs 1 and 4) or trypsin (PAR2). The disarming and silencing of PARs by ISP2 may play a role in successful embryo implantation.

  16. An fMRI study of nicotine-deprived smokers' reactivity to smoking cues during novel/exciting activity.

    Directory of Open Access Journals (Sweden)

    Xiaomeng Xu

    Full Text Available Engaging in novel/exciting ("self-expanding" activities activates the mesolimbic dopamine pathway, a brain reward pathway also associated with the rewarding effects of nicotine. This suggests that self-expanding activities can potentially substitute for the reward from nicotine. We tested this model among nicotine-deprived smokers who, during fMRI scanning, played a series of two-player cooperative games with a relationship partner. Games were randomized in a 2 (self-expanding vs. not x 2 (cigarette cue present vs. absent design. Self-expansion conditions yielded significantly greater activation in a reward region (caudate than did non-self-expansion conditions. Moreover, when exposed to smoking cues during the self-expanding versus the non-self-expanding cooperative games, smokers showed less activation in a cigarette cue-reactivity region, a priori defined [temporo-parietal junction (TPJ] from a recent meta-analysis of cue-reactivity. In smoking cue conditions, increases in excitement associated with the self-expanding condition (versus the non-self-expanding condition were also negatively correlated with TPJ activation. These results support the idea that a self-expanding activity promoting reward activation attenuates cigarette cue-reactivity among nicotine-deprived smokers. Future research could focus on the parameters of self-expanding activities that produce this effect, as well as test the utility of self-expansion in clinical interventions for smoking cessation.

  17. Simultaneous reconstruction of attenuation and activity in ToF PET/MRI with additional transmission data

    Energy Technology Data Exchange (ETDEWEB)

    D’Hoe, Ester [MEDISIP Medical Imaging and Signal Processing Group, Ghent University, IBBT-IBiTech, iMinds Medical IT, Ghent (Belgium); Department of Nuclear Medicine, Vrije Universiteit Brussel, Brussels (Belgium); Mollet, Pieter; Mikhaylova, Ekaterina [MEDISIP Medical Imaging and Signal Processing Group, Ghent University, IBBT-IBiTech, iMinds Medical IT, Ghent (Belgium); Defrise, Michel [Department of Nuclear Medicine, Vrije Universiteit Brussel, Brussels (Belgium); Vandenberghe, Stefaan [MEDISIP Medical Imaging and Signal Processing Group, Ghent University, IBBT-IBiTech, iMinds Medical IT, Ghent (Belgium)

    2015-05-18

    In Time-of-Flight PET/MRI systems accurate attenuation correction, based on the MRI image, is not straight forward. An alternative is attenuation correction based on emission data only. This is for instance done by simultaneous reconstruction of attenuation and activity with the MLAA algorithm, but the method as originally proposed has certain limits. The attenuation can only be determined up to a constant and in regions of low tracer uptake, the method results in less accurate attenuation values. An adapted MLAA algorithm has been proposed to overcome this issues and was successfully applied on simulation studies. The so called MLAA+ algorithm uses regular PET emission data as well as transmission data. This transmission data is acquired after insertion of an annulus shaped transmission source into the scanner bore. The Time-of-Flight information allows to separate transmission and emission data in a simultaneous acquisition. With the transmission data, an MLTR-based reference attenuation image is reconstructed. Afterwards, this attenuation image is used in the MLAA+ simultaneous reconstruction of attenuation and emission as a reference. We here propose the results of the reconstruction of patient data, based on the MLAA+ algorithm. In total, seven patients were scanned in a sequential PET/MRI scanner and afterwards in a CT scanner. The CT scan is used as an attenuation map to reconstruct the PET emission data with the well established MLEM algorithm. This reconstruction can be seen as the gold standard to which we can compare the MLAA and MLAA+ reconstructions. A preliminary study on one patient indicates that the MLAA+ algorithm results in better reconstructed emission and attenuation images as compared to the MLAA algorithm. If we compare the MLAA+ method to the gold standard, there is still room for improvement.

  18. [An fMRI study on brain activation patterns of males and females during video sexual stimulation].

    Science.gov (United States)

    Yang, Bo; Zhang, Jin-shan; Wang, Tao; Zhou, Yi-cheng; Liu, Ji-hong; Ma, Lin

    2007-08-01

    To investigate the difference in the brain activation patterns of males and females during video sexual stimulation by functional magnetic resonance imaging (fMRI). The participants were 20 adult males and 20 adult females, all healthy, right-handed, and with no history of sexual function disorder and physical, psychiatric or neurological diseases. Blood-oxygen-level-dependent fMRI was performed using a 1.5 T MR scanner. Three-dimensional anatomical image of the entire brain were obtained by using a T1-weighted three-dimensional anatomical image spoiled gradient echo pulse sequence. Each person was shown neutral and erotic video sequences for 60 s each in a block-study fashion, i.e. neutral scenes--erotic scenes--neutral scenes, and so on. The total scanning time was approximately 7 minutes, with a 12 s interval between two subsequent video sequences in order to avoid any overlapping between erotic and neutral information. The video sexual stimulation produced different results in the men and women. The females showed activation both in the left and the right amygdala, greater in the former than in the latter ([220.52 +/- 17.09] mm3 vs. [155.45 +/- 18.34] mm3, P < 0.05), but in the males only the left amygdala was activated. The males showed greater brain activation than the females in the left anterior cingulate gyrus ([420.75 +/- 19.37] mm3 vs. [310.67 +/- 10.53] mm3, P < 0.05), but less than the females in the splenium of the corpus callosum ([363.32 +/- 13.30] mm3 vs. [473.45 +/- 14.92] mm3, P < 0.01). Brain activation patterns of males and females during video sexual stimulation are different, underlying which is presumably the difference in both the structure and function of the brain between men and women.

  19. Initial experience with lung-MRI at 3.0 T: Comparison with CT and clinical data in the evaluation of interstitial lung disease activity

    Energy Technology Data Exchange (ETDEWEB)

    Lutterbey, G. [Department of Radiology, University of Bonn, Sigmund-Freud-Strasse 25, D-53105 Bonn (Germany)]. E-mail: goetz.lutterbey@ukb.uni-bonn.de; Grohe, C. [Department of Internal Medicine, University of Bonn (Germany); Gieseke, J. [PHILIPS Medical Systems, Best (Netherlands); Falkenhausen, M. von [Department of Radiology, University of Bonn, Sigmund-Freud-Strasse 25, D-53105 Bonn (Germany); Morakkabati, N. [Department of Radiology, University of Bonn, Sigmund-Freud-Strasse 25, D-53105 Bonn (Germany); Wattjes, M.P. [Department of Radiology, University of Bonn, Sigmund-Freud-Strasse 25, D-53105 Bonn (Germany); Manka, R. [Department of Internal Medicine, University of Bonn (Germany); Trog, D. [Department of Radiology, University of Bonn, Sigmund-Freud-Strasse 25, D-53105 Bonn (Germany); Schild, H.H. [Department of Radiology, University of Bonn, Sigmund-Freud-Strasse 25, D-53105 Bonn (Germany)

    2007-02-15

    Objectives: We evaluated the feasibility of highfield lung-MRI at 3.0 T. A comparison with Computed Tomography (CT) and clinical data regarding the assessment of inflammatory activity in patients with diffuse lung disease was performed. Material and methods: Prospective evaluation of 21 patients (15 males, 6 females, 43-80 y) with diffuse lung diseases who underwent clinical work-up inclusive laboratory tests, lung-function tests and transbronchial biopsy. After routine helical CT (additional 12 HRCT) a lung-MRI (3.0 Intera, Philips Medical Systems, Best, The Netherlands) using a T2-weighted, cardiac and respiratory triggered Fast-Spinecho-Sequence (TE/TR = 80/1500-2500 ms, 22 transverse slices, 7/2 mm slice-thickness/-gap) was performed. A pneumologist classified the cases into two groups: A = temporary acute interstitial disease or chronic interstitial lung disease with acute episode or superimposed infection/B = burned out interstitial lung disease without activity. Two blinded CT-radiologists graded the cases in active/inactive disease on the basis of nine morphological criteria each. A third radiologist rated the MRI-cases as active/inactive, depending on the signal-intensities of lung tissues. Results: The pneumologist classified 14 patients into group A and 7 patients into group B. Using CT, 6 cases were classified as active, 15 cases as inactive disease. With MRI 12 cases were classified as active and 9 cases as inactive. In the complete group of 21 patients MRI decisions and CT decisions respectively were false positive/false negative/correct in 2/4/15 respectively 0/8/13 cases. Correct diagnoses were obtained in 72% (MRI) respectively 62% (CT). In the subgroup of 12 cases including HRCT, MRI respectively CT were false positive/false negative/correct in 2/1/9 respectively 0/5/7 cases. Correct diagnoses were obtained in 75% (MRI) respectively 58% (CT). Conclusion: Highfield MRI of the lung is feasible and performed slightly better compared to CT in the

  20. Joint Coupling of Awake EEG Frequency Activity and MRI Gray Matter Volumes in the Psychosis Dimension: A BSNIP Study.

    Science.gov (United States)

    Soh, Pauline; Narayanan, Balaji; Khadka, Sabin; Calhoun, Vince D; Keshavan, Matcheri S; Tamminga, Carol A; Sweeney, John A; Clementz, Brett A; Pearlson, Godfrey D

    2015-01-01

    Many studies have examined either electroencephalogram (EEG) frequency activity or gray matter volumes (GMV) in various psychoses [including schizophrenia (SZ), schizoaffective (SZA), and psychotic bipolar disorder (PBP)]. Prior work demonstrated similar EEG and gray matter abnormalities in both SZ and PBP. Integrating EEG and GMV and jointly analyzing the combined data fully elucidates the linkage between the two and may provide better biomarker- or endophenotype-specificity for a particular illness. Joint exploratory investigations of EEG and GMV are scarce in the literature and the relationship between the two in psychosis is even less explored. We investigated a joint multivariate model to test whether the linear relationship or linkage between awake EEG (AEEG) frequency activity and GMV is abnormal across the psychosis dimension and if such effects are also present in first-degree relatives. We assessed 607 subjects comprising 264 probands [105 SZ, 72 SZA, and 87 PBP], 233 of their first degree relatives [82 SZ relatives (SZR), 71 SZA relatives (SZAR), and 80 PBP relatives (PBPR)], and 110 healthy comparison subjects (HC). All subjects underwent structural MRI (sMRI) and EEG scans. Frequency activity and voxel-based morphometric GMV were derived from EEG and sMRI data, respectively. Seven AEEG frequency and gray matter components were extracted using Joint independent component analysis (jICA). The loading coefficients (LC) were examined for group differences using analysis of covariance. Further, the LCs were correlated with psychopathology scores to identify relationship with clinical symptoms. Joint ICA revealed a single component differentiating SZ from HC (p < 0.006), comprising increased posterior alpha activity associated with decreased volume in inferior parietal lobe, supramarginal, parahippocampal gyrus, middle frontal, inferior temporal gyri, and increased volume of uncus and culmen. No components were aberrant in either PBP or SZA or any

  1. Joint Coupling of Awake EEG Frequency Activity and MRI Gray Matter Volumes in the Psychosis Dimension; A BSNIP Study

    Directory of Open Access Journals (Sweden)

    Pauline eSoh

    2015-11-01

    Full Text Available Many studies have examined either electroencephalogram (EEG frequency activity or gray matter volumes (GMV in various psychoses (including schizophrenia, schizoaffective and psychotic bipolar disorder. Prior work demonstrated similar EEG and gray matter abnormalities in both schizophrenia and psychotic bipolar disorder. Integrating EEG and GMV and jointly analyzing the combined data fully elucidates the linkage between the two and may provide better biomarker- or endophenotype-specificity for a particular illness. Joint exploratory investigations of EEG and GMV are scarce in the literature and the relationship between the two in psychosis is even less explored. We investigated a joint multivariate model to test whether the linear relationship or linkage between awake EEG (AEEG frequency activity and GMV is abnormal across the psychosis dimension and if such effects are also present in first-degree relatives.We assessed 607 subjects comprising 264 probands (105 schizophrenia (SZ, 72 schizoaffective (SZA and 87 psychotic bipolar disorder (PBP, 233 of their first degree relatives (82 SZ relatives (SZR, 71 SZA relatives (SZAR and 80 PBP relatives (PBPR and 110 healthy comparison subjects (HC. All subjects underwent structural MRI (sMRI and EEG scans. Frequency activity and voxel based morphometric GMV were derived from EEG and sMRI data respectively. Seven AEEG frequency and gray matter components were extracted using Joint independent component analysis (jICA. The loading coefficients (LC were examined for group differences using analysis of covariance. Further, the LCs were correlated with psychopathology scores to identify relationship with clinical symptoms. Joint ICA revealed a single component differentiating SZ from HC (p<0.006, comprising increased posterior alpha activity associated with decreased volume in inferior parietal lobe, supra-marginal, parahippocampal gyrus, middle frontal, inferior temporal gyri and increased volume of uncus and

  2. Evaluating the Safety Profile of Non-Active Implantable Medical Devices Compared with Medicines.

    Science.gov (United States)

    Pane, Josep; Coloma, Preciosa M; Verhamme, Katia M C; Sturkenboom, Miriam C J M; Rebollo, Irene

    2017-01-01

    Recent safety issues involving non-active implantable medical devices (NAIMDs) have highlighted the need for better pre-market and post-market evaluation. Some stakeholders have argued that certain features of medicine safety evaluation should also be applied to medical devices. Our objectives were to compare the current processes and methodologies for the assessment of NAIMD safety profiles with those for medicines, identify potential gaps, and make recommendations for the adoption of new methodologies for the ongoing benefit-risk monitoring of these devices throughout their entire life cycle. A literature review served to examine the current tools for the safety evaluation of NAIMDs and those for medicines. We searched MEDLINE using these two categories. We supplemented this search with Google searches using the same key terms used in the MEDLINE search. Using a comparative approach, we summarized the new product design, development cycle (preclinical and clinical phases), and post-market phases for NAIMDs and drugs. We also evaluated and compared the respective processes to integrate and assess safety data during the life cycle of the products, including signal detection, signal management, and subsequent potential regulatory actions. The search identified a gap in NAIMD safety signal generation: no global program exists that collects and analyzes adverse events and product quality issues. Data sources in real-world settings, such as electronic health records, need to be effectively identified and explored as additional sources of safety information, particularly in some areas such as the EU and USA where there are plans to implement the unique device identifier (UDI). The UDI and other initiatives will enable more robust follow-up and assessment of long-term patient outcomes. The safety evaluation system for NAIMDs differs in many ways from those for drugs, but both systems face analogous challenges with respect to monitoring real-world usage. Certain features

  3. Effect of Left Ventricular Assist Device Implantation and Heart Transplantation on Habitual Physical Activity and Quality of Life☆

    Science.gov (United States)

    Jakovljevic, Djordje G.; McDiarmid, Adam; Hallsworth, Kate; Seferovic, Petar M.; Ninkovic, Vladan M.; Parry, Gareth; Schueler, Stephan; Trenell, Michael I.; MacGowan, Guy A.

    2014-01-01

    The present study defined the short- and long-term effects of left ventricular assist device (LVAD) implantation and heart transplantation (HT) on physical activity and quality of life (QoL). Forty patients (LVAD, n = 14; HT, n = 12; and heart failure [HF], n = 14) and 14 matched healthy subjects were assessed for physical activity, energy expenditure, and QoL. The LVAD and HT groups were assessed postoperatively at 4 to 6 weeks (baseline) and 3, 6, and 12 months. At baseline, LVAD, HT, and HF patients demonstrated low physical activity, reaching only 15%, 28%, and 51% of that of healthy subjects (1,603 ± 302 vs 3,036 ± 439 vs 5,490 ± 1,058 vs 10,756 ± 568 steps/day, respectively, p <0.01). This was associated with reduced energy expenditure and increased sedentary time (p <0.01). Baseline QoL was not different among LVAD, HT, and HF groups (p = 0.44). LVAD implantation and HT significantly increased daily physical activity by 60% and 52%, respectively, from baseline to 3 months (p <0.05), but the level of activity remained unchanged at 3, 6, and 12 months. The QoL improved from baseline to 3 months in LVAD implantation and HT groups (p <0.01) but remained unchanged afterward. At any time point, HT demonstrated higher activity level than LVAD implantation (p <0.05), and this was associated with better QoL. In contrast, physical activity and QoL decreased at 12 months in patients with HF (p <0.05). In conclusion, patients in LVAD and HT patients demonstrate improved physical activity and QoL within the first 3 months after surgery, but physical activity and QoL remain unchanged afterward and well below that of healthy subjects. Strategies targeting low levels of physical activity should now be explored to improve recovery of these patients. PMID:24925802

  4. Local activation of uterine Toll-like receptor 2 and 2/6 decreases embryo implantation and affects uterine receptivity in mice.

    Science.gov (United States)

    Sanchez-Lopez, Javier Arturo; Caballero, Ignacio; Montazeri, Mehrnaz; Maslehat, Nasim; Elliott, Sarah; Fernandez-Gonzalez, Raul; Calle, Alexandra; Gutierrez-Adan, Alfonso; Fazeli, Alireza

    2014-04-01

    Embryo implantation is a complex interaction between maternal endometrium and embryonic structures. Failure to implant is highly recurrent and impossible to diagnose. Inflammation and infections in the female reproductive tract are common causes of infertility, embryo loss, and preterm labor. The current work describes how the activation of endometrial Toll-like receptor (TLR) 2 and 2/6 reduces embryo implantation chances. We developed a morphometric index to evaluate the effects of the TLR 2/6 activation along the uterine horn (UH). TLR 2/6 ligation reduced the endometrial myometrial and glandular indexes and increased the luminal index. Furthermore, TLR 2/6 activation increased the proinflammatory cytokines such as interleukin (IL)-1beta and monocyte chemotactic protein (MCP)-1 in UH lavages in the preimplantation day and IL-1 receptor antagonist in the implantation day. The engagement of TLR 2/6 with its ligand in the UH during embryo transfer severely affected the rate of embryonic implantation (45.00% ± 6.49% vs. 16.69% ± 5.01%, P embryo implantation process was verified using an in vitro model of human embryo implantation where trophoblast spheroids failed to adhere to a monolayer of TLR 2- and TLR 2/6-activated endometrial cells. The inhibition of TLR receptors 2 and 6 in the presence of their specific ligands restored the ability of the spheroids to bind to the endometrial cells. In conclusion, the activation of the innate immune system in the uterus at the time of implantation interfered with the endometrial receptivity and reduced the chances of implantation success.

  5. A fully Bayesian approach to the parcel-based detection-estimation of brain activity in fMRI

    Energy Technology Data Exchange (ETDEWEB)

    Makni, S. [Univ Oxford, John Radcliffe Hosp, Oxford Ctr Funct Magnet Resonance Imaging Brain, Oxford OX3 9DU (United Kingdom); Idier, J. [IRCCyN CNRS, Nantes (France); Vincent, T.; Ciuciu, P. [CEA, NeuroSpin, Gif Sur Yvette (France); Vincent, T.; Dehaene-Lambertz, G.; Ciuciu, P. [Inst Imagerie Neurofonctionnelle, IFR 49, Paris (France); Thirion, B. [INRIA Futurs, Orsay (France); Dehaene-Lambertz, G. [INSERM, NeuroSpin, U562, Gif Sur Yvette (France)

    2008-07-01

    Within-subject analysis in fMRI essentially addresses two problems, i. e., the detection of activated brain regions in response to an experimental task and the estimation of the underlying dynamics, also known as the characterisation of Hemodynamic response function (HRF). So far, both issues have been treated sequentially while it is known that the HRF model has a dramatic impact on the localisation of activations and that the HRF shape may vary from one region to another. In this paper, we conciliate both issues in a region-based joint detection-estimation framework that we develop in the Bayesian formalism. Instead of considering function basis to account for spatial variability, spatially adaptive General Linear Models are built upon region-based non-parametric estimation of brain dynamics. Regions are first identified as functionally homogeneous parcels in the mask of the grey matter using a specific procedure [Thirion, B., Flandin, G., Pinel, P., Roche, A., Ciuciu, P., Poline, J.B., August 2006. Dealing with the shortcomings of spatial normalization: Multi-subject parcellation of fMRI datasets. Hum. Brain Mapp. 27 (8), 678-693.]. Then, in each parcel, prior information is embedded to constrain this estimation. Detection is achieved by modelling activating, deactivating and non-activating voxels through mixture models within each parcel. From the posterior distribution, we infer upon the model parameters using Markov Chain Monte Carlo (MCMC) techniques. Bayesian model comparison allows us to emphasize on artificial datasets first that inhomogeneous gamma-Gaussian mixture models outperform Gaussian mixtures in terms of sensitivity/specificity trade-off and second that it is worthwhile modelling serial correlation through an AR(1) noise process at low signal-to-noise (SNR) ratio. Our approach is then validated on an fMRI experiment that studies habituation to auditory sentence repetition. This phenomenon is clearly recovered as well as the hierarchical temporal

  6. Dental Implants.

    Science.gov (United States)

    Griggs, Jason A

    2017-10-01

    Systematic reviews of literature over the period between 2008 and 2017 are discussed regarding clinical evidence for the factors affecting survival and failure of dental implants. The factors addressed include publication bias, tooth location, insertion torque, collar design, implant-abutment connection design, implant length, implant width, bone augmentation, platform switching, surface roughness, implant coatings, and the use of ceramic materials in the implant body and abutment. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Biological Activation of Inert Ceramics: Recent Advances Using Tailored Self-Assembled Monolayers on Implant Ceramic Surfaces

    Directory of Open Access Journals (Sweden)

    Frederik Böke

    2014-06-01

    Full Text Available High-strength ceramics as materials for medical implants have a long, research-intensive history. Yet, especially on applications where the ceramic components are in direct contact with the surrounding tissue, an unresolved issue is its inherent property of biological inertness. To combat this, several strategies have been investigated over the last couple of years. One promising approach investigates the technique of Self-Assembled Monolayers (SAM and subsequent chemical functionalization to create a biologically active tissue-facing surface layer. Implementation of this would have a beneficial impact on several fields in modern implant medicine such as hip and knee arthroplasty, dental applications and related fields. This review aims to give a summarizing overview of the latest advances in this recently emerging field, along with thorough introductions of the underlying mechanism of SAMs and surface cell attachment mechanics on the cell side.

  8. Changes in brain activation in stroke patients after mental practice and physical exercise:a functional MRI study

    Institute of Scientific and Technical Information of China (English)

    Hua Liu; Luping Song; Tong Zhang

    2014-01-01

    Mental practice is a new rehabilitation method that refers to the mental rehearsal of motor imagery content with the goal of improving motor performance. However, the relationship between activated regions and motor recovery after mental practice training is not well understood. In this study, 15 patients who suffered a first-ever subcortical stroke with neurological deficits affecting the right hand, but no significant cognitive impairment were recruited. 10 patients underwent mental practice combined with physical practice training, and 5 patients only underwent physical practice training. We observed brain activation regions after 4 weeks of training, and explored the correlation of activation changes with functional recovery of the affected hands. The results showed that, after 4 weeks of mental practice combined with physical training, the Fugl-Meyer assessment score for the affected right hand was significantly increased than that after 4 weeks of practice training alone. Functional MRI showed enhanced activation in the left primary somatosensory cortex, attenuated activation intensity in the right primary motor cortex, and enhanced right cerebellar activation observed during the motor imagery task using the affected right hand after mental practice training. The changes in brain cortical activity were related to functional recovery of the hand. Experimental findings indicate that cortical and cerebellar functional reorganization following mental practice contributed to the improvement of hand function.

  9. MRI of the Chest

    Medline Plus

    Full Text Available ... any questions. Some implanted devices require a short period of time after placement (usually six weeks) before ... If you do not require sedation, no recovery period is necessary. You may resume your usual activities ...

  10. Recent seizure activity alters motor organization in frontal lobe epilepsy as revealed by task-based fMRI.

    Science.gov (United States)

    Woodward, Kristine E; Gaxiola-Valdez, Ismael; Mainprize, David; Grossi, Matthew; Goodyear, Bradley G; Federico, Paolo

    2014-10-01

    Patients with frontal lobe epilepsy (FLE) commonly demonstrate motor impairments, suggesting that frontal lobe seizures affect motor function. However, the underlying mechanisms of these deficits are not known, nor has any study systematically examined motor organization in these patients. We therefore examined cortical motor organization in a group of adult patients with FLE, using task-based fMRI. Eleven right FLE patients, six left FLE patients, and ten control subjects underwent task-based fMRI. Two tasks were performed using the right and left hands separately, and both hands together. The first task was a finger-tapping task and the second task was a more complex coordination task. Functional MR data were compared between patient groups and controls. A laterality index of brain activation was also calculated between the epileptic and healthy hemisphere to determine hemispheric dominance during task performance to explore its relationship with a variety of patient-specific epilepsy factors. Overall, right FLE patients demonstrated decreased BOLD activity in the epileptic hemisphere and increased BOLD activity in the healthy hemisphere compared to controls (pseizure in both patient groups (right FLE: rs=0.779, left FLE: rs=0.943). Patients that had experienced a recent seizure relied more on the sensorimotor cortex of the healthy hemisphere during task performance, compared to those that were relatively seizure free (pseizure freedom. These results demonstrate the presence of seizure-related alteration of cortical motor organization in FLE, which may underlie the motor deficits seen in these patients. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. P1-27: Localizing Regions Activated by Surface Gloss in Macaque Visual Cortex by fMRI

    Directory of Open Access Journals (Sweden)

    Gouki Okazawa

    2012-10-01

    Full Text Available Surface properties of objects such as gloss provide important information about the states or materials of objects in our visual experiences. Previous studies have shown that there are cortical regions responding to shapes, colors, faces etc. in the macaque visual cortex. However, we still lack the information about where the surface properties are processed in the macaque visual cortex. In this study, we examined whether there are regions activated by surface gloss, an important surface property, in the macaque visual cortex by using functional magnetic resonance imaging (fMRI. We trained two monkeys to fixate on a small spot on the screen in MRI scanner, while the images of glossy and matte objects were presented. As a control condition for low-level image features, such as spatial frequency or luminance contrast, we generated scrambled images by locally randomizing the luminance phases of images using wavelet filters. By contrasting the responses to glossy images to those to matte and scrambled images, we found the activation in wide regions along the ventral visual pathway including V1, V2, V3, V4, and the posterior part of the inferior temporal (IT cortex. In one monkey, we also found the activations in the central part of IT cortex. In another control experiment, we manipulated the image contrasts and found that the responses in these regions cannot be explained simply by the image contrasts. These results suggest that surface gloss is processed along the ventral pathway and, in the IT cortex there are distinct regions processing surface gloss.

  12. Correlations between brain activity and components of motor learning in middle-aged adults: An fMRI study

    Directory of Open Access Journals (Sweden)

    Katie P Wadden

    2013-05-01

    Full Text Available Implicit learning may be shown by improvements in motor performance, which occur unconsciously with practice and are typically restricted to the task that was practiced. The purpose of this study was to examine behaviorally relevant brain activation associated with change in motor behaviour during sequence-specific motor learning of a perceptuomotor continuous tracking (CT task in middle-aged adults. To gain further insight into the neural structures associated with change in motor behaviour, overall improvement in tracking (root mean square error; RMSE was decomposed into two components – temporal precision and spatial accuracy. A group of middle-aged healthy individuals performed the CT task, which contains repeated and random segments for seven days. Functional magnetic resonance imaging (fMRI data was collected on the first and seventh day while the participants performed the task. To assess behaviorally relevant changes in the blood oxygenation level dependent (BOLD response associated with individual sequence-specific tracking performance, separate statistical images were created for each participant and weighted by the difference score between repeated and random performance for days 1 and 7. On Day 7 the resultant group statistical fMRI image demonstrated a positive correlation between RMSE difference score and bilateral cerebellar activation (lobule VI. In addition, individuals who showed greater sequence-specific temporal precision demonstrated increased activation in the precentral gyrus, middle occipital gyrus and putamen of the right hemisphere and the thalamus, cuneus and cerebellum of the left hemisphere. In the present study, behavioral performance was associated with neural correlates of individual variation in motor learning that characterized the ability to implicitly learn a sequence-specific CT task.

  13. Long-term vascular access ports as a means of sedative administration in a rodent fMRI survival model.

    Science.gov (United States)

    Hettinger, Patrick C; Li, Rupeng; Yan, Ji-Geng; Matloub, Hani S; Cho, Younghoon R; Pawela, Christopher P; Rowe, Daniel B; Hyde, James S

    2011-09-15

    The purpose of this study is to develop a rodent functional magnetic resonance imaging (fMRI) survival model with the use of heparin-coated vascular access devices. Such a model would ease the administration of sedative agents, reduce the number of animals required in survival experiments and eliminate animal-to-animal variability seen in previous designs. Seven male Sprague-Dawley rats underwent surgical placement of an MRI-compatible vascular access port, followed by implantable electrode placement on the right median nerve. Functional MRI during nerve stimulation and resting-state functional connectivity MRI (fcMRI) were performed at times 0, 2, 4, 8 and 12 weeks postoperatively using a 9.4T scanner. Anesthesia was maintained using intravenous dexmedetomidine and reversed using atipamezole. There were no fatalities or infectious complications during this study. All vascular access ports remained patent. Blood oxygen level dependent (BOLD) activation by electrical stimulation of the median nerve using implanted electrodes was seen within the forelimb sensory region (S1FL) for all animals at all time points. The number of activated voxels decreased at time points 4 and 8 weeks, returning to a normal level at 12 weeks, which is attributed to scar tissue formation and resolution around the embedded electrode. The applications of this experiment extend far beyond the scope of peripheral nerve experimentation. These vascular access ports can be applied to any survival MRI study requiring repeated medication administration, intravenous contrast, or blood sampling.

  14. fMRI investigation of the effect of local and systemic lidocaine on noxious electrical stimulation-induced activation in spinal cord.

    Science.gov (United States)

    Zhao, Fuqiang; Williams, Mangay; Welsh, Denise C; Meng, Xiangjun; Ritter, Amy; Abbadie, Catherine; Cook, Jacquelynn J; Reicin, Alise S; Hargreaves, Richard; Williams, Donald S

    2009-09-01

    Spinal cord fMRI offers an excellent opportunity to quantify nociception using neuronal activation induced by painful stimuli. Measurement of the magnitude of stimulation-induced activation, and its suppression with analgesics can provide objective measures of pain and efficacy of analgesics. This study investigates the feasibility of using spinal cord fMRI in anesthetized rats as a pain assay to test the analgesic effect of locally and systemically administered lidocaine. Blood volume (BV)-weighted fMRI signal acquired after intravenous injection of ultrasmall superparamagnetic iron oxide (USPIO) particles was used as an indirect readout of the neuronal activity. Transcutaneous noxious electrical stimulation was used as the pain model. BV-weighted fMRI signal could be robustly quantified on a run-by-run basis, opening the possibility of measuring pharmacodynamics (PD) of the analgesics with a temporal resolution of approximately 2 min. Local administration of lidocaine was shown to ablate all stimulation-induced fMRI signals by the total blockage of peripheral nerve transmission, while the analgesic effect of systemically administered lidocaine was robustly detected after intravenous infusion of approximately 3mg/kg, which is similar to clinical dosage for human. This study establishes spinal cord fMRI as a viable assay for analgesics. With respect to the mode of action of lidocaine, this study suggests that systemic lidocaine, which is clinically used for the treatment of neuropathic pain, and believed to only block the peripheral nerve transmission of abnormal neural activity (ectopic discharge) originating from the damaged peripheral nerves, also blocks the peripheral nerve transmission of normal neural activity induced by transcutaneous noxious electrical stimulation.

  15. Changes in fMRI activation in anterior hippocampus and motor cortex during memory retrieval after an intense exercise intervention.

    Science.gov (United States)

    Wagner, Gerd; Herbsleb, Marco; de la Cruz, Feliberto; Schumann, Andy; Köhler, Stefanie; Puta, Christian; Gabriel, Holger W; Reichenbach, Jürgen R; Bär, Karl-Jürgen

    2017-03-01

    Strong evidence indicates that regular aerobic training induces beneficial effects on cognitive functions. The present controlled fMRI study was designed to investigate the impact of a short-term intense aerobic exercise on the pattern of functional activation during the retrieval of learned pair-associates in 17 young and healthy male adults compared to 17 matched control subjects. We further aimed to relate putative changes in hippocampal activation to postulated changes in the exercised-induced brain derived neurotrophic factor (BDNF). The supervised exercise program was performed on a bicycle ergometer and lasted six weeks, with three aerobic sessions per week. We found profound improvement of physical fitness in most subjects indicated by the target parameter 'individual anaerobic threshold'. Significant improvements in the cognitive performance were detected in the exercise group, but also in the control group. We observed significant differences in the activation pattern of the left anterior hippocampus during the pair-associates task after the intervention. We could also show a significant positive correlation between changes in exercise-induced BDNF and left anterior hippocampal activation. Moreover, we observed the brain's motor network to be significantly stronger activated after the exercise intervention. Thus, our results suggest BDNF dependent activation changes of the hippocampus in addition to previously described structural changes after exercise. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Relation between functional magnetic resonance imaging (fMRI and single neuron, local field potential (LFP and electrocorticography (ECoG activity in human cortex

    Directory of Open Access Journals (Sweden)

    George A. Ojemann

    2013-02-01

    Full Text Available The relation between changes in the blood oxygen dependent metabolic changes imaged by fMRI and neural events directly recorded from human cortex from single neurons, LFPs and ECoG is critically reviewed, based on the published literature including findings from the authors’ laboratories. All these data are from special populations, usually patients with medically refractory epilepsy, as this provides the major opportunity for direct cortical neuronal recording in humans. For LFP and ECoG changes are often sought in different frequency bands, for single neurons in frequency of action potentials. Most fMRI studies address issues of functional localization. The relation of those findings to localized changes in neuronal recordings in humans has been established in several ways. Only a few studies have directly compared changes in activity from the same sites in the same individual, using the same behavioral measure. More often the comparison has been between fMRI and electrophysiologic changes in populations recorded from the same functional anatomic system as defined by lesion effects; in a few studies those systems have been defined by fMRI changes such as the default network. The fMRI-electrophysiologic relationships have been evaluated empirically by colocalization of significant changes, and by quantitative analyses, often multiple linear regression. There is some evidence that the fMRI-electrophysiology relationships differ in different cortical areas, particularly primary motor and sensory cortices compared to association cortex, but also within areas of association cortex. Although crucial for interpretation of fMRI changes as reflecting neural activity in human cortex, controversy remains as to these relationships.Supported by: Dutch Technology Foundation and University of Utrecht Grant UGT7685, ERC-Advanced grant 320708 (NR and NIH grant NS065186 (JO

  17. Relation between functional magnetic resonance imaging (fMRI) and single neuron, local field potential (LFP) and electrocorticography (ECoG) activity in human cortex.

    Science.gov (United States)

    Ojemann, George A; Ojemann, Jeffrey; Ramsey, Nick F

    2013-01-01

    The relation between changes in the blood oxygen dependent metabolic changes imaged by functional magnetic resonance imaging (fMRI) and neural events directly recorded from human cortex from single neurons, local field potentials (LFPs) and electrocorticogram (ECoG) is critically reviewed, based on the published literature including findings from the authors' laboratories. All these data are from special populations, usually patients with medically refractory epilepsy, as this provides the major opportunity for direct cortical neuronal recording in humans. For LFP and ECoG changes are often sought in different frequency bands, for single neurons in frequency of action potentials. Most fMRI studies address issues of functional localization. The relation of those findings to localized changes in neuronal recordings in humans has been established in several ways. Only a few studies have directly compared changes in activity from the same sites in the same individual, using the same behavioral measure. More often the comparison has been between fMRI and electrophysiologic changes in populations recorded from the same functional anatomic system as defined by lesion effects; in a few studies those systems have been defined by fMRI changes such as the "default" network. The fMRI-electrophysiologic relationships have been evaluated empirically by colocalization of significant changes, and by quantitative analyses, often multiple linear regression. There is some evidence that the fMRI-electrophysiology relationships differ in different cortical areas, particularly primary motor and sensory cortices compared to association cortex, but also within areas of association cortex. Although crucial for interpretation of fMRI changes as reflecting neural activity in human cortex, controversy remains as to these relationships. Supported by: Dutch Technology Foundation and University of Utrecht Grant UGT7685, ERC-Advanced grant 320708 (NR) and NIH grant NS065186 (JO).

  18. Prevalence of inner ear anomalies among cochlear implant candidates

    OpenAIRE

    Aldhafeeri, Ahmad M.; Alsanosi, Abdulrahman A.

    2016-01-01

    Objectives: To determine the prevalence of inner ear anomalies and the frequency of different anomaly types among cochlear implant recipients. Methods: This study included a retrospective chart review of all patients who received cochlear implants between January 2009 and January 2013 in King Abdulaziz University Hospital cochlear implant program in Riyadh, Saudi Arabia. All subjects underwent thin-cut CT of the temporal bone and MRI. The collected data included age, gender, and CT and MRI fi...

  19. The activL® Artificial Disc: a next-generation motion-preserving implant for chronic lumbar discogenic pain

    Directory of Open Access Journals (Sweden)

    Yue JJ

    2016-05-01

    Full Text Available James J Yue,1 Rolando Garcia Jr,2 Larry E Miller3 1Department of Orthopaedic Surgery, Yale School of Medicine, New Haven, CT, 2Orthopedic Care Center, Miami, FL, 3Miller Scientific Consulting, Inc., Asheville, NC, USA Abstract: Degeneration of the lumbar intervertebral discs is a leading cause of chronic low back pain in adults. Treatment options for patients with chronic lumbar discogenic pain unresponsive to conservative management include total disc replacement (TDR or lumbar fusion. Until recently, only two lumbar TDRs had been approved by the US Food and Drug Administration - the Charité Artificial Disc in 2004 and the ProDisc-L Total Disc Replacement in 2006. In June 2015, a next-generation lumbar TDR received Food and Drug Administration approval - the activL® Artificial Disc (Aesculap Implant Systems. Compared to previous-generation lumbar TDRs, the activL® Artificial Disc incorporates specific design enhancements that result in a more precise anatomical match and allow a range of motion that better mimics the healthy spine. The results of mechanical and clinical studies demonstrate that the activL® Artificial Disc results in improved mechanical and clinical outcomes versus earlier-generation artificial discs and compares favorably to lumbar fusion. The purpose of this report is to describe the activL® Artificial Disc including implant characteristics, intended use, surgical technique, postoperative care, mechanical testing, and clinical experience to date. Keywords: activL® Artificial Disc, artificial disc, degenerative disc disease, discogenic, implant, lumbar, motion preservation, pain

  20. Application of active middle ear implants in patients with severe mixed hearing loss.

    NARCIS (Netherlands)

    Verhaegen, V.J.O.; Mulder, J.J.S.; Cremers, C.W.R.J.; Snik, A.F.M.

    2012-01-01

    OBJECTIVE: To determine the long-term benefit of the Vibrant Soundbridge (VSB) middle ear implant in patients with severe mixed hearing loss and to compare it with other hearing devices. DESIGN: A retrospective analysis. SETTING: University-affiliated medical center. PATIENTS: Six patients with seve

  1. Electrical Activation Studies of Silicon Implanted Aluminum Gallium Nitride with High Aluminum Mole Fraction

    Science.gov (United States)

    2007-12-01

    important to minimize imperfections and defects as well as the amount of unwanted impurities. The most common bulk method is the Czochralski Method , in...demonstrates a method for producing highly conductive Si- implanted n-type aluminum gallium nitride (AlxGa1-xN) alloys, and represents a comprehensive...54 IV. Experimental Method ..................................................................................... 57 Sample

  2. Real-time neurofeedback using functional MRI could improve down-regulation of amygdala activity during emotional stimulation: a proof-of-concept study.

    Science.gov (United States)

    Brühl, Annette Beatrix; Scherpiet, Sigrid; Sulzer, James; Stämpfli, Philipp; Seifritz, Erich; Herwig, Uwe

    2014-01-01

    The amygdala is a central target of emotion regulation. It is overactive and dysregulated in affective and anxiety disorders and amygdala activity normalizes with successful therapy of the symptoms. However, a considerable percentage of patients do not reach remission within acceptable duration of treatment. The amygdala could therefore represent a promising target for real-time functional magnetic resonance imaging (rtfMRI) neurofeedback. rtfMRI neurofeedback directly improves the voluntary regulation of localized brain activity. At present, most rtfMRI neurofeedback studies have trained participants to increase activity of a target, i.e. up-regulation. However, in the case of the amygdala, down-regulation is supposedly more clinically relevant. Therefore, we developed a task that trained participants to down-regulate activity of the right amygdala while being confronted with amygdala stimulation, i.e. negative emotional faces. The activity in the functionally-defined region was used as online visual feedback in six healthy subjects instructed to minimize this signal using reality checking as emotion regulation strategy. Over a period of four training sessions, participants significantly increased down-regulation of the right amygdala compared to a passive viewing condition to control for habilitation effects. This result supports the concept of using rtfMRI neurofeedback training to control brain activity during relevant stimulation, specifically in the case of emotion, and has implications towards clinical treatment of emotional disorders.

  3. MRI texture analysis (MRTA) of T2-weighted images in Crohn's disease may provide information on histological and MRI disease activity in patients undergoing ileal resection

    Energy Technology Data Exchange (ETDEWEB)

    Makanyanga, Jesica; Bhatnagar, Gauraang; Halligan, Steve; Taylor, Stuart A. [University College London and University College London Hospitals NIHR Biomedical Research Centre, Center for Medical Imaging, London (United Kingdom); Ganeshan, Balaji; Groves, Ashley; Miles, Ken [University College London, University College Hospital, Institute of Nuclear Medicine, London (United Kingdom); Rodriguez-Justo, Manuel [University College London, Department of Research Pathology, University College London Cancer Institute, London (United Kingdom)

    2017-02-15

    To associate MRI textural analysis (MRTA) with MRI and histological Crohn's disease (CD) activity. Sixteen patients (mean age 39.5 years, 9 male) undergoing MR enterography before ileal resection were retrospectively analysed. Thirty-six small (≤3 mm) ROIs were placed on T2-weighted images and location-matched histological acute inflammatory scores (AIS) measured. MRI activity (mural thickness, T2 signal, T1 enhancement) (CDA) was scored in large ROIs. MRTA features (mean, standard deviation, mean of positive pixels (MPP), entropy, kurtosis, skewness) were extracted using a filtration histogram technique. Spatial scale filtration (SSF) ranged from 2 to 5 mm. Regression (linear/logistic) tested associations between MRTA and AIS (small ROIs), and CDA/constituent parameters (large ROIs). Skewness (SSF = 2 mm) was associated with AIS [regression coefficient (rc) 4.27, p = 0.02]. Of 120 large ROI analyses (for each MRI, MRTA feature and SSF), 15 were significant. Entropy (SSF = 2, 3 mm) and kurtosis (SSF = 3 mm) were associated with CDA (rc 0.9, 1.0, -0.45, p = 0.006-0.01). Entropy and mean (SSF = 2-4 mm) were associated with T2 signal [odds ratio (OR) 2.32-3.16, p = 0.02-0.004], [OR 1.22-1.28, p = 0.03-0.04]. MPP (SSF = 2 mm) was associated with mural thickness (OR 0.91, p = 0.04). Kurtosis (SSF = 3 mm), standard deviation (SSF = 5 mm) were associated with decreased T1 enhancement (OR 0.59, 0.42, p = 0.004, 0.007). MRTA features may be associated with CD activity. (orig.)

  4. Decoding of visual information from human brain activity: A review of fMRI and EEG studies.

    Science.gov (United States)

    Zafar, Raheel; Malik, Aamir Saeed; Kamel, Nidal; Dass, Sarat C; Abdullah, Jafri M; Reza, Faruque; Abdul Karim, Ahmad Helmy

    2015-06-01

    Brain is the command center for the body and contains a lot of information which can be extracted by using different non-invasive techniques. Electroencephalography (EEG), Magnetoencephalography (MEG) and functional magnetic resonance imaging (fMRI) are the most common neuroimaging techniques to elicit brain behavior. By using these techniques different activity patterns can be measured within the brain to decode the content of mental processes especially the visual and auditory content. This paper discusses the models and imaging techniques used in visual decoding to investigate the different conditions of brain along with recent advancements in brain decoding. This paper concludes that it's not possible to extract all the information from the brain, however careful experimentation, interpretation and powerful statistical tools can be used with the neuroimaging techniques for better results.

  5. Neural Response during the Activation of the Attachment System in Patients with Borderline Personality Disorder: An fMRI Study.

    Science.gov (United States)

    Buchheim, Anna; Erk, Susanne; George, Carol; Kächele, Horst; Martius, Philipp; Pokorny, Dan; Spitzer, Manfred; Walter, Henrik

    2016-01-01

    Individuals with borderline personality disorder (BPD) are characterized by emotional instability, impaired emotion regulation and unresolved attachment patterns associated with abusive childhood experiences. We investigated the neural response during the activation of the attachment system in BPD patients compared to healthy controls using functional magnetic resonance imaging (fMRI). Eleven female patients with BPD without posttraumatic stress disorder (PTSD) and 17 healthy female controls matched for age and education were telling stories in the scanner in response to the Adult Attachment Projective Picture System (AAP), an eight-picture set assessment of adult attachment. The picture set includes theoretically-derived attachment scenes, such as separation, death, threat and potential abuse. The picture presentation order is designed to gradually increase the activation of the attachment system. Each picture stimulus was presented for 2 min. Analyses examine group differences in attachment classifications and neural activation patterns over the course of the task. Unresolved attachment was associated with increasing amygdala activation over the course of the attachment task in patients as well as controls. Unresolved controls, but not patients, showed activation in the right dorsolateral prefrontal cortex (DLPFC) and the rostral cingulate zone (RCZ). We interpret this as a neural signature of BPD patients' inability to exert top-down control under conditions of attachment distress. These findings point to possible neural mechanisms for underlying affective dysregulation in BPD in the context of attachment trauma and fear.

  6. Cortical activation by tactile stimulation to face and anterior neck areas: an fMRI study with three analytic methods.

    Science.gov (United States)

    Lin, Chou-Ching K; Sun, Yung-Nien; Huang, Chung-I; Yu, Chin-Yin; Ju, Ming-Shaung

    2010-12-01

    The main purpose of this study was to investigate the sensory cortical activation of the anterior neck region and the relationship between the neck and face representation areas. Functional MRI by blood oxygenation level dependent measurements was performed while tactile stimulation was applied to the face or neck area. Nonpainful tactile stimuli were manually delivered by an experimenter at a frequency of ∼1 Hz. Block (epoch) design was adopted with a block duration of 30 s and a whole run duration of 6 min. For each location, two runs were performed. After the image data were preprocessed, both parameteric and nonparametric methods were performed to test the group results. The results showed that (1) unilateral face or neck stimulation could elicit bilateral cortical activation, (2) mainly the face representation and face-hand junction areas, but not the conventional neck representation area, were activated by face or neck stimulation, and (3) the activation areas were larger when right face or neck was stimulated. In conclusion, the sensory cortical representation area of the anterior neck region was mainly at the junction of hand and face representation area and the activated area was larger when the right face or neck was stimulated.

  7. Cerebral, subcortical, and cerebellar activation evoked by selective stimulation of muscle and cutaneous afferents: an fMRI study.

    Science.gov (United States)

    Wardman, Daniel L; Gandevia, Simon C; Colebatch, James G

    2014-01-01

    Abstract We compared the brain areas that showed significant flow changes induced by selective stimulation of muscle and cutaneous afferents using fMRI BOLD imaging. Afferents arising from the right hand were studied in eight volunteers with electrical stimulation of the digital nerve of the index finger and over the motor point of the FDI muscle. Both methods evoked areas of significant activation cortically, subcortically, and in the cerebellum. Selective muscle afferent stimulation caused significant activation in motor-related areas. It also caused significantly greater activation within the contralateral precentral gyrus, insula, and within the ipsilateral cerebellum as well as greater areas of reduced blood flow when compared to the cutaneous stimuli. We demonstrated separate precentral and postcentral foci of excitation with muscle afferent stimulation. We conclude, contrary to the findings with evoked potentials, that muscle afferents evoke more widespread cortical, subcortical, and cerebellar activation than do cutaneous afferents. This emphasizes the importance, for studies of movement, of matching the kinematic aspects in order to avoid the results being confounded by alterations in muscle afferent activation. The findings are consistent with clinical observations of the movement consequences of sensory loss and may also be the basis for the contribution of disturbed sensorimotor processing to disorders of movement.

  8. Neural Response during the Activation of the Attachment System in Patients with Borderline Personality Disorder: An fMRI Study

    Science.gov (United States)

    Buchheim, Anna; Erk, Susanne; George, Carol; Kächele, Horst; Martius, Philipp; Pokorny, Dan; Spitzer, Manfred; Walter, Henrik

    2016-01-01

    Individuals with borderline personality disorder (BPD) are characterized by emotional instability, impaired emotion regulation and unresolved attachment patterns associated with abusive childhood experiences. We investigated the neural response during the activation of the attachment system in BPD patients compared to healthy controls using functional magnetic resonance imaging (fMRI). Eleven female patients with BPD without posttraumatic stress disorder (PTSD) and 17 healthy female controls matched for age and education were telling stories in the scanner in response to the Adult Attachment Projective Picture System (AAP), an eight-picture set assessment of adult attachment. The picture set includes theoretically-derived attachment scenes, such as separation, death, threat and potential abuse. The picture presentation order is designed to gradually increase the activation of the attachment system. Each picture stimulus was presented for 2 min. Analyses examine group differences in attachment classifications and neural activation patterns over the course of the task. Unresolved attachment was associated with increasing amygdala activation over the course of the attachment task in patients as well as controls. Unresolved controls, but not patients, showed activation in the right dorsolateral prefrontal cortex (DLPFC) and the rostral cingulate zone (RCZ). We interpret this as a neural signature of BPD patients’ inability to exert top-down control under conditions of attachment distress. These findings point to possible neural mechanisms for underlying affective dysregulation in BPD in the context of attachment trauma and fear. PMID:27531977

  9. Gene expression profiling of peri-implant healing of PLGA-Li+ implants suggests an activated Wnt signaling pathway in vivo.

    Directory of Open Access Journals (Sweden)

    Anna Thorfve

    Full Text Available Bone development and regeneration is associated with the Wnt signaling pathway that, according to literature, can be modulated by lithium ions (Li+. The aim of this study was to evaluate the gene expression profile during peri-implant healing of poly(lactic-co-glycolic acid (PLGA implants with incorporated Li+, while PLGA without Li+ was used as control, and a special attention was then paid to the Wnt signaling pathway. The implants were inserted in rat tibia for 7 or 28 days and the gene expression profile was investigated using a genome-wide microarray analysis. The results were verified by qPCR and immunohistochemistry. Histomorphometry was used to evaluate the possible effect of Li+ on bone regeneration. The microarray analysis revealed a large number of significantly differentially regulated genes over time within the two implant groups. The Wnt signaling pathway was significantly affected by Li+, with approximately 34% of all Wnt-related markers regulated over time, compared to 22% for non-Li+ containing (control; Ctrl implants. Functional cluster analysis indicated skeletal system morphogenesis, cartilage development and condensation as related to Li+. The downstream Wnt target gene, FOSL1, and the extracellular protein-encoding gene, ASPN, were significantly upregulated by Li+ compared with Ctrl. The presence of β-catenin, FOSL1 and ASPN positive cells was confirmed around implants of both groups. Interestingly, a significantly reduced bone area was observed over time around both implant groups. The presence of periostin and calcitonin receptor-positive cells was observed at both time points. This study is to the best of the authors' knowledge the first report evaluating the effect of a local release of Li+ from PLGA at the fracture site. The present study shows that during the current time frame and with the present dose of Li+ in PLGA implants, Li+ is not an enhancer of early bone growth, although it affects the Wnt signaling pathway.

  10. Receptor Activator of Nuclear Factor Kappa-B Ligand-Induced Local Osteoporotic Canine Mandible Model for the Evaluation of Peri-Implant Bone Regeneration.

    Science.gov (United States)

    Chang, Ah Ryum; Cho, Tae Hyung; Hwang, Soon Jung

    2017-08-24

    The canine mandible is useful for studying bone regeneration after dental implant placement. However, it is limited in investigations of peri-implant osteogenesis under osteoporotic conditions due to the insignificant osteoporotic effect of ovariectomy. This study aimed at establishing a local osteoporotic model without ovariectomy by using receptor activator of nuclear factor kappa-B ligand (RANKL) in a canine mandible model. This new model was used to evaluate the effects of injectable β-tricalcium phosphate (TCP) microsphere bone grafts on peri-implant bone regeneration under osteoporotic conditions with combinations of recombinant human bone morphogenetic protein-2 (rhBMP-2). A local osteoporotic canine mandible model was designed by creating a hole in the mandibular alveolar bone, then implanting a collagen sponge soaked with 20, 40, or 60 μg RANKL into the hole, and leaving it for 2 weeks. After the establishment of the dose for maximum osteoporotic bone loss at 40 μg of RANKL, the main surgery was performed. RANKL-soaked collagen sponges were removed, and dental implants were placed with bone grafts in five groups: implant only, TCP, and TCP + rhBMP-2 at 5, 15, and 45 μg. Peri-implant bone generation was determined by radiologic and histologic evaluations at 6 weeks after dental implant placement. On performing micro-computed tomography analysis, the group with TCP + 5 μg rhBMP-2 showed the highest bone volume than the other groups and a 22% increase (p model was useful for peri-implant bone regeneration under osteoporotic conditions such as those found in geriatric patients. The injectable β-TCP bone grafts used in this study were effective in peri-implant bone generation under osteoporotic conditions, and their efficiency was enhanced at 5 μg BMP-2 compared with higher concentrations of BMP-2.

  11. A Survey of Agreement Rate between Simple MTC and Post Contrast T1 Sequence MRI for Diagnosing Active Multiple Sclerosis Plaques

    Directory of Open Access Journals (Sweden)

    N. Farshchian

    2016-07-01

    Full Text Available Introduction & Objective: MS is the most common disabling neurological disorder. Identifying new active MS plaques at the onset and clinical status and faster onset of treatment as well as evaluating the response to treatment is important and MRI with contrast is the best indicator for these measures. Materials & Methods: This study was cross-sectional including 62 patients with diagnosed MS. Whose clinical symptoms suggested the recurrence of MS. They were referred to the radiol-ogy department to undergo brain MRI with injection for the diagnosis of active plaques by a neurologist,The Data were analyzed using statistical tests and SPSS 21 software. Results: Based on the sequences of post contrast T1, pre contrast MTC and post contrast MTC 74, 272 and 271 plaques were respectively discovered. Detection of active MS plaques on T1 sequences after injection were in poor accordance and had significant difference with MTC before and after injection. Moreover, detection of active MS plaques on MTC sequences be-fore injection were in good accordance and did not show significant difference with MTC se-quences after injection. Conclusion: Based on these results, it seems that the purpose of MRI in MS patients is deter-mining the amount of active plaques. Sequences of pre contrast and post contrast MTC are significantly more than sequences of post contrast T1. Therefore, using sequences of MTC can be helpful in MRI. (Sci J Hamadan Univ Med Sci 2016; 23 (2:97-102

  12. Many Neighbors are not Silent. fMRI Evidence for Global Lexical Activity in Visual Word Recognition.

    Directory of Open Access Journals (Sweden)

    Mario eBraun

    2015-07-01

    Full Text Available Many neurocognitive studies investigated the neural correlates of visual word recognition, some of which manipulated the orthographic neighborhood density of words and nonwords believed to influence the activation of orthographically similar representations in a hypothetical mental lexicon. Previous neuroimaging research failed to find evidence for such global lexical activity associated with neighborhood density. Rather, effects were interpreted to reflect semantic or domain general processing. The present fMRI study revealed effects of lexicality, orthographic neighborhood density and a lexicality by orthographic neighborhood density interaction in a silent reading task. For the first time we found greater activity for words and nonwords with a high number of neighbors. We propose that this activity in the dorsomedial prefrontal cortex reflects activation of orthographically similar codes in verbal working memory thus providing evidence for global lexical activity as the basis of the neighborhood density effect. The interaction of lexicality by neighborhood density in the ventromedial prefrontal cortex showed lower activity in response to words with a high number compared to nonwords with a high number of neighbors. In the light of these results the facilitatory effect for words and inhibitory effect for nonwords with many neighbors observed in previous studies can be understood as being due to the operation of a fast-guess mechanism for words and a temporal deadline mechanism for nonwords as predicted by models of visual word recognition. Furthermore, we propose that the lexicality effect with higher activity for words compared to nonwords in inferior parietal and middle temporal cortex reflects the operation of an identification mechanism and based on local lexico-semantic activity.

  13. The activL(®) Artificial Disc: a next-generation motion-preserving implant for chronic lumbar discogenic pain.

    Science.gov (United States)

    Yue, James J; Garcia, Rolando; Miller, Larry E

    2016-01-01

    Degeneration of the lumbar intervertebral discs is a leading cause of chronic low back pain in adults. Treatment options for patients with chronic lumbar discogenic pain unresponsive to conservative management include total disc replacement (TDR) or lumbar fusion. Until recently, only two lumbar TDRs had been approved by the US Food and Drug Administration - the Charité Artificial Disc in 2004 and the ProDisc-L Total Disc Replacement in 2006. In June 2015, a next-generation lumbar TDR received Food and Drug Administration approval - the activL(®) Artificial Disc (Aesculap Implant Systems). Compared to previous-generation lumbar TDRs, the activL(®) Artificial Disc incorporates specific design enhancements that result in a more precise anatomical match and allow a range of motion that better mimics the healthy spine. The results of mechanical and clinical studies demonstrate that the activL(®) Artificial Disc results in improved mechanical and clinical outcomes versus earlier-generation artificial discs and compares favorably to lumbar fusion. The purpose of this report is to describe the activL(®) Artificial Disc including implant characteristics, intended use, surgical technique, postoperative care, mechanical testing, and clinical experience to date.

  14. Comparision of detective effects of contrast-enhanced ultrasound and MRI on vascularization of hydroxyapatite after intraorbital implantation%超声造影与磁共振成像对义眼座植入后血管化检测的比较

    Institute of Scientific and Technical Information of China (English)

    徐柒华; 朱建刚; 邹大中; 郑永强

    2013-01-01

    Objective To compare the detective effects of contrast-enhanced ultrasound (CEUS) and MRI on vascularization of hydroxyapatite after intraorbital implantation and verify the feasibility of CEUS on vascularization detection of hydroxyapatite after intraorbital implantation.Methods CEUS and enhanced MRI were used to detect vascularization of 10 patients with intraorbital implantation of hydroxyapatite,and their hydroxyapatite reinforcement area size and complete vascularization time were compared.Results Both detective methods could show the vascularization process after intraorbital implantation of hydroxyapatite.Each month the size of reinforcement areas shown by both methods had no difference and the complete vascularization after intraorbital implantation of hydroxyapatite needed 5 to 6 months.CEUS gave better display of the dynamic process.Conclusion CEUS is an effective method to detect the vascularization of hydroxyapatite orbital implant,giving a better display of dynamic process than MRI.%目的 对超声造影和磁共振成像评价羟基磷灰石眶内植入术后血管化检测进行比较,验证超声造影对义眼座植入术后血管化检测的可行性.方法 分别使用超声造影及增强磁共振成像对10例植入羟基磷灰石义眼座术后进行血管化检测,对羟基磷灰石的强化面积及完全血管化时间进行比较.结果 两种检查方法都很好地显示了羟基磷灰石义眼座植入术后的血管化过程,每个月两种检查方法显示的强化面积经统计无差别,显示了羟基磷灰石眶内植入术后完全血管化时间是5~6个月.超声造影显示了更好的动态过程.结论 超声造影是一种检查羟基磷灰石义眼座血管化的有效方法,其显示的动态过程优于磁共振成像.

  15. An fMRI comparison of neural activity associated with recognition of familiar melodies in younger and older adults

    Directory of Open Access Journals (Sweden)

    Ritu eSikka

    2015-10-01

    Full Text Available Several studies of semantic memory in non-musical domains involving recognition of items from long-term memory have shown an age-related shift from the medial temporal lobe structures to the frontal lobe. However, the effects of aging on musical semantic memory remain unexamined. We compared activation associated with recognition of familiar melodies in younger and older adults. Recognition follows successful retrieval from the musical lexicon that comprises a lifetime of learned musical phrases. We used the sparse-sampling technique in fMRI to determine the neural correlates of melody recognition by comparing activation when listening to familiar versus unfamiliar melodies, and to identify age differences. Recognition-related cortical activation was detected in the right superior temporal, bilateral inferior and superior frontal, left middle orbitofrontal, bilateral precentral, and left supramarginal gyri. Region-of-interest analysis showed greater activation for younger adults in the left superior temporal gyrus and for older adults in the left superior frontal, left angular, and bilateral superior parietal regions. Our study provides powerful evidence for these musical memory networks due to a large sample (N = 40 that includes older adults. This study is the first to investigate the neural basis of melody recognition in older adults and to compare the findings to younger adults.

  16. Lower prefrontal activation during emotion regulation in subjects at ultrahigh risk for psychosis: an fMRI-study.

    Science.gov (United States)

    van der Velde, Jorien; Opmeer, Esther M; Liemburg, Edith J; Bruggeman, Richard; Nieboer, Roeline; Wunderink, Lex; Aleman, André

    2015-01-01

    Previous research has shown that patients with schizophrenia experience difficulties with emotion regulation and activate prefrontal regions to a lesser extent during reappraisal of emotional information. It has been suggested that problems in emotion regulation might precede the onset of psychosis. Therefore, it could be hypothesized that also individuals at ultrahigh risk (UHR) for developing psychosis experience difficulties with emotion regulation. The aim of the current study was to investigate whether individuals at UHR for developing psychosis show abnormal brain activation during reappraisal of negative pictures. Using functional magnetic resonance imaging (fMRI), we scanned 15 UHR participants and 16 matched healthy controls while performing an emotion regulation task. During this task, participants had to reappraise their negative emotion elicited by International Affective Picture System pictures. Furthermore, the reported use of reappraisal was examined with the emotion regulation questionnaire (ERQ). Individuals at UHR for psychosis showed less activation in the left ventrolateral prefrontal cortex during reappraisal compared with healthy controls. Furthermore, they reported less use of reappraisal in daily life (P=0.01; 95% CI (0.24-1.63)). These findings indicate that dysfunctional emotion regulation may already occur in individuals at risk for psychosis. These regulation difficulties are underpinned by less ventrolateral prefrontal cortex activation, and may result in high negative affect, lower social functioning, and high rates of psychotic symptoms.

  17. An fMRI study on cortical responses during active self-touch and passive touch from others

    Directory of Open Access Journals (Sweden)

    Rochelle eAckerley

    2012-08-01

    Full Text Available Active, self-touch and the passive touch from an external source engage comparable afferent mechanoreceptors on the touched skin site. However, touch directed to glabrous skin compared to hairy skin will activate different types of afferent mechanoreceptors. Despite perceptual similarities between touch to different body sites, it is likely that the touch information is processed differently. In the present study, we used functional magnetic resonance imaging (fMRI to elucidate the cortical differences in the neural signal of touch representations during active, self-touch and passive touch from another, to both glabrous (palm and hairy (arm skin, where a soft brush was used as the stimulus. There were two active touch conditions, where the participant used the brush in their right hand to stroke either their left palm or arm. There were two similar passive, touch conditions where the experimenter used an identical brush to stroke the same palm and arm areas on the participant. Touch on the left palm elicited a large, significant, positive blood-oxygenation level dependence (BOLD signal in right sensorimotor areas. Less extensive activity was found for touch to the arm. Separate somatotopical palm and arm representations were found in Brodmann area 3 of the right primary somatosensory cortex (SI and in both these areas, active stroking gave significantly higher signals than passive stroking. Active, self-touch elicited a positive BOLD signal in a network of sensorimotor cortical areas in the left hemisphere, compared to the resting baseline. In contrast, during passive touch, a significant negative BOLD signal was found in the left SI. Thus, each of the four conditions had a unique cortical signature despite similarities in afferent signalling or evoked perception. It is hypothesized that attentional mechanisms play a role in the modulation of the touch signal in the right SI, accounting for the differences found between active and passive touch.

  18. An fMRI study of neuronal activation in schizophrenia patients with and without previous cannabis use

    Directory of Open Access Journals (Sweden)

    Else-Marie eLøberg

    2012-10-01

    Full Text Available Previous studies have mostly shown positive effects of cannabis use on cognition in patients with schizophrenia, which could reflect lower neurocognitive vulnerability. There are however no studies comparing whether such cognitive differences have neuronal correlates. Thus, the aim of the present study was to compare whether patients with previous cannabis use differ in brain activation from patients who has never used cannabis. The patients groups were compared on the ability to up-regulate an effort mode network during a cognitive task and down-regulate activation in the same network during a task-absent condition. Task-present and task-absent brain activation was measured by functional magnetic resonance neuroimaging (fMRI. Twenty-six patients with a DSM-IV and ICD-10 diagnosis of schizophrenia were grouped into a previous cannabis user group and a no-cannabis group. An auditory dichotic listening task with instructions of attention focus on either the right or left ear stimulus was used to tap verbal processing, attention and cognitive control, calculated as an aggregate score. When comparing the two groups, there were remaining activations in the task-present condition for the cannabis group, not seen in the no-cannabis group, while there was remaining activation in the task-absent condition for the no-cannabis group, not seen in the cannabis group. Thus, the patients with previous cannabis use showed increased activation in an effort mode network and decreased activation in the default mode network as compared to the no-cannabis group. It is concluded that the present study show some differences in brain activation to a cognitively challenging task between previous cannabis and no-cannabis schizophrenia patients.

  19. Changes in brain activation patterns according to cross-training effect in serial reaction time task An functional MRI study

    Institute of Scientific and Technical Information of China (English)

    Yong Hyun Kwon; Jung Won Kwon; Ji Won Park

    2013-01-01

    Cross-training is a phenomenon related to motor learning, where motor performance of the untrained limb shows improvement in strength and skill execution following unilateral training of the homologous contralateral limb. We used functional MRI to investigate whether motor performance of the untrained limb could be improved using a serial reaction time task according to motor sequential learning of the trained limb, and whether these skill acquisitions led to changes in brain activation patterns. We recruited 20 right-handed healthy subjects, who were randomly allocated into training and control groups. The training group was trained in performance of a serial reaction time task using their non-dominant left hand, 40 minutes per day, for 10 days, over a period of 2 weeks. The control group did not receive training. Measurements of response time and percentile of response accuracy were performed twice during pre- and post-training, while brain functional MRI was scanned during performance of the serial reaction time task using the untrained right hand. In the training group, prominent changes in response time and percentile of response accuracy were observed in both the untrained right hand and the trained left hand between pre- and post-training. The control group showed no significant changes in the untrained hand between pre- and post-training. In the training group, the activated volume of the cortical areas related to motor function (i.e., primary motor cortex, premotor area, posterior parietal cortex) showed a gradual decrease, and enhanced cerebellar activation of the vermis and the newly activated ipsilateral dentate nucleus were observed during performance of the serial reaction time task using the untrained right hand, accompanied by the cross-motor learning effect. However, no significant changes were observed in the control group. Our findings indicate that motor skills learned over the 2-week training using the trained limb were transferred to the

  20. Effect of Observation of Simple Hand Movement on Brain Activations in Patients with Unilateral Cerebral Palsy: An fMRI Study

    Science.gov (United States)

    Dinomais, Mickael; Lignon, Gregoire; Chinier, Eva; Richard, Isabelle; Minassian, Aram Ter; The Tich, Sylvie N'Guyen

    2013-01-01

    The aim of this functional magnetic resonance imaging (fMRI) study was to examine and compare brain activation in patients with unilateral cerebral palsy (CP) during observation of simple hand movement performed by the paretic and nonparetic hand. Nineteen patients with clinical unilateral CP (14 male, mean age 14 years, 7-21 years) participated…

  1. Verum and sham acupuncture exert distinct cerebral activation in pain processing areas: a crossover fMRI investigation in healthy volunteers.

    Science.gov (United States)

    Usichenko, Taras I; Wesolowski, Toni; Lotze, Martin

    2015-06-01

    Although acupuncture is effective for treating pain, its site-specificity is questioned. The aim was to compare the cerebral responses of needling applied to an acupuncture point to the needling of a sham point, using functional magnetic resonance imaging (fMRI). Twenty-one healthy male volunteers were enrolled. Manual stimulation of the acupuncture (ST44) and sham points on the dorsum of the left foot was applied during fMRI in a crossover manner. fMRI data analysis was performed contrasting the ST44 and the sham conditions. Stimulation intensity, subjective discrimination of the needling site and the incidence of "Qi" sensation were additionally recorded. Stimulation of ST44 acupoint, in comparison to the sham procedure, was associated with an increased fMRI-activation in the primary somatosensory, the inferior parietal and the prefrontal cortex and the posterior insula. Sham needling was associated with increased activation in the anterior cingulate cortex and the anterior insula. Verum acupuncture increased the activity of discriminative somatosensory and cognitive pain processing areas of the brain, whereas sham needling activated the areas responsible for affective processing of pain. This may explain favorable effects of verum acupuncture in clinical studies about treatment of chronic pain patients.

  2. Pixel-by-pixel analysis of DCE-MRI curve shape patterns in knees of active and inactive juvenile idiopathic arthritis patients

    Energy Technology Data Exchange (ETDEWEB)

    Hemke, Robert; Lavini, Cristina; Maas, Mario [University of Amsterdam, Department of Radiology, Academic Medical Center, Amsterdam (Netherlands); Nusman, Charlotte M. [University of Amsterdam, Department of Radiology, Academic Medical Center, Amsterdam (Netherlands); University of Amsterdam, Department of Pediatric Hematology, Immunology, Rheumatology and Infectious Disease, Emma Children' s Hospital AMC, Amsterdam (Netherlands); Berg, J.M. van den; Schonenberg-Meinema, Dieneke; Kuijpers, Taco W. [University of Amsterdam, Department of Pediatric Hematology, Immunology, Rheumatology and Infectious Disease, Emma Children' s Hospital AMC, Amsterdam (Netherlands); Dolman, Koert M. [Department of Pediatric Rheumatology, Reade, Amsterdam (Netherlands); St. Lucas Andreas Hospital, Department of Pediatrics, Amsterdam (Netherlands); Rossum, Marion A.J. van [University of Amsterdam, Department of Pediatric Hematology, Immunology, Rheumatology and Infectious Disease, Emma Children' s Hospital AMC, Amsterdam (Netherlands); Department of Pediatric Rheumatology, Reade, Amsterdam (Netherlands)

    2014-07-15

    To compare DCE-MRI parameters and the relative number of time-intensity curve (TIC) shapes as derived from pixel-by-pixel DCE-MRI TIC shape analysis between knees of clinically active and inactive juvenile idiopathic arthritis (JIA) patients. DCE-MRI data sets were prospectively obtained. Patients were classified into two clinical groups: active disease (n = 43) and inactive disease (n = 34). Parametric maps, showing seven different TIC shape types, were created per slice. Statistical measures of different TIC shapes, maximal enhancement (ME), maximal initial slope (MIS), initial area under the curve (iAUC), time-to-peak (TTP), enhancing volume (EV), volume transfer constant (K {sup trans}), extravascular space fractional volume (V{sub e}) and reverse volume transfer constant (k{sub ep}) of each voxel were calculated in a three-dimensional volume-of-interest of the synovial membrane. Imaging findings from 77 JIA patients were analysed. Significantly higher numbers of TIC shape 4 (P = 0.008), median ME (P = 0.015), MIS (P = 0.001) and iAUC (P = 0.002) were observed in clinically active compared with inactive patients. TIC shape 5 showed higher presence in the clinically inactive patients (P = 0.036). The pixel-by-pixel DCE-MRI TIC shape analysis method proved capable of differentiating clinically active from inactive JIA patients by the difference in the number of TIC shapes, as well as the descriptive parameters ME, MIS and iAUC. (orig.)

  3. Endocrine activity of persistent organic pollutants accumulated in human silicone implants — Dosing in vitro assays by partitioning from silicone

    DEFF Research Database (Denmark)

    Gilbert, Dorothea; Mayer, Philipp; Pedersen, Mikael;

    2015-01-01

    Persistent organic pollutants (POPs) accumulated in human tissues may pose a risk for human health by interfering with the endocrine system. This study establishes a new link between actual human internal POP levels and the endocrine active dose in vitro, applying partitioning-controlled dosing...... from silicone to the H295R steroidogenesis assay: (1) Measured concentrations of POPs in silicone breast implants were taken from a recent study and silicone disks were loaded according to these measurements. (2) Silicone disks were transferred into H295R cell culture plates in order to control...

  4. Combined PET/MRI

    DEFF Research Database (Denmark)

    Bailey, D. L.; Pichler, B. J.; Gückel, B.

    2015-01-01

    This paper summarises key the