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Sample records for 3d-dynamic mri initial

  1. Estimation of Pulmonary Motion in Healthy Subjects and Patients with Intrathoracic Tumors Using 3D-Dynamic MRI: Initial Results

    Plathow, Christian; Schoebinger, Max; Meinzer, Heinz Peter [German Cancer Research Center, Heidelberg (Germany); Herth, Felix; Tuengerthal, Siegfried [Clinic of Thoracic Disease, Heidelberg (Germany); Kauczor, Hans Ulrich [University of Heidelberg, Heidelberg (Germany)

    2009-12-15

    To estimate a new technique for quantifying regional lung motion using 3D-MRI in healthy volunteers and to apply the technique in patients with intra- or extrapulmonary tumors. Intraparenchymal lung motion during a whole breathing cycle was quantified in 30 healthy volunteers using 3D-dynamic MRI (FLASH [fast low angle shot] 3D, TRICKS [time-resolved interpolated contrast kinetics]). Qualitative and quantitative vector color maps and cumulative histograms were performed using an introduced semiautomatic algorithm. An analysis of lung motion was performed and correlated with an established 2D-MRI technique for verification. As a proof of concept, the technique was applied in five patients with non-small cell lung cancer (NSCLC) and 5 patients with malignant pleural mesothelioma (MPM). The correlation between intraparenchymal lung motion of the basal lung parts and the 2D-MRI technique was significant (r = 0.89, p < 0.05). Also, the vector color maps quantitatively illustrated regional lung motion in all healthy volunteers. No differences were observed between both hemithoraces, which was verified by cumulative histograms. The patients with NSCLC showed a local lack of lung motion in the area of the tumor. In the patients with MPM, there was global diminished motion of the tumor bearing hemithorax, which improved significantly after chemotherapy (CHT) (assessed by the 2D- and 3D-techniques) (p < 0.01). Using global spirometry, an improvement could also be shown (vital capacity 2.9 {+-} 0.5 versus 3.4 L {+-} 0.6, FEV1 0.9 {+-} 0.2 versus 1.4 {+-} 0.2 L) after CHT, but this improvement was not significant. A 3D-dynamic MRI is able to quantify intraparenchymal lung motion. Local and global parenchymal pathologies can be precisely located and might be a new tool used to quantify even slight changes in lung motion (e.g. in therapy monitoring, follow-up studies or even benign lung diseases)

  2. Scaling in Gravitational Clustering, 2D and 3D Dynamics

    Munshi, D; Melott, A L; Schäffer, R

    1999-01-01

    Perturbation Theory (PT) applied to a cosmological density field with Gaussian initial fluctuations suggests a specific hierarchy for the correlation functions when the variance is small. In particular quantitative predictions have been made for the moments and the shape of the one-point probability distribution function (PDF) of the top-hat smoothed density. In this paper we perform a series of systematic checks of these predictions against N-body computations both in 2D and 3D with a wide range of featureless power spectra. In agreement with previous studies, we found that the reconstructed PDF-s work remarkably well down to very low probabilities, even when the variance approaches unity. Our results for 2D reproduce the features for the 3D dynamics. In particular we found that the PT predictions are more accurate for spectra with less power on small scales. The nonlinear regime has been explored with various tools, PDF-s, moments and Void Probability Function (VPF). These studies have been done with unprec...

  3. Innovative LIDAR 3D Dynamic Measurement System to estimate fruit-tree leaf area.

    Sanz-Cortiella, Ricardo; Llorens-Calveras, Jordi; Escolà, Alexandre; Arnó-Satorra, Jaume; Ribes-Dasi, Manel; Masip-Vilalta, Joan; Camp, Ferran; Gràcia-Aguilá, Felip; Solanelles-Batlle, Francesc; Planas-DeMartí, Santiago; Pallejà-Cabré, Tomàs; Palacin-Roca, Jordi; Gregorio-Lopez, Eduard; Del-Moral-Martínez, Ignacio; Rosell-Polo, Joan R

    2011-01-01

    In this work, a LIDAR-based 3D Dynamic Measurement System is presented and evaluated for the geometric characterization of tree crops. Using this measurement system, trees were scanned from two opposing sides to obtain two three-dimensional point clouds. After registration of the point clouds, a simple and easily obtainable parameter is the number of impacts received by the scanned vegetation. The work in this study is based on the hypothesis of the existence of a linear relationship between the number of impacts of the LIDAR sensor laser beam on the vegetation and the tree leaf area. Tests performed under laboratory conditions using an ornamental tree and, subsequently, in a pear tree orchard demonstrate the correct operation of the measurement system presented in this paper. The results from both the laboratory and field tests confirm the initial hypothesis and the 3D Dynamic Measurement System is validated in field operation. This opens the door to new lines of research centred on the geometric characterization of tree crops in the field of agriculture and, more specifically, in precision fruit growing.

  4. Innovative LIDAR 3D Dynamic Measurement System to Estimate Fruit-Tree Leaf Area

    Ignacio Del-Moral-Martínez

    2011-05-01

    Full Text Available In this work, a LIDAR-based 3D Dynamic Measurement System is presented and evaluated for the geometric characterization of tree crops. Using this measurement system, trees were scanned from two opposing sides to obtain two three-dimensional point clouds. After registration of the point clouds, a simple and easily obtainable parameter is the number of impacts received by the scanned vegetation. The work in this study is based on the hypothesis of the existence of a linear relationship between the number of impacts of the LIDAR sensor laser beam on the vegetation and the tree leaf area. Tests performed under laboratory conditions using an ornamental tree and, subsequently, in a pear tree orchard demonstrate the correct operation of the measurement system presented in this paper. The results from both the laboratory and field tests confirm the initial hypothesis and the 3D Dynamic Measurement System is validated in field operation. This opens the door to new lines of research centred on the geometric characterization of tree crops in the field of agriculture and, more specifically, in precision fruit growing.

  5. PET/MRI in head and neck cancer: initial experience

    Platzek, Ivan; Laniado, Michael [Dresden University Hospital, Department of Radiology, Dresden (Germany); Beuthien-Baumann, Bettina [Dresden University Hospital, Department of Nuclear Medicine, Dresden (Germany); Schneider, Matthias [Dresden University Hospital, Oral and Maxillofacial Surgery, Dresden (Germany); Gudziol, Volker [Dresden University Hospital, Department of Otolaryngology, Dresden (Germany); Langner, Jens; Schramm, Georg; Hoff, Joerg van den [Institute of Bioinorganic and Radiopharmaceutical Chemistry, Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany); Kotzerke, Joerg [Dresden University Hospital, Nuclear Medicine, Dresden (Germany)

    2013-01-15

    To evaluate the feasibility of PET/MRI (positron emission tomography/magnetic resonance imaging) with FDG ({sup 18}F-fluorodeoxyglucose) for initial staging of head and neck cancer. The study group comprised 20 patients (16 men, 4 women) aged between 52 and 81 years (median 64 years) with histologically proven squamous cell carcinoma of the head and neck region. The patients underwent a PET scan on a conventional scanner and a subsequent PET/MRI examination on a whole-body hybrid system. FDG was administered intravenously prior to the conventional PET scan (267-395 MBq FDG, 348 MBq on average). The maximum standardized uptake values (SUV{sub max}) of the tumour and of both cerebellar hemispheres were determined for both PET datasets. The numbers of lymph nodes with increased FDG uptake were compared between the two PET datasets. No MRI-induced artefacts where observed in the PET images. The tumour was detected by PET/MRI in 17 of the 20 patients, by PET in 16 and by MRI in 14. The PET/MRI examination yielded significantly higher SUV{sub max} than the conventional PET scanner for both the tumour (p < 0.0001) and the cerebellum (p = 0.0009). The number of lymph nodes with increased FDG uptake detected using the PET dataset from the PET/MRI system was significantly higher the number detected by the stand-alone PET system (64 vs. 39, p = 0.001). The current study demonstrated that PET/MRI of the whole head and neck region is feasible with a whole-body PET/MRI system without impairment of PET or MR image quality. (orig.)

  6. Assessment of pulmonary parenchyma perfusion with FAIR in comparison with DCE-MRI-Initial results

    Fan Li [Department of Radiology, ChangZheng Hospital Affiliated to Second Military Medical University, No. 415 Fengyang Road, Shanghai 200003 (China)], E-mail: fanli0930@163.com; Liu Shiyuan [Department of Radiology, ChangZheng Hospital Affiliated to Second Military Medical University, No. 415 Fengyang Road, Shanghai 200003 (China); Sun Fei [GE Healthcare China (China)], E-mail: Fei.sun@med.ge.com; Xiao Xiangsheng [Department of Radiology, ChangZheng Hospital Affiliated to Second Military Medical University, No. 415 Fengyang Road, Shanghai 200003 (China)], E-mail: lizhaobin79@163.com

    2009-04-15

    Objective: The aim of this study was to assess pulmonary parenchyma perfusion with flow-sensitive alternating inversion recovery (FAIR) in comparison with 3D dynamic contrast-enhanced (DCE) imaging in healthy volunteers and in patients with pulmonary embolism or lung cancer. Materials and methods: Sixteen healthy volunteers and 16 patients with pulmonary embolism (5 cases) or lung cancer (11 cases) were included in this study. Firstly, the optimized inversion time of FAIR (TI) was determined in 12 healthy volunteers. Then, FAIR imaging with the optimized TI was performed followed by DCE-MRI on the other 4 healthy volunteers and 16 patients. Tagging efficiency of lung and SNR of perfusion images were calculated with different TI values. In the comparison of FAIR with DCE-MRI, the homogeneity of FAIR and DCE-MRI perfusion was assessed. In the cases of perfusion abnormality, the contrast between normal lung and perfusion defects was quantified by calculating a normalized signal intensity ratio. Results: One thousand milliseconds was the optimal TI, which generated the highest lung tagging efficiency and second highest PBF SNR. In the volunteers, the signal intensity of perfusion images acquired with both FAIR and DCE-MRI was homogeneous. Wedged-shaped or triangle perfusion defects were visualized in five pulmonary embolisms and three lung cancer cases. There was no significant statistical difference in signal intensity ratio between FAIR and DCE-MRI (P > 0.05). In the rest of eight lung cancers, all the lesions showed low perfusion against the higher perfused pulmonary parenchyma in both FAIR and DCE-MRI. Conclusion: Pulmonary parenchyma perfusion imaging with FAIR was feasible, consistent and could obtain similar functional information to that from DCE-MRI.

  7. The optimizations of CGH generation algorithms based on multiple GPUs for 3D dynamic holographic display

    Yang, Dan; Liu, Juan; Zhang, Yingxi; Li, Xin; Wang, Yongtian

    2016-10-01

    Holographic display has been considered as a promising display technology. Currently, low-speed generation of holograms with big holographic data is one of crucial bottlenecks for three dimensional (3D) dynamic holographic display. To solve this problem, the acceleration method computation platform is presented based on look-up table point source method. The computer generated holograms (CGHs) acquisition is sped up by offline file loading and inline calculation optimization, where a pure phase CGH with gigabyte data is encoded to record an object with 10 MB sampling data. Both numerical simulation and optical experiment demonstrate that the CGHs with 1920×1080 resolution by the proposed method can be applied to the 3D objects reconstruction with high quality successfully. It is believed that the CGHs with huge data can be generated by the proposed method with high speed for 3D dynamic holographic display in near future.

  8. 3D Dynamics of 4D Topological BF Theory With Boundary

    Amoretti, Andrea; Maggiore, Nicola; Magnoli, Nicodemo

    2012-01-01

    We consider the four dimensional abelian topological BF theory with a planar boundary introduced following the Symanzik's method. We find the most general boundary conditions compatible with the fields equations broken by the boundary. The residual gauge invariance is described by means of two Ward identities which generate an algebra of conserved currents. We interpret this algebra as canonical commutation relations of fields, which we use to construct a three dimensional Lagrangian. As a remarkable by-product, the (unique) boundary condition which we found, can be read as a duality relation between 3D dynamical variables.

  9. Intraoperative 3-tesla MRI in the management of paediatric cranial tumours - initial experience

    Avula, Shivaram; Garlick, Deborah; Abernethy, Laurence J. [Alder Hey Children' s NHS Foundation Trust, Department of Radiology, Liverpool (United Kingdom); Mallucci, Connor L. [Alder Hey Children' s Hospital, Department of Neurosurgery, Liverpool (United Kingdom); Pizer, Barry [Alder Hey Children' s Hospital, Department of Oncology, Liverpool (United Kingdom); Crooks, Daniel [Walton Centre for Neurology and Neurosurgery, Department of Pathology, Liverpool (United Kingdom)

    2012-02-15

    Intraoperative MRI (ioMRI) has been gaining recognition because of its value in the neurosurgical management of cranial tumours. There is limited documentation of its value in children. To review the initial experience of a paediatric 3-Tesla ioMRI unit in the management of cranial tumours. Thirty-eight children underwent ioMRI during 40 cranial tumour resections using a 3-Tesla MR scanner co-located with the neurosurgical operating theatre. IoMRI was performed to assess the extent of tumour resection and/or to update neuronavigation. The intraoperative and follow-up scans, and the clinical records were reviewed. In 27/40 operations, complete resection was intended. IoMRI confirmed complete resection in 15/27 (56%). As a consequence, surgical resection was extended in 5/27 (19%). In 6/27 (22%), ioMRI was equivocal for residual tumour. In 13/40 (33%) operations, the surgical aim was to partially resect the tumour. In 7 of the 13 (54%), surgical resection was extended following ioMRI. In our initial experience, ioMRI has increased the rate of complete resection, with intraoperative surgical strategy being modified in 30% of procedures. Collaborative analysis of ioMRI by the radiologist and neurosurgeon is vital to avoid errors in interpretation. (orig.)

  10. Initial tests of a prototype MRI-compatible PET imager

    Raylman, Raymond R.; Majewski, Stan; Lemieux, Susan; Velan, S. Sendhil; Kross, Brain; Popov, Vladimir; Smith, Mark F.; Weisenberger, Andrew G.; Wojcik, Randy

    2006-12-01

    Multi-modality imaging is rapidly becoming a valuable tool in the diagnosis of disease and in the development of new drugs. Functional images produced with PET fused with anatomical structure images created by MRI, will allow the correlation of form with function. Our group (a collaboration of West Virginia University and Jefferson Lab) is developing a system to acquire MRI and PET images contemporaneously. The prototype device consists of two opposed detector heads, operating in coincidence mode with an active FOV of 5×5×4 cm 3. Each MRI-PET detector module consists of an array of LSO detector elements (2.5×2.5×15 mm 3) coupled through a long fiber optic light guide to a single Hamamatsu flat panel PSPMT. The fiber optic light guide is made of a glued assembly of 2 mm diameter acrylic fibers with a total length of 2.5 m. The use of a light guides allows the PSPMTs to be positioned outside the bore of the 3 T General Electric MRI scanner used in the tests. Photon attenuation in the light guides resulted in an energy resolution of ˜60% FWHM, interaction of the magnetic field with PSPMT further reduced energy resolution to ˜85% FWHM. Despite this effect, excellent multi-plane PET and MRI images of a simple disk phantom were acquired simultaneously. Future work includes improved light guides, optimized magnetic shielding for the PSPMTs, construction of specialized coils to permit high-resolution MRI imaging, and use of the system to perform simultaneous PET and MRI or MR-spectroscopy .

  11. Initial tests of a prototype MRI-compatible PET imager

    Raylman, Raymond R. [Center for Advanced Imaging, Department of Radiology, West Virginia University, HSB Box 9236, Morgantown, WV (United States)]. E-mail: rraylman@wvu.edu; Majewski, Stan [Detector Group, Physics Division, Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Lemieux, Susan [Center for Advanced Imaging, Department of Radiology, West Virginia University, HSB Box 9236, Morgantown, WV (United States); Velan, S. Sendhil [Center for Advanced Imaging, Department of Radiology, West Virginia University, HSB Box 9236, Morgantown, WV (United States); Kross, Brain [Detector Group, Physics Division, Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Popov, Vladimir [Detector Group, Physics Division, Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Smith, Mark F. [Detector Group, Physics Division, Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Weisenberger, Andrew G. [Detector Group, Physics Division, Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Wojcik, Randy [Detector Group, Physics Division, Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

    2006-12-20

    Multi-modality imaging is rapidly becoming a valuable tool in the diagnosis of disease and in the development of new drugs. Functional images produced with PET fused with anatomical structure images created by MRI, will allow the correlation of form with function. Our group (a collaboration of West Virginia University and Jefferson Lab) is developing a system to acquire MRI and PET images contemporaneously. The prototype device consists of two opposed detector heads, operating in coincidence mode with an active FOV of 5x5x4 cm{sup 3}. Each MRI-PET detector module consists of an array of LSO detector elements (2.5x2.5x15 mm{sup 3}) coupled through a long fiber optic light guide to a single Hamamatsu flat panel PSPMT. The fiber optic light guide is made of a glued assembly of 2 mm diameter acrylic fibers with a total length of 2.5 m. The use of a light guides allows the PSPMTs to be positioned outside the bore of the 3 T General Electric MRI scanner used in the tests. Photon attenuation in the light guides resulted in an energy resolution of {approx}60% FWHM, interaction of the magnetic field with PSPMT further reduced energy resolution to {approx}85% FWHM. Despite this effect, excellent multi-plane PET and MRI images of a simple disk phantom were acquired simultaneously. Future work includes improved light guides, optimized magnetic shielding for the PSPMTs, construction of specialized coils to permit high-resolution MRI imaging, and use of the system to perform simultaneous PET and MRI or MR-spectroscopy.

  12. Representation and coding of large-scale 3D dynamic maps

    Cohen, Robert A.; Tian, Dong; Krivokuća, Maja; Sugimoto, Kazuo; Vetro, Anthony; Wakimoto, Koji; Sekiguchi, Shunichi

    2016-09-01

    combined with depth and color measurements of the surrounding environment. Localization could be achieved with GPS, inertial measurement units (IMU), cameras, or combinations of these and other devices, while the depth measurements could be achieved with time-of-flight, radar or laser scanning systems. The resulting 3D maps, which are composed of 3D point clouds with various attributes, could be used for a variety of applications, including finding your way around indoor spaces, navigating vehicles around a city, space planning, topographical surveying or public surveying of infrastructure and roads, augmented reality, immersive online experiences, and much more. This paper discusses application requirements related to the representation and coding of large-scale 3D dynamic maps. In particular, we address requirements related to different types of acquisition environments, scalability in terms of progressive transmission and efficiently rendering different levels of details, as well as key attributes to be included in the representation. Additionally, an overview of recently developed coding techniques is presented, including an assessment of current performance. Finally, technical challenges and needs for future standardization are discussed.

  13. A 3D dynamical model of the colliding winds in binary systems

    Parkin, E R

    2008-01-01

    We present a 3D dynamical model of the orbital induced curvature of the wind-wind collision region in binary star systems. Momentum balance equations are used to determine the position and shape of the contact discontinuity between the stars, while further downstream the gas is assumed to behave ballistically. An archimedean spiral structure is formed by the motion of the stars, with clear resemblance to high resolution images of the so-called ``pinwheel nebulae''. A key advantage of this approach over grid or smoothed particle hydrodynamic models is its significantly reduced computational cost, while it also allows the study of the structure obtained in an eccentric orbit. The model is relevant to symbiotic systems and Gamma-ray binaries, as well as systems with O-type and Wolf-Rayet stars. As an example application, we simulate the X-ray emission from hypothetical O+O and WR+O star binaries, and describe a method of ray tracing through the 3D spiral structure to account for absorption by the circumstellar m...

  14. Disks controlling chaos in a 3D dynamical model for elliptical galaxies

    Zotos, Euaggelos E

    2011-01-01

    A 3D dynamical model with a quasi-homogeneous core and a disk component is used for the chaos control in the central parts of elliptical galaxy. Numerical experiments in the 2D system show a very complicated phase plane with a large chaotic sea, considerable sticky layers and a large number of islands, produced by secondary resonances. When the mass of the disk increases, the chaotic regions decrease gradually, and, finally, a new phase plane with only regular orbits appears. This evolution indicates that disks in elliptical galaxies can act as the chaos controllers. Starting from the results obtained in the 2D system, we locate the regions in the phase space of the 3D system, producing regular and chaotic orbits. For this we introduce and use a new dynamical parameter, the S(w) spectrum, which proves to be useful as a fast indicator and allows us to distinguish the regular motion from chaos in the 3D potentials. Other methods for detecting chaos are also discussed.

  15. Outcome of MRI-guided vacuum-assisted breast biopsy – initial experience at Institute of Oncology Ljubljana, Slovenia

    Zebic-Sinkovec, Marta; Hertl, Kristijana; Kadivec, Maksimiljan; Cavlek, Mihael; Podobnik, Gasper; Snoj, Marko

    2012-01-01

    Background. Like all breast imaging modalities MRI has limited specificity and the positive predictive value for lesions detected by MRI alone ranges between 15 and 50%. MRI guided procedures (needle biopsy, presurgical localisation) are mandatory for suspicious findings visible only at MRI, with potential influence on therapeutic decision. The aim of this retrospective study was to evaluate our initial clinical experience with MRI-guided vacuum-assisted breast biopsy as an alternative to sur...

  16. Initial Incidence of White Matter Hyperintensities on MRI in Astronauts

    Norcross, Jason; Sherman, Paul; McGuire, Steve; Kochunov, Peter

    2016-01-01

    Introduction: Previous literature has described the increase in white matter hyperintensity (WMH) burden associated with hypobaric exposure in the U-2 and altitude chamber operating personnel. Although astronauts have similar hypobaric exposure pressures to the U2 pilot population, astronauts have far fewer exposures and each exposure would be associated with a much lower level of decompression stress due to rigorous countermeasures to prevent decompression sickness. Therefore, we postulated that the WMH burden in the astronaut population would be less than in U2 pilots. Methods: Twenty-one post-flight de-identified astronaut MRIs (5 mm slice thickness FLAIR sequences) were evaluated for WMH count and volume. The only additional data provided was an age range of the astronauts (43-57) and if they had ever performed an EVA (13 yes, 8 no). Results: WMH count in these 21 astronaut MRI was 21.0 +/- 24.8 (mean+/- SD) and volume was 0.382 +/- 0.602 ml, which was significantly higher than previously published results for the U2 pilots. No significant differences between EVA and no EVA groups existed. Age range of astronaut population is not directly comparable to the U2 population. Discussion: With significantly less frequent (sometimes none) and less stressful hypobaric exposures, yet a much higher incidence of increased WMH, this indicates the possibility of additional mechanisms beyond hypobaric exposure. This increase unlikely to be attributable just to the differences in age between astronauts and U2 pilots. Forward work includes continuing review of post-flight MRI and evaluation of pre to post flight MRI changes if available. Data mining for potential WMH risk factors includes collection of age, sex, spaceflight experience, EVA hours, other hypobaric exposures, hyperoxic exposures, radiation, high performance aircraft experience and past medical history. Finally, neurocognitive and vision/eye results will be evaluated for any evidence of impairment linked to

  17. Biologic response of inguinal hernia prosthetics: a comparative study of conventional static meshes versus 3D dynamic implants.

    Amato, Giuseppe; Romano, Giorgio; Agrusa, Antonino; Marasa, Salvatore; Cocorullo, Gianfranco; Gulotta, Gaspare; Goetze, Thorsten; Puleio, Roberto

    2015-01-01

    Despite improvements in prosthetics and surgical techniques, the rate of complications following inguinal hernia repair remains high. Among these, discomfort and chronic pain have become a source of increasing concern among surgeons. Poor quality of tissue ingrowth, such as thin scar plates or shrinking scars-typical results with conventional static implants and plugs-may contribute to these adverse events. Recently, a new type of 3D dynamically responsive implant was introduced to the market. This device, designed to be placed fixation-free, seems to induce ingrowth of viable and structured tissue instead of regressive fibrotic scarring. To elucidate the differences in biologic response between the conventional static meshes and this 3D dynamically responsive implant, a histological comparison was planned. The aim of this study was to determine the quality of tissue incorporation in both types of implants excised after short, medium, and long periods post-implantation. The results showed large differences in the biologic responses between the two implant types. Histologically, the 3D dynamic implant showed development of tissue elements more similar to natural abdominal wall structures, such as the ingrowth of loose and well-hydrated connective tissue, well-formed vascular structures, elastic fibers, and mature nerves, with negligible or absent inflammatory response. All these characteristics were completely absent in the conventional static implants, where a persistent inflammatory reaction was associated with thin, hardened, and shrunken fibrotic scar formation. Consequently, as herniation is a degenerative process, the 3D dynamic implants, which induce regeneration of the typical groin components, seem to address its pathogenesis.

  18. Primary Sjoegren's syndrome initially manifested by optic neuritis: MRI findings

    Kadota, Y.; Tokumaru, A.M.; Kohyama, S.; Okizuka, H.; Kaji, T.; Kusano, S. [Department of Radiology, National Defense Medical College, Saitama (Japan); Kamakura, K. [Department of Internal Medicine, National Defense Medical College, Saitama (Japan)

    2002-04-01

    We herein describe the MRI findings in a patient clinically diagnosed with primary Sjoegren's syndrome (SjS) initially manifested by retrobulbar optic neuritis. A 63-year-old woman suddenly had left ocular pain and progressive visual disturbance. MR T2-weighted images revealed hyperintensity in the left optic nerve, with swelling. Contrast-enhanced T1-weighted images showed no abnormal enhancement. Follow-up MRI 6 months after admission revealed no significant changes in the affected optic nerve. To our knowledge, optic neuritis as a complication of SjS has been reported in ten patients [1, 2, 3, 4, 5, 6] and MRI findings in only one of them [6]. We thought MR images were useful for visualizing optic nerve involvement in SjS and observing its course. (orig.)

  19. Posture-Dependent Human 3He Lung Imaging in an Open Access MRI System: Initial Results

    Tsai, L L; Li, C -H; Rosen, M S; Patz, S; Walsworth, R L

    2007-01-01

    The human lung and its functions are extremely sensitive to orientation and posture, and debate continues as to the role of gravity and the surrounding anatomy in determining lung function and heterogeneity of perfusion and ventilation. However, study of these effects is difficult. The conventional high-field magnets used for most hyperpolarized 3He MRI of the human lung, and most other common radiological imaging modalities including PET and CT, restrict subjects to lying horizontally, minimizing most gravitational effects. In this paper, we briefly review the motivation for posture-dependent studies of human lung function, and present initial imaging results of human lungs in the supine and vertical body orientations using inhaled hyperpolarized 3He gas and an open-access MRI instrument. The open geometry of this MRI system features a "walk-in" capability that permits subjects to be imaged in vertical and horizontal positions, and potentially allows for complete rotation of the orientation of the imaging su...

  20. Rapid 3D dynamic arterial spin labeling with a sparse model-based image reconstruction.

    Zhao, Li; Fielden, Samuel W; Feng, Xue; Wintermark, Max; Mugler, John P; Meyer, Craig H

    2015-11-01

    Dynamic arterial spin labeling (ASL) MRI measures the perfusion bolus at multiple observation times and yields accurate estimates of cerebral blood flow in the presence of variations in arterial transit time. ASL has intrinsically low signal-to-noise ratio (SNR) and is sensitive to motion, so that extensive signal averaging is typically required, leading to long scan times for dynamic ASL. The goal of this study was to develop an accelerated dynamic ASL method with improved SNR and robustness to motion using a model-based image reconstruction that exploits the inherent sparsity of dynamic ASL data. The first component of this method is a single-shot 3D turbo spin echo spiral pulse sequence accelerated using a combination of parallel imaging and compressed sensing. This pulse sequence was then incorporated into a dynamic pseudo continuous ASL acquisition acquired at multiple observation times, and the resulting images were jointly reconstructed enforcing a model of potential perfusion time courses. Performance of the technique was verified using a numerical phantom and it was validated on normal volunteers on a 3-Tesla scanner. In simulation, a spatial sparsity constraint improved SNR and reduced estimation errors. Combined with a model-based sparsity constraint, the proposed method further improved SNR, reduced estimation error and suppressed motion artifacts. Experimentally, the proposed method resulted in significant improvements, with scan times as short as 20s per time point. These results suggest that the model-based image reconstruction enables rapid dynamic ASL with improved accuracy and robustness.

  1. Negative predictive value of multiparametric MRI for prostate cancer detection: Outcome of 5-year follow-up in men with negative findings on initial MRI studies

    Itatani, R., E-mail: banguliao@gmail.com [Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1, Honjo, Kumamoto 860-8556 (Japan); Department of Radiology, Kumamoto Chuo Hospital, 1-5-1, Tainoshima, Kumamoto 862-0965 (Japan); Namimoto, T. [Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1, Honjo, Kumamoto 860-8556 (Japan); Atsuji, S.; Katahira, K.; Morishita, S. [Department of Radiology, Kumamoto Chuo Hospital, 1-5-1, Tainoshima, Kumamoto 862-0965 (Japan); Kitani, K.; Hamada, Y. [Department of Urology, Kumamoto Chuo Hospital, 1-5-1, Tainoshima, Kumamoto 862-0965 (Japan); Kitaoka, M. [Department of Pathology, Kumamoto Chuo Hospital, 1-5-1, Tainoshima, Kumamoto 862-0965 (Japan); Nakaura, T. [Department of Diagnostic Radiology, Amakusa Medical Center, Kameba 854-1, Amakusa, Kumamoto 863-0046 (Japan); Yamashita, Y. [Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1, Honjo, Kumamoto 860-8556 (Japan)

    2014-10-15

    Highlights: • We assess the negative predictive value of multiparametric MRI for prostate cancer. • Patients with positive prostate biopsy findings were defined as false-negative. • Patients with negative initial prostate biopsy findings were followed up for 5 years. • The negative predictive value was 89.6% for significant prostate cancer. • MRI is a useful tool to rule out significant prostate cancer before biopsy. - Abstract: Objective: To assess the clinical negative predictive value (NPV) of multiparametric MRI (mp-MRI) for prostate cancer in a 5-year follow-up. Materials and methods: One hundred ninety-three men suspected of harboring prostate cancer with negative MRI findings were included. Patients with positive transrectal ultrasound (TRUS)-guided biopsy findings were defined as false-negative. Patients with negative initial TRUS-guided biopsy findings were followed up and only patients with negative findings by digital rectal examination, MRI, and repeat biopsy and no increase in PSA at 5-year follow-up were defined as “clinically negative”. The clinical NPV of mp-MRI was calculated. For quantitative analysis, mean signal intensity on T2-weighted images and the mean apparent diffusion coefficient value on ADC maps of the initial MRI studies were compared between peripheral-zone (PZ) cancer and the normal PZ based on pathologic maps of patients who had undergone radical prostatectomy. Results: The clinical NPV of mp-MRI was 89.6% for significant prostate cancer. Small cancers, prostatitis, and benign prostatic hypertrophy masking prostate cancer returned false-negative results. Quantitative analysis showed that there was no significant difference between PZ cancer and the normal PZ. Conclusion: The mp-MRI revealed a high clinical NPV and is a useful tool to rule out clinically significant prostate cancer before biopsy.

  2. MRI-guided percutaneous laser ablation of small renal cell carcinoma: Initial clinical experience

    Kariniemi, Juho; Ojala, Risto; Hellstroem, Pekka; Sequeiros, Roberto Blanco (Dept. of Radiology, Dept. of Surgery, Oulu Univ. Hospital, Oulu (Finland)), e-mail: juho.kariniemi@oulu.fi

    2010-05-15

    Background: The number of detected small renal cell carcinomas (RCCs) has been rising, largely due to advances in imaging. Open surgical resection is the standard management of small RCCs; however, imaging-guided percutaneous ablative therapies have emerged as a minimally invasive treatment alternative, especially for patients who are poor candidates for surgery. Purpose: To evaluate the initial clinical experience of magnetic resonance imaging (MRI)-guided percutaneous laser ablation of small RCCs. Material and Methods: Eight patients with 10 tumors were treated with percutaneous MRI-guided laser ablation. All tumors (diameter range 1.5-3.8 cm, mean 2.7 cm) were biopsy-proven RCCs. By using a 0.23 T open MRI system and general anesthesia in patients, one to four (mean 2.6) laser fibers were placed and the tumors were ablated under near real-time MRI control by observing the signal void caused by the temperature change in the heated tissue. The treatment was considered successful if the tumor showed no contrast enhancement at follow-up imaging. Results: All except one tumor were successfully ablated in one session. The first patient treated showed enhancing residual tumor in post-procedural MRI; she has thus far declined retreatment. One complication, a myocardial infarction, occurred; all other patients tolerated the procedure well. No local recurrence was discovered during the follow-up (range 12-30 months, mean 20 months). Conclusion: In this small group of patients with relatively short follow-up period, MRI-guided percutaneous laser ablation proved to be a promising treatment option for small RCCs

  3. MRI

    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 ...

  4. 3D Dynamic Finite Element Analysis of the Nonuniform Residual Stress in Ultrasonic Impact Treatment Process

    Hu, Shengsun; Guo, Chaobo; Wang, Dongpo; Wang, Zhijiang

    2016-09-01

    The nonuniform distributions of the residual stress were simulated by a 3D finite element model to analyze the elastic-plastic dynamic ultrasonic impact treatment (UIT) process of multiple impacts on the 2024 aluminum alloy. The evolution of the stress during the impact process was discussed. The successive impacts during the UIT process improve the uniformity of the plastic deformation and decrease the maximum compressive residual stress beneath the former impact indentations. The influences of different controlled parameters, including the initial impact velocity, pin diameter, pin tip, device moving, and offset distances, on the residual stress distributions were analyzed. The influences of the controlled parameters on the residual stress distributions are apparent in the offset direction due to the different surface coverage in different directions. The influences can be used to understand the UIT process and to obtain the desired residual stress by optimizing the controlled parameters.

  5. The 3D Dynamical Structure of the Supernova-Driven Interstellar Medium

    Avillez, M. A.; Ballesteros-Paredes, J.; Mac Low, M.-M.

    2000-05-01

    Large scale modelling of the interstellar gas in the disk and halo has been carried out with a three-dimensional hydrodynamical code that uses adapted mesh refinement combined with message passing interface calls. The model includes a gravitational field provided by the stars in the disk, an ideal-gas equation of state, and an approximation for the cooling curve, assuming collisional ionization equilibrium. Supernovae are set up both isolated and in associations, in a manner compatible with observations. Once disrupted by the explosions, the disk never returns to its initial state, regardless of the initial vertical distribution of the disk gas, provided enough supernovae occur. Instead a thin HI disk forms in the Galactic plane, and, above and below, a thick inhomogeneous gas disk forms, with scale heights in HI of 500 pc and in HII of 1 kpc. The upper parts of the thick HII disk form the disk-halo interface, where a large scale fountain is set up by hot ionized gas escaping in a turbulent convective flow. The calculations also show the formation of HI clouds in both the disk and halo. These are dynamical objects with a two-phase structure composed of a cold core surrounded by warmer gas. The disk is populated by worms, bubbles, superbubbles and chimneys. Chimneys in the simulations have widths of approximately 120 pc. They inject high temperature gas directly from the Galactic disk into the halo, breaking through the warm neutral and ionized layers that compose the thick disk. Mushroom-shaped structures are also seen in the simulations, as have recently been observed. We identify them as tracers of buoyant flow in the thick disk

  6. Foot roll-over evaluation based on 3D dynamic foot scan.

    Samson, William; Van Hamme, Angèle; Sanchez, Stéphane; Chèze, Laurence; Van Sint Jan, Serge; Feipel, Véronique

    2014-01-01

    Foot roll-over is commonly analyzed to evaluate gait pathologies. The current study utilized a dynamic foot scanner (DFS) to analyze foot roll-over. The right feet of ten healthy subjects were assessed during gait trials with a DFS system integrated into a walkway. A foot sole picture was computed by vertically projecting points from the 3D foot shape which were lower than a threshold height of 15 mm. A 'height' value of these projected points was determined; corresponding to the initial vertical coordinates prior to projection. Similar to pedobarographic analysis, the foot sole picture was segmented into anatomical regions of interest (ROIs) to process mean height (average of height data by ROI) and projected surface (area of the projected foot sole by ROI). Results showed that these variables evolved differently to plantar pressure data previously reported in the literature, mainly due to the specificity of each physical quantity (millimeters vs Pascals). Compared to plantar pressure data arising from surface contact by the foot, the current method takes into account the whole plantar aspect of the foot, including the parts that do not make contact with the support surface. The current approach using height data could contribute to a better understanding of specific aspects of foot motion during walking, such as plantar arch height and the windlass mechanism. Results of this study show the underlying method is reliable. Further investigation is required to validate the DFS measurements within a clinical context, prior to implementation into clinical practice.

  7. 3D Dynamics of the Near-Surface Layer of the Ocean in the Presence of Freshwater Influx

    Dean, C.; Soloviev, A.

    2015-12-01

    Freshwater inflow due to convective rains or river runoff produces lenses of freshened water in the near surface layer of the ocean. These lenses are localized in space and typically involve both salinity and temperature anomalies. Due to significant density anomalies, strong pressure gradients develop, which result in lateral spreading of freshwater lenses in a form resembling gravity currents. Gravity currents inherently involve three-dimensional dynamics. The gravity current head can include the Kelvin-Helmholtz billows with vertical density inversions. In this work, we have conducted a series of numerical experiments using computational fluid dynamics tools. These numerical simulations were designed to elucidate the relationship between vertical mixing and horizontal advection of salinity under various environmental conditions and potential impact on the pollution transport including oil spills. The near-surface data from the field experiments in the Gulf of Mexico during the SCOPE experiment were available for validation of numerical simulations. In particular, we observed a freshwater layer within a few-meter depth range and, in some cases, a density inversion at the edge of the freshwater lens, which is consistent with the results of numerical simulations. In conclusion, we discuss applicability of these results to the interpretation of Aquarius and SMOS sea surface salinity satellite measurements. The results of this study indicate that 3D dynamics of the near-surface layer of the ocean are essential in the presence of freshwater inflow.

  8. Radionuclide transport and uptake in coastal aquatic ecosystems: a comparison of a 3D dynamic model and a compartment model.

    Erichsen, Anders Christian; Konovalenko, Lena; Møhlenberg, Flemming; Closter, Rikke Margrethe; Bradshaw, Clare; Aquilonius, Karin; Kautsky, Ulrik

    2013-05-01

    In safety assessments of underground radioactive waste repositories, understanding radionuclide fate in ecosystems is necessary to determine the impacts of potential releases. Here, the reliability of two mechanistic models (the compartmental K-model and the 3D dynamic D-model) in describing the fate of radionuclides released into a Baltic Sea bay is tested. Both are based on ecosystem models that simulate the cycling of organic matter (carbon). Radionuclide transfer is linked to adsorption and flows of carbon in food chains. Accumulation of Th-230, Cs-135, and Ni-59 in biological compartments was comparable between the models and site measurements despite differences in temporal resolution, biological state variables, and partition coefficients. Both models provided confidence limits for their modeled concentration ratios, an improvement over models that only estimate means. The D-model enables estimates at high spatio-temporal resolution. The K-model, being coarser but faster, allows estimates centuries ahead. Future developments could integrate the two models to take advantage of their respective strengths.

  9. Radionuclide Transport and Uptake in Coastal Aquatic Ecosystems: A Comparison of a 3D Dynamic Model and a Compartment Model

    Erichsen, Anders Christian; Moehlenberg, Flemming; Closter, Rikke Margrethe [Ecological and Environmental Dept., DHI, Hoersholm (Denmark)], E-mail: aer@dhigroup.com; Konovalenko, Lena; Bradshaw, Clare [The Dept. of Ecology, Environment and Plant Sciences, Stockholm Univ., Stockholm (Sweden); Kautsky, Ulrik [Swedish Nuclear Fuel and Waste Management Co. (SKB), Stockholm (Sweden); Aquilonius, Karin [Studsvik Nuclear AB, Nykoeping (Sweden)

    2013-05-15

    In safety assessments of underground radioactive waste repositories, understanding radionuclide fate in ecosystems is necessary to determine the impacts of potential releases. Here, the reliability of two mechanistic models (the compartmental K-model and the 3D dynamic D-model) in describing the fate of radionuclides released into a Baltic Sea bay is tested. Both are based on ecosystem models that simulate the cycling of organic matter (carbon). Radionuclide transfer is linked to adsorption and flows of carbon in food chains. Accumulation of Th-230, Cs-135, and Ni-59 in biological compartments was comparable between the models and site measurements despite differences in temporal resolution, biological state variables, and partition coefficients. Both models provided confidence limits for their modeled concentration ratios, an improvement over models that only estimate means. The D-model enables estimates at high spatio-temporal resolution. The K-model, being coarser but faster, allows estimates centuries ahead. Future developments could integrate the two models to take advantage of their respective strengths.

  10. Constraining the Absolute Orientation of Eta Carinae's Binary Orbit: A 3-D Dynamical Model for the Broad [Fe III] Emission

    Madura, Thomas I; Owocki, Stanley P; Groh, Jose H; Okazaki, Atsuo T; Russell, Christopher M P

    2011-01-01

    We present a three-dimensional (3-D) dynamical model for the broad [Fe III] emission observed in Eta Carinae using the Hubble Space Telescope/Space Telescope Imaging Spectrograph (HST/STIS). This model is based on full 3-D Smoothed Particle Hydrodynamics (SPH) simulations of Eta Car's binary colliding winds. Radiative transfer codes are used to generate synthetic spectro-images of [Fe III] emission line structures at various observed orbital phases and STIS slit position angles (PAs). Through a parameter study that varies the orbital inclination i, the PA {\\theta} that the orbital plane projection of the line-of-sight makes with the apastron side of the semi-major axis, and the PA on the sky of the orbital axis, we are able, for the first time, to tightly constrain the absolute 3-D orientation of the binary orbit. To simultaneously reproduce the blue-shifted emission arcs observed at orbital phase 0.976, STIS slit PA = +38 degrees, and the temporal variations in emission seen at negative slit PAs, the binary ...

  11. Multiview holographic 3D dynamic display by combining a nano-grating patterned phase plate and LCD.

    Wan, Wenqiang; Qiao, Wen; Huang, Wenbin; Zhu, Ming; Ye, Yan; Chen, Xiangyu; Chen, Linsen

    2017-01-23

    Limited by the refreshable data volume of commercial spatial light modulator (SLM), electronic holography can hardly provide satisfactory 3D live video. Here we propose a holography based multiview 3D display by separating the phase information of a lightfield from the amplitude information. In this paper, the phase information was recorded by a 5.5-inch 4-view phase plate with a full coverage of pixelated nano-grating arrays. Because only amplitude information need to be updated, the refreshing data volume in a 3D video display was significantly reduced. A 5.5 inch TFT-LCD with a pixel size of 95 μm was used to modulate the amplitude information of a lightfield at a rate of 20 frames per second. To avoid crosstalk between viewing points, the spatial frequency and orientation of each nano-grating in the phase plate was fine tuned. As a result, the transmission light converged to the viewing points. The angular divergence was measured to be 1.02 degrees (FWHM) by average, slightly larger than the diffraction limit of 0.94 degrees. By refreshing the LCD, a series of animated sequential 3D images were dynamically presented at 4 viewing points. The resolution of each view was 640 × 360. Images for each viewing point were well separated and no ghost images were observed. The resolution of the image and the refreshing rate in the 3D dynamic display can be easily improved by employing another SLM. The recoded 3D videos showed the great potential of the proposed holographic 3D display to be used in mobile electronics.

  12. Constraining the Absolute Orientation of eta Carinae's Binary Orbit: A 3-D Dynamical Model for the Broad [Fe III] Emission

    Madura, T. I.; Gull, T. R.; Owocki, S. P.; Groh, J. H.; Okazaki, A. T.; Russell, C. M. P.

    2011-01-01

    We present a three-dimensional (3-D) dynamical model for the broad [Fe III] emission observed in Eta Carinae using the Hubble Space Telescope/Space Telescope Imaging Spectrograph (HST/STIS). This model is based on full 3-D Smoothed Particle Hydrodynamics (SPH) simulations of Eta Car's binary colliding winds. Radiative transfer codes are used to generate synthetic spectro-images of [Fe III] emission line structures at various observed orbital phases and STIS slit position angles (PAs). Through a parameter study that varies the orbital inclination i, the PA(theta) that the orbital plane projection of the line-of-sight makes with the apastron side of the semi-major axis, and the PA on the sky of the orbital axis, we are able, for the first time, to tightly constrain the absolute 3-D orientation of the binary orbit. To simultaneously reproduce the blue-shifted emission arcs observed at orbital phase 0.976, STIS slit PA = +38deg, and the temporal variations in emission seen at negative slit PAs, the binary needs to have an i approx. = 130deg to 145deg, Theta approx. = -15deg to +30deg, and an orbital axis projected on the sky at a P A approx. = 302deg to 327deg east of north. This represents a system with an orbital axis that is closely aligned with the inferred polar axis of the Homunculus nebula, in 3-D. The companion star, Eta(sub B), thus orbits clockwise on the sky and is on the observer's side of the system at apastron. This orientation has important implications for theories for the formation of the Homunculus and helps lay the groundwork for orbital modeling to determine the stellar masses.

  13. FEM modeling for 3D dynamic analysis of deep-ocean mining pipeline and its experimental verification

    2007-01-01

    3D dynamic analysis models of 1000 m deep-ocean mining pipeline, including steel lift pipe, pump, buffer and flexible hose, were established by finite element method (FEM). The coupling effect of steel lift pipe and flexible hose, and main external loads of pipeline were considered in the models, such as gravity, buoyancy, hydrodynamic forces, internal and external fluid pressures, concentrated suspension buoyancy on the flexible hose, torsional moment and axial force induced by pump working.Some relevant FEM models and solution techniques were developed, according to various 3D transient behaviors of integrated deep-ocean mining pipeline, including towing motions of track-keeping operation and launch process of pipeline. Meanwhile, an experimental verification system in towing water tank that had similar characteristics of designed mining pipeline was developed to verify the accuracy of the FEM models and dynamic simulation. The experiment results show that the experimental records and simulation results of stress of pipe are coincided. Based on the further simulations of 1 000 m deep-ocean mining pipeline, the simulation results show that, to form configuration of a saddle shape, the total concentrated suspension buoyancy of flexible hose should be 95%-105% of the gravity of flexible hose in water, the first suspension point occupies 1/3 of the total buoyancy, and the second suspension point occupies 2/3 of the total buoyancy. When towing velocity of mining system is less than 0.5 m/s, the towing track of buffer is coincided with the setting route of ship on the whole and the configuration of flexible hose is also kept well.

  14. An MRI system for imaging neonates in the NICU: initial feasibility study

    Tkach, Jean A.; Loew, Wolfgang; Pratt, Ron G.; Daniels, Barret R.; Giaquinto, Randy O.; Winter, Patrick M.; Li, Yu; Dumoulin, Charles L. [Cincinnati Children' s Hospital Medical Center, Imaging Research Center, Department of Radiology, Cincinnati, OH (United States); Cincinnati Children' s Hospital Medical Center, Department of Radiology, Cincinnati, OH (United States); Hillman, Noah H.; Jobe, Alan H.; Kallapur, Suhas G.; Merhar, Stephanie L.; Ikegami, Machiko; Whitsett, Jeffrey A. [Perinatal Institute, Cincinnati Children' s Hospital Medical Center, Division of Neonatology and Pulmonary Biology, Cincinnati, OH (United States); Kline-Fath, Beth M. [Cincinnati Children' s Hospital Medical Center, Department of Radiology, Cincinnati, OH (United States)

    2012-11-15

    Transporting premature infants from a neonatal intensive care unit (NICU) to a radiology department for MRI has medical risks and logistical challenges. To develop a small 1.5-T MRI system for neonatal imaging that can be easily installed in the NICU and to evaluate its performance using a sheep model of human prematurity. A 1.5-T MRI system designed for orthopedic use was adapted for neonatal imaging. The system was used for MRI examinations of the brain, chest and abdomen in 12 premature lambs during the first hours of life. Spin-echo, fast spin-echo and gradient-echo MR images were evaluated by two pediatric radiologists. All animals remained physiologically stable throughout the imaging sessions. Animals were imaged at two or three time points. Seven brain MRI examinations were performed in seven different animals, 23 chest examinations in 12 animals and 19 abdominal examinations in 11 animals. At each anatomical location, high-quality images demonstrating good spatial resolution, signal-to-noise ratio and tissue contrast were routinely obtained within 30 min using standard clinical protocols. Our preliminary experience demonstrates the feasibility and potential of the neonatal MRI system to provide state-of-the-art MRI capabilities within the NICU. Advantages include overall reduced cost and site demands, lower acoustic noise, improved ease of access and reduced medical risk to the neonate. (orig.)

  15. An fMRI-compatible force measurement system for the evaluation of the neural correlates of step initiation

    de Lima-Pardini, Andrea Cristina; de Azevedo Neto, Raymundo Machado; Coelho, Daniel Boari; Boffino, Catarina Costa; Shergill, Sukhwinder S.; de Oliveira Souza, Carolina; Brant, Rachael; Barbosa, Egberto Reis; Cardoso, Ellison Fernando; Teixeira, Luis Augusto; Cohen, Rajal G.; Horak, Fay Bahling; Amaro, Edson

    2017-01-01

    Knowledge of brain correlates of postural control is limited by the technical difficulties in performing controlled experiments with currently available neuroimaging methods. Here we present a system that allows the measurement of anticipatory postural adjustment of human legs to be synchronized with the acquisition of functional magnetic resonance imaging data. The device is composed of Magnetic Resonance Imaging (MRI) compatible force sensors able to measure the level of force applied by both feet. We tested the device in a group of healthy young subjects and a group of elderly subjects with Parkinson’s disease using an event-related functional MRI (fMRI) experiment design. In both groups the postural behavior inside the magnetic resonance was correlated to the behavior during gait initiation outside the scanner. The system did not produce noticeable imaging artifacts in the data. Healthy young people showed brain activation patterns coherent with movement planning. Parkinson’s disease patients demonstrated an altered pattern of activation within the motor circuitry. We concluded that this force measurement system is able to index both normal and abnormal preparation for gait initiation within an fMRI experiment. PMID:28230070

  16. An fMRI-compatible force measurement system for the evaluation of the neural correlates of step initiation.

    de Lima-Pardini, Andrea Cristina; de Azevedo Neto, Raymundo Machado; Coelho, Daniel Boari; Boffino, Catarina Costa; Shergill, Sukhwinder S; de Oliveira Souza, Carolina; Brant, Rachael; Barbosa, Egberto Reis; Cardoso, Ellison Fernando; Teixeira, Luis Augusto; Cohen, Rajal G; Horak, Fay Bahling; Amaro, Edson

    2017-02-23

    Knowledge of brain correlates of postural control is limited by the technical difficulties in performing controlled experiments with currently available neuroimaging methods. Here we present a system that allows the measurement of anticipatory postural adjustment of human legs to be synchronized with the acquisition of functional magnetic resonance imaging data. The device is composed of Magnetic Resonance Imaging (MRI) compatible force sensors able to measure the level of force applied by both feet. We tested the device in a group of healthy young subjects and a group of elderly subjects with Parkinson's disease using an event-related functional MRI (fMRI) experiment design. In both groups the postural behavior inside the magnetic resonance was correlated to the behavior during gait initiation outside the scanner. The system did not produce noticeable imaging artifacts in the data. Healthy young people showed brain activation patterns coherent with movement planning. Parkinson's disease patients demonstrated an altered pattern of activation within the motor circuitry. We concluded that this force measurement system is able to index both normal and abnormal preparation for gait initiation within an fMRI experiment.

  17. 7-T MRI in Cerebrovascular Diseases : Challenges to Overcome and Initial Results

    Harteveld, Anita A; van der Kolk, Anja G; Zwanenburg, Jaco J M; Luijten, Peter R; Hendrikse, J

    2016-01-01

    Magnetic resonance imaging (MRI) plays a key role in the investigation of cerebrovascular diseases. Compared with computed tomography (CT) and digital subtraction angiography (DSA), its advantages in diagnosing cerebrovascular pathology include its superior tissue contrast, its ability to visualize

  18. PET/MRI and PET/CT in advanced gynaecological tumours: initial experience and comparison

    Queiroz, Marcelo A.; Schulthess, Gustav von; Veit-Haibach, Patrick [University Hospital Zurich, Department Medical Radiology, Nuclear Medicine, Zurich (Switzerland); University Hospital Zurich, Department Medical Radiology, Diagnostic and Interventional Radiology, Zurich (Switzerland); University of Zurich, Zurich (Switzerland); Kubik-Huch, Rahel A.; Freiwald-Chilla, Bianka [Kantonsspital Baden AG, Department of Radiology, Baden (Switzerland); Hauser, Nik [Kantonsspital Baden AG, Department of Gynaecology, Baden (Switzerland); Froehlich, Johannes M. [Guerbet AG, Zurich (Switzerland)

    2015-08-15

    To compare the diagnostic accuracy of PET/MRI and PET/CT for staging and re-staging advanced gynaecological cancer patients as well as identify the potential benefits of each method in such a population. Twenty-six patients with suspicious or proven advanced gynaecological cancer (12 ovarian, seven cervical, one vulvar and four endometrial tumours, one uterine metastasis, and one primary peritoneal cancer) underwent whole-body imaging with a sequential trimodality PET/CT/MR system. Images were analysed regarding primary tumour detection and delineation, loco-regional lymph node staging, and abdominal/extra-abdominal distant metastasis detection (last only by PET/CT). Eighteen (69.2 %) patients underwent PET/MRI for primary staging and eight patients (30.8 %) for re-staging their gynaecological malignancies. For primary tumour delineation, PET/MRI accuracy was statistically superior to PET/CT (p < 0.001). Among the different types of cancer, PET/MRI presented better tumour delineation mainly for cervical (6/7) and endometrial (2/3) cancers. PET/MRI for local evaluation as well as PET/CT for extra-abdominal metastases had therapeutic consequences in three and one patients, respectively. PET/CT detected 12 extra-abdominal distant metastases in 26 patients. PET/MRI is superior to PET/CT for primary tumour delineation. No differences were found in detection of regional lymph node involvement and abdominal metastases detection. (orig.)

  19. The Application of FLASH-3D Dynamic Contrast-enhanced Technique in Examination of Endometrial Carcinoma%FLASH-3D动态增强技术在子宫内膜癌检查中的应用

    陈富珍; 杜立新; 梁超; 夏军; 李顶夫

    2014-01-01

    目的:探讨FLASH-3D动态增强技术在子宫内膜癌检查中的应用价值及术前分期中的作用。方法前瞻性的对2012年10月-2013年04月间具有完整临床资料及病理组织学证实的子宫内膜癌患者48例,在术前常规MRI检查的基础上,行FLASH-3D动态增强MRI扫描,分析宫壁及肿瘤的MRI动态增强特点,采用双盲法,将FLASH-3D动态增强对子宫内膜癌分期及判断肌层浸润深度的结果,与术后病理组织学FIGO结果对照。结果本组48例中,Ⅰ期34例(Ia22例,Ib12例),Ⅱ期9例,Ⅲ期3例,Ⅳ期2例。FLASH-3D动态增强序列分期准确性为81%(39/48),正确判断深肌层侵犯的敏感性为84%、特异性为90%、准确性为88%、与术后病理组织学结果对照,差异无显著意义(P>0.05)。结论 FLASH-3D动态增强技术在子宫内膜癌早期诊断和术前分期中具有重要作用,能显著提高判断肿瘤肌层浸润深度的准确性,为临床手术方式的选择和术后评估具有指导作用,有望成为女性盆腔肿瘤的常规检查方法。%Objective To investigate the application value and preoperative staging role of FLASH-3D dynamic contrast-enhanced technique in examination of endometrial carcinoma. Methods From October 2012 to April 2013, the prospective study included 48 patients with complete clinical data and pathologically confirmed endometrial carcinoma. After routine MRI examination, the subjects were underwent FLASH-3D (a fast low angle shot technique with three dimensional fat-suppressed angiographic sequences) dynamic contrast-enhanced examination. The dynamic enhancement features of uterine wall and tumors were analyzed respectively. With a double-blind manner,FLASH-3D preoperative staging and findings in assessing myometrial invasion were compared with the postoperative pathological results. Results 48 cases with pathologically-proven endometrial carcinoma were composed of 34 patients in stage I(Ia 22

  20. MRI findings associated with development of incident knee pain over 48 months: data from the osteoarthritis initiative

    Joseph, Gabby B.; Hou, Stephanie W.; Nardo, Lorenzo; Heilmeier, Ursula; Link, Thomas M. [University of California, San Francisco, Department of Radiology and Biomedical Imaging, San Francisco, CA (United States); Nevitt, Michael C.; McCulloch, Charles E. [University of California, San Francisco, Department of Epidemiology and Biostatistics, San Francisco, CA (United States)

    2016-05-15

    The purpose of this nested case-control study was to identify baseline, incident, and progressive MRI findings visible on standard MRI clinical sequences that were associated with development of incident knee pain in subjects at risk for OA over a period of 48 months. We analyzed 60 case knees developing incident pain (WOMAC{sub pain} = 0 at baseline and WOMAC{sub pain} ≥ 5 at 48 months) and 60 control knees (WOMAC{sub pain} = 0 at baseline and WOMAC{sub pain} = 0 at 48 months) from the Osteoarthritis Initiative. 3 T knee MRIs were analyzed using a modified WORMS score (cartilage, meniscus, bone marrow) at baseline and after 48 months. Baseline and longitudinal findings were grouped into logistic regression models and compared using likelihood-ratio tests. For each model that was significant, a stepwise elimination was used to isolate significant MRI findings. One baseline MRI finding and three findings that changed from baseline to 48 months were associated with the development of pain: at baseline, the severity of a cartilage lesion in the medial tibia was associated with incident pain - (odds ratio (OR) for incident pain = 3.05; P = 0.030). Longitudinally, an incident effusion (OR = 9.78; P = 0.005), a progressive cartilage lesion of the patella (OR = 4.59; P = 0.009), and an incident medial meniscus tear (OR = 4.91; P = 0.028) were associated with the development of pain. Our results demonstrate that baseline abnormalities of the medial tibia cartilage as well as an incident joint effusion, progressive patella cartilage defects, and an incident medial meniscus tear over 48 months may be associated with incident knee pain. Clinically, this study helps identify MRI findings that are associated with the development of knee pain. (orig.)

  1. High temporal resolution parametric MRI monitoring of the initial ischemia/reperfusion phase in experimental acute kidney injury.

    Pohlmann, Andreas; Hentschel, Jan; Fechner, Mandy; Hoff, Uwe; Bubalo, Gordana; Arakelyan, Karen; Cantow, Kathleen; Seeliger, Erdmann; Flemming, Bert; Waiczies, Helmar; Waiczies, Sonia; Schunck, Wolf-Hagen; Dragun, Duska; Niendorf, Thoralf

    2013-01-01

    Ischemia/reperfusion (I/R) injury, a consequence of kidney hypoperfusion or temporary interruption of blood flow is a common cause of acute kidney injury (AKI). There is an unmet need to better understand the mechanisms operative during the initial phase of ischemic AKI. Non-invasive in vivo parametric magnetic resonance imaging (MRI) may elucidate spatio-temporal pathophysiological changes in the kidney by monitoring the MR relaxation parameters T2* and T2, which are known to be sensitive to blood oxygenation. The aim of our study was to establish the technical feasibility of fast continuous T2*/T2 mapping throughout renal I/R. MRI was combined with a remotely controlled I/R model and a segmentation model based semi-automated quantitative analysis. This technique enabled the detailed assessment of in vivo changes in all kidney regions during ischemia and early reperfusion. Significant changes in T2* and T2 were observed shortly after induction of renal ischemia and during the initial reperfusion phase. Our study demonstrated for the first time that continuous and high temporal resolution parametric MRI is feasible for in-vivo monitoring and characterization of I/R induced AKI in rats. This technique may help in the identification of the timeline of key events responsible for development of renal damage in hypoperfusion-induced AKI.

  2. High temporal resolution parametric MRI monitoring of the initial ischemia/reperfusion phase in experimental acute kidney injury.

    Andreas Pohlmann

    Full Text Available Ischemia/reperfusion (I/R injury, a consequence of kidney hypoperfusion or temporary interruption of blood flow is a common cause of acute kidney injury (AKI. There is an unmet need to better understand the mechanisms operative during the initial phase of ischemic AKI. Non-invasive in vivo parametric magnetic resonance imaging (MRI may elucidate spatio-temporal pathophysiological changes in the kidney by monitoring the MR relaxation parameters T2* and T2, which are known to be sensitive to blood oxygenation. The aim of our study was to establish the technical feasibility of fast continuous T2*/T2 mapping throughout renal I/R. MRI was combined with a remotely controlled I/R model and a segmentation model based semi-automated quantitative analysis. This technique enabled the detailed assessment of in vivo changes in all kidney regions during ischemia and early reperfusion. Significant changes in T2* and T2 were observed shortly after induction of renal ischemia and during the initial reperfusion phase. Our study demonstrated for the first time that continuous and high temporal resolution parametric MRI is feasible for in-vivo monitoring and characterization of I/R induced AKI in rats. This technique may help in the identification of the timeline of key events responsible for development of renal damage in hypoperfusion-induced AKI.

  3. Stanford type A aortic dissection with closed false lumen: Analysis of prognostic factors at initial CT or MRI

    Matsuoka, Yohjiro; Sakamoto, Ichiro; Ogawa, Yohji; Sueyoshi, Eijun; Hayashi, Kuniaki; Takagi, Masatake [Nagasaki Univ. (Japan). School of Medicine; Narimatsu, Motoharu

    1997-08-01

    Nineteen patients with Stanford type A acute aortic dissection with closed false lumen were reviewed. In the follow-up examinations, ulcerlike projection (ULP) in the ascending aorta (AA) or aortic arch (AR) was identified in 8 of 19 patients. In 5 of these 8 patients, acute cardiac tamponade occurred and 3 of them died. In the other 11 patients, there was no mortality, and only one patient underwent elective surgery. The appearance of ULP in the AA/AR is considered an indication for urgent surgery because it is regarded as a precursor of lethal complications such as cardiac tamponade. The purpose of this study was to investigate predictors of the appearance of ULP in the AA/AR with early imagings (CT or MRI) before the appearance of ULP. The patients were divided into two groups: patients with ULP in the AA/AR (8 patients) and others (11 patients). Initial CT or MRI findings of the thoracic aorta were retrospectively statistically analyzed in each group. Three predictive factors were statistically significant for the appearance of ULP in the AA/AR (diameter of the AA{>=}5 cm, thickness of the false lumen of the AA{>=}1 cm, thickness of the false lumen of the AA{>=} that of the descending aorta). Close attention should be paid, if any of these 3 factors is observed at initial CT or MRI. (author)

  4. Preparation and initial characterization of biodegradable particles containing gadolinium-DTPA contrast agent for enhanced MRI

    Doiron, Amber L.; Chu, Kevin; Ali, Adeel; Brannon-Peppas, Lisa

    2008-01-01

    Accurate imaging of atherosclerosis is a growing necessity for timely treatment of the disease. Magnetic resonance imaging (MRI) is a promising technique for plaque imaging. The goal of this study was to create polymeric particles of a small size with high loading of diethylenetriaminepentaacetic acid gadolinium (III) (Gd-DTPA) and demonstrate their usefulness for MRI. A water-in-oil-in-oil double emulsion solvent evaporation technique was used to encapsulate the MRI agent in a poly(lactide-co-glycolide) (PLGA) or polylactide-poly(ethylene glycol) (PLA-PEG) particle for the purpose of concentrating the agent at an imaging site. PLGA particles with two separate average sizes of 1.83 μm and 920 nm, and PLA-PEG particles with a mean diameter of 952 nm were created. Loading of up to 30 wt % Gd-DTPA was achieved, and in vitro release occurred over 5 h. PLGA particles had highly negative zeta potentials, whereas the particles incorporating PEG had zeta potentials closer to neutral. Cytotoxicity of the particles on human umbilical vein endothelial cells (HUVEC) was shown to be minimal. The ability of the polymeric contrast agent formulation to create contrast was similar to that of Gd-DTPA alone. These results demonstrate the possible utility of the contrast agent-loaded polymeric particles for plaque detection with MRI. PMID:18796605

  5. Contrast-enhanced 3D MRI of lung perfusion in children with cystic fibrosis - initial results

    Eichinger, Monika; Puderbach, Michael; Zuna, Ivan; Kauczor, Hans-Ulrich [Deutsches Krebsforschungszentrum (DKFZ), Department of Radiology (E010), Heidelberg (Germany); Fink, Christian [Institut fuer Klinische Radiologie, Klinikum der LMU Grosshadern, Department of Radiology, Muenchen (Germany); Gahr, Julie; Mueller, Frank-Michael [Universitaetskinderklinik III Heidelberg, Department of Pediatric Pulmonology, Cystic Fibrosis Centre and Infectious Diseases, Heidelberg (Germany); Ley, Sebastian [Deutsches Krebsforschungszentrum (DKFZ), Department of Radiology (E010), Heidelberg (Germany); Universitaetskinderklinik Heidelberg, Department of Pediatric Radiology, Heidelberg (Germany); Plathow, Christian [Eberhard-Karls University, Department of Diagnostic Radiology, Tuebingen (Germany); Tuengerthal, Siegfried [Thoraxklinik am Universitaetsklinikum Heidelberg, Department of Radiology, Heidelberg (Germany)

    2006-10-15

    This paper is a feasibility study of magnetic resonance imaging (MRI) of lung perfusion in children with cystic fibrosis (CF) using contrast-enhanced 3D MRI. Correlation assessment of perfusion changes with structural abnormalities. Eleven CF patients (9 f, 2 m; median age 16 years) were examined at 1.5 T. Morphology: HASTE coronal, transversal (TR/TE/{alpha}/ST: 600 ms/28 ms/180 /6 mm), breath-hold 18 s. Perfusion: Time-resolved 3D GRE pulse sequence (FLASH, TE/TR/{alpha}: 0.8/1.9 ms/40 ), parallel imaging (GRAPPA, PAT 2). Twenty-five data sets were acquired after intravenous injection of 0.1 mmol/kg body weight of gadodiamide, 3-5 ml/s. A total of 198 lung segments were analyzed by two radiologists in consensus and scored for morphological and perfusion changes. Statistical analysis was performed by Mantel-Haenszel chi-square test. Results showed that perfusion defects were observed in all patients and present in 80% of upper, and 39% of lower lobes. Normal lung parenchyma showed homogeneous perfusion (86%, P<0.0001). Severe morphological changes led to perfusion defects (97%, P<0.0001). Segments with moderate morphological changes showed normal (53%) or impaired perfusion (47%). In conclusion, pulmonary perfusion is easy to judge in segments with normal parenchyma or severe changes. In moderately damaged segments, MRI of lung perfusion may help to better assess actual functional impairment. Contrast-enhanced 3D MRI of lung perfusion has the potential for early vascular functional assessment and therapy control in CF patients. (orig.)

  6. Gadoxetic Acid (Gd-EOB-DTPA)-Enhanced MRI versus Gadobenate Dimeglumine (Gd-BOPTA)-Enhanced MRI for Preoperatively Detecting Hepatocellular Carcinoma: an Initial Experience

    Park, Yu Lri; Kim, Seong Hyun; Kim, Seung Hoon; Choi, Dong Il; Lee, Won Jae; Kim, Hee Jung; Koo, Ji Hyun; Lim, Hyo Keun [Samsung Medical Center, Seoul (Korea, Republic of); Jeon, Yong Hwan [Kangwon National University Hospital, Chuncheon (Korea, Republic of); Lee, Jong Mee; Kim, Min Ju [Korea University College of Medicine, Korea University Guro Hospital, Seoul (Korea, Republic of)

    2010-08-15

    This study was designed to compare the diagnostic performance of gadoxetic acid-enhanced magnetic resonance imaging (MRI) with gadobenate dimeglumine-enhanced MRI for preoperatively detecting hepatocellular carcinoma (HCC). Eighteen consecutive patients (17 men and one woman, age range: 31-73 years) with 22 HCCs underwent examinations with gadoxetic acid enhanced MRI and gadobenate dimeglumine-enhanced MRI on a 3.0-Tesla unit. The diagnosis of HCC was established after surgical resection and pathological conformation. Three observers independently reviewed each MR image in a random order on a tumor-by-tumor basis. The diagnostic accuracy of these techniques for the detection of HCC was assessed by performing an alternative free-response receiver operating characteristic (ROC) analysis. The sensitivity and positive predictive values were evaluated. The average value of the area under the ROC curve (Az) for gadoxetic acid enhanced MRI (0.887) was not significantly different from the Az (0.899) for gadobenate dimeglumine-enhanced MRI (p > 0.05). The overall sensitivities of gadoxetic acid enhanced MRI and gadobenate dimeglumine-enhanced MRI were 80% and 83%, respectively, with no significant difference (p > 0.05). The differences of the positive predictive values for the two contrast agents for each observer were not statistically significant (p > 0.05). The diagnostic performance of gadoxetic acid-enhanced MRI and gadobenate dimeglumine-enhanced MRI for preoperatively detecting HCC is quite similar

  7. MRI-Guided Intervention for Breast Lesions Using the Freehand Technique in a 3.0-T Closed-Bore MRI Scanner: Feasibility and Initial Results

    Choi, Hye Young [Department of Radiology, Gyeongsang National University Hospital, Jinju 660-702 (Korea, Republic of); Kim, Sun Mi; Jang, Mijung; Yun, Bo La [Department of Radiology, Seoul National University Bundang Hospital, Seongnam 463-707 (Korea, Republic of); Kim, Sung-Won; Kang, Eunyoung [Department of Surgery, Seoul National University Bundang Hospital, Seongnam 463-707 (Korea, Republic of); Park, So Yeon [Department of Pathology, Seoul National University Bundang Hospital, Seongnam 463-707 (Korea, Republic of); Moon, Woo Kyung [Department of Radiology, Seoul National University College of Medicine, Seoul National University Hospital, Seoul 110-744 (Korea, Republic of); Ko, Eun Sook [Department of Radiology, Samsung Medical Center, Seoul 135-710 (Korea, Republic of)

    2013-07-01

    To report the feasibility of magnetic resonance imaging (MRI)-guided intervention for diagnosing suspicious breast lesions detectable by MRI only, using the freehand technique with a 3.0-T closed-bore MRI scanner. Five women with 5 consecutive MRI-only breast lesions underwent MRI-guided intervention: 3 underwent MRI-guided needle localization and 2, MRI-guided vacuum-assisted biopsy. The interventions were performed in a 3.0-T closed-bore MRI system using a dedicated phased-array breast coil with the patients in the prone position; the freehand technique was used. Technical success and histopathologic outcome were analyzed. MRI showed that four lesions were masses (mean size, 11.5 mm; range, 7-18 mm); and 1, a nonmass-like enhancement (maximum diameter, 21 mm). The locations of the lesions with respect to the breast with index cancer were as follows: different quadrant, same breast - 3 cases; same quadrant, same breast - 1 case; and contralateral breast - 1 case. Histopathologic evaluation of the lesions treated with needle localization disclosed perilobular hemangioma, fibrocystic change, and fibroadenomatous change. The lesions treated with vacuum-assisted biopsy demonstrated a radial scar and atypical apocrine hyperplasia. Follow-up MRI after 2-7 months (mean, 4.6 months) confirmed complete lesion removal in all cases. MRI-guided intervention for breast lesions using the freehand technique with a 3.0-T closed-bore MRI scanner is feasible and accurate for diagnosing MRI-only lesions.

  8. 3D Dynamic Rupture Simulation Across a Complex Fault System: the Mw7.0, 2010, Haiti Earthquake

    Douilly, R.; Aochi, H.; Calais, E.; Freed, A. M.

    2013-12-01

    Earthquakes ruptures sometimes take place on a secondary fault and surprisingly do not activate an adjacent major one. The 1989 Loma Prieta earthquake is a classic case where rupture occurred on a blind thrust while the adjacent San Andreas Fault was not triggered during the process. Similar to Loma Prieta, the Mw7.0, January 12 2010, Haiti earthquake also ruptured a secondary blind thrust, the Léogâne fault, adjacent to the main plate boundary, the Enriquillo Plantain Garden Fault, which did not rupture during this event. Aftershock relocalizations delineate the Léogâne rupture with two north dipping segments with slightly different dip, where the easternmost segment had mostly dip-slip motion and the westernmost one had mostly strike-slip motion. In addition, an offshore south dipping structure inferred from the aftershocks to the west of the rupture zone coincides with the offshore Trois Baies reverse fault, a region of increase in Coulomb stress increase. In this study, we investigate the rupture dynamics of the Haiti earthquake in a complex fault system of multiple segments identified by the aftershock relocations. We suppose a background stress regime that is consistent with the type of motion of each fault and with the regional tectonic regime. We initiate a nucleation on the east segment of the Léogâne fault by defining a circular region with a 2 km radius where shear stress is slightly greater than the yield stress. By varying friction on faults and background stress, we find a range of plausible scenarios. In the absence of near-field seismic records of the event, we score the different models against the static deformation field derived from GPS and InSAR at the surface. All the plausible simulations show that the rupture propagates from the eastern to the western segment along the Léogâne fault, but not on the Enriquillo fault nor on the Trois Baies fault. The best-fit simulation shows a significant increase of shear stresses on the Trois Baies

  9. Myocardial delayed contrast enhancement in patients with arterial hypertension: Initial results of cardiac MRI

    Andersen, Kjel [Institute of Diagnostic Radiology, University Hospital Duesseldorf, Moorenstr. 5, 40225 Duesseldorf (Germany)], E-mail: kjel_andersen@web.de; Hennersdorf, Marcus [Department of Cardiology, University Hospital Duesseldorf, Moorenstr. 5, 40225 Duesseldorf (Germany)], E-mail: hennersdorf@med.uni-duesseldorf.de; Cohnen, Mathias [Institute of Diagnostic Radiology, University Hospital Duesseldorf, Moorenstr. 5, 40225 Duesseldorf (Germany)], E-mail: cohnen@med.uni-duesseldorf.de; Blondin, Dirk [Institute of Diagnostic Radiology, University Hospital Duesseldorf, Moorenstr. 5, 40225 Duesseldorf (Germany)], E-mail: blondin@med.uni-duesseldorf.de; Moedder, Ulrich [Institute of Diagnostic Radiology, University Hospital Duesseldorf, Moorenstr. 5, 40225 Duesseldorf (Germany)], E-mail: moedder@uni-duesseldorf.de; Poll, Ludger W. [Institute of Diagnostic Radiology, University Hospital Duesseldorf, Moorenstr. 5, 40225 Duesseldorf (Germany)], E-mail: poll@gmx.de

    2009-07-15

    Purpose: In arterial hypertension left ventricular hypertrophy comprises myocyte hypertrophy, interstitial fibrosis and structural alterations of the coronary microcirculation. MRI enables the detection of myocardial fibrosis, infarction and scar tissue by delayed enhancement (DE) after contrast media application. Aim of this study was to investigate patients with arterial hypertension but without known coronary disease or previous myocardial infarction to detect areas of DE. Methods and material: Twenty patients with arterial hypertension with clinical symptoms of myocardial ischemia, but without history of myocardial infarction and normal coronary arteries during coronary angiography were investigated on a 1.0 T superconducting magnet (Gyroscan T10-NT, Intera Release 8.0, Philips). Fast gradient-echo cine sequences and T2-weighted STIR-sequences were acquired. Fifteen minutes after injection of Gadobenate dimeglumine inversion recovery gradient-echo sequences were performed for detection of myocardial DE. Presence or absence of DE on MRI was correlated with clinical data and the results of echocardiography and electrocardiography, respectively. Results: Nine of 20 patients showed DE in the interventricular septum and the anteroseptal left ventricular wall. In 6 patients, DE was localized intramurally and in 3 patients subendocardially. There was a significant correlation between myocardial DE and ST-segment depressions during exercise and between DE and left-ventricular enddiastolic pressure. Patients with intermittent atrial fibrillation showed a myocardial DE more often than patients without atrial fibrillation. Conclusion: In our series, 45% of patients with arterial hypertension showed DE on cardiac MRI. In this clinical setting, delayed enhancement may be due to coronary microangiopathy. The more intramurally localization of DE, however, rather indicates myocardial interstitial fibrosis.

  10. Noninvasive measurement of liver iron concentration at MRI in children with acute leukemia: initial results

    Vag, Tibor; Krumbein, Ines; Reichenbach, Juergen R.; Lopatta, Eric; Stenzel, Martin; Kaiser, Werner A.; Mentzel, Hans-Joachim [Friedrich Schiller University Jena, Institute of Diagnostic and Interventional Radiology, Jena (Germany); Kentouche, Karim; Beck, James [Friedrich Schiller University Jena, Department of Pediatrics, Jena (Germany); Renz, Diane M. [Charite University Medicine Berlin, Department of Radiology, Campus Virchow Clinic, Berlin (Germany)

    2011-08-15

    Routine assessment of body iron load in patients with acute leukemia is usually done by serum ferritin (SF) assay; however, its sensitivity is impaired by different conditions including inflammation and malignancy. To estimate, using MRI, the extent of liver iron overload in children with acute leukemia and receiving blood transfusions, and to examine the association between the degree of hepatic iron overload and clinical parameters including SF and the transfusion iron load (TIL). A total of 25 MRI measurements of the liver were performed in 15 children with acute leukemia (mean age 9.75 years) using gradient-echo sequences. Signal intensity ratios between the liver and the vertebral muscle (L/M ratio) were calculated and compared with SF-levels. TIL was estimated from the cumulative blood volume received, assuming an amount of 200 mg iron per transfused red blood cell unit. Statistical analysis revealed good correlation between the L/M SI ratio and TIL (r = -0.67, P = 0.002, 95% confidence interval CI = -0.83 to -0.34) in patients with acute leukemia as well as between L/M SI ratio and SF (r = -0.76, P = 0.0003, 95% CI = -0.89 to -0.52). SF may reliably reflect liver iron stores as a routine marker in patients suffering from acute leukemia. (orig.)

  11. MR guidance and thermometry of percutaneous laser disc decompression in open MRI: an initial clinical investigation

    Streitparth, Florian; Walter, Thula; Bucourt, Maximilian de; Freyhardt, Patrick; Maurer, Martin; Renz, Diane; Gebauer, Bernhard; Hamm, Bernd; Teichgraeber, Ulf K.M. [Charite, Humboldt-University Medical School, Department of Radiology, Berlin (Germany); Hartwig, Tony; Putzier, Michael; Strube, Patrick [Charite, Humboldt-University, Center for Musculoskeletal Surgery, Berlin (Germany); Bretschneider, Tina [University of Magdeburg, Department of Radiology, Magdeburg (Germany)

    2013-10-15

    To assess the feasibility, safety and efficacy of real-time MR guidance and thermometry of percutaneous laser disc decompression (PLDD). Twenty-four discs in 22 patients with chronic low-back and radicular pain were treated by PLDD using open 1.0-T magnetic-resonance imaging (MRI). A fluoroscopic proton-density-weighted turbo spin-echo (PDw TSE) sequence was used to position the laser fibre. Non-spoiled gradient-echo (GRE) sequences were employed for real-time thermal monitoring based on proton resonance frequency (PRF). Radicular pain was assessed over 6 months with a numerical rating scale (NRS). PLDD was technically successful in all cases, with adequate image quality for laser positioning. The PRF-based real-time temperature monitoring was found to be feasible in practice. After 6 months, 21 % reported complete remission of radicular pain, 63 % at least great pain relief and 74 % at least mild relief. We found a significant decrease in the NRS score between the pre-intervention and the 6-month follow-up assessment (P < 0.001). No major complications occurred; the single adverse event recorded, moderate motor impairment, resolved. Real-time MR guidance and PRF-based thermometry of PLDD in the lumbar spine under open 1.0-T MRI appears feasible, safe and effective and may pave the way to more precise operating procedures. (orig.)

  12. RM de cuerpo entero, experiencia inicial Whole body MRI, initial experience

    Ezequiel Rombolá

    2008-09-01

    Full Text Available Objetivo: Exponer y compartir nuestra experiencia en resonancia magnética de cuerpo entero (RMCE. Material y métodos: Se realizó estudio prospectivo entre octubre de 2005 y mayo de 2007 sobre 165 RMCE. Edad de los pacientes: 21 y 85 años, media de 51,64. Se utilizó equipo de 1,5 Tesla de campo magnético y tabla deslizable. El protocolo de estudio estuvo integrado por cortes coronales multicontraste (T1, T2 y STIR, axiales y sagitales en T2. Resultados: Se obtuvieron 140 (84,84 % estudios con hallazgos relevantes y 25 (15,15 % sin alteraciones. Se halló predominancia de enfermedades degenerativas articulares del esqueleto axial en 94 pacientes (56,96% sin diferencias significativas entre sexos. Trece pacientes realizaron controles oncológicos demostrándose diseminación a distancia en 6 estudios. En 1 examen se registró la distribución de polimiositis. Conclusiones: La RMCE no representa solamente una innovadora herramienta diagnóstica, sino también ostenta el potencial de competir con metodologías preexistentes en aplicaciones oncológicas y no oncológicas. La sensibilidad y especificidad del método están probadas, pero su aplicación se encuentra limitada por el alto costo y la falta de inclusión en protocolos diagnósticos de estadificación tumoral.Objective: To expose and share our experience in whole-body MRI. Material and methods: A prospective study of 165 whole-body MRI was made from october 2005 to may 2007. The age range was between 21 to 85 years old, with a mean age of 51, 64. A 1.5 Tesla MRI scan was utilized with a table-top movement. Multicontrast coronal scans (T1, T2 and STIR, sagittal and axial T2 compose the study protocol. Results: 140 (84,84 % scans with relevant results and 25 (15,15 % without abnormalities were found. The axial skeletal articular degenerative disease prevalence on 94 (56,96 % cases, without significant difference. Six MRI scans showed secondary dissemination of the oncology disease in a

  13. The predictability of T3 disease in staging MRI following prostate biopsy decreases in patients with high initial PSA and Gleason score

    Young Hwii Ko; Deuk Jae Sung; Sung Gu Kang; Seok Ho Kang; Jeong Gu Lee; Je Jong Kim; Jun Cheon

    2011-01-01

    To obtain improved accuracy in predicting extracapsular extension (ECE) and seminal vesicle invasion (SVI), we evaluated the variables affecting the predictability of staging magnetic resonance imaging (MRI, phased-array coil) and estimated their impact on accuracy between preoperative MRI staging and histological outcome. A total of 121 patients with localized or locally advanced prostate cancer who underwent robotic radical prostatectomy (RALP) were included. Following transrectal biopsy, all enrolled patients had undergone MRI for staging work-up. After RALP, only 43.8% (53/121) of the patients were matched with the MRI predicted stage. Compared to the matched group in the prediction of ECE, the unmatched group had significantly higher initial prostate-specific antigen (PSA, 12.8 ng ml-1 versus 8.1 ng ml-1, P=0.048). In the prediction of SVI, initial PSA (8.1 ng ml-1 versus 17.3 ng ml-1, P=0.009) and biopsy Gleason score (6.5 versus 7.6, P=0.035) were significantly higher in the unmatched group. When applying clinical cutoffs of initial PSA of 10 and 20 ng ml-1, the accuracy of MRI in the prediction of ECE was decreased in the group with PSA over 20 ng ml-1 (75.6,64.5 and 37.5%, P=0.01), and this group had significantly decreased accuracy of MRI in the prediction of SVI (91.5,77.4 and 37.5%, P<0.01). Applying the clinical cutoff of a Gleason score of 7, the accuracy of MRI in the prediction of SVI was decreased in the higher Gleason score group (93.9,82.1 and 62.9%, P=0.01). Thus, for these patient groups, to obtain margin negativity during radical prostatectomy, operative findings, rather than post-biopsy MRI images, may provide substantial information, implying a clinical advantage in conducting MRI before prostate biopsy.

  14. MRI-based motion correction of thoracic PET: initial comparison of acquisition protocols and correction strategies suitable for simultaneous PET/MRI systems

    Dikaios, Nikolaos; Fryer, Tim D. [University of Cambridge, Wolfson Brain Imaging Centre, Department of Clinical Neurosciences, Cambridge (United Kingdom); Izquierdo-Garcia, David; Mani, Venkatesh; Fayad, Zahi A. [Mount Sinai School of Medicine, Imaging Science Laboratories, Translational and Molecular Imaging Institute, Department of Radiology, New York, NY (United States); Graves, Martin J. [University of Cambridge, Department of Radiology, Cambridge (United Kingdom)

    2012-02-15

    Magnetic resonance imaging (MRI) acquired on equipment capable of simultaneous MRI and positron emission tomography (PET) could potentially provide the gold standard method for motion correction of PET. To assess the latter, in this study we compared fast 2D and 3D MRI of the torso and used deformation parameters from real MRI data to correct simulated PET data for respiratory motion. PET sinogram data were simulated using SimSET from a 4D pseudo-PET image series created by segmenting MR images acquired over a respiratory cycle. Motion-corrected PET images were produced using post-reconstruction registration (PRR) and motion-compensated image reconstruction (MCIR). MRI-based motion correction improved PET image quality at the lung-liver and lung-spleen boundaries and in the heart but little improvement was obtained where MRI contrast was low. The root mean square error in SUV units per voxel compared to a motion-free image was reduced from 0.0271 (no motion correction) to 0.0264 (PRR) and 0.0250 (MCIR). Motion correction using MRI can improve thoracic PET images but there are limitations due to the quality of fast MRI. (orig.)

  15. Breast segmentation in MRI using Poisson surface reconstruction initialized with random forest edge detection

    Martel, Anne L.; Gallego-Ortiz, Cristina; Lu, YingLi

    2016-03-01

    Segmentation of breast tissue in MRI images is an important pre-processing step for many applications. We present a new method that uses a random forest classifier to identify candidate edges in the image and then applies a Poisson reconstruction step to define a 3D surface based on the detected edge points. Using a leave one patient out cross validation we achieve a Dice overlap score of 0.96 +/- 0.02 for T1 weighted non-fat suppressed images in 8 patients. In a second dataset of 332 images acquired using a Dixon sequence, which was not used in training the random classifier, the mean Dice score was 0.90 +/- 0.03. Using this approach we have achieved accurate, robust segmentation results using a very small training set.

  16. A finite difference method for the design of gradient coils in MRI--an initial framework.

    Zhu, Minhua; Xia, Ling; Liu, Feng; Zhu, Jianfeng; Kang, Liyi; Crozier, Stuart

    2012-09-01

    This paper proposes a finite-difference (FD)-based method for the design of gradient coils in MRI. The design method first uses the FD approximation to describe the continuous current density of the coil space and then employs the stream function method to extract the coil patterns. During the numerical implementation, a linear equation is constructed and solved using a regularization scheme. The algorithm details have been exemplified through biplanar and cylindrical gradient coil design examples. The design method can be applied to unusual coil designs such as ultrashort or dedicated gradient coils. The proposed gradient coil design scheme can be integrated into a FD-based electromagnetic framework, which can then provide a unified computational framework for gradient and RF design and patient-field interactions.

  17. Functional connectivity MRI and post-operative language performance in temporal lobe epilepsy: initial experience.

    Pravatà, Emanuele; Sestieri, Carlo; Colicchio, Gabriella; Colosimo, Cesare; Romani, Gian Luca; Caulo, Massimo

    2014-04-01

    Anterior temporal lobectomy is an effective treatment for drug-resistant epilepsy of temporal origin, although new language impairment may develop after surgery. Since correlations between functional connectivity (FC) MRI of the language network and verbal-IQ performance before surgery have recently been reported, we investigated the existence of correlations between the preoperative FC of the language network and post-operative verbal-IQ decline. FC between nodes of the language network of the two hemispheres (Interhemispheric-FC) and within nodes of the left hemisphere (LH-FC) and language lateralization indexes were estimated in five right-handed patients with non-tumoral left temporal lobe epilepsy undergoing anterior temporal lobectomy. Correlations between preoperative FC measures and lateralization indexes, and the post-operative (12 months) neuropsychological verbal-IQ decline were investigated. Verbal-IQ decline was inversely correlated with the degree of left lateralization and directly correlated with the strength of Interhemispheric-FC. No significant correlation was found between LH-FC and post-operative verbal-IQ change. The results from this limited number of patients suggest that a stronger preoperative connectivity between homologue regions, associated with the absence of a definite hemispheric lateralization, appears to be an unfavorable prognostic biomarker.

  18. GEM/POPs: a global 3-D dynamic model for semi-volatile persistent organic pollutants – Part 2: Global transports and budgets of PCBs

    L. A. Barrie

    2007-03-01

    Full Text Available Global transports and budgets of three PCBs were investigated with a 3-D dynamic model for semi-volatile persistent organic pollutants – GEM/POPs. Dominant pathways were identified for PCB transports in the atmosphere with a peak transport flux below 8 km and 14 km for gaseous and particulate PCB28, 4 km and 6 km for gaseous and particulate PCB180. The inter-continental transports of PCBs in the Northern Hemisphere (NH are dominated in the zonal direction with their route changes seasonally regulated by the variation of westerly jet. The transport pathways from Europe and North Atlantic to the Arctic contributed the most PCBs over there. Inter-hemispheric transports of PCBs originated from the regions of Europe, Asia and North America in three different flow-paths, accompanying with easterly jet, Asian monsoon winds and trade winds. PCBs from the Southern Hemisphere (SH could export into the NH. According to the PCB emissions of year 2000, Europe, North America and Asia are the three largest sources of the three PCBs, contributing to the global background concentrations in the atmosphere and soil and water. Globally, PCB28 in soil and water has become a comparable source to the anthropogenic emissions while heavier PCBs such as PCB153 and 180 are still transporting into soil and water. It is found that lighter PCBs have more long range transport potentials than their heavier counter-parts in the atmosphere.

  19. Predictive value of semi-quantitative MRI-based scoring systems for future knee replacement: data from the osteoarthritis initiative

    Hafezi-Nejad, Nima; Eng, John; Demehri, Shadpour [Johns Hopkins University School of Medicine, Musculoskeletal Radiology, Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, MD (United States); Zikria, Bashir [Johns Hopkins University, Department of Orthopedic Surgery, Baltimore, MD (United States); Carrino, John A. [Hospital for Special Surgery, Department of Radiology and Imaging, New York, NY (United States)

    2015-11-15

    To evaluate, in a confirmatory fashion, whether baseline and change from baseline to 24-month follow-up in cartilage damage, bone marrow lesions and meniscal damage are predictors of knee replacement (KR) in subjects with a high risk of osteoarthritis (OA), independent of the level of physical activity, symptom severity and radiographic abnormalities. Data from the Osteoarthritis Initiative's (OAI) baseline and 24-month follow-up knee MRIs of 115 patients (age range: 45-78 years; 48 % female; BMI: 20.9-48.7) were analyzed. Cartilage, bone marrow and menisci were semi-quantitatively scored according to the Whole-Organ Magnetic Resonance Imaging Score (WORMS) and Boston-Leeds Osteoarthritis Knee Score (BLOKS) systems in all compartments. Baseline and 24-month interval changes in structural tissue damage assessed by BLOKS and WORMS were used as predictors of KR independent of clinical and radiographic parameters using Cox hazard analysis. Adjustments were performed for age, gender, BMI and physical activity (Physical Activity Scale for the Elderly: PASE), Western Ontario and McMaster Questionnaire (WOMAC) total score and radiographic Kellgren-Lawrence (KL) score. BLOKS and WORMS baseline cartilage scores were predictors of KR independent of the PASE, WOMAC and KL score. One score increase in the average baseline BLOKS full-thickness cartilage defect score was associated with a [hazard ratio (95 % CI)] 13.55 (3.61-50.89) times greater risk of KR independent of the PASE, WOMAC and KL score. Net reclassification improvements (NRIs) of the additional evaluation of 24-month follow-up MRI scores and assessment of changes were not significant for prediction of KR (NRI range: - 7.23 - 24.8 %). The BLOKS cartilage score for full-thickness cartilage defects had the highest hazard for KR. Follow-up MRI changes in structural tissue damage, detected by BLOKS and WORMS cartilage, bone marrow or meniscus scores (up to 24 months) had no significant predictive value in addition

  20. Study of 3-D Dynamic Roughness Effects on Flow Over a NACA 0012 Airfoil Using Large Eddy Simulations at Low Reynolds Numbers

    Guda, Venkata Subba Sai Satish

    There have been several advancements in the aerospace industry in areas of design such as aerodynamics, designs, controls and propulsion; all aimed at one common goal i.e. increasing efficiency --range and scope of operation with lesser fuel consumption. Several methods of flow control have been tried. Some were successful, some failed and many were termed as impractical. The low Reynolds number regime of 104 - 105 is a very interesting range. Flow physics in this range are quite different than those of higher Reynolds number range. Mid and high altitude UAV's, MAV's, sailplanes, jet engine fan blades, inboard helicopter rotor blades and wind turbine rotors are some of the aerodynamic applications that fall in this range. The current study deals with using dynamic roughness as a means of flow control over a NACA 0012 airfoil at low Reynolds numbers. Dynamic 3-D surface roughness elements on an airfoil placed near the leading edge aim at increasing the efficiency by suppressing the effects of leading edge separation like leading edge stall by delaying or totally eliminating flow separation. A numerical study of the above method has been carried out by means of a Large Eddy Simulation, a mathematical model for turbulence in Computational Fluid Dynamics, owing to the highly unsteady nature of the flow. A user defined function has been developed for the 3-D dynamic roughness element motion. Results from simulations have been compared to those from experimental PIV data. Large eddy simulations have relatively well captured the leading edge stall. For the clean cases, i.e. with the DR not actuated, the LES was able to reproduce experimental results in a reasonable fashion. However DR simulation results show that it fails to reattach the flow and suppress flow separation compared to experiments. Several novel techniques of grid design and hump creation are introduced through this study.

  1. Ischemic Stroke of the Artery of Percheron with Normal Initial MRI: A Case Report

    Guillaume Cassourret

    2010-01-01

    Full Text Available The artery of Percheron is a solitary trunk representing an uncommon anatomic variant that provides bilateral arterial supply to the paramedian thalami and the rostral midbrain. Occlusion of this artery results in bilateral thalamic and mesencephalic infarctions. The clinical diagnosis is difficult because the complex anatomy causes large clinical variability. We report a case of a comatose patient with normal early head-computed tomography and magnetic resonance imaging. A bilateral paramedian thalamic infarct due to an occlusion of the artery of Percheron was revealed two days later by a new head computed tomography. To our knowledge, this is the first report in the literature of a symptomatic patient presenting an acute Percheron stroke with normal early brain magnetic resonance imaging. Our case indicates that a normal initial magnetic resonance imaging cannot formally eliminate the diagnosis of acute stroke of the artery of Percheron. We discuss the causes of noncontributive brain magnetic resonance imaging at the onset of this acute Percheron stroke and the alternative diagnosis and therapy methods.

  2. {sup 18}F-FDG PET and MRS of the early stages of subacute sclerosing panencephalitis in a child with a normal initial MRI

    Seo, Yeong-Seon; Jung, Da-Eun [Ajou University School of Medicine, Department of Pediatrics, Suwon, Kyungki-do (Korea, Republic of); Kim, Ho-Sung [Ajou University School of Medicine, Department of Radiology, Suwon, Kyungki-do (Korea, Republic of)

    2010-11-15

    In subacute sclerosing panencephalitis (SSPE), conventional MRI findings have been reported. However, in the early clinical stages, imaging studies can appear normal. Moreover, with no history of infant measles infection, the diagnosis of SSPE can only be arrived at after extensive investigation that must eliminate a number of neurodegenerative diseases. We report here on {sup 18} F-fluorodeoxyglucose positron emission tomography ({sup 18}F-FDG PET) and magnetic resonance spectroscopy (MRS) findings in a 14-year-old girl with a normal initial MRI who had not contracted measles. Although {sup 18} F-FDG PET and MRS are not specific or diagnostic for SSPE, these techniques can demonstrate substantial metabolic impairments when MRI findings show no obvious abnormalities, as is often the case in the early stages of this disease. (orig.)

  3. {sup 18}F-FDOPA PET/MRI fusion in patients with primary/recurrent gliomas: Initial experience

    Ledezma, Carlos J. [Department of Radiological Sciences, David Geffen School of Medicine, University of California Los Angeles, 10833 Le Conte Avenue, Los Angeles, CA 90095 (United States)], E-mail: ledezmacjl@gmail.com; Chen, Wei [Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California Los Angeles, 10833 Le Conte Avenue, Los Angeles, CA 90095 (United States)], E-mail: weichen@mednet.ucla.edu; Sai, Victor [School of Medicine, David Geffen School of Medicine, University of California Los Angeles, 10833 Le Conte Avenue, Los Angeles, CA 90095 (United States)], E-mail: vsai@ucla.edu; Freitas, Bonnie [Department of Radiological Sciences, David Geffen School of Medicine, University of California Los Angeles, 10833 Le Conte Avenue, Los Angeles, CA 90095 (United States)], E-mail: bfreitas@mednet.ucla.edu; Cloughesy, Tim [Department of Neurology, David Geffen School of Medicine, University of California Los Angeles, 10833 Le Conte Avenue, Los Angeles, CA 90095 (United States)], E-mail: tcloughe@ucla.edu; Czernin, Johannes [Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California Los Angeles, 10833 Le Conte Avenue, Los Angeles, CA 90095 (United States)], E-mail: jczernin@mednet.ucla.edu; Pope, Whitney [Department of Radiological Sciences, David Geffen School of Medicine, University of California Los Angeles, 10833 Le Conte Avenue, Los Angeles, CA 90095 (United States)], E-mail: wpope@mednet.ucla.edu

    2009-08-15

    Background and purpose: {sup 18}F-FDOPA PET demonstrates higher sensitivity and specificity for gliomas than traditional [{sup 18}F] FDG PET imaging. However, PET provides limited anatomic localization. The purpose of this study was to determine whether {sup 18}F-FDOPA PET/MRI fusion can provide precise anatomic localization of abnormal tracer uptake and how this activity corresponds to MR signal abnormality. Methods: Two groups of patients were analyzed. Group I consisted of 21 patients who underwent {sup 18}F-FDOPA PET and MRI followed by craniotomy for tumor resection. Group II consisted of 70 patients with a pathological diagnosis of glioma that had {sup 18}F-FDOPA PET and MRI but lacked additional pathologic follow-up. Fused {sup 18}F-FDOPA PET and MRI images were analyzed for concordance and correlated with histopathologic data. Results: Fusion technology facilitated precise anatomical localization of {sup 18}F-FDOPA activity. In group I, all 21 cases showed pathology-confirmed tumor. Of these, {sup 18}F-FDOPA scans were positive in 9/10 (90%) previously unresected tumors, and 11/11 (100%) of recurrent tumors. Of the 70 patients in group II, concordance between MRI and {sup 18}F-FDOPA was found in 49/54 (90.1%) of patients with sufficient follow-up; in the remaining 16 patients concordance could not be determined due to lack of follow-up. {sup 18}F-FDOPA labeling was comparable in both high- and low-grade gliomas and identified both enhancing and non-enhancing tumor equally well. In some cases, {sup 18}F-FDOPA activity preceded tumor detection on MRI. Conclusion: {sup 18}F-FDOPA PET/MRI fusion provides precise anatomic localization of tracer uptake and labels enhancing and non-enhancing tumor well. In a small minority of cases, {sup 18}F-FDOPA activity may identify tumor not visible on MRI.

  4. Evaluation of kinetic entropy of breast masses initially found on MRI using whole-lesion curve distribution data: Comparison with the standard kinetic analysis

    Shimauchi, Akiko [University of Chicago, Department of Radiology, Chicago, IL (United States); Tohoku University, Department of Diagnostic Radiology, Graduate School of Medicine, Sendai, Miyagi (Japan); Abe, Hiroyuki; Schacht, David V.; Yulei, Jian; Pineda, Federico D.; Jansen, Sanaz A.; Ganesh, Rajiv; Newstead, Gillian M. [University of Chicago, Department of Radiology, Chicago, IL (United States)

    2015-08-15

    To quantify kinetic heterogeneity of breast masses that were initially detected with dynamic contrast-enhanced MRI, using whole-lesion kinetic distribution data obtained from computer-aided evaluation (CAE), and to compare that with standard kinetic curve analysis. Clinical MR images from 2006 to 2011 with breast masses initially detected with MRI were evaluated with CAE. The relative frequencies of six kinetic patterns (medium-persistent, medium-plateau, medium-washout, rapid-persistent, rapid-plateau, rapid-washout) within the entire lesion were used to calculate kinetic entropy (KE), a quantitative measure of enhancement pattern heterogeneity. Initial uptake (IU) and signal enhancement ratio (SER) were obtained from the most-suspicious kinetic curve. Mann-Whitney U test and ROC analysis were conducted for differentiation of malignant and benign masses. Forty benign and 37 malignant masses comprised the case set. IU and SER were not significantly different between malignant and benign masses, whereas KE was significantly greater for malignant than benign masses (p = 0.748, p = 0.083, and p < 0.0001, respectively). Areas under ROC curve for IU, SER, and KE were 0.479, 0.615, and 0.662, respectively. Quantification of kinetic heterogeneity of whole-lesion time-curve data with KE has the potential to improve differentiation of malignant from benign breast masses on breast MRI. (orig.)

  5. MRI-guided breast biopsy at 3T using a dedicated large core biopsy set: Feasibility and initial results

    Meeuwis, Carla, E-mail: cmeeuwis@alysis.nl [Department of Radiology, Radboud University Nijmegen Medical Centre, Geert Grooteplein-Zuid 10, 6525GA Nijmegen (Netherlands); Department of Radiology, Rijnstate Hospital, Alysis Zorggroep, Wagnerlaan 55, 6815 AD Arnhem (Netherlands); Mann, Ritse M., E-mail: r.mann@rad.umcn.nl [Department of Radiology, Radboud University Nijmegen Medical Centre, Geert Grooteplein-Zuid 10, 6525GA Nijmegen (Netherlands); Mus, Roel D.M., E-mail: r.mus@rad.umcn.nl [Department of Radiology, Radboud University Nijmegen Medical Centre, Geert Grooteplein-Zuid 10, 6525GA Nijmegen (Netherlands); Winkel, Axel, E-mail: awinkel@invivocorp.de [Interventional Instruments, INVIVO Germany GMBH, Schwerin (Germany); Boetes, Carla, E-mail: c.boetes@mumc.nl [Department of Radiology, Radboud University Nijmegen Medical Centre, Geert Grooteplein-Zuid 10, 6525GA Nijmegen (Netherlands); Department of Radiology, Maastricht University Medical Center (Netherlands); Barentsz, Jelle O., E-mail: j.barentsz@rad.umcn.nl [Department of Radiology, Radboud University Nijmegen Medical Centre, Geert Grooteplein-Zuid 10, 6525GA Nijmegen (Netherlands); Veltman, Jeroen, E-mail: veltman@rad.umcn.nl [Department of Radiology, Radboud University Nijmegen Medical Centre, Geert Grooteplein-Zuid 10, 6525GA Nijmegen (Netherlands)

    2011-08-15

    Objective: The increasing importance of breast MRI in the diagnostic processes concerning breast cancer yield often lesions that are visible on MRI only. To assess the nature of these lesions, pathologic analysis is necessary. Therefore, MR-guided biopsy should be available. Breast MRI at 3T has shown advantage over 1.5T. Unfortunately, current equipment for MR-guided biopsy is better suited for intervention at 1.5T due to the danger of heating titanium co-axial sleeves and large susceptibility artifacts. We evaluated a dedicated 3T breast biopsy set that uses plastic coaxial needles to overcome these problems. Materials and methods: We performed MRI-guided breast biopsy in 23 women with 24 MRI-only visible breast lesions at 3T. Biopsy procedures were performed with plastic coaxial needles in a closed bore 3T clinical MR system on a dedicated phased array breast coil with a commercially available add-on stereotactic biopsy device. Results: Width of the needle artifact was 2 mm in all 24 cases. Biopsy procedure was completed between 35 and 67 min. The procedure was judged moderately easy in 12 and normal in 10 cases. One procedure was judged difficult and there was one technical failure. Conclusion: MRI-guided breast biopsy at 3T is a fast and accurate procedure. The plastic coaxial needles reduce the susceptibility artifact largely and do not increase the difficulty of the procedure. The diagnostic yield is at least equal to the diagnostic yield of the same procedure at 1.5T. Therefore, this technique can be safely used for lesions only visible at 3T MRI.

  6. Simultaneous measurement of kidney function by dynamic contrast enhanced MRI and FITC-sinistrin clearance in rats at 3 tesla: initial results.

    Frank G Zöllner

    Full Text Available Glomerular filtration rate (GFR is an essential parameter of kidney function which can be measured by dynamic contrast enhanced magnetic resonance imaging (MRI-GFR and transcutaneous approaches based on fluorescent tracer molecules (optical-GFR. In an initial study comparing both techniques in separate measurements on the same animal, the correlation of the obtained GFR was poor. The goal of this study was to investigate if a simultaneous measurement was feasible and if thereby, the discrepancies in MRI-GFR and optical-GFR could be reduced. For the experiments healthy and unilateral nephrectomised (UNX Sprague Dawley (SD rats were used. The miniaturized fluorescent sensor was fixed on the depilated back of an anesthetized rat. A bolus of 5 mg/100 g b.w. of FITC-sinistrin was intravenously injected. For dynamic contrast enhanced perfusion imaging (DCE-MRI a 3D time-resolved angiography with stochastic trajectories (TWIST sequence was used. By means of a one compartment model the excretion half-life (t1/2 of FITC-sinistrin was calculated and converted into GFR. GFR from DCE-MRI was calculated by fitting pixel-wise a two compartment renal filtration model. Mean cortical GFR and GFR by FITC-sinistrin were compared by Bland-Altman plots and pair-wise t-test. Results show that a simultaneous GFR measurement using both techniques is feasible. Mean optical-GFR was 4.34 ± 2.22 ml/min (healthy SD rats and 2.34 ± 0.90 ml/min (UNX rats whereas MRI-GFR was 2.10 ± 0.64 ml/min (SD rats and 1.17 ± 0.38 ml/min (UNX rats. Differences between healthy and UNX rats were significant (p<0.05 and almost equal percentage difference (46.1% and 44.3% in mean GFR were assessed with both techniques. Overall mean optical-GFR values were approximately twice as high compared to MRI-GFR values. However, compared to a previous study, our results showed a higher agreement. In conclusion, the possibility to use the transcutaneous method in MRI may have a huge impact in

  7. Predicting response before initiation of neoadjuvant chemotherapy in breast cancer using new methods for the analysis of dynamic contrast enhanced MRI (DCE MRI) data

    DeGrandchamp, Joseph B.; Whisenant, Jennifer G.; Arlinghaus, Lori R.; Abramson, V. G.; Yankeelov, Thomas E.; Cárdenas-Rodríguez, Julio

    2016-03-01

    The pharmacokinetic parameters derived from dynamic contrast enhanced (DCE) MRI have shown promise as biomarkers for tumor response to therapy. However, standard methods of analyzing DCE MRI data (Tofts model) require high temporal resolution, high signal-to-noise ratio (SNR), and the Arterial Input Function (AIF). Such models produce reliable biomarkers of response only when a therapy has a large effect on the parameters. We recently reported a method that solves the limitations, the Linear Reference Region Model (LRRM). Similar to other reference region models, the LRRM needs no AIF. Additionally, the LRRM is more accurate and precise than standard methods at low SNR and slow temporal resolution, suggesting LRRM-derived biomarkers could be better predictors. Here, the LRRM, Non-linear Reference Region Model (NRRM), Linear Tofts model (LTM), and Non-linear Tofts Model (NLTM) were used to estimate the RKtrans between muscle and tumor (or the Ktrans for Tofts) and the tumor kep,TOI for 39 breast cancer patients who received neoadjuvant chemotherapy (NAC). These parameters and the receptor statuses of each patient were used to construct cross-validated predictive models to classify patients as complete pathological responders (pCR) or non-complete pathological responders (non-pCR) to NAC. Model performance was evaluated using area under the ROC curve (AUC). The AUC for receptor status alone was 0.62, while the best performance using predictors from the LRRM, NRRM, LTM, and NLTM were AUCs of 0.79, 0.55, 0.60, and 0.59 respectively. This suggests that the LRRM can be used to predict response to NAC in breast cancer.

  8. Performance of gadofosveset-enhanced MRI for staging rectal cancer nodes: can the initial promising results be reproduced?

    Heijnen, Luc A.; Martens, Milou H. [Maastricht University Medical Center, Department of Radiology, P.O. Box 5800, Maastricht (Netherlands); Maastricht University Medical Center, Department of Surgery, Maastricht (Netherlands); GROW School for Oncology and Developmental Biology, Maastricht (Netherlands); Lambregts, Doenja M.J.; Maas, Monique; Bakers, Frans C.H. [Maastricht University Medical Center, Department of Radiology, P.O. Box 5800, Maastricht (Netherlands); Cappendijk, Vincent C. [Jeroen Bosch Ziekenhuis, Department of Radiology, ' s Hertogenbosch (Netherlands); Oliveira, Pedro [Instituto Portugues de Oncologia do Porto Francisco Gentil, Department of Radiology, Porto (Portugal); Lammering, Guido [Maastro Clinic, Radiation Oncology, Maastricht (Netherlands); GROW School for Oncology and Developmental Biology, Maastricht (Netherlands); Riedl, Robert G. [Maastricht University Medical Center, Department of Pathology, Maastricht (Netherlands); Beets, Geerard L. [Maastricht University Medical Center, Department of Surgery, Maastricht (Netherlands); GROW School for Oncology and Developmental Biology, Maastricht (Netherlands); Beets-Tan, Regina G.H. [Maastricht University Medical Center, Department of Radiology, P.O. Box 5800, Maastricht (Netherlands); GROW School for Oncology and Developmental Biology, Maastricht (Netherlands)

    2014-02-15

    A previous study showed promising results for gadofosveset-trisodium as a lymph node magnetic resonance imaging (MRI) contrast agent in rectal cancer. The aim of this study was to prospectively confirm the diagnostic performance of gadofosveset MRI for nodal (re)staging in rectal cancer in a second patient cohort. Seventy-one rectal cancer patients were prospectively included, of whom 13 (group I) underwent a primary staging gadofosveset MRI (1.5-T) followed by surgery (± preoperative 5 x 5 Gy) and 58 (group II) underwent both primary staging and restaging gadofosveset MRI after a long course of chemoradiotherapy followed by surgery. Nodal status was scored as (y)cN0 or (y)cN+ by two independent readers (R1, R2) with different experience levels. Results were correlated with histology on a node-by-node basis. Sensitivity, specificity and area under the receiver operating characteristics curve (AUC) were 94 %, 79 % and 0.89 for the more experienced R1 and 50 %, 83 % and 0.74 for the non-experienced R2. R2's performance improved considerably after a learning curve, to an AUC of 0.83. Misinterpretations mainly occurred in nodes located in the superior mesorectum, nodes located in between vessels and nodes containing micrometastases. This prospective study confirms the good diagnostic performance of gadofosveset MRI for nodal (re)staging in rectal cancer. (orig.)

  9. SU-D-18C-06: Initial Experience with Implementing MRI Safety Guidelines for Patients with Pacemakers - Medical Physicist Perspective

    James, J; Place, V; Panda, A [Mayo Clinic, Scottsdale, AZ (United States); Edmonson, H [Mayo Clinic College of Medicine, Rochester, MN (United States); Felmlee, J [Mayo Clinic, Rochester, MN (United States); Pooley, R [Mayo Clinic, Jacksonville, FL (United States)

    2014-06-01

    Purpose: Several institutions have developed MRI guidelines for patients with MR-unsafe or MR-conditional pacemakers. Here we highlight the role of a medical physicist in implementing these guidelines for non-pacemaker dependent patients. Guidelines: Implementing these guidelines requires involvement from several medical specialties and a strong collaboration with the site MRI supervisor to develop a structured workflow. A medical physicist is required to be present during the scan to supervise the MR scanning and to maintain a safety checklist that ensures: 1) uninterrupted patient communication with the technologist, 2) continuous patient physiologic monitoring (e.g. blood pressure and electrocardiography) by a trained nurse, 3) redundant patient vitals monitoring (e.g. pulse oximetry) due to the possibility of in vivo electrocardiography reading fluctuations during image acquisition. A radiologist is strongly recommended to be available to review the images before patients are discharged from the scanner. Pacemaker MRI should be restricted to 1.5T field strength. The MRI sequences should be optimized by the physicist with regards to: a) SAR: limited to <1.5 W/Kg for MR-unsafe pacemakers in normal operating mode, b) RF exposure time: <30 min, c) Coils: use T/R coils but not restricted to such, d) Artifacts: further optimization of sequences whenever image quality is compromised due to the pacemaker. In particular, cardiac, breast and left-shoulder MRIs are most susceptible to these artifacts. Possible strategies to lower the SAR include: a) BW reduction, 2) echo-train-length reduction, 3) increase TR, 4) decrease number of averages, 5) decrease flip angle, 6) reduce slices and/or a combination of all the options. Conclusion: A medical physicist in collaboration with the MR supervisor plays an important role in the supervision/implementation of safe MR scanning of pacemaker patients. Developing and establishing a workflow has enabled our institution to scan over

  10. Dynamic contrast-enhanced MRI assessment of hyperemic fractional microvascular blood plasma volume in peripheral arterial disease: initial findings.

    Bas Versluis

    Full Text Available OBJECTIVES: The aim of the current study was to describe a method that assesses the hyperemic microvascular blood plasma volume of the calf musculature. The reversibly albumin binding contrast agent gadofosveset was used in dynamic contrast-enhanced magnetic resonance imaging (DCE MRI to assess the microvascular status in patients with peripheral arterial disease (PAD and healthy controls. In addition, the reproducibility of this method in healthy controls was determined. MATERIALS AND METHODS: Ten PAD patients with intermittent claudication and 10 healthy control subjects were included. Patients underwent contrast-enhanced MR angiography of the peripheral arteries, followed by one DCE MRI examination of the musculature of the calf. Healthy control subjects were examined twice on different days to determine normative values and the interreader and interscan reproducibility of the technique. The MRI protocol comprised dynamic imaging of contrast agent wash-in under reactive hyperemia conditions of the calf musculature. Using pharmacokinetic modeling the hyperemic fractional microvascular blood plasma volume (V(p, unit: % of the anterior tibial, gastrocnemius and soleus muscles was calculated. RESULTS: V(p was significantly lower for all muscle groups in PAD patients (4.3±1.6%, 5.0±3.3% and 6.1±3.6% for anterior tibial, gastrocnemius and soleus muscles, respectively compared to healthy control subjects (9.1±2.0%, 8.9±1.9% and 9.3±2.1%. Differences in V(p between muscle groups were not significant. The coefficient of variation of V(p varied from 10-14% and 11-16% at interscan and interreader level, respectively. CONCLUSIONS: Using DCE MRI after contrast-enhanced MR angiography with gadofosveset enables reproducible assessment of hyperemic fractional microvascular blood plasma volume of the calf musculature. V(p was lower in PAD patients than in healthy controls, which reflects a promising functional (hemodynamic biomarker for the

  11. Tumor perfusion assessed by dynamic contrast-enhanced MRI correlates to the grading of renal cell carcinoma: Initial results

    Palmowski, Moritz, E-mail: mpalmowski@ukaachen.d [Department of Experimental Molecular Imaging, Medical Faculty, RWTH Aachen University, Aachen (Germany); Department of Diagnostic Radiology, Medical Faculty, RWTH Aachen University, Aachen (Germany); Schifferdecker, Isabel [Department of Diagnostic and Interventional Radiology, Heidelberg University, Heidelberg (Germany); Division of Medical Physics in Radiology, German Cancer Research Center, Heidelberg (Germany); Zwick, Stefan [Division of Medical Physics in Radiology, German Cancer Research Center, Heidelberg (Germany); Macher-Goeppinger, Stephan [Institute of Pathology, Heidelberg University, Heidelberg (Germany); Laue, Hendrik [MeVis Research, Center for Medical Image Computing, Bremen (Germany); Haferkamp, Axel [Department of Urology, Heidelberg University (Germany); Kauczor, Hans-Ulrich [Department of Diagnostic and Interventional Radiology, Heidelberg University, Heidelberg (Germany); Kiessling, Fabian [Department of Experimental Molecular Imaging, Medical Faculty, RWTH Aachen University, Aachen (Germany); Hallscheidt, Peter [Department of Diagnostic and Interventional Radiology, Heidelberg University, Heidelberg (Germany)

    2010-06-15

    In this study, we investigated whether assessment of the tumor perfusion by dynamic contrast-enhanced magnetic resonance imaging (DCE MRI) enables to estimate the morphologic grading of renal cell carcinomas. A total of 21 patients with suspected renal cell cancer were examined using a Gadobutrol-enhanced, dynamic saturation-recovery, turbo-fast, low-angle shot sequence. Tumor perfusion and the tissue-blood ratio within the entire tumor and the most highly vascularized part of the tumor were calculated according to the model of Miles. Immediately after examination, patients underwent surgery, and the results from imaging were compared with the morphological analysis of the histologic grading. Fourteen patients had G2 tumors, and seven patients had G3 tumors. Significantly higher perfusion values (p < 0.05) were obtained in G3 tumors than in G2 tumors when the entire tumor area was considered (1.59 {+-} 0.44 (ml/g/min) vs. 1.08 {+-} 0.38 (ml/g/min)) or its most highly vascularized part (2.14 {+-} 0.89 (ml/g/min) vs. 1.40 {+-} 0.49 (ml/g/min)). By contrast, the tissue-blood ratios did not differ significantly between the two groups. In conclusion, unlike tissue-blood ratio, surrogate parameters of the tumor perfusion determined by DCE MRI seem to allow an estimation of the grading of renal cell carcinoma. However, further studies with high case numbers and including patients with G1 tumors are required to evaluate the full potential and clinical impact.

  12. Semi-automatic lung segmentation of DCE-MRI data sets of 2-year old children after congenital diaphragmatic hernia repair: Initial results.

    Zöllner, Frank G; Daab, Markus; Weidner, Meike; Sommer, Verena; Zahn, Katrin; Schaible, Thomas; Weisser, Gerald; Schoenberg, Stefan O; Neff, K Wolfgang; Schad, Lothar R

    2015-12-01

    In congenital diaphragmatic hernia (CDH), lung hypoplasia and secondary pulmonary hypertension are the major causes of death and severe disability. Based on new therapeutic strategies survival rates could be improved to up to 80%. However, after surgical repair of CDH, long-term follow-up of these pediatric patients is necessary. In this, dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) provides insights into the pulmonary microcirculation and might become a tool within the routine follow-up program of CDH patients. However, whole lung segmentation from DCE-MRI scans is tedious and automated procedures are warranted. Therefore, in this study, an approach to semi-automated lung segmentation is presented. Segmentation of the lung is obtained by calculating the cross correlation and the area under curve between all voxels in the data set and a reference region-of-interest (ROI), here the arterial input function (AIF). By applying an upper and lower threshold to the obtained maps and intersecting these, a final segmentation is reached. This approach was tested on twelve DCE-MRI data sets of 2-year old children after CDH repair. Segmentation accuracy was evaluated by comparing obtained automatic segmentations to manual delineations using the Dice overlap measure. Optimal thresholds for the cross correlation were 0.5/0.95 and 0.1/0.5 for the area under curve, respectively. The ipsilateral (left) lung showed reduced segmentation accuracy compared to the contralateral (right) lung. Average processing time was about 1.4s per data set. Average Dice score was 0.7±0.1 for the whole lung. In conclusion, initial results are promising. By our approach, whole lung segmentation is possible and a rapid evaluation of whole lung perfusion becomes possible. This might allow for a more detailed analysis of lung hypoplasia of children after CDH.

  13. Altered baseline brain activity with 72 h of simulated microgravity--initial evidence from resting-state fMRI.

    Yang Liao

    Full Text Available To provide the basis and reference to further insights into the neural activity of the human brain in a microgravity environment, we discuss the amplitude changes of low-frequency brain activity fluctuations using a simulated microgravity model. Twelve male participants between 24 and 31 years old received resting-state fMRI scans in both a normal condition and after 72 hours in a -6° head down tilt (HDT. A paired sample t-test was used to test the amplitude differences of low-frequency brain activity fluctuations between these two conditions. With 72 hours in a -6° HDT, the participants showed a decreased amplitude of low-frequency fluctuations in the left thalamus compared with the normal condition (a combined threshold of P<0.005 and a minimum cluster size of 351 mm(3 (13 voxels, which corresponded with the corrected threshold of P<0.05 determined by AlphaSim. Our findings indicate that a gravity change-induced redistribution of body fluid may disrupt the function of the left thalamus in the resting state, which may contribute to reduced motor control abilities and multiple executive functions in astronauts in a microgravity environment.

  14. Initial PET Performance Evaluation of a Preclinical Insert for PET/MRI with Digital SiPM Technology

    Schug, David; Weissler, Bjoern; Gebhardt, Pierre; Goldschmidt, Benjamin; Wehner, Jakob; Dueppenbecker, Peter Michael; Salomon, Andre; Hallen, Patrick; Kiessling, Fabian; Schulz, Volkmar

    2015-01-01

    Hyperion-IID is a positron emission tomography (PET) insert which allows simultaneous operation in a clinical magnetic resonance imaging (MRI) scanner. To read out the scintillation light of the employed LYSO crystal arrays with a pitch of 1 mm pitch and 12 mm in height, digital silicon photomultipliers (DPC 3200-22, Philips Digital Photon Counting) (DPC) are used. The basic PET performance in terms of energy resolution, coincidence resolution time (CRT) and sensitivity as a function of operating parameters, such as the operating temperature, the applied overvoltage, activity and configuration parameters of the DPCs, were evaluated on system level. The measured energy resolution did not show a large dependency on the selected parameters and is in the range of 12.4-12.9% for low activities and degrades to ~13.6% at activities of ~100 MBq. The CRT strongly depends on the selected trigger scheme (trig) of the DPCs. We measured approximately 260 ps, 440 ps, 540 ps and 1300 ps for trig 1-4, respectively. The trues...

  15. Chest MRI

    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 ...

  16. Rendering of 3D Dynamic Virtual Environments

    Catanese, Salvatore; Fiumara, Giacomo; Pagano, Francesco

    2011-01-01

    In this paper we present a framework for the rendering of dynamic 3D virtual environments which can be integrated in the development of videogames. It includes methods to manage sounds and particle effects, paged static geometries, the support of a physics engine and various input systems. It has been designed with a modular structure to allow future expansions. We exploited some open-source state-of-the-art components such as OGRE, PhysX, ParticleUniverse, etc.; all of them have been properly integrated to obtain peculiar physical and environmental effects. The stand-alone version of the application is fully compatible with Direct3D and OpenGL APIs and adopts OpenAL APIs to manage audio cards. Concluding, we devised a showcase demo which reproduces a dynamic 3D environment, including some particular effects: the alternation of day and night infuencing the lighting of the scene, the rendering of terrain, water and vegetation, the reproduction of sounds and atmospheric agents.

  17. Obesity increases the prevalence and severity of focal knee abnormalities diagnosed using 3T MRI in middle-aged subjects - data from the osteoarthritis initiative

    Laberge, Marc A.; Baum, Thomas; Virayavanich, Warapat; Nardo, Lorenzo; Link, Thomas M. [University of California San Francisco, Musculoskeletal and Quantitative Imaging Research, Department of Radiology and Biomedical Imaging, San Francisco, CA (United States); Nevitt, M.C.; Lynch, J.; McCulloch, C.E. [University of California San Francisco, Department of Epidemiology and Biostatistics, San Francisco, CA (United States)

    2012-06-15

    To study the effect of BMI on the prevalence, severity, and 36-month progression of early degenerative changes in the knee by using 3T MRI in middle-aged subjects without radiographic osteoarthritis (OA). We examined baseline and 36-month follow-up MR studies from 137 middle-aged individuals (45-55 years old) with risk factors for knee OA but no radiographic OA from the Osteoarthritis Initiative. Subjects were grouped into three categories: normal BMI (BMI < 25 kg/m{sup 2}, n = 38), overweight (BMI 25-29.9 kg/m{sup 2}, n = 37), and obese (BMI {>=} 30 kg/m{sup 2}, n = 62). Using 3T MRI, cartilage, meniscus, and bone marrow abnormalities were graded using the OA Whole-organ MR Imaging Score (WORMS). The statistical analysis was corrected as necessary for differences in age, sex, and OA risk factors other than BMI. The overall prevalence of lesions was 64% for meniscus and 79% for cartilage (including low grade lesions). At baseline, the prevalence and severity of knee lesions was positively associated with BMI, with a nearly fourfold increase in meniscal tears and more than twofold increase in high-grade cartilage defects in obese individuals relative to normal-weight subjects. Over the 36-month follow-up period, the number of new or worsening cartilage lesions of any grade was significantly higher in obese subjects (p = 0.039), while there was no significant difference in meniscal lesion progression. Obesity was associated with both higher prevalence and severity of early degenerative changes in the knee in middle-aged individuals without radiographic OA and with significantly increased cartilage lesion progression (of any grade) over 36 months. (orig.)

  18. MRI and low back pain

    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 ...

  19. 电力计量检定数字化车间3D动态感知监控技术研究%3D dynamic perception monitoring technologies of the digital workshop for electric power measurement calibration

    蔡奇新; 邵雪松; 刘建; 王忠东; 黄奇峰

    2015-01-01

    For the operation stability requirement of the electric power measurement calibration digital workshop, this submission designs and builds 3D dynamic perception monitoring system. The monitoring technical architecture is based on the data layer, the communication layer, the service layer, and the exhibition layer. In order to reduce the com-putation complexity, the simulation monitoring system emploies the step by step hierarchical modeling method, which contains the appearance design, the behavior modeling, the simulation program design, and the simulation scene con-struction. Also, the 3D scene optimization strategy includes the model optimization, the program optimization and the composite optimization. The technology of the second level data synchronization and stream processing is proposed to distribute data processing pressure. The process smoothing and data fault tolerance mechanism are adopted to ensure the consistency of the 3D monitoring scene and the actual production. The 3D dynamic perception monitoring system of the electric power measurement calibration digital workshop has been applied in 26 companies of state grid. It has been real-ized virtual patrol and examination, and cooperative fault processing. The 3D dynamic perception monitoring system has improved the operation efficiency of calibration digital workshops significantly.%针对电力计量检定数字化车间稳定性运行要求,本文设计并建立一种数字化车间3D动态感知监控系统。设计基于数据层、传输层、服务层、展示层的监控系统技术架构。为降低仿真监控系统计算复杂度,采用外观建模、行为建模、仿真程序设计、仿真场景搭建的逐级分层建模方法,并对3D场景进行模型优化、程序优化、综合优化。提出秒级生产数据同步与流式处理技术,分散数据处理压力,采用过程平滑处理与数据容错机制,确保3D监控系统与实际生产过程同步。本文设计的

  20. Whole-body MRI for initial staging of paediatric lymphoma: prospective comparison to an FDG-PET/CT-based reference standard

    Littooij, Annemieke S. [University Medical Centre Utrecht/Wilhelmina Children' s Hospital, Department of Radiology and Nuclear Medicine, Utrecht (Netherlands); KK Women' s and Children' s Hospital, Department of Diagnostic and Interventional Imaging, Singapore (Singapore); Kwee, Thomas C.; Vermoolen, Malou A.; Keizer, Bart de; Beek, Frederik J.A.; Hobbelink, Monique G.; Nievelstein, Rutger A.J. [University Medical Centre Utrecht/Wilhelmina Children' s Hospital, Department of Radiology and Nuclear Medicine, Utrecht (Netherlands); Barber, Ignasi; Enriquez, Goya [Hospital Materno-Infantil Vall d' Hebron, Department of Paediatric Radiology, Barcelona (Spain); Granata, Claudio [IRCCS Giannina Gaslini Hospital, Department of Radiology, Genoa (Italy); Zsiros, Jozsef [University of Amsterdam, Department of Paediatric Oncology, Emma Children' s Hospital, Academic Medical Centre, Amsterdam (Netherlands); Soh, Shui Yen [KK Women' s and Children' s Hospital, Haematology and Oncology service, Department of Paediatric Subspecialities, Singapore (Singapore); Bierings, Marc B. [University Medical Centre Utrecht/Wilhelmina Children' s Hospital, Department of Paediatric Haematology-Oncology, Utrecht (Netherlands); Stoker, Jaap [University of Amsterdam, Department of Radiology, Academic Medical Centre, Amsterdam (Netherlands)

    2014-05-15

    To compare whole-body MRI, including diffusion-weighted imaging (whole-body MRI-DWI), with FDG-PET/CT for staging newly diagnosed paediatric lymphoma. A total of 36 children with newly diagnosed lymphoma prospectively underwent both whole-body MRI-DWI and FDG-PET/CT. Whole-body MRI-DWI was successfully performed in 33 patients (mean age 13.9 years). Whole-body MRI-DWI was independently evaluated by two blinded observers. After consensus reading, an unblinded expert panel evaluated the discrepant findings between whole-body MRI-DWI and FDG-PET/CT and used bone marrow biopsy, other imaging data and clinical information to derive an FDG-PET/CT-based reference standard. Interobserver agreement of whole-body MRI-DWI was good [all nodal sites together (κ = 0.79); all extranodal sites together (κ = 0.69)]. There was very good agreement between the consensus whole-body MRI-DWI- and FDG-PET/CT-based reference standard for nodal (κ = 0.91) and extranodal (κ = 0.94) staging. The sensitivity and specificity of consensus whole-body MRI-DWI were 93 % and 98 % for nodal staging and 89 % and 100 % for extranodal staging, respectively. Following removal of MRI reader errors, the disease stage according to whole-body MRI-DWI agreed with the reference standard in 28 of 33 patients. Our results indicate that whole-body MRI-DWI is feasible for staging paediatric lymphoma and could potentially serve as a good radiation-free alternative to FDG-PET/CT. (orig.)

  1. Educational attainment, MRI changes, and cognitive function in older postmenopausal women from the Women's Health Initiative Memory Study.

    Rapp, Stephen R; Espeland, Mark A; Manson, Joann E; Resnick, Susan M; Bryan, Nick R; Smoller, Sylvia; Coker, Laura H; Phillips, Lawrence S; Stefanick, Marcia L; Sarto, Gloria E

    2013-01-01

    The relationship between neuropathology and clinically manifested functional and cognitive deficits is complex. Clinical observations of individuals with greater neuropathology who function better than some individuals with less neuropathology are common and puzzling. Educational attainment, a proxy for "cognitive reserve," may help to explain this apparent contradiction. The objective of this study is to determine if educational attainment is correlated with cognitive decline, brain lesion volume, and total brain atrophy. One thousand three hundred ninety of the 7,479 community-dwelling women 65 years of age and older enrolled in the Women's Health Initiative Memory Study, two parallel randomized, placebo-controlled clinical trials comparing unopposed and opposed postmenopausal hormone therapy with placebo, were studied. Study participants received annual assessments of global cognitive function with the Modified Mini Mental State exam. One thousand sixty-three participants also received supplemental neurocognitive battery and neuroimaging studies. Magnetic resonance imaging was used to calculate total ischemic lesion and brain volumes. Incident cases of probable dementia and mild cognitive impairment were centrally adjudicated. After adjustment for total lesion and total brain volumes (atrophy), higher educational attainment predicted better cognitive performance (p cognitive function (p < 0.001). Thus, higher educational attainment was associated with a delay in diagnosis of dementia/MCI in the face of a growing neuropathological load.

  2. Longitudinal analysis of MRI T(2) knee cartilage laminar organization in a subset of patients from the osteoarthritis initiative.

    Carballido-Gamio, Julio; Blumenkrantz, Gabrielle; Lynch, John A; Link, Thomas M; Majumdar, Sharmila

    2010-02-01

    The purpose of this pilot study was to longitudinally quantify the T(2) laminar integrity of knee cartilage in a subset of subjects with osteoarthritis from the Osteoarthritis Initiative at baseline, 1-year follow-up, and 2-year follow-up. Cartilage from 13 subjects was divided into six compartments and subdivided into deep and superficial layers. At each time point, mean T(2) values in superficial and deep layers were compared. Longitudinal analysis included full-thickness mean T(2), mean deep T(2), mean superficial T(2), mean T(2) laminar difference, mean percentage T(2) laminar difference, and two-dimensional measures of cartilage thickness. More compartments showed significantly higher superficial T(2) than deep T(2) values at baseline and 1-year follow-up compared to 2-year follow-up. No significant longitudinal changes of full-thickness mean T(2) and superficial T(2) values were observed. Significant longitudinal changes were observed in the deep T(2) values, T(2) laminar difference, and percentage T(2) laminar difference. Cartilage thickness had no influence on T(2) analysis. Results of this study suggest that laminar analysis may improve the sensitivity to detect longitudinal T(2) changes and that disruption of the T(2) laminar organization of knee cartilage may be present in knee osteoarthritis progressors. Further investigation is warranted to evaluate the potential of the presented methodology to better characterize evolution and pathophysiology of osteoarthritis.

  3. Simultaneous evaluation of brain tumour metabolism, structure and blood volume using [{sup 18}F]-fluoroethyltyrosine (FET) PET/MRI: feasibility, agreement and initial experience

    Henriksen, Otto M.; Hansen, Adam E.; Law, Ian [Copenhagen University Hospital Rigshospitalet Blegdamsvej, Department of Clinical Physiology Nuclear Medicine and PET, Copenhagen (Denmark); Larsen, Vibeke A. [Copenhagen University Hospital Rigshospitalet Blegdamsvej, Department of Radiology, Copenhagen (Denmark); Muhic, Aida; Poulsen, Hans S. [Copenhagen University Hospital Rigshospitalet Blegdamsvej, Department of Oncology, Copenhagen (Denmark); Larsson, Henrik B.W. [Copenhagen University Hospital Rigshospitalet Glostrup, Functional Imaging Unit, Department of Clinical Physiology Nuclear Medicine and PET, Glostrup (Denmark)

    2016-01-15

    Both [{sup 18}F]-fluoroethyltyrosine (FET) PET and blood volume (BV) MRI supplement routine T1-weighted contrast-enhanced MRI in gliomas, but whether the two modalities provide identical or complementary information is unresolved. The aims of the study were to investigate the feasibility of simultaneous structural MRI, BV MRI and FET PET of gliomas using an integrated PET/MRI scanner and to assess the spatial and quantitative agreement in tumour imaging between BV MRI and FET PET. A total of 32 glioma patients underwent a 20-min static simultaneous PET/MRI acquisition on a Siemens mMR system 20 min after injection of 200 MBq FET. The MRI protocol included standard structural MRI and dynamic susceptibility contrast (DSC) imaging for BV measurements. Maximal relative tumour FET uptake (TBR{sub max}) and BV (rBV{sub max}), and Dice coefficients were calculated to assess the quantitative and spatial congruence in the tumour volumes determined by FET PET, BV MRI and contrast-enhanced MRI. FET volume and TBR{sub max} were higher in BV-positive than in BV-negative scans, and both VOL{sub BV} and rBV{sub max} were higher in FET-positive than in FET-negative scans. TBR{sub max} and rBV{sub max} were positively correlated (R{sup 2} = 0.59, p < 0.001). FET and BV positivity were in agreement in only 26 of the 32 patients and in 42 of 63 lesions, and spatial congruence in the tumour volumes as assessed by the Dice coefficients was generally poor with median Dice coefficients exceeding 0.1 in less than half the patients positive on at least one modality for any pair of modalities. In 56 % of the patients susceptibility artefacts in DSC BV maps overlapped the tumour on MRI. The study demonstrated that although tumour volumes determined by BV MRI and FET PET were quantitatively correlated, their spatial congruence in a mixed population of treated glioma patients was generally poor, and the modalities did not provide the same information in this population of patients. Combined

  4. A 3D dynamic teaching system of data structure based on virtual reality%基于虚拟现实的数据结构三维动态教学系统

    杨程; 刘涛; 范勇; 陈念年

    2012-01-01

    Focusing on shortcomings of traditional writing on the blackboard teaching and configuration of educational software in intuitiveness and interesting, a 3D dynamic teaching system of data structure was designed and then realized based on virtual reality technology. By using a hybrid software development method based on VC/MFC and OpenGL, practical teaching software which is simple to use and more intuitiveness was developed. Also, multi-thread technology was used to synchronize the current line of code and the steps of the algorithm. After applying the virtual reality technology to the teaching process, the purpose of improving the teaching of data structure and arising students' inspiration of this primary course was achieved.%针对传统板书式教学和组态式教学软件在直观性和趣味性方面的不足,设计并实现了一种基于虚拟现实技术的数据结构三维动态教学系统.系统以VC/MFC+ OpenGL的混合软件开发方式实现,具备简单、直观、易用并且交互性良好的特点,还利用Windows多线程技术实现了算法演示步骤与代码当前执行行的同步关联运行.课堂教学应用表明,达到了改进数据结构课程教学、提高学生学习该课程积极性的目的.

  5. MRI Scans

    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 ...

  6. Shoulder MRI

    ... 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 ...

  7. 3 Tesla proton MRI for the diagnosis of pneumonia/lung infiltrates in neutropenic patients with acute myeloid leukemia: Initial results in comparison to HRCT

    Attenberger, U.I., E-mail: ulrike.attenberger@umm.de [Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim (Germany); Morelli, J.N. [Scott and White Hospital, Texas A and M Health Sciences Center, Temple (United States); Henzler, T. [Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim (Germany); Buchheidt, D. [Department of Hematology and Oncology, University Medical Center Mannheim (Germany); Fink, C. [Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim (Germany); Department of Radiology, AKH Celle, Celle (Germany); Schoenberg, S.O.; Reichert, M. [Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim (Germany)

    2014-01-15

    Purpose: To evaluate the diagnostic accuracy of 3 Tesla proton MRI for the assessment of pneumonia/lung infiltrates in neutropenic patients with acute myeloid leukemia. Material and methods: In a prospective study, 3 Tesla MRI was performed in 19 febrile neutropenic patients (5 women, 14 men; mean age 61 years ± 14.2; range 23–77 years). All patients underwent high-resolution CT less than 24 h prior to MRI. The MRI protocol (Magnetom Tim Trio, Siemens) included a T2-weighted HASTE sequence (TE/TR: 49 ms/∞, slice thickness 6 mm) and a high-resolution 3D VIBE sequence with an ultra-short TE < 1 ms (TE/TR 0.8/2.9 ms, slice thickness 2 mm). The VIBE sequence was examined before and after intravenous injection of 0.1 mmol/kg gadoterate meglumine (Dotarem, Guerbet). The presence of pulmonary abnormalities, their location within the lung, and lesion type (nodules, consolidations, glass opacity areas) were analyzed by one reader and compared to the findings of HRCT, which was evaluated by a second independent radiologist who served as the reference standard. The findings were compared per lobe in each patient and rated as true positive (TP) findings if all three characteristics (presence, location, and lesion type) listed above were concordant to HRCT. Results: Pulmonary abnormalities were characterized by 3 Tesla MRI with a sensitivity of 82.3% and a specificity of 78.6%, resulting in an overall accuracy of 88% (NPV/PPV 66.7%/89.5%). In 51 lobes (19 of 19 patients), pulmonary abnormalities visualized by MR were judged to be concordant in their location and in the lesion type identified by both readers. In 22 lobes (11 of 19 patients), no abnormalities were present on either MR or HRCT (true negative). In 6 lobes (5 of 19 patients), ground glass opacity areas were detected on MRI but were not visible on HRCT (false positives). In 11 lobes (7 of 19 patients), MRI failed to detect ground glass opacity areas identified by HRCT. However, since the abnormalities were

  8. Spiral Perfusion Imaging With Consecutive Echoes (SPICE™) for the Simultaneous Mapping of DSC- and DCE-MRI Parameters in Brain Tumor Patients: Theory and Initial Feasibility

    Paulson, Eric S.; Prah, Douglas E.; Schmainda, Kathleen M.

    2017-01-01

    Dynamic contrast-enhanced (DCE) and dynamic susceptibility contrast (DSC) magnetic resonance imaging (MRI) are the perfusion imaging techniques most frequently used to probe the angiogenic character of brain neoplasms. With these methods, T1- and T2/T2*-weighted imaging sequences are used to image the distribution of gadolinium (Gd)-based contrast agents. However, it is well known that Gd exhibits combined T1, T2, and T2* shortening effects in tissue, and therefore, the results of both DCE- and DSC-MRI can be confounded by these opposing effects. In particular, residual susceptibility effects compete with T1 shortening, which can confound DCE-MRI parameters, whereas dipolar T1 and T2 leakage and residual susceptibility effects can confound DSC-MRI parameters. We introduce here a novel perfusion imaging acquisition and postprocessing method termed Spiral Perfusion Imaging with Consecutive Echoes (SPICE) that can be used to simultaneously acquire DCE- and DSC-MRI data, which requires only a single dose of the Gd contrast agent, does not require the collection of a precontrast T1 map for DCE-MRI processing, and eliminates the confounding contrast agent effects due to contrast extravasation. A detailed mathematical description of SPICE is provided here along with a demonstration of its utility in patients with high-grade glioma. PMID:28090589

  9. [{sup 18}F]FDG PET/MRI vs. PET/CT for whole-body staging in patients with recurrent malignancies of the female pelvis: initial results

    Beiderwellen, Karsten; Grueneisen, Johannes; Forsting, Michael; Lauenstein, Thomas C.; Umutlu, Lale [University Hospital Essen, University of Duisburg-Essen, Department of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany); Ruhlmann, Verena [University Hospital Essen, University of Duisburg-Essen, Clinic for Nuclear Medicine, Essen (Germany); Buderath, Paul; Aktas, Bahriye [University Hospital Essen, University of Duisburg-Essen, Clinic for Obstetrics and Gynecology, Essen (Germany); Heusch, Philipp [University of Dusseldorf, Department of Diagnostic and Interventional Radiology, Dusseldorf (Germany); Kraff, Oliver [University of Duisburg-Essen, Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen (Germany)

    2015-01-15

    To evaluate the diagnostic potential of PET/MRI with [{sup 18}F]FDG in recurrent ovarian and cervical cancer in comparison to PET/CT. A group of 19 patients with suspected recurrence of pelvic malignancies (ovarian cancer, 11 patients; cervical cancer, 8 patients) scheduled for an [{sup 18}F]FDG PET/CT were subsequently enrolled for a PET/MRI. The scan protocol comprised: (1) a T1-W axial VIBE after contrast agent adminstration, (2) an axial T2-W HASTE, (3) a coronal TIRM, (4) an axial DWI, and dedicated MR sequences of the female pelvis including (5) a T1-W VIBE before contrast agent adminstration, (6) a sagittal T2-W TSE, and (7) a sagittal T1-W dynamic VIBE. The datasets (PET/CT, PET/MRI) were rated separately by two readers regarding lesion count, lesion localization, lesion conspicuity (four-point scale), lesion characterization (benign/malignant/indeterminate) and diagnostic confidence (three-point scale). All available data (histology, prior examinations, PET/CT, PET/MRI, follow-up examinations) served as standard of reference. Median values were compared using the Wilcoxon rank sum test. Metastatic lesions were present in 16 of the 19 patients. A total of 78 lesions (malignant, 58; benign, 20) were described. Both PET/CT and PET/MRI allowed correct identification of all malignant lesions and provided equivalent conspicuity (3.86 ± 0.35 for PET/CT, 3.91 ± 0.28 for PET/MRI; p > 0.05). Diagnostic confidence was significantly higher for PET/MRI in malignant (p < 0.01) and benign lesions (p < 0.05). Both PET/CT and PET/MRI offer an equivalently high diagnostic value for recurrent pelvic malignancies. PET/MRI offers higher diagnostic confidence in the discrimination of benign and malignant lesions. Considering the reduced radiation dose and superior lesion discrimination, PET/MRI may serve as a powerful alternative to PET/CT in the future. (orig.)

  10. Initial experience with lung-MRI at 3.0 T: Comparison with CT and clinical data in the evaluation of interstitial lung disease activity

    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

  11. Utility of Postmortem Autopsy via Whole-Body Imaging: Initial Observations Comparing MDCT and 3.0T MRI Findings with Autopsy Findings

    Cha, Jang Gyu; Kim, Dong Hun; Paik, Sang Hyun [National Institute of Scientific Investigation, Seoul (Korea, Republic of)

    2010-08-15

    We prospectively compared whole-body multidetector computed tomography (MDCT) and 3.0T magnetic resonance (MR) images with autopsy findings. Five cadavers were subjected to whole-body, 16- channel MDCT and 3.0T MR imaging within two hours before an autopsy. A radiologist classified the MDCT and 3.0T MRI findings into major and minor findings, which were compared with autopsy findings. Most of the imaging findings, pertaining to head and neck, heart and vascular, chest, abdomen, spine, and musculoskeletal lesions, corresponded to autopsy findings. The causes of death that were determined on the bases of MDCT and 3.0T MRI findings were consistent with the autopsy findings in four of five cases. CT was useful in diagnosing fatal hemorrhage and pneumothorax, as well as determining the shapes and characteristics of the fractures and the direction of external force. MRI was effective in evaluating and tracing the route of a metallic object, soft tissue lesions, chronicity of hemorrhage, and bone bruises. A postmortem MDCT combined with MRI is a potentially powerful tool, providing noninvasive and objective measurements for forensic investigations

  12. Influence of heavy truck dynamic parameters on ride comfort using 3D dynamic model%基于三维动力学模型的重型卡车动态参数对平顺性的影响

    Le Van Quynh; 张建润; 王园; 孙小娟; Nguyen Van Liem

    2013-01-01

    In order to study the influence of heavy vehicle dynamic parameters on ride comfort with random road excitation,a 3D dynamic model with 13-DOF(degree of freedom) is established for simulation,and the weighted r.m.s acceleration responses of the vertical driver's seat,pitch and roll angle of the cab are chosen as objective functions which uses Matlab/Simulink software to simulate and calculate the objective functions.The influence of the different vehicle dynamics system parameters on the vertical vibration of driver's seat,pitch and roll of the cab which include the stiffness and damping of vehicle suspension,tires,cab suspension and the driver's seat suspension are analyzed in this paper.The results show that the influence of the stiffness and damping parameters in the suspension systems on the vehicle ride comfort is very obvious.The vehicle ride comfort is going to be worse with the increase of the stiffness of the suspension systems and tires.And the vehicle ride comfort is improved with the increase of the damping of the suspension systems.This study can provide a theoretical basis for the suspension system design of heavy trucks.%为了研究重型卡车动态参数对驾驶员舒适性的影响,以路面随机不平度为激扰,以驾驶室座椅垂向、驾驶室的俯仰角和侧倾角的加权加速度均方根值为目标函数,建立了13自由度的三维动力学模型.采用Matlab/Simulink软件对整车模型进行仿真计算,分析了不同系统参数,如悬架、轮胎、驾驶室悬架和驾驶员座椅悬架的参数对驾驶员座椅垂向振动、驾驶室前后和左右晃动的影响.研究结果表明:悬架系统中刚度和阻尼参数的最佳匹配对车辆平顺性的影响非常明显;随着悬架系统和轮胎刚度的增加,车辆平顺性从优向劣转变,而随着悬架系统阻尼的增加,车辆平顺性呈现从劣转优现象.该研究为重型卡车悬架系统设计提供相应的理论依据.

  13. SU-F-303-13: Initial Evaluation of Four Dimensional Diffusion- Weighted MRI (4D-DWI) and Its Effect On Apparent Diffusion Coefficient (ADC) Measurement

    Liu, Y [Duke University Medical Physics Program (United States); Yin, F; Czito, B; Bashir, M; Palta, M; Cai, J [Duke University Medical Center, Durham, NC (United States); Zhong, X; Dale, B [Siemens Healthcare, Durham, NC (United States)

    2015-06-15

    Purpose: Diffusion-weighted imaging(DWI) has been shown to have superior tumor-to-tissue contrast for cancer detection.This study aims at developing and evaluating a four dimensional DWI(4D-DWI) technique using retrospective sorting method for imaging respiratory motion for radiotherapy planning,and evaluate its effect on Apparent Diffusion Coefficient(ADC) measurement. Materials/Methods: Image acquisition was performed by repeatedly imaging a volume of interest using a multi-slice single-shot 2D-DWI sequence in the axial planes and cine MRI(served as reference) using FIESTA sequence.Each 2D-DWI image were acquired in xyz-diffusion-directions with a high b-value(b=500s/mm2).The respiratory motion was simultaneously recorded using bellows.Retrospective sorting was applied in each direction to reconstruct 4D-DWI.The technique was evaluated using a computer simulated 4D-digital human phantom(XCAT),a motion phantom and a healthy volunteer under an IRB-approved study.Motion trajectories of regions-of-interests(ROI) were extracted from 4D-DWI and compared with reference.The mean motion trajectory amplitude differences(D) between the two was calculated.To quantitatively analyze the motion artifacts,XCAT were controlled to simulate regular motion and the motions of 10 liver cancer patients.4D-DWI,free-breathing DWI(FB- DWI) were reconstructed.Tumor volume difference(VD) of each phase of 4D-DWI and FB-DWI from the input static tumor were calculated.Furthermore, ADC was measured for each phase of 4D-DWI and FB-DWI data,and mean tumor ADC values(M-ADC) were calculated.Mean M-ADC over all 4D-DWI phases was compared with M-ADC calculated from FB-DWI. Results: 4D-DWI of XCAT,the motion phantom and the healthy volunteer demonstrated the respiratory motion clearly.ROI D values were 1.9mm,1.7mm and 2.0mm,respectively.For motion artifacts analysis,XCAT 4D-DWI images show much less motion artifacts compare to FB-DWI.Mean VD for 4D-WDI and FB-DWI were 8.5±1.4% and 108±15

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

    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.)

  15. MRI of the Prostate

    ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Prostate Magnetic resonance imaging (MRI) of the prostate ... limitations of MRI of the Prostate? What is MRI of the Prostate? Magnetic resonance imaging (MRI) is ...

  16. MRI assessment program. Consensus statement on clinical efficacy of MRI

    NONE

    1998-05-01

    This consensus statement is largely based on the experience gained at the MRI units at the four hospitals which have operated scanners in the MRI program. It reflects the considered opinion of the radiologists responsible for the MRI services at those hospitals. Account has also been taken of relevant overseas data. This collection of opinion relates particularly to comparison with other imaging modalities. The specific comments will require further consideration as technical developments with MRI become available, additional experience is gained with gadolinium contrast material and additional data are obtained on the influence of MRI on patient management. MRI, at present, is used either to improve diagnostic accuracy when other tests are negative or equivocal, when there is strong clinical suspicion of disease, or to improve surgical or other management planning when the diagnosis known. In some situations (eg syringomyelia, congenital spinal disease, posterior fossa/cerebello-pontine angle tumours) it may entirely replace other tests (eg myelography, air contrast, CT) which are substantially less accurate and/or more invasive. In other situations (eg hemispheric brain tumours, lumbar disc protrusions) when other tests, such as CT, can be as accurate, MRI is not usually or initially indicated because it is currently more expensive and of limited availability. However, balanced against this is the fact that it does not expose the patient to potentially harmful ionising radiation. It is also stressed that MRI images depend on complex, widely variable and, as yet, incompletely understood parameters. There is concern that this may result in false positive diagnoses, especially where MRI is used alone as a screening test, or used as the initial test. For several reasons (availability, cost, medical and diagnostic efficacy), the specific comments on indications for MRI presented are based upon the assumption that MRI is a tertiary and complementary imaging examination

  17. MRI zoo

    Laustsen, Christoffer

    The basic idea was to use MRI to produce a sequence of 3D gray scale image slices of various animals, subsequentlyimaged with a clinical CT system. For this purpose, these animals were used: toad, lungfish, python snake and a horseshoe crab. Each animal was sacrificed according to standard....... MRI was done using a Philips Achieva 1.5 T system and CT was performed using a Siemens Somatom system. Axial and sagittal slices were acquired using standard T1w and T2w MRI sequences, and visualization was made using the Mistar software (Apollo Imaging Technology, Melbourne, Australia). Images were...

  18. Multi-modal MRI analysis with disease-specific spatial filtering: initial testing to predict mild cognitive impairment patients who convert to Alzheimer’s disease

    Kenichi eOishi

    2011-08-01

    Full Text Available Background: Alterations of the gray and white matter have been identified in Alzheimer’s disease (AD by structural MRI and diffusion tensor imaging (DTI. However, whether the combination of these modalities could increase the diagnostic performance is unknown.Methods: Participants included 19 AD patients, 22 amnestic mild cognitive impairment (aMCI patients, and 22 cognitively normal elderly (NC. The aMCI group was further divided into an aMCI-converter group (converted to AD dementia within three years, and an aMCI-stable group who did not convert in this time period. A T1-weighted image, a T2 map, and a DTI of each participant were normalized, and voxel-based comparisons between AD and NC groups were performed. Regions-of-interest, which defined the areas with significant differences between AD and NC, were created for each modality and named disease-specific spatial filters (DSF. Linear discriminant analysis was used to optimize the combination of multiple MRI measurements extracted by DSF to effectively differentiate AD from NC. The resultant DSF and the discriminant function were applied to the aMCI group to investigate the power to differentiate the aMCI-converters from the aMCI-stable patients. Results: The multi-modal approach with AD-specific filters led to a predictive model with an area under the receiver operating characteristic curve (AUC of 0.93, in differentiating aMCI-converters from aMCI-stable patients. This AUC was better than that of a single-contrast-based approach, such as T1-based morphometry or diffusion anisotropy analysis. Conclusion: The multi-modal approach has the potential to increase the value of MRI in predicting conversion from aMCI to AD.

  19. Pediatric MRI

    U.S. Department of Health & Human Services — The NIH Study of Normal Brain Development is a longitudinal study using anatomical MRI, diffusion tensor imaging (DTI), and MR spectroscopy (MRS) to map pediatric...

  20. Knee MRI

    ... air-conditioned and well-lit. Some scanners have music to help you pass the time. When the ... that magnetic resonance imaging harms the fetus, pregnant women usually are advised not to have an MRI ...

  1. Portable MRI

    Espy, Michelle A. [Los Alamos National Laboratory

    2012-06-29

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

  2. MRI Artifacts

    Abed Al Nasser Assi

    2009-12-01

    Full Text Available   "nMagnetic resonance imaging (MRI has become more and more frequently used in medical imaging diagnostic in recent years. Radiologists and technicians working at these systems are relatively often confronted with image artifacts related to the radiowave with strong magnetic in the scanner. Many artifacts may be corrected or modulated through an understanding of their cause. This requires familiarity with scanner design; theory of operation; and image acquisition. The purpose of this review article is to present the most relevant artifacts that arise in MRI scanner, to provide some physical background on the formation of artifacts, and to suggest strategies to reduce or avoid these artifacts. The most frequent artifacts that can occur during MRI scanning are Motion related artifacts; Para-magnetic artifacts; Phase Wrap artifacts; Frequency artifacts; Susceptibility artifacts; Clipping artefact; Chemical Shift artifact and "Zebra" artefact .    "n  

  3. MRI of congenital urethroperineal fistula

    Ghadimi-Mahani, Maryam; Dillman, Jonathan R.; Pai, Deepa; DiPietro, Michael [C. S. Mott Children' s Hospital, Department of Radiology, Section of Pediatric Radiology, University of Michigan Health System, Ann Arbor, MI (United States); Park, John [C. S. Mott Children' s Hospital, Department of Pediatric Urology, University of Michigan Health System, Ann Arbor, MI (United States)

    2010-12-15

    We present the MRI features of a congenital urethroperineal fistula diagnosed in a 12-year-old boy being evaluated after a single urinary tract infection. This diagnosis was initially suggested by voiding cystourethrogram and confirmed by MRI. Imaging revealed an abnormal fluid-filled tract arising from the posterior urethra and tracking to the perineal skin surface that increased in size during micturition. Surgical resection and histopathological evaluation of the abnormal tract confirmed the diagnosis of congenital urethroperineal fistula. MRI played important roles in confirming the diagnosis and assisting surgical planning. (orig.)

  4. Breast MRI scan

    MRI - breast; Magnetic resonance imaging - breast; Breast cancer - MRI; Breast cancer screening - MRI ... radiologist) see some areas more clearly. During the MRI, the person who operates the machine will watch ...

  5. MRI Safety during Pregnancy

    ... News Physician Resources Professions Site Index A-Z MRI Safety During Pregnancy Magnetic resonance imaging (MRI) Illness ... during the exam? Contrast material MRI during pregnancy Magnetic resonance imaging (MRI) If you are pregnant and your doctor ...

  6. MRI (Magnetic Resonance Imaging)

    ... and Procedures Medical Imaging MRI (Magnetic Resonance Imaging) MRI (Magnetic Resonance Imaging) Share Tweet Linkedin Pin it More sharing options ... usually given through an IV in the arm. MRI Research Programs at FDA Magnetic Resonance Imaging (MRI) ...

  7. Battlefield MRI

    Espy, Michelle [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-06-01

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

  8. MRI of the Chest

    Full Text Available ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Chest Magnetic resonance imaging (MRI) of the chest ... limitations of MRI of the Chest? What is MRI of the Chest? Magnetic resonance imaging (MRI) is ...

  9. Analysis on Wearable Lower Extremity Exoskeleton Gait Based on 3 D Dynamic Capture System and Matlab%基于三维动态捕捉系统和Matlab的穿戴式下肢外骨骼步态分析

    孟庆鑫; 李志瑶

    2013-01-01

    This paper obtains the trajectory and 3D datum of human lower limb key points by 3D dynamic capture system, uses Matlab software to analyze the datum, draws the time-coordinate graphics and establishes a 3D model of wearable lower limb exoskeleton, which lays a foundation for further study on wearable lower limb exoskeleton.%使用三维动态捕捉系统获取人体下肢关键点的运动轨迹和三维数据,用Matlab软件分析数据,绘制时间-坐标图形,建立穿戴式下肢外骨骼的三维模型,为进一步研究穿戴式下肢外骨骼奠定基础。

  10. Knee MRI scan

    MRI - knee ... radiologist see certain areas more clearly. During the MRI, the person who operates the machine will watch ... less anxious. Your provider may suggest an "open" MRI, in which the machine is not as close ...

  11. MRI of the Chest

    Full Text Available ... MRI of the Chest? What is MRI of the Chest? Magnetic resonance imaging (MRI) is a noninvasive ... of page What are some common uses of the procedure? MR imaging of the chest is performed ...

  12. Breast MRI used as a problem-solving tool reliably excludes malignancy

    Spick, Claudio, E-mail: claudio.spick@meduniwien.ac.at [Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna (AKH), Waehringer-Guertel 18-20, 1090 Vienna (Austria); Szolar, Dieter H.M.; Preidler, Klaus W.; Tillich, Manfred; Reittner, Pia [Diagnostikum Graz-Südwest, Weblinger Guertel 25, 8054 Graz (Austria); Baltzer, Pascal A., E-mail: pascal.baltzer@meduniwien.ac.at [Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna (AKH), Waehringer-Guertel 18-20, 1090 Vienna (Austria)

    2015-01-15

    Highlights: • Breast MRI reliably excludes malignancy in conventional BI-RADS 0 cases (NPV: 100%). • Malignancy rate in the BI-RADS 0 population is substantial with 13.5%. • Breast MRI used as a problem-solving tool reliably excludes malignancy. - Abstract: Purpose: To evaluate the diagnostic performance of breast MRI if used as a problem-solving tool in BI-RADS 0 cases. Material and methods: In this IRB-approved, single-center study, 687 women underwent high-resolution-3D, dynamic contrast-enhanced breast magnetic resonance imaging (MRI) between January 2012 and December 2012. Of these, we analyzed 111 consecutive patients (mean age, 51 ± 12 years; range, 20–83 years) categorized as BI-RADS 0. Breast MRI findings were stratified by clinical presentations, conventional imaging findings, and breast density. MRI results were compared to the reference standard, defined as histopathology or an imaging follow-up of at least 1 year. Results: One hundred eleven patients with BI-RADS 0 conventional imaging findings revealed 30 (27%) mammographic masses, 57 (51.4%) mammographic architectural distortions, five (4.5%) mammographic microcalcifications, 17 (15.3%) ultrasound-only findings, and two palpable findings without imaging correlates. There were 15 true-positive, 85 true-negative, 11 false-positive, and zero false-negative breast MRI findings, resulting in a sensitivity, specificity, PPV, and NPV of 100% (15/15), 88.5% (85/96), 57.7% (15/26), and 100% (85/85), respectively. Breast density and reasons for referral had no significant influence on the diagnostic performance of breast MRI (p > 0.05). Conclusion: Breast MRI reliably excludes malignancy in conventional BI-RADS 0 cases resulting in a NPV of 100% (85/85) and a PPV of 57.7% (15/26)

  13. Hepatocellular carcinoma: perfusion quantification with dynamic contrast-enhanced MRI

    Taouli, B.; Johnson, R.S.; Hajdu, C.H.; Oei, M.T.H.; Merad, M.; Yee, H.; Rusinek, H.

    2013-01-01

    The objective of our study was to report our initial experience with dynamic contrast-enhanced MRI (DCE-MRI) for perfusion quantification of hepatocellular carcinoma (HCC) and surrounding liver.DCE-MRI of the liver was prospectively performed on 31 patients with HCC (male-female ratio, 26:5; mean ag

  14. Animal MRI Core

    Federal Laboratory Consortium — The Animal Magnetic Resonance Imaging (MRI) Core develops and optimizes MRI methods for cardiovascular imaging of mice and rats. The Core provides imaging expertise,...

  15. Magnetic Resonance Imaging (MRI) Safety

    ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) Safety What is MRI and how does it ... and MRI Breast-feeding and MRI What is MRI and how does it work? Magnetic resonance imaging, ...

  16. Comparison of PET/CT and PET/MRI hybrid systems using a {sup 68}Ga-labelled PSMA ligand for the diagnosis of recurrent prostate cancer: initial experience

    Afshar-Oromieh, A. [University Hospital Heidelberg, Department of Nuclear Medicine, Heidelberg (Germany); German Cancer Research Center (DKFZ), Department of Radiology, Heidelberg (Germany); Haberkorn, U. [University Hospital Heidelberg, Department of Nuclear Medicine, Heidelberg (Germany); German Cancer Research Center (DKFZ), Clinical Cooperation Unit of Nuclear Medicine, Heidelberg (Germany); Schlemmer, H.P.; Fenchel, M.; Roethke, M. [German Cancer Research Center (DKFZ), Department of Radiology, Heidelberg (Germany); Eder, M.; Eisenhut, M. [German Cancer Research Center (DKFZ), Department of Radiopharmaceutical Chemistry, Heidelberg (Germany); Hadaschik, B.A. [University Hospital Heidelberg, Department of Urology, Heidelberg (Germany); Kopp-Schneider, A. [German Cancer Research Center (DKFZ), Department of Biostatistics, Heidelberg (Germany)

    2014-05-15

    {sup 68}Ga-labelled HBED-CC-PSMA is a highly promising tracer for imaging recurrent prostate cancer (PCa). The intention of this study was to evaluate the feasibility of PET/MRI with this tracer. Twenty patients underwent PET/CT 1 h after injection of the {sup 68}Ga-PSMA ligand followed by PET/MRI 3 h after injection. Data from the two investigations were first analysed separately and then compared with respect to tumour detection rate and radiotracer uptake in various tissues. To evaluate the quantification accuracy of the PET/MRI system, differences in SUVs between PET/CT and corresponding PET/MRI were compared with differences in SUVs between PET/CT 1 h and 3 h after injection in another patient cohort. This cohort was investigated using the same PET/CT system. With PET/MRI, different diagnostic sequences, higher contrast of lesions and higher resolution of MRI enabled a subjectively easier evaluation of the images. In addition, four unclear findings on PET/CT could be clarified as characteristic of PCa metastases by PET/MRI. However, in PET images of the PET/MRI, a reduced signal was observed at the level of the kidneys (in 11 patients) and around the urinary bladder (in 15 patients). This led to reduced SUVs in six lesions. SUV{sub mean} values provided by the PET/MRI system were different in muscles, blood pool, liver and spleen. PCa was detected more easily and more accurately with Ga-PSMA PET/MRI than with PET/CT and with lower radiation exposure. Consequently, this new technique could clarify unclear findings on PET/CT. However, scatter correction was challenging when the specific {sup 68}Ga-PSMA ligand was used. Moreover, direct comparison of SUVs from PET/CT and PET/MR needs to be conducted carefully. (orig.)

  17. Lagrangian structures, integrability and chaos for 3D dynamical equations

    Bustamante, M D; Bustamante, Miguel D.; Hojman, Sergio A.

    2003-01-01

    In this paper we consider the general setting for constructing Action Principles for three-dimensional first order autonomous equations. We present the results for some integrable and non-integrable cases of the Lotka-Volterra equation, and we show Lagrangian descriptions which are valid for systems satisfying Shil'nikov criteria on the existence of strange attractors, though chaotic behavior or homoclinic orbits have not been verified up to now. The Euler-Lagrange equations we get for these systems usually present "time reparameterization" symmetry, though other kinds of invariance may be found according to the kernel of the associated symplectic 2-form. The formulation of a Hamiltonian structure (Poisson brackets and Hamiltonians) for these systems from the Lagrangian viewpoint leads to a method of finding new constants of the motion starting from known ones, which is applied to some systems found in the literature known to possess a constant of the motion, to find the other and thus showing their integrabi...

  18. MRI of the lungs in children

    Hirsch, Wolfgang [Paediatric Radiology in the Department of Diagnostic and Interventional Radiology, University Hospital Leipzig (Germany)], E-mail: wolfgang.hirsch@medizin.uni-leipzig.de; Sorge, Ina; Krohmer, Svetlana; Weber, Dana [Paediatric Radiology in the Department of Diagnostic and Interventional Radiology, University Hospital Leipzig (Germany); Meier, Konstanze [Department of Paediatrics, University Hospital Leipzig (Germany); Till, Holger [Department of Paediatric Surgery, University Hospital Leipzig (Germany)

    2008-11-15

    Lung diseases of children often need diagnostic imaging beyond X-ray. Although CT is considered the gold standard of lung imaging, MRI is sufficient to answer most of the questions raised. After all, the exposure to radiation caused by one CT examination corresponds to approximately the effective dose of 200 chest radiographs. What is MRI's potential in the lung today? In diseases with alveolar pathology, cardiac- and respiratory-triggered MRI examinations are roughly equivalent to CT examinations. Distinct interstitial processes are easily diagnosable using MRI. Early interstitial processes may be missed by MRI, but conventional plain films fail to recognize them just as often. For identification of lung metastases, CT is still used as the initial diagnostic measure. Subsequent therapy monitoring may then be carried out with the help of MRI. Small bullae and pulmonary emphysema at present pose a problem to MRI. On the other hand, MRI is reliable for follow-up examinations in inflammatory diseases or for imaging of complications, and the increased use of lung MRI as an alternative to chest CT may contribute immensely to reducing radiation exposure in children.

  19. Competitive advantage of PET/MRI.

    Jadvar, Hossein; Colletti, Patrick M

    2014-01-01

    Multimodality imaging has made great strides in the imaging evaluation of patients with a variety of diseases. Positron emission tomography/computed tomography (PET/CT) is now established as the imaging modality of choice in many clinical conditions, particularly in oncology. While the initial development of combined PET/magnetic resonance imaging (PET/MRI) was in the preclinical arena, hybrid PET/MR scanners are now available for clinical use. PET/MRI combines the unique features of MRI including excellent soft tissue contrast, diffusion-weighted imaging, dynamic contrast-enhanced imaging, fMRI and other specialized sequences as well as MR spectroscopy with the quantitative physiologic information that is provided by PET. Most evidence for the potential clinical utility of PET/MRI is based on studies performed with side-by-side comparison or software-fused MRI and PET images. Data on distinctive utility of hybrid PET/MRI are rapidly emerging. There are potential competitive advantages of PET/MRI over PET/CT. In general, PET/MRI may be preferred over PET/CT where the unique features of MRI provide more robust imaging evaluation in certain clinical settings. The exact role and potential utility of simultaneous data acquisition in specific research and clinical settings will need to be defined. It may be that simultaneous PET/MRI will be best suited for clinical situations that are disease-specific, organ-specific, related to diseases of the children or in those patients undergoing repeated imaging for whom cumulative radiation dose must be kept as low as reasonably achievable. PET/MRI also offers interesting opportunities for use of dual modality probes. Upon clear definition of clinical utility, other important and practical issues related to business operational model, clinical workflow and reimbursement will also be resolved.

  20. The OMERACT MRI inflammatory arthritis group: advances and future research priorities

    Conaghan, Philip G; Bird, Paul; McQueen, Fiona;

    2009-01-01

    The OMERACT magnetic resonance imaging (MRI) in inflammatory arthritis group previously developed the rheumatoid arthritis MRI score (RAMRIS) for use in clinical studies, evaluated the use of extremity MRI, and initiated development of a psoriatic arthritis MRI score (PsAMRIS). At OMERACT 9...

  1. MRI of car occupants with whiplash injury

    Voyvodic, F. [Dept. of Radiology, Flinders Medical Centre, Bedford Park, SA (Australia); Dolinis, J. [National Injury Surveillance Unit, Bedford Park, SA (Australia)]|[National Health and Medical Research Council Road Accident Research Unit, Univ. of Adelaide, SA (Australia); Moore, V.M. [National Health and Medical Research Council Road Accident Research Unit, Univ. of Adelaide, SA (Australia); Ryan, G.A. [National Health and Medical Research Council Road Accident Research Unit, Univ. of Adelaide, SA (Australia); Slavotinek, J.P. [Dept. of Radiology, Flinders Medical Centre, Bedford Park, SA (Australia); Whyte, A.M. [Ashford Hospital Specialist Centre, SA (Australia); Hoile, R.D. [Ashford Hospital Specialist Centre, SA (Australia); Taylor, G.W. [National Health and Medical Research Council Road Accident Research Unit, Univ. of Adelaide, SA (Australia)

    1997-01-01

    Our purpose was to document and investigate the prognostic significance of features seen on MRI of patients with whiplash injury following relatively minor road traffic crashes. MRI was obtained shortly and at 6 months after the crash using a 0.5 T imager. The images were assessed independently by two radiologists for evidence of fracture or other injury; loss of lordosis and spondylosis were also recorded. Clinical examinations were used to assess the status of patients initially and at 6 months. The results of the independent MRI and clinical investigations were then examined for association using statistical tests. Initial MRI was performed on 29 patients, of whom 19 had repeat studies at 6 months; 48 examinations were thus examined. Apart from spondylosis and loss of lordosis, only one abnormality was detected: an intramedullary lesion consistent with a small cyst or syrinx. There were no statistically significant associations between the outcome of injury and spondylosis or loss of lordosis. No significant changes were found when comparing the initial and follow-up MRI. It appears that MRI of patients with relatively less severe whiplash symptoms reveals a low frequency of abnormalities, apart from spondylosis and loss of lordosis, which have little short-term prognostic value. Routine investigation of such patients with MRI is not justified in view of the infrequency of abnormalities detected, the lack of prognostic value and the high cost of the procedure. (orig.). With 1 fig., 1 tab.

  2. Initial clinical results of simultaneous {sup 18}F-FDG PET/MRI in comparison to {sup 18}F-FDG PET/CT in patients with head and neck cancer

    Kubiessa, K.; Gawlitza, M.; Kuehn, A.; Fuchs, J.; Kahn, T.; Stumpp, P. [University Hospital of Leipzig, Department of Diagnostic and Interventional Radiology, Leipzig (Germany); Purz, S.; Steinhoff, K.G.; Sabri, O.; Kluge, R. [University Hospital of Leipzig, Department of Nuclear Medicine, Leipzig (Germany); Boehm, A. [University Hospital of Leipzig, ENT Department, Leipzig (Germany)

    2014-04-15

    The aim of this study was to evaluate the diagnostic capability of simultaneous {sup 18}F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/MRI compared to {sup 18}F-FDG PET/CT as well as their single components in head and neck cancer patients. In a prospective study 17 patients underwent {sup 18}F-FDG PET/CT for staging or follow-up and an additional {sup 18}F-FDG PET/MRI scan with whole-body imaging and dedicated examination of the neck. MRI, CT and PET images as well as PET/MRI and PET/CT examinations were evaluated independently and in a blinded fashion by two reader groups. Results were compared with the reference standard (final diagnosis determined in consensus using all available data including histology and follow-up). Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated. A total of 23 malignant tumours were found with the reference standard. PET/CT showed a sensitivity of 82.7 %, a specificity of 87.3 %, a PPV of 73.2 % and a NPV of 92.4 %. Corresponding values for PET/MRI were 80.5, 88.2, 75.6 and 92.5 %. No statistically significant difference in diagnostic capability could be found between PET/CT and PET/MRI. Evaluation of the PET part from PET/CT revealed highest sensitivity of 95.7 %, and MRI showed best specificity of 96.4 %. There was a high inter-rater agreement in all modalities (Cohen's kappa 0.61-0.82). PET/MRI of patients with head and neck cancer yielded good diagnostic capability, similar to PET/CT. Further studies on larger cohorts to prove these first results seem justified. (orig.)

  3. Validation of Continuously Tagged MRI for the Measurement of Dynamic 3D Skeletal Muscle Tissue Deformation

    Moerman, Kevin M; Simms, Ciaran K; Lamerichs, Rolf M; Stoker, Jaap; Nederveen, Aart J

    2016-01-01

    A SPAMM tagged MRI methodology is presented allowing continuous (3.3-3.6 Hz) sampling of 3D dynamic soft tissue deformation using non-segmented 3D acquisitions. The 3D deformation is reconstructed by the combination of 3 mutually orthogonal tagging directions, thus requiring only 3 repeated motion cycles. In addition a fully automatic post-processing framework is presented employing Gabor scale-space and filter-bank analysis for tag extrema segmentation and triangulated surface fitting aided by Gabor filter bank derived surface normals. Deformation is derived following tracking of tag surface triplet triangle intersections. The dynamic deformation measurements were validated using indentation tests (~20 mm deep at 12 mm/s) on a silicone gel soft tissue phantom containing contrasting markers which provide a reference measure of deformation. In addition, the techniques were evaluated in-vivo for dynamic skeletal muscle tissue deformation measurement during indentation of the biceps region of the upper arm in a ...

  4. MRI of the Chest

    Full Text Available ... is done because a potential abnormality needs further evaluation with additional views or a special imaging technique. ... MRI an invaluable tool in early diagnosis and evaluation of cardiovascular conditions. MRI has proven valuable in ...

  5. MRI of the Chest

    Full Text Available ... MRI. If you have claustrophobia (fear of enclosed spaces) or anxiety, you may want to ask your ... or headphones during the exam. MRI scanners are air-conditioned and well-lit. Music may be played ...

  6. Abdominal MRI scan

    Nuclear magnetic resonance - abdomen; NMR - abdomen; Magnetic resonance imaging - abdomen; MRI of the abdomen ... radiologist see certain areas more clearly. During the MRI, the person who operates the machine will watch ...

  7. MRI of the Chest

    Full Text Available ... have this exam in the first trimester of pregnancy unless the potential benefit from the MRI exam ... See the Safety page for more information about pregnancy and MRI. If you have claustrophobia (fear of ...

  8. MRI of the Chest

    Full Text Available ... 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 ...

  9. MRI of the Chest

    ... 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 ...

  10. Neurosarcoidosis with unusual MRI findings

    Handler, M.S. (Dept. of Pathology and Oncology, Kansas Univ. Medical Center, KS (United States)); Johnson, L.M. (Dept. of Neurology, Kansas Univ. Medical Center, KS (United States)); Dick, A.R. (Dept. of Neurology, Kansas Univ. Medical Center, KS (United States)); Batnitzky, S. (Dept. of Diagnostic Radiology, Kansas Univ. Medical Center, KS (United States))

    1993-02-01

    This 53-year-old white male presented with a 4-month-history of weakness and pain. Despite an initial partial response to steroid therapy, his neurologic deterioration progressed culminating in paraparesis, paresthesias, urinary incontinence, altered mentation and a 20 Ib weight loss. A gadolinium-enhanced MRI study showed a pattern suggestive of perivascular involvement. A subsequent cerebral biopsy was diagnostic for neurosarcoidosis. (orig.)

  11. Improved visualization of delayed perfusion in lung MRI

    Risse, Frank [Department of Medical Physics in Radiology, German Cancer Research Center, Heidelberg (Germany); Eichinger, Monika [Department of Radiology, German Cancer Research Center, Heidelberg (Germany); Kauczor, Hans-Ulrich [Department of Diagnostic and Interventional Radiology, University Hospital Heidelberg, Heidelberg (Germany); Semmler, Wolfhard [Department of Medical Physics in Radiology, German Cancer Research Center, Heidelberg (Germany); Puderbach, Michael, E-mail: m.puderbach@dkfz.de [Department of Radiology, German Cancer Research Center, Heidelberg (Germany)

    2011-01-15

    Introduction: The investigation of pulmonary perfusion by three-dimensional (3D) dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) was proposed recently. Subtraction images are generated for clinical evaluation, but temporal information is lost and perfusion defects might therefore be masked in this process. The aim of this study is to demonstrate a simple analysis strategy and classification for 3D-DCE-MRI perfusion datasets in the lung without omitting the temporal information. Materials and methods: Pulmonary perfusion measurements were performed in patients with different lung diseases using a 1.5 T MR-scanner with a time-resolved 3D-GRE pulse sequence. 25 3D-volumes were acquired after iv-injection of 0.1 mmol/kg KG Gadolinium-DTPA. Three parameters were determined for each pixel: (1) peak enhancement S{sub n,max} normalized to the arterial input function to detect regions of reduced perfusion; (2) time between arterial peak enhancement in the large pulmonary artery and tissue peak enhancement {tau} to visualize regions with delayed bolus onset; and (3) ratio R = S{sub n,max}/{tau} was calculated to visualize impaired perfusion, irrespectively of whether related to reduced or delayed perfusion. Results: A manual selection of peak perfusion images is not required. Five different types of perfusion can be found: (1) normal perfusion; (2) delayed non-reduced perfusion; (3) reduced non-delayed perfusion; (4) reduced and delayed perfusion; and (5) no perfusion. Types II and IV could not be seen in subtraction images since the temporal information is necessary for this purpose. Conclusions: The analysis strategy in this study allows for a simple and observer-independent visualization and classification of impaired perfusion in dynamic contrast-enhanced pulmonary perfusion MRI by using the temporal information of the datasets.

  12. fMRI Neuroinformatics

    Nielsen, Finn Årup; Christensen, Mark Schram; Madsen, Kristoffer M.

    2006-01-01

    Functional magnetic resonance imaging (fMRI) generates vast amounts of data. The handling, processing, and analysis of fMRI data would be inconceivable without computer-based methods. fMRI neuroinformatics is concerned with research, development, and operation of these methods. Reconstruction...

  13. MRI in acute poliomyelitis

    Kornreich, L. [Imaging Department, The Schneider Children`s Medical Centre of Israel, Kaplan Street, Petah Tiqva 49202 (Israel)]|[Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv (Israel); Dagan, O. [The Intensive Care Unit, The Schneider Children`s Medical Centre of Israel, Beilinson Medical Campus, Petah Tiqva (Israel)]|[Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv (Israel); Grunebaum, M. [Imaging Department, The Schneider Children`s Medical Centre of Israel, Kaplan Street, Petah Tiqva 49202 (Israel)]|[Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv (Israel)

    1996-05-01

    MRI can be used in the diagnosis of anterior horn infection and for assessing the extent of disease. There are no specific MRI signs to differentiate between the various possible pathogens. This is demonstrated in the present case of poliomyelitis, in which MRI of the spine played an important role in establishing the diagnosis. (orig.). With 1 fig.

  14. MRI of radiographically occult ischial apophyseal avulsions

    Meyers, Arthur B. [Cincinnati Children' s Hospital Medical Center, Department of Radiology, MLC 5031, Cincinnati, OH (United States); Children' s Hospital of Wisconsin, Milwaukee, WI (United States); Laor, Tal; Zbojniewicz, Andrew M.; Anton, Christopher G. [Cincinnati Children' s Hospital Medical Center, Department of Radiology, MLC 5031, Cincinnati, OH (United States)

    2012-11-15

    Acute avulsions of unossified ischial apophyses in children may go undetected on radiography. Therapy includes rest and rehabilitation; however, substantial displacement may require surgery. Our purpose is to illustrate the utility of MRI in the detection of these radiographically occult injuries in skeletally immature children. This retrospective study of more than 5 years included children with ischial avulsions who were evaluated with both radiography and MRI within 3 weeks of acute injury. Initially, radiographs were reviewed to identify those children with unossified ischial apophyses. Subsequently, their MRI examinations were assessed for physeal disruption, bone/soft tissue edema, periosteal/perichondrial elevation and disruption. Initial and follow-up radiographs (if available) were reviewed. Patient age, symptoms and offending activity were determined from clinical records. Five children met inclusion criteria. All initial radiographs were normal. MRI showed: edema (n = 5), periosteal elevation (n = 4), periosteal/perichondrial disruption (n = 4), >5.5 mm displacement (n = 0). Follow-up radiographs in two children (2 and 2.5 months from MRI) showed osseous ischial irregularity. The apophyses remained unossified. Acute unossified ischial apophyseal avulsions in children may be radiographically undetected. In the setting of correlative clinical symptoms, MRI can be used to identify these injuries and to help direct appropriate therapy. (orig.)

  15. MRI in psychiatry

    Mulert, Christoph [UKE, Hamburg (Germany). Psychiatry Neuroimaging Branch; Shenton, Martha E. (ed.) [Harvard Medical School, Boston, MA (United States). Dept. of Psychiatry and Radiology

    2014-07-01

    This is the first comprehensive textbook on the use of MRI in psychiatry covering imaging techniques, brain systems and a review of findings in different psychiatric disorders. The book is divided into three sections, the first of which covers in detail all the major MRI-based methodological approaches available today, including fMRI, EEG-fMRI, DTI, and MR spectroscopy. In addition, the role of MRI in imaging genetics and combined brain stimulation and imaging is carefully explained. The second section provides an overview of the different brain systems that are relevant for psychiatric disorders, including the systems for perception, emotion, cognition, and reward. The final part of the book presents the MRI findings that are obtained in all the major psychiatric disorders using the previously discussed techniques. Numerous carefully chosen images support the informative text, making this an ideal reference work for all practitioners and trainees with an interest in this flourishing field.

  16. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Head Magnetic resonance imaging (MRI) of the head ... limitations of MRI of the Head? What is MRI of the Head? Magnetic resonance imaging (MRI) is ...

  17. MRI brain imaging.

    Skinner, Sarah

    2013-11-01

    General practitioners (GPs) are expected to be allowed to request MRI scans for adults for selected clinically appropriate indications from November 2013 as part of the expansion of Medicare-funded MRI services announced by the Federal Government in 2011. This article aims to give a brief overview of MRI brain imaging relevant to GPs, which will facilitate explanation of scan findings and management planning with their patients. Basic imaging techniques, common findings and terminology are presented using some illustrative case examples.

  18. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... information on the chemicals present in the body's cells, may also be performed during the MRI exam ... medically necessary. MRI may not always distinguish between cancer tissue and fluid, known as edema . MRI typically ...

  19. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... MRI of the Head? What is MRI of the Head? Magnetic resonance imaging (MRI) is a noninvasive ... of page What are some common uses of the procedure? MR imaging of the head is performed ...

  20. The Management of Benign Concordant MRI-guided Brest Biopsies: Lessons Learned.

    Lee, Su-Ju; Mahoney, Mary C; Redus, Zachary

    2015-01-01

    After benign concordant magnetic resonance imaging (MRI)-guided breast biopsy, initial follow-up MRI at 6 months is often recommended for confirmation. This study was undertaken to determine the proper management of stable lesions on initial follow-up MRI and whether such follow-up can be safely deferred to 12 months. Retrospective review of 240 MRI-guided biopsies identified 156 benign concordant lesions. 85 eligible cases received follow-up MRI and constitute the study population. On initial follow-up MRI, 72 of 85 lesions appeared adequately sampled, 12 were stable and underwent further MRI follow-up, and 1 was benign on subsequent surgery. No cancers were diagnosed at the biopsy sites on either 6- or 12-month follow-up MRI. Among the 12 stable lesions, four were masses and eight were nonmass enhancements. One of the stable masses enlarged on 24-month follow-up MRI and proved malignant. All stable nonmass lesions were benign on long-term follow-up. After benign concordant MRI-guided breast biopsy, a stable mass has a 25% probability of malignancy in our series. Re-biopsy of such masses should be strongly considered. Stable nonmass lesions may be followed with subsequent MRI without rebiopsy. Deferral of initial follow-up MRI to 12 months may be acceptable.

  1. Metastasis in the base of the cranium: initial manifestation of a hepato carcinoma. Findings in the CT and MRI; Metastasis en la base del carneo: manifestacion inicial de un hepatocarcinoma. Hallazgos en TC y RM

    Fernandez, M. T.; Saiz, A.; Cardenal, A.; Oruezabal, M. [Hospital Clinico San Carlos. Madrid (Spain)

    2000-07-01

    We present a case of hepato carcinoma (HC) whose first clinical manifestation was diplopia. The imaging methods showed a sold mass in the base of the cranium with meningioma characteristics. The histological study showed the existence of hepatocytes, which confirmed the diagnosis of metastasis of the HC: We present the X-ray findings in the CT and MRI of this case and the differential diagnosis with other tumors that affect the cranium base. We also perform a bibliographic review of this clinical manifestation with such an unusual X-ray. (Author) 19 refs.

  2. Initial results using MRI-guided laser-induced interstitial thermotherapy for head and neck tumors; Erste Ergebnisse der MRT-gesteuerten laserinduzierten interstitiellen Thermotherapie von Kopf- und Halstumoren

    Jaeger, L. [Inst. fuer Radiologische Diagnostik, Klinikum Grosshadern der Ludwig-Maximilians-Universitaet, Muenchen (Germany); Mueller-Lisse, G.U. [Inst. fuer Radiologische Diagnostik, Klinikum Grosshadern der Ludwig-Maximilians-Universitaet, Muenchen (Germany); Gutmann, R. [Klinikum und Poliklinik fuer Hals-, Nasen- und Ohrenkranke, Klinikum Grasshadern der Ludwig-Maximilians-Universitaet, Muenchen (Germany); Feyh, J. [Klinikum und Poliklinik fuer Hals-, Nasen- und Ohrenkranke, Klinikum Grasshadern der Ludwig-Maximilians-Universitaet, Muenchen (Germany); Thoma, M. [Inst. fuer Radiologische Diagnostik, Klinikum Grosshadern der Ludwig-Maximilians-Universitaet, Muenchen (Germany); Reiser, M. [Inst. fuer Radiologische Diagnostik, Klinikum Grosshadern der Ludwig-Maximilians-Universitaet, Muenchen (Germany)

    1996-03-01

    Laser-induced interstitial thermotherapy (LITT) was introduced as a minimally invasive form of therapy for tumors in different anatomic regions. However, in the orofacial region, it has not been used so far for inoperable T4 carcinomas. Since vascular and neural structures are often close to the tumor or are even involved, online monitoring of LITT is necessary. The aim of our study was to establish a method of monitoring LITT with MRI (magnetic resonance imaging) in the orofacial region. Five patients with T4 carcinomas of the orofacial region underwent LITT under anesthesia. A 1.5 T wholebody imager with a circulary polarized head coild was used. Before and after the intervention, the region of interest was studied using T1- and T2-weighted sequences in axial and coronal planes, with and without contrast enhancement (intravenous Gd-DTPA). Temperature distribution was monitored with a T1-weighted 2D-FLASH (fast low angle shot) sequence. The positioning of the optical fibers was monitored with MRI. Nd:YAG laser equipment was used for laser application. The necrosis was best seen on contrast-enhanced MRI. Immediately after LITT, the outcome could be determined by MRI. We proposed that MRI-guided LITT be used for neoplasma in the orofacial region at advanced stages. (orig.) [Deutsch] Als neues minimalinvasives Verfahren wird die laserinduzierte interstitielle Thermotherapie (LITT) zunehmend bei tumoroesen Raumforderungen eingesetzt. In der Therapie von ausgedehnten Tumoren der Orofazialregion liegen bisher keine Erfahrungen vor. Die anatomische Komplexitaet dieser Region mit eng benachbarten vaskulaeren und nervalen Strukturen, an die meist der Tumor reicht, erlaubt keine Eingriffe ohne eine kontinuierliche Ueberwachung. Ziel unserer Untersuchungen war die Etablierung einer LITT von ausgedehnten inoperablen Kopf- und Halstumoren unter MRT-(Magnetresonanztomographie-)Kontrolle. Die Untersuchungen wurden an einem 1,5-T-Ganzkoerpertomographen, unter Verwendung einer

  3. Ultrasound- and MRI-Guided Prostate Biopsy

    ... Resources Professions Site Index A-Z Ultrasound- and MRI-Guided Prostate Biopsy Ultrasound- and MRI-guided prostate ... MRI-guided Prostate Biopsy? What is Ultrasound- and MRI-guided Prostate Biopsy? Ultrasound- and MRI-guided prostate ...

  4. Ultrasound- and MRI-Guided Prostate Biopsy

    ... News Physician Resources Professions Site Index A-Z Ultrasound- and MRI-Guided Prostate Biopsy Ultrasound- and MRI- ... Ultrasound-and MRI-guided Prostate Biopsy? What is Ultrasound- and MRI-guided Prostate Biopsy? Ultrasound- and MRI- ...

  5. MRI in perianal fistulae

    Khera Pushpinder

    2010-01-01

    Full Text Available MRI has become the method of choice for evaluating perianal fistulae due to its ability to display the anatomy of the sphincter muscles orthogonally, with good contrast resolution. In this article we give an outline of the classification of perianal fistulae and present a pictorial assay of sphincter anatomy and the MRI findings in perianal fistulae. This study is based on a retrospective analysis of 43 patients with a clinical diagnosis of perianal fistula. MRI revealed a total of 44 fistulae in 35 patients; eight patients had only perianal sinuses.

  6. Brain MRI in Parkinson's disease

    Meijer, F.J.A.; Goraj, B.M.

    2014-01-01

    In this review article, conventional brain MRI and advanced MRI techniques in Parkinson`s disease (PD) are discussed, with emphasis on clinical relevance. Conventional brain MRI sequences generally demonstrate limited abnormalities specific for PD and in clinical practice brain MRI is mainly used to

  7. New method for 3D parametric visualization of contrast-enhanced pulmonary perfusion MRI data

    Kuder, Tristan A.; Eichinger, Monika; Ley, Sebastian; Puderbach, Michael; Kauczor, Hans-Ulrich [Deutsches Krebsforschungszentrum, Department of Radiology, E010, Heidelberg (Germany); Risse, Frank [Deutsches Krebsforschungszentrum, Department of Medical Physics in Radiology, Heidelberg (Germany); Fink, Christian [Deutsches Krebsforschungszentrum, Department of Radiology, E010, Heidelberg (Germany); Medical Faculty Mannheim - University of Heidelberg, Department of Clinical Radiology, University Hospital Mannheim, Mannheim (Germany)

    2008-02-15

    Three-dimensional (3D) dynamic contrast-enhanced magnetic resonance imaging (3D DCE-MRI) has been proposed for the assessment of regional perfusion. The aim of this work was the implementation of an algorithm for a 3D parametric visualization of lung perfusion using different cutting planes and volume rendering. Our implementation was based on 3D DCE-MRI data of the lungs of five patients and five healthy volunteers. Using the indicator dilution theory, the regional perfusion parameters, tissue blood flow, blood volume and mean transit time were calculated. Due to the required temporal resolution, the volume elements of dynamic MR data sets show a reduced spatial resolution in the z-direction. Therefore, perfusion parameter volumes were interpolated. Linear interpolation and a combination of linear and nearest-neighbor interpolation were evaluated. Additionally, ray tracing was applied for 3D visualization. The linear interpolation algorithm caused interpolation errors at the lung borders. Using the combined interpolation, visualization of perfusion information in arbitrary cutting planes and in 3D using volume rendering was possible. This facilitated the localization of perfusion deficits compared with the coronal orientated source data. The 3D visualization of perfusion parameters using a combined interpolation algorithm is feasible. Further studies are required to evaluate the additional benefit from the 3D visualization. (orig.)

  8. Semi-automatic segmentation for 3D motion analysis of the tongue with dynamic MRI.

    Lee, Junghoon; Woo, Jonghye; Xing, Fangxu; Murano, Emi Z; Stone, Maureen; Prince, Jerry L

    2014-12-01

    Dynamic MRI has been widely used to track the motion of the tongue and measure its internal deformation during speech and swallowing. Accurate segmentation of the tongue is a prerequisite step to define the target boundary and constrain the tracking to tissue points within the tongue. Segmentation of 2D slices or 3D volumes is challenging because of the large number of slices and time frames involved in the segmentation, as well as the incorporation of numerous local deformations that occur throughout the tongue during motion. In this paper, we propose a semi-automatic approach to segment 3D dynamic MRI of the tongue. The algorithm steps include seeding a few slices at one time frame, propagating seeds to the same slices at different time frames using deformable registration, and random walker segmentation based on these seed positions. This method was validated on the tongue of five normal subjects carrying out the same speech task with multi-slice 2D dynamic cine-MR images obtained at three orthogonal orientations and 26 time frames. The resulting semi-automatic segmentations of a total of 130 volumes showed an average dice similarity coefficient (DSC) score of 0.92 with less segmented volume variability between time frames than in manual segmentations.

  9. Clinical evaluation of 3D/3D MRI-CBCT automatching on brain tumors for online patient setup verification - A step towards MRI-based treatment planning

    Buhl, Sune K.; Duun-Christensen, Anne Katrine; Kristensen, Brian H.

    2010-01-01

    Background. Magnetic Resonance Imaging (MRI) is often used in modern day radiotherapy (RT) due to superior soft tissue contrast. However, treatment planning based solely on MRI is restricted due to e. g. the limitations of conducting online patient setup verification using MRI as reference....... In this study 3D/3D MRI-Cone Beam CT (CBCT) automatching for online patient setup verification was investigated. Material and methods. Initially, a multi-modality phantom was constructed and used for a quantitative comparison of CT-CBCT and MRI-CBCT automatching. Following the phantom experiment three patients...

  10. MRI of the Chest

    Full Text Available ... information on the chemicals present in the body's cells, may also be performed during the MRI exam ... in diagnosing a broad range of conditions, including cancer, heart and vascular disease, heart valve abnormalities, bone ...

  11. MRI of the Chest

    Full Text Available ... provides movie-like sequential imaging of the cardiovascular system that is important to assess the health and ... the magnet. Some MRI units, called short-bore systems , are designed so that the magnet does not ...

  12. MRI of the Chest

    Full Text Available ... magnetic field is produced by passing an electric current through wire coils in most MRI units. Other ... that are detected by the coils. The electric current does not come in contact with the patient. ...

  13. MRI of the Chest

    ... surgery pose no risk during MRI. However, a recently placed artificial joint may require the use of ... evaluation with additional views or a special imaging technique. A follow-up examination may also be necessary ...

  14. MRI of the Breast

    ... surgery pose no risk during MRI. However, a recently placed artificial joint may require the use of ... evaluation with additional views or a special imaging technique. A follow-up examination may also be necessary ...

  15. Combined PET/MRI

    Bailey, D. L.; Pichler, B. J.; Gückel, B.;

    2015-01-01

    This paper summarises key themes and discussions from the 4th international workshop dedicated to the advancement of the technical, scientific and clinical applications of combined positron emission tomography (PET)/magnetic resonance imaging (MRI) systems that was held in Tübingen, Germany, from...... February 23 to 27, 2015. Specifically, we summarise the three days of invited presentations from active researchers in this and associated fields augmented by round table discussions and dialogue boards with specific topics. These include the use of PET/MRI in cardiovascular disease, paediatrics, oncology......, neurology and multi-parametric imaging, the latter of which was suggested as a key promoting factor for the wider adoption of integrated PET/MRI. Discussions throughout the workshop and a poll taken on the final day demonstrated that attendees felt more strongly that PET/MRI has further advanced in both...

  16. MRI of the Chest

    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 ...

  17. MRI of the Chest

    Full Text Available ... tissue and fluid, known as edema . MRI typically costs more and may take more time to perform ... accredited facilities database . This website does not provide cost information. The costs for specific medical imaging tests, ...

  18. Extradural spinal meningioma: MRI

    Sato, N. [Department of Diagnostic Radiology, Yale University School of Medicine, P. O. Box 20 8042, New Haven, CT 06520-8042 (United States); Sze, G. [Department of Diagnostic Radiology, Yale University School of Medicine, P. O. Box 20 8042, New Haven, CT 06520-8042 (United States)

    1997-06-01

    We report a case of extradural spinal meningioma with pathologically proven features of malignant transformation. The MRI findings of extradural spinal meningioma and differences in the findings from intradural meningiomas are discussed. (orig.). With 1 fig.

  19. MRI of the Chest

    Full Text Available ... of the chest uses a powerful magnetic field, radio waves and a computer to produce detailed pictures ... medical conditions. MRI uses a powerful magnetic field, radio frequency pulses and a computer to produce detailed ...

  20. MRI of the Chest

    Full Text Available ... any recent surgeries. Some conditions, such as severe kidney disease, may prevent you from being given gadolinium contrast ... an MRI. If you have a history of kidney disease or liver transplant, it will be necessary to ...

  1. MRI of the Chest

    Full Text Available ... intercom. Many MRI centers allow a friend or parent to stay in the room as long as they are also screened for safety in the magnetic environment. Children will be given appropriately sized earplugs or headphones ...

  2. MRI of the Chest

    Full Text Available ... scanner. top of page How does the procedure work? Unlike conventional x-ray examinations and computed tomography ( ... clearer and more detailed than with other imaging methods. This detail makes MRI an invaluable tool in ...

  3. MRI of the Chest

    Full Text Available ... may follow your regular daily routine and take food and medications as usual. Some MRI examinations may ... to iodine or x-ray contrast material, drugs, food, or the environment, or if you have asthma. ...

  4. MRI of the Chest

    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 ...

  5. MRI of the Chest

    Full Text Available ... magnetic field of the MRI unit, metal and electronic items are not allowed in the exam room. ... tell the technologist if you have medical or electronic devices in your body. These objects may interfere ...

  6. MRI of the Chest

    Full Text Available ... contrast for an MRI. If you have a history of kidney disease or liver transplant, it will ... Radiology (ACR) and the Radiological Society of North America (RSNA), comprising physicians with expertise in several radiologic ...

  7. MRI of the Chest

    Full Text Available ... Unless you are told otherwise, take your regular medications as usual. Leave jewelry at home and wear ... your regular daily routine and take food and medications as usual. Some MRI examinations may require you ...

  8. MRI of plantar fasciitis

    Roger, B.; Grenier, P. [Service de Radiologie Polyvalente Diagnostique et Interventionelle, Hopital de la Pitie, 83, boulevard de l`Hopital, F-75651 Paris Cedex 13 (France)

    1997-12-01

    At present, MRI is the only imaging method that can precisely visualize lesions of the superficial plantar aponeurosis, whether they be musculoaponeurositides, enthesopathies or tears, and whether they be acute or chronic, with or without complications. By its direct visualization of the lesion, MRI enables an accurate assessment of the injury to be made and thereby better orients the therapeutic strategy. (orig.) With 11 figs., 15 refs.

  9. Posttraumatic pseudolipoma: MRI appearances

    Theumann, N.; Abdelmoumene, A.; Wintermark, M.; Schnyder, P.; Gailloud, M.C.; Resnick, D. [CHUV, Department of Diagnostic and Interventional Radiology, Lausanne (Switzerland)

    2005-09-01

    The goal of this study was to describe the MRI characteristics of posttraumatic pseudolipomas. Ten patients with previous history of blunt trauma or local surgery were investigated with MRI at the level of their deformity. The etiology was blunt trauma in eight patients and postoperative trauma in two. For all patients medical documentation, in the form of clinical history and physical examination, confirmed that a visible hematoma was present acutely at the same location following the injury and that the contour deformity subsequently appeared. All patients underwent liposuction. Preoperative bilateral MRI examinations were performed on all patients. The mean clinical follow-up was 17.8 months. MRI examinations were interpreted in consensus by two experienced musculoskeletal radiologists with attention to fatty extension (subcutaneous fatty thickness and anatomical extension), asymmetry compared with the asymptomatic side, the presence or absence of fibrous septae or nonfatty components, and patterns of contrast enhancement. Ten posttraumatic pseudolipomas were identified. Clinically, they showed as subcutaneous masses with the consistency of normal adipose tissue. Their locations were the abdomen (n=1), hip (n=1), the upper thigh (n=6), the knee (n=1), and the ankle (n=1). On MRI examinations, using the contralateral side as a control, pseudolipomas appeared as focal fatty masses without a capsule or contrast enhancement. Posttraumatic pseudolipomas may develop at a site of blunt trauma or surgical procedures often antedated by a soft tissue hematoma. Characteristic MRI findings are unencapsulated subcutaneous fatty masses without contrast enhancement. (orig.)

  10. Fetal MRI in experimental tracheal occlusion

    Wedegaertner, Ulrike [Department of Diagnostic and Interventional Radiology, Universitaetsklinikum Hamburg-Eppendorf, Martinistrasse 52, 20251 Hamburg (Germany)]. E-mail: wedegaer@uke.uni-hamburg.de; Schroeder, Hobe J. [Experimental Gynecology, Department of Obstetrics and Prenatal Medicine, Universitaetsklinikum Hamburg-Eppendorf, Hamburg (Germany); Adam, Gerhard [Department of Diagnostic and Interventional Radiology, Universitaetsklinikum Hamburg-Eppendorf, Hamburg (Germany)

    2006-02-15

    Congenital diaphragmatic hernia (CDH) is associated with a high mortality, which is mainly due to pulmonary hypoplasia and secondary pulmonary hypertension. In severely affected fetuses, tracheal occlusion (TO) is performed prenatally to reverse pulmonary hypoplasia, because TO leads to accelerated lung growth. Prenatal imaging is important to identify fetuses with pulmonary hypoplasia, to diagnose high-risk fetuses who would benefit from TO, and to monitor the effect of TO after surgery. In fetal imaging, ultrasound (US) is the method of choice, because it is widely available, less expensive, and less time-consuming to perform than magnetic resonance imaging (MRI). However, there are some limitations for US in the evaluation of CDH fetuses. In those cases, MRI is helpful because of a better tissue contrast between liver and lung, which enables evaluation of liver herniation for the diagnosis of a high-risk fetus. MRI provides the ability to determine absolute lung volumes to detect lung hypoplasia. In fetal sheep with normal and hyperplastic lungs after TO, lung growth was assessed on the basis of cross-sectional US measurements, after initial lung volume determination by MRI. To monitor fetal lung growth after prenatal TO, both MRI and US seem to be useful methods.

  11. Initial study of functional MRI on self-focused attention in depression patients%抑郁患者自我注意的功能性MRI初步探讨

    董海波; 马晓洁; 陈传锋; 李亚迪

    2013-01-01

    目的:研究抑郁患者自我注意的大脑皮层功能变化,探讨自我注意是否与抑郁情绪相关.方法:选取8名抑郁患者和9名健康志愿者进行fMRI.采用BOLD组块设计,受试者接受与自我注意相关的3种任务刺激,原始数据经SPM8脑功能MR软件包处理,获得受试者的脑激活图,并进行对照研究,分析抑郁患者和健康志愿者脑激活空间分布的差异.结果:三种靶刺激条件下,抑郁患者比正常志愿者均存在较多激活脑区.抑郁患者在“我”靶刺激条件下脑区激活显著多于“*”和“他”靶刺激条件.结论:抑郁患者可能存在自我注意偏向,抑郁情绪可能与自我注意相关.%Objective:To explore the cerelral activation of depression patients when performing self-focused attention tasks and the correlation between self-focused attention and depression.Methods:Eight depressive patients and nine healthy volunteers underwent fMRI scan using three self-focused attentional patterns stimulus in a block design,SPM8 software was used for image data processing.Comparative brain activation maps between depression patients and healthy volunteers were carried out.Results:The active areas of depressive patients are more extensive than that of healthy volunteers in three target stimulus conditions.For the depressed patients,the active areas in the "Ⅰ" target stimulus conditions are more extensive than that of "He" and "*" conditions.Conclusion:Depressive patients may have self-focused attentional bias,self-focused attention might be associated with depression.

  12. Applications of arterial spin labeled MRI in the brain.

    Detre, John A; Rao, Hengyi; Wang, Danny J J; Chen, Yu Fen; Wang, Ze

    2012-05-01

    Perfusion provides oxygen and nutrients to tissues and is closely tied to tissue function while disorders of perfusion are major sources of medical morbidity and mortality. It has been almost two decades since the use of arterial spin labeling (ASL) for noninvasive perfusion imaging was first reported. While initial ASL magnetic resonance imaging (MRI) studies focused primarily on technological development and validation, a number of robust ASL implementations have emerged, and ASL MRI is now also available commercially on several platforms. As a result, basic science and clinical applications of ASL MRI have begun to proliferate. Although ASL MRI can be carried out in any organ, most studies to date have focused on the brain. This review covers selected research and clinical applications of ASL MRI in the brain to illustrate its potential in both neuroscience research and clinical care.

  13. Contrast Enhanced MRI in the Diagnosis of HCC

    Eric Niendorf

    2015-09-01

    Full Text Available Hepatocellular carcinoma (HCC is the 6th most common cancer worldwide. Imaging plays a critical role in HCC screening and diagnosis. Initial screening of patients at risk for HCC is performed with ultrasound. Confirmation of HCC can then be obtained by Computed Tomography (CT or Magnetic Resonance Imaging (MRI, due to the relatively high specificity of both techniques. This article will focus on reviewing MRI techniques for imaging HCC, felt by many to be the exam of choice for HCC diagnosis. MRI relies heavily upon the use of gadolinium-based contrast agents and while primarily extracellular gadolinium-based contrast agents are used, there is an emerging role of hepatobiliary contrast agents in HCC imaging. The use of other non-contrast enhanced MRI techniques for assessing HCC will also be discussed and these MRI strategies will be reviewed in the context of the pathophysiology of HCC to help understand the MR imaging appearance of HCC.

  14. No erosive progression revealed by MRI in rheumatoid arthritis patients treated with etanercept, even in patients with persistent MRI and clinical signs of joint inflammation

    Døhn, Uffe Møller; Skjødt, Henrik; Hetland, Merete;

    2007-01-01

    The aim of this study is to investigate the course of magnetic resonance imaging (MRI) signs of inflammatory and destructive changes in rheumatoid arthritis (RA) wrist and metacarpophalangeal (MCP) joints during etanercept treatment. MRI of the non-dominant wrist and second to fifth MCP joints...... was performed in five clinical active RA patients before and 4 and 16 weeks after initiation of etanercept treatment. MRI was evaluated according to the EULAR-OMERACT RA MRI reference image atlas. The median 28-joint count disease activity score (DAS28; erythrocyte sedimentation rate based) was 5.6 (range 5...... patient showed erosive regression, while no patient showed erosive progression on MRI during 16 weeks of etanercept therapy; even though clinical and MRI signs of joint inflammation remained. This small study supports that erosive progression judged by MRI is minimal in RA patients treated with etanercept...

  15. Multidimensional diffusion MRI

    Topgaard, Daniel

    2017-02-01

    Principles from multidimensional NMR spectroscopy, and in particular solid-state NMR, have recently been transferred to the field of diffusion MRI, offering non-invasive characterization of heterogeneous anisotropic materials, such as the human brain, at an unprecedented level of detail. Here we revisit the basic physics of solid-state NMR and diffusion MRI to pinpoint the origin of the somewhat unexpected analogy between the two fields, and provide an overview of current diffusion MRI acquisition protocols and data analysis methods to quantify the composition of heterogeneous materials in terms of diffusion tensor distributions with size, shape, and orientation dimensions. While the most advanced methods allow estimation of the complete multidimensional distributions, simpler methods focus on various projections onto lower-dimensional spaces as well as determination of means and variances rather than actual distributions. Even the less advanced methods provide simple and intuitive scalar parameters that are directly related to microstructural features that can be observed in optical microscopy images, e.g. average cell eccentricity, variance of cell density, and orientational order - properties that are inextricably entangled in conventional diffusion MRI. Key to disentangling all these microstructural features is MRI signal acquisition combining isotropic and directional dimensions, just as in the field of multidimensional solid-state NMR from which most of the ideas for the new methods are derived.

  16. MRI of the lung

    Kauczor, Hans-Ulrich (ed.) [University Clinic Heidelberg (Germany). Diagnostic and Interventional Radiology

    2009-07-01

    For a long time, only chest X-ray and CT were used to image lung structure, while nuclear medicine was employed to assess lung function. During the past decade significant developments have been achieved in the field of magnetic resonance imaging (MRI), enabling MRI to enter the clinical arena of chest imaging. Standard protocols can now be implemented on up-to-date scanners, allowing MRI to be used as a first-line imaging modality for various lung diseases, including cystic fibrosis, pulmonary hypertension and even lung cancer. The diagnostic benefits stem from the ability of MRI to visualize changes in lung structure while simultaneously imaging different aspects of lung function, such as perfusion, respiratory motion, ventilation and gas exchange. On this basis, novel quantitative surrogates for lung function can be obtained. This book provides a comprehensive overview of how to use MRI for imaging of lung disease. Special emphasis is placed on benign diseases requiring regular monitoring, given that it is patients with these diseases who derive the greatest benefit from the avoidance of ionizing radiation. (orig.)

  17. Parametric T2 and T2* mapping techniques to visualize intervertebral disc degeneration in patients with low back pain: initial results on the clinical use of 3.0 Tesla MRI

    Welsch, Goetz Hannes [Medical University of Vienna, MR Center - High Field MR, Department of Radiology, Vienna (Austria); University of Erlangen, Department of Trauma Surgery, Erlangen (Germany); Trattnig, Siegfried; Goed, Sabine; Stelzeneder, David [Medical University of Vienna, MR Center - High Field MR, Department of Radiology, Vienna (Austria); Paternostro-Sluga, Tatjana [Medical University of Vienna, Department of Physical Therapy, Vienna (Austria); Bohndorf, Klaus [Klinikum Augsburg, Department of Radiology, Augsburg (Germany); Mamisch, Tallal Charles [Medical University of Vienna, MR Center - High Field MR, Department of Radiology, Vienna (Austria); University of Berne, Department of Orthopedic Surgery, Berne (Switzerland)

    2011-05-15

    To assess, compare and correlate quantitative T2 and T2* relaxation time measurements of intervertebral discs (IVDs) in patients suffering from low back pain, with respect to the IVD degeneration as assessed by the morphological Pfirrmann Score. Special focus was on the spatial variation of T2 and T2* between the annulus fibrosus (AF) and the nucleus pulposus (NP). Thirty patients (mean age: 38.1 {+-} 9.1 years; 20 female, 10 male) suffering from low back pain were included. Morphological (sagittal T1-FSE, sagittal and axial T2-FSE) and biochemical (sagittal T2- and T2* mapping) MRI was performed at 3 Tesla covering IVDs L1-L2 to L5-S1. All IVDs were morphologically classified using the Pfirrmann score. Region-of-interest (ROI) analysis was performed on midsagittal T2 and T2* maps at five ROIs from anterior to posterior to obtain information on spatial variation between the AF and the NP. Statistical analysis-of-variance and Pearson correlation was performed. The spatial variation as an increase in T2 and T2* values from the AF to the NP was highest at Pfirmann grade I and declined at higher Pfirmann grades II-IV (p < 0.05). With increased IVD degeneration, T2 and T2* revealed a clear differences in the NP, whereas T2* was additionally able to depict changes in the posterior AF. Correlation between T2 and T2* showed a medium Pearson's correlation (0.210 to 0.356 [p < 0.001]). The clear differentiation of IVD degeneration and the possible quantification by means of T2 and fast T2* mapping may provide a new tool for follow-up therapy protocols in patients with low back pain. (orig.)

  18. MRI of oriental cholangiohepatitis

    Wani, N.A., E-mail: ahmad77chinar@gmail.co [Department of Radiodiagnosis and Imaging, Sher-I-Kashmir Institute of Medical Sciences (SKIMS), Srinagar (India); Robbani, I.; Kosar, T. [Department of Radiodiagnosis and Imaging, Sher-I-Kashmir Institute of Medical Sciences (SKIMS), Srinagar (India)

    2011-02-15

    Oriental cholangiohepatitis (OCH) also called recurrent pyogenic cholangitis is characterized by intrahepatic duct calculi, strictures, and recurrent infections. In turn cholangitis can result in multiple hepatic abscesses, further biliary strictures, and in severe cases, progressive hepatic parenchymal destruction, cirrhosis, and portal hypertension. Magnetic resonance cholangiopancreatography (MRCP) and conventional T1-weighted (T1 W) and T2-weighted (T2 W) magnetic resonance imaging (MRI) findings have been described in patients with OCH. MRCP findings include duct dilation, strictures, and calculi. MRCP can help to localize the diseased ducts and determine the severity of involvement. T1 and T2 W sequences reveal the parenchymal changes of atrophy, abscess formation, and portal hypertension in addition to calculi. Post-treatment changes are also well depicted using MRI. Comprehensive, non-invasive assessment is achieved by using conventional MRI and MRCP in OCH providing a roadmap for endoscopic or surgical management.

  19. MRI findings of treated bacterial septic arthritis

    Bierry, Guillaume; Huang, Ambrose J.; Chang, Connie Y.; Torriani, Martin; Bredella, Miriam A. [Massachusetts General Hospital and Harvard Medical School, Musculoskeletal Imaging and Intervention, Department of Radiology, Boston, MA (United States)

    2012-12-15

    The purpose of this study was to report the MRI findings that can be encountered in successfully treated bacterial septic arthritis. The study included 12 patients (8 male and 4 female; mean age 38 years, range 9-85) with 13 proven cases of bacterial septic arthritis. The joints involved were hip (n = 3), knee (n = 3), shoulder (n = 2), sacroiliac (n = 2), ankle (n = 1), wrist (n = 1), and elbow (n = 1). MRI examinations following surgical debridement and at initiation of antibiotic therapy and after successful treatment were compared for changes in effusion, synovium, bone, and periarticular soft tissues. Imaging findings were correlated with microbiological and clinical findings. Joint effusions were present in all joints at baseline and regressed significantly at follow-up MRI (p = 0.001). Abscesses were present in 5 cases (38 %), and their sizes decreased significantly at follow-up (p = 0.001). Synovial enhancement and thickening were observed in all joints at both baseline and follow-up MRI. Myositis/cellulitis was present in 10 cases (77 %) at baseline and in 8 cases (62 %) at follow-up MRI. Bone marrow edema was present in 10 joints (77 %) at baseline and persisted in 8 joints (62 %). Bone erosions were found in 8 joints (62 %) and persisted at follow-up MRI in all cases. The sizes of joint effusions and abscesses appear to be the factors with the most potential for monitoring therapy for septic arthritis, since both decreased significantly following successful treatment. Synovial thickening and enhancement, periarticular myositis/cellulitis, and bone marrow edema can persist even after resolution of the infection. (orig.)

  20. Background and Mathematical Analysis of Diffusion MRI Methods.

    Ozcan, Alpay; Wong, Kenneth H; Larson-Prior, Linda; Cho, Zang-Hee; Mun, Seong K

    2012-03-01

    The addition of a pair of magnetic field gradient pulses had initially provided the measurement of spin motion with nuclear magnetic resonance (NMR) techniques. In the adaptation of DW-NMR techniques to magnetic resonance imaging (MRI), the taxonomy of mathematical models is divided in two categories: model matching and spectral methods. In this review, the methods are summarized starting from early diffusion weighted (DW) NMR models followed up with their adaptation to DW MRI. Finally, a newly introduced Fourier analysis based unifying theory, so-called Complete Fourier Direct MRI, is included to explain the mechanisms of existing methods.

  1. Introduction to Interventional MRI

    Jarmo Ruohonen; William G.Bradley; Jr.MD

    2002-01-01

    An increasing number of interventional procedures are done under imaging guidance. These include biopsies, drainages and injections. Likewise, imaging guidance and monitoring have enabled the use of sophisticated techniques for minimally invasive therapy of tumors. Since MRI provides the best tissue contrast and lesion sensitivity,the use of MR-guided procedures (MRGP) is quickly gaining momentum. Special hardware and software solutions have been developed that allow more efficient interventional use of the MR scanner.This introduction summarizes the basic concepts of interventional MRI and outlines some of the applications of today and tomorrow.

  2. MRI of osteonecrosis

    Saini, A. [Department of Radiology, Royal National Orthopaedic Hospital NHS Trust, Stanmore, Middlesex (United Kingdom); Saifuddin, A. [Department of Radiology, Royal National Orthopaedic Hospital NHS Trust, Stanmore, Middlesex (United Kingdom)]. E-mail: asaifuddin@aol.com

    2004-12-01

    Osteonecrosis is a relatively common condition, which may be idiopathic or secondary to a variety of clinical situations. It may involve the subarticular region of a joint, when it is commonly referred to as ischaemic necrosis, or the metaphyseal regions of long bones, when it is referred to as bone infarction. In both situations, early lesions may be radiographically occult. However, magnetic resonance imaging (MRI) is very sensitive in identifying and characterizing osteonecrosis. This review illustrates the varied MRI features of osteonecrosis that enable a confident diagnosis to be made. Complications and differential diagnosis are also considered.

  3. Optimised, low cost, low field dedicated extremity MRI is highly specific and sensitive for synovitis and bone erosions in rheumatoid arthritis wrist and finger joints: comparison with conventional high field MRI and radiography

    Ejbjerg, B.J; Narvestad, E; Jacobsen, S;

    2005-01-01

    of the wrist and 2nd-5th MCP joints was performed on a low field MRI unit (0.2 T Esaote Artoscan) and a high field MRI unit (1.0 T Siemens Impact) on 2 subsequent days. MRI was performed and evaluated according to OMERACT recommendations. Additionally, conventional x ray, clinical, and biochemical examinations......OBJECTIVE: To evaluate a low field dedicated extremity MRI unit for detection of bone erosions, synovitis, and bone marrow oedema in wrist and metacarpophalangeal (MCP) joints, with a high field MRI unit as the standard reference. METHODS: In 37 patients with RA and 28 healthy controls MRI...... were performed. In an initial low field MRI 'sequence selection phase', based on a subset of 10 patients and 10 controls, sequences for comparison with high field MRI were selected. RESULTS: With high field, spin echo MRI considered as the reference method, the sensitivity, specificity, and accuracy...

  4. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... MRI scanners are air-conditioned and well-lit. Music may be played through the headphones to help ... Brain Tumor Treatment Magnetic Resonance Imaging (MRI) Safety Alzheimer's Disease Head Injury Brain Tumors Images related to ...

  5. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... is done because a potential abnormality needs further evaluation with additional views or a special imaging technique. ... MRI an invaluable tool in early diagnosis and evaluation of many conditions, including tumors. MRI enables the ...

  6. Quality assurance in functional MRI

    Liu, Thomas T; Glover, Gary H; Mueller, Bryon A

    2015-01-01

    Over the past 20 years, functional magnetic resonance imaging (fMRI) has ben- efited greatly from improvements in MRI hardware and software. At the same time, fMRI researchers have pushed the technical limits of MRI systems and greatly in- fluenced the development of state-of-the-art systems....... Minimizing image noise and maximizing system stability is critical in fMRI because the blood oxygenation level- dependent (BOLD) signal changes that are used for most fMRI studies represent only a small fraction of the total MR signal. In addition, multiple imaging volumes must be acquired over time to track...... cognitive processes. As a result, MRI scanners must have excellent time-series stability to accurately measure BOLD signal changes over the course of a long time series (typically on the order of 10 min per scan). fMRI studies are particularly demanding on the scanner hardware because they utilize fast...

  7. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... have this exam in the first trimester of pregnancy unless the potential benefit from the MRI exam ... See the Safety page for more information about pregnancy and MRI. If you have claustrophobia (fear of ...

  8. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... medically necessary. MRI may not always distinguish between cancer tissue and fluid, known as edema . MRI typically ... Brain Tumors Radiation Therapy for Head and Neck Cancer Others : American Stroke Association National Stroke Association top ...

  9. Magnetic Resonance Imaging (MRI) -- Head

    ... 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 ...

  10. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... 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 ...

  11. Getting an MRI (For Kids)

    Full Text Available ... dientes Video: Getting an X-ray Getting an MRI (Video) KidsHealth > For Kids > Getting an MRI (Video) Print A A A en español Obtención de una resonancia magnética, RM (video) An MRI (magnetic resonance imaging) scan creates detailed pictures of ...

  12. Getting an MRI (For Kids)

    ... dientes Video: Getting an X-ray Getting an MRI (Video) KidsHealth > For Kids > Getting an MRI (Video) Print A A A en español Obtención de una resonancia magnética, RM (video) An MRI (magnetic resonance imaging) scan creates detailed pictures of ...

  13. Less Confusion in Diffusion MRI

    Tax, C.M.W.

    2016-01-01

    With its unique ability to investigate tissue architecture and microstructure in vivo, diffusion MRI (dMRI) has gained tremendous interest and the society has been continuously triggered to develop novel dMRI image analysis approaches. With the overwhelming amount of strategies currently available i

  14. Vesicouterine fistula: MRI diagnosis

    Murphy, J.M.; Lomas, D.J. [Dept. of Radiology, Addenbrooke' s Hospital and University of Cambridge, Cambridge (United Kingdom); Lee, G.; Doble, A. [Dept. of Urology, Addenbrooke' s Hospital and University of Cambridge (United Kingdom); Sharma, S.D. [Dept. of Urology, Peterborough NHS Trust Hospital (United Kingdom)

    1999-07-01

    A case of vesicouterine fistula in a young woman following caesarean section is presented. The diagnosis was established successfully using heavily T2-weighted MRI which clearly demonstrated fluid within the fistula, obviating the need for conventional radiographic contrast examination. (orig.)

  15. MRI in suspected appendicitis

    Leeuwenburgh, M.M.N.

    2014-01-01

    Dit proefschrift richt zich op de optimalisatie van beeldvormende diagnostiek bij patiënten met een klinische verdenking op appendicitis, waarbij het gebruik van ‘magnetic resonance imaging’ (MRI) wordt verkend. Het proefschrift omvat de resultaten van de OPTIMAP-studie (OPTimisation of IMaging Appe

  16. Sinus MRI scan

    ... A CT scan may be preferred in emergency cases, since it is faster and often available in the emergency room. Note: MRI is not as effective as CT in defining the anatomy of the sinuses, and therefore is not typically used for suspected acute sinusitis.

  17. MRI of intact plants.

    As, H. van; Scheenen, T.W.J.; Vergeldt, F.J.

    2009-01-01

    Nuclear magnetic resonance imaging (MRI) is a non-destructive and non-invasive technique that can be used to acquire two- or even three-dimensional images of intact plants. The information within the images can be manipulated and used to study the dynamics of plant water relations and water transpor

  18. MRI of intact plants

    As, van H.; Scheenen, T.; Vergeldt, F.J.

    2009-01-01

    Nuclear magnetic resonance imaging (MRI) is a non-destructive and non-invasive technique that can be used to acquire two- or even three-dimensional images of intact plants. The information within the images can be manipulated and used to study the dynamics of plant water relations and water transpor

  19. MRI of the Chest

    Full Text Available ... MRI. If you have a history of kidney disease or liver transplant, it will be necessary to perform a blood test to determine whether the kidneys are functioning adequately. Women should always inform their physician or technologist if ...

  20. MRI of the Chest

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician ... Magnetic resonance imaging (MRI) is a noninvasive medical test that physicians use to diagnose and treat medical ...

  1. In vitro MRI of brain development

    Rados, Marko [Croatian Institute for Brain Research, School of Medicine, University of Zagreb, Salata 12, 10000 Zagreb (Croatia); Clinical Hospital Center Zagreb, School of Medicine, University of Zagreb, Kispaticeva 12, 10000 Zagreb (Croatia); Judas, Milos [Croatian Institute for Brain Research, School of Medicine, University of Zagreb, Salata 12, 10000 Zagreb (Croatia); Kostovic, Ivica [Croatian Institute for Brain Research, School of Medicine, University of Zagreb, Salata 12, 10000 Zagreb (Croatia)]. E-mail: ikostov@hiim.h

    2006-02-15

    In this review, we demonstrate the developmental appearance, structural features, and reorganization of transient cerebral zones and structures in the human fetal brain using a correlative histological and MRI analysis. The analysis of postmortem aldehyde-fixed specimens (age range: 10 postovulatory weeks to term) revealed that, at 10 postovulatory weeks, the cerebral wall already has a trilaminar appearance and consists of: (1) a ventricular zone of high cell-packing density; (2) an intermediate zone; (3) the cortical plate (in a stage of primary consolidation) with high MRI signal intensity. The anlage of the hippocampus is present as a prominent bulging in the thin limbic telencephalon. The early fetal telencephalon impar also contains the first commissural fibers and fornix bundles in the septal area. The ganglionic eminence is clearly visible as an expanded continuation of the proliferative ventricular zone. The basal ganglia showed an initial aggregation of cells. The most massive fiber system is in the hemispheric stalk, which is in continuity with thalamocortical fibers. During the mid-fetal period (15-22 postovulatory weeks), the typical fetal lamination pattern develops and the cerebral wall consists of the following zones: (a) a marginal zone (visible on MRI exclusively in the hippocampus); (b) the cortical plate with high cell-packing density and high MRI signal intensity; (c) the subplate zone, which is the most prominent zone rich in extracellular matrix and with a very low MRI signal intensity; (d) the intermediate zone (fetal 'white matter'); (e) the subventricular zone; (f) the periventricular fiber-rich zone; (g) the ventricular zone. The ganglionic eminence is still a very prominent structure with an intense proliferative activity. During the next period (22-26 postovulatory weeks), there is the developmental peak of transient MRI features, caused by the high content of hydrophyllic extracellular matrix in the subplate zone and the

  2. MRI of 'brain death'

    Nishino, Shigeki; Itoh, Takahiko; Tuchida, Shohei; Kinugasa, Kazushi; Asari, Shoji; Nishimoto, Akira (Okayama Univ. (Japan). School of Medicine); Sanou, Kazuo

    1990-12-01

    Magnetic resonance imaging (MRI) was undertaken for two patients who suffered from severe cerebrovascular diseases and were clinically brain dead. The MRI system we used was Resona (Yokogawa Medical Systems, superconductive system 0.5 T) and the CT apparatus was Toshiba TCT-300. Initial CT and MRI were undertaken as soon as possible after admission, and repeated sequentially. After diagnosis of brain death, we performed angiography to determine cerebral circulatory arrest, and MRI obtained at the same time was compared with the angiogram and CT. Case 1 was a 77-year-old man who was admitted in an unconscious state. CT and MRI on the second day after hospitalization revealed cerebellar infarction. He was diagnosed as brain dead on day 4. Case 2 was a 35-year-old man. When he was transferred to our hospital, he was in cardiorespiratory arrested. Cardiac resuscitation was successful but no spontaneous respiration appeared. CT and MRI on admission revealed right intracerebral hemorrhage. Angiography revealed cessation of contrast medium in intracranial vessels in both of the patients. We found no 'flow signal void sign' in the bilateral internal carotid and basilar arteries on MRI images in both cases after brain death. MRI, showing us the anatomical changes of the brain, clearly revealed brain herniations, even though only nuclear findings of 'brain tamponade' were seen on CT. But in Case 1, we could not see the infarct lesions in the cerebellum on MR images obtained after brain death. This phenomenon was caused by the whole brain ischemia masking the initial ischemic lesions. We concluded that MRI was useful not only the anatomical display of lesions and brain herniation with high contrast resolution but for obtaining information on cerebral circulation of brain death. (author).

  3. MRI of the cardiomyopathies

    Di Cesare, Ernesto E-mail: ernesto.dicesare@cc.univaq.it

    2001-06-01

    We examined the potentialities of Magnetic resonance imaging (MRI) in the evaluation of the main cardiomyopathies: hypertrophic, dilated, restrictive and arrhythmogenic right ventricular. The hypertrophic cardiomyopathy is generally adequately investigated by echocardiography, that well defines the myocardial thickening and the obstruction of the left ventricular output. However, by echocardiography we still have difficulties in the evaluation of the apex of the left ventricle and the right ventricle involvement. MRI provides a complete evaluation of the heart with a clear evidence also of the echocardiographic dark zones by means of a clear evidence of the apex of the right ventricle. The dilated form is also well investigated by MRI that provides a clear evaluation of the volumes, mass and ejection fraction by means of the 3D analysis including conditions of the ventricular remodelling. Moreover, this technique helps in the differential diagnosis of acute myocarditis. In the acute phase of myocarditis (first 2 weeks), in fact, the myocardium produces high signal intensity on the T2 weighted sequences due to the presence of oedema. The third form of cardiomyopathy is the restrictive one, characterised by reduced diastolic filling and diastolic volume, normality of the systolic function and parietal thickness, interstitial fibrosis and enlargement of both atria. The mean potentiality of MRI is related to the differential diagnosis with constrictive pericarditis. Only in the former, the pericardium appears irregularly thickened with areas exceeding 4 mm of pericardial thickness. Finally, the right ventricular arrhythmogenic cardiomyopathy represents the main indication to MRI evaluation. With this imaging modality we are can obtain a clear morpho-functional evaluation of the right ventricle and distinguish the intramyocardial adipose substitution characterised by areas of high signal in the myocardium.

  4. MRI Findings in Patients with TMJ Click

    Mahrokh Imanimoghaddam

    2013-12-01

    Full Text Available Introduction: It has been shown that joint click, an initial and common finding in internal derangement (ID, respond to neither conservative treatment nor surgical intervention. This raises the question as to whether it must be treated in the absence of other pertinent signs and symptoms, so the aim of this study was to investigate and compare the MRI findings of TMJ in both normal subjects and patients with click, in order to determine the importance of click in predicting TMJ pathological changes. Methods: A total of 26 patients with clinical symptoms of disk displacement with reduction (DDwR according to RDC/TMD were compared to 14 normal subjects in terms of their MRI findings, including disk displacement, effusion, condylar osteoarthritic changes and disk deformities. Results: Out of 80 joints in total (52 affected joints in 26 patients and 28 joints in control group, 48 were shown with normal disk position in MRI whereas 28 (35% and 4 (5% were categorised as DDwR and (disk displacement without reduction DDwoR, respectively. Statistically significant correlations were established between the following pairs of variables in order: Click and disk displacement, effusion and disk displacement, disk displacement and effusion with disk deformity. Conclusion: The correlation between the presence of click and disk displacement, disk deformity and effusion emphasizes the importance of MRI for an accurate diagnosis and development of an appropriate treatment plan in these cases and shows that clinical examination is not sufficient for these purposes.

  5. Postinterventional MRI findings following MRI-guided laser ablation of osteoid osteoma

    Fuchs, S., E-mail: simon.fuchs@charite.de [Department of Radiology, Charité, Humboldt University, Berlin (Germany); Gebauer, B.; Stelter, L.; Schäfer, M.L.; Renz, D.M. [Department of Radiology, Charité, Humboldt University, Berlin (Germany); Melcher, I.; Schaser, K. [Center for Musculoskeletal Surgery, Charité, Humboldt University, Berlin (Germany); Hamm, B.; Streitparth, F. [Department of Radiology, Charité, Humboldt University, Berlin (Germany)

    2014-04-15

    Objective: To evaluate postinterventional magnetic resonance imaging (MRI) characteristics following MRI-guided laser ablation of osteoid osteoma (OO). Materials and methods: 35 patients treated with MRI-guided laser ablation underwent follow-up MRI immediately after the procedure, after 3, 6, 12, 24, 36, and up to 48 months. The imaging protocol included multiplanar fat-saturated T2w TSE, unenhanced and contrast-enhanced T1w SE, and subtraction images. MR images were reviewed regarding the appearance and size of treated areas, and presence of periablation bone and soft tissue changes. Imaging was correlated with clinical status. Results: Mean follow-up time was 13.6 months. 28/35 patients (80%) showed a postinterventional “target-sign” appearance consisting of a fibrovascular rim zone and a necrotic core area. After an initial increase in total lesion diameter after 3 months, a subsequent progressive inward remodeling process of the zonal compartments was observed for up to 24 months. Periablation bone and soft tissue changes showed a constant decrease over time. MR findings correlated well with the clinical status. Clinical success was achieved in 32/35 (91%). Conclusions: Evaluation of long-term follow-up MRI after laser ablation of OO identified typical postinterventional changes and thus may contribute to the interpretation of therapeutic success and residual or recurrent OO in suspected cases.

  6. The MRI appearances of early vertebral osteomyelitis and discitis

    Dunbar, J.A.T.; Sandoe, J.A.T. [Department of Microbiology, Leeds General Infirmary, Leeds LS1 3EX (United Kingdom); Rao, A.S. [Department of Orthopaedics, Leeds General Infirmary, Leeds LS1 3EX (United Kingdom); Crimmins, D.W. [Department of Neurosurgery, Leeds General Infirmary, Leeds LS1 3EX (United Kingdom); Baig, W. [Department of Cardiology, Leeds General Infirmary, Leeds LS1 3EX (United Kingdom); Rankine, J.J., E-mail: james.rankine@leedsth.nhs.u [Department of Radiology, Leeds General Infirmary, Leeds LS1 3EX (United Kingdom); Leeds Musculoskeletal Biomedical Research Unit, Leeds (United Kingdom)

    2010-12-15

    Aim: To describe the magnetic resonance imaging (MRI) appearances in patients with a clinical history suggestive of vertebral osteomyelitis and discitis who underwent MRI very early in their clinical course. Materials and methods: A retrospective review of the database of spinal infections from a spinal microbiological liaison team was performed over a 2 year period to identify cases with clinical features suggestive of spinal infection and an MRI that did not show features typical of vertebral osteomyelitis and discitis. All patients had positive microbiology and a follow up MRI showing typical features of spinal infection. Results: In four cases the features typical of spinal infection were not evident at the initial MRI. In three cases there was very subtle endplate oedema associated with disc degeneration, which was interpreted as Modic type I degenerative endplate change. Intravenous antibiotic therapy was continued prior to repeat MRI examinations. The mean time to the repeat examination was 17 days with a range of 8-22 days. The second examinations clearly demonstrated vertebral osteomyelitis and discitis. Conclusion: Although MRI is the imaging method of choice for vertebral osteomyelitis and discitis in the early stages, it may show subtle, non-specific endplate subchondral changes; a repeat examination may be required to show the typical features.

  7. MRI of cardiovascular malformations

    Kastler, Bruno [Centre Hospitalier Univ. Jean Minjoz, Besancon (France); Universite de Franche-Comte, Besancon (FR). Lab. I4S (Health, Innovation, Intervention, Imaging, Engineering); Centre Hospitalier Sherbrooke Univ., PQ (Canada). Dept. of Radiology

    2011-07-01

    MRI is a non-invasive and non-ionizing imaging modality that is perfectly suited for the diagnosis and follow-up of both pediatric and adult congenital heart disease. It provides a large field of view and has the unique ability to depict complex cardiac and vascular anatomy and to measure cardiac function and flow within one examination. MRI is the ideal complement to echocardiography whenever the information provided by the latter is limited. This book has been conceived as a self-teaching manual that will assist qualified radiologists, cardiologists, and pediatricians, as well as those in training. It is richly illustrated with numerous images and drawings that cover all usual and most unusual anomalies. The principal author, Professor Bruno Kastler, is head of radiology at Besancon University Hospital, France and is board certified in both radiology and cardiology. (orig.)

  8. MRI of the shoulder

    Vahlensieck, M.

    2000-02-01

    Shoulder imaging is one of the major applications in musculoskeletal MRI. In order to analyze the images it is important to keep informed about anatomical and pathological findings and publications. In this article MRI technique, anatomy and pathology is reviewed. Technical considerations about MR sequences and examination strategy are only shortly discussed with emphasis on turbo spin echo and short T1 inversion recovery imaging. Basic anatomy as well as recent findings, including macroscopic aspects of the supraspinatus fat pad, composition of the supraspinatus muscle belly, and variability of the glenohumeral ligaments or coracoid ligament, are presented. Basic pathological conditions are described in detail, e. g. instability particularly problems in differentiating the various subtypes of labral pathology. Rotator cuff diseases are elucidated with emphasis on some rarer entities such as subscapularis calcifying tendinitis, coracoid impingement, chronic bursitis producing the double-line sign, prominent coraco-acromial ligament and the impingement due to an inflamed os acromiale. (orig.)

  9. MRI (Magnetic Resonance Imager)

    Suzuki, Yoshinori [Toshiba Corp., Kawasaki, Kanagawa (Japan)

    1995-05-01

    MRI is a widely used diagnostic imaging modality because it has excellent diagnostic capabilities, is safe to use and generates images not affected by bone artifacts. Images are obtained by utilizing the phenomenon of Nuclear Magnetic Resonance (NMR) by which protons located in a static magnetic field absorb radio frequency (RF) pulses with a specific frequency and release a part of the energy as a NMR signal. Potentially MRI has the ability to provide functional and metabolic information (such as flow, temperature, diffusion, neuron activity) in addition to morphological information. This paper describes the imaging principles and provides a general outline of some applications: flow imaging, metabolite imaging and temperature imaging. (J.P.N.).

  10. Three-Dimensional Expansion of a Dynamic Programming Method for Boundary Detection and Its Application to Sequential Magnetic Resonance Imaging (MRI

    Da-Chuan Cheng

    2012-04-01

    Full Text Available This study proposes a fast 3D dynamic programming expansion to find a shortest surface in a 3D matrix. This algorithm can detect boundaries in an image sequence. Using phantom image studies with added uniform distributed noise from different SNRs, the unsigned error of this proposed method is investigated. Comparing the automated results to the gold standard, the best averaged relative unsigned error of the proposed method is 0.77% (SNR = 20 dB, and its corresponding parameter values are reported. We further apply this method to detect the boundary of the real superficial femoral artery (SFA in MRI sequences without a contrast injection. The manual tracings on the SFA boundaries are performed by well-trained experts to be the gold standard. The comparisons between the manual tracings and automated results are made on 16 MRI sequences (800 total images. The average unsigned error rate is 2.4% (SD = 2.0%. The results demonstrate that the proposed method can perform qualitatively better than the 2D dynamic programming for vessel boundary detection on MRI sequences.

  11. {sup 3}He-MRI in follow-up of lung transplant recipients

    Gast, Klaus Kurt; Zaporozhan, Julia; Ley, Sebastian; Biedermann, Alexander; Knitz, Frank; Eberle, Balthasar; Schmiedeskamp, Joerg; Heussel, Claus-Peter; Mayer, Eckhard; Schreiber, Wolfgang Guenter; Thelen, Manfred; Kauczor, Hans-Ulrich [Department of Radiology, Johannes Gutenberg University Hospital, Langenbeckstrasse 1, 55131, Mainz (Germany)

    2004-01-01

    The aim of this study was to evaluate the possible contribution of {sup 3}He-MRI to detect obliterative bronchiolitis (OB) in the follow-up of lung transplant recipients. Nine single- and double-lung transplanted patients were studied by an initial and a follow-up {sup 3}He-MRI study. Images were evaluated subjectively by estimation of ventilation defect area and quantitatively by individually adapted threshold segmentation and subsequent calculation of ventilated lung volume. Bronchiolitis obliterans syndrome (BOS) was diagnosed using pulmonary function tests. At {sup 3}He-MRI, OB was suspected if ventilated lung volume had decreased by 10% or more at the follow-up MRI study compared with the initial study. General accordance between pulmonary function testing and {sup 3}He-MRI was good, although subjective evaluation of {sup 3}He-MRI underestimated improvement in ventilation as obtained by pulmonary function tests. The {sup 3}He-MRI indicated OB in 6 cases. According to pulmonary function tests, BOS was diagnosed in 5 cases. All diagnoses of BOS were also detected by {sup 3}He-MRI. In 2 of these 5 cases, {sup 3}He-MRI indicated OB earlier than pulmonary function tests. The results support the hypothesis that {sup 3}He-MRI may be sensitive for early detection of OB and emphasize the need for larger prospective follow-up studies. (orig.)

  12. X-Ray and MRI Correlation of Bone Tumours

    Mitesh D. Ghadiali

    2015-12-01

    Full Text Available Introduction: The evaluation of all skeletal lesions should begin with plain radiographic imaging. These images give basic information about its site, its location,its morphology, its aggressiveness. After the initial plain radiographic evaluation, the next imaging modality of choice is MRI. its clinical applications in the form of diagnostic and therapeutic monitoring has reached a new height in musculoskeletal imaging1. Method: Correlating x-ray findings with mri findings to know the sensitivity and specificity of each diagnostic modality and to know role of each in planning management 30 patients were studied,The plain film included at least 2 projection depending on location and then patients underwent MRI. Result: MRI is useful for information regarding soft tissue component, periosteal reaction where as XRAY is useful for information regarding bone and tumour calcification [Natl J Med Res 2015; 5(4.000: 309-311

  13. Edge-oriented dual-dictionary guided enrichment (EDGE) for MRI-CT image reconstruction.

    Li, Liang; Wang, Bigong; Wang, Ge

    2016-01-01

    In this paper, we formulate the joint/simultaneous X-ray CT and MRI image reconstruction. In particular, a novel algorithm is proposed for MRI image reconstruction from highly under-sampled MRI data and CT images. It consists of two steps. First, a training dataset is generated from a series of well-registered MRI and CT images on the same patients. Then, an initial MRI image of a patient can be reconstructed via edge-oriented dual-dictionary guided enrichment (EDGE) based on the training dataset and a CT image of the patient. Second, an MRI image is reconstructed using the dictionary learning (DL) algorithm from highly under-sampled k-space data and the initial MRI image. Our algorithm can establish a one-to-one correspondence between the two imaging modalities, and obtain a good initial MRI estimation. Both noise-free and noisy simulation studies were performed to evaluate and validate the proposed algorithm. The results with different under-sampling factors show that the proposed algorithm performed significantly better than those reconstructed using the DL algorithm from MRI data alone.

  14. MRI assessment of cervical cancer for adaptive radiotherapy

    Dimopoulos, Johannes C.A.; Schirl, Gertrude; Baldinger, Anja; Poetter, Richard [Medical Univ. of Vienna (Austria). Dept. of Radiotherapy; Helbich, Thomas H. [Medical Univ. of Vienna (Austria). Dept of Radiology

    2009-05-15

    Purpose: To assess the importance of the information obtained from MRI for adaptive cervix cancer radiotherapy. Patients and methods: 49 patients with cervix cancer, treated by external-beam radiotherapy (EBRT) and MRI-assisted high-dose-rate brachytherapy {+-} concomitant cisplatin, underwent MRI at diagnosis and at the time of brachytherapy fractions. 190 MRI examinations were performed. Pretreatment scans were correlated with clinical examination (CE) findings. Measurements in 3-D of the tumor extension and also of the distance from the tumor to the pelvic side wall were performed using both MRI and CE. The tumor volume regression induced initially by EBRT and the subsequent regression after each brachytherapy fraction were assessed. Results: MRI and CE showed 92% agreement in overall parametrial staging and 73% agreement in terms of vaginal involvement. There was, however, disagreement in parametrial side (right/left) classification in 25% of the parametria examined. These were patients with unilateral displacement of the cervix and contralateral invasion of the parametrium. The mean tumor volume on the pretreatment MRI scan (GTVD) was 61 cm{sup 3}. At the time of the four brachytherapy fractions the mean was 16 cm{sup 3}, 10 cm{sup 3}, 9 cm{sup 3}, and 8 cm{sup 3}, defined as the GTVBT plus the gray zones in the parametria. Conclusion: CE and MRI findings agree well in terms of overall staging. The clinical assessment of side-specific parametrial invasion improved when having access to the additional knowledge obtained from MRI. The greatest decrease in tumor volume occurs during EBRT, whereas tumor regression between the first and subsequent brachytherapy fractions is minor. (orig.)

  15. Pediatric elbow fractures: MRI evaluation

    Beltran, J. (Dept. of Radiology, Hospital for Joint Diseases, New York, NY (United States)); Rosenberg, Z.S. (Dept. of Radiology, Hospital for Joint Diseases, New York, NY (United States)); Kawelblum, M. (Dept. of Orthopaedic Surgery, Hospital for Joint Diseases, New York, NY (United States)); Montes, L. (Dept. of Radiology, Beth Israel Medical Center, New York, NY (United States)); Bergman, A.G. (Dept. of Radiology, Stanford Univ., School of Medicine, CA (United States)); Strongwater, A. (Dept. of Orthopaedic Surgery, Hospital for Joint Diseases, New York, NY (United States))

    1994-05-01

    Magnetic resonance imaging (MRI) was performed in eight patients under the age of 8 years who suffered elbow fractures, to assess possible fracture extension into the distal nonossified epiphysis of the humerus in seven cases and to determine the displacement and location of the radial head in one case. MRI allowed accurate depiction of the fracture line when it extended into the cartilaginous epiphysis. In four cases, MRI findings were confirmed at surgery. In five cases, surgery was obviated because no articular extension of the fracture was seen on MRI (4 cases) or because no displacement was noted (1 case). In one patient, the plain film diagnosis of a Salter type II fracture was changed to Salter type IV on the basis of the MRI findings. It is concluded that MRI might play a role in the preoperative evaluation of pediatric patients presenting with elbow trauma when extension of the fracture cannot be determined with routine radiographic studies. (orig.)

  16. MRI follow-up of conservatively treated meniscal knee lesions in general practice

    Oei, Edwin H.G.; Hunink, M.G.M. [University Medical Center Rotterdam, Program for the Assessment of Radiological Technology (ART Program), Erasmus MC, Rotterdam (Netherlands); University Medical Center Rotterdam, Department of Radiology, Erasmus MC, Rotterdam (Netherlands); University Medical Center Rotterdam, Department of Epidemiology, Erasmus MC, Rotterdam (Netherlands); Koster, Ingrid M. [University Medical Center Rotterdam, Department of Radiology, Erasmus MC, Rotterdam (Netherlands); Maasstad Ziekenhuis, Department of Radiology, Rotterdam (Netherlands); Hensen, Jan-Hein J.; Vroegindeweij, Dammis [Maasstad Ziekenhuis, Department of Radiology, Rotterdam (Netherlands); Boks, Simone S. [University Medical Center Rotterdam, Department of General Practice, Erasmus MC, Rotterdam (Netherlands); Maasstad Ziekenhuis, Department of Radiology, Rotterdam (Netherlands); Diaconessenhuis Meppel, Department of Radiology, Meppel (Netherlands); Wagemakers, Harry P.A.; Koes, Bart W.; Bierma-Zeinstra, Sita M.A. [University Medical Center Rotterdam, Department of General Practice, Erasmus MC, Rotterdam (Netherlands)

    2010-05-15

    To evaluate meniscal status change on follow-up MRI after 1 year, prognostic factors and association with clinical outcome in patients with conservatively treated knee injury. We analysed 403 meniscal horns in 101 conservatively treated patients (59 male; mean age 40 years) in general practice who underwent initial knee MRI within 5 weeks of trauma. We performed ordinal logistic regression analysis to analyse prognostic factors for meniscal change on follow-up MRI after 1 year, and we assessed the association with clinical outcome. On follow-up MRI 49 meniscal horns had deteriorated and 18 had improved. Age (odds ratio [OR] 1.3/decade), body weight (OR 1.2/10 kg), total anterior cruciate ligament (ACL) rupture on initial MRI (OR 2.4), location in the posterior horn of the medial meniscus (OR 3.0) and an initial meniscal lesion (OR 0.3) were statistically significant predictors of meniscal MRI appearance change after 1 year, which was not associated with clinical outcome. In conservatively treated patients, meniscal deterioration on follow-up MRI 1 year after trauma is predicted by higher age and body weight, initial total ACL rupture, and location in the medial posterior horn. Change in MRI appearance is not associated with clinical outcome. (orig.)

  17. US correlation for MRI-detected breast lesions in women with familial risk of breast cancer.

    Sim, L.S.; Hendriks, J.H.C.L.; Bult, P.; Fook-Chong, S.M.

    2005-01-01

    AIM: To examine the value of US correlation for MRI-detected breast lesions in women with familial risk of breast cancer. METHODS: From an initial dataset of 245 women with positive family history who had breast cancer surveillance involving mammography or MRI between November 1994 and February 2001

  18. MRI quantification of rheumatoid arthritis: Current knowledge and future perspectives

    Boesen, Mikael [Parker Institute, Frederiksberg University Hospital, Copenhagen (Denmark)], E-mail: parker@frh.regionh.dk; Ostergaard, Mikkel [Department of Rheumatology, Hvidovre and Herlev University Hospitals, Copenhagen (Denmark); Cimmino, Marco A. [Department of Rheumatology, University of Genoa, Genoa (Italy); Kubassova, Olga [Image Analysis LTD, Leeds (United Kingdom); Jensen, Karl Erik [Department of Radiology, MR section, Rigshospitalet, Copenhagen (Denmark); Bliddal, Henning [Parker Institute, Frederiksberg University Hospital, Copenhagen (Denmark)

    2009-08-15

    The international consensus on treatment of rheumatoid arthritis (RA) involves early initiation of disease modifying anti-rheumatic drugs (DMARDs) for which a reliable identification of early disease is mandatory. Conventional radiography of the joints is considered the standard method for detecting and quantifying joint damage in RA. However, radiographs only show late disease manifestations as joint space narrowing and bone erosions, whereas it cannot detect synovitis and bone marrow oedema, i.e., inflammation in the synovium or the bone, which may be visualized by magnetic resonance imaging (MRI) months to years before erosions develop. Furthermore, MRI allows earlier visualization of bone erosions than radiography. In order to allow early treatment initiation and optimal guidance of the therapeutic strategy, there is a need for methods which are capable of early detection of inflammatory joint changes. In this review, we will discuss available data, advantages, limitations and potential future of MRI in RA.

  19. Ovarian cysts on prenatal MRI

    Nemec, Ursula [Department of Radiology, Division of Neuroradiology and Musculoskeletal Radiology, Medical University Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria); Nemec, Stefan F., E-mail: stefan.nemec@meduniwien.ac.at [Department of Radiology, Division of Neuroradiology and Musculoskeletal Radiology, Medical University Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria); Medical Genetics Institute, Cedars Sinai Medical Center, 8700 Beverly Boulevard, PACT Suite 400, Los Angeles, CA 90048 (United States); Bettelheim, Dieter [Department of Obstetrics and Gynaecology, Division of Prenatal Diagnosis and Therapy, Medical University Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria); Brugger, Peter C. [Center of Anatomy and Cell Biology, Integrative Morphology Group, Medical University Vienna, Waehringerstrasse 13, A-1090 Vienna (Austria); Horcher, Ernst [Department of Pediatric Surgery, Medical University Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria); Schoepf, Veronika [Department of Radiology, Division of Neuroradiology and Musculoskeletal Radiology, Medical University Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria); Graham, John M.; Rimoin, David L. [Medical Genetics Institute, Cedars Sinai Medical Center, 8700 Beverly Boulevard, PACT Suite 400, Los Angeles, CA 90048 (United States); Weber, Michael; Prayer, Daniela [Department of Radiology, Division of Neuroradiology and Musculoskeletal Radiology, Medical University Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria)

    2012-08-15

    Objective: Ovarian cysts are the most frequently encountered intra-abdominal masses in females in utero. They may, at times, require perinatal intervention. Using magnetic resonance imaging (MRI) as an adjunct to ultrasonography (US) in prenatal diagnosis, we sought to demonstrate the ability to visualize ovarian cysts on prenatal MRI. Materials and methods: This retrospective study included 17 fetal MRI scans from 16 female fetuses (23-37 gestational weeks) with an MRI diagnosis of ovarian cysts after suspicious US findings. A multiplanar MRI protocol was applied to image and to characterize the cysts. The US and MRI findings were compared, and the prenatal findings were compared with postnatal imaging findings or histopathology. Results: Simple ovarian cysts were found in 10/16 cases and complex cysts in 7/16 cases, including one case with both. In 11/16 (69%) cases, US and MRI diagnoses were in agreement, and, in 5/16 (31%) cases, MRI specified or expanded the US diagnosis. In 6/16 cases, postnatal US showed that the cysts spontaneously resolved or decreased in size, and in 1/16 cases, postnatal imaging confirmed a hemorrhagic cyst. In 4/16 cases, the prenatal diagnoses were confirmed by surgery/histopathology, and for the rest, postnatal correlation was not available. Conclusion: Our results illustrate the MRI visualization of ovarian cysts in utero. In most cases, MRI will confirm the US diagnosis. In certain cases, MRI may provide further diagnostic information, additional to US, which is the standard technique for diagnosis, monitoring, and treatment planning.

  20. MRI of the cartilage

    Imhof, H.; Noebauer-Huhmann, I.-M.; Krestan, C.; Gahleitner, A.; Marlovits, S.; Trattnig, S. [Department of Osteology, Universitaetklinik fuer Radiodiagnostik, AKH-Vienna, Waehringer Guertel 18-20, 1090 Vienna (Austria); Sulzbacher, I. [Universitaetsklinik fuer Pathologie Vienna, Waehringer Guertel 18-20, 1090 Vienna (Austria)

    2002-11-01

    With the introduction of fat-suppressed gradient-echo and fast spin-echo (FSE) sequences in clinical routine MR visualization of the hyaline articular cartilage is routinely possible in the larger joints. While 3D gradient-echo with fat suppression allows exact depiction of the thickness and surface of cartilage, FSE outlines the normal and abnormal internal structures of the hyaline cartilage; therefore, both sequences seem to be necessary in a standard MRI protocol for cartilage visualization. In diagnostically ambiguous cases, in which important therapeutic decisions are required, direct MR arthrography is the established imaging standard as an add-on procedure. Despite the social impact and prevalence, until recent years there was a paucity of knowledge about the pathogenesis of cartilage damage. With the introduction of high-resolution MRI with powerful surface coils and fat-suppression techniques, visualization of the articular cartilage is now routinely possible in many joints. After a short summary of the anatomy and physiology of the hyaline cartilage, the different MR imaging methods are discussed and recommended standards are suggested. (orig.)

  1. MRI in intraspinal tuberculosis

    Gupta, R.K. (Dept. of Radiology, Sanjay Gandhi Postgraduate Inst. of Medical Sciences, Lucknow (India)); Gupta, S. (Dept. of Radiology, Sanjay Gandhi Postgraduate Inst. of Medical Sciences, Lucknow (India)); Kumar, S. (Dept. of Radiology, Sanjay Gandhi Postgraduate Inst. of Medical Sciences, Lucknow (India)); Kohli, A. (Dept. of Neurology, Sanjay Gandhi Postgraduate Inst. of Medical Sciences, Lucknow (India)); Misra, U.K. (Dept. of Neurology, Sanjay Gandhi Postgraduate Inst. of Medical Sciences, Lucknow (India)); Gujral, R.B. (Dept. of Radiology, Sanjay Gandhi Postgraduate Inst. of Medical Sciences, Lucknow (India))

    1994-01-01

    We studied 20 patients with intraspinal tuberculosis (TB), to characterise the MRI features of tuberculous meningitis and myelitis. MRI leptomeningitis and intramedullary involvement in 11 patients, intramedullary lesions alone in 5, leptomeningitis alone in 2, and isolated extradural disease in 2. TB leptomeningitis was characterised by loculation of the cerebrospinal fluid (CSF), nerve root thickening and clumping (seen only in the lumbar region) or complete obliteration of the subarachnoid space on unenhanced images. Gd-DTPA-enhanced images proved useful in 6 cases, revealing linear enhancement of the surface of the spinal cord and nerve roots or plaque-like enhancement of the dura-arachnoid mater complex. Intramedullary lesions included tuberculomas (8), cord oedema (5) and cavitation (3). In seven cases of intramedullary tuberculoma multiple lesions with skip areas were seen, without significant cord swelling. One patient had an isolated lesion in the conus medullaris. The lesions were iso- or hypointense on T1-weighted images, iso-, hypo- or hyperintense on T2-weighted images and showed rim or nodular enhancement with contrast medium. (orig.)

  2. MRI of ranulas

    Kurabayashi, T.; Ida, M.; Ohbayashi, N.; Yoshino, N.; Tetsumura, A.; Sasaki, T. [Graduate School, Tokyo Medical and Dental Univ. (Japan); Yasumoto, M. [Dept. of Radiology, Tokyo Medical and Dental Univ. (Japan)

    2000-12-01

    We reviewed the MRI of 20 patients with a ranula (8 simple and 12 plunging) and ten with other cystic masses in the floor of the mouth and/ or suprahyoid portion of the neck (three haemangiomas, two neuromas, one monomorphic adenoma, one lipoma, two lateral cervical cysts and one dermoid cyst). Histological diagnoses were obtained in all cases with the exception of one presumed haemangioma. Ranulas were all well-defined, homogeneous masses giving low signal on T1-and markedly high signal on T2-weighted images. While simple ranulas were all confined to the sublingual space, plunging ranulas were centered on the submandibular space and tended to spill into one or more adjacent spaces. They extended into the sublingual space anteriorly (producung a so-called tail sign) in eight of 12 cases and into the parapharyngeal space superiorly in five. Although they sometimes filled a considerable part of the parapharyngeal space, displacement of surrounding muscles or vessels was usually slight, which was thought to reflect the nature of extravasation pseudocysts. All other cystic masses in our study had one or more MRI finding different from those of ranulas and could be easily differentiated from them. (orig.)

  3. MRI Findings In Dengue Encephalitis

    Ashraf V.V

    2004-01-01

    Full Text Available Neurological manifestations are rare in dengue fever. Two cases with encephalopathy and systemic features of dengue fever with abnormal CSF and MR imaging are reported. Striking MRI finding was bilateral symmetrical thalamic lesions similar to those reported in Japanese encephalitis. This report highlights that MRI findings can be similar in dengue and Japanese encephalitis.

  4. MRI atlas of ectopic endometriosis.

    Dallaudière, B; Salut, C; Hummel, V; Pouquet, M; Piver, P; Rouanet, J-P; Maubon, A

    2013-03-01

    Ectopic endometriosis is a common condition which is often underdiagnosed, where MRI can help make a diagnosis simply, non-invasively and without irradiation. However, imagery signs of it are enormously polymorphic with a wide range of possible locations. In this paper, we have tried to illustrate comprehensively all its MRI appearances depending on the different locations where it occurs.

  5. Molecular MRI of Atherosclerotic lesions

    Adel, Brigit den

    2013-01-01

    This thesis describes the use of MRI contrast agents and vessel wall parameters to image different stages of atherosclerosis. Chapter 2 summerizes different MRI contrast agents targeted towards vulnerable plaques that have been presented in literature. Chapter 3 illustrates accumulation of paramagn

  6. Postmortem MRI of bladder agenesis

    Barber, Brendan R. [St George' s Hospital, Radiology Department, London (United Kingdom); Weber, Martin A. [Great Ormond Street Hospital for Children, Department of Histopathology, London (United Kingdom); Bockenhauer, Detlef [Great Ormond Street Hospital for Children, Department of Nephrology, London (United Kingdom); Hiorns, Melanie P.; McHugh, Kieran [Great Ormond Street Hospital for Children, Radiology Department, London (United Kingdom)

    2011-01-15

    We report a 35-week preterm neonate with bladder agenesis and bilateral dysplastic kidneys. A suprapubic catheter was inadvertently inserted into one of the larger inferior cysts of the left dysplastic kidney. A postmortem MRI scan was performed with the findings being confirmed on autopsy. We are unaware of another postmortem MRI study demonstrating bladder agenesis. (orig.)

  7. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... bear denotes child-specific content. Related Articles and Media MR Angiography (MRA) Magnetic Resonance, Functional (fMRI) - Brain Head and Neck Cancer Treatment Brain Tumor Treatment Magnetic Resonance Imaging (MRI) Safety Alzheimer's Disease Head Injury Brain Tumors Images related to Magnetic ...

  8. Threats to ultra-high-field MRI

    Le Bihan, Denis

    2009-08-01

    In 2004 the European Commission (EC) adopted a directive restricting occupational exposure to electromagnetic fields. This directive (2004/40/CE), which examines the possible health risks of the electromagnetic fields from mobile phones, Wi-Fi, Bluetooth and other devices, concluded that upper limits on radiation and applied electromagnetic fields are necessary to prevent workers from suffering any undue acute health effects. But although not initially intended, the biggest impact of the directive could be on magnetic resonance imaging (MRI), which is used in hospitals worldwide to produce images of unrivalled quality of the brain and other soft tissues.

  9. Fast Reference-Based MRI

    Weizman, Lior; Ben-Basaht, Dafna

    2015-01-01

    In many clinical MRI scenarios, existing imaging information can be used to significantly shorten acquisition time or to improve Signal to Noise Ratio (SNR). In some cases, a previously acquired image can serve as a reference image, that may exhibit similarity to the image being acquired. Examples include similarity between adjacent slices in high resolution MRI, similarity between various contrasts in the same scan and similarity between different scans of the same patient. In this paper we present a general framework for utilizing reference images for fast MRI. We take into account that the reference image may exhibit low similarity with the acquired image and develop an iterative weighted approach for reconstruction, which tunes the weights according to the degree of similarity. Experiments demonstrate the performance of the method in three different clinical MRI scenarios: SNR improvement in high resolution brain MRI, utilizing similarity between T2-weighted and fluid-attenuated inversion recovery (FLAIR)...

  10. Visualizing electromagnetic vacuum by MRI

    Chandrashekar, Chandrika S; Chandrashekar, S; Taylor, Erika A; Taylor, Deanne M

    2016-01-01

    Based upon Maxwell's equations, it has long been established that oscillating electromagnetic (EM) fields incident upon a metal surface decay exponentially inside the conductor, leading to a virtual EM vacuum at sufficient depths. Magnetic resonance imaging (MRI) utilizes radiofrequency (r.f.) EM fields to produce images. Here we present the first visualization of an EM vacuum inside a bulk metal strip by MRI, amongst several novel findings. We uncover unexpected MRI intensity patterns arising from two orthogonal pairs of faces of a metal strip, and derive formulae for their intensity ratios. Further, we furnish chemical shift imaging (CSI) results that discriminate different faces (surfaces) of a metal block according to their distinct nuclear magnetic resonance (NMR) chemical shifts, which holds much promise for monitoring surface chemical reactions noninvasively. Bulk metals are ubiquitous, and MRI is a premier noninvasive diagnostic tool. Combining the two, the emerging field of bulk metal MRI can be expe...

  11. MRI appearances of inflammatory vertebral osteitis in early ankylosing spondylitis

    Kurugoglu, Sebuh; Kanberoglu, Kaya; Mihmanli, Ismail; Cokyuksel, Oktay [Department of Radiology, Cerrahpasa Medical Faculty, Istanbul University (Turkey); Kanberoglu, Ayfer [Department of Physical Medicine, SSK Istanbul Hospital, Istanbul (Turkey)

    2002-03-01

    Background: Undiagnosed and early ankylosing spondylitis (AS), especially in adolescent patients suffering from back pain, may present with the finding of vertebral osteitis on MRI. Aims: To identify the early MRI changes of vertebral osteitis in AS. Patients and methods: Five patients (three boys, two girls) aged 11-20 years (mean 15.4 years) suffering from back pain underwent MRI of the thoracolumbar spine. There was no initial diagnosis of AS. After clinical and radiological suspicion of AS, MRI of the sacroiliac (SI) joints was performed. Results: During the course of AS, destructive and reactive changes affect the discovertebral junctions that are initially seen in the thoracolumbar area. At this stage plain radiography of the spinal column may be normal. On MR images, inflammatory osteitis of the vertebrae is seen as hypointense areas on T1-weighted images and hyperintense areas on T2-W images. The lesions enhance homogenously with contrast material. Conclusions: Awareness of the MRI appearances of vertebral osteitis is helpful in suspecting AS. Radiological examination of the SI facilitates the diagnosis and unnecessary further imaging can be avoided. (orig.)

  12. MRI findings in Hirayama disease

    Raval Monali

    2010-01-01

    Full Text Available The objective of the study was to study the magnetic resonance imaging (MRI features of Hirayama disease on a 3 Tesla MRI scanner. Nine patients with clinically suspected Hirayama disease were evaluated with neutral position, flexion, contrast-enhanced MRI and fast imaging employing steady-state acquisition (FIESTA sequences. The spectrum of MRI features was evaluated and correlated with the clinical and electromyography findings. MRI findings of localized lower cervical cord atrophy (C5-C7, abnormal curvature, asymmetric cord flattening, loss of attachment of the dorsal dural sac and subjacent laminae in the neutral position, anterior displacement of the dorsal dura on flexion and a prominent epidural space were revealed in all patients on conventional MRI as well as with the dynamic 3D-FIESTA sequence. Intramedullary hyperintensity was seen in four patients on conventional MRI and on the 3D-FIESTA sequence. Flow voids were seen in four patients on conventional MRI sequences and in all patients with the 3D-FIESTA sequence. Contrast enhancement of the epidural component was noted in all the five patients with thoracic extensions. The time taken for conventional and contrast-enhanced MRI was about 30-40 min, while that for the 3D-FIESTA sequence was 6 min. Neutral and flexion position MRI and the 3D-FIESTA sequence compliment each other in displaying the spectrum of findings in Hirayama disease. A flexion study should form an essential part of the screening protocol in patients with suspected Hirayama disease. Newer sequences such as the 3D-FIESTA may help in reducing imaging time and obviating the need for contrast.

  13. fMRI adaptation revisited.

    Larsson, Jonas; Solomon, Samuel G; Kohn, Adam

    2016-07-01

    Adaptation has been widely used in functional magnetic imaging (fMRI) studies to infer neuronal response properties in human cortex. fMRI adaptation has been criticized because of the complex relationship between fMRI adaptation effects and the multiple neuronal effects that could underlie them. Many of the longstanding concerns about fMRI adaptation have received empirical support from neurophysiological studies over the last decade. We review these studies here, and also consider neuroimaging studies that have investigated how fMRI adaptation effects are influenced by high-level perceptual processes. The results of these studies further emphasize the need to interpret fMRI adaptation results with caution, but they also provide helpful guidance for more accurate interpretation and better experimental design. In addition, we argue that rather than being used as a proxy for measurements of neuronal stimulus selectivity, fMRI adaptation may be most useful for studying population-level adaptation effects across cortical processing hierarchies.

  14. MRI of plants and foods

    Van As, Henk; van Duynhoven, John

    2013-04-01

    The importance and prospects for MRI as applied to intact plants and to foods are presented in view of one of humanity's most pressing concerns, the sustainable and healthy feeding of a worldwide increasing population. Intact plants and foods have in common that their functionality is determined by complex multiple length scale architectures. Intact plants have an additional level of complexity since they are living systems which critically depend on transport and signalling processes between and within tissues and organs. The combination of recent cutting-edge technical advances and integration of MRI accessible parameters has the perspective to contribute to breakthroughs in understanding complex regulatory plant performance mechanisms. In food science and technology MRI allows for quantitative multi-length scale structural assessment of food systems, non-invasive monitoring of heat and mass transport during shelf-life and processing, and for a unique view on food properties under shear. These MRI applications are powerful enablers of rationally (re)designed food formulations and processes. Limitations and bottlenecks of the present plant and food MRI methods are mainly related to short T2 values and susceptibility artefacts originating from small air spaces in tissues/materials. We envisage cross-fertilisation of solutions to overcome these hurdles in MRI applications in plants and foods. For both application areas we witness a development where MRI is moving from highly specialised equipment to mobile and downscaled versions to be used by a broad user base in the field, greenhouse, food laboratory or factory.

  15. Pediatric Burkitt lymphoma presenting as acute pancreatitis: MRI characteristics

    Amodio, John; Brodsky, Jennie E. [SUNY Downstate Medical Center, Department of Radiology, Brooklyn, NY (United States)

    2010-05-15

    Acute pancreatitis is a rare initial presentation of non-Hodgkin lymphoma with few reported cases described in older adults and even fewer in children. MRI features of Burkitt lymphoma of the pancreas are sparse in the radiologic literature. We present a 6-year-old boy who presented with pancreatitis and obstructive jaundice, which was the result of Burkitt lymphoma of the pancreas. The imaging findings of pancreatic involvement of Burkitt lymphoma on MRI are discussed and the contributory role of the radiologist in guiding the appropriate clinical work-up of this disease is highlighted. (orig.)

  16. [Standartization of MRI studies in multiple sclerosis].

    Bryukhov, V V; Krotenkova, I A; Morozova, S N; Krotenkova, M V

    2016-01-01

    The use of magnetic resonance imaging (MRI) in patients with multiple sclerosis has markedly increased in recent years. The main task of the MRI studies after the diagnosis of multiple sclerosis is to assess the dynamics of MRI for determining disease progression and monitoring the efficacy of therapy. In this regard, it is very important to obtain the most identical baseline and follow-up MRI that is possible when a single standard protocol is used. This article presents the protocol of brain MRI and spinal cord MRI and interpretation of MRI studies in patients with multiple sclerosis.

  17. Tailored RF Pulse Modulation for RF Refocussed Variable Flip Angle MRI

    Shah, Ajit S.; Ortendahl, Douglas A.; Carlson, Joseph W.; Kramer, David M.; Crooks, Larry E.

    1989-05-01

    Advances in Magnetice Resonance Imaging (MRI) techniques have recently made MRI the imaging modality of choice for many applications of clinical imaging. MRI provides the diagnosing clinician a non-invasive method for obtaining soft tissue differentiation with sub-millimeter resolution. Clinical MRI techniques include 3-dimensional imaging, spectroscopic imaging, arterial angiography and cardiac imaging. One MRI technique which has recently gained popularity is a class of protocols known as variable/partial flip angle MRI. Partial flip angle MRI techniques are useful because of their ability to vary contrast between tissues and/or maintain a particular level of contrast with a reduction in acquisition time [1]. Variable flip angle techniques differ from conventional MRI protocols in that the initial RF excitation/rotation pulse is not constrained to a 90 degree rotation of the longitudinal magnetization. Instead, the initial excitation flip angle is calculated to provide improved contrast between two tissues and/or maximize the intensity of a particular tissue. For tissues with reduced TR/T1 ratios, variable flip angle techniques may also be used to increase the image signal to noise within a localized region.

  18. Value of multiparametric MRI in the work-up of prostate cancer.

    Cornud, F; Delongchamps, N B; Mozer, P; Beuvon, F; Schull, A; Muradyan, N; Peyromaure, M

    2012-02-01

    The role of magnetic resonance imaging (MRI) in prostate cancer evaluation is controversial and likely underestimated. Technological advances over the past 5 years have demonstrated that multiparametric MRI, including diffusion-weighted imaging (DWI) and dynamic contrast-enhanced MRI, can evaluate the actual tumor burden of a newly diagnosed prostate cancer more accurately than sextant biopsy protocols. Tumor risk, defined by the D'Amico criteria, hence can be re-evaluated by multiparametric MRI. As a result, there is increasing evidence that MRI before repeat or even initial biopsy can accurately select patients who require immediate biopsies and those in whom biopsy could be deferred. Also, a relationship between apparent diffusion coefficient (ADC), calculated from DWI, and Gleason score was found. Thus, MRI before biopsy helps to detect high-grade tumors to target biopsies within areas of low ADC values. To achieve good targeting accuracy, transrectal ultrasound (TRUS)-MRI image registration is necessary. Three-dimensional deformable registration is sufficiently accurate to match TRUS and MRI volumes with a topographic precision of 1 mm. Real-time MRI-guided biopsy is another technique under evaluation. Both approaches will allow for increasing acceptance of focal therapies, should these techniques be validated in the future.

  19. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... MRI scanners are air-conditioned and well-lit. Music may be played through the headphones to help ... page Additional Information and Resources RTAnswers.org : Radiation Therapy for Brain Tumors Radiation Therapy for Head and ...

  20. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... magnetic field is produced by passing an electric current through wire coils in most MRI units. Other ... that are detected by the coils. The electric current does not come in contact with the patient. ...

  1. Metalloprotein-based MRI probes.

    Matsumoto, Yuri; Jasanoff, Alan

    2013-04-17

    Metalloproteins have long been recognized as key determinants of endogenous contrast in magnetic resonance imaging (MRI) of biological subjects. More recently, both natural and engineered metalloproteins have been harnessed as biotechnological tools to probe gene expression, enzyme activity, and analyte concentrations by MRI. Metalloprotein MRI probes are paramagnetic and function by analogous mechanisms to conventional gadolinium or iron oxide-based MRI contrast agents. Compared with synthetic agents, metalloproteins typically offer worse sensitivity, but the possibilities of using protein engineering and targeted gene expression approaches in conjunction with metalloprotein contrast agents are powerful and sometimes definitive strengths. This review summarizes theoretical and practical aspects of metalloprotein-based contrast agents, and discusses progress in the exploitation of these proteins for molecular imaging applications.

  2. Magnetic Resonance Imaging (MRI) -- Head

    ... surgery pose no risk during MRI. However, a recently placed artificial joint may require the use of ... evaluation with additional views or a special imaging technique. A follow-up examination may also be necessary ...

  3. Magnetic Resonance Imaging (MRI) -- Head

    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 ...

  4. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... stroke infections developmental anomalies hydrocephalus — dilatation of fluid spaces within the brain (ventricles) causes of epilepsy (seizure) ... MRI. If you have claustrophobia (fear of enclosed spaces) or anxiety, you may want to ask your ...

  5. Magnetic Resonance Imaging (MRI) - Spine

    ... 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 ...

  6. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... tissue and fluid, known as edema . MRI typically costs more and may take more time to perform ... accredited facilities database . This website does not provide cost information. The costs for specific medical imaging tests, ...

  7. MRI of orbital hydroxyapatite implants

    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.)

  8. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... of the head uses a powerful magnetic field, radio waves and a computer to produce detailed pictures ... medical conditions. MRI uses a powerful magnetic field, radio frequency pulses and a computer to produce detailed ...

  9. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... any recent surgeries. Some conditions, such as severe kidney disease, may prevent you from being given gadolinium contrast ... an MRI. If you have a history of kidney disease or liver transplant, it will be necessary to ...

  10. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... intercom. Many MRI centers allow a friend or parent to stay in the room as long as they are also screened for safety in the magnetic environment. Children will be given appropriately sized earplugs or headphones ...

  11. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... scanner. top of page How does the procedure work? Unlike conventional x-ray examinations and computed tomography ( ... clearer and more detailed than with other imaging methods. This detail makes MRI an invaluable tool in ...

  12. MRI appearance of muscle denervation

    Kamath, S. [University Hospital of Wales, Department of Radiology, Cardiff (United Kingdom); Venkatanarasimha, N.; Walsh, M.A.; Hughes, P.M. [Derriford Hospital, Department of Radiology, Plymouth (United Kingdom)

    2008-05-15

    Muscle denervation results from a variety of causes including trauma, neoplasia, neuropathies, infections, autoimmune processes and vasculitis. Traditionally, the diagnosis of muscle denervation was based on clinical examination and electromyography. Magnetic resonance imaging (MRI) offers a distinct advantage over electromyography, not only in diagnosing muscle denervation, but also in determining its aetiology. MRI demonstrates characteristic signal intensity patterns depending on the stage of muscle denervation. The acute and subacutely denervated muscle shows a high signal intensity pattern on fluid sensitive sequences and normal signal intensity on T1-weighted MRI images. In chronic denervation, muscle atrophy and fatty infiltration demonstrate high signal changes on T1-weighted sequences in association with volume loss. The purpose of this review is to summarise the MRI appearance of denervated muscle, with special emphasis on the signal intensity patterns in acute and subacute muscle denervation. (orig.)

  13. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... may follow your regular daily routine and take food and medications as usual. Some MRI examinations may ... to iodine or x-ray contrast material, drugs, food, or the environment, or if you have asthma. ...

  14. Magnetic Resonance Imaging (MRI) -- Head

    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 ...

  15. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... magnetic field of the MRI unit, metal and electronic items are not allowed in the exam room. ... tell the technologist if you have medical or electronic devices in your body. These objects may interfere ...

  16. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... contrast for an MRI. If you have a history of kidney disease or liver transplant, it will ... Radiology (ACR) and the Radiological Society of North America (RSNA), comprising physicians with expertise in several radiologic ...

  17. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... can help diagnose conditions such as: brain tumors stroke infections developmental anomalies hydrocephalus — dilatation of fluid spaces ... MRA page for more information. MRI can detect stroke at a very early stage by mapping the ...

  18. MRI of the Musculoskeletal System

    ... receive injections of gadolinium contrast material except when absolutely necessary for medical treatment. See the Safety page ... MRI scanners are air-conditioned and well-lit. Music may be played through the headphones to help ...

  19. Magnetic Resonance Imaging (MRI) - Spine

    ... receive injections of gadolinium contrast material except when absolutely necessary for medical treatment. See the Safety page ... MRI scanners are air-conditioned and well-lit. Music may be played through the headphones to help ...

  20. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... Unless you are told otherwise, take your regular medications as usual. Leave jewelry at home and wear ... your regular daily routine and take food and medications as usual. Some MRI examinations may require you ...

  1. Resolution of NASH with weight loss documented by hepatic MRI.

    Singh, Vasvi; Luthra, Saurav; Elajami, Tarec K; Welty, Francine K

    2015-01-06

    A 57-year-old Asian woman with type 2 diabetes mellitus, hypertension, obesity, dyslipidaemia and history of breast cancer, was referred to the cardiovascular health and lipid centre for evaluation and management of dyslipidaemia and NASH (Non-alcoholic steatohepatitis) in 2010. She originally had a detailed work up at the liver clinic for elevated liver enzymes, with no associated symptoms. Initial hepatic MRI on 22 January 2007 showed diffuse fatty infiltration quantitated at 15%. We counselled her on lifestyle modifications, including dietary measures and exercise, geared toward weight loss. Over the next 2 years, she lost 24.5 lbs; repeat hepatic MRI on 22 December 2011 showed 6% hepatic fat, which is within the normal range. This case demonstrates the efficacy of significant weight loss in the improvement and resolution of NASH. We believe that this is the first case report documenting this through liver MRI.

  2. MRI in acute disseminated encephalomyelitis

    Caldemeyer, K.S. (Div. of Neuroradiology, Dept. of Radiology, Indiana Univ. School of Medicine, Indianapolis, IN (United States)); Smith, R.R. (Div. of Neuroradiology, Dept. of Radiology, Indiana Univ. School of Medicine, Indianapolis, IN (United States)); Harris, T.M. (Div. of Neuroradiology, Dept. of Radiology, Indiana Univ. School of Medicine, Indianapolis, IN (United States)); Edwards, M.K. (Div. of Neuroradiology, Dept. of Radiology, Indiana Univ. School of Medicine, Indianapolis, IN (United States))

    1994-04-01

    A retrospective analysis of CT and MRI studies in 12 patients with a clinical diagnosis of acute disseminated encephalomyelitis (ADEM) was performed. MRI was the definitive modality for the assessment of the lesions of ADEM: all patients had abnormalities consistent with the clinical diagnosis. Ten had abnormalities in the brain, three spinal cord lesions, and three showed evidence of optic neuritis. CT was normal in 6 of the 7 patients in which it was performed. (orig.)

  3. MRI and intraocular tamponade media

    Manfre, I. (Dept. of Neuroradiology, Inst. of Neurosurgery, Univ. of Catania (Italy)); Fabbri, G. (Dept. of Neuroradiology, Inst. of Neurosurgery, Univ. of Catania (Italy)); Avitabile, T. (Inst. of Ophthalmology, Univ. of Catania (Italy)); Biondi, P. (Inst. of Ophthalmology, Univ. of Catania (Italy)); Reibaldi, A. (Inst. of Ophthalmology, Univ. of Catania (Italy)); Pero, G. (Dept. of Neuroradiology, Inst. of Neurosurgery, Univ. of Catania (Italy))

    1993-05-01

    Thirteen patients who underwent surgery for retinal detachment and injection of intraocular tamponade media (silicone oil, flurosilicone oil, or perfluoro-carbon liquid) underwent magnetic resonance imaging (MRI), using spin-echo T1- and T2-weighted images. The ophthalmic tamponade media showed different signal intensity, according to their chemical structure. Unlike ophthalmoscopy or ultrasonography, MRI showed no oil-related artefact, making possible recognition of recurrent retinal detachment. (orig.)

  4. MRI evaluation of vascular dementia

    Yicheng Liu; Hongxing Zhang; Wei Huang; Wenjun Wan; Hongfen Peng

    2006-01-01

    OBJECTTVE: To explain the association between vascular dementia and the cranial MRI manifestations, and recognize the value of cranial MRI in the early diagnosis of vascular dementia and the assessment of disease conditions.DATA SOURCES: Pubmed database was searched to identify articles about the cranial MRI manifestations of patients with vascular dementia published in English from January 1992 to June 2006 by using the key words of "MRI, vascular dementia". Others were collected by searching the name of journals and title of articles in the Chinese full-text journal database.STUDY SELECTTON: The collected articles were primarily checked, those correlated with the cranial MRI manifestations of patients with vascular dementia were selected, while the obviously irrelative ones were excluded, and the rest were retrieved manually, the full-texts were searched.DATA EXTRACTION: Totally 255 articles were collected, 41 of them were involved, and the other 214 were excluded.DATA SYNTHESIS: MRI can be taken as one of the effective methods for the early diagnosis and disease evaluation of vascular dementia. White matter lesions are the important risk factors of vascular dementia.Vascular dementia is accompanied by the atrophy of related brain sites, but further confirmation is needed to investigate whether there is significant difference. MRI can be used to quantitatively investigate the infarcted sites and sizes of patients with vascular dementia after infarction, but there is still lack of systematic investigation on the association of the infarcted sites and sizes with the cognitive function of patients with vascular dementia.CONCLUSTON: Cranial MRI can detect the symptoms of vascular dementia at early period, so that corresponding measures can be adopted to prevent and treat vascular dementia in time.

  5. Congenital dacryocystocele: prenatal MRI findings

    Yazici, Zeynep [Cincinnati Children' s Hospital Medical Center, Department of Radiology, Cincinnati, OH (United States); Uludag University, Department of Radiology, Faculty of Medicine, Bursa (Turkey); Kline-Fath, Beth M.; Rubio, Eva I.; Calvo-Garcia, Maria A.; Linam, Leann E. [Cincinnati Children' s Hospital Medical Center, Department of Radiology, Cincinnati, OH (United States); Yazici, Bulent [Uludag University, Department of Ophthalmology, Faculty of Medicine, Bursa (Turkey)

    2010-12-15

    Congenital dacryocystocele can be diagnosed prenatally by imaging. Prenatal MRI is increasingly utilized for fetal diagnosis. To present the radiological and clinical features of seven fetuses with congenital dacryocystocele diagnosed with prenatal MRI. The institutional database of 1,028 consecutive prenatal MR examinations performed during a period of 4 years was reviewed retrospectively. The cases of congenital dacryocystocele were identified by reading the report of each MRI study. The incidence of dacryocystocele diagnosed with prenatal MRI was 0.7% (n=7/1,028). The dacryocystocele was bilateral in three fetuses. Mean gestational age at the time of diagnosis was 31 weeks. The indication for prenatal MRI was the presence or the suspicion of central nervous system abnormality in six fetuses and diaphragmatic hernia in one. Dacryocystocele was associated with an intranasal cyst in six of ten eyes. Prenatal sonography revealed dacryocystocele in only two of seven fetuses. Of eight eyes with postnatal follow-up, four did not have any lacrimal symptoms. Prenatal MRI can delineate congenital dacryocystocele more clearly and in a more detailed fashion than ultrasonography. Presence of dacryocystocele was symptomatic in only 50% of our patients, supporting that prenatal diagnosis of dacryocystocele might follow a benign course. (orig.)

  6. High resolution pituitary gland MRI at 7.0 tesla: a clinical evaluation in Cushing's disease

    Rotte, Alexandra A.J. de; Groenewegen, Amy; Rutgers, Dik R.; Witkamp, Theo; Luijten, Peter R.; Hendrikse, Jeroen [University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands); Zelissen, Pierre M.J. [University Medical Center Utrecht, Department of Internal Medicine (Section of Endocrinology), Utrecht (Netherlands); Meijer, F.J.A. [Radboud University Medical Center, Department of Radiology and Nuclear Medicine, Nijmegen (Netherlands); Lindert, Erik J. van [Radboud University Medical Center, Department of Neurosurgery, Nijmegen (Netherlands); Hermus, Ad [Radboud University Medical Center, Department of Internal Medicine (Section of Endocrinology), Nijmegen (Netherlands)

    2016-01-15

    To evaluate the detection of pituitary lesions at 7.0 T compared to 1.5 T MRI in 16 patients with clinically and biochemically proven Cushing's disease. In seven patients, no lesion was detected on the initial 1.5 T MRI, and in nine patients it was uncertain whether there was a lesion. Firstly, two readers assessed both 1.5 T and 7.0 T MRI examinations unpaired in a random order for the presence of lesions. Consensus reading with a third neuroradiologist was used to define final lesions in all MRIs. Secondly, surgical outcome was evaluated. A comparison was made between the lesions visualized with MRI and the lesions found during surgery in 9/16 patients. The interobserver agreement for lesion detection was good at 1.5 T MRI (κ = 0.69) and 7.0 T MRI (κ = 0.62). In five patients, both the 1.5 T and 7.0 T MRI enabled visualization of a lesion on the correct side of the pituitary gland. In three patients, 7.0 T MRI detected a lesion on the correct side of the pituitary gland, while no lesion was visible at 1.5 T MRI. The interobserver agreement of image assessment for 7.0 T MRI in patients with Cushing's disease was good, and lesions were detected more accurately with 7.0 T MRI. (orig.)

  7. MRI and ultrasound in children with juvenile chronic arthritis

    Lamer, S.; Sebag, G.H

    2000-02-01

    In this era of advancing imaging technology, a knowledge of the relative values of available imaging techniques is necessary to optimize the management of children with juvenile chronic arthritis (JCA). After clinical examination, plain films remain the initial investigation. The need for radiation protection must be a priority in children with JCA. Conventional radiographs allow grouping of the various arthritides (on the base of the distribution and pattern of joint space changes) and staging of disease progression. Ultrasound (US) is very sensitive in the detection of joint effusions, especially in the hip, and guides fluid aspiration. US and Doppler can be used for the evaluation of synovial hypertrophy and activity. Arthrography and to a certain extent nuclear studies have been replaced by magnetic resonance imaging (MRI). MRI can demonstrate articular cartilage, joint effusion, synovial hypertrophy, cortical and medullary bone, cartilage and bone perfusion, and fibrocartilaginous structures (menisci and ligaments). Contrast enhanced MRI is the most sensitive modality to determine whether an arthritic condition is present. However, it does not assist in establishing a specific diagnosis. MRI determines accurately the activity and the extent of the disease and is particularly useful in the early detection of articular damage. Finally, MRI is of major importance in the evaluation of response to local therapy (especially steroids) and the detection of complications.

  8. MRI of occult sacral insufficiency fractures following radiotherapy

    Mammone, J.F. [Dept. of Radiology, Thomas Jefferson Univ. Hospital, and Jefferson Medical Coll., Philadelphia, PA (United States); Schweitzer, M.E. [Dept. of Radiology, Thomas Jefferson Univ. Hospital, and Jefferson Medical Coll., Philadelphia, PA (United States)

    1995-02-01

    Following radiation therapy, marrow abnormalities noted on magnetic resonance imaging (MRI) are frequent and may mimic metastases. Specific radiotherapy changes are usually easily identifiable; however, traumatic lesions cause more interpretive difficulties. We assessed the incidence and MRI characteristics of insufficiency fractures in this population. During a 5-year span (1987-1991), 546 patients received pelvic radiotherapy for primary malignancies. MRI was performed in 25 of these patients at least 3 months after treatment. The mean dose in this group was 53 Gy. These MRI scans were retrospectively reviewed for the appearance of the sacrum with particular attention to the presence of insufficiency fractures. This was correlated with clinical course and scintigraphic findings. Presumed insufficiency fractures on MRI paralleled the sacral side of the sacroiliac joint, enhanced with Gd-DTPA, were most prominent or initially seen anteriorly, and had ill-defined margins on all imaging sequences. The incidence of occult sacral insufficiency fractures was at least 20%. Insufficiency fractures of the sacrum in the post-radiotherapy patient are a relatively frequent occurrence which can mimic metastases. Consideration of this phenomenon and knowledge of differential features may avoid overdiagnosis of osseous metastases. (orig.)

  9. Prospective detection of cortical dysplasia on clinical MRI in pediatric intractable epilepsy

    Radhakrishnan, Rupa; Leach, James L.; Gelfand, Michael J. [Cincinnati Children' s Hospital Medical Center, Department of Radiology, Cincinnati, OH (United States); Mangano, Francesco T. [Cincinnati Children' s Hospital Medical Center, Department of Neurosurgery, Cincinnati, OH (United States); Rozhkov, Leonid; Greiner, Hansel M. [Cincinnati Children' s Hospital Medical Center, Department of Neurology, Comprehensive Epilepsy Treatment Center, Cincinnati, OH (United States); Miles, Lili [Cincinnati Children' s Hospital Medical Center, Department of Pathology, Cincinnati, OH (United States)

    2016-09-15

    Cortical dysplasia is the most common cause of pediatric refractory epilepsy. MRI detection of epileptogenic lesion is associated with good postsurgical outcome. Additional electrophysiological information is suggested to be helpful in localization of cortical dysplasia. Educational measures were taken to increase the awareness of cortical dysplasia at our institution in the context of a recent International League Against Epilepsy (ILAE 2011) classification of cortical dysplasia. To determine changes in the rate of prospective identification of cortical dysplasia on an initial radiology report and also evaluate the benefit of MRI review as part of a multidisciplinary epilepsy conference in identifying previously overlooked MRI findings. We retrospectively evaluated surgically treated children with refractory epilepsy from 2007 to 2014 with cortical dysplasia on histopathology. We analyzed the initial radiology report, preoperative MRI interpretation at multidisciplinary epilepsy conference and subsequent retrospective MRI review with knowledge of the resection site. We recorded additional electrophysiological data and the presence of lobar concordance with the MRI findings. Of 78 children (44 MRI lesional) evaluated, 18 had initially overlooked MRI findings. Comparing 2007-2010 to 2011-2014, there was improvement in the rate of overlooked findings on the initial radiology report (54% vs. 13% of lesional cases, respectively; P = 0.008). The majority (72%) were identified at a multidisciplinary conference with lobar concordance of findings with at least one additional electrophysiological investigation in 89%. Awareness of current classification schemes of cortical dysplasia and image review in the context of a multidisciplinary conference can lead to improved MRI detection of cortical dysplasia in children. (orig.)

  10. 3D Dynamical Modeling of Wind Accretion in Cyg X-3

    Okazaki, Atsuo T

    2014-01-01

    Cyg X-3 is a high mass X-ray binary consisting of a Wolf-Rayet star and a compact object in a very short orbital period of 4.8h. The only confirmed microquasar with high energy gamma-ray emission, Cyg X-3 provides a unique opportunity to study the relationship between the accretion power and the power in high energy emission. Because of a compact orbit and a slow Wolf-Rayet wind, the flow structure around the compact object is thought to be strongly affected by the orbital motion, details of which can be obtained only by numerical simulations. In this paper, we report on the results from 3D hydrodynamic simulations of the wind accretion in Cyg X-3. For simplicity we adopt an anti-gravity-like force that emulates the radiative acceleration consistent with the beta-velocity wind. Due to the rapid orbital motion, the flow around the compact object has large density gradients. As a result, the accretion rate onto the compact object is significantly lower than that of the Bondi-Hoyle-Lyttleton rate. We also calcul...

  11. KMOS3D: Dynamical Constraints on the Mass Budget in Early Star-forming Disks

    Wuyts, Stijn; Förster Schreiber, Natascha M.; Wisnioski, Emily; Genzel, Reinhard; Burkert, Andreas; Bandara, Kaushala; Beifiori, Alessandra; Belli, Sirio; Bender, Ralf; Brammer, Gabriel B.; Chan, Jeffrey; Davies, Ric; Fossati, Matteo; Galametz, Audrey; Kulkarni, Sandesh K.; Lang, Philipp; Lutz, Dieter; Mendel, J. Trevor; Momcheva, Ivelina G.; Naab, Thorsten; Nelson, Erica J.; Saglia, Roberto P.; Seitz, Stella; Tacconi, Linda J.; Tadaki, Ken-ichi; Übler, Hannah; van Dokkum, Pieter G.; Wilman, David J.; Wuyts, Eva

    2016-11-01

    We exploit deep integral-field spectroscopic observations with KMOS/Very Large Telescope of 240 star-forming disks at 0.6\\lt z\\lt 2.6 to dynamically constrain their mass budget. Our sample consists of massive (≳ {10}9.8 {M}⊙ ) galaxies with sizes {R}e≳ 2 {kpc}. By contrasting the observed velocity and dispersion profiles with dynamical models, we find that on average the stellar content contributes {32}-7+8 % of the total dynamical mass, with a significant spread among galaxies (68th percentile range {f}{star}˜ 18 % {--}62 % ). Including molecular gas as inferred from CO- and dust-based scaling relations, the estimated baryonic mass adds up to {56}-12+17 % of the total for the typical galaxy in our sample, reaching ˜ 90 % at z\\gt 2. We conclude that baryons make up most of the mass within the disk regions of high-redshift star-forming disk galaxies, with typical disks at z\\gt 2 being strongly baryon-dominated within R e . Substantial object-to-object variations in both stellar and baryonic mass fractions are observed among the galaxies in our sample, larger than what can be accounted for by the formal uncertainties in their respective measurements. In both cases, the mass fractions correlate most strongly with measures of surface density. High-{{{Σ }}}{star} galaxies feature stellar mass fractions closer to unity, and systems with high inferred gas or baryonic surface densities leave less room for additional mass components other than stars and molecular gas. Our findings can be interpreted as more extended disks probing further (and more compact disks probing less far) into the dark matter halos that host them. Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere under ESO programs 092.A-0091, 093.A-0079, 094.A-0217, 095.A-0047, and 096.A-0025.

  12. Face recognition based on matching of local features on 3D dynamic range sequences

    Echeagaray-Patrón, B. A.; Kober, Vitaly

    2016-09-01

    3D face recognition has attracted attention in the last decade due to improvement of technology of 3D image acquisition and its wide range of applications such as access control, surveillance, human-computer interaction and biometric identification systems. Most research on 3D face recognition has focused on analysis of 3D still data. In this work, a new method for face recognition using dynamic 3D range sequences is proposed. Experimental results are presented and discussed using 3D sequences in the presence of pose variation. The performance of the proposed method is compared with that of conventional face recognition algorithms based on descriptors.

  13. 3D dynamic rupture with anelastic wave propagation using an hp-adaptive Discontinuous Galerkin method

    Tago, J.; Cruz-Atienza, V. M.; Etienne, V.; Virieux, J.; Benjemaa, M.; Sanchez-Sesma, F. J.

    2010-12-01

    Simulating any realistic seismic scenario requires incorporating physical basis into the model. Considering both the dynamics of the rupture process and the anelastic attenuation of seismic waves is essential to this purpose and, therefore, we choose to extend the hp-adaptive Discontinuous Galerkin finite-element method to integrate these physical aspects. The 3D elastodynamic equations in an unstructured tetrahedral mesh are solved with a second-order time marching approach in a high-performance computing environment. The first extension incorporates the viscoelastic rheology so that the intrinsic attenuation of the medium is considered in terms of frequency dependent quality factors (Q). On the other hand, the extension related to dynamic rupture is integrated through explicit boundary conditions over the crack surface. For this visco-elastodynamic formulation, we introduce an original discrete scheme that preserves the optimal code performance of the elastodynamic equations. A set of relaxation mechanisms describes the behavior of a generalized Maxwell body. We approximate almost constant Q in a wide frequency range by selecting both suitable relaxation frequencies and anelastic coefficients characterizing these mechanisms. In order to do so, we solve an optimization problem which is critical to minimize the amount of relaxation mechanisms. Two strategies are explored: 1) a least squares method and 2) a genetic algorithm (GA). We found that the improvement provided by the heuristic GA method is negligible. Both optimization strategies yield Q values within the 5% of the target constant Q mechanism. Anelastic functions (i.e. memory variables) are introduced to efficiently evaluate the time convolution terms involved in the constitutive equations and thus to minimize the computational cost. The incorporation of anelastic functions implies new terms with ordinary differential equations in the mathematical formulation. We solve these equations using the same order of interpolation as for the elastic equations (i.e. the so-called P0, P1 or P2 interpolations functions). We compare solutions from several numerical strategies (e.g. Finite Difference and Discontinuous Galerkin methods). For the second extension, the dynamic rupture formulation requires explicit boundary conditions on discontinuous surface edges bounding the fracture. These conditions have been implemented for the different interpolation orders we consider and are based on the conservation of a discrete energy. The fault shear stress follows a linear slip-weakening law, although any other friction law could be implemented. We validate our mathematical and computational model by comparing synthetic seismograms with those yielded by the semi-analytical Discrete Wavenumber method for the attenuation effect and with a well-verified Finite Difference method (SGSN) for the dynamic rupture model. This work will allow us shortly to perform realistic simulations of possible physics-based seismic scenarios in the Valley of Mexico to study the associated hazard.

  14. Integrated Navigation, Guidance, and Control of Missile Systems: 3-D Dynamic Model

    2013-02-01

    subsequently computing the elements of the transformation (direction cosine) matrix. We shall utilise the quaternion algebra [5] to achieve this...Navigation A fuller exposition on quaternion algebra is given in [5]; in this section the main results are utilised for the navigation model for...ibfT for the ith vehicle may be written as:              i33i31 i23i22i21 i13i12i11 i b f t32tt ttt ttt T (2.27) Where: the elements

  15. KMOS^3D: Dynamical constraints on the mass budget in early star-forming disks

    Wuyts, S; Wisnioski, E; Genzel, R; Burkert, A; Bandara, K; Beifiori, A; Belli, S; Bender, R; Brammer, G B; Chan, J; Davies, R; Fossati, M; Galametz, A; Kulkarni, S K; Lang, P; Lutz, D; Mendel, J T; Momcheva, I G; Naab, T; Nelson, E J; Saglia, R P; Seitz, S; Tacconi, L J; Tadaki, K; Übler, H; van Dokkum, P G; Wilman, D J; Wuyts, E

    2016-01-01

    We exploit deep integral-field spectroscopic observations with KMOS/VLT of 240 star-forming disks at 0.6 2 being strongly baryon-dominated within $R_e$. Substantial object-to-object variations in both stellar and baryonic mass fractions are observed among the galaxies in our sample, larger than what can be accounted for by the formal uncertainties in their respective measurements. In both cases, the mass fractions correlate most strongly with measures of surface density. High $\\Sigma_{star}$ galaxies feature stellar mass fractions closer to unity, and systems with high inferred gas or baryonic surface densities leave less room for additional mass components other than stars and molecular gas. Our findings can be interpreted as more extended disks probing further (and more compact disks probing less far) into the dark matter halos that host them. However, a non-negligible tail of the derived baryonic mass fraction distribution reaching into the unphysical $f_{bar} > 1$ regime may in addition hint at more effi...

  16. The 1999 Izmit, Turkey, earthquake: A 3D dynamic stress transfer model of intraearthquake triggering

    Harris, R.A.; Dolan, J.F.; Hartleb, R.; Day, S.M.

    2002-01-01

    Before the August 1999 Izmit (Kocaeli), Turkey, earthquake, theoretical studies of earthquake ruptures and geological observations had provided estimates of how far an earthquake might jump to get to a neighboring fault. Both numerical simulations and geological observations suggested that 5 km might be the upper limit if there were no transfer faults. The Izmit earthquake appears to have followed these expectations. It did not jump across any step-over wider than 5 km and was instead stopped by a narrower step-over at its eastern end and possibly by a stress shadow caused by a historic large earthquake at its western end. Our 3D spontaneous rupture simulations of the 1999 Izmit earthquake provide two new insights: (1) the west- to east-striking fault segments of this part of the North Anatolian fault are oriented so as to be low-stress faults and (2) the easternmost segment involved in the August 1999 rupture may be dipping. An interesting feature of the Izmit earthquake is that a 5-km-long gap in surface rupture and an adjacent 25° restraining bend in the fault zone did not stop the earthquake. The latter observation is a warning that significant fault bends in strike-slip faults may not arrest future earthquakes.

  17. A Novel Flow-Perfusion Bioreactor Supports 3D Dynamic Cell Culture

    Alexander M. Sailon

    2009-01-01

    Full Text Available Background. Bone engineering requires thicker three-dimensional constructs than the maximum thickness supported by standard cell-culture techniques (2 mm. A flow-perfusion bioreactor was developed to provide chemotransportation to thick (6 mm scaffolds. Methods. Polyurethane scaffolds, seeded with murine preosteoblasts, were loaded into a novel bioreactor. Control scaffolds remained in static culture. Samples were harvested at days 2, 4, 6, and 8 and analyzed for cellular distribution, viability, metabolic activity, and density at the periphery and core. Results. By day 8, static scaffolds had a periphery cell density of 67%±5.0%, while in the core it was 0.3%±0.3%. Flow-perfused scaffolds demonstrated peripheral cell density of 94%±8.3% and core density of 76%±3.1% at day 8. Conclusions. Flow perfusion provides chemotransportation to thick scaffolds. This system may permit high throughput study of 3D tissues in vitro and enable prefabrication of biological constructs large enough to solve clinical problems.

  18. Toward a 3D dynamic model of a faulty duplex ball bearing

    Kogan, Gideon; Klein, Renata; Kushnirsky, Alex; Bortman, Jacob

    2015-03-01

    Bearings are vital components for safe and proper operation of machinery. Increasing efficiency of bearing diagnostics usually requires training of health and usage monitoring systems via expensive and time-consuming ground calibration tests. The main goal of this research, therefore, is to improve bearing dynamics modeling tools in order to reduce the time and budget needed to implement the health and usage monitoring approach. The proposed three-dimensional ball bearing dynamic model is based on the classic dynamic and kinematic equations. Interactions between the bodies are simulated using non-linear springs combined with dampers described by Hertz-type contact relation. The force friction is simulated using the hyperbolic-tangent function. The model allows simulation of a wide range of mechanical faults. It is validated by comparison to known bearing behavior and to experimental results. The model results are verified by demonstrating numerical convergence. The model results for the two cases of single and duplex angular ball bearings with axial deformation in the outer ring are presented. The qualitative investigation provides insight into bearing dynamics, the sensitivity study generalizes the qualitative findings for similar cases, and the comparison to the test results validates model reliability. The article demonstrates the variety of the cases that the 3D bearing model can simulate and the findings to which it may lead. The research allowed the identification of new patterns generated by single and duplex bearings with axially deformed outer race. It also enlightened the difference between single and duplex bearing manifestation. In the current research the dynamic model enabled better understanding of the physical behavior of the faulted bearings. Therefore, it is expected that the modeling approach has the potential to simplify and improve the development process of diagnostic algorithms. • A deformed outer race of a single axially loaded bearing is simulated. • The model results are subjected to a sensitivity study. • Duplex bearing with deformed outer race is simulated as well as tested. • The simulation results are in a good agreement with the experimental results.

  19. Semicircular canal dehiscence: comparison of T2-weighted turbo spin-echo MRI and CT

    Krombach, G.A.; Schmitz-Rode, T.; Haage, P.; Guenther, R.W. [Department of Diagnostic Radiology, University of Technology, Pauwelstrasse 30, 52057, Aachen (Germany); DiMartino, E. [Department of Otorhinolaryngology, University of Technology, Pauwelstrasse 30, 52057, Aachen (Germany); Prescher, A. [Department of Anatomy, University of Technology, Pauwelstrasse 30, 52057, Aachen (Germany); Kinzel, S. [Department of Experimental Veterinary Medicine, University of Technology, Pauwelstrasse 30, 52057, Aachen (Germany)

    2004-04-01

    We assessed the value of MRI for delineation of dehiscence of the superior or posterior semicircular canal, as compared with CT, the current standard study for this entity. We reviewed heavily T2-weighted fast spin-echo images and high-resolution CT of the temporal bones of 185 patients independently semicircular canal dehiscence and its extent. In 30 patients (19 men, 11 women) we identified dehiscence of the bone over the superior and/or posterior semicircular canal on MRI. In 27 of these cases CT also showed circumscribed bone defects. In one patient dehiscence of the superior semicircular canal was initially overlooked on MRI, but seen on CT. MRI imaging thus had a sensitivity of 96% and specificity of 98%. Knowledge of the appearances of this entity on MRI may contribute to early diagnosis in patients with vertigo due to semicircular canal dehiscence. (orig.)

  20. Changes underlying the dynamic contrast-enhanced MRI response to treatment in rheumatoid arthritis

    Hodgson, Richard J. [University of Liverpool, MARIARC, Liverpool (United Kingdom); Barnes, Theresa; Moots, Robert [University of Aintree, Clinical Rheumatology, School of Clinical Sciences, Liverpool (United Kingdom); Connolly, Sylvia [Whiston Hospital, Merseyside (United Kingdom); Eyes, Brian [University Hospital Aintree, Liverpool (United Kingdom); Campbell, Robert S.D. [Royal Liverpool Hospital, Liverpool (United Kingdom)

    2008-03-15

    Dynamic contrast-enhanced MRI of patients with rheumatoid arthritis has shown a decrease in the early enhancement rate (EER) of synovitis after treatment. The purpose of this work was to investigate the underlying changes. 3D dynamic contrast-enhanced images were acquired from 13 patients before and 1-2 weeks after anti-TNF{alpha} treatment. The EER of the inflamed synovium was measured. The T{sub 1} relaxation time of the synovitis was calculated from images at different flip angles. The time course of the arrival of gadolinium at the radial artery was determined. The gadolinium enhancement of the inflamed synovium was modeled to calculate the fractional plasma volume (v{sub p}), the fractional extravascular, extracellular fluid volume (v{sub e}), and the volume transfer constant (K{sup trans}). Pre- and post-treatment values were compared and the dependence of the EER on each parameter was assessed. There was a decrease in the EER measured over 26 s after treatment (29%, p = 0.002). Reductions in T{sub 1} (12%, p = 0.001), K{sup trans} (31%, p = 0.002), and v{sub p} (43%, p = 0.01) contributed to this; however, the EER was relatively insensitive to changes in v{sub e}. The decrease in EER after anti-TNF{alpha} treatment is largely caused by reductions in the volume transfer constant K{sup trans}, the fractional plasma volume v{sub p}, and the T{sub 1} relaxation time. Only the contributions from K{sup trans} and v{sub p} directly reflect synovial vascularity. (orig.)

  1. MRI in necrotizing fasciitis of the extremities.

    Ali, S Z; Srinivasan, S; Peh, W C G

    2014-01-01

    Necrotizing fasciitis is a life-threatening soft-tissue infection of bacterial origin, which involves mainly the deep fascia. Early recognition of this condition may be hampered by the uncommon nature of the disease and non-specificity of initial clinical signs and symptoms in less fulminant cases, making the role of imaging important. MRI is the most useful imaging modality in the diagnosis of necrotizing fasciitis. The presence of thick (>3 mm) hyperintense signal in the deep fascia (particularly intermuscular fascia) on fat-suppressed T2 weighted or short tau inversion-recovery images is an important marker for necrotizing fasciitis. Contrast enhancement of the thickened necrotic fascia can be variable, with a mixed-pattern of enhancement being more commonly encountered. Involvement of multiple musculofascial compartments increases the likelihood of necrotizing fasciitis. It is important to remember that T2-hyperintense signal in the deep fascia is not specific to necrotizing fasciitis and can also be seen in cases such as non-infective inflammatory fasciitis or muscle tear. In this pictorial essay, we aim to review the MRI findings in necrotizing fasciitis, discuss its limitations and pitfalls and identify differentiating features from non-necrotizing soft-tissue infections, such as cellulitis and infective myositis/pyomyositis, conditions which may clinically mimic necrotizing fasciitis.

  2. Ultrahigh Field NMR and MRI: Science at a Crossroads Workshop Report

    Polenova, Tatyana [Univ. of Delaware, Newark, DE (United States); Budinger, Thomas F. [Univ. of California, Berkeley, CA (United States)

    2016-01-04

    The workshop “Ultrahigh Field NMR and MRI: Science at Crossroads”, initiated by the scientific community and supported by the National Science Foundation, the Department of Energy, and the National Institutes of Health, took place on November 12-13, 2015, in Bethesda, MD, on the NIH campus. The meeting was held to assess the science drivers, technological challenges, prospects for achieving field strengths for NMR and MRI nearly double their current value, and strategies on how to provide ultrahigh field NMR/MRI capabilities to a national user community.

  3. Interstitial pregnancy: role of MRI

    Filhastre, M.; Lesnik, A. [Lapeyronie Hospital, Department of Radiology, Montpellier Cedex 5 (France); Dechaud, H.; Taourel, P. [Arnaud de Villeneuve Hospital, Department of Gynecology, Montpellier (France)

    2005-01-01

    We report the MRI features of two cases of interstitial pregnancy. In both cases, MRI was able to localize the ectopic pregnancy by showing a gestational structure surrounded by a thick wall in the upper part of the uterine wall separated from the endometrium by an uninterrupted junctional zone. Because US may confuse angular and interstitial pregnancies and because interstitial pregnancy has a particular evolutive course, MR imaging may play a key role in the diagnosis and management of women with interstitial pregnancy. (orig.)

  4. MRI in Optic Neuritis: Structure, Function, Interactions

    Fuglø, Dan

    2011-01-01

    resonance imaging (MRI), and the visual evoked potential (VEP) continues to show a delayed P100 indicating persistent demyelination. The explanation for this apparent discrepancy between structure and function could be due to either a redundancy in the visual pathways so that some degree of signal loss...... are low. Functional MRI (fMRI) is a non-invasive technique that can measure brain activity with a high spatial resolution. Recently, technical and methodological advancements have made it feasible to record VEPs and fMRI simultaneously and the relationship between averaged VEPs and averaged fMRI signals...... have been described. Still, to take full advantage of simultaneously recorded VEP-fMRI one would ideally want to track single-trial changes in the VEP and use this information in the fMRI analysis. In order to do this we examined 10 healthy volunteers with simultaneous VEP-fMRI. Different measures...

  5. MRI changes in the central nervous system in a child with lupus erythematosus

    Gieron, M.A. [Dept. of Pediatrics, Univ. of South Florida, Coll. of Medicine, Tampa, FL (United States); Khoromi, S. [Dept. of Neurology, Univ. of South Florida, Coll. of Medicine, Tampa, FL (United States); Campos, A. [Dept. of Pediatrics, Univ. of South Florida, Coll. of Medicine, Tampa, FL (United States)

    1995-05-01

    We report on a 10-year-old girl with systemic lupus erythematosus who presented in status epilepticus as the only manifestation of central nervous system involvement. MRI of the brain showed diffuse gray and white matter lesions which almost completely resolved after treatment with methylprednisolone. MRI findings in this child are similar to those in adults with diffuse clinical manifestations. The study is essential in the initial evaluation of patients suspected of central nervous system lupus. (orig.)

  6. Structural MRI of Pediatric Brain Development: What Have We Learned and Where Are We Going?

    2010-01-01

    Magnetic resonance imaging (MRI) allows unprecedented access to the anatomy and physiology of the developing brain without the use of ionizing radiation. Over the past two decades, thousands of brain MRI scans from healthy youth and those with neuropsychiatric illness have been acquired and analyzed with respect to diagnosis, sex, genetics, and/or psychological variables such as IQ. Initial reports comparing size differences of various brain components averaged across large age spans have giv...

  7. MRI and neurological findings in patients with spinal metastases

    Switlyk, M.D.; Hole, K.H.; Knutstad, K. [Department of Radiology and Nuclear Medicine, Oslo University Hospital, Norwegian Radium Hospital, Oslo (Norway)], E-mail: marta.switlyk@radiumhospitalet.no; Skjeldal, S.; Zaikova, O. [Department of Orthopedics, Oslo University Hospital, Norwegian Radium Hospital, Oslo (Norway); Hald, J.K. [Department of Radiology and Nuclear Medicine, Oslo University Hospital, Rikshospitalet, Oslo (Norway); Seierstad, T. [Department of Radiology and Nuclear Medicine, Oslo University Hospital, Norwegian Radium Hospital, Oslo (Norway); Faculty of Health Sciences, Buskerud University College, Drammen (Norway)

    2012-12-15

    Background. Magnetic resonance imaging (MRI) is the recommended primary investigation method for metastatic spinal cord compression (MSCC). Initiating treatment before the development of motor deficits is essential to preserve neurological function. However, the relationship between MRI-assessed grades of spinal metastatic disease and neurological status has not been widely investigated. Purpose. To analyze the association between neurological function and MRI-based assessment of the extent of spinal metastases using two different grading systems. Material and Methods. A total of 284 patients admitted to our institution for initial radiotherapy or surgery for symptomatic spinal metastases were included in the study. Motor and sensory deficits were categorized according to the Frankel classification system. Pre-treatment MRI evaluations of the entire spine were scored for the extent of spinal metastases, presence and severity of spinal cord compression, and nerve root compression. Two MRI-based scales were used to evaluate the degree of cord compression and spinal canal narrowing and relate these findings to neurological function. Results. Of the patients included in the study, 28 were non-ambulatory, 49 were ambulatory with minor motor deficits, and 207 had normal motor function. Spinal cord compression was present in all patients with Frankel scores of B or C, 23 of 35 patients with a Frankel score of D (66%), and 48 of 152 patients with a Frankel score of E (32%). The percentage of patients with severe spinal canal narrowing increased with increasing Frankel grades. The grading according to the scales showed a significant association with the symptoms according to the Frankel scale (P < 0.001). Conclusion. In patients with neurological dysfunction, the presence and severity of impairment was associated with the epidural tumor burden. A significant number of patients had radiological spinal cord compression and normal motor function (occult MSCC)

  8. Moyamoya disease: diagnostic accuracy of MRI

    Yamada, I. [Dept. of Radiology, Faculty of Medicine, Tokyo Medical and Dental Univ. (Japan); Suzuki, [Dept. of Radiology, Faculty of Medicine, Tokyo Medical and Dental Univ. (Japan); Matsushima, Y. [Dept. of Neurosurgery, Faculty of Medicine, Tokyo Medical and Dental Univ. (Japan)

    1995-07-01

    MRI may be employed to investigate moyamoya disease, since it provides vascular information without use of contrast medium. We reported the usefulness and limitations of MR angiography (MRA) in moyamoya disease. To our knowledge, no report has appeared dealing with the diagnostic accuracy of MRI in a large number of cases of moyamoya disease, although MRI is used more commonly than MRA. We therefore undertook to evaluate the accuracy of MRI in moyamoya disease. (orig.)

  9. Breast MRI in high risk patients

    A.I.M. Obdeijn (Inge-Marie)

    2015-01-01

    markdownabstractAbstract In this thesis we address various indications of breast MRI, with the emphasis on the value of MRI in screening of women with high genetic risk for breast cancer, and especially in BRCA1 mutation carriers. We showed that in the era of up-to-date MRI expertise and digital

  10. MRI of medulloblastoma in adults

    Malheiros, S.M.F.; Santos, A.J.; Borges, L.R.R.; Guimaraes, I.F.; Franco, C.M.R.; Gabbai, A.A. [Department of Neurology, Universidade Federal de Sao Paulo Rua Botucatu 740, SP 04023-900, Sao Paulo (Brazil); Carrete, H. [Department of Radiology, Universidade Federal de Sao Paulo Rua Botucatu 740, SP 04023-900, Sao Paulo (Brazil); Stavale, J.N.; Pelaez, M.P. [Department of Pathology, Universidade Federal de Sao Paulo Rua Botucatu 740, SP 04023-900, Sao Paulo (Brazil)

    2003-07-01

    Medulloblastoma has variable appearances on MRI in both children and adults. Adults are more likely to have heterogeneous cerebellar hemisphere tumours, and this is thought to be related to the greater prevalence of desmoplastic tumours in adulthood. Few studies have addressed the MRI features of adult medulloblastoma and the specific characteristics of desmoplastic and classic tumours have not been analysed. Our aim was to analyse the imaging characteristics of desmoplastic (DM) and classic (CM) medulloblastomas in adult. We retrospectively studied preoperative MRI of six men and three women, median age 33 years, range 23-53 years, with pathologically proved medulloblastomas. There were six (67%) with DM. The tumour was in the cerebellar hemisphere in eight patients (89%), including the three with CM, one of which was bilateral. All tumours were heterogeneous, giving predominantly low or isointense signal on T1- and isointense signal on T2-weighted images. Cystic or necrotic areas in all patients were particularly visible on T2-weighted images. Contrast enhancement was absent in one DM and varied from slight to intense in eight (three CM), homogeneous in one DM and patchy in seven. All tumours extended to the surface of the cerebellum and two had well-defined margins. MRI does not allow a clear distinction between DM and CM in adults. (orig.)

  11. MRI of rectal stromal tumour

    Dam, Claus; Lindebjerg, Jan; Rafaelsen, Søren Rafael

    2012-01-01

    to be aware of for the rectal multidisciplinary team. On suspicion of GIST, patients should be referred to a sarcoma centre. The diagnosis of rectal GIST can be suggested on MRI by the presence of a well-defined heterogeneously large mass with a necrotic center associated with a prominent extra...

  12. MRI of plants and foods

    As, van H.; Duynhoven, van J.P.M.

    2013-01-01

    The importance and prospects for MRI as applied to intact plants and to foods are presented in view of one of humanity's most pressing concerns, the sustainable and healthy feeding of a worldwide increasing population. Intact plants and foods have in common that their functionality is determined by

  13. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... very early stage by mapping the motion of water molecules in the tissue. This water motion, known as diffusion, is impaired by most ... the limitations of MRI of the Head? High-quality images are assured only if you are able ...

  14. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... E-mail: Area code: Phone no: Thank you! Images × Image Gallery Magnetic Resonance Imaging (MRI) procedure View full ... address): From (your name): Your e-mail address: Personal message (optional): Bees: Wax: Notice: RadiologyInfo respects your ...

  15. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... MRI. If you have a history of kidney disease or liver transplant, it will be necessary to perform a blood test to determine whether the kidneys are functioning adequately. Women should always inform their physician or technologist if ...

  16. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician ... Magnetic resonance imaging (MRI) is a noninvasive medical test that physicians use to diagnose and treat medical ...

  17. Infantile-onset saccade initiation delay (congenital ocular motor apraxia).

    Salman, Michael S

    2015-05-01

    Infantile-onset saccade initiation delay, also known as congenital ocular motor apraxia, typically presents in early infancy with horizontal head thrusts once head control is achieved. Defective initiation of horizontal saccades and saccade hypometria with normal saccadic velocity are characteristic findings. Isolated impairment of vertical saccades is rare. Impaired smooth ocular pursuit may be seen. Other relatively common features include developmental delay, hypotonia, ataxia, or clumsiness. Brain MRI may be normal or show a diverse range of abnormalities, most commonly involving the cerebellum. Defective slow phases of the optokinetic response are commonly associated with brain MRI abnormalities. Isolated defect of vertical saccade initiation may indicate supratentorial brain abnormalities on MRI. Joubert syndrome, a developmental midbrain-hindbrain malformation, and ataxia telangiectasia are both commonly associated with defective volitional and reflexive saccade initiation, saccade hypometria, and head thrusts. Both horizontal and vertical saccades are impaired in these two disorders.

  18. MRI diagnosis of bone marrow relapse in children with ALL

    Kan, J.H.; Hernanz-Schulman, Marta [Vanderbilt University, Department of Radiology and Radiological Sciences, Vanderbilt Children' s Hospital, Nashville, TN (United States); Frangoul, Haydar A. [Vanderbilt University, Department of Pediatric Hematology-Oncology, Vanderbilt Children' s Hospital, Nashville, TN (United States); Connolly, Susan A. [Harvard Medical School, Department of Radiology, Boston Children' s Hospital, Boston, MA (United States)

    2008-01-15

    Diffuse marrow replacement in acute leukemia is well known, but there are few reports describing the MRI features of pediatric leukemic relapse. Our purpose was to describe the MRI appearance of pediatric leukemic relapse. A total of 53 consecutive children with a history of ALL were referred for musculoskeletal MRI from 1 January 1998 to 28 February 2007 at one center, and from 1 January 2000 to 2 May 2007 at a second center. From this group, 14 children seen at initial diagnosis of leukemia and 2 children who underwent MRI after therapy for relapse were excluded. The remaining 37 children, 8 with relapse and 29 in remission, were studied. Images of patients with relapse and in remission were reviewed for type and configuration of marrow infiltration; coexisting marrow alterations including osteonecrosis or stress reaction were also reviewed. All eight children with relapse demonstrated nodular lesions with well-defined margins. Coexisting osteonecrosis was present in three children (38%) and pathologic fracture in one. Among the 29 children in remission, 9 showed stress reaction/fracture, 14 showed osteonecrosis and 9 showed ill-defined nodules, and in 5 the marrow was completely normal. Well-defined nodules in all patients with leukemic relapse suggest that this appearance is characteristic and distinct from the published findings of diffuse marrow replacement in acute leukemia. (orig.)

  19. Usefulness of Integrated PET/MRI in Head and Neck Cancer: A Preliminary Study

    Lee, Soo Jin; Seo, Hyo Jung; Cheon, Gi Jeong; Kim, Ji Hoon; Kim, E. Edmund; Kang, Keon Wook; Paeng, Jin Chul; Chung, Junekey; Lee, Dong Soo [Seoul National Univ., Seoul (Korea, Republic of)

    2014-06-15

    The new modality of an integrated positron emission tomography/magnetic resonance imaging (PET/MRI) has recently been introduced but not validated. Our objective was to evaluate clinical performance of {sup 18}F-fluoro-2-deoxyglucose ({sup 18}F-FDG) PET/MRI in patients with head and neck cancer. This retrospective study was conducted between January 2013 and February 2013. Ten patients (eight men, two women; mean age, 61.4±13.4 years) with histologically proven head and neck tumors were enrolled.Whole-body PET/MRI and regional positron emission tomography (PET) with dedicated MRI were sequentially obtained. Maximum standardized uptake value (SUVmax), SUVmean, metabolic tumor volume, total lesion glycolysis and contrast enhancement were analyzed. A total of ten whole-body positron emission tomography (PET), ten regional positron emission tomography (PET), ten dedicated MRI and ten regional PET/gadolinium-enhanced T1-weighted (Gd)-MRI images were analyzed for initial staging. Two nuclear medicine physicians analyzed positron emission tomography (PET) and PET/MRI with a consensus. One radiologist analyzed dedicated MRI. The primary lesions and number of metastatic lymph nodes analyzed from each image were compared. Eight patients were diagnosed with head and neck cancer (one tongue cancer, four tonsillar cancers, one nasopharyngeal cancer and two hypopharyngeal cancers) by histological diagnosis. Two benign tumors (pleomorphic adenoma and Warthin tumor) were diagnosed with surgical operation. Whole-body positron emission tomography (PET) and regional positron emission tomography (PET) attenuated by MRI showed good image quality for the lesion detection. Whole-body positron emission tomography (PET) and regional positron emission tomography (PET) detected ten primary sites and compensated for a missed lesion on dedicated MRI. A discordant number of suspicious lymph node metastases was noted according to the different images; 22, 16, 39 and 40 in the whole

  20. fMRI-BCI: a Review

    Da-Huan Li; Qin Gao; Wei-Shuai Lü; Hua-Fu Chen

    2009-01-01

    Functional magnetic resonance imaging (fMRI) is a new tool for brain-computer interface (BCI).This paper presents an overview to fMRI-BCI.Our attention is mainly put on the methods of signal acquisition,signal preprocessing,and signal analysis of basic fMRI-BCI structure.The available softwares and the applications of fMRI-BCI are briefly introduced.At last,we suggest focusing on some technologies to make fMRI-BCI more perfect.

  1. Advances in Clinical PET/MRI Instrumentation.

    Herzog, Hans; Lerche, Christoph

    2016-04-01

    In 2010, the first whole-body PET/MRI scanners installed for clinical use were the sequential Philips PET/MRI with PMT-based, TOF-capable technology and the integrated simultaneous Siemens PET/MRI. Avalanche photodiodes as non-magneto-sensitive readout electronics allowed PET integrated within the MRI. The experiences with these scanners showed that improvements of software aspects, such as attenuation correction, were necessary and that efficient protocols combining optimally PET and MRI must be still developed. In 2014, General Electric issued an integrated PET/MRI with SiPM-based PET detectors, allowing TOF-PET. Looking at the MRI components of current PET/MR imaging systems, primary improvements come from sequences and new coils.

  2. Initial Study

    Torp, Kristian

    2009-01-01

    Congestion is a major problem in most cities and the problem is growing (Quiroga, 2000) (Faghri & Hamad, 2002). When the congestion level is increased the drivers notice this as delays in the traffic (Taylor, Woolley, & Zito, 2000), i.e., the travel time for the individual driver is simply...... increased. In the initial study presented here, the time it takes to pass an intersection is studied in details. Two major signal-controlled four-way intersections in the center of the city Aalborg are studied in details to estimate the congestion levels in these intersections, based on the time it takes...

  3. High-temporospatial-resolution dynamic contrast-enhanced (DCE) wrist MRI with variable-density pseudo-random circular Cartesian undersampling (CIRCUS) acquisition: evaluation of perfusion in rheumatoid arthritis patients.

    Liu, Jing; Pedoia, Valentina; Heilmeier, Ursula; Ku, Eric; Su, Favian; Khanna, Sameer; Imboden, John; Graf, Jonathan; Link, Thomas; Li, Xiaojuan

    2016-01-01

    This study is to evaluate highly accelerated three-dimensional (3D) dynamic contrast-enhanced (DCE) wrist MRI for assessment of perfusion in rheumatoid arthritis (RA) patients. A pseudo-random variable-density undersampling strategy, circular Cartesian undersampling (CIRCUS), was combined with k-t SPARSE-SENSE reconstruction to achieve a highly accelerated 3D DCE wrist MRI. Two healthy volunteers and 10 RA patients were studied. Two patients were on methotrexate (MTX) only (Group I) and the other eight were treated with a combination therapy of MTX and anti-tumor necrosis factor (TNF) therapy (Group II). Patients were scanned at baseline and 3 month follow-up. DCE MR images were used to evaluate perfusion in synovitis and bone marrow edema pattern in the RA wrist joints. A series of perfusion parameters was derived and compared with clinical disease activity scores of 28 joints (DAS28). 3D DCE wrist MR images were obtained with a spatial resolution of 0.3 × 0.3 × 1.5 mm(3) and temporal resolution of 5 s (with an acceleration factor of 20). The derived perfusion parameters, most notably transition time (dT) of synovitis, showed significant negative correlations with DAS28-ESR (r = -0.80, p perfusion in RA joints, showing promise as a potential tool for evaluating treatment responses.

  4. Equilibrium disks, MRI mode excitation, and steady state turbulence in global accretion disk simulations

    Parkin, E R

    2012-01-01

    Global three dimensional magnetohydrodynamic (MHD) simulations of turbulent accretion disks are presented which start from fully equilibrium initial conditions in which the magnetic forces are accounted for and the induction equation is satisfied. The local linear theory of the magnetorotational instability (MRI) is used as a predictor of the growth of magnetic field perturbations in the global simulations. The linear growth estimates and global simulations diverge when non-linear motions - perhaps triggered by the onset of turbulence - upset the velocity perturbations used to excite the MRI. The saturated state is found to be independent of the initially excited MRI mode, showing that once the disk has expelled the initially net flux field and settled into quasi-periodic oscillations in the toroidal magnetic flux, the dynamo cycle regulates the global saturation stress level. Furthermore, time-averaged measures of converged turbulence, such as the ratio of magnetic energies, are found to be in agreement with...

  5. Integration of DCE-MRI and DW-MRI Quantitative Parameters for Breast Lesion Classification

    Roberta Fusco

    2015-01-01

    Full Text Available Objective. The purpose of our study was to evaluate the diagnostic value of an imaging protocol combining dynamic contrast-enhanced MRI (DCE-MRI and diffusion-weighted MRI (DW-MRI in patients with suspicious breast lesions. Materials and Methods. A total of 31 breast lesions (15 malignant and 16 benign proved by histological examination in 26 female patients were included in this study. For both DCE-MRI and DW-MRI model free and model based parameters were computed pixel by pixel on manually segmented ROIs. Statistical procedures included conventional linear analysis and more advanced techniques for classification of lesions in benign and malignant. Results. Our findings indicated no strong correlation between DCE-MRI and DW-MRI parameters. Results of classification analysis show that combining of DCE parameters or DW-MRI parameter, in comparison of single feature, does not yield a dramatic improvement of sensitivity and specificity of the two techniques alone. The best performance was obtained considering a full combination of all features. Moreover, the classification results combining all features are dominated by DCE-MRI features alone. Conclusion. The combination of DWI and DCE-MRI does not show a potential to dramatically increase the sensitivity and specificity of breast MRI. DCE-MRI alone gave the same performance as in combination with DW-MRI.

  6. Spinal cord involvement in chronic inflammatory demyelinating polyradiculoneuropathy: a clinical and MRI study.

    Ioannidis, Panagiotis; Parissis, Dimitris; Karapanayiotides, Theodoros; Maiovis, Pantelis; Karacostas, Dimitris; Grigoriadis, Nikolaos

    2015-06-01

    Concomitant central nervous system (CNS) involvement in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is rare. Although the spinal nerve roots may present MRI abnormalities in CIDP, hitherto, the spinal cord has been investigated in a single study. We retrospectively investigated clinically and with MRI a cohort of patients with definite CIDP diagnosis (EFNS/PNS criteria) for evidence of brain and spinal cord involvement, who were initially admitted in our department during the last 4 years. Among 12 patients with CIDP (men: 8, mean age: 59.3 years, mean disease duration: 3.8 years), nine patients had their MRI scan during a clinical relapse and three during remission. Brain MRI did not document typical multiple sclerosis lesions in any patient. We did not identify any MRI abnormalities in ten patients without clinical evidence of spinal cord involvement. Conversely, MRI disclosed extensive lesions of the thoracic cord in two patients with an overt spinal cord syndrome, whom we describe. This represents the biggest MRI study of CIDP patients who have been investigated for spinal cord involvement. Our data support earlier observations that a minority of CIDP patients may additionally develop CNS involvement of variable degree.

  7. [Simultaneous whole-body PET-MRI in pediatric oncology : More than just reducing radiation?].

    Gatidis, S; Gückel, B; la Fougère, C; Schmitt, J; Schäfer, J F

    2016-07-01

    Diagnostic imaging plays an essential role in pediatric oncology with regard to diagnosis, therapy-planning, and the follow-up of solid tumors. The current imaging standard in pediatric oncology includes a variety of radiological and nuclear medicine imaging modalities depending on the specific tumor entity. The introduction of combined simultaneous positron emission tomography (PET) and magnetic resonance imaging (MRI) has opened up new diagnostic options in pediatric oncology. This novel modality combines the excellent anatomical accuracy of MRI with the metabolic information of PET. In initial clinical studies, the technical feasibility and possible diagnostic advantages of combined PET-MRI have been in comparison with alternative imaging techniques. It was shown that a reduction in radiation exposure of up to 70 % is achievable compared with PET-CT. Furthermore, it has been shown that the number of imaging studies necessary can be markedly reduced using combined PET-MRI. Owing to its limited availability, combined PET-MRI is currently not used as a routine procedure. However, this new modality has the potential to become the imaging reference standard in pediatric oncology in the future. This review article summarizes the central aspects of pediatric oncological PET-MRI based on existing literature. Typical pediatric oncological PET-MRI cases are also presented.

  8. MRI findings of serous atrophy of bone marrow and associated complications

    Boutin, Robert D. [Department of Radiology, Sacramento, CA (United States); White, Lawrence M. [University of Toronto, Joint Department of Medical Imaging, Toronto General Hospital, Toronto, ON (Canada); Laor, Tal [Cincinnati Children' s Hospital Medical Center, Department of Radiology, Cincinnati, OH (United States); Spitz, Damon J. [New England Baptist Hospital, Department of Radiology, Boston, MA (United States); Lopez-Ben, Robert R. [Carolinas HealthCare System, Charlotte Radiology, Diagnostic Radiology, Charlotte, NC (United States); Stevens, Kathryn J. [Stanford University, Department of Radiology, Stanford, CA (United States); Bredella, Miriam A. [Massachusetts General Hospital and Harvard Medical School, Division of Musculoskeletal Imaging and Intervention, Department of Radiology, Boston, MA (United States)

    2015-09-15

    To report the MRI appearance of serous atrophy of bone marrow (SABM) and analyse clinical findings and complications of SABM. A retrospective search of MRI examinations of SABM was performed. Symptoms, underlying conditions, MRI findings, delay in diagnosis and associated complications were recorded. We identified 30 patients (15 male, 15 female; mean age: 46 ± 21 years) with MRI findings of SABM. Underlying conditions included anorexia nervosa (n = 10), cachexia from malignant (n = 5) and non-malignant (n = 7) causes, massive weight loss after bariatric surgery (n = 1), biliary atresia (n = 1), AIDS (n = 3), endocrine disorders (n = 2) and scurvy (n = 1). MRI showed mildly hypointense signal on T1- weighted and hyperintense signal on fat-suppressed fluid-sensitive images of affected bone marrow in all cases and similar signal abnormalities of the adjacent subcutaneous fat in 29/30 cases. Seven patients underwent repeat MRI due to initial misinterpretation of bone marrow signal as technical error. Superimposed fractures of the hips and lower extremities were common (n = 14). SABM occurs most commonly in anorexia nervosa and cachexia. MRI findings of SABM are often misinterpreted as technical error requiring unnecessary repeat imaging. SABM is frequently associated with fractures of the lower extremities. (orig.)

  9. IMAGING OF ROTATOR CUFF PATHOLOGY- IS ULTRASOUND AS GOOD AS MRI

    Vinot

    2015-12-01

    Full Text Available Aim of this study is to compare the diagnostic accuracy of ultrasound versus MRI in detecting rotator cuff pathology. Rotator cuff pathology involves group of disorder, which progresses from bursitis to tendinitis to partial tear and full thickenss tear. The most commonly affected tendon is the supraspinatus tendon. In our prospective study of 35 patients as initial ultrasound was followed by MRI sensitivity, specificity and accuracy for diagnosis of full thickness tear of supraspinatus when USG was compared to MRI was 100%, whereas sensitivity, specificity and accuracy of diagnosing partial thickness tear using ultrasound compared to MRI are 100%, 78% and 84%. There is no significant p value difference on comparing ultrasound with MRI on detecting tears. Ultrasound and MRI showed almost similar diagnostic accuracy in associated findings like tendon retraction, muscle atrophy, bursal effusion. Ultrasound also has additional value of dynamic evaluation, which is useful in evaluating subacromial and subcoracoid impingement. Modality choice for the evaluation of rotator cuff pathology should be based on several factors like availability, patient preference and clinical information being sought. The high resolution sonography is an attractive screening modality for rotator cuff in patients presenting with painful shoulder. A well performed ultrasound examination in most cases obviates the need for more invasive diagnostic tests like arthrography and cumbersome and expensive MRI examinations.

  10. EEG-fMRI integration for the study of human brain function.

    Jorge, João; van der Zwaag, Wietske; Figueiredo, Patrícia

    2014-11-15

    Electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) have proved to be extremely valuable tools for the non-invasive study of human brain function. Moreover, due to a notable degree of complementarity between the two modalities, the combination of EEG and fMRI data has been actively sought in the last two decades. Although initially focused on epilepsy, EEG-fMRI applications were rapidly extended to the study of healthy brain function, yielding new insights into its underlying mechanisms and pathways. Nevertheless, EEG and fMRI have markedly different spatial and temporal resolutions, and probe neuronal activity through distinct biophysical processes, many aspects of which are still poorly understood. The remarkable conceptual and methodological challenges associated with EEG-fMRI integration have motivated the development of a wide range of analysis approaches over the years, each relying on more or less restrictive assumptions, and aiming to shed further light on the mechanisms of brain function along with those of the EEG-fMRI coupling itself. Here, we present a review of the most relevant EEG-fMRI integration approaches yet proposed for the study of brain function, supported by a general overview of our current understanding of the biophysical mechanisms coupling the signals obtained from the two modalities.

  11. [Progress of clinical application of functional MRI in the localization of brain language area].

    Zhang, Nan; Lu, Junfeng; Wu, Jinsong

    2016-02-01

    For surgical operation in the functional area in the brain, it's commonly demanded to resect the lesion to the maximal extent on the basis of preserve the normal neural function, thus the precise localization of functional area is extremely important. As for the advantages of being widely available, easy to grasp and non-invasive, the functional MRI (fMRI) has come into wide use, while the application of language fMRI is still in the initial stage. It's important to choose appropriate fMRI task according to the individual condition of the subject, the commonly-adopted tasks include verb generation, picture naming, word recognition, word generation, etc. However, the effectiveness of using fMRI to localize language area is not totally satisfactory, adopting multiple task is an effective approach to improve the sensitivity of this technique. The application of resting state fMRI in the localization of language area and the further research of the role of fMRI in localizing the Chinese language area are the important future directions.

  12. MRI in subacute sclerosing panencephalitis

    Tuncay, R. [Department of Neurology, Istanbul Medical Faculty, University of Istanbul (Turkey); Akman-Demir, G. [Department of Neurology, Istanbul Medical Faculty, University of Istanbul (Turkey); Goekyigit, A. [Department of Neurology, Istanbul Medical Faculty, University of Istanbul (Turkey); Eraksoy, M. [Department of Neurology, Istanbul Medical Faculty, University of Istanbul (Turkey); Barlas, M. [Department of Neurology, Istanbul Medical Faculty, University of Istanbul (Turkey); Tolun, R. [Department of Neurology, Istanbul Medical Faculty, University of Istanbul (Turkey); Guersoy, G. [Department of Neurology, Istanbul Medical Faculty, University of Istanbul (Turkey)

    1996-10-01

    Subacute sclerosing panencephalitis (SSPE) is a progressive, slow virus infection of the brain, caused by the measles virus, attacking children and young adults. We investigated 15 patients with SSPE by MRI, with 5 normal and 10 pathological results. In the early period, lesions were in the grey matter and subcortical white matter. They were asymmetrical and had a predilection for the posterior parts of the hemispheres. Later, high-signal changes in deep white matter and severe cerebral atrophy were observed. Parenchymal lesions significantly correlated with the duration of disease. A significant relationship between MRI findings and clinical stage was observed in the 1st year of the disease. (orig.). With 4 figs., 1 tab.

  13. MRI of Wolfram syndrome (DIDMOAD)

    Galluzzi, P.; Filosomi, G.; Vallone, I.M.; Venturi, C. [Dept. of Neuroradiology, Policlinico ' ' Le Scotte' ' , Siena (Italy); Bardelli, A.M. [Dept. of Ophthalmological Sciences, Unit of Paediatric Ophthalmology, University of Siena (Italy)

    1999-10-01

    Wolfram syndrome (DIDMOAD) is a rare diffuse neurodegenerative disorder characterised by diabetes insipidus, diabetes mellitus, optic atrophy, deafness, and a wide variety of abnormalities of the central nervous system, urinary tract and endocrine glands. It may be familial or sporadic. Reported features on MRI of the brain are absence of the physiological high signal of the posterior lobe of the pituitary, shrinkage of optic nerves, chiasm and tracts, atrophy of the hypothalamic region, brain stem, cerebellum, and cerebral cortex. We report a 12-year-old girl with a 5-year history without brain stem, cerebellar or cerebral atrophy. MRI showed an unusual feature: a focus of high signal on PD- and T2-weighted images in the right substantia nigra. This is consistent with previously reported neuropathological post-mortem studies, but has never been reported in vivo. (orig.)

  14. MRI morphometry in Alzheimer's disease.

    Matsuda, Hiroshi

    2016-09-01

    MRI based evaluation of brain atrophy is regarded as a valid method to stage the disease and to assess progression in Alzheimer's disease (AD). Volumetric software programs have made it possible to quantify gray matter in the human brain in an automated fashion. At present, voxel based morphometry (VBM) is easily applicable to the routine clinical procedure with a short execution time. The importance of the VBM approach is that it is not biased to one particular structure and is able to assess anatomical differences throughout the brain. Stand-alone VBM software running on Windows, Voxel-based Specific Regional analysis system for AD (VSRAD), has been widely used in the clinical diagnosis of AD in Japan. On the other hand, recent application of graph theory to MRI has made it possible to analyze changes in structural connectivity in AD.

  15. The Added Diagnostic Value of Dynamic Contrast-Enhanced MRI at 3.0 T in Nonpalpable Breast Lesions

    Merckel, Laura G.; Verkooijen, Helena M.; Peters, Nicky H. G. M.; Mann, Ritse M.; Veldhuis, Wouter B.; Storm, Remmert K.; Weits, Teun; Duvivier, Katya M.; van Dalen, Thijs; Mali, Willem P. Th. M.; Peeters, Petra H. M.; van den Bosch, Maurice A. A. J.

    2014-01-01

    Objective To investigate the added diagnostic value of 3.0 Tesla breast MRI over conventional breast imaging in the diagnosis of in situ and invasive breast cancer and to explore the role of routine versus expert reading. Materials and Methods We evaluated MRI scans of patients with nonpalpable BI-RADS 3–5 lesions who underwent dynamic contrast-enhanced 3.0 Tesla breast MRI. Initially, MRI scans were read by radiologists in a routine clinical setting. All histologically confirmed index lesions were re-evaluated by two dedicated breast radiologists. Sensitivity and specificity for the three MRI readings were determined, and the diagnostic value of breast MRI in addition to conventional imaging was assessed. Interobserver reliability between the three readings was evaluated. Results MRI examinations of 207 patients were analyzed. Seventy-eight of 207 (37.7%) patients had a malignant lesion, of which 33 (42.3%) patients had pure DCIS and 45 (57.7%) invasive breast cancer. Sensitivity of breast MRI was 66.7% during routine, and 89.3% and 94.7% during expert reading. Specificity was 77.5% in the routine setting, and 61.0% and 33.3% during expert reading. In the routine setting, MRI provided additional diagnostic information over clinical information and conventional imaging, as the Area Under the ROC Curve increased from 0.76 to 0.81. Expert MRI reading was associated with a stronger improvement of the AUC to 0.87. Interobserver reliability between the three MRI readings was fair and moderate. Conclusions 3.0 T breast MRI of nonpalpable breast lesions is of added diagnostic value for the diagnosis of in situ and invasive breast cancer. PMID:24713637

  16. The added diagnostic value of dynamic contrast-enhanced MRI at 3.0 T in nonpalpable breast lesions.

    Laura G Merckel

    Full Text Available OBJECTIVE: To investigate the added diagnostic value of 3.0 Tesla breast MRI over conventional breast imaging in the diagnosis of in situ and invasive breast cancer and to explore the role of routine versus expert reading. MATERIALS AND METHODS: We evaluated MRI scans of patients with nonpalpable BI-RADS 3-5 lesions who underwent dynamic contrast-enhanced 3.0 Tesla breast MRI. Initially, MRI scans were read by radiologists in a routine clinical setting. All histologically confirmed index lesions were re-evaluated by two dedicated breast radiologists. Sensitivity and specificity for the three MRI readings were determined, and the diagnostic value of breast MRI in addition to conventional imaging was assessed. Interobserver reliability between the three readings was evaluated. RESULTS: MRI examinations of 207 patients were analyzed. Seventy-eight of 207 (37.7% patients had a malignant lesion, of which 33 (42.3% patients had pure DCIS and 45 (57.7% invasive breast cancer. Sensitivity of breast MRI was 66.7% during routine, and 89.3% and 94.7% during expert reading. Specificity was 77.5% in the routine setting, and 61.0% and 33.3% during expert reading. In the routine setting, MRI provided additional diagnostic information over clinical information and conventional imaging, as the Area Under the ROC Curve increased from 0.76 to 0.81. Expert MRI reading was associated with a stronger improvement of the AUC to 0.87. Interobserver reliability between the three MRI readings was fair and moderate. CONCLUSIONS: 3.0 T breast MRI of nonpalpable breast lesions is of added diagnostic value for the diagnosis of in situ and invasive breast cancer.

  17. MRI of vulvar Crohn disease

    Pai, Deepa; Dillman, Jonathan R.; Mahani, Maryam Ghadimi; Strouse, Peter J. [University of Michigan Health System, Department of Radiology, Section of Pediatric Radiology, C.S. Mott Children' s Hospital, F3503, Ann Arbor, MI (United States); Adler, Jeremy [University of Michigan Health System, Department of Pediatrics and Communicable Diseases, Division of Pediatric Gastroenterology, C. S. Mott Children' s Hospital, Ann Arbor, MI (United States)

    2011-04-15

    Crohn disease is a chronic granulomatous inflammatory disorder that most commonly affects the gastrointestinal tract, particularly the distal small bowel and colon. While certain extraintestinal manifestations of Crohn disease are relatively common and well-known, others, such as metastatic cutaneous involvement, are quite rare and may be difficult to recognize, particularly in the pediatric population. This case report illustrates the magnetic resonance imaging (MRI) appearance of vulvar region cutaneous Crohn disease in an 11-year-old girl. (orig.)

  18. MRI-induced retrocalcaneal bursitis

    Tol, J.L.; Dijk, C.N. van [Dept. of Orthopaedic Surgery, University of Amsterdam (Netherlands); Maas, M. [Dept. of Radiology, University of Amsterdam (Netherlands)

    1999-10-01

    This case report describes a patient with acute retrocalcaneal bursitis, which developed after MRI examination of the ankle. The sagittal T2*-weighted gradient echo sequence revealed an extensive susceptibility artifact in the area surrounding the Achilles tendon near its insertion at the os calcis. This artifact was caused by postsurgical metallic particles. We postulate that these particles were mechanically stimulated by the magnetic field and induced the inflammatory response. (orig.)

  19. MRI characteristics of midbrain tumours

    Sun, B. [Chinese Academy of Medical Science, Beijing (China). Neurosurgical Inst.]|[Department of Neuroradiology, Beijing Tiantan Hospital (China); Wang, C.C.; Wang, J. [Chinese Academy of Medical Science, Beijing (China). Neurosurgical Inst.

    1999-03-01

    We diagnosed 60 cases of midbrain tumours by MRI between 1993 to 1997. There were 39 males and 21 females, aged 2-64 years, mean 25.6 years. We found 38 patients with true intramedullary midbrain tumours, 11 predominantly in the tectum, 20 in the tegmentum and 7 with a downward extension to the pons; there were 7 within the cerebral aqueduct. There were 22 patients with infiltrating midbrain tumours extending from adjacent structures, 11 cases each from the thalamus and pineal region. All patients received surgical treatment. Gross total resection was achieved in 42 cases, subtotal (> 75 %) resection in 18. Pathological diagnoses included 16 low-grade and 15 high-grade astrocytomas; 5 oligodendroastrocytomas; 2 ependymomas; 11 glioblastomas; and 11 pineal parenchymal or germ-cell tumours. Midbrain tumours are a heterogeneous group of neoplasms, with wide variation in clinical and MRI features, related to the site and type of tumour. MRI not only allows precise analysis of their growth pattern, but also can lead to a correct preoperative diagnosis in the majority of cases. (orig.) (orig.) With 3 figs., 3 tabs., 19 refs.

  20. MRI findings of extramedullary haemopoiesis

    Chourmouzi, D.; Pistevou-Gompaki, K.; Plataniotis, G.; Skaragas, G.; Papadopoulos, L.; Drevelegas, A. [Dept. of Diagnostic Radiology and Radiation Oncology, AHEPA University Hospital, Thessaloniki (Greece)

    2001-09-01

    Extramedullary haemopoiesis (EH) is a compensatory process associated with chronic haemolytic anaemia. It is rare, however, for such an abnormality to cause spinal cord compression. We present two patients with known beta-thalassaemia intermedia who developed spinal cord compression due to masses of extramedullary haematopoietic tissue in the epidural space of the thoracic spine. The EH masses were diagnosed by MRI as an isointense epidural lesion on both T1- and T2-weighted images, compressing severely the spinal cord. After administration of a paramagnetic agent, an intermediate enhancement of the masses was evident. All the vertebral bodies had low to intermediate signal intensity as a result of displacement of fatty marrow by haematopoietic marrow. Expansion of thoracic ribs with bilateral paravertebral masses were characteristic. A small dose of radiotherapy was given and marked improvement in neurological symptoms was evident. An MRI examination established shrinkage of the mass and decompression of spinal cord. The role of MRI in diagnosis of EH masses is essential and radiation therapy is a very effective treatment for this rare complication. (orig.)

  1. MRI in insulinomas; Preliminary findings

    Liessi, Guido (Ospedale Civile, Castelfranco Veneto (Italy). Servizio di Radiologia); Pasquali, Claudio; Alfano D' Andrea, Alfonso; Pedrazzoli, Sergio (Padova Universita, I Cattedra di: Patologia Speciale Chirurgica (Italy). Istituto di Clinica Chirurgica); Scandellari, Cesare (Padova Universita, Cattedra di Medicina Interna V (Italy). Istituto di Semeiotica Medica)

    After establishing the diagnosis of an insulinoma, most surgeons prefer preoperative localization. Selective arteriography is usually considered the gold standard for this purpose. Recently, computed tomography (CT) and preoperative US have contended the role to angiography. MRI has been used in few cases of endocrine pancreatic tumors, and its role in this particular field has to be defined. Between November 1988-September 1990 7 adult patients who had undergone surgery were evaluated. Eight tumors were resected in 6 patients who were cured; in an 18-year-old woman surgical treatment was unsuccessful. Arterio-graphy, CT, preoperative US, MRI and intraoperative US detected 2, 6, 6, 5 and 6 tumors respectively. Two insulinomas (0.2 and 0.7 cm) were found at histologic examination in resected specimen. The ability of intra-operative US and careful surgical exploration to resolve more than 90 percent of cases makes the preoperative use of arteriography and CT questionable value. If further experience confirms these findings, US and MRI may suffice. (author). 13 refs.; 3 figs.; 1 tab.

  2. MRI after successful lumbar discectomy

    Goethem, J.W.M. van [Department of Radiology, University of Antwerp, Wilrijkstraat 10, B-2650 Edegem (Belgium); Kelft, E. van de [Department of Neurosurgery, University of Antwerp, Edegem (Belgium); Biltjes, I.G.G.M. [Department of Radiology, University of Antwerp, Wilrijkstraat 10, B-2650 Edegem (Belgium); Hasselt, B.A.A.M. van [Department of Radiology, University of Antwerp, Wilrijkstraat 10, B-2650 Edegem (Belgium); Hauwe, L. van den [Department of Radiology, University of Antwerp, Wilrijkstraat 10, B-2650 Edegem (Belgium); Parizel, P.M. [Department of Radiology, University of Antwerp, Wilrijkstraat 10, B-2650 Edegem (Belgium); Schepper, A.M.A. de [Department of Radiology, University of Antwerp, Wilrijkstraat 10, B-2650 Edegem (Belgium)

    1996-05-01

    Our aim was to establish the normal range of MRI findings after successful lumbar discectomy. We prospectively examined 34 consecutive patients with an excellent clinical outcome by MRI 6 weeks and 6 months after surgery. All examinations included sagittal and axial spin-echo (SE) T1-weighted images before and after intravenous gadolinium-DTPA and fast SE T2-weighted images. Contrast enhancement along the surgical tract was seen in all patients 6 weeks and 6 months after surgery. After 6 months minimal or no mass effect on the dural sac by epidural scar was seen. In 20 % of patients there was recurrent disc herniation, with mass effect. Enhancing nerve roots were seen in 20 % of patients 6 weeks postoperatively, and half of these were associated with recurrent disc herniation at the same side. None of these patients still showed nerve root enhancement 6 months after surgery. Postoperative MRI studies must be interpreted with great care since the features described in the failed back surgery syndrome are also found, to some extent, in asymptomatic postoperative patients. (orig.). With 7 figs., 2 tabs.

  3. Fetal MRI Characteristics of Exencephaly: A Case Report and Literature Review

    Ali Sharif

    2016-01-01

    Full Text Available We present the fetal MRI characteristics of exencephaly, a rare malformation of the cranium. The fetus was initially misdiagnosed as anencephaly at 14 weeks of estimated gestational age (EGA and later mislabeled as acrania at 20 weeks of EGA by ultrasound. A confirmatory magnetic resonance imaging (MRI at 29 weeks of EGA demonstrated findings consistent with exencephaly, which was confirmed after birth. To our knowledge, no full fetal MRI characteristics have been described. We hope to use this case to review the key MRI findings in differentiating exencephaly from other cranial vault defects and to help early diagnosis of exencephaly as the appropriate use of correct nomenclature allows better research while giving parents the most accurate and appropriate counseling.

  4. Current status and future role of brain PET/MRI in clinical and research settings

    Werner, P.; Barthel, H.; Sabri, O. [University Hospital Leipzig, Department of Nuclear Medicine, Leipzig (Germany); Drzezga, A. [University Hospital Cologne, Department of Nuclear Medicine, Koeln (Germany)

    2015-01-09

    Hybrid PET/MRI systematically offers a complementary combination of two modalities that has often proven itself superior to the single modality approach in the diagnostic work-up of many neurological and psychiatric diseases. Emerging PET tracers, technical advances in multiparametric MRI and obvious workflow advantages may lead to a significant improvement in the diagnosis of dementia disorders, neurooncological diseases, epilepsy and neurovascular diseases using PET/MRI. Moreover, simultaneous PET/MRI is well suited to complex studies of brain function in which fast fluctuations of brain signals (e.g. related to task processing or in response to pharmacological interventions) need to be monitored on multiple levels. Initial simultaneous studies have already demonstrated that these complementary measures of brain function can provide new insights into the functional and structural organization of the brain. (orig.)

  5. Slow-growing labyrinthine masses: contribution of MRI to diagnosis, follow-up and treatment

    Deux, J.F.; Marsot-Dupuch, K.; Tubiana, J.M. [Hopital Saint-Antoine, Paris (France). Service de Radiology; Ouayoun, M.; Meyer, B. [Service d`ORL, Hopital Saint-Antoine, 184 rue du Faubourg Saint-Antoine, F-75012 Paris (France); Tran Ba Huy, P. [Service d`ORL, Hopital Lariboisiere, 2 rue Ambroise Pare, F-75010 Paris (France); Sterkers, J.M.

    1998-10-01

    We report the use of MRI in the diagnosis, follow-up and therapeutic management of three cases of intralabyrinthine Schwannoma. The diagnosis was based on the history and initial and follow-up MRI findings. The main feature suggesting the diagnosis was a nodular intralabyrinthine mass of low signal intensity on T2-weighted images, and high or isointense signal on T1-weighted images (relative to cerebrospinal fluid), which showed contrast enhancement. Follow-up imaging showed growth of the tumour in one patient. One patient underwent surgery for severe tinnitus. To detect these lesions, MRI should be focussed on the inner ear, using thin-section T2-weighted and T1-weighted images before and after contrast medium. MRI allowed informed surgical planning. (orig.) (orig.) With 3 figs., 1 tab., 21 refs.

  6. Structural MRI of pediatric brain development: what have we learned and where are we going?

    Giedd, Jay N; Rapoport, Judith L

    2010-09-09

    Magnetic resonance imaging (MRI) allows unprecedented access to the anatomy and physiology of the developing brain without the use of ionizing radiation. Over the past two decades, thousands of brain MRI scans from healthy youth and those with neuropsychiatric illness have been acquired and analyzed with respect to diagnosis, sex, genetics, and/or psychological variables such as IQ. Initial reports comparing size differences of various brain components averaged across large age spans have given rise to longitudinal studies examining trajectories of development over time and evaluations of neural circuitry as opposed to structures in isolation. Although MRI is still not of routine diagnostic utility for evaluation of pediatric neuropsychiatric disorders, patterns of typical versus atypical development have emerged that may elucidate pathologic mechanisms and suggest targets for intervention. In this review we summarize general contributions of structural MRI to our understanding of neurodevelopment in health and illness.

  7. Importance of MRI in the diagnosis of vertebral involvement in generalized cystic lymphangiomatosis

    Renjen, Pooja; Kovanlikaya, Arzu; Brill, Paula W. [New York Presbyterian Hospital/Weill Cornell Medical Center, Department of Radiology, New York, NY (United States); Narula, Navneet [New York Presbyterian Hospital/Weill Cornell Medical Center, Department of Pathology, New York, NY (United States)

    2014-11-15

    A 9-year-old boy presented with the sudden onset of pleuritic chest pain and on CT was found to have a large pleural effusion, mediastinal fluid, splenic lesions and multiple apparently sclerotic vertebral bodies. Subsequent MRI showed that those vertebral bodies that appeared sclerotic were in fact normal, and the vertebral bodies initially interpreted as normal had an abnormal T1 and T2 hyperintense signal on MRI and were relatively lucent on CT. MRI also demonstrated abnormal heterogeneous T2 hyperintense paraspinal tissue and several multicystic soft tissue masses. Biopsy of two adjacent vertebral bodies, one relatively sclerotic and one lucent, demonstrated findings of bony remodeling without a specific diagnosis. Biopsy of an infiltrative mediastinal mass confirmed the diagnosis of generalized cystic lymphangiomatosis. MRI should be included in the assessment of vertebral involvement in this condition because CT and biopsy findings may be nonspecific. (orig.)

  8. Wireless Accelerometer for Neonatal MRI Motion Artifact Correction

    Martyn Paley

    2017-01-01

    Full Text Available A wireless accelerometer has been used in conjunction with a dedicated 3T neonatal MRI system installed on a Neonatal Intensive Care Unit to measure in-plane rotation which is a common problem with neonatal MRI. Rotational data has been acquired in real-time from phantoms simultaneously with MR images which shows that the wireless accelerometer can be used in close proximity to the MR system. No artifacts were observed on the MR images from the accelerometer or from the MR system on the accelerometer output. Initial attempts to correct the raw data using the measured rotational angles have been performed, but further work will be required to make a robust correction algorithm.

  9. Cardiac MRI-confirmed mesalamine-induced myocarditis.

    Baker, William L; Saulsberry, Whitney J; Elliott, Kaitlyn; Parker, Matthew W

    2015-09-04

    A 38-year-old Caucasian man with a medical history significant for inflammatory bowel disease (IBD) and mesalamine use presented to the emergency department with stabbing, pleuritic, substernal chest pain over the previous 2 days. Findings of leucocytosis, elevated cardiac enzymes and inflammatory markers, T-wave or ST-segment abnormalities and left ventricular systolic dysfunction suggested mesalamine-induced myocarditis. However, a cardiac MRI confirmed the diagnosis. Signs and symptoms improved within days of withdrawal of mesalamine, and initiation of corticosteroids and follow-up studies within the next year were unremarkable. Importantly, the diagnosis of mesalamine-induced myocarditis confirmed via cardiac MRI is a step rarely performed in published cases.

  10. MRI findings of juvenile psoriatic arthritis

    Lee, Edward Y.; Kleinman, Paul K. [Harvard Medical School, Department of Radiology, Boston, MA (United States); Children' s Hospital Boston, MA (United States); Sundel, Robert P.; Kim, Susan [Harvard Medical School, Rheumatology Program, Division of Immunology and the Department of Pediatrics, Boston, MA (United States); Children' s Hospital Boston, MA (United States); Zurakowski, David [Harvard Medical School, Department of Radiology, Boston, MA (United States); Harvard Medical School, Department of Orthopaedic Surgery, Boston, MA (United States); Children' s Hospital Boston, MA (United States)

    2008-11-15

    The aim of this study was to describe the magnetic resonance imaging (MRI) features of juvenile psoriatic arthritis (JpsA) in children in order to facilitate early diagnosis and proper management. Two pediatric radiologists retrospectively reviewed in consensus a total of 37 abnormal MRI examinations from 31 pediatric patients (nine boys, 22 girls; age range 1-17 years; mean age 9.4 years) who had a definite diagnosis of JpsA and underwent MRI. Each MRI was evaluated for synovium abnormality (thickening and enhancement), joint effusion (small, moderate, and large), bone marrow abnormality (edema, enhancement, and location of abnormality), soft tissue abnormality (edema, enhancement, atrophy, and fatty infiltration), tendon abnormality (thickening, edema, tendon sheath fluid, and enhancement), and articular abnormality (joint space narrowing and erosion). The distribution of abnormal MRI findings among the six categories for the 37 MRI examinations was evaluated. The number of abnormal MRI findings for each MRI examination was assessed. Age at MRI examination and all six categories of abnormal MRI findings according to gender were evaluated. There were a total 96 abnormal MRI findings noted on 37 abnormal MRI examinations from 31 pediatric patients. The 37 abnormal MRI examinations included MRI of the hand (n=8), knee (n = 8), ankle (n = 5), pelvis (n = 5), temporomandibular joint (n = 4), wrist (n = 3), foot (n = 2), elbow (n = 1), and shoulder (n = 1). Twenty-eight diffuse synovial thickening and/or enhancement were the most common MRI abnormality (29.2%). Joint effusion comprised 22 abnormal MRI findings (22.9%). There were 16 abnormal MRI bone marrow edema and/or enhancement findings (16.7%), and in seven (7.3%) the edema involved non-articular sites. Soft tissue abnormality manifested as edema and/or enhancement constituted 14 abnormal MRI findings (14.5%). There were ten MRI abnormalities (10.4%) involving tendons. Articular abnormality seen as joint space

  11. Bladder cancer: utility of MRI in detection of occult muscle-invasive disease

    Rosenkrantz, Andrew B. [Dept. of Radiology, NYU Langone Medical Center, New York (United States)], E-mail: Andrew.rosenkrantz@nyumc.org; Mussi, Thais C. [Dept. of Radiology, NYU Langone Medical Center, New York (United States); Hospital Israelita Albert Einstein, Sao Paulo (Brazil); Melamed, Jonathan [Dept. of Pathology, NYU Langone Medical Center, New York (United States); Taneja, Samir S.; Huang, William C. [Dept. of Urology, Div. of Urologic Oncology, NYU Langone Medical Center, New York (United States)

    2012-07-15

    Background. The presence of muscularis propria invasion by bladder cancer is a key factor in prognosis and treatment decisions, although may be missed by biopsy due to sampling error. MRI has shown potential for detection of muscle invasion but has not specifically been evaluated for this purpose in the setting of bladder cancer patients without evidence of muscle invasion on initial biopsy. Purpose. To evaluate the role of MRI in detection of muscularis propria invasion by bladder cancer following a pathologic diagnosis of non-invasive tumor. Material and Methods. This retrospective study included 23 patients who underwent pelvic MRI following a pathologic diagnosis of bladder cancer without muscularis propria invasion and in whom additional histologic evaluation was performed following MRI. Two radiologists in consensus reviewed T2-weighted images to identify those cases suspicious for muscle invasion on MRI. The radiologists identified whether cases suspicious for invasion demonstrated disruption of the T2-hypointense muscularis layer of the bladder wall, peri-vesical fat stranding, and peri-vesical soft tissue nodularity. Findings were compared with pathologic results obtained after MRI. Results. Suspicion was raised for muscle invasion in eight of 23 cases, four of which exhibited invasion on follow-up pathology. No case without suspicion on MRI exhibited invasion on follow-up pathology. Therefore, sensitivity and specificity were 100% and 79%, respectively. Among individual findings, muscularis disruption on T2WI exhibited sensitivity of 100% and specificity of 79%, peri-vesical fat stranding exhibited sensitivity and specificity of 50% and 84%, and peri-vesical soft tissue nodularity exhibited sensitivity and specificity of 25% and 100%. Conclusion. MRI demonstrated high sensitivity for detection of muscle invasion in cases of bladder cancer without invasion on initial histologic assessment. Muscularis disruption on T2WI appeared to exhibit a better

  12. Rapid MRI evaluation of acute intracranial hemorrhage in pediatric head trauma

    Ryan, Maura E.; Jaju, Alok [Northwestern University Feinberg School of Medicine, Department of Radiology, Chicago, IL (United States); Ann and Robert H. Lurie Children' s Hospital of Chicago, Department of Medical Imaging, Chicago, IL (United States); Ciolino, Jody D. [Northwestern University, Biostatistics Collaboration Center, Department of Preventive Medicine Feinberg School of Medicine, Chicago, IL (United States); Alden, Tord [Northwestern University Feinberg School of Medicine, Department of Neurological Surgery, Chicago, IL (United States); Ann and Robert H. Lurie Children' s Hospital of Chicago, Department of Neurosurgery, Chicago, IL (United States)

    2016-08-15

    Rapid MRI with ultrafast T2 sequences can be performed without sedation and is often used in place of computed tomography (CT) to evaluate pediatric patients for indications such as hydrocephalus. This study investigated the sensitivity of rapid magnetic resonance imaging (MRI) for detection and follow-up of acute intracranial hemorrhage in comparison to CT, which is commonly the first-line imaging. Patients presenting to a pediatric hospital with acute intracranial hemorrhage on CT and follow-up rapid MRI within 48 h were included. Rapid MRI studies consisted of three plane ultrafast T2 sequences either with or without axial gradient echo (GRE) sequences. Identification of hemorrhage on rapid MRI was assessed by readers both blinded and unblinded to prior CT results. One hundred two acute hemorrhages in 61 patients were identified by CT. Rapid MRI detection of subdural and epidural hemorrhages was modest in the absence of prior CT for comparison (sensitivity 61-74 %), but increased with review of the prior CT (sensitivity 80-86 %). Hemorrhage size was a significant predictor of detection (p < 0.0001). Three plane fast T2 images alone without GRE sequences were poor at detecting subarachnoid hemorrhage (sensitivity 10-25 %); rapid MRI with GRE sequences identified the majority of subarachnoid hemorrhage (sensitivity 71-93 %). GRE modestly increased detection of other extra-axial hemorrhages. Rapid MRI with GRE sequences is sensitive for most acute intracranial hemorrhages only when a prior CT is available for review. Rapid MRI is not adequate to replace CT in initial evaluation of intracranial hemorrhages but may be helpful in follow-up of known hemorrhages. (orig.)

  13. T2 weighted MRI for assessing renal lesions in transgenic mouse models of tuberous sclerosis

    Kalogerou, Maria; Zhang, Yadan; Yang, Jian; Garrahan, Nigel [Institute of Medical Genetics, School of Medicine, Cardiff University, Heath Park, Cardiff CF14 4XN (United Kingdom); Paisey, Stephen; Tokarczuk, Paweł; Stewart, Andrew [School of Bioscience, Cardiff University, Museum Avenue, Cardiff CF10 3AX (United Kingdom); Gallacher, John [Department of Primary Care and Public Health, School of Medicine, Cardiff University, Heath Park, Cardiff CF14 4YS (United Kingdom); Sampson, Julian R. [Institute of Medical Genetics, School of Medicine, Cardiff University, Heath Park, Cardiff CF14 4XN (United Kingdom); Shen, Ming Hong, E-mail: shenmh@cf.ac.uk [Institute of Medical Genetics, School of Medicine, Cardiff University, Heath Park, Cardiff CF14 4XN (United Kingdom)

    2012-09-15

    Objective: Transgenic mouse models of tuberous sclerosis (TSC) develop renal cysts, cystadenomas, solid adenomas and carcinomas. Identification and characterisation of these lesions in vivo may help in TSC pre-clinical trials. This study was to evaluate T2 weighted MRI for assessment of renal lesions in two Tsc mouse models. Materials and Methods: Tsc1{sup +/−}, Tsc2{sup +/−} and wild type mice were subjected to a first MRI scan at 12 months of age and a second scan 2 months later. One Tsc2{sup +/−} mouse was treated with rapamycin for two months after the initial scan. Immediately following the second scan, mice were sacrificed and MRI images were compared to renal histological findings. Results: MRI identified all types of Tsc-associated renal lesions in both Tsc1{sup +/−} and Tsc2{sup +/−} mice. The smallest detectable lesions were <0.1 mm{sup 3}. Eighty three percent of all renal lesions detected in the first scan were re-identified in the second scan. By MRI, these lesions demonstrated significant growth in the 9 untreated Tsc1{sup +/−} and Tsc2{sup +/−} mice but shrinkage in the rapamycin treated Tsc2{sup +/−} mouse. Between the two scans, MRI also revealed significant increase in both the total number and volume of lesions in untreated mice and decrease in the rapamycin treated mouse, respectively. In comparison to histological analysis MRI detected most cysts and cystadenomas (66%) but only a minority of solid tumours (29%). Conclusion: These results suggest that T2 weighted MRI may be a useful tool for assessing some renal lesions in pre-clinical studies using Tsc mouse models. However, improved sensitivity for T2 weighted MRI is required, particularly for solid renal lesions.

  14. MRI findings of cryptococcal infection on CNS: The long term follow-up: Case report

    Choi, Min Yun; Sol, Chang Ho; Kim, Byung Soo [Pusan National University College of Medicine, Pusan (Korea, Republic of); Jung, Chun Phil [Maryknoll Hospital, pusan (Korea, Republic of); Park, Beung Ho [Dong-a University College of Medicine, Pusan (Korea, Republic of)

    1993-07-15

    Authors presented the serial changes of brain MRI findings in two cases of cryptococcal meningitis. The MRI findings of the first patient (53 year old female) consisted of dilated Virchow-Robin spaces, leptomeningeal enhancement, cryptococcals and hydrocephalus. Dilated Virchow-Robin spaces were noted on the first MR obtained 33 days after symptom onset. The size and number of dilated Virchow-Robin space gradually decreased since 119 days after symptom onset (62 days after treatment). Faint leptomeningeal enhancement was found at cerebellar region on the first MRI, which became more distant and intense on the day 119, probably due to improper treatment. The leptomeningeal enhancement decreased on the days 156. Mild hydrocephalus was noted on MRI obtained 70 days after symptom onset, which markedly aggravated on the days 119. It decreased after steroid therapy alone. Enhancing cryptococcomas of variable size were noted at the right temporal lobe and cerebellum on MRI of the day 119, which decreased in size and number on the day 156. On the day 295 MRI showed nearly disappearance of the dilated Virchow-Robin space, but final leptomeningeal enhancement, cerebellar cryptococcomas and hydrocephalus still remained. The MRI findings of the second patient(36 year old female) showed the findings similar to those of the first patient. Initial MRI obtained 18 days after symptom onset showed no abnormal findings. Dilated Virchow-Robin spaces were noted on the day 36 (13 days after treatment onset), which nearly disappeared on the day 109. Enhancing cryptococcomas in both basal ganglia and cerebral cortex and leptomeningeal enhancement were noted on MRI of the day 136. Both cryptococcomas and leptomeningeal enhancement decreased in size and enhancing degree on the day 157. Hydrocephalus was noted on the day 109.

  15. [Is MRI monitoring useful in clinical practice in patients with multiple sclerosis? No].

    Edan, G

    2013-11-01

    Is regular MRI monitoring useful in clinical practice in multiple sclerosis patients treated with disease modifying therapy (DMT) drugs? My answer is no. Tacking a DMT drug is not by itself a pertinent criterion for requiring a systematic MRI monitoring in MS patients. Five clinical criteria should be taken into consideration before prescribing regular MRI examinations. The clinical form of the disease: MRI monitoring in DMT treated patients, has been demonstrated as useful only in pure relapsing-remitting MS patients. Up to now, there is no convincing demonstration of therapeutic efficacy with any DMT drug, neither first-line nor second-line drugs in patients with primary or secondary progressive MS disease. The duration of the disease, epidemiological data leading to the concept of a two-stage disability progression in MS, emphasizes the importance of treating as early as possible RRMS patients in order to stop accumulation of new focal MRI CNS lesions. In this regard, an annual monitoring for the 5 first years of the disease looks reasonable in order to better personalize the treatment choice among the few approved DMT drugs. The duration of the treatment: a first MRI assessment at month 6 after initiating a new DMT drug is adequate in order to better distinguish responder versus no responder. The persistence of Gado+lesions at 6 months is a strong indication for considering alternative treatment. The disease activity: both criteria, clinical and MRI, are needed to recognized very active or aggressive relapsing MS patients, leading to decide a rapid use of second-line treatment therapy. The treatment choice: in JC positive MS patients treated with natalizumab, the risk of PML is as high as more than 1 % in those JC+MS patients that are treated continuously more than 24 months. A regular MRI monitoring (3 or 6months) is recommended in order to detect as early as possible MRI abnormalities suggesting PML.

  16. Decision forests for learning prostate cancer probability maps from multiparametric MRI

    Ehrenberg, Henry R.; Cornfeld, Daniel; Nawaf, Cayce B.; Sprenkle, Preston C.; Duncan, James S.

    2016-03-01

    Objectives: Advances in multiparametric magnetic resonance imaging (mpMRI) and ultrasound/MRI fusion imaging offer a powerful alternative to the typical undirected approach to diagnosing prostate cancer. However, these methods require the time and expertise needed to interpret mpMRI image scenes. In this paper, a machine learning framework for automatically detecting and localizing cancerous lesions within the prostate is developed and evaluated. Methods: Two studies were performed to gather MRI and pathology data. The 12 patients in the first study underwent an MRI session to obtain structural, diffusion-weighted, and dynamic contrast enhanced image vol- umes of the prostate, and regions suspected of being cancerous from the MRI data were manually contoured by radiologists. Whole-mount slices of the prostate were obtained for the patients in the second study, in addition to structural and diffusion-weighted MRI data, for pathology verification. A 3-D feature set for voxel-wise appear- ance description combining intensity data, textural operators, and zonal approximations was generated. Voxels in a test set were classified as normal or cancer using a decision forest-based model initialized using Gaussian discriminant analysis. A leave-one-patient-out cross-validation scheme was used to assess the predictions against the expert manual segmentations confirmed as cancer by biopsy. Results: We achieved an area under the average receiver-operator characteristic curve of 0.923 for the first study, and visual assessment of the probability maps showed 21 out of 22 tumors were identified while a high level of specificity was maintained. In addition to evaluating the model against related approaches, the effects of the individual MRI parameter types were explored, and pathological verification using whole-mount slices from the second study was performed. Conclusions: The results of this paper show that the combination of mpMRI and machine learning is a powerful tool for

  17. Comparison of foetal US and MRI in the characterisation of congenital lung anomalies

    Alamo, Leonor, E-mail: leonor.alamo@chuv.ch [Unit of Pediatric Radiology, Department of Diagnostic and Interventional Radiology, Centre Hospitalière Universitaire Vaudois (CHUV), Rue du Bugnon 46, 1011 Lausanne (Switzerland); Reinberg, Olivier, E-mail: Olivier.reinberg@chuv.ch [Department of Pediatric Surgery, Centre Hospitalière Universitaire Vaudois (CHUV), Rue du Bugnon 46, 1011 Lausanne (Switzerland); Vial, Yvan, E-mail: Yvan.vial@chuv.ch [Unit of Prenatal Obstetric Diagnosis, Department of Gynecology and Obstetrics, Centre Hospitalière Universitaire Vaudois (CHUV), Rue du Bugnon 46, 1011 Lausanne (Switzerland); Gudinchet, François, E-mail: Francois.Gudinchet@chuv.ch [Unit of Pediatric Radiology, Department of Diagnostic and Interventional Radiology, Centre Hospitalière Universitaire Vaudois (CHUV), Rue du Bugnon 46, 1011 Lausanne (Switzerland); Meuli, Reto, E-mail: Reto.Meuli@chuv.ch [Unit of Pediatric Radiology, Department of Diagnostic and Interventional Radiology, Centre Hospitalière Universitaire Vaudois (CHUV), Rue du Bugnon 46, 1011 Lausanne (Switzerland)

    2013-12-01

    Objectives: To compare the accuracy of prenatal ultrasonography (US) to magnetic resonance imaging (MRI) in the characterisation of congenital lung anomalies, and to assess their agreement with final diagnosis. To evaluate the influence of additional MRI information on therapeutic management. Methods: 26 prenatal congenital lung anomalies detected consecutively between 2006 and 2012 were retrospectively evaluated. Lesions were initially observed at prenatal US and further investigated with MRI. Prenatal US and MRI imaging findings, and suggested diagnosis were compared with the final diagnosis, obtained from autopsies (4), pathological evaluation following surgical resection (15) and postnatal imaging studies (7). Results: Postnatal diagnoses included 7 congenital pulmonary airway malformations, 8 complex lesions, 7 overinflations, 1 sequestration, 1 bronchogenic cyst, 1 blastoma and 1 bilateral lymphangioma. Suggested prenatal US and MRI diagnosis was correct in 34.6% and 46.2% of patients, respectively, mainly isolated lung lesions with typical imaging findings. Nonspecific imaging findings at US and MRI studies were observed in 38.4% of cases. In 42% of the operated anomalies, pathological dissection revealed the presence of complex anomalies. MRI changed the US diagnosis, but not the further management in 9.7% of the lesions. Conclusions: Prenatal US and MRI showed a high accuracy in the diagnosis of isolated congenital lung lesions with typical imaging findings. However, overall characterisation rates were low, because of both a high percentage of complex lesions and of lesions with nonspecific imaging findings. MRI was better than US in characterising complex lesions, but its additional information did not influence therapy decisions.

  18. Openness initiative

    Duncan, S.S. [Los Alamos National Lab., NM (United States)

    1995-12-31

    Although antinuclear campaigns seem to be effective, public communication and education efforts on low-level radioactive waste have mixed results. Attempts at public information programs on low-level radioactive waste still focus on influencing public opinion. A question then is: {open_quotes}Is it preferable to have a program focus on public education that will empower individuals to make informed decisions rather than trying to influence them in their decisions?{close_quotes} To address this question, a case study with both quantitative and qualitative data will be used. The Ohio Low-Level Radioactive Waste Education Program has a goal to provide people with information they want/need to make their own decisions. The program initiated its efforts by conducting a statewide survey to determine information needed by people and where they turned for that information. This presentation reports data from the survey and then explores the program development process in which programs were designed and presented using the information. Pre and post data from the programs reveal attitude and knowledge shifts.

  19. The diagnostic utility of MRI in spondyloarthritis

    Pedersen, Susanne J; Weber, Ulrich; Østergaard, Mikkel

    2012-01-01

    The recently developed Assessment of SpondyloArthritis international Society (ASAS) classification criteria for axial and peripheral spondyloarthritis (SpA) are the first criteria ever to include findings on magnetic resonance imaging (MRI) of the sacroiliac joints. Features indicating sacroiliac...... joint inflammation on MRI are weighted equally to structural changes on conventional radiography, and thus MRI has become an important tool for use in daily practice to evaluate patients with clinically suspected early spondyloarthritis. However, MRI can also detect structural changes such as erosions...... and fat infiltrations, and recent studies suggest that assessment of both inflammatory and structural changes of the sacroiliac joints may improve the diagnostic utility of MRI. The present article reviews the evidence for the use of sacroiliac joint and spinal MRI to assess patients with axial...

  20. MRI in patients with low back pain

    Jensen, Rikke Krüger; Manniche, Claus; Leboeuf-Yde, Charlotte

    MRI in LBP patients: good or bad? Background: The routine use of radiology is presently discouraged in patients with low back pain (LBP). MRI provides clinicians and patients with detailed knowledge of the spinal structures and has no known physical side effects. It is possible that detailed...... insight into the pathological changes in LBP patients may affect the management of patients. However, this has never been tested. Until June 2006, all patients at our specialized public out-patient clinic, were referred to MRI on the basis of clinical indications, economic constraints, and availability...... of MRI (the "old" group). As a new approach, all patients with certain criteria are now referred to MRI before the clinical examination (the "new" group).   Objectives: The aims of this study were to investigate if the two different MRI approaches, the "old" and "new", resulted in differences in relation...

  1. Moyamoya disease: diagnostic accuracy of MRI.

    Yamada, I; Suzuki, S; Matsushima, Y

    1995-07-01

    Our purpose was to evaluate the diagnostic accuracy of MRI in moyamoya disease. We studied 30 patients with this disease, comparing MRI and angiographic findings. The diagnostic value of MRI was evaluated for occlusive lesions, collateral vessels, and parenchymal lesions. In all patients bilateral occlusion or stenosis of the supraclinoid internal carotid artery and proximal anterior and middle cerebral arteries was clearly shown by MRI, and staging of the extent of occlusion agreed with angiographic staging in 44 (73%) of 60 arteries. MRI, particularly coronal images, clearly showed basal cerebral moyamoya vessels in 54 hemispheres, and 45 of a total of 71 large leptomeningeal and transdural collateral vessels were identified. MRI also showed parenchymal lesions in 48 (80%) hemispheres, and the extent of occlusion in the anterior and posterior circulations respectively correlated with white matter and cortical and/or subcortical infarcts.

  2. Inexperienced clinicians can extract pathoanatomic information from MRI narrative reports with high reproducability for use in research/quality assurance

    Kent, Peter; Briggs, Andrew M; Albert, Hanne Birgit;

    2011-01-01

    Background Although reproducibility in reading MRI images amongst radiologists and clinicians has been studied previously, no studies have examined the reproducibility of inexperienced clinicians in extracting pathoanatomic information from magnetic resonance imaging (MRI) narrative reports...... pathoanatomic information from radiologist-generated MRI narrative reports. Methods Twenty MRI narrative reports were randomly extracted from an institutional database. A group of three physiotherapy students independently reviewed the reports and coded the presence of 14 common pathoanatomic findings using...... a categorical electronic coding matrix. Decision rules were developed after initial coding in an effort to resolve ambiguities in narrative reports. This process was repeated a further three times using separate samples of 20 MRI reports until no further ambiguities were identified (total n=80). Reproducibility...

  3. MRI of sequela of transverse myelitis

    Chen, W.C.; Lee, S.K.; Ho, Y.J. (Taichung Veterans General Hospital (Taiwan). Dept. of Radiology); Lee, K.R. (National Tsing-Hua Univ., Hsin-Chu (Taiwan). Inst. of Life Science); Mak, S.C.; Chi, C.S. (Taichung Veterans General Hospital (Taiwan). Dept. of Pediatrics)

    1992-09-01

    A 4-year-old boy developed acute paraplegia, associated with sensory impairement and bowel and urinary dysfunction after an URI. MRI showed diffuse hyperintensity in T2WI in the spinal cord below the T6 level. Acute transverse myelitis was diagnosed based on the clinical presentations and MRI findings. The patient had poor recovery and two months later, a follow-up MRI disclosed a severer diffuse atrophic change of the spinal cord in the affected segment. (orig.).

  4. fMRI-compatible rehabilitation hand device

    Tzika Aria; Astrakas Loukas; Weinberg Brian; Triantafyllou Christina; Muto Andrew; Khanicheh Azadeh; Mavroidis Constantinos

    2006-01-01

    Abstract Background Functional magnetic resonance imaging (fMRI) has been widely used in studying human brain functions and neurorehabilitation. In order to develop complex and well-controlled fMRI paradigms, interfaces that can precisely control and measure output force and kinematics of the movements in human subjects are needed. Optimized state-of-the-art fMRI methods, combined with magnetic resonance (MR) compatible robotic devices for rehabilitation, can assist therapists to quantify, mo...

  5. Navicular bone position determined by positional MRI

    Hansen, Philip; Johannsen, Finn E; Hangaard, Stine

    2016-01-01

    OBJECTIVE: To examine intraobserver, interobserver and between-day reproducibility of positional MRI for evaluation of navicular bone height (NVH) and medial navicular position (MNP). MATERIALS AND METHODS: Positional MRI (pMRI) of the foot was performed on ten healthy participants (0.25 T G......: Navicular height and medial navicular position can be measured by pMRI in a very reproducible manner within and between observers. Increased measurement variation is observed between-days in supine position, which may be due to small positional differences or other unknown biomechanical factors....

  6. Breast MRI in high risk patients

    Obdeijn, Inge-Marie

    2015-01-01

    markdownabstractAbstract In this thesis we address various indications of breast MRI, with the emphasis on the value of MRI in screening of women with high genetic risk for breast cancer, and especially in BRCA1 mutation carriers. We showed that in the era of up-to-date MRI expertise and digital mammography the screening efficacy is improved. However, the additional value of mammography over MRI is little while at the same time BRCA carriers are more sensitive the risks of low dose radiation ...

  7. MRI of central nervous system anomalies

    Izawa, M.; Oikawa, A.; Matoba, A.

    1987-05-01

    MRI was very useful in the evaluation of congenital anomalies of central nervous system as well as other nervous system disease with three-dimensional spatial resolution. We had experienced MRI of central nervous system anomalies, demonstrated characterisitic findings in each anomaly. MRI is useful to observe the coronal, horizontal and sagittal images of the brain and spinal cord in order to discuss the etiological mechanisms of spinal dysraphysm and its associated anomalies. In case of spina bifida cystica MRI was available to decide operative indication for radical operation and tetherd cord developed from postoperative scar or accompanied intraspinal lesions.

  8. Preoperative diagnosis of primary hyperparathyroidism by MRI

    Inouye, Takahiro; Tomita, Toshiki; Nitta, Seiichi [Tochigi Prefecture Saiseikai Utsunomiya Hospital (Japan); Kanou, Shigeru; Sato, Toshihiko

    1996-06-01

    We evaluated 12 patients with primary hyperparathyroidism by MRI. Nine patients presented parathyroid adenomas and the others hypertrophy of the parathyroid. Abnormal parathyroid was detected in 10 patients (83%) by T2-weighed image. And abnormal parathyroid was detected in one of the other two cases by MRI combined with {sup 99m}Tc{center_dot}MIBI-{sup 99m}Tc subtraction scintigraphy. Although we usually employ the axial view of MRI, it is incompatible with the operative field. We therefore hope that three-dimensional MRI will become compatible with the operative field in the future. (author)

  9. MRI of nasopharyngeal adenoid hypertrophy.

    Surov, Alexey; Ryl, Ina; Bartel-Friedrich, Sylvia; Wienke, Andreas; Kösling, Sabrina

    2016-10-01

    Nasopharyngeal adenoid hypertrophy (NAH) is a typical benign lesion. Due to involution, nasopharyngeal lymphatic tissue usually is not found in adults beyond the 30th to 40th year of life. However, occasionally NAH has been recognized after the 50th or 60th year. The aim of this study is to identify the frequency of NAH and to analyze its MRI findings in different age groups. From 2007 to 2011, 6693 MR investigations of the head were performed at our institution. MRI was obtained with a 1.5 T MRI device. NAH was identified in 18.0% of the patients. The frequency of NAH varied from 60.3% to 1.0% in the different age groups. The mean size of NAH was 23.2 ± 4.5 mm in cranio-caudal, 31.1 ± 5.2 mm in left-right, and 14.2 ± 4.1 mm in the anterior-posterior direction. The left-right and cranio-caudal sizes of NAH were largest in the 0-9 age group and decreased with age. On T1-w images most lesions (95.4%) were hypointense in comparison to the adjacent musculature. On T2-w fat-saturated images 82.4% of the lesions were hyperintense. After intravenous administration of contrast medium most lesions showed a slight enhancement (58.6%). Moderate enhancement was seen in 32.4% and a marked enhancement was identified in 9.0%. In the 0-9 age group most lesions showed a slight enhancement. Cysts within NAH were identified in 433 cases (35.9%). The frequency of cysts increased continuously with age, namely from 10.9% to 65.2%.

  10. Compressive myelopathy in fluorosis: MRI

    Gupta, R.K. [MR Section, Department of Radiology, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow-226014 (India); Agarwal, P. [MR Section, Department of Radiology, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow-226014 (India); Kumar, S. [MR Section, Department of Radiology, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow-226014 (India); Surana, P.K. [Department of Neurology, SGPGIMS, Lucknow-226014 (India); Lal, J.H. [MR Section, Department of Radiology, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow-226014 (India); Misra, U.K. [Department of Neurology, SGPGIMS, Lucknow-226014 (India)

    1996-05-01

    We examined four patients with fluorosis, presenting with compressive myelopathy, by MRI, using spin-echo and fast low-angle shot sequences. Cord compression due to ossification of the posterior longitudinal ligament (PLL) and ligamentum flavum (LF) was demonstrated in one and ossification of only the LF in one. Marrow signal was observed in the PLL and LF in all the patients on all pulse sequences. In patients with compressive myelopathy secondary to ossification of PLL and/or LF, fluorosis should be considered as a possible cause, especially in endemic regions. (orig.). With 2 figs., 1 tab.

  11. Imaging of posterior tibial tendon dysfunction—Comparison of high-resolution ultrasound and 3 T MRI

    Arnoldner, Michael A., E-mail: michael.arnoldner@meduniwien.ac.at [Medical University of Vienna, Vienna General Hospital, Department of Biomedical Imaging and Image-guided Therapy, Währinger Gürtel 18-20, 1090 Vienna (Austria); Gruber, Michael [Medical University of Vienna, Vienna General Hospital, Department of Biomedical Imaging and Image-guided Therapy, Währinger Gürtel 18-20, 1090 Vienna (Austria); Syré, Stefanie [Medical University of Vienna, Vienna General Hospital, Department of Trauma-Surgery, Währinger Gürtel 18-20, 1090 Vienna (Austria); Kristen, Karl-Heinz [Foot & Ankle Centre Vienna, Alser Straße 43/8, 1080 Vienna (Austria); Trnka, Hans-Jörg [Foot & Ankle Centre Vienna, Alser Straße 43/8, 1080 Vienna (Austria); Orthopaedic Hospital Vienna, Speisinger Straße 109, 1130 Vienna (Austria); Kainberger, Franz; Bodner, Gerd [Medical University of Vienna, Vienna General Hospital, Department of Biomedical Imaging and Image-guided Therapy, Währinger Gürtel 18-20, 1090 Vienna (Austria)

    2015-09-15

    Highlights: • 18 MHz high-resolution ultrasound appears to be slightly more accurate than 3 T MRI in the diagnosis of PTTD. • High-resolution ultrasound is recommended as an initial diagnostic tool. • Long-lasting PTT discomfort may require MRI. • Other pathologies can mimic PTTD. - Abstract: Purpose: Posterior tibial tendon dysfunction is the most common cause of acquired asymmetric flatfoot deformity. The purpose of this study was to determine and compare the diagnostic value of MRI and high-resolution ultrasound (HR-US) in posterior tibial tendon dysfunction (PTTD), and assess their correlation with intraoperative findings. Materials and methods: We reviewed 23 posterior tibial tendons in 23 patients with clinical findings of PTTD (13 females, 10 males; mean age, 50 years) with 18 MHz HR-US and 3 T MRI. Surgical intervention was performed in nine patients. Results: HR-US findings included 2 complete tears, 6 partial tears, 10 tendons with tendinosis, and 5 unremarkable tendons. MRI demonstrated 2 complete tears, 7 partial tears, 10 tendons with tendinosis, and 4 unremarkable tendons. HR-US and MRI were concordant in 20/23 cases (87%). Image findings for HR-US were confirmed in six of nine patients (66.7%) by intraoperative inspection, whereas imaging findings for MRI were concordant with five of nine cases (55.6%). Conclusion: Our results indicate that HR-US can be considered slightly more accurate than MRI in the detection of PTTD.

  12. Manually controlled steerable needle for MRI-guided percutaneous interventions.

    Henken, Kirsten R; Seevinck, Peter R; Dankelman, Jenny; van den Dobbelsteen, John J

    2017-02-01

    This study aims to develop and evaluate a manually controlled steerable needle that is compatible with and visible on MRI to facilitate full intra-procedural control and accurate navigation in percutaneous interventions. The steerable needle has a working channel that provides a lumen to a cutting stylet or a therapeutic instrument. A steering mechanism based on cable-operated compliant elements is integrated in the working channel. The needle can be steered by adjusting the orientation of the needle tip through manipulation of the handle. The steering mechanism is evaluated by recording needle deflection at constant steering angles. A steering angle of 20.3° results in a deflection of 9.1-13.3 mm in gelatin and 4.6-18.9 mm in porcine liver tissue at an insertion depth of 60 mm. Additionally, the possibility to control the needle path under MRI guidance is evaluated in a gelatin phantom. The needle can be steered to targets at different locations while starting from the same initial position and orientation under MRI guidance with generally available sequences. The steerable needle offers flexibility to the physician in control and choice of the needle path when navigating the needle toward the target position, which allows for optimization of individual treatment and may increase target accuracy.

  13. Central nervous system tuberculosis: MRI

    Kioumehr, F.; Dadsetan, M.R.; Rooholamini, S.A.; Au, A.

    1994-02-01

    The MRI findings of 18 proven cases of central nervous system (CNS) tuberculosis were reviewed; 10 patients were seropositive for HIV. All had medical, laboratory, or surgical proof of CNS tuberculosis. Eleven patients had meningitis, of whom two also had arachnoiditis. Five patients had focal intra-axial tuberculomas: four brain masses and one an intramedullary spinal lesion. Two patients had focal extra-axial tuberculomas: one in the pontine cistern, and one in the spine. In all 11 patients with meningitis MRI showed diffuse, thick, meningeal enhancement. All intraparenchymal tuberculomas showed low signal intensity on T2-weighted images and ring or nodular enhancement. The extra-axial tuberculomas had areas isointense or hypointense relative to normal brain and spinal cord on T2-weighted images. Although tuberculous meningitis cannot be differentiated from other meningitides on the basis of MR findings, intraparenchymal tuberculomas show characteristic T2 shortening, not found in most other space-occupying lesions. In the appropriate clinical setting, tuberculoma should be considered. (orig.)

  14. Physics of MRI: a primer.

    Plewes, Donald B; Kucharczyk, Walter

    2012-05-01

    This article is based on an introductory lecture given for the past many years during the "MR Physics and Techniques for Clinicians" course at the Annual Meeting of the ISMRM. This introduction is not intended to be a comprehensive overview of the field, as the subject of magnetic resonance imaging (MRI) physics is large and complex. Rather, it is intended to lay a conceptual foundation by which magnetic resonance image formation can be understood from an intuitive perspective. The presentation is nonmathematical, relying on simple models that take the reader progressively from the basic spin physics of nuclei, through descriptions of how the magnetic resonance signal is generated and detected in an MRI scanner, the foundations of nuclear magnetic resonance (NMR) relaxation, and a discussion of the Fourier transform and its relation to MR image formation. The article continues with a discussion of how magnetic field gradients are used to facilitate spatial encoding and concludes with a development of basic pulse sequences and the factors defining image contrast.

  15. Childhood moyamoya disease: hemodynamic MRI

    Tzika, A.A. [Department of Radiology, Children`s Hospital and Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115 (United States); Robertson, R.L. [Department of Radiology, Children`s Hospital and Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115 (United States); Barnes, P.D. [Department of Radiology, Children`s Hospital and Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115 (United States); Vajapeyam, S. [Department of Radiology, Children`s Hospital and Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115 (United States); Burrows, P.E. [Department of Radiology, Children`s Hospital and Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115 (United States); Treves, S.T. [Department of Radiology, Children`s Hospital and Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115 (United States); Scott, R.M. l [Department of Radiology, Children`s Hospital and Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115 (United States)

    1997-09-01

    Background. Childhood moyamoya disease is a rare progressive cerebrovascular disease. Objective. To evaluate cerebral hemodynamics using dynamic Gd-DTPA-enhanced imaging in children with moyamoya disease. Materials and methods. Eight children (2-11 years of age) with the clinical and angiographic findings typical of moyamoya disease, before and/or after surgical intervention (pial synangiosis), underwent conventional MR imaging (MRI) and hemodynamic MR imaging (HMRI). HMRI used a spoiled gradient-echo with low flip angle (10 deg) and long TE (TR/TE = 24/15 ms) to minimize T 1 effects and emphasize T 2{sup *} weighting. Raw and calculated hemodynamic images were reviewed. Three-dimensional time-of-flight MR angiography (MRA) and perfusion brain single photon emission computed tomography (SPECT) were also performed. Results. Abnormal hemodynamic maps resulting from vascular stenosis or occlusion and basal collaterals were observed in six patient studies. HMRI depicted perfusion dynamics of affected cerebrovascular territories, detected cortical perfusion deficits, and complemented conventional MRI and MRA. HMRI findings were consistent with those of catheter angiography and perfusion SPECT. Conclusion. Our preliminary experience suggests that HMRI may be of value in the preoperative and postoperative evaluation of surgical interventions in moyamoya disease. (orig.). With 4 figs., 3 tabs.

  16. Correlation of MRI Biomarkers with Tumor Necrosis in Hras5 Tumor Xenograft in Athymic Rats

    Daniel P. Bradley

    2007-05-01

    Full Text Available Magnetic resonance imaging (MRI can measure the effects of therapies targeting the tumor vasculature and has demonstrated that vascular-damaging agents (VDA induce acute vascular shutdown in tumors in human and animal models. However, at subtherapeutic doses, blood flow may recover before the induction of significant levels of necrosis. We present the relationship between changes in MRI biomarkers and tumor necrosis. Multiple MRI measurements were taken at 4.7 T in athymic rats (n = 24 bearing 1.94 ± 0.2-cm3 subcutaneous Hras5 tumors (ATCC 41000 before and 24 hours after clinically relevant doses of the VDA, ZD6126 (0-10 mg/kg, i.v.. We measured effective transverse relaxation rate (R2*, initial area under the gadolinium concentration-time curve (IAUGC60/150, equivalent enhancing fractions (EHF60/150, time constant (Ktrans, proportion of hypoperfused voxels as estimated from fit failures in Ktrans analysis, and signal intensity (SI in T2-weighted MRI (T2W. ZD6126 treatment induced < 90% dose-dependent tumor necrosis at 10 mg/kg; correspondingly, SI changes were evident from T2W MRI. Although R2* did not correlate, other MRI biomarkers significantly correlated with necrosis at doses of ≥ 5 mg/kg ZD6126. These data on Hras5 tumors suggest that the quantification of hypoperfused voxels might provide a useful biomarker of tumor necrosis.

  17. Neuroradiological findings in primary progressive aphasia: CT, MRI and cerebral perfusion SPECT

    Sinnatamby, R. [Dept. of Radiology, Addenbrooke`s Hospital NHS Trust, Cambridge (United Kingdom); Antoun, N.A. [Dept. of Radiology, Addenbrooke`s Hospital NHS Trust, Cambridge (United Kingdom); Freer, C.E.L. [Dept. of Radiology, Addenbrooke`s Hospital NHS Trust, Cambridge (United Kingdom); Miles, K.A. [Dept. of Nuclear Medicine, Addenbrooke`s Hospital NHS Trust, Cambridge (United Kingdom); Hodges, J.R. [Dept. of Neurology, Addenbrooke`s Hospital NHS Trust, Cambridge (United Kingdom)

    1996-04-01

    Primary progressive aphasia (PPA) is defined as progressive decline in language for 2 or more years with preservation of activities of daily living and general cognitive functions. Whereas the clinical features of this syndrome have been well documented, the neuroradiological findings have not been studied systematically. We studied 13 patients with PPA retrospectively: 10 underwent CT, 12 MRI and 12 cerebral perfusion studies using {sup 99m}Tc-HMPAO SPECT. CT and MR images were scored for focal atrophy by two independent assessors. Initial qualitative assessment of SPECT images was confirmed by quantitative analysis. CY was normal in 5 patients. Focal atrophy, affecting predominantly the left temporal lobe, was seen in 4 of 10 patients on CT, and 10 of 12 on MRI. Atrophy was localised primarily to the superior and middle temporal gyri on MRI. All 12 patients who underwent SPECT had unilateral temporal lobe perfusion defects, in 2 patients of whom MRI was normal. CT is relatively insensitive to focal abnormalities in PPA; MRI and SPECT are the imaging modalities of choice. MRI allows accurate, specific localisation of atrophy with the temporal neocortex. SPECT may reveal a functional decrease in cerebral perfusion prior to establishment of structural change. (orig.)

  18. Imaging of prostate cancer: a platform for 3D co-registration of in-vivo MRI ex-vivo MRI and pathology

    Orczyk, Clément; Mikheev, Artem; Rosenkrantz, Andrew; Melamed, Jonathan; Taneja, Samir S.; Rusinek, Henry

    2012-02-01

    Objectives: Multi-parametric MRI is emerging as a promising method for prostate cancer diagnosis. prognosis and treatment planning. However, the localization of in-vivo detected lesions and pathologic sites of cancer remains a significant challenge. To overcome this limitation we have developed and tested a system for co-registration of in-vivo MRI, ex-vivo MRI and histology. Materials and Methods: Three men diagnosed with localized prostate cancer (ages 54-72, PSA levels 5.1-7.7 ng/ml) were prospectively enrolled in this study. All patients underwent 3T multi-parametric MRI that included T2W, DCEMRI, and DWI prior to robotic-assisted prostatectomy. Ex-vivo multi-parametric MRI was performed on fresh prostate specimen. Excised prostates were then sliced at regular intervals and photographed both before and after fixation. Slices were perpendicular to the main axis of the posterior capsule, i.e., along the direction of the rectal wall. Guided by the location of the urethra, 2D digital images were assembled into 3D models. Cancer foci, extra-capsular extensions and zonal margins were delineated by the pathologist and included in 3D histology data. A locally-developed software was applied to register in-vivo, ex-vivo and histology using an over-determined set of anatomical landmarks placed in anterior fibro-muscular stroma, central. transition and peripheral zones. The mean root square distance across corresponding control points was used to assess co-registration error. Results: Two specimens were pT3a and one pT2b (negative margin) at pathology. The software successfully fused invivo MRI. ex-vivo MRI fresh specimen and histology using appropriate (rigid and affine) transformation models with mean square error of 1.59 mm. Coregistration accuracy was confirmed by multi-modality viewing using operator-guided variable transparency. Conclusion: The method enables successful co-registration of pre-operative MRI, ex-vivo MRI and pathology and it provides initial evidence

  19. Whole-body MRI of neuroblastoma

    Goo, Hyun Woo, E-mail: hwgoo@amc.seoul.k [Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Asanbyeongwon-gil 86, Songpa-gu, Seoul 138-736 (Korea, Republic of)

    2010-09-15

    Whole-body MRI (WBMRI) is an emerging imaging method that has a great potential in pediatric oncologic imaging. It appears useful in staging and monitoring neuroblastoma although its clinical impact has not been thoroughly evaluated. Among various imaging techniques currently available for WBMRI, coronal and sagittal STIR imaging with a quadrature body coil at 1.5T MR system is recommended for a standard protocol. Nevertheless, further technical improvements are anticipated at 3.0T MR system and multi-channel surface coil system. Scan time of WBMRI is reasonably short ranging from 20 min to 60 min. In localized neuroblatoma, WBMRI may help in predicting surgical risks by evaluating image-defined risk factors accurately. In addition, WBMRI is quite useful in detecting distant metastasis, assessing initial treatment responses, and identifying tumor recurrence of neuroblastoma. We should understand limitations of WBMRI in the evaluation of lymph node involvement, in the differentiation between viable tumor and non-viable residual lesion, and in the detection of calcified lesion. Diffusion-weighted imaging may improve diagnostic accuracy of WBMRI. Complementary use of WBMRI and other metabolic imaging method such as MIBG scintigraphy or PET probably increases diagnostic accuracy and, subsequently, improves clinical outcome of children with neuroblastoma.

  20. Demonstration of the reproducibility of free-breathing diffusion-weighted MRI and dynamic contrast enhanced MRI in children with solid tumours: a pilot study

    Miyazaki, Keiko; Jerome, Neil P.; Collins, David J.; Orton, Matthew R.; D' Arcy, James A.; Leach, Martin O. [Cancer Research UK Cancer Imaging Centre at The Institute of Cancer Research, London (United Kingdom); Wallace, Toni; Koh, Dow-Mu [Royal Marsden Hospital, Department of Radiology, London, England (United Kingdom); Moreno, Lucas [The Institute of Cancer Research, Paediatric Drug Development Team, Divisions of Cancer Therapeutics and Clinical Studies, London (United Kingdom); Spanish National Cancer Research Centre (CNIO), Clinical Research Programme, Madrid (Spain); The Royal Marsden NHS Foundation Trust, Paediatric Drug Development Unit, Children and Young People' s Unit, Sutton (United Kingdom); Pearson, Andrew D.J.; Marshall, Lynley V.; Carceller, Fernando; Zacharoulis, Stergios [The Institute of Cancer Research, Paediatric Drug Development Team, Divisions of Cancer Therapeutics and Clinical Studies, London (United Kingdom); The Royal Marsden NHS Foundation Trust, Paediatric Drug Development Unit, Children and Young People' s Unit, Sutton (United Kingdom)

    2015-09-15

    The objectives are to examine the reproducibility of functional MR imaging in children with solid tumours using quantitative parameters derived from diffusion-weighted (DW-) and dynamic contrast enhanced (DCE-) MRI. Patients under 16-years-of age with confirmed diagnosis of solid tumours (n = 17) underwent free-breathing DW-MRI and DCE-MRI on a 1.5 T system, repeated 24 hours later. DW-MRI (6 b-values, 0-1000 sec/mm{sup 2}) enabled monoexponential apparent diffusion coefficient estimation using all (ADC{sub 0-1000}) and only ≥100 sec/mm{sup 2} (ADC{sub 100-1000}) b-values. DCE-MRI was used to derive the transfer constant (K{sup trans}), the efflux constant (k{sub ep}), the extracellular extravascular volume (v{sub e}), and the plasma fraction (v{sub p}), using a study cohort arterial input function (AIF) and the extended Tofts model. Initial area under the gadolinium enhancement curve and pre-contrast T{sub 1} were also calculated. Percentage coefficients of variation (CV) of all parameters were calculated. The most reproducible cohort parameters were ADC{sub 100-1000} (CV = 3.26 %), pre-contrast T{sub 1} (CV = 6.21 %), and K{sup trans} (CV = 15.23 %). The ADC{sub 100-1000} was more reproducible than ADC{sub 0-1000}, especially extracranially (CV = 2.40 % vs. 2.78 %). The AIF (n = 9) derived from this paediatric population exhibited sharper and earlier first-pass and recirculation peaks compared with the literature's adult population average. Free-breathing functional imaging protocols including DW-MRI and DCE-MRI are well-tolerated in children aged 6 - 15 with good to moderate measurement reproducibility. (orig.)

  1. Anencephaly: MRI findings and pathogenetic theories.

    Calzolari, Ferdinando; Gambi, Beatrice; Garani, Giampaolo; Tamisari, Lalla

    2004-12-01

    We describe the MRI appearances of an anencephalic newborn who survived for 13 h; particularities of this case are male gender and the absence of other associated malformations. Moreover, we discuss the pathogenetic theories of anencephaly, correlating MRI findings with embryological data. An exencephaly-anencephaly sequence due to amnion rupture is hypothesized.

  2. Anencephaly: MRI findings and pathogenetic theories

    Calzolari, Ferdinando [Azienda Ospedaliera Universitaria, Department of Neuroradiology, Ferrara (Italy); Gambi, Beatrice [Ospedale S. Donato, Neonatal Unit, Arezzo (Italy); Garani, Giampaolo; Tamisari, Lalla [Universita degli Studi, Neonatal Unit, Ferrara (Italy)

    2004-12-01

    We describe the MRI appearances of an anencephalic newborn who survived for 13 h; particularities of this case are male gender and the absence of other associated malformations. Moreover, we discuss the pathogenetic theories of anencephaly, correlating MRI findings with embryological data. An exencephaly-anencephaly sequence due to amnion rupture is hypothesized. (orig.)

  3. MRI for clinically suspected appendicitis during pregnancy.

    Cobben, L.P.; Groot, I.; Haans, L.; Blickman, J.G.; Puylaert, J.

    2004-01-01

    OBJECTIVE: The purpose of this study was to evaluate whether MRI can be used to accurately diagnose or exclude appendicitis in pregnant patients with clinically suspected appendicitis. CONCLUSION: Our results suggest that MRI is helpful in the examination and diagnosis of acute appendicitis in pregn

  4. [Anatomic variants of Meckel's cave on MRI].

    Benoudiba, F; Hadj-Rabia, M; Iffenecker, C; Fuerxer, F; Bekkali, F; Francke, J P; Doyon, D

    1998-10-01

    Magnetic resonance imaging (MRI) gives an accurate analysis of Meckel's cave variability. Images were acquired in 50 patients with several sections for anatomical comparison. Using several sections, MRI is a suitable method for better analysis of the trigeminal cistern. The most frequent findings are symmetrical trigeminal cisterns. Expansion of Meckel's cave or its disappearance has pathological significance.

  5. MRI in acute phase of whiplash injury

    Fagerlund, M. [Dept. of Diagnostic Radiology, Univ. Hospital of Northern Sweden, Umeaa (Sweden); Bjoernebrink, J. [Dept. of Diagnostic Radiology, Univ. Hospital of Northern Sweden, Umeaa (Sweden); Pettersson, K. [Dept. of Orthopaedic Surgery, Univ. Hospital of Northern Sweden, Umeaa (Sweden); Hildingsson, C. [Dept. of Orthopaedic Surgery, Univ. Hospital of Northern Sweden, Umeaa (Sweden)

    1995-11-01

    A prospective MRI study of 39 whiplash patients was performed and the results were compared with the clinical findings within 15 days after trauma. The MRI parameters included disc bulging either with impingement on the anterior epidural space or with medullary compression, foraminal stenosis, dorsal ligament thickening, osteophyte extension and intramedullary or paravertebral soft tissue injury. All changes were graded visually on a four-point scale (no, some, moderate or extensive changes). After the MRI evaluation was made the clinical findings were analysed by two orthopaedic surgeons using a specially designed protocol. With MRI 29 patients (74 %) showed no or only slight changes, and were thus regarded as normal variations. Of these, 10 of 29 patients (34 %) had as the only symptom pain in the head or in the neck, 19 of 29 patients (66 %) showed neurological changes, either paresthesias, sensory deficits or weakness of upper extremities. In 10 (26 %) patients with moderate or extensive MRI changes, 3 of 10 (33 %) had only head or neck pain, or both, and 7 of 10 (66 %) had neurological changes. Use of MRI in whiplash injury is helpful, but it is not the first-choice radiological examination method. Despite neurological changes, the frequency of true traumatic lesions is low. There is no clear correlation between the patients` subjective symptoms or clinical signs and the findings with MRI. However, MRI can be used to find patients with disk herniation that can be treated surgically. (orig.)

  6. Cardiac MRI of the athlete's heart

    Prakken, N.H.J.

    2010-01-01

    The increase in pre-participation cardiovascular screening using the Lausanne protocol will ultimately lead to an increased use of cardiac MRI and MDCT in the cardiovascular work-up of athletes. The role of cardiac MRI is well established in the evaluation of cardiomyopathies, myocarditis, aortic st

  7. MRI study of lumbosacral lipoma in children

    Taviere, V.; Brunelle, F.; Baraton, J.; Teman, M.; Pierre-Kahn, A.; Lallemand, D.

    1989-06-01

    We report our experience with 16 cases of lumbosacral lipoma and MRI in children. From these observations, MRI appears to be a suitable examination. The exact situation of the cord and the lipoma is clearly seen. Associated anomalies such as syringomyelia is also clearly demonstrated.

  8. Paradigm shift in MRI for sciatica

    Barzouhi, Abdelilah el

    2013-01-01

    In contrast with the intuitive feeling of physicians many worrisome MRI findings do not correlate with patient outcome in patients with sciatica. Physicians should for example not automatically ascribe persistent or recurrent symptoms of sciatica to the presence of abnormalities visible on MRI. This

  9. Comparison of static MRI and pseudo-dynamic MRI in temporomandibular joint disorder patients

    Lee, Jin Ho; Yun, Kyoung In [Eulji Univ. School of Medicine, Seoul (Korea, Republic of); Park, In Woo; Choi, Hang Moon; Park, Moon Soo [Kangnung National Univ. College of Dentistry, Kangnung (Korea, Republic of)

    2006-12-15

    The purpose of this study was to elevate comparison of static MRI and pseudo-dynamic (cine) MRI in temporomandibular joint (TMJ) disorder patients. In this investigation, 33 patients with TMJ disorders were examined using both conventional static MRI and pseudo-dynamic MRI. Multiple spoiled gradient recalled acquisition in the steady state (SPGR) images were obtained when mouth opened and closed. Proton density weighted images were obtained at the closed and open mouth position in static MRI. Two oral and maxillofacial radiologists evaluated location of the articular disk, movement of condyle and bony change respectively and the posterior boundary of articular disk was obtained. No statistically significant difference was found in the observation of articular disk position, mandibular condylar movement and posterior boundary of articular disk using static MRI and pseudo-dynamic MRI (P>0.05). Statistically significant difference was noted in bony changes of condyle using static MRI and pseudo-dynamic MRI (P<0.05). This study showed that pseudo-dynamic MRI didn't make a difference in diagnosing internal derangement of TMJ in comparison with static MRI. But it was considered as an additional method to be supplemented in observing bony change.

  10. Abnormal MRI in acute optic neuritis and follow-up of patients with regard to multiple sclerosis

    Soltanzadeh A

    1997-09-01

    Full Text Available Twenty cases of isolated optic neuritis (15 female, 5 male were studied and followed for several months to years after the initial attack. The mean age of patients was 23 years (range: 15-29 years. The most frequent clinical manifestations were decreased visual acuity and blurred vision. A complete neurological examination was performed. In 15 cases (75% the initial brain MRI was abnormal. In fourteen cases, other signs of multiple sclerosis presented in one month to eight years following the initial attack of optic neuritis; eleven of the latter cases had an abnormal initial MRI. Acute optic neuritis can be considered a presenting feature of multiple sclerosis, particulary in the presence of an abnormal brain MRI.

  11. Prenatal diagnosis of horseshoe lung: contribution of MRI

    Tilea, Bogdana; Garel, Catherine; Sebag, Guy [Hopital Robert Debre, Department of Paediatric Imaging, Paris (France); Delezoide, Anne-Lise [Hopital Robert Debre, Department of Developmental Biology, Paris (France); Vuillard, Edith; Oury, Jean-Francois [Hopital Robert Debre, Department of Obstetrics and Gynaecology, Paris (France); Azancot, Annabelle [Hopital Robert Debre, Department of Fetal Cardiology, Paris (France)

    2005-10-01

    Horseshoe lung is a very rare pulmonary anomaly that is characterized by an isthmus of lung parenchyma bridging the right and left lungs and extending through the mediastinum. We report on the prenatal diagnosis of such a malformation in a 33-week-gestation fetus. The diagnosis was initially suspected on antenatal ultrasonography performed at 33 weeks and confirmed by fetal MRI and subsequent pathological examination after termination of pregnancy. To our knowledge, this is the first reported case of antenatal diagnosis of horseshoe lung. (orig.)

  12. Unexpected Coexisting Myocardial Infarction Detected by Delayed Enhancement MRI

    Edouard Gerbaud

    2009-01-01

    Full Text Available We report a case of an unexpected coexisting anterior myocardial infarction detected by delayed enhancement MRI in a 41-year-old man following a presentation with a first episode of chest pain during inferior acute myocardial infarction. This second necrotic area was not initially suspected because there were no ECG changes in the anterior leads and the left descending coronary artery did not present any significant stenoses on emergency coronary angiography. Unrecognised myocardial infarction may carry important prognostic implications. CMR is currently the best imaging technique to detect unexpected infarcts.

  13. Prospective motion correction for MRI using EEG-equipment

    Andersen, Mads; Madsen, Kristoffer Hougaard; Hanson, Lars G.

    2016-01-01

    A new prospective motion correction technique is presented that is based on signals from gradient switching, in an EEG-cap with interconnected electrodes the subject wears during scanning. The method has no line-of-sight limitations as optical methods, requires no interleaved navigator modules or...... or additional hardware for sites already doing EEG-fMRI. Instead a training scan is performed were signals recorded with the EEG-system are correlated with motion parameters estimated by image realignment. Initial results from application of the method in a phantom are promising....

  14. Pathologic Findings in MRI-Guided Needle Core Biopsies of the Breast in Patients with Newly Diagnosed Breast Cancer

    Siziopikou, K. P.; P. Jokich; Cobleigh, M.

    2011-01-01

    The role of MRI in the management of breast carcinoma is rapidly evolving from its initial use for specific indications only to a more widespread use on all women with newly diagnosed early stage breast cancer. However, there are many concerns that such widespread use is premature since detailed correlation of MRI findings with the underlying histopathology of the breast lesions is still evolving and clear evidence for improvements in management and overall prognosis of breast cancer patients...

  15. MRI findings in 100 epileptic children

    Suzukawa, Junko; Sugimoto, Tateo; Araki, Atsushi (Kansai Medical School, Moriguchi, Osaka (Japan)) (and others)

    1993-02-01

    Findings of magnetic resonance imaging (MRI) of the brain were retrospectively reviewed in 100 consecutive pediatric patients with epilepsy in relation to the type of epilepsy and prognosis. There were 65 boys and 35 girls, ranging in age from 3 months to 25 years. Among 100 patients, 67 (a total of 102 lesions) showed abnormal findings on MRI. Morphological abnormalities, including ventricular enlargement, atrophy and malformation, were seen in 54 patients. Periventricular (n=14), frontal (n=3), temporal (n=8) and occipital (n=7) areas were of high signal intensity on T2-weighted images. According to the type of epilepsy, MRI abnormality was seen in 34 (61%) of 56 patients with partial seizures and 33 (76%) of 44 patients with generalized seizures. When associated with cerebral palsy and mental retardation, the incidence of MRI abnormality was high. There was no sigificant correlation between MRI findings and prognosis. (N.K.).

  16. MRI and pathology in persistent postherniotomy pain

    Aasvang, Eske Kvanner; Jensen, Karl-Erik; Fiirgaard, Bente

    2009-01-01

    BACKGROUND: Persistent postherniotomy pain impairs everyday life in 5% to 10% of patients. MRI can potentially be useful in the investigation of pathogenic mechanisms and guide surgeons in mesh removal and neurectomy. No study has investigated interobserver agreement or MRI-specific findings...... in persistent postherniotomy pain. STUDY DESIGN: Thirty-two patients with persistent postherniotomy pain > 1 year after uni- or bilateral groin hernia repair and 6 pain-free postherniotomy controls were MRI scanned, resulting in a total of 32 painful groins, 15 pain-free operated groins, and 29 pain......-free unoperated groins scanned. Two blinded observers separately assessed groins using a predefined list of possible MRI pathology and anatomic landmarks. Primary outcomes included interobserver agreement assessed by calculating kappa-coefficients. Secondary outcomes included frequency of MRI pathology in painful...

  17. MRI and CT patterns of neurocysticercosis

    Rodiek, S.O.; Rupp, N.; Einsiedel, H. von

    1987-05-01

    MRI and CT manifestations were studied in five cases of neurocysticercosis. As demonstrated by long-term follow-ups the disease usually causes multiple lesions the morphology of which depends on the life cycle of the parasite. Tissue lesions consist of three main types: 1) vital cysticerci, 2) inflammatory parenchymatous reactions following degenerating cysts and 3) calcified granulomas. MRI provides all information that is given by CT except for small calcifications which are usually missed. Morphological details of vital cysticerci like cysts wall and scolex are better outlined by MRI. When i.v. contrast medium is applied, it leads to nodular or annular enhancement of inflamed tissue. The sensitivity of MRI towards edema caused by parasite exceeds that of CT by several weeks. CT and MRI are complementary methods providing at the present time the highest degree of specificity in diagnosing neurocysticercosis.

  18. fMRI. Basics and clinical applications

    Ulmer, Stephan; Jansen, Olav (eds.) [University Hospital of Schleswig-Holstein, Kiel (Germany). Inst. of Neuroradiology, Neurocenter

    2010-07-01

    Functional MRI (fMRI) and the basic method of BOLD imaging were introduced in 1993 by Seiji Ogawa. From very basic experiments, fMRI has evolved into a clinical application for daily routine brain imaging. There have been various improvements in both the imaging technique as such as well as in the statistical analysis. In this volume, experts in the field share their knowledge and point out possible technical barriers and problems explaining how to solve them. Starting from the very basics on the origin of the BOLD signal, the book covers technical issues, anatomical landmarks, presurgical applications, and special issues in various clinical fields. Other modalities for brain mapping such as PET, TMS, and MEG are also compared with fMRI. This book is intended to give a state-of-the-art overview and to serve as a reference and guide for clinical applications of fMRI. (orig.)

  19. Clinical functional MRI. Presurgical functional neuroimaging

    Stippich, C. (ed.) [Heidelberg Univ. (Germany). Div. of Neuroradiology

    2007-07-01

    Functional magnetic resonance imaging (fMRI) permits noninvasive imaging of the ''human brain at work'' under physiological conditions. This is the first textbook on clinical fMRI. It is devoted to preoperative fMRI in patients with brain tumors and epilepsies, which are the most well-established clinical applications. By localizing and lateralizing specific brain functions, as well as epileptogenic zones, fMRI facilitates the selection of a safe treatment and the planning and performance of function-preserving neurosurgery. State of the art fMRI procedures are presented, with detailed consideration of the physiological and methodological background, imaging and data processing, normal and pathological findings, diagnostic possibilities and limitations, and other related techniques. All chapters are written by recognized experts in their fields, and the book is designed to be of value to beginners, trained clinicians and experts alike. (orig.)

  20. NMR, MRI, and spectroscopic MRI in inhomogeneous fields

    Demas, Vasiliki; Pines, Alexander; Martin, Rachel W; Franck, John; Reimer, Jeffrey A

    2013-12-24

    A method for locally creating effectively homogeneous or "clean" magnetic field gradients (of high uniformity) for imaging (with NMR, MRI, or spectroscopic MRI) both in in-situ and ex-situ systems with high degrees of inhomogeneous field strength. THe method of imaging comprises: a) providing a functional approximation of an inhomogeneous static magnetic field strength B.sub.0({right arrow over (r)}) at a spatial position {right arrow over (r)}; b) providing a temporal functional approximation of {right arrow over (G)}.sub.shim(t) with i basis functions and j variables for each basis function, resulting in v.sub.ij variables; c) providing a measured value .OMEGA., which is an temporally accumulated dephasing due to the inhomogeneities of B.sub.0({right arrow over(r)}); and d) minimizing a difference in the local dephasing angle .phi.({right arrow over (r)},t)=.gamma..intg..sub.0.sup.t{square root over (|{right arrow over (B)}.sub.1({right arrow over (r)},t')|.sup.2+({right arrow over (r)}{right arrow over (G)}.sub.shimG.sub.shim(t')+.parallel.{right arrow over (B)}.sub.0({right arrow over (r)}).parallel..DELTA..omega.({right arrow over (r)},t'/.gamma/).sup.2)}dt'-.OMEGA. by varying the v.sub.ij variables to form a set of minimized v.sub.ij variables. The method requires calibration of the static fields prior to minimization, but may thereafter be implemented without such calibration, may be used in open or closed systems, and potentially portable systems.

  1. Long-term MRI findings of patients with embolized cerebral aneurysms

    Pyysalo, Liisa M.; Niskakangas, Tero T.; Oehman, Juha E. (Tampere Univ. Hospital, Dept. of Neurosurgery, Tampere (Finland)), email: liisa.pyysalo@uta.fi; Keski-Nisula, Leo H.; Kaehaerae, Veikko J. (Medical Imaging Center, Tampere (Finland))

    2011-02-15

    Background: Long-term follow-up studies after endovascular treatment for intracranial aneurysm are still rare and inconclusive. Parenchymal infarctions related to aneurysms have mostly been studied in patients with subarachnoidal hemorrhage (SAH) but infarction rates in patients with endovascularly treated unruptured aneurysms have been little studied. Purpose: To determine the frequency of permanent parenchymal lesions as detected in magnetic resonance imaging (MRI) in patients treated with endovascular coiling and to assess aneurysm-related infarctions after the initial treatment period. Material and Methods: A total of 64 patients (32 with primarily ruptured aneurysms) with 69 embolized aneurysms were examined neurologically and by MRI and magnetic resonance angiography (MRA) more than 9 years after the initial endovascular treatment. Results: A total of 14 out of 32 (44%) SAH patients and 11 (34%) patients with unruptured aneurysms had parenchymal lesions in MRI. Infarctions were detected in 10 (31%) SAH patients and the majority (9/10, 90%) of them were aneurysm-related. All aneurysm-related infarctions were detected at the acute hospitalization stage. A total of six (55%) out of 11 infarctions in patients with unruptured aneurysms were aneurysm-related and two of them appeared after the treatment period. Patients with infarction had poorer clinical outcome than patients with no ischemic lesions in MRI. Conclusion: Nineteen percent of patients with unruptured and 41% with ruptured aneurysms had aneurysmrelated parenchymal lesions in MRI. Most of these were detected during acute treatment period. Aneurysmrelated infarctions after treatment period are uncommon

  2. MRI evaluation of aseptic osteonecrosis in children over the course of hyperbaric oxygen therapy

    Scherer, A.; Engelbrecht, V.; May, P.; Moedder, U. [Duesseldorf Univ. (Germany). Inst. fuer Diagnostische Radiologie; Bernbeck, B.; Goebel, U. [Duesseldorf Univ. (Germany). Dept. of Pediatric Hematology and Oncology; Willers, R. [Duesseldorf Univ. (Germany). Inst. of Statistics

    2000-10-01

    Purpose: The study aimed at MRI evaluation of aseptic osteonecrosis (AON) in children over the course of hyperbaric oxygen (HBO) therapy. Material and methods: Retrospective analysis of 72 MRI studies in 20 children presenting with AON during chemotherapy. Two groups were differentiated: Gr. I (n=8) was treated exclusively with relief of weightbearing structures, Gr. II (n=12) was additionally treated with HBO therapy. The MRI examinations were evaluated by a point-score system (1-6 points) by two radiologists. Results: Gr. II initially showed more severe findings (average score: 3.4) in comparison to Gr. I (average score: 2.65). During the follow-up time period the average scores rose to 3.2 score-points in Gr. I and 4.1 points in Gr. II. No statistically significant difference was evident between the two groups in the course of AON. Conclusion: The majority of chemotherapy associated AON which initially present with advanced findings show a progression in MRI over their further course. HBO therapy in addition to the relief of affected weightbearing structures statistically shows no significant improvement in MRI morphology during the course of the treatment. (orig.)

  3. MRI-conditional pacemakers: current perspectives

    Ferreira AM

    2014-05-01

    Full Text Available António M Ferreira,1,2 Francisco Costa,2 António Tralhão,2 Hugo Marques,3 Nuno Cardim,1 Pedro Adragão1,2 1Cardiology Department, Hospital da Luz, 2Cardiology Department, Hospital Santa Cruz- CHLO, 3Radiology Department, Hospital da Luz, Lisbon, Portugal Abstract: Use of both magnetic resonance imaging (MRI and pacing devices has undergone remarkable growth in recent years, and it is estimated that the majority of patients with pacemakers will need an MRI during their lifetime. These investigations will generally be denied due to the potentially dangerous interactions between cardiac devices and the magnetic fields and radiofrequency energy used in MRI. Despite the increasing reports of uneventful scanning in selected patients with conventional pacemakers under close surveillance, MRI is still contraindicated in those circumstances and cannot be considered a routine procedure. These limitations prompted a series of modifications in generator and lead engineering, designed to minimize interactions that could compromise device function and patient safety. The resulting MRI-conditional pacemakers were first introduced in 2008 and the clinical experience gathered so far supports their safety in the MRI environment if certain conditions are fulfilled. With this technology, new questions and controversies arise regarding patient selection, clinical impact, and cost-effectiveness. In this review, we discuss the potential risks of MRI in patients with electronic cardiac devices and present updated information regarding the features of MRI-conditional pacemakers and the clinical experience with currently available models. Finally, we provide some guidance on how to scan patients who have these devices and discuss future directions in the field. Keywords: pacemakers, magnetic resonance imaging, MRI, MRI-conditional devices, safety

  4. 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

    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.

  5. Combined PET/MRI scanner

    Schlyer, David; Woody, Craig L.; Rooney, William; Vaska, Paul; Stoll, Sean; Pratte, Jean-Francois; O'Connor, Paul

    2007-10-23

    A combined PET/MRI scanner generally includes a magnet for producing a magnetic field suitable for magnetic resonance imaging, a radiofrequency (RF) coil disposed within the magnetic field produced by the magnet and a ring tomograph disposed within the magnetic field produced by the magnet. The ring tomograph includes a scintillator layer for outputting at least one photon in response to an annihilation event, a detection array coupled to the scintillator layer for detecting the at least one photon outputted by the scintillator layer and for outputting a detection signal in response to the detected photon and a front-end electronic array coupled to the detection array for receiving the detection signal, wherein the front-end array has a preamplifier and a shaper network for conditioning the detection signal.

  6. Fetal MRI of clubfoot associated with myelomeningocele

    Servaes, Sabah; Hernandez, Andrea; Gonzalez, Leonardo; Victoria, Teresa; Jaramillo, Diego; Christopher Edgar, J.; Johnson, Ann [Children' s Hospital of Philadelphia, Department of Radiology, Philadelphia, PA (United States); Johnson, Mark [Children' s Hospital of Philadelphia, Department of Fetal Surgery, Philadelphia, PA (United States)

    2010-12-15

    The sensitivity and specificity of evaluating clubfoot deformity by MR in high-risk fetuses is currently unknown. To correlate fetal MRI with US in the assessment of clubfoot and to identify the MRI features most characteristic of clubfoot. With IRB approval and informed consent, the presence of fetal clubfoot was prospectively evaluated in mothers referred for MRI for a fetus with myelomeningocele. Two radiologists blind to the US results independently reviewed the MRI for the presence of clubfoot. MRI results were compared with US results obtained the same day and birth outcomes. Of 20 patients enrolled, there were 13 clubfeet. Interobserver agreement for the presence of clubfoot was 100%. The sensitivity of the MRI exam was 100% and the specificity 85.2%. A dedicated sagittal imaging plane through the ankle region allowed the most confident diagnosis; medial deviation of the foot relative to the leg was seen in all 13 fetuses with clubfoot. The correlation of fetal MRI with US in the evaluation of clubfoot yields a sensitivity of 100% and specificity of 85.2%. The sagittal plane provided the most useful information. (orig.)

  7. Lung MRI for experimental drug research

    Beckmann, Nicolau [Discovery Technologies, Novartis Institutes for BioMedical Research, Lichtstr. 35, WSJ-386.2.09, CH-4002 Basel (Switzerland)], E-mail: nicolau.beckmann@novartis.com; Cannet, Catherine [Discovery Technologies, Novartis Institutes for BioMedical Research, Lichtstr. 35, WSJ-386.2.09, CH-4002 Basel (Switzerland); Karmouty-Quintana, Harry [Discovery Technologies, Novartis Institutes for BioMedical Research, Lichtstr. 35, WSJ-386.2.09, CH-4002 Basel (Switzerland); Meakins-Christie Laboratories, McGill University, Montreal, Canada H2X 2P2 (Canada); Tigani, Bruno; Zurbruegg, Stefan [Discovery Technologies, Novartis Institutes for BioMedical Research, Lichtstr. 35, WSJ-386.2.09, CH-4002 Basel (Switzerland); Ble, Francois-Xavier [Discovery Technologies, Novartis Institutes for BioMedical Research, Lichtstr. 35, WSJ-386.2.09, CH-4002 Basel (Switzerland); Respiratory Diseases Department, Novartis Institutes for BioMedical Research, CH-4056 Basel (Switzerland); Faculty of Pharmacy, University Louis Pasteur-Strasbourg-I, F-67401 Illkirch (France); Cremillieux, Yannick [University of Lyon-1, Laboratory of Nuclear Magnetic Resonance, Centre National de la Recherche Scientifique (CNRS), F-69622 Villeurbanne (France); Trifilieff, Alexandre [Respiratory Diseases Department, Novartis Institutes for BioMedical Research, CH-4056 Basel (Switzerland)

    2007-12-15

    Current techniques to evaluate the efficacy of potential treatments for airways diseases in preclinical models are generally invasive and terminal. In the past few years, the flexibility of magnetic resonance imaging (MRI) to obtain anatomical and functional information of the lung has been explored with the scope of developing a non-invasive approach for the routine testing of drugs in models of airways diseases in small rodents. With MRI, the disease progression can be followed in the same animal. Thus, a significant reduction in the number of animals used for experimentation is achieved, as well as minimal interference with their well-being and physiological status. In addition, under certain circumstances the duration of the observation period after disease onset can be shortened since the technique is able to detect changes before these are reflected in parameters of inflammation determined using invasive procedures. The objective of this article is to briefly address MRI techniques that are being used in experimental lung research, with special emphasis on applications. Following an introduction on proton techniques and MRI of hyperpolarized gases, the attention is shifted to the MRI analysis of several aspects of lung disease models, including inflammation, ventilation, emphysema, fibrosis and sensory nerve activation. The next subject concerns the use of MRI in pharmacological studies within the context of experimental lung research. A final discussion points towards advantages and limitations of MRI in this area.

  8. MRI of anterior cruciate ligament autografts

    Ogi, Shigeyuki; Ariizumi, Mitsuko; Yamagishi, Tsuneo [The Aoyama Tokyo Metropolitan office' s Hospital (Japan); Agata, Toshihiko; Tada, Shinpei; Fukuda, Kunihiko

    2000-09-01

    The purpose of this study was to assess the usefulness of MRI in the evaluation of autografts after anterior cruciate ligament reconstruction. The subjects were 110 patients with anterior cruciate ligament reconstruction using patellar tendon autografts who underwent clinical examination, MRI, and arthroscopy of the knee. T1- and T2-weighted MR images were obtained in sagittal plane. Clinical findings were categorized into three groups: normal, borderline, and abnormal. The MRI appearances of the autografts were categorized into three types: straight continuous band (type I), interrupted band (type II) and generalized increased intensity band (type III). The clinical findings and MRI findings were compared with arthroscopic findings. Ninety-six percent of the type I showed no autograft tear on arthroscopy. In comparison with the clinical findings, MRI was found to be well correlated with arthroscopic findings. In conclusion, if the clinical findings are normal, patients are to be followed-up without MRI and arthroscopy. However, if clinical findings are either borderline or abnormal, MRI should be performed prior to arthroscopy. (author)

  9. Application of functional MRI in epilepsy

    YU Ai-hong; LI Kun-cheng; PIAO Chang-fu; LI Hong-li

    2005-01-01

    Objective To review the recent development of functional MRI application in epilepsy. Data sources Both Chinese and English language literatures were researched using MEDLINE/ CD ROM (1996-2005) and the Chinese Biomedical Literature Disk (1996-2005). Study selection Published articles about functional MRI application and epilepsy were selected.Data extraction Data were mainly extracted from 38 articles which are listed in the reference section of this review.Results fMRI can be used to localize seizure foci through detecting these cerebral hemodynamic changes produced by epileptiform discharges. EEG-triggered fMRI, which has higher spatial and temporal resolution, helps to detect the spatiotemporal pattern of spike origin and propagation, and define localization of the epileptogenic focus. fMRI is also useful in language and memory cognitive function assessment and presurgical assessment of refractory epilepsy. Atypically distributed cognitive function areas can be detected by fMRI, because of cortical language and memory areas reorganization during long-term epileptic activity in patients with epilepsy. Conclusions fMRI technique plays a very important role in cognitive function and presurgical assessment of patients with epilepsy. It is meaningful for understanding pathogenesis of epilepsy.

  10. Recommendations for Real-Time Speech MRI

    Lingala, Sajan Goud; Sutton, Brad P.; Miquel, Marc E.; Nayak, Krishna S.

    2016-01-01

    Real-time magnetic resonance imaging (RT-MRI) is being increasingly used for speech and vocal production research studies. Several imaging protocols have emerged based on advances in RT-MRI acquisition, reconstruction, and audio-processing methods. This review summarizes the state-of-the-art, discusses technical considerations, and provides specific guidance for new groups entering this field. We provide recommendations for performing RT-MRI of the upper airway. This is a consensus statement stemming from the ISMRM-endorsed Speech MRI summit held in Los Angeles, February 2014. A major unmet need identified at the summit was the need for consensus on protocols that can be easily adapted by researchers equipped with conventional MRI systems. To this end, we provide a discussion of tradeoffs in RT-MRI in terms of acquisition requirements, a priori assumptions, artifacts, computational load, and performance for different speech tasks. We provide four recommended protocols and identify appropriate acquisition and reconstruction tools. We list pointers to open-source software that facilitate implementation. We conclude by discussing current open challenges in the methodological aspects of RT-MRI of speech. PMID:26174802

  11. MRI findings in acute Hendra virus meningoencephalitis

    Nakka, P.; Amos, G.J. [Department of Diagnostic Radiology, Princess Alexandra Hospital, Woolloongabba, Qld 4102 (Australia); Saad, N., E-mail: nivena100@hotmail.com [Department of Diagnostic Radiology, Princess Alexandra Hospital, Woolloongabba, Qld 4102 (Australia); Jeavons, S. [Department of Diagnostic Radiology, Princess Alexandra Hospital, Woolloongabba, Qld 4102 (Australia)

    2012-05-15

    Aim: To describe serial changes in brain magnetic resonance imaging (MRI) in acute human infection from two outbreaks of Hendra virus (HeV), relate these changes to disease prognosis, and compare HeV encephalitis to reported cases of Nipah virus encephalitis. Materials and methods: The MRI images of three human cases (two of which were fatal) of acute HeV meningoencephalitis were reviewed. Results: Cortical selectivity early in the disease is evident in all three patients, while deep white matter involvement appears to be a late and possibly premorbid finding. This apparent early grey matter selectivity may be related to viral biology or ribavirin pharmacokinetics. Neuronal loss is evident at MRI, and the rate of progression of MRI abnormalities can predict the outcome of the infection. In both fatal cases, the serial changes in the MRI picture mirrored the clinical course. Conclusion: This is the first comprehensive report of serial MRI findings in acute human cerebral HeV infection from two outbreaks. The cortical selectivity appears to be an early finding while deep white matter involvement a late, and possibly premorbid, finding. In both fatal cases, the serial changes in MRI mirrored the clinical course.

  12. Automatic probe artifact detection in MRI-guided cryoablation

    Liu, Xinyang; Tuncali, Kemal; Wells, William M.; Zientara, Gary P.

    2013-03-01

    Probe or needle artifact detection in 3D scans gives an approximate location for the tools inserted, and is thus crucial in assisting many image-guided procedures. Conventional needle localization algorithms often start with cropped images, where unwanted parts of raw scans are cropped either manually or by applying pre-defined masks. In cryoablation, however, the number of probes used, the placement and direction of probe insertion, and the portions of abdomen scanned differs significantly from case to case, and probes are often constantly being adjusted during the Probe Placement Phase. These features greatly reduce the practicality of approaches based on image cropping. In this work, we present a fully Automatic Probe Artifact Detection method, APAD, that works directly on uncropped raw MRI images, taken during the Probe Placement Phase in 3Tesla MRI-guided cryoablation. The key idea of our method is to first locate an initial 2D line strip within a slice of the MR image which approximates the position and direction of the 3D probes bundle, noting that cryoprobes or biopsy needles create a signal void (black) artifact in MRI with a bright cylindrical border. With the initial 2D line, standard approaches to detect line structures such as the 3D Hough Transform can be applied to quickly detect each probe's axis. By comparing with manually labeled probes, the analysis of 5 patient treatment cases of kidney cryoablation with varying probe placements demonstrates that our algorithm combined with standard 3D line detection is an accurate and robust method to detect probe artifacts.

  13. A non-alcoholic Wernicke’s encephalopathy case with atypical MRI findings: Clinic versus radiology

    Alpaydin, Sezin; Sirin, Hadiye; Calli, Cem; Celebisoy, Neşe

    2015-01-01

    Wernicke's Encephalopathy is an acute neuropsychiatric syndrome that can be seen in both alcohol abusers and non-alcoholic population as a result of thiamine deficiency. We herein report a non-alcoholic patient with typical clinical presentations but atypical MRI findings. Early clinical suspicion of WE is especially important in non-alcoholic patients with atypical MRI findings. The diagnosis of this group is more difficult to make and the prognosis of the syndrome mostly depends on early initiation of thiamine supplementation. PMID:26306933

  14. Acute verbal dyspraxia, a rare presentation in multiple sclerosis: a case report with MRI localization.

    Jaffe, Stephen L; Glabus, Michael F; Kelley, Roger E; Minagar, Alireza

    2003-12-01

    Cortical speech disorders rarely occur in multiple sclerosis (MS). We report a patient with relapsing-remitting MS, who presented with acute verbal dyspraxia. Magnetic resonance imaging (MRI) demonstrated an acute T2/Flair hyperintense, primarily white matter lesion underlying the middle third of the inferior frontal gyrus. The verbal dyspraxia cleared beginning 48 hours after the initiation of iv dexamethasone. Follow-up MRI demonstrated qualitative and quantitative diminution of the hyperintensity. This is the first report of a clinically definite MS patient with acute verbal dyspraxia. Moreover, there was a suggestive localization of verbal praxis to Brodmann areas 44/45.

  15. Developments in boron magnetic resonance imaging (MRI)

    Schweizer, M.

    1995-11-01

    This report summarizes progress during the past year on maturing Boron-11 magnetic resonance imaging (MRI) methodology for noninvasive determination of BNCT agents (BSH) spatially in time. Three major areas are excerpted: (1) Boron-11 MRI of BSH distributions in a canine intracranial tumor model and the first human glioblastoma patient, (2) whole body Boron-11 MRI of BSH pharmacokinetics in a rat flank tumor model, and (3) penetration of gadolinium salts through the BBB as a function of tumor growth in the canine brain.

  16. 6{sup th} interventional MRI symposium. Abstracts

    NONE

    2006-07-01

    The ongoing progress in the field of interventional MRI and the great success of our last symposium 2004 in Boston have stimulated us to organize the 6th Interventional MRI Symposium to be held September 15-16, 2006 in Leipzig. This meeting will highlight ground-breaking research as well as cutting-edge reports from many groups. The symposium also provides a forum to network with leaders and innovators in the field. Session topics are: intraoperative MRI, vascular applications, targeted drug delivery, cryotherapy, thermometry, pulse sequences, LITT, percutaneous procedures, navigation, robotics, focused ultrasound. (uke)

  17. Late Adverse Events after Enhanced and Unenhanced MRI and CT

    Azzouz, Manal; Rømsing, Janne; Thomsen, Henrik S.

    2014-01-01

    of LAEs was significantly higher in the enhanced MRI (38%) and CT (27%) groups than unenhanced MRI (20%) and CT (16%) groups. The frequency of nausea, dizziness, abdominal pain and diarrhoea was significantly higher in the enhanced MRI group than in the MRI control group, while taste sensation...

  18. Development and validation of an MRI reference criterion for defining a positive SIJ MRI in spondyloarthritis

    Weber, Ulrich; Zubler, Veronika; Pedersen, Susanne J

    2012-01-01

    OBJECTIVE: To validate an MRI reference criterion for a positive SIJ MRI based on the level of confidence in classification of spondyloarthritis (SpA) by expert MRI readers. METHODS: Four readers assessed SIJ MRI in two inception cohorts (A/B) of 157 consecutive back pain patients ≤50 years...... (0=definitely not; 10=definite). The MRI reference criterion was pre-specified as the majority of readers recording a confidence of 8-10; absence of SpA required all readers to record Non-SpA (confidence 0-4). We calculated inter-reader reliability and agreement between MRI-based and clinical...... classification using kappa statistics. We estimated cut-off values for MRI lesions attaining specificity `0.90 for SpA. RESULTS: 76.4%/71.6% of subjects in cohorts A/B met the MRI criterion. Kappa values for inter-reader agreement were 0.76/0.80, and between MRI-based and clinical assessment 0.93/0.57. Using...

  19. Diagnosis of Chiari III malformation by second trimester fetal MRI with postnatal MRI and CT correlation

    Smith, Alice B.; Glenn, Orit A. [University of California, San Francisco, Department of Radiology, San Francisco, CA (United States); Gupta, Nalin [University of California, San Francisco, Department of Neurosurgery, San Francisco, CA (United States); Otto, Carl [California Pacific Medical Center, Department of Perinatology, San Francisco, CA (United States)

    2007-10-15

    We report a case of Chiari III malformation diagnosed by fetal MRI. Ultrasound (US) performed at a gestational age of 18 weeks demonstrated a posterior skull base cyst. Repeat US at 19 weeks demonstrated neural tissue in the cyst, consistent with an encephalocele. MR imaging at 23 weeks confirmed the presence of an occipital encephalocele, demonstrated additional bony defect in the upper cervical spine, and identified abnormal morphology and position of the brainstem consistent with the diagnosis of Chiari III. Postnatal MRI and CT confirmed the fetal MRI findings and demonstrate the utility of fetal MRI in the early evaluation of songraphically detected posterior fossa abnormalities. (orig.)

  20. Utility of functional MRI in pediatric neurology.

    Freilich, Emily R; Gaillard, William D

    2010-01-01

    Functional MRI (fMRI), a tool increasingly used to study cognitive function, is also an important tool for understanding not only normal development in healthy children, but also abnormal development, as seen in children with epilepsy, attention-deficit/hyperactivity disorder, and autism. Since its inception almost 15 years ago, fMRI has seen an explosion in its use and applications in the adult literature. However, only recently has it found a home in pediatric neurology. New adaptations in study design and technologic advances, especially the study of resting state functional connectivity as well as the use of passive task design in sedated children, have increased the utility of functional imaging in pediatrics to help us gain understanding into the developing brain at work. This article reviews the background of fMRI in pediatrics and highlights the most recent literature and clinical applications.

  1. PET/MRI in cancer patients

    Kjær, Andreas; Loft, Annika; Law, Ian;

    2013-01-01

    Combined PET/MRI systems are now commercially available and are expected to change the medical imaging field by providing combined anato-metabolic image information. We believe this will be of particular relevance in imaging of cancer patients. At the Department of Clinical Physiology, Nuclear...... Medicine & PET at Rigshospitalet in Copenhagen we installed an integrated PET/MRI in December 2011. Here, we describe our first clinical PET/MR cases and discuss some of the areas within oncology where we envision promising future application of integrated PET/MR imaging in clinical routine. Cases...... described include brain tumors, pediatric oncology as well as lung, abdominal and pelvic cancer. In general the cases show that PET/MRI performs well in all these types of cancer when compared to PET/CT. However, future large-scale clinical studies are needed to establish when to use PET/MRI. We envision...

  2. MRI findings of Guillain-Barre syndrome

    Park, Won Kyu; Lee, Hwa Jin; Byun, Woo Mok [Yeungnam Univ. College of Medicine, Taegu (Korea, Republic of)

    1997-04-01

    To evaluate MRI findings of Guillain-Barre syndrome. In six patients with Guillain-Barre syndrome diagnosed by clinical, cerebrospinal fluid and electrophysiologic findings, a retrospective review of MR findings was conducted. Follow-up MRI scans were carried out in two patients showing minimal clinical improvement. Marked or moderate enhancement of thickened nerve roots was seen in all cases on gadopentetate dimeglumine enhanced axial T1-weighted images. Two patterns were seen; one was even enhancement of both anterior and posterior nerve roots (n=1) and the other was enhancement of anterior nerve roots only (n=5). Enhancement and thickness of nerve roots was seen to have slightly decreased on MRI follow-up at 32 and 50 days; clinical and electrophysiologic examination showed minimal improvement. Although MRI findings of nerve root enhancement are nonspecific and can be seen in neoplastic and other inflammatory diseases, the enhancement of thickened anterior nerve roots within the cal sac suggests Guillain-Barre syndrome.

  3. Magnetic Resonance, Functional (fMRI) -- Brain

    ... 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 ...

  4. MRI Helps Assess Fetal Brain Abnormalities

    ... authors. The study was published Dec. 14 in The Lancet . "Adding an MRI scan when a problem is ... practice as soon as possible, he said. SOURCE: The Lancet , news release, Dec. 14, 2016 HealthDay Copyright (c) ...

  5. Organizing Knowing in Interdisciplinary MRI Practice

    Yoshinaka, Yutaka

    This paper addresses organizational knowledge practices pertaining to the interdisciplinary work of Magnetic Resonance Imaging (MRI) at a hospital radiology department. The setting occasions an interesting venue for exploring domestication of MRI as it unfolds in distributed settings of collective...... envisaged to deal with the department’s appropriation of a new MRI scanner, occasioned by the replacement of an existing model. Work was reorganised to reflect this aspect in the practice protocols from early on, where personnel previously assigned only to other imaging modalities such as the department......'s CT-scan and X-ray machines, were to take on MRI scanning, on an albeit rotational basis. Opening up to a broader group of operators to the scanning practice was to allow for organizational flexibility and a broader basis for competence building among radiology staff, where different occupational...

  6. Accuracy of MRI in Growth Plate Measurement

    Shiguetomi Medina, Juan Manuel; Rahbek, Ole; Ringgaard, Steffen

    2013-01-01

    was measured and compared to histology. Results. Histology measurements showed a mean growth plate thickness of 467 μm (SD = 82.2). The mean growth plate thickness measured in the 7T MR images was 465 μm (SD = 62.2) and 1325 μm (SD=183.5) on 1.5 MRI measurements. We found a better correlation between...... the growth plate thickness measured on the 7T MRI and histology samples compared to 1.5T, where the accuracy was poor. Conclusion. The growth plate can be identified and measured with high accuracy using 7T MRI. 1.5T MRI can only describe some morphological characteristics; its poor resolution impedes to do...

  7. Superresolution improves MRI cortical segmentation with FACE

    Eskildsen, Simon Fristed; Manjón, José V.; Coupé, Pierrick

    Brain cortical surface extraction from MRI has applications for measurement of gray matter (GM) atrophy, functional mapping, source localization and preoperative neurosurgical planning. Accurate cortex segmentation requires high resolution morphological images and several methods for extracting...

  8. 2015 MICCAI Workshop on Computational Diffusion MRI

    Ghosh, Aurobrata; Kaden, Enrico; Rathi, Yogesh; Reisert, Marco

    2016-01-01

    These Proceedings of the 2015 MICCAI Workshop “Computational Diffusion MRI” offer a snapshot of the current state of the art on a broad range of topics within the highly active and growing field of diffusion MRI. The topics vary from fundamental theoretical work on mathematical modeling, to the development and evaluation of robust algorithms, new computational methods applied to diffusion magnetic resonance imaging data, and applications in neuroscientific studies and clinical practice. Over the last decade interest in diffusion MRI has exploded. The technique provides unique insights into the microstructure of living tissue and enables in-vivo connectivity mapping of the brain. Computational techniques are key to the continued success and development of diffusion MRI and to its widespread transfer into clinical practice. New processing methods are essential for addressing issues at each stage of the diffusion MRI pipeline: acquisition, reconstruction, modeling and model fitting, image processing, fiber t...

  9. Multichannel Compressive Sensing MRI Using Noiselet Encoding

    Pawar, Kamlesh; Zhang, Jingxin

    2014-01-01

    The incoherence between measurement and sparsifying transform matrices and the restricted isometry property (RIP) of measurement matrix are two of the key factors in determining the performance of compressive sensing (CS). In CS-MRI, the randomly under-sampled Fourier matrix is used as the measurement matrix and the wavelet transform is usually used as sparsifying transform matrix. However, the incoherence between the randomly under-sampled Fourier matrix and the wavelet matrix is not optimal, which can deteriorate the performance of CS-MRI. Using the mathematical result that noiselets are maximally incoherent with wavelets, this paper introduces the noiselet unitary bases as the measurement matrix to improve the incoherence and RIP in CS-MRI, and presents a method to design the pulse sequence for the noiselet encoding. This novel encoding scheme is combined with the multichannel compressive sensing (MCS) framework to take the advantage of multichannel data acquisition used in MRI scanners. An empirical RIP a...

  10. MRI Reporter Genes for Noninvasive Molecular Imaging

    Caixia Yang

    2016-05-01

    Full Text Available Magnetic resonance imaging (MRI is one of the most important imaging technologies used in clinical diagnosis. Reporter genes for MRI can be applied to accurately track the delivery of cell in cell therapy, evaluate the therapy effect of gene delivery, and monitor tissue/cell-specific microenvironments. Commonly used reporter genes for MRI usually include genes encoding the enzyme (e.g., tyrosinase and β-galactosidase, the receptor on the cells (e.g., transferrin receptor, and endogenous reporter genes (e.g., ferritin reporter gene. However, low sensitivity limits the application of MRI and reporter gene-based multimodal imaging strategies are common including optical imaging and radionuclide imaging. These can significantly improve diagnostic efficiency and accelerate the development of new therapies.

  11. MRI manifestations of enlarged superior ophthalmic vein

    WEI Rui-li; MA Xiao-ye; CAI Ji-ping; ZHU Huang

    2002-01-01

    Objective:To assess MRI in the evaluation of enlarged superior ophthalmic vein (SOV). Methods: MRI manifestations and etiology of forty-six patients with enlarged SOV were analyzed. Results: SOV enlargement was noted to occur in carotid-cavernous fistula, ophthalmic Graves'disease, Tolosa-Hunt syndrome, inflammation at the apex of the orbit, orbital pseudotumor and thrombosis of cavernous sinus. The dilated vein appeared as signal void tubular shadows on both T1 and T2 weighted images. The diameter of the enlarged vein was 3.5-6.0 mm. Extraocular muscle enlargement, orbital pathologies, enlarged carotid cavernous sinus etc were also revealed by MRI. Conclusion: The dilated SOV may be well demonstrated by MRI. The etiological diagnosis of enlarged SOV can be made in combination with the associated findings.

  12. MRI finding of ethylmalonic encephalopathy: case report

    Kim, Jin Yong; Lee, Shi Kyung; Han, Chun Hwan; Rho, Eun Jin [Kangnam General Hospital Public Corporation, Seoul (Korea, Republic of)

    2002-12-01

    Ethylmalonic encephalopathy is a rare syndrom characterized by developmental delay, acrocyanosis, petechiae, chronic diarrhea, and ethylmalonic, lactic, and methylsuccinic aciduria. We report the MRI finding of ethylmalonic encephalopathy including previously unreported intracranial hematoma.

  13. PET/MRI in cancer patients

    Kjær, Andreas; Loft, Annika; Law, Ian

    2013-01-01

    Combined PET/MRI systems are now commercially available and are expected to change the medical imaging field by providing combined anato-metabolic image information. We believe this will be of particular relevance in imaging of cancer patients. At the Department of Clinical Physiology, Nuclear...... described include brain tumors, pediatric oncology as well as lung, abdominal and pelvic cancer. In general the cases show that PET/MRI performs well in all these types of cancer when compared to PET/CT. However, future large-scale clinical studies are needed to establish when to use PET/MRI. We envision...... that PET/MRI in oncology will prove to become a valuable addition to PET/CT in diagnosing, tailoring and monitoring cancer therapy in selected patient populations....

  14. On clustering fMRI time series

    Goutte, C; Toft, P; Rostrup, E

    1999-01-01

    Analysis of fMRI time series is often performed by extracting one or more parameters for the individual voxels. Methods based, e.g., on various statistical tests are then used to yield parameters corresponding to probability of activation or activation strength. However, these methods do not indi......Analysis of fMRI time series is often performed by extracting one or more parameters for the individual voxels. Methods based, e.g., on various statistical tests are then used to yield parameters corresponding to probability of activation or activation strength. However, these methods do...... between the activation stimulus and the fMRI signal. We present two different clustering algorithms and use them to identify regions of similar activations in an fMRI experiment involving a visual stimulus....

  15. MRI of the Body (Chest, Abdomen, Pelvis)

    ... receive injections of gadolinium contrast material except when absolutely necessary for medical treatment. See the Safety page ... MRI scanners are air-conditioned and well-lit. Music may be played through the headphones to help ...

  16. Detection and Demarcation of Tumor using Vector Quantization in MRI images

    Kekre, H B; Gharge, Saylee M

    2010-01-01

    Segmenting a MRI images into homogeneous texture regions representing disparate tissue types is often a useful preprocessing step in the computer-assisted detection of breast cancer. That is why we proposed new algorithm to detect cancer in mammogram breast cancer images. In this paper we proposed segmentation using vector quantization technique. Here we used Linde Buzo-Gray algorithm (LBG) for segmentation of MRI images. Initially a codebook of size 128 was generated for MRI images. These code vectors were further clustered in 8 clusters using same LBG algorithm. These 8 images were displayed as a result. This approach does not leads to over segmentation or under segmentation. For the comparison purpose we displayed results of watershed segmentation and Entropy using Gray Level Co-occurrence Matrix along with this method.

  17. Post-traumatic upper cervical subluxation visualized by MRI: a case report

    Demetrious James

    2007-12-01

    Full Text Available Abstract Background This paper describes MRI findings of upper cervical subluxation due to alar ligament disruption following a vehicular collision. Incidental findings included the presence of a myodural bridge and a spinal cord syrinx. Chiropractic management of the patient is discussed. Case presentation A 21-year old female presented with complaints of acute, debilitating upper neck pain with unremitting sub-occipital headache and dizziness following a vehicular collision. Initial emergency department and neurologic investigations included x-ray and CT evaluation of the head and neck. Due to persistent pain, the patient sought chiropractic care. MRI of the upper cervical spine revealed previously unrecognized clinical entities. Conclusion This case highlights the identification of upper cervical ligamentous injury that produced vertebral subluxation following a traumatic incident. MRI evaluation provided visualization of previously undetected injury. The patient experienced improvement through chiropractic care.

  18. Can the painDETECT Questionnaire score and MRI help predict treatment outcome in rheumatoid arthritis

    Rifbjerg-Madsen, Signe; Christensen, Anton Wulf; Boesen, Mikael

    2014-01-01

    -one aspect of chronic pain. In contrast, other patients report good treatment response, although imaging shows signs of inflammation, which could indicate a possible enhancement of descending pain inhibitory mechanisms. When assessing disease activity in patients with central sensitisation, the commonly used......-modifying antirheumatic drug treatment, or (B) initiating or switching to biological therapy. We anticipate that 100 patients will be enrolled, tested and reassessed after 4 months of treatment. DATA COLLECTION INCLUDES: Clinical data, conventional MRI, DCE-MRI, blood samples and patient-reported outcomes. ETHICS......-inflammatory treatment, to explore the prognostic value of a screening questionnaire for central sensitisation, hand inflammation assessed by conventional MRI, and the interaction between them regarding treatment outcome evaluated by clinical status (DAS28-CRP). For the purpose of further exploratory analyses, dynamic...

  19. Simultaneous PET/MRI: Impact on cancer management-A comprehensive review of cases

    Amarnath Jena

    2014-01-01

    Full Text Available The metabolic mapping of malignancy in whole body in a single examination by PET/CT has gained widespread acceptance where the CT provides an anatomical correlate for the PET. MRI offers advantage over CT in providing better anatomical information owing to its high soft tissue resolution especially in brain, liver, neck, pelvis and bone marrow. Simultaneous PET/MRI is a new multimodal imaging modality that is expected to improve the diagnostic performance of imaging wherein better anatomical and metabolic information can be acquired at the same time and space during a single examination time. Also, MR attributes like diffusion, perfusion and spectroscopy may further add to its diagnostic potential. In this article, we present our initial experience in illustrated cases done with simultaneous PET/MRI and outline its potential for several clinical applications in oncology.

  20. Can unenhanced multiparametric MRI substitute gadolinium-enhanced MRI in the characterization of vertebral marrow infiltrative lesions?

    Dalia Z. Zidan

    2014-06-01

    Conclusion: Unenhanced-multiparametric MRI is compatible with gadolinium-enhanced MRI in reliable characterization of marrow infiltrative lesions. The routine MRI protocol of cancer patients should be altered to accommodate the evolving MRI technology and cost effectively substitute the need for a gadolinium enhanced scan.

  1. Relationship between diffusion parameters derived from intravoxel incoherent motion MRI and perfusion measured by dynamic contrast-enhanced MRI of soft tissue tumors.

    Marzi, Simona; Stefanetti, Linda; Sperati, Francesca; Anelli, Vincenzo

    2016-01-01

    Our aim was to evaluate the link between diffusion parameters measured by intravoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI) and the perfusion metrics obtained with dynamic contrast-enhanced (DCE) MRI in soft tissue tumors (STTs). Twenty-eight patients affected by histopathologically confirmed STT were included in a prospective study. All patients underwent both DCE MRI and IVIM DWI. The perfusion fraction f, diffusion coefficient D and perfusion-related diffusion coefficient D* were estimated using a bi-exponential function to fit the DWI data. DCE MRI was acquired with a temporal resolution of 3-5 s. Maps of the initial area under the gadolinium concentration curve (IAUGC), time to peak (TTP) and maximum slope of increase (MSI) were derived using commercial software. The relationships between the DCE MRI and IVIM DWI measurements were assessed by Spearman's test. To exclude false positive results under multiple testing, the false discovery rate (FDR) procedure was applied. The Mann-Whitney test was used to evaluate the differences between all variables in patients with non-myxoid and myxoid STT. No significant relationship was found between IVIM parameters and any DCE MRI parameters. Higher f and D*f values were found in non-myxoid tumors compared with myxoid tumors (p = 0.004 and p = 0.003, respectively). MSI was significantly higher in non-myxoid tumors than in myxoid tumors (p = 0.029). From the visual assessments of single clinical cases, both f and D*f maps were in satisfactory agreement with DCE maps in the extreme cases of an avascular mass and a highly vascularized mass, whereas, for tumors with slight vascularity or with a highly heterogeneous perfusion pattern, this association was not straightforward. Although IVIM DWI was demonstrated to be feasible in STT, our data did not support evident relationships between perfusion-related IVIM parameters and perfusion measured by DCE MRI.

  2. Utility of Early MRI in the Diagnosis and Management of Acute Spontaneous Intracerebral Hemorrhage

    Wijman, Christine A.C.; Venkatasubramanian, Chitra; Bruins, Sara; Fischbein, Nancy; Schwartz, Neil

    2010-01-01

    Background The optimal diagnostic evaluation for spontaneous intracerebral hemorrhage (ICH) remains controversial. In this retrospective study, we assessed the utility of early magnetic resonance imaging (MRI) in ICH diagnosis and management. Methods Eighty-nine (72%) of 123 patients with spontaneous ICH underwent a brain CT and MRI within 30 days of ICH onset. Seventy patients with a mean age of 62 ± 15 years were included. A stroke neurologist and a general neurologist, each blinded to the final diagnosis, independently reviewed the admission data and the initial head CT and then assigned a presumed ICH cause under 1 of 9 categories. ICH cause was potentially modified after subsequent MRI review. The final ‘gold standard’ ICH etiology was determined after review of the complete medical record by an independent investigator. Change in diagnostic category and confidence and the potential impact on patient management were systematically recorded. Results Mean time to MRI was 3 ± 5 days. Final ICH diagnosis was hypertension or cerebral amyloid angiopathy (CAA) in 50% of patients. After MRI review the stroke neurologist changed diagnostic category in 14%, diagnostic confidence in an additional 23% and management in 20%, and the general neurologist did so in 19, 21 and 21% of patients, respectively. MRI yield was highest in ICH secondary to ischemic stroke, CAA, vascular malformations and neoplasms, and did not differ by age, history of hypertension, hematoma location or the presence of intraventricular hemorrhage. Conclusions The results of this study suggest potential additive clinical benefit of early MRI in patients with spontaneous ICH. PMID:20733299

  3. MRI and MRS of human brain tumors.

    Hou, Bob L; Hu, Jiani

    2009-01-01

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

  4. PET/MRI. Methodology and clinical applications

    Carrio, Ignasi [Autonomous Univ. of Barcelona, Hospital Sant Pau (Spain). Dept. Medicina Nuclear; Ros, Pablo (ed.) [Univ. Hospitals Case, Medical Center, Cleveland, OH (United States). Dept. of Radiology

    2014-04-01

    Provides detailed information on the methodology and equipment of MRI-PET. Covers a wide range of clinical applications in oncology, cardiology, and neurology. Written by an international group of experts in MRI and PET. PET/MRI is an exciting novel diagnostic imaging modality that combines the precise anatomic and physiologic information provided by magnetic resonance imaging (MRI) with the molecular data obtained with positron emission tomography (PET). PET/MRI offers the promise of a simplified work flow, reduced radiation, whole-body imaging with superior soft tissue contrast, and time of flight physiologic information. It has been described as the pathway to molecular imaging in medicine. In compiling this textbook, the editors have brought together a truly international group of experts in MRI and PET. The book is divided into two parts. The first part covers methodology and equipment and comprises chapters on basic molecular medicine, development of specific contrast agents, MR attenuation and validation, quantitative MRI and PET motion correction, and technical implications for both MRI and PET. The second part of the book focuses on clinical applications in oncology, cardiology, and neurology. Imaging of major neoplasms, including lymphomas and tumors of the breast, prostate, and head and neck, is covered in individual chapters. Further chapters address functional and metabolic cardiovascular examinations and major central nervous system applications such as brain tumors and dementias. Risks, safety aspects, and healthcare costs and impacts are also discussed. This book will be of interest to all radiologists and nuclear medicine physicians who wish to learn more about the latest developments in this important emerging imaging modality and its applications.

  5. Pharmacological fMRI; a clinical exploration

    Goekoop, R.

    2006-01-01

    Dit proefschrift beschrijft de resultaten van een verkennend onderzoek naar een nieuwe techniek die gebruikt kan worden om de effecten van geneesmiddelen op hersenaktiviteit af te beelden: pharmacologische functionele magnetic resonance imaging (farmacologische fMRI of phMRI). Met behulp van deze techniek werden de effecten onderzocht van drie verschillende medicijnen (de bètablokker propranolol, de selectieve oestrogeen-receptor modulator (SERM) raloxifene en de cholinesteraseremmer galantam...

  6. Quantitative Cerebral Blood Flow Measurements Using MRI

    Muir, Eric R; Watts, Lora Talley; Tiwari, Yash Vardhan; Bresnen, Andrew; Timothy Q Duong

    2014-01-01

    Magnetic resonance imaging utilized as a quantitative and noninvasive method to image cerebral blood flow. The two most common techniques used to detect cerebral blood flow are dynamic susceptibility contrast (DSC) perfusion MRI and arterial spin labeling perfusion MRI. Herein we describe the use of these two techniques to measure cerebral blood flow in rodents, including methods, analysis, and important considerations when utilizing these techniques.

  7. POEMS syndrome: radiographic appearance with MRI correlation

    Chong, Suzanne T. [Western Pennsylvania Hospital, Department of Diagnostic Radiology, Pittsburgh, Pennsylvania (United States); University of Michigan, Department of Radiology, Ann Arbor, MI (United States); Beasley, H.S. [Western Pennsylvania Hospital, Department of Diagnostic Radiology, Pittsburgh, Pennsylvania (United States); Daffner, Richard H. [Allegheny General Hospital, Department of Diagnostic Radiology, Section of Musculoskeletal/Trauma Radiology, Pittsburgh, Pennsylvania (United States)

    2006-09-15

    POEMS syndrome is a rare disorder in which patients present with the hallmark signs of polyneuropathy, organomegaly, endocrinopathy, M protein and skin changes. Many other clinical findings are also often present, most notably osseous lesions. The MRI appearance of the bony lesions in POEMS syndrome has been described in five cases, four of which are in the non-English literature. We report the MRI appearance of the osseous lesions in a patient with POEMS syndrome who presented with sciatic neuropathy. (orig.)

  8. Infantile Refsum disease: serial evaluation with MRI.

    Cakirer, Sinan; Savas, Mahmut R

    2005-02-01

    Refsum disease is a rare metabolic disorder, which is characterized by the accumulation of phytanic acid in the blood and tissues, including the brain. A variant of this condition that occurs in young children is called infantile Refsum disease. The MRI findings of symmetrical signal change involving the corticospinal tracts, cerebellar dentate nuclei, and corpus callosum are characteristic. We report the serial MRI findings of a child with this rare metabolic disorder.

  9. Infantile Refsum disease: serial evaluation with MRI

    Cakirer, Sinan; Savas, Mahmut R. [Sisli Etfal Hospital, Neuroradiology Section, Department of Radiology, Istanbul (Turkey)

    2005-02-01

    Refsum disease is a rare metabolic disorder, which is characterized by the accumulation of phytanic acid in the blood and tissues, including the brain. A variant of this condition that occurs in young children is called infantile Refsum disease. The MRI findings of symmetrical signal change involving the corticospinal tracts, cerebellar dentate nuclei, and corpus callosum are characteristic. We report the serial MRI findings of a child with this rare metabolic disorder. (orig.)

  10. MRI Brain Tumor Segmentation Methods- A Review

    Gursangeet, Kaur; Jyoti, Rani

    2016-01-01

    Medical image processing and its segmentation is an active and interesting area for  researchers. It has reached at the tremendous place in diagnosing tumors after the discovery of CT and MRI. MRI is an useful tool to detect the brain tumor and segmentation is performed to carry out the useful portion from an image. The purpose of this paper is to provide an overview of different image segmentation methods like watershed algorithm, morphological operations, neutrosophic sets, thresholding, K-...

  11. Vertebral involvement in SAPHO syndrome: MRI findings

    Nachtigal, A.; Cardinal, E.; Bureau, N.J. [Dept. of Radiology, Univ. de Montreal, QC (Canada); Sainte-Marie, L.G. [Dept. of Internal Medicine, Univ. de Montreal, QC (Canada); Milette, F. [Department of Pathology, Univ. de Montreal, QC (Canada)

    1999-03-01

    We report on the MRI findings in the vertebrae and surrounding soft tissues in two patients with the SAPHO syndrome (Synovitis, Acne, Pustulosis, Hyperostosis, Osteitis). The MRI findings include abnormal bone marrow signal, either focal or diffuse, of the vertebral bodies and posterior elements; hyperintense paravertebral soft tissue swelling and abnormal signal of the intervertebral discs. These changes are consistent with discitis and osteitis. (orig.) With 6 figs., 17 refs.

  12. Shoulder MRI after surgical treatment of instability

    Vahlensieck, Martin [University of Bonn, Department of Radiology, Sigmund-Freud-Strasse 25, 53105 Bonn (Germany); Lang, Philipp [University of California San Francisco, Department of Radiology, 505 Pamassus Avenue, San Francisco, CA 94143 (United States); Wagner, Ulli [University of Bonn, Department of Orthopedic Surgery, Sigmund-Freud-Strasse 25, 53105 Bonn (Germany); Moeller, Frank [University of Bonn, Department of Orthopedic Surgery, Sigmund-Freud-Strasse 25, 53105 Bonn (Germany); Deimling, Urs van [University of Bonn, Department of Orthopedic Surgery, Sigmund-Freud-Strasse 25, 53105 Bonn (Germany); Genant, H.K. [University of California San Francisco, Department of Radiology, 505 Pamassus Avenue, San Francisco, CA 94143 (United States); Schild, Hans H. [University of Bonn, Department of Radiology, Sigmund-Freud-Strasse 25, 53105 Bonn (Germany)

    1999-04-01

    Objective: To analyze magnetic resonance imaging (MRI) findings of the shoulder after an instability operation. Materials and methods: Physical examinations, radiographs and MRI of 10 patients after anterior glenoid bone block insertion for ventral instability were compared. MRI included T{sub 1}-weighted spin-echo (TR=600, TE=20 ms) and T{sub 2}*-weighted gradient-echo sequences (TE=600, TE=18, Flip=30 deg.) in the axial, oblique-coronal and oblique-sagittal planes. Results: No patient suffered from recurrent subluxation. We found fusion of the bone block with the anterior glenoid in seven cases, dislocation of the bone block without contact to the glenoid in one case, and no visible bone block in two cases. On MRI, the bone block showed either signal intensity equivalent to fatty bone marrow (n=4) or was devoid of signal consistent with cortical bone or bone sclerosis (n=4). In all patients, a low signal intensity mass, 2-4 cm in diameter, was visible next to the glenoid insertion site. Conclusion: Insertion of a bone block onto the anterior glenoid induces formation of scar tissue, increasing the stability of the shoulder joint. This scar is well visible on MRI and forms independently of the behavior of the bone block itself. MRI is ideally suited for evaluating postoperative shoulder joints after bone-grafting procedures.

  13. Diffusion MRI and its Role in Neuropsychology.

    Mueller, Bryon A; Lim, Kelvin O; Hemmy, Laura; Camchong, Jazmin

    2015-09-01

    Diffusion Magnetic Resonance Imaging (dMRI) is a popular method used by neuroscientists to uncover unique information about the structural connections within the brain. dMRI is a non-invasive imaging methodology in which image contrast is based on the diffusion of water molecules in tissue. While applicable to many tissues in the body, this review focuses exclusively on the use of dMRI to examine white matter in the brain. In this review, we begin with a definition of diffusion and how diffusion is measured with MRI. Next we introduce the diffusion tensor model, the predominant model used in dMRI. We then describe acquisition issues related to acquisition parameters and scanner hardware and software. Sources of artifacts are then discussed, followed by a brief review of analysis approaches. We provide an overview of the limitations of the traditional diffusion tensor model, and highlight several more sophisticated non-tensor models that better describe the complex architecture of the brain's white matter. We then touch on reliability and validity issues of diffusion measurements. Finally, we describe examples of ways in which dMRI has been applied to studies of brain disorders and how identified alterations relate to symptomatology and cognition.

  14. Pediatric multifocal liver lesions evaluated by MRI

    Majed Almotairi

    2015-01-01

    Full Text Available Objective: The purpose of this study is to present our experience with MRI evaluation of multifocal liver lesions in children and describe the MRI characteristics of these lesions. Patients and Methods: A retrospective review of consecutive MRI exams performed for the evaluation of multiple liver lesions between 1 January 2007 and 31 December 2012 was done to note the number of lesions, the size of the largest lesion, MR signal characteristics, and background liver. Final diagnosis was assigned to each case based on pathology in the available cases and a combination of clinical features, imaging features, and follow-up in the remaining cases. Results: A total of 48 children (22 boys, 26 girls; age between 3 months and 18 years with average age 10.58 years and median age 11 years were included in the study. Totally 51 lesion diagnoses were seen in 48 children that included 17 focal nodular hyperplasia (FNH, 8 hemangiomas, 7 metastases, 6 regenerative nodules, 3 adenomas, 3 abscesses, and one each of angiomyolipoma, epithelioid hemangioendothelioma, focal fatty infiltration, hepatocellular carcinoma, hepatic infarction, nodular regenerative hyperplasia, and hepatic cyst. Background liver was normal in 33, cirrhotic in 10, fatty in 3, and siderotic in 2 children. Most FNH, hemangiomas, and regenerative nodules showed characteristic MRI features, while metastases were variable in signal pattern. Conclusion: Many commonly seen multifocal liver lesions in children have characteristic MRI features. MRI can help to arrive at reasonable differential diagnoses for multifocal liver lesions in children and guide further investigation and management.

  15. MRI of perinatal brain injury

    Rutherford, Mary; Allsop, Joanna [Imperial College, Robert Steiner MR Unit, Perinatal Imaging, MRC Clinical Sciences Centre, Hammersmith Hospital, London (United Kingdom); Martinez Biarge, Miriam [La Paz University Hospital, Dept of Neonatology, Madrid (Spain); Counsell, Serena [Imperial College, Robert Steiner MR Unit, Neonatal Medicine, MRC Clinical Sciences Centre, Hammersmith Hospital, London (United Kingdom); Cowan, Frances [Imperial College, Dept of Paediatrics, Hammersmith Hospital, London (United Kingdom)

    2010-06-15

    MRI is invaluable in assessing the neonatal brain following suspected perinatal injury. Good quality imaging requires adaptations to both the hardware and the sequences used for adults or older children. The perinatal and postnatal details often predict the pattern of lesions sustained and should be available to aid interpretation of the imaging findings. Perinatal lesions, the pattern of which can predict neurodevelopmental outcome, are at their most obvious on conventional imaging between 1 and 2 weeks from birth. Very early imaging during the first week may be useful to make management decisions in ventilated neonates but brain abnormalities may still be subtle using conventional sequences. Diffusion-weighted imaging (DWI) is very useful for the early identification of ischaemic tissue in the neonatal brain but may underestimate the final extent of injury, particularly basal ganglia and thalamic lesions. MR imaging is an excellent predictor of outcome following perinatal brain injury and can therefore be used as a biomarker in interventional trials designed to reduce injury and improve neurodevelopmental outcome. (orig.)

  16. MRI Brain Tumor Segmentation and Necrosis Detection Using Adaptive Sobolev Snakes

    Nakhmani, Arie; Kikinis, Ron; Tannenbaum, Allen

    2014-01-01

    Brain tumor segmentation in brain MRI volumes is used in neurosurgical planning and illness staging. It is important to explore the tumor shape and necrosis regions at different points of time to evaluate the disease progression. We propose an algorithm for semi-automatic tumor segmentation and necrosis detection. Our algorithm consists of three parts: conversion of MRI volume to a probability space based on the on-line learned model, tumor probability density estimation, and adaptive segmentation in the probability space. We use manually selected acceptance and rejection classes on a single MRI slice to learn the background and foreground statistical models. Then, we propagate this model to all MRI slices to compute the most probable regions of the tumor. Anisotropic 3D diffusion is used to estimate the probability density. Finally, the estimated density is segmented by the Sobolev active contour (snake) algorithm to select smoothed regions of the maximum tumor probability. The segmentation approach is robust to noise and not very sensitive to the manual initialization in the volumes tested. Also, it is appropriate for low contrast imagery. The irregular necrosis regions are detected by using the outliers of the probability distribution inside the segmented region. The necrosis regions of small width are removed due to a high probability of noisy measurements. The MRI volume segmentation results obtained by our algorithm are very similar to expert manual segmentation. PMID:25302005

  17. Mapping the mouse brain with rs-fMRI: An optimized pipeline for functional network identification.

    Zerbi, Valerio; Grandjean, Joanes; Rudin, Markus; Wenderoth, Nicole

    2015-12-01

    The use of resting state fMRI (rs-fMRI) in translational research is a powerful tool to assess brain connectivity and investigate neuropathology in mouse models. However, despite encouraging initial results, the characterization of consistent and robust resting state networks in mice remains a methodological challenge. One key reason is that the quality of the measured MR signal is degraded by the presence of structural noise from non-neural sources. Notably, in the current pipeline of the Human Connectome Project, a novel approach has been introduced to clean rs-fMRI data, which involves automatic artifact component classification and data cleaning (FIX). FIX does not require any external recordings of physiology or the segmentation of CSF and white matter. In this study, we evaluated the performance of FIX for analyzing mouse rs-fMRI data. Our results showed that FIX can be easily applied to mouse datasets and detects true signals with 100% accuracy and true noise components with very high accuracy (>98%), thus reducing both within- and between-subject variability of rs-fMRI connectivity measurements. Using this improved pre-processing pipeline, maps of 23 resting state circuits in mice were identified including two networks that displayed default mode network-like topography. Hierarchical clustering grouped these neural networks into meaningful larger functional circuits. These mouse resting state networks, which are publicly available, might serve as a reference for future work using mouse models of neurological disorders.

  18. MRI in the evaluation of facial dermal fillers in normal and complicated cases

    Di Girolamo, Marco [Rome Univ. (Italy). Radiology Unit; Rome Univ. (Italy). Dept. of Radiology - Sant' Andrea Hospital; Mattei, Mauro [Rome Univ. (Italy). Radiology Unit; Signore, Alberto [Rome Univ. (Italy). Nuclear Medicine Unit; University Medical Center Groningen (Netherlands). Dept. of Nuclear Medicine and Molecular Imaging; Grippaudo, Francesca Romana [Rome Univ. (Italy). Plastic Surgery Unit

    2015-05-01

    To ascertain by MRI the presence of filler injected into facial soft tissue and characterize complications by contrast enhancement. Nineteen volunteers without complications were initially investigated to study the MRI features of facial fillers. We then studied another 26 patients with clinically diagnosed filler-related complications using contrast-enhanced MRI. TSE-T1-weighted, TSE-T2-weighted, fat-saturated TSE-T2-weighted, and TIRM axial and coronal scans were performed in all patients, and contrast-enhanced fat-suppressed TSE-T1-weighted scans were performed in complicated patients, who were then treated with antibiotics. Patients with soft-tissue enhancement and those without enhancement but who did not respond to therapy underwent skin biopsy. Fisher's exact test was used for statistical analysis. MRI identified and quantified the extent of fillers. Contrast enhancement was detected in 9/26 patients, and skin biopsy consistently showed inflammatory granulomatous reaction, whereas in 5/17 patients without contrast enhancement, biopsy showed no granulomas. Fisher's exact test showed significant correlation (p < 0.001) between subcutaneous contrast enhancement and granulomatous reaction. Cervical lymph node enlargement (longitudinal axis >10 mm) was found in 16 complicated patients (65 %; levels IA/IB/IIA/IIB). MRI is a useful non-invasive tool for anatomical localization of facial dermal filler; IV gadolinium administration is advised in complicated cases for characterization of granulomatous reaction. (orig.)

  19. Comparison between clinical, ultrasound, CT, MRI, and pathology findings in dogs presented for suspected thyroid carcinoma.

    Taeymans, Olivier; Penninck, Dominique G; Peters, Rachel M

    2013-01-01

    This study compares clinical, ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), and pathology findings in 16 prospectively, and seven retrospectively recruited dogs presented for suspected thyroid carcinoma. Of these, 17 were confirmed thyroid carcinoma, while six were initially misdiagnosed. These included four carotid body tumors, one para-esophageal abscess, and one undifferentiated squamous cell carcinoma. Thyroid carcinomas occurred in older dogs without evidence of sex predilection, and were more often unilateral. All were large, heterogeneous, moderately to strongly vascularized, and most commonly contained areas of dystrophic mineralization and/or fluid accumulations. On MRI, thyroid carcinomas appeared hyperintense compared to surrounding musculature in all imaging sequences used, while on CT they had a lower attenuation value than normal thyroid gland tissue. Histologically confirmed tumor capsule disruption with invasion of the surrounding structures was most commonly detected with MRI. Palpation was not an accurate predictor of locally invasive vs. well-encapsulated masses. Computed tomography had the highest specificity (100%) and MRI had the highest sensitivity (93%) in diagnosing thyroid carcinoma, while ultrasound had considerably lower results. We conclude that ultrasound is adequate for use as a screening tool for dogs with suspected thyroid carcinoma, but recommend either CT or MRI for preoperative diagnosis and staging.

  20. Isolated acute nontraumatic cortical subarachnoid hemorrhage: Etiologies based on MRI findings

    Cho, Eun; Kang, Myung Jin; Kim, Sang Hyeon [Dept. of Radiology, Dong-A University Medical Center, Busan (Korea, Republic of)

    2016-06-15

    The purpose of this study was to identify common underlying etiologies that may be responsible for isolated acute nontraumatic cortical subarachnoid hemorrhage (cSAH) by analysis of magnetic resonance imaging (MRI) findings of the brain. From August 2005 to February 2014, 15 cSAH patients were admitted to our institution. All patients with cSAH underwent brain MRI and magnetic resonance angiography as a part of their initial evaluation. An analysis of the patients' medical history, clinical presentations, and brain MRI findings was retrospectively performed. Among the combined pathologies that were suspected causes of cSAH, 11 patients showed acute or subacute cerebral infarctions at the ipsilateral hemisphere of cSAH on the diffusion-weighted images. Four of 11 patients had only cerebral infarction, but the other 7 had combined vasculopathy of extra- and intracranial arteries. Four of 15 patients who did not have cerebral infarction, had intracranial artery stenosis, or showed possible cerebral amyloid angiopathy, or no abnormal findings on the brain MRI. Ischemic stroke, such as cerebral infarction or vasculopathy of the extra and intracranial arteries is regarded as a common underlying etiology of the cSAH based on MRI findings.

  1. Imaging artifacts induced by electrical stimulation during conventional fMRI of the brain.

    Antal, Andrea; Bikson, Marom; Datta, Abhishek; Lafon, Belen; Dechent, Peter; Parra, Lucas C; Paulus, Walter

    2014-01-15

    Functional magnetic resonance imaging (fMRI) of brain activation during transcranial electrical stimulation is used to provide insight into the mechanisms of neuromodulation and targeting of particular brain structures. However, the passage of current through the body may interfere with the concurrent detection of blood oxygen level-dependent (BOLD) signal, which is sensitive to local magnetic fields. To test whether these currents can affect concurrent fMRI recordings we performed conventional gradient echo-planar imaging (EPI) during transcranial direct current (tDCS) and alternating current stimulation (tACS) on two post-mortem subjects. tDCS induced signals in both superficial and deep structures. The signal was specific to the electrode montage, with the strongest signal near cerebrospinal fluid (CSF) and scalp. The direction of change relative to non-stimulation reversed with tDCS stimulation polarity. For tACS there was no net effect of the MRI signal. High-resolution individualized modeling of current flow and induced static magnetic fields suggested a strong coincidence of the change EPI signal with regions of large current density and magnetic fields. These initial results indicate that (1) fMRI studies of tDCS must consider this potentially confounding interference from current flow and (2) conventional MRI imaging protocols can be potentially used to measure current flow during transcranial electrical stimulation. The optimization of current measurement and artifact correction techniques, including consideration of the underlying physics, remains to be addressed.

  2. Pseudo-progression after stereotactic radiotherapy of brain metastases: lesion analysis using MRI cine-loops.

    Wiggenraad, Ruud; Bos, Petra; Verbeek-de Kanter, Antoinette; Lycklama À Nijeholt, Geert; van Santvoort, Jan; Taphoorn, Martin; Struikmans, Henk

    2014-09-01

    Stereotactic radiotherapy (SRT) of brain metastasis can lead to lesion growth caused by radiation toxicity. The pathophysiology of this so-called pseudo-progression is poorly understood. The purpose of this study was to evaluate the use of MRI cine-loops for describing the consecutive events in this radiation induced lesion growth. Ten patients were selected from our department's database that had received SRT of brain metastases and had lesion growth caused by pseudo-progression as well as at least five follow-up MRI scans. Pre- and post SRT MRI scans were co-registered and cine-loops were made using post-gadolinium 3D T1 axial slices. The ten cine loops were discussed in a joint meeting of the authors. The use of cine-loops was superior to evaluation of separate MRI scans for interpretation of events after SRT. There was a typical lesion evolution pattern in all patients with varying time course. Initially regression of the metastases was observed, followed by an enlarging area of new contrast enhancement in the surrounding brain tissue. Analysis of consecutive MRI's using cine-loops may improve understanding of pseudo-progression. It probably represents a radiation effect in brain tissue surrounding the irradiated metastasis and not enlargement of the metastasis itself.

  3. A 4-channel 3 Tesla phased array receive coil for awake rhesus monkey fMRI and diffusion MRI experiments

    Khachaturian, Mark Haig

    2010-01-01

    Awake monkey fMRI and diffusion MRI combined with conventional neuroscience techniques has the potential to study the structural and functional neural network. The majority of monkey fMRI and diffusion MRI experiments are performed with single coils which suffer from severe EPI distortions which limit resolution. By constructing phased array coils for monkey MRI studies, gains in SNR and anatomical accuracy (i.e., reduction of EPI distortions) can be achieved using parallel imaging. The major...

  4. A novel electron gun for inline MRI-linac configurations

    Constantin, Dragoş E., E-mail: dragos.constantin@varian.com; Fahrig, Rebecca [Department of Radiology, Stanford University, Stanford, California 94305 (United States); Holloway, Lois [Liverpool and Macarthur Cancer Therapy Centres, The University of Sydney, NSW 2006 (Australia); Keall, Paul J. [Radiation Physics Laboratory, The University of Sydney, NSW 2006 (Australia)

    2014-02-15

    Purpose: This work introduces a new electron gun geometry capable of robust functioning in the presence of a high strength external magnetic field for axisymmetric magnetic resonance imaging (MRI)-linac configurations. This allows an inline MRI-linac to operate without the need to isolate the linear accelerator (linac) using a magnetic shield. This MRI-linac integration approach not only leaves the magnet homogeneity unchanged but also provides the linac flexibility to move along the magnet axis of symmetry if the source to target distance needs to be adjusted. Methods: Simple electron gun geometry modifications of a Varian 600C electron gun are considered and solved in the presence of an external magnetic field in order to determine a set of design principles for the new geometry. Based on these results, a new gun geometry is proposed and optimized in the fringe field of a 0.5 T open bore MRI magnet (GE Signa SP). A computer model for the 6 MeV Varian 600C linac is used to determine the capture efficiency of the new electron gun-linac system in the presence of the fringe field of the same MRI scanner. The behavior of the new electron gun plus the linac system is also studied in the fringe fields of two other magnets, a 1.0 T prototype open bore magnet and a 1.5 T GE Conquest scanner. Results: Simple geometrical modifications of the original electron gun geometry do not provide feasible solutions. However, these tests show that a smaller transverse cathode diameter with a flat surface and a slightly larger anode diameter could alleviate the current loss due to beam interactions with the anode in the presence of magnetic fields. Based on these findings, an initial geometry resembling a parallel plate capacitor with a hole in the anode is proposed. The optimization procedure finds a cathode-anode distance of 5 mm, a focusing electrode angle of 5°, and an anode drift tube length of 17.1 mm. Also, the linac can be displaced with ±15 cm along the axis of the 0.5 T

  5. Comparison of MRI and PET-CT in detecting the loco-regional recurrence of soft tissue sarcomas during surveillance

    Park, Sun-Young [University of Ulsan College of Medicine, Asan Medical Center, Department of Radiology and Research Institute of Radiology, 88, Olympic-ro 43-gil, Songpa-gu, Seoul (Korea, Republic of); Hallym University Sacred Heart Hospital, Department of Radiology, Anyang-si, Gyeonggi-do (Korea, Republic of); Chung, Hye Won [University of Ulsan College of Medicine, Asan Medical Center, Department of Radiology and Research Institute of Radiology, 88, Olympic-ro 43-gil, Songpa-gu, Seoul (Korea, Republic of); Chae, Sun Young [University of Ulsan College of Medicine, Asan Medical Center, Department of Nuclear Medicine, 88, Olympic-ro 43-gil, Songpa-gu, Seoul (Korea, Republic of); Lee, Jong-Seok [University of Ulsan College of Medicine, Asan Medical Center, Department of Orthopedic Surgery, 88, Olympic-ro 43-gil, Songpa-gu, Seoul (Korea, Republic of)

    2016-10-15

    To investigate the diagnostic performance of MRI and PET-CT for the detection of loco-regional recurrences after soft tissue sarcoma (STS) excision. From Dec 2003 to Aug 2014, 394 patients with STSs, who were included in the electronic patient registry for initial or repeated surgery at our hospital, were retrospectively reviewed. We identified 152 patients who underwent regular postoperative follow-ups with both MRI and PET-CT, obtained within a 3 month period of each other. We analyzed differences in the performance of MRI and PET-CT for the diagnosis of loco-regional recurrences using McNemar's test. The receiver-operating characteristic curves and calculations of the area under the curve were used. Twenty patients were found to have a loco-regional recurrence after tumor excision. For MRI and PET-CT, the sensitivities were 90.0 and 95.0 %, and the specificities 97.7 and 95.5 %, respectively, with positive predictive values of 85.7 and 76.0 % and negative predictive values of 98.5 and 99.2 %, respectively. No significant difference was detected between the sensitivities of MRI and PET-CT (p = 0.125). The area under the receiver-operating characteristic curve for PET-CT (0.952) was not significantly greater than that for MRI (0.939; p = 0.6). MRI of the area of interest is recommended for evaluation of tumor recurrence after surgical excision of STS. PET-CT was shown to be effective for detection of STS recurrence, and comparable to MRI. However, if PET-CT or MRI findings are inconclusive, the other modality may be helpful in differentiating tumor recurrence from post-therapeutic tissue change. (orig.)

  6. "MRI Stealth" robot for prostate interventions.

    Stoianovici, Dan; Song, Danny; Petrisor, Doru; Ursu, Daniel; Mazilu, Dumitru; Muntener, Michael; Mutener, Michael; Schar, Michael; Patriciu, Alexandru

    2007-01-01

    The paper reports an important achievement in MRI instrumentation, a pneumatic, fully actuated robot located within the scanner alongside the patient and operating under remote control based on the images. Previous MRI robots commonly used piezoelectric actuation limiting their compatibility. Pneumatics is an ideal choice for MRI compatibility because it is decoupled from electromagnetism, but pneumatic actuators were hardly controllable. This achievement was possible due to a recent technology breakthrough, the invention of a new type of pneumatic motor, PneuStep 1, designed for the robot reported here with uncompromised MRI compatibility, high-precision, and medical safety. MrBot is one of the "MRI stealth" robots today (the second is described in this issue by Zangos et al.). Both of these systems are also multi-imager compatible, being able to operate with the imager of choice or cross-imaging modalities. For MRI compatibility the robot is exclusively constructed of nonmagnetic and dielectric materials such as plastics, ceramics, crystals, rubbers and is electricity free. Light-based encoding is used for feedback, so that all electric components are distally located outside the imager's room. MRI robots are modern, digital medical instruments in line with advanced imaging equipment and methods. These allow for accessing patients within closed bore scanners and performing interventions under direct (in scanner) imaging feedback. MRI robots could allow e.g. to biopsy small lesions imaged with cutting edge cancer imaging methods, or precisely deploy localized therapy at cancer foci. Our robot is the first to show the feasibility of fully automated in-scanner interventions. It is customized for the prostate and operates transperineally for needle interventions. It can accommodate various needle drivers for different percutaneous procedures such as biopsy, thermal ablations, or brachytherapy. The first needle driver is customized for fully automated low

  7. Multichannel compressive sensing MRI using noiselet encoding.

    Pawar, Kamlesh; Egan, Gary; Zhang, Jingxin

    2015-01-01

    The incoherence between measurement and sparsifying transform matrices and the restricted isometry property (RIP) of measurement matrix are two of the key factors in determining the performance of compressive sensing (CS). In CS-MRI, the randomly under-sampled Fourier matrix is used as the measurement matrix and the wavelet transform is usually used as sparsifying transform matrix. However, the incoherence between the randomly under-sampled Fourier matrix and the wavelet matrix is not optimal, which can deteriorate the performance of CS-MRI. Using the mathematical result that noiselets are maximally incoherent with wavelets, this paper introduces the noiselet unitary bases as the measurement matrix to improve the incoherence and RIP in CS-MRI. Based on an empirical RIP analysis that compares the multichannel noiselet and multichannel Fourier measurement matrices in CS-MRI, we propose a multichannel compressive sensing (MCS) framework to take the advantage of multichannel data acquisition used in MRI scanners. Simulations are presented in the MCS framework to compare the performance of noiselet encoding reconstructions and Fourier encoding reconstructions at different acceleration factors. The comparisons indicate that multichannel noiselet measurement matrix has better RIP than that of its Fourier counterpart, and that noiselet encoded MCS-MRI outperforms Fourier encoded MCS-MRI in preserving image resolution and can achieve higher acceleration factors. To demonstrate the feasibility of the proposed noiselet encoding scheme, a pulse sequences with tailored spatially selective RF excitation pulses was designed and implemented on a 3T scanner to acquire the data in the noiselet domain from a phantom and a human brain. The results indicate that noislet encoding preserves image resolution better than Fouirer encoding.

  8. Sodium MRI in human heart: a review.

    Bottomley, Paul A

    2016-02-01

    This paper offers a critical review of the properties, methods and potential clinical application of sodium ((23)Na) MRI in human heart. Because the tissue sodium concentration (TSC) in heart is about ~40 µmol/g wet weight, and the (23)Na gyromagnetic ratio and sensitivity are respectively about one-quarter and one-11th of that of hydrogen ((1)H), the signal-to-noise ratio of (23)Na MRI in the heart is about one-6000th of that of conventional cardiac (1)H MRI. In addition, as a quadrupolar nucleus, (23)Na exhibits ultra-short and multi-component relaxation behavior (T1 ~ 30 ms; T2 ~ 0.5-4 ms and 12-20 ms), which requires fast, specialized, ultra-short echo-time MRI sequences, especially for quantifying TSC. Cardiac (23)Na MRI studies from 1.5 to 7 T measure a volume-weighted sum of intra- and extra-cellular components present at cytosolic concentrations of 10-15 mM and 135-150 mM in healthy tissue, respectively, at a spatial resolution of about 0.1-1 ml in 10 min or so. Currently, intra- and extra-cellular sodium cannot be unambiguously resolved without the use of potentially toxic shift reagents. Nevertheless, increases in TSC attributable to an influx of intra-cellular sodium and/or increased extra-cellular volume have been demonstrated in human myocardial infarction consistent with prior animal studies, and arguably might also be seen in future studies of ischemia and cardiomyopathies--especially those involving defects in sodium transport. While technical implementation remains a hurdle, a central question for clinical use is whether cardiac (23)Na MRI can deliver useful information unobtainable by other more convenient methods, including (1)H MRI.

  9. Multichannel compressive sensing MRI using noiselet encoding.

    Kamlesh Pawar

    Full Text Available The incoherence between measurement and sparsifying transform matrices and the restricted isometry property (RIP of measurement matrix are two of the key factors in determining the performance of compressive sensing (CS. In CS-MRI, the randomly under-sampled Fourier matrix is used as the measurement matrix and the wavelet transform is usually used as sparsifying transform matrix. However, the incoherence between the randomly under-sampled Fourier matrix and the wavelet matrix is not optimal, which can deteriorate the performance of CS-MRI. Using the mathematical result that noiselets are maximally incoherent with wavelets, this paper introduces the noiselet unitary bases as the measurement matrix to improve the incoherence and RIP in CS-MRI. Based on an empirical RIP analysis that compares the multichannel noiselet and multichannel Fourier measurement matrices in CS-MRI, we propose a multichannel compressive sensing (MCS framework to take the advantage of multichannel data acquisition used in MRI scanners. Simulations are presented in the MCS framework to compare the performance of noiselet encoding reconstructions and Fourier encoding reconstructions at different acceleration factors. The comparisons indicate that multichannel noiselet measurement matrix has better RIP than that of its Fourier counterpart, and that noiselet encoded MCS-MRI outperforms Fourier encoded MCS-MRI in preserving image resolution and can achieve higher acceleration factors. To demonstrate the feasibility of the proposed noiselet encoding scheme, a pulse sequences with tailored spatially selective RF excitation pulses was designed and implemented on a 3T scanner to acquire the data in the noiselet domain from a phantom and a human brain. The results indicate that noislet encoding preserves image resolution better than Fouirer encoding.

  10. MRI findings and spreading patterns of necrotizing external otitis: Is a poor outcome predictable?

    Kwon, B.J. [Department of Radiology, Seoul National University College of Medicine, Seoul (Korea, Republic of); Han, M.H. [Department of Radiology, Seoul National University College of Medicine, Seoul (Korea, Republic of) and Clinical Research Institute, Seoul National University Hospital, Seoul (Korea, Republic of) and Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul (Korea, Republic of)]. E-mail: hanmh@radcom.snu.ac.kr; Oh, S.H. [Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University College of Medicine, Seoul (Korea, Republic of); Song, J.J. [Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University College of Medicine, Seoul (Korea, Republic of); Chang, K.-H. [Department of Radiology, Seoul National University College of Medicine, Seoul (Korea, Republic of); Clinical Research Institute, Seoul National University Hospital, Seoul (Korea, Republic of); Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul (Korea, Republic of)

    2006-06-15

    AIM: To evaluate spreading patterns of necrotizing external otitis (NEO) by magnetic resonance imaging (MRI) and to identify spreading patterns related to a poor outcome. MATERIALS AND METHODS: Fourteen patients with NEO were divided into good and poor outcome groups according to their final clinical outcomes. Initial MRI images were retrospectively reviewed for regional abnormalities, and follow-up MRI images were reviewed for ICA flow void abnormality and for the following five spreading patterns: medial, crossed, anterior, intracranial, and combined. The frequencies of the abnormal flow void or spreading patterns were compared between the good and poor response groups. RESULTS: Seven (50%) and seven (50%) patients were respectively allocated to the good and poor outcome groups. Retrocondylar fat infiltration was the most commonest finding on initial MRI images (93%). The frequencies of the abnormal flow void and spreading patterns in the good and poor groups, respectively, were: abnormal flow void, 0 and four (57%); anterior, two (29%) and three (43%); medial, six (86%) and seven (100%); crossed, six (86%) and seven (100%); intracranial middle cranial fossa, one (14%) and four (57%); intracranial posterior cranial fossa, four (57%) and six (86%); intracranial foramen magnum, one (14%) and six (86%). CONCLUSIONS: NEO almost always involves the retrocondylar fat and spreads via various pathways to extracranial or intracranial spaces. The presence of an abnormal flow void and intracranial dural enhancement, particularly in the middle cranial fossa and foramen magnum, may indicate a poor prognosis.

  11. Local 2D Particle-in-cell simulations of the collisionless MRI

    Riquelme, Mario A; Sharma, Prateek; Spitkovsky, Anatoly

    2012-01-01

    The magnetorotational instability (MRI) is a crucial mechanism of angular momentum transport in a variety of astrophysical accretion disks. In systems accreting at well below the Eddington rate, such as the central black hole in the Milky Way (Sgr A*), the rate of Coulomb collisions between particles is very small, making the disk evolve essentially as a collisionless plasma. We present a nonlinear study of the collisionless MRI using first-principles particle-in-cell (PIC) plasma simulations. In this initial study we focus on local two-dimensional (axisymmetric) simulations, deferring more realistic three-dimensional simulations to future work. For simulations with net vertical magnetic flux, the MRI continuously amplifies the magnetic field until the Alfv\\'en velocity, v_A, is comparable to the speed of light, c (independent of the initial value of v_A/c). This is consistent with the lack of saturation of MRI channel modes in analogous axisymmetric MHD simulations. The amplification of the magnetic field by...

  12. 乳腺疾病的 MRI 诊断%MRI dia gnosis the breast diseases

    杨正军; 郭周中; 赵双全

    2012-01-01

      Objective:To investigate the application value of MRI in the diagno sis of breast diseases.Methods: The clinical data of 126 cases of patients with breast disease confirmed by surgical biopsy was analyzed retrospectively.The MRI findings of breast lesions were analyzed.The MRI features of benign and malignant lesions were compared.Results 77 cases with benign lesions were eccentric strengthening, while 49 cases with malignant lesions being concentric strengthening. Besides,the contrast of both enhanced MRI and time intensity curve type between benign and malignant lesions,which had significant differences (P ﹤ 0.05,P ﹤ 0.01).Conclusions MRI imaging examination has a high clinical value in the differential diagnosis of benign and malignant breast lesions.%  目的探讨 MRI 对乳腺疾病的临床应用价值.方法回顾性分析126例经手术病理证实的乳腺疾病患者病例资料,分析乳腺病变的 MRI 检查结果,对比良、恶性病变的 MRI 特点.结果126例患者中,良性病变者77例为离心性强化,恶性病变者49例为向心性强化,且良恶性病变的 MRI 增强对比及时间强度曲线分型对比均具有显著性差异(P ﹤0.05,P ﹤0.01).结论 MRI 影像学检查技术在鉴别诊断乳腺良恶性病变时具有很高的临床价值.

  13. MRI & MR SPECTROSCOPIC EVALUATION OF PROSTATIC CARCINOMA

    Rupak

    2015-09-01

    Full Text Available BACKGROUND : Prostate cancer is the most common malignancy among men more than fifty years of age (Cancer foundation of India. Imaging may help in clarifying several important issues in localized prostate cancer. MRI provides the best depiction of the contours of the prostate as well as its internal zonal anatomy. Recent evidence suggests that multi - parametric MRI could improve the accuracy of diagnostic assessment in prostate cancer. In addition, MRI also allows functional assessment with techniques such as diffusion - weighted MRI (DWI, MR spectroscopy (MRS, and dynamic contrast enhanced MRI (DCE - MRI. Strong opinions are held about the need for endorectal coil imaging. Endorectal coils provide large gains in signal with reductions in noise, most noticeably at 1.5 T; however, endorectal coils are uncomfortable and expensive. At 3 T, the need for endorectal coils has been debated. Clearly, the highest - quality MRI results from the combined use of endorectal coils and phased array body coils at 3 T. Prostate cancer is associated with proportionately lower levels of citrate and higher levels of choline and creatine than are seen in benign prostatic hyperplasia (BPH or in normal prostate tissu e. This difference can be detected by magnetic resonance spectroscopic imaging (MRSI. MRSI uses a strong magnetic field to obtain metabolic information (spectra that identifies the relative concentrations of various metabolites in the cell cytoplasm and the extracellular space. This technique can identify metabolic differences in prostate tissue (BPH, prostate cance r, and normal prostate tissue. AIM: To evaluate the role of MRI and MR Spectroscopy in the diagnosis of prostatic carcinoma by pelvic phased array coil in the detection of prostatic carcinoma in men with Prostatomegaly & elevated PSA levels and establishing statistical analysis of the same. METHOD: A prospective study of minimum 50 consecutive cases with Prostatomegaly & raised PSA levels

  14. 3-D Dynamics of Interactions between Stellar Winds and the Interstellar Medium as Seen by AKARI and Spitzer

    Ueta, Toshiya; Yamamura, Issei; Stencel, Robert E; Nakada, Yoshikazu; Matsuura, Mikako; Ita, Yoshifusa; Tanabe, Toshihiko; Fukushi, Hinako; Matsunaga, Noriyuki; Mito, Hiroyuki; Speck, Angela K

    2009-01-01

    Recent far-infrared mapping of mass-losing stars by the AKARI Infrared Astronomy Satellite and Spitzer Space Telescope have suggested that far-infrared bow shock structures are probably ubiquitous around these mass-losing stars, especially when these stars have high proper motion. Higher spatial resolution data of such far-infrared bow shocks now allow detailed fitting to yield the orientation of the bow shock cone with respect to the heliocentric space motion vector of the central star, using the analytical solution for these bow shocks under the assumption of momentum conservation across a physically thin interface between the stellar winds and interstellar medium (ISM). This fitting analysis of the observed bow shock structure would enable determination of the ambient ISM flow vector, founding a new technique to probe the 3-D ISM dynamics that are local to these interacting systems. In this review, we will demonstrate this new technique for three particular cases, Betelgeuse, R Hydrae, and R Cassiopeiae.

  15. Mobile Biplane X-Ray Imaging System for Measuring 3D Dynamic Joint Motion During Overground Gait.

    Guan, Shanyuanye; Gray, Hans A; Keynejad, Farzad; Pandy, Marcus G

    2016-01-01

    Most X-ray fluoroscopy systems are stationary and impose restrictions on the measurement of dynamic joint motion; for example, knee-joint kinematics during gait is usually measured with the subject ambulating on a treadmill. We developed a computer-controlled, mobile, biplane, X-ray fluoroscopy system to track human body movement for high-speed imaging of 3D joint motion during overground gait. A robotic gantry mechanism translates the two X-ray units alongside the subject, tracking and imaging the joint of interest as the subject moves. The main aim of the present study was to determine the accuracy with which the mobile imaging system measures 3D knee-joint kinematics during walking. In vitro experiments were performed to measure the relative positions of the tibia and femur in an intact human cadaver knee and of the tibial and femoral components of a total knee arthroplasty (TKA) implant during simulated overground gait. Accuracy was determined by calculating mean, standard deviation and root-mean-squared errors from differences between kinematic measurements obtained using volumetric models of the bones and TKA components and reference measurements obtained from metal beads embedded in the bones. Measurement accuracy was enhanced by the ability to track and image the joint concurrently. Maximum root-mean-squared errors were 0.33 mm and 0.65° for translations and rotations of the TKA knee and 0.78 mm and 0.77° for translations and rotations of the intact knee, which are comparable to results reported for treadmill walking using stationary biplane systems. System capability for in vivo joint motion measurement was also demonstrated for overground gait.

  16. Quantifying transient 3D dynamical phenomena of single mRNA particles in live yeast cell measurements.

    Calderon, Christopher P; Thompson, Michael A; Casolari, Jason M; Paffenroth, Randy C; Moerner, W E

    2013-12-12

    Single-particle tracking (SPT) has been extensively used to obtain information about diffusion and directed motion in a wide range of biological applications. Recently, new methods have appeared for obtaining precise (10s of nm) spatial information in three dimensions (3D) with high temporal resolution (measurements obtained every 4 ms), which promise to more accurately sense the true dynamical behavior in the natural 3D cellular environment. Despite the quantitative 3D tracking information, the range of mathematical methods for extracting information about the underlying system has been limited mostly to mean-squared displacement analysis and other techniques not accounting for complex 3D kinetic interactions. There is a great need for new analysis tools aiming to more fully extract the biological information content from in vivo SPT measurements. High-resolution SPT experimental data has enormous potential to objectively scrutinize various proposed mechanistic schemes arising from theoretical biophysics and cell biology. At the same time, methods for rigorously checking the statistical consistency of both model assumptions and estimated parameters against observed experimental data (i.e., goodness-of-fit tests) have not received great attention. We demonstrate methods enabling (1) estimation of the parameters of 3D stochastic differential equation (SDE) models of the underlying dynamics given only one trajectory; and (2) construction of hypothesis tests checking the consistency of the fitted model with the observed trajectory so that extracted parameters are not overinterpreted (the tools are applicable to linear or nonlinear SDEs calibrated from nonstationary time series data). The approach is demonstrated on high-resolution 3D trajectories of single ARG3 mRNA particles in yeast cells in order to show the power of the methods in detecting signatures of transient directed transport. The methods presented are generally relevant to a wide variety of 2D and 3D SPT tracking applications.

  17. Radionuclide transport and uptake in coastal aquatic ecosystems - a comparison of a 3D dynamic model and a compartment model

    Konovalenko, L.; Bradshaw, C. [The Department of Ecology, Environment and Plant Sciences Stockholm University (Sweden); Erichsen, A.C.; Moehlenberg, F. [Ecological and Environmental Department DHI (Sweden); Kautsky, U. [Swedish Nuclear Fuel and Waste Management Co - SKB (Sweden)

    2014-07-01

    In safety assessments of underground radioactive waste repositories, understanding the fate of radionuclides in ecosystems is necessary. Here, two mechanistic models (K- and D- model) describing the fate of radionuclides released into a Baltic Sea bay were compared. Both are based on ecosystem models that simulate the cycling of organic matter. Parallel to adsorption, transfer of radionuclides is linked to flows of organic matter (carbon) in food chains. Despite differences in temporal resolution, biological state variables and partition coefficients, the accumulation of Th-230, Cs-135 and Ni-59 in biological compartments was comparable between the models and with site measurements. Both models provided confidence limits for their modeled concentration ratios, an improvement over models that only estimate mean values. The D-model enables estimates at high spatio-temporal resolution. The K-model being coarser but faster, allows estimates centuries ahead. Future developments could integrate the two models to take full advantage of their respective strengths. Document available in abstract form only. (authors)

  18. {sup 23}Na-MRI of recurrent glioblastoma multiforme after intraoperative radiotherapy: technical note

    Haneder, Stefan; Buesing, Karen A.; Schoenberg, Stefan O.; Ong, Melissa M. [Heidelberg University, Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Mannheim (Germany); Giordano, Frank A.; Wenz, Frederik [University of Heidelberg, Department of Radiation Oncology, University Medical Center Mannheim, Mannheim (Germany); Konstandin, Simon; Schad, Lothar R. [Heidelberg University, Computer Assisted Clinical Medicine, Mannheim (Germany); Brehmer, Stefanie; Schmiedek, Peter [Heidelberg University, Department of Neurosurgery, University Medical Center Mannheim, Mannheim (Germany)

    2015-03-01

    We report the first case of an intraoperative radiotherapy (IORT) in a patient with recurrent glioblastoma multiforme (GBM) who was followed up with a novel magnetic resonance imaging (MRI) method - {sup 23}Na-MRI - in comparison to a standard contrast-enhanced {sup 1}H-MRI and {sup 18}F-FET-PET. A 56-year-old female patient with diagnosed GBM in July 2012 underwent tumor resection, radiochemotherapy, and three cycles of chemotherapy. After a relapse, 6 months after the initial diagnosis, an IORT was recommended which was performed in March 2013 using the INTRABEAM system (Carl Zeiss Meditec AG, Germany) with a 3-cm applicator and a surface dose of 20 Gy. Early post-operative contrast-enhanced and 1-month follow-up {sup 1}H-MRI and a {sup 18}F-FET-PET were performed. In addition, an IRB-approved {sup 23}Na-MRI was performed on a 3.0-T MR scanner (MAGNETOM TimTrio, Siemens Healthcare, Germany). After re-surgery and IORT in March 2013, only a faint contrast enhancement but considerable surrounding edema was visible at the medio-posterior resection margins. In April 2013, new and progressive contrast enhancement, edema, {sup 23}Na content, and increased uptake in the {sup 18}F-FET-PET were visible, indicating tumor recurrence. Increased sodium content within the area of contrast enhancement was found in the {sup 23}Na-MRI, but also exceeding this area, very similar to the increased uptake depicted in the {sup 18}F-FET-PET. The clearly delineable zone of edema in both examinations exhibits a lower {sup 23}Na content compared to areas with suspected proliferating tumor tissue. {sup 23}Na-MRI provided similar information in the suspicious area compared to {sup 18}F-FET-PET, exceeding conventional {sup 1}H-MRI. Still, {sup 23}Na-MRI remains an investigational technique, which is worth to be further evaluated. (orig.)

  19. Localization of spinal tumors by MRI

    Takahashi, Mutsumasa; Sakamoto, Yuji; Kojima, Ryutaro; Yamashita, Yasuyuki; Bussaka, Hiromasa

    1989-02-01

    Exact localization of the spinal tumors is particularly important for differential diagnosis and surgery. Therefore, it was attempted to evauate the diagnostic accuracy of MRI in localizing the spinal tumors exactly. Nineteen cases of spinal cord tumors, being localized in the intradural extramedullary, extradural and both intradural and extradural spaces, were studied with MRI. Intradural extramedullary tumors showed small CSF spaces just below and above the tumor which were demonstrated as CSF intensity on T1 and T2 weighted images. Although extradural tumors did not show CSF spaces, there was extradural sign or dural density between the tumor and the spinal cord. Intradural and extradural tumors were outlined as having both characteristics. Signal intensities of the spinal tumors were not characteristic for specific histology. Gd-DTPA was quite useful for accurate localization of the tumors. In comparison with myelography, MRI was superior to myelography in extradural tumors and equally useful for intradural and extradural tumors, but it was less diagnostic in intradural extramedullary tumors. In general, MRI was quite useful in localizing the spinal tumors exactly and the accuracy of MRI was quite high. In the near future this technique will replace myelography and other radiologic methods.

  20. Low Field Squid MRI Devices, Components and Methods

    Penanen, Konstantin I. (Inventor); Eom, Byeong H. (Inventor); Hahn, Inseob (Inventor)

    2014-01-01

    Low field SQUID MRI devices, components and methods are disclosed. They include a portable low field (SQUID)-based MRI instrument and a portable low field SQUID-based MRI system to be operated under a bed where a subject is adapted to be located. Also disclosed is a method of distributing wires on an image encoding coil system adapted to be used with an NMR or MRI device for analyzing a sample or subject and a second order superconducting gradiometer adapted to be used with a low field SQUID-based MRI device as a sensing component for an MRI signal related to a subject or sample.

  1. Early diagnosis and follow-up of aortitis with [{sup 18}F]FDG PET and MRI

    Meller, J.; Siefker, U.; Sahlmann, C.O.; Lehmann, K.; Conrad, M. [Department of Nuclear Medicine, Georg August University, Robert Koch-Strasse 40, 37075, Goettingen (Germany); Strutz, F.; Scheel, A. [Department of Nephrology and Rheumatology, Georg August University, Goettingen (Germany); Vosshenrich, R. [Department of Radiology, Georg August University, Goettingen (Germany)

    2003-05-01

    The aim of this prospective study was to compare fluorine-18 fluorodeoxyglucose ([{sup 18}F]FDG) positron emission tomography (PET) with magnetic resonance imaging (MRI) in patients with early aortitis, at the time of initial diagnosis and during immunosuppressive therapy. The study population consisted of 15 patients (nine females and six males; median age 62 years, range 26-76 years) who presented with fever of unknown origin or an elevated erythrocyte sedimentation rate or elevated C-reactive protein and who showed pathological aortic [{sup 18}F]FDG uptake. Fourteen of these patients had features of early giant cell arteritis (GCA), while one had features of early Takayasu arteritis. During follow-up, seven PET scans were performed in six patients with GCA 4-30 months (median 19 months) after starting immunosuppressive medication. The results of [{sup 18}F]FDG imaging were compared with the results of MRI at initial evaluation and during follow-up and with the clinical findings. At baseline, abnormal [{sup 18}F]FDG uptake was present in 59/104 (56%) of the vascular regions studied in 15 patients. Seven follow-up PET studies were performed in six patients. Of 30 regions with initial pathological uptake in these patients, 24 (80%) showed normalisation of uptake during follow-up. Normalisation of [{sup 18}F]FDG uptake correlated with clinical improvement and with normalisation of the laboratory findings. All except one of the patients with positive aortic [{sup 18}F]FDG uptake were investigated with MRI and MRA. Thirteen of these 14 patients showed inflammation in at least one vascular region. Of 76 vascular regions studied, 41 (53%) showed vasculitis on MRI. Of 76 vascular regions studied with both PET and MRI, 47 were concordantly positive or negative on both modalities, 11 were positive on MRI only and 18 were positive on PET only. MRI was performed during follow-up in six patients: of 17 regions with inflammatory changes, 15 regions remained unchanged and two

  2. Ictal EEG/fMRI study of vertiginous seizures.

    Morano, Alessandra; Carnì, Marco; Casciato, Sara; Vaudano, Anna Elisabetta; Fattouch, Jinane; Fanella, Martina; Albini, Mariarita; Basili, Luca Manfredi; Lucignani, Giulia; Scapeccia, Marco; Tomassi, Regina; Di Castro, Elisabetta; Colonnese, Claudio; Giallonardo, Anna Teresa; Di Bonaventura, Carlo

    2017-03-01

    Vertigo and dizziness are extremely common complaints, related to either peripheral or central nervous system disorders. Among the latter, epilepsy has to be taken into consideration: indeed, vertigo may be part of the initial aura of a focal epileptic seizure in association with other signs/symptoms, or represent the only ictal manifestation, a rare phenomenon known as "vertiginous" or "vestibular" seizure. These ictal symptoms are usually related to a discharge arising from/involving temporal or parietal areas, which are supposed to be a crucial component of the so-called "vestibular cortex". In this paper, we describe three patients suffering from drug-resistant focal epilepsy, symptomatic of malformations of cortical development or perinatal hypoxic/ischemic lesions located in the posterior regions, who presented clusters of vertiginous seizures. The high recurrence rate of such events, recorded during video-EEG monitoring sessions, offered the opportunity to perform an ictal EEG/fMRI study to identify seizure-related hemodynamic changes. The ictal EEG/fMRI revealed the main activation clusters in the temporo-parieto-occipital regions, which are widely recognized to be involved in the processing of vestibular information. Interestingly, ictal deactivation was also detected in the ipsilateral cerebellar hemisphere, suggesting the ictal involvement of cortical-subcortical structures known to be part of the vestibular integration network.

  3. Modified Gadonanotubes as a Promising Novel MRI Contrasting Agent

    Rouzbeh Jahanbakhsh

    2013-07-01

    Full Text Available Background and purpose of the study:Carbon nanotubes (CNTs are emerging drug and imaging carrier systems which show significant versatility. One of the extraordinary characteristics of CNTs as Magnetic Resonance Imaging (MRI contrasting agent is the extremely large proton relaxivities when loaded with gadolinium ion (Gdn3+ clusters.Methods:In this study equated Gdn3+ clusters were loaded in the sidewall defects of oxidized multiwalled (MW CNTs. The amount of loaded gadolinium ion into the MWCNTs was quantified by inductively coupled plasma (ICP method. To improve water solubility and biocompatibility of the system, the complexes were functionalized using diamine-terminated oligomeric poly (ethylene glycol via a thermal reaction method.Results:Gdn3+ loaded PEGylated oxidized CNTs (Gdn3+@CNTs-PEG is freely soluble in water and stable in phosphate buffer saline having particle size of about 200 nm. Transmission electron microscopy (TEM images clearly showed formation of PEGylated CNTs. MRI analysis showed that the prepared solution represents 10% more signal intensity even in half concentration of Gd3+ in comparison with commerciality available contrasting agent Magnevist®. In addition hydrophilic layer of PEG at the surface of CNTs could prepare stealth nanoparticles to escape RES.Conclusion:It was shown that Gdn3+@CNTs-PEG was capable to accumulate in tumors through enhanced permeability and retention effect. Moreover this system has a potential for early detection of diseases or tumors at the initial stages.

  4. A heuristic model for MRI turbulent stresses in Hall MHD

    Lingam, M

    2016-01-01

    Although the Shakura-Sunyaev $\\alpha$ viscosity prescription has been highly successful in characterizing myriad astrophysical environments, it has proven to be partly inadequate in modelling turbulent stresses driven by the MRI. Hence, we adopt the approach employed by \\citet{GIO03}, but in the context of Hall magnetohydrodynamics (MHD), to study MRI turbulence. We utilize the exact evolution equations for the stresses, and the non-linear terms are closed through the invocation of dimensional analysis and physical considerations. We demonstrate that the inclusion of the Hall term leads to non-trivial results, including the modification of the Reynolds and Maxwell stresses, as well as the (asymptotic) non-equipartition between the kinetic and magnetic energies; the latter issue is also addressed via the analysis of non-linear waves. The asymptotic ratio of the kinetic and magnetic energies is shown to be \\emph{independent} of the choice of initial conditions, but it is governed by the \\emph{Hall parameter}. W...

  5. MRI in human immunodeficiency virus-associated cerebral vasculitis

    Berkefeld, J.; Lanfermann, H. [Frankfurt Univ. (Germany). Abt. fuer Neuroradiologie; Enzensberger, W. [Klinik fuer Neurologie, Klinikum der Johann Wolfgang Goethe-Univ. Frankfurt am Main (Germany)

    2000-07-01

    Cerebral ischaemia caused by inflammatory vasculopathies has been described as complication of human immunodeficiency virus (HIV) infection. Imaging studies have shown ischaemic lesions and changes of the vascular lumen, but did not allow demonstration of abnormalities within the vessel wall itself. Two HIV-infected men presented with symptoms of a transient ischaemic attack. Initial MRI of the first showed no infarct; in the second two small lacunar lesions were detected. In both cases, multiplanar 3-mm slice contrast-enhanced T1-weighted images showed aneurysmal dilatation, with thickening and contrast enhancement of the wall of the internal carotid and middle cerebral (MCA) arteries. These findings were interpreted as indicating cerebral vasculitis. In the first patient the vasculopathy progressed to carotid artery occlusion, and he developed an infarct in the MCA territory, but then remained neurologically stable. In the second patient varicella zoster virus (VZV) infection was the probable cause of vasculitis. The clinical deficits and vasculitic MRI changes regressed with antiviral and immunosuppressive therapy. (orig.)

  6. STEREO/SECCHI Stereoscopic Observations Constraining the Initiation of Polar Coronal Jets

    Patsourakos, S; Vourlidas, A; Antiochos, S K; Wuelser, J P

    2008-01-01

    We report on the first stereoscopic observations of polar coronal jets made by the EUVI/SECCHI imagers on board the twin STEREO spacecraft. The significantly separated viewpoints ($\\sim$ 11$^\\circ$) allowed us to infer the 3D dynamics and morphology of a well-defined EUV coronal jet for the first time. Triangulations of the jet's location in simultaneous image pairs led to the true 3D position and thereby its kinematics. Initially the jet ascends slowly at $\\approx$10-20 $\\mathrm{{km} {s}^{-1}}$ and then, after an apparent 'jump' takes place, it accelerates impulsively to velocities exceeding 300 $\\mathrm{{km} {s}^{-1}}$ with accelerations exceeding the solar gravity. Helical structure is the most important geometrical feature of the jet which shows evidence of untwisting. The jet structure appears strikingly different from each of the two STEREO viewpoints: face-on in the one viewpoint and edge-on in the other. This provides conclusive evidence that the observed helical structure is real and is not resulting...

  7. Acute encephalitis associated with measles: MRI features

    Lee, K.Y.; Cho, W.H.; Kim, S.H. [Department of Radiology, Sanggye Paik Hospital, Inje University, 760-1 Sanggye-7 dong, Nowon-gu, Seoul 139707 (Korea); Kim, H.D. [Department of Paediatrics, Sanggye Paik Hospital, Inje University, 760-1 Sanggye-7 dong, Nowon-gu, Seoul 139707 (Korea); Kim, I.O. [Department of Radiology, Seoul National University Hospital, 28, Yongon-dong, Chongno-gu, Seoul 110744 (Korea)

    2003-02-01

    We document the MRI features in six patients aged 5-14 years with acute encephalitis following measles. The diagnosis was made on a characteristic morbiliform rash and detection of specific IgM and IgG antibodies. The symptoms of encephalitis occurred 1-11 days after the appearance of the rash. All patients underwent MRI within 1-4 days of the onset of neurological symptoms. Diffusion weighted images (DWI) were obtained in three patients. In all patients, T2-weighted images showed widely distributed, multifocal high signal in both cerebral hemispheres with swelling of the cortex, with bilateral, symmetrical involvement of the putamen and caudate nucleus. The lesions had showed low apparent diffusion coefficients. Three patients showed subacute gyriform haemorrhage, and asymmetrical gyriform contrast enhancement on follow-up MRI. (orig.)

  8. On clustering fMRI time series

    Goutte, Cyril; Toft, Peter Aundal; Rostrup, E.

    1999-01-01

    Analysis of fMRI time series is often performed by extracting one or more parameters for the individual voxels. Methods based, e.g., on various statistical tests are then used to yield parameters corresponding to probability of activation or activation strength. However, these methods do not indi...... between the activation stimulus and the fMRI signal. We present two different clustering algorithms and use them to identify regions of similar activations in an fMRI experiment involving a visual stimulus....... not indicate whether sets of voxels are activated in a similar way or in different ways. Typically, delays between two activated signals are not identified. In this article, we use clustering methods to detect similarities in activation between voxels. We employ a novel metric that measures the similarity...

  9. MRI Findings of Rectal Submucosal Tumors

    Kim, Hon Soul; Kim, Joo Hee; Lim, Joon Seok; Choi, Jin Young; Chung, Yong Eun; Park, Mi Suk; Kim, Myeong Jin; Kim, Ki Whang; Kim, Sang Kyum [Yonsei University Health System, Seoul (Korea, Republic of)

    2011-08-15

    Rectal submucosal lesions encompass a wide variety of benign and malignant tumors involving the rectum. With optical colonoscopy, any mass-like protrusion covered by normal mucosa, whether the underlying process is intramural or extramural in origin, may be reported as a submucosal lesion. Whereas the assessment of submucosal lesions may be limited with performing optical colonoscopy, cross-sectional imaging such as CT, transrectal ultrasonography and MRI allows the evaluation of perirectal tissues and pelvic organs in addition to the entire thickness of the rectum, and so this is advantageous for the assessment of rectal submucosal tumors. Among these, MRI is the best investigative modality for soft tissue characterization. Therefore, knowledge of the MRI features of rectal submucosal tumors can help achieve accurate preoperative diagnoses and facilitate the appropriate management.

  10. MRI findings in the painful hemiplegic shoulder

    Tavora, D.G.F., E-mail: danielgurgel@sarah.b [Department of Radiology, Sarah Network of Hospitals for Rehabilitation, Fortaleza (Brazil); Gama, R.L.; Bomfim, R.C. [Department of Radiology, Sarah Network of Hospitals for Rehabilitation, Fortaleza (Brazil); Nakayama, M. [Department of Radiology, Federal University of Grande Dourados, Dourados (Brazil); Silva, C.E.P. [Department of Statistics, Sarah Network of Hospitals for Rehabilitation, Fortaleza (Brazil)

    2010-10-15

    Aim: To evaluate the magnetic resonance imaging (MRI) findings in painful hemiplegic shoulder (PHS) in hemiplegic post-stroke patients. Materials and methods: Patients with hemiplegia following their first cerebrovascular accident who were admitted to the Sarah Network of Hospitals for Rehabilitation were studied. Forty-five patients with pain in the hemiplegic shoulder and 23 post-stroke patients without shoulder pain were investigated. MRI and radiographic findings of the hemiplegic and contralateral asymptomatic shoulders were evaluated. Results: Some MRI findings were more frequent in PHS group, including synovial capsule thickening, synovial capsule enhancement, and enhancement in the rotator cuff interval. Conclusions: Adhesive capsulitis was found to be a possible cause of PHS.

  11. MRI tracheomalacia (TM) assessment in pediatric patients

    Ciet, P.; Wielopolski, P.; Lever, S.

    Purpose: TM is an excessive narrowing of the intrathoracic part of the trachea. TM is a common congenital pediatric anomaly, but it’s often not recognized due to its unspecific clinical presentation. The aims of our study are: 1) to develop cine-MRI sequences to visualize central airways in static...... spirometry controlled breathing maneuvers (peak flow and coughing) using a MRI compatible spirometer. “Static” 13-second breath-hold scans covering the entire thoracic region were acquired at end-inspiration and end-expiration using a 3D GRE with TR/TE=1.2/0.5 ms, alpha = 2, sagittal isotropic volume (2.8) x...... breathing maneuvers. Images of central airways during static and dynamic conditions were acquired and could be analyzed. Three out of the 8 children had a TM just above the carina during forced expiration, confirmed by bronchoscopy. Conclusion: This pilot study shows that Dynamic-MRI is feasible...

  12. MRI in Leber's hereditary optic neuropathy

    Matthews, Lucy; Enzinger, Christian; Fazekas, Franz

    2015-01-01

    mechanism involving mitochondrial dysfunction. OBJECTIVE: The primary aim was to define MRI features of LMS and LHON, and to assess the proportions of individuals displaying features typical of MS. Secondarily, we investigated the effect of gender on the risk of developing white matter lesions...... in the context of LHON. METHODS: A blinded standardised review of conventional brain MRIs of 30 patients with MS, 31 patients with LHON and 11 patients with LMS was conducted by three independent experts in the field. MS-like MRI features were assessed. RESULTS: All patients with LMS and 26% of patients...... with LHON had white matter lesions. Of these, all patients with LMS and 25% with LHON were found to have an MRI appearance typical of MS. Female patients with LHON had a significantly greater risk of having white matter lesions consistent with MS compared with male patients (relative risk 8.3). CONCLUSIONS...

  13. Monkey cortex through fMRI glasses.

    Vanduffel, Wim; Zhu, Qi; Orban, Guy A

    2014-08-06

    In 1998 several groups reported the feasibility of fMRI experiments in monkeys, with the goal to bridge the gap between invasive nonhuman primate studies and human functional imaging. These studies yielded critical insights in the neuronal underpinnings of the BOLD signal. Furthermore, the technology has been successful in guiding electrophysiological recordings and identifying focal perturbation targets. Finally, invaluable information was obtained concerning human brain evolution. We here provide a comprehensive overview of awake monkey fMRI studies mainly confined to the visual system. We review the latest insights about the topographic organization of monkey visual cortex and discuss the spatial relationships between retinotopy and category- and feature-selective clusters. We briefly discuss the functional layout of parietal and frontal cortex and continue with a summary of some fascinating functional and effective connectivity studies. Finally, we review recent comparative fMRI experiments and speculate about the future of nonhuman primate imaging.

  14. Dynamic MRI study for breast tumors

    Seki, Tsuneaki (Kyorin Univ., Mitaka, Tokyo (Japan). School of Medicine)

    1990-10-01

    Application of MRI for diagnosis of breast tumors was retrospectively examined in 103 consecutive cases. Contrast enhancement, mostly by dynamic study, was performed in 83 cases using Gd-DTPA and 0.5 T superconductive apparatus. Results were compared to those of mammography and sonography. On dynamic study, carcinoma showed abrupt rise of signal intensity with clear-cut peak formation in early phase, while benign fibroadenoma showed slow rise of signal intensity and prolonged enhancement without peak formation. In 12 of 33 carcinomas (33%), peripheral ring enhancement was noted reflecting vascular stroma of histologic sections. All fibroadenomas showed homogenous enhancement without peripheral ring. In MRI, sensitivity, specificity, and accuracy were 86%, 96%, 91%. In mammography 82%, 95%, 87% and in ultrasonography 91%, 95%, 93%. Although MRI should not be regarded as routine diagnostic procedure because of expense and limited availability, it may afford useful additional information when standard mammographic findings are not conclusive. (author).

  15. MRI features of tuberculosis of the knee

    Sanghvi, Darshana A.; Iyer, Veena R.; Deshmukh, Tejaswini; Hoskote, Sumedh S. [Seth GS Medical College and KEM Hospital, Department of Radiology, Mumbai (India)

    2009-03-15

    The objective of this study was to describe the magnetic resonance imaging (MRI) features of tuberculosis (TB) of the knee joint. The MRI features in 15 patients with TB of the knee, as confirmed by histology of the biopsied joint synovium, were reviewed retrospectively. The images were assessed for intra-articular and peri-articular abnormalities. All patients had florid synovial proliferation. The proliferating synovium showed intermediate to low T2 signal intensity. In the patients who were administered intravenous contrast, the hypertrophic synovium was intensely enhancing. Marrow edema (n = 9), osteomyelitis (n = 4), cortical erosions (n = 5), myositis (n = 6), cellulitis (n = 2), abscesses (n = 3), and skin ulceration/sinus formation (n = 2) were seen in the adjacent bone and soft tissue. Synovial proliferation associated with tuberculous arthritis is typically hypointense on T2-weighted images. This appearance, in conjunction with other peri-articular MRI features described, can help in distinguishing TB arthritis from other proliferating synovial arthropathies. (orig.)

  16. MRI of lumbar trunk muscles in patients with Parkinson's disease and camptocormia.

    Margraf, N G; Rohr, A; Granert, O; Hampel, J; Drews, A; Deuschl, G

    2015-07-01

    Camptocormia in Parkinson's disease (PD) is an axial postural disorder usually accompanied by histopathological changes in the paravertebral muscles of unknown etiology. The diagnostic potential of magnetic resonance imaging (MRI) of back muscles in camptocormia has not been systematically assessed. Our objective was to characterize pathological muscle changes with MRI and to develop radiological criteria for camptocormia. The criteria edema, swelling and fatty degeneration in 20 idiopathic PD patients with camptocormia were assessed using MRI (T1w and short tau inversion recovery (STIR) sequences) of the lumbar trunk muscles and compared with 20 group-matched PD patients without camptocormia. Edema and fatty degeneration of the paravertebral muscles were significantly more frequent in camptocormia. Edema correlated negatively and fatty degeneration positively with the duration of camptocormia and not PD. Swelling of the paravertebral muscles, edema and swelling of the quadratus lumborum muscle and rare edema of the psoas muscle were only found in camptocormia patients. In this case-control study the defined MRI criteria distinguish the group of PD patients with camptocormia versus those without. Our findings suggest dynamic changes in the MRI signals over time in the paravertebral muscles: edema and swelling are found initially, followed by fatty atrophic degeneration 2-3 years after the beginning of camptocormia. Muscle MRI qualifies as a tool for categorizing phases of camptocormia as acute or chronic, with potential consequences for therapeutic approaches. The involvement of muscles beyond an isolated impairment of the paravertebral muscles implies a more systemic view with a deregulation of lumbar trunk muscles.

  17. Three cases of CLIPPERS: a serial clinical, laboratory and MRI follow-up study.

    Kastrup, O; van de Nes, J; Gasser, T; Keyvani, K

    2011-12-01

    The aim of the study was to further determine the pathophysiology, clinical course, MRI-features and response to therapy of chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS), which has recently been proposed as a rare chronic inflammatory central nervous system disorder responsive to immunosuppressive therapy. Three patients with this rare entity underwent serial clinical and bimonthly MRI follow-up over a period of up to 16 months. Extensive laboratory work-up and brain biopsy were performed. Intravenous methylprednisolone or oral dexamethasone was administered as treatment, additionally cyclophosphamide in one patient. Clinically, diplopia, nystagmus, ataxia and facial paresthesia were the cardinal symptoms. Magnetic resonance imaging (MRI) disclosed patchy spot-like gadolinium enhancement in a "salt-and-pepper like appearance" in the pons, midbrain and cerebellum, in two cases with thalamic and in the other with spinal involvement. Brain biopsies demonstrated a predominantly angiocentric but also diffuse infiltration pattern by small mature lymphocytes. Treatment with steroids led to rapid clinical improvement and marked resolution of MRI lesions. As discontinuation of steroids led to clinical relapse, one patient was treated with a further course of steroids and the other with steroids and cyclophosphamide as immunosuppressive therapy. This led to stable remission with only mild clinical residue and normalization of MRI. Extensive laboratory and radiological work-up could not identify any other cause of the disease. Of note, in two cases a marked elevation of IgE in serum was found initially and throughout the course. CLIPPERS seems to be a distinct inflammatory central nervous system disorder. It shows characteristic MRI core features. Extrapontine involvement seems to be frequent. Histologically it is characterised by predominantly angiocentric infiltration by small mature lymphocytes. A pathogenetic

  18. New method for predicting estrogen receptor status utilizing breast MRI texture kinetic analysis

    Chaudhury, Baishali; Hall, Lawrence O.; Goldgof, Dmitry B.; Gatenby, Robert A.; Gillies, Robert; Drukteinis, Jennifer S.

    2014-03-01

    Magnetic Resonance Imaging (MRI) of breast cancer typically shows that tumors are heterogeneous with spatial variations in blood flow and cell density. Here, we examine the potential link between clinical tumor imaging and the underlying evolutionary dynamics behind heterogeneity in the cellular expression of estrogen receptors (ER) in breast cancer. We assume, in an evolutionary environment, that ER expression will only occur in the presence of significant concentrations of estrogen, which is delivered via the blood stream. Thus, we hypothesize, the expression of ER in breast cancer cells will correlate with blood flow on gadolinium enhanced breast MRI. To test this hypothesis, we performed quantitative analysis of blood flow on dynamic contrast enhanced MRI (DCE-MRI) and correlated it with the ER status of the tumor. Here we present our analytic methods, which utilize a novel algorithm to analyze 20 volumetric DCE-MRI breast cancer tumors. The algorithm generates post initial enhancement (PIE) maps from DCE-MRI and then performs texture features extraction from the PIE map, feature selection, and finally classification of tumors into ER positive and ER negative status. The combined gray level co-occurrence matrices, gray level run length matrices and local binary pattern histogram features allow quantification of breast tumor heterogeneity. The algorithm predicted ER expression with an accuracy of 85% using a Naive Bayes classifier in leave-one-out cross-validation. Hence, we conclude that our data supports the hypothesis that imaging characteristics can, through application of evolutionary principles, provide insights into the cellular and molecular properties of cancer cells.

  19. The Plus 50 Initiative Evaluation: Initiative Impact

    American Association of Community Colleges (NJ1), 2012

    2012-01-01

    The American Association of Community Colleges (AACC), with funding from The Atlantic Philanthropies, created the Plus 50 Initiative (2008-2012). This initiative was designed to build the capacity of community colleges nationwide to develop programming that engages the plus 50 learner. This report contains: (1) An overview of the Plus 50…

  20. Pharmacological MRI (phMRI) of the Human Central Nervous System.

    Lanfermann, H; Schindler, C; Jordan, J; Krug, N; Raab, P

    2015-10-01

    Pharmacological magnetic resonance imaging (phMRI) of the central nervous system (CNS) addresses the increasing demands in the biopharma industry for new methods that can accurately predict, as early as possible, whether novel CNS agents will be effective and safe. Imaging of physiological and molecular-level function can provide a more direct measure of a drug mechanism of action, enabling more predictive measures of drug activity. The availability of phMRI of the nervous system within the professional infrastructure of the Clinical Research Center (CRC) Hannover as proof of concept center ensures that advances in basic science progress swiftly into benefits for patients. Advanced standardized MRI techniques including quantitative MRI, kurtosis determination, functional MRI, and spectroscopic imaging of the entire brain are necessary for phMRI. As a result, MR scanners will evolve into high-precision measuring instruments for assessment of desirable and undesirable effects of drugs as the basic precondition for individually tailored therapy. The CRC's Imaging Unit with high-end large-scale equipment will allow the following unique opportunities: for example, identification of MR-based biomarkers to assess the effect of drugs (surrogate parameters), establishment of normal levels and reference ranges for MRI-based biomarkers, evaluation of the most relevant MRI sequences for drug monitoring in outpatient care. Another very important prerequisite for phMRI is the MHH Core Facility as the scientific and operational study unit of the CRC partner Hannover Medical School. This unit is responsible for the study coordination, conduction, complete study logistics, administration, and application of the quality assurance system based on required industry standards.

  1. MRI of Enterovirus 71 myelitis with monoplegia

    Shen, W.C. [Department of Radiology, and School of Medicine, China Medical College, China Medical College Hospital, Taiwan (Taiwan); Tsai, C.H. [Department of Paediatrics, and School of Medicine, China Medical College, China Medical College Hospital, Taiwan (Taiwan); Chiu, H.H. [Department of Paediatrics, China Medical College Hospital, No. 2 Yuh-Der Road, 407 Taichung, Taiwan (Taiwan); Chow, K.C. [Department of Medical Research, China Medical College Hospital, Taichung, Taiwan (Taiwan)

    2000-02-01

    We report two boys diagnosed as having herpangina and hand-foot-mouth disease complicated by monoplegia during the outbreak enterovirus infection in Taiwan in 1998. Enterovirus 71 was identified in the stool and throat swab; neither polio nor Coxsackie viruses was identified. MRI showed unilateral lesions in the anterior horns of the spinal cord at T11-12 and C2-5. Although the MRI findings and sites of these lesions were similar to those of poliovirus-associated poliomyelitis, the virological data indicated that these boys were infected with enterovirus type 71. (orig.)

  2. Acute MRI Changes in Progressive Ischemic Stroke

    Kalowska, Elizabeth; Rostrup, Egill; Rosenbaum, S

    2008-01-01

    aimed to assess if acute MRI findings could be used for the prediction of stroke in progression (SIP). Methods: Prospectively 41 patients, 13 with lacunar infarcts and 28 with territorial infarcts, were admitted to an acute stroke unit within 24 h of stroke onset (median 11 h, range 3- 22). Diffusion...... the modified Rankin Scale, Barthel Index and SSS score. Patients with and without SIP were compared using both clinical and MRI data obtained on admission, on day 7 and after 3 months. Results: Fifteen patients (37%) developed SIP. Increased DWI lesion volume on day 7 in all strokes was associated with SIP...

  3. Acute MRI changes in progressive ischemic stroke

    Kalowska, E.; Rostrup, E.; Rosenbaum, S.

    2008-01-01

    aimed to assess if acute MRI findings could be used for the prediction of stroke in progression (SIP). METHODS: Prospectively 41 patients, 13 with lacunar infarcts and 28 with territorial infarcts, were admitted to an acute stroke unit within 24 h of stroke onset (median 11 h, range 3- 22). Diffusion...... the modified Rankin Scale, Barthel Index and SSS score. Patients with and without SIP were compared using both clinical and MRI data obtained on admission, on day 7 and after 3 months. RESULTS: Fifteen patients (37%) developed SIP. Increased DWI lesion volume on day 7 in all strokes was associated with SIP...

  4. Bayesian segmentation of brainstem structures in MRI

    Iglesias, Juan Eugenio; Van Leemput, Koen; Bhatt, Priyanka

    2015-01-01

    In this paper we present a method to segment four brainstem structures (midbrain, pons, medulla oblongata and superior cerebellar peduncle) from 3D brain MRI scans. The segmentation method relies on a probabilistic atlas of the brainstem and its neighboring brain structures. To build the atlas, we...... the brainstem structures in novel scans. Thanks to the generative nature of the scheme, the segmentation method is robust to changes in MRI contrast or acquisition hardware. Using cross validation, we show that the algorithm can segment the structures in previously unseen T1 and FLAIR scans with great accuracy...

  5. Imaging the premature brain: ultrasound or MRI?

    Vries, Linda S. de; Benders, Manon J.N.L.; Groenendaal, Floris [UMC Utrecht, Department of Neonatology, Wilhelmina Children' s Hospital, PO Box 85090, Utrecht (Netherlands)

    2013-09-15

    Neuroimaging of preterm infants has become part of routine clinical care, but the question is often raised on how often cranial ultrasound should be done and whether every high risk preterm infant should at least have one MRI during the neonatal period. An increasing number of centres perform an MRI either at discharge or around term equivalent age, and a few centres have access to a magnet in or adjacent to the neonatal intensive care unit and are doing sequential MRIs. In this review, we try to discuss when best to perform these two neuroimaging techniques and the additional information each technique may provide. (orig.)

  6. Diagnostic value of MRI in tuberculous meningitis

    Tayfun, C. [Dept. of Diagnostic Radiology, Guelhane Military Medical Academy and Medical School, Ankara (Turkey); Uecoez, T. [Dept. of Diagnostic Radiology, Guelhane Military Medical Academy and Medical School, Ankara (Turkey); Tasar, M [Dept. of Diagnostic Radiology, Guelhane Military Medical Academy and Medical School, Ankara (Turkey); Atac, K. [Dept. of Diagnostic Radiology, Guelhane Military Medical Academy and Medical School, Ankara (Turkey); Ogur, E. [Dept. of Diagnostic Radiology, Guelhane Military Medical Academy and Medical School, Ankara (Turkey); Oeztuerk, T. [Dept. of Diagnostic Radiology, Guelhane Military Medical Academy and Medical School, Ankara (Turkey); Yinanc, M.A. [Dept. of Diagnostic Radiology, Guelhane Military Medical Academy and Medical School, Ankara (Turkey)

    1996-06-01

    In this study 15 patients with clinical findings and positive cerebrospinal fluid analyses for tuberculous meningitis were evaluated with magnetic resonance imaging (MRI). Tuberculous meningitis was diagnosed in 11 cases when thick meningeal enhancement was present after intravenous injection of gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA) in T1-weighted images. Intra-axial tuberculomas were present in 8 patients, 2 of whom had intra-axial tuberculomas without MRI evidence of meningitis. Tuberculomas showed ring or nodular enhancement in postcontrast T1-weighted images, but the most significant MR feature of intraparenchymal tuberculomas was the hypointense appearance of the lesions on T2-weighted images. (orig.)

  7. Isovaleric acidaemia: cranial CT and MRI findings

    Sogut, Ayhan; Acun, Ceyda; Tomsac, Nazan; Demirel, Fatma [Department of Paediatrics, Karaelmas University, Zonguldak (Turkey); Aydin, Kubilay [Department of Radiology, Istanbul Medical School, Istanbul University, Camlikyolu, B. mehmetpasa sokak yavuz apt. No:10/10, Etiler, Istanbul (Turkey); Aktuglu, Cigdem [Department of Paediatrics, Cerrahpasa Medical School, Istanbul University, Istanbul (Turkey)

    2004-02-01

    Isovaleric acidaemia is an inborn error of leucine metabolism due to deficiency of isovaleryl-CoA dehydrogenase, which results in accumulation of isovaleric acid in body fluids. There are acute and chronic-intermittent forms of the disease. We present the cranial CT and MRI findings of a 19-month-old girl with the chronic-intermittent form of isovaleric acidaemia. She presented with severe metabolic acidosis, hyperglycaemia, glycosuria, ketonuria and acute encephalopathy. Cranial CT revealed bilateral hypodensity of the globi pallidi. MRI showed signal changes in the globi pallidi and corticospinal tracts of the mesencephalon, which were hypointense on T1-weighted and hyperintense on T2-weighted images. (orig.)

  8. Support Vector Machine Classification For MRI Images

    Rajeswari S; Theiva Jeyaselvi. K

    2012-01-01

    -Magnetic resonance imaging (MRI) is an imaging technique that has played an important role in neuro science research for studying brain images. Classification is an important part in order to distinguish between normal patients and those who have the p o s s i b i l i t y o f h a v i n g a b n o r m a l i t i e s o r tumor. In this paper, we have obtained the texture based features such as GLCM (Grey Level Co-occurrence Matrix) of MRI images. To select the discriminative features among them ...

  9. Lymphocytic adenohypophysitis: skull radiographs and MRI

    Saiwai, S.; Miyamoto, T. [Department of Radiology, Kobe Central Municipal Hospital, Hyogo (Japan); Inoue, Y.; Nemoto, Y.; Tashiro, T. [Department of Radiology, Osaka City University Medical School (Japan); Ishihara, T. [Department of Endocrinology, Kobe Central Municipal Hospital, Hyogo (Japan); Matsumoto, S. [Department of Neurosurgery, Kobe Central Municipal Hospital, Hyogo (Japan); Hakuba, A. [Department of Neurosurgery, Osaka City University Medical School, 1-5-7 Asahimachi, Abeno, Osaka, 545 (Japan)

    1998-02-01

    We report the skull radiograph, CT and MRI findings in three patients with lymphocytic adenohypophysitis mimicking pituitary adenoma. All cases were associated with pregnancy. CT demonstrated a pituitary mass but did not differentiate lymphocytic adenohypophysitis from pituitary adenoma. The skull radiographs showed either a normal sella turcica or minimal abnormalities; they did not show ballooning or destruction. The MRI appearances were distinctive: relatively low signal on T1-weighted images; preservation of the bright posterior pituitary lobe despite the presence of a relatively large pituitary mass, less common in macroadenomas; marked contrast enhancement compared with pituitary macroadenomas; and dural enhancement adjacent to a pituitary mass. (orig.) With 3 figs., 1 tab., 40 refs.

  10. FULLY AUTOMATIC FRAMEWORK FOR SEGMENTATION OF BRAIN MRI IMAGE

    2005-01-01

    Automaticbraintissuesegmentationfrommag neticresonanceimages(MRI)isofgreatimportance forresearchandclinicalstudyofmuchneurological pathology.Duringthepastdecade,theMRIhashad agreatimpactonthediagnosticimagingofmosthu manorgansystem.ThesegmentationofbrainMRI imagesplaysanimportantroleinthevolumerecon structionforavarietyofmedicalimageanalysis, computer aideddiagnosis,three dimensionalrecon structionandvisualizationapplications.Theaccu rateSegmentationofMRimagesintodifferenttis sueclasses,especiallygray...

  11. Standard high-resolution pelvic MRI vs. low-resolution pelvic MRI in the evaluation of deep infiltrating endometriosis

    Scardapane, Arnaldo; Lorusso, Filomenamila; Ferrante, Annunziata; Stabile Ianora, Amato Antonio; Angelelli, Giuseppe [University Hospital ' ' Policlinico' ' of Bari, Interdisciplinary Department of Medicine, Bari (Italy); Scioscia, Marco [Sacro Cuore Don Calabria General Hospital, Department of Obstetrics and Gynecology, Negrar, Verona (Italy)

    2014-10-15

    To compare the capabilities of standard pelvic MRI with low-resolution pelvic MRI using fast breath-hold sequences to evaluate deep infiltrating endometriosis (DIE). Sixty-eight consecutive women with suspected DIE were studied with pelvic MRI. A double-acquisition protocol was carried out in each case. High-resolution (HR)-MRI consisted of axial, sagittal, and coronal TSE T2W images, axial TSE T1W, and axial THRIVE. Low-resolution (LR)-MRI was acquired using fast single shot (SSH) T2 and T1 images. Two radiologists with 10 and 2 years of experience reviewed HR and LR images in two separate sessions. The presence of endometriotic lesions of the uterosacral ligament (USL), rectovaginal septum (RVS), pouch of Douglas (POD), and rectal wall was noted. The accuracies of LR-MRI and HR-MRI were compared with the laparoscopic and histopathological findings. Average acquisition times were 24 minutes for HR-MRI and 7 minutes for LR-MRI. The more experienced radiologist achieved higher accuracy with both HR-MRI and LR-MRI. The values of sensitivity, specificity, PPV, NPV, and accuracy did not significantly change between HR and LR images or interobserver agreement for all of the considered anatomic sites. LR-MRI performs as well as HR-MRI and is a valuable tool for the detection of deep endometriosis extension. (orig.)

  12. Bilateral Carotid and Vertebral Rete Mirabile Presenting with a Prominent Anterior Spinal Artery Mimicking a Spinal Dural AV Fistula at MRI

    Lee, Seung Young; Cha, Sang Hoon [Chungbuk National University College of Medicine, Iksan (Korea, Republic of)

    2011-11-15

    Bilateral carotid and vertebral rete mirabile (CVRM) is a very rare condition. We report a new case of CVRM initially detected by magnetic resonance imaging (MRI) of the cervical spine. MRI demonstrated tortuous vascular signal voids limited to the anterior cerebrospinal fluid space mimicking spinal dural arteriovenous fistula. A diagnosis of CVRM was confirmed on the basis of angiographic findings of rete formation associated with bilateral aplasia of the cavernous internal carotid and vertebral arteries without abnormal arteriovenous connection.

  13. SPECT/CT versus MRI in patients with nonspecific pain of the hand and wrist - a pilot study

    Huellner, Martin W.; Buerkert, Alexander; Schleich, Florian S.; Strobel, Klaus; Veit-Haibach, Patrick [Lucerne Cantonal Hospital, Department of Radiology and Nuclear Medicine, Lucerne (Switzerland); Schuerch, Maja; Hug, Urs; Wartburg, Urs von [Lucerne Cantonal Hospital, Department of Hand and Plastic Surgery, Lucerne (Switzerland)

    2012-05-15

    Hand and wrist pain is a diagnostic challenge for hand surgeons and radiologists due to the complex anatomy of the involved small structures. The American College of Radiology recommends MRI as the study of choice in patients with chronic wrist pain if radiographs are negative. Lately, state-of-the-art SPECT/CT systems have been introduced and may help in the diagnosis of this selected indication. This retrospective study included 21 patients with nonspecific pain of the hand/wrist. The diagnosis of nonspecific wrist pain was made by the referring hand surgeon based on patient history, clinical examination, plain radiography and clinical guidelines. All patients received planar early-phase imaging and late-phase SPECT/CT imaging as well as MRI. Lesions were divided into major (causative) and minor (not causative) pathologies according to clinical follow-up. Furthermore, oedema-like bone marrow changes seen on MRI were compared with focally increased tracer uptake seen on SPECT/CT images. MRI yielded a quite high sensitivity (0.86), but a low specificity (0.20). In contrast, SPECT/CT yielded a high specificity (1.00) and a low sensitivity (0.71). Oedema-like bone marrow changes were detected in 15 lesions in 11 patients. In ten lesions with bone marrow oedema on MRI, foci of elevated tracer uptake were detected on SPECT/CT. Overall, MRI was more sensitive, but SPECT/CT was more specific in the evaluation of causative pathologies. In this initial comparison, SPECT/CT showed higher specificity than MRI in the evaluation of causative pathologies in patients with nonspecific wrist pain. However, MRI was more sensitive. Thus, SPECT/CT was shown to be a useful problem-solving tool in the diagnostic work-up of these patients. (orig.)

  14. Focal cortical dysplasia of the temporal lobe with late-onset partial epilepsy: serial quantitative MRI

    Rademacher, J.; Seitz, R.J. [Department of Neurology, Heinrich-Heine University Duesseldorf (Germany); Aulich, A. [Department of Radiology, Heinrich-Heine University, Duesseldorf (Germany); Reifenberger, G. [Department of Neuropathology, Heinrich-Heine University, Duesseldorf (Germany); Kiwit, J.C.W. [Department of Neurosurgery, Heinrich-Heine University, Duesseldorf (Germany); Langen, K.J.; Schmidt, D. [Institute of Medicine, Research Center Juelich, Heinrich-Heine University, Duesseldorf (Germany)

    2000-06-01

    We describe serial studies of focal cortical dysplasia causing temporal lobe seizures and progressive aphasia in a 54-year-old woman. Initially, MRI volumetry of the temporal lobes showed significant left cortical thickening corresponding to an elevated aminoacid uptake in the left temporoparietal and inferior frontal cortex on SPECT using 3-[{sup 123}I]iodo-{alpha}-methyl-l-tyrosine (IMT). After 1 year there was severe shrinkage of the left temporal lobe, possibly the result of recurrent complex partial seizures. (orig.)

  15. Initialized Fractional Calculus

    Lorenzo, Carl F.; Hartley, Tom T.

    2000-01-01

    This paper demonstrates the need for a nonconstant initialization for the fractional calculus and establishes a basic definition set for the initialized fractional differintegral. This definition set allows the formalization of an initialized fractional calculus. Two basis calculi are considered; the Riemann-Liouville and the Grunwald fractional calculi. Two forms of initialization, terminal and side are developed.

  16. MRI findings and clinical symptoms of patients with epilepsy referring to Valli-e-asr hospital between 2009 and 2010

    Mohammad Dehghani Firuzabadi

    2013-02-01

    Materials and Methods: This descriptive-analytical study, evaluated sixty over- 18 patients with epilepsy from April 2009 through April 2010 presented with seizure in Birjand Vali-e-asr hospital. Pseudo seizure cases, pregnant women with seizure, items with non-initial seizure, and those whose seizure was associated with pyrexia were excluded from the study. After getting the history of the subjects and their examination, the results of diagnosing measures (i.e. EEG, CT, MRI were recorded in a questionnaire. The obtained data was then analysed by means of SPSS (V: 13 at the significant level α=0.05. Results: Sixty patients whose mean age was 34.4 years were assessed generalized tonic-clonic (grand mal seizures were reported in 78.4%. Initial EEG was abnormal in 51.7%, but specific findings were reported to be abnormal in 19.3%. Brain CT and MRI examinations were abnormal in 35% and 50%, respectively. As revealed by MRI scans, the most common trauma was hippocampal sclerosis (30% were abnormal, and the most common epileptogenic trauma spot was the temporal lobe (46.7% MRI was abnormal in 29% of patients<30-or equal to 30 yrs and in 72.4% of subjects over 30 yrs (P=0.001. Besides, it was found that epilepsy was abnormal in Generalized tonic-clonic seizure (42.6% and in other kinds of seizure (76.9% P=0.03. Conclusion: It was found that EEG and brain MRI almost reveal specific features of epileptic cases only in 10% of the subjects, while it is abnormal in 51.3% of all patients with epileptic seizures. Thus, it is more sensitive than CT (35% and even MRI (50%. MRI has a tangible advantage in showing the kind and position of trauma.

  17. Preliminary evaluation of a brain PET insertable to MRI

    Cho, Gyuseng [Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 305-701 South (Korea, Republic of); Choi, Yong [Department of Electronic Engineering, Sogang University, Seoul, 121-742 South (Korea, Republic of); Lee, Jae Sung; An, Hyun Joon [Department of Nuclear Medicine, Seoul National University, Seoul, 110-744 South (Korea, Republic of); Jung, Jin Ho [Department of Electronic Engineering, Sogang University, Seoul, 121-742 South (Korea, Republic of); Park, Hyun Wook; Oh, Chang Hyun; Park, Kyeongjin; Lim, Kyung Taek; Cho, Minsik [Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 305-701 South (Korea, Republic of); Sul, Woo Suk [National NanoFab Center, Deajeon, 305-806 South (Korea, Republic of); Kim, Hyoungtaek; Kim, Hyunduk [Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 305-701 South (Korea, Republic of)

    2014-07-29

    There is a new trend of the medical image that diagnoses a brain disease as like Alzheimer dementia. The first qualified candidate is a PET-MRI fusion modality because MRI is a more powerful anatomic diagnosis tool than other modalities. In our study, in order to solve the high magnetic field from MRI, the development was consisted with four main items such as photo-sensor, PET scanner, MRI head-coil and attenuation correction algorithm development.

  18. Imaging tools to study pharmacology: functional MRI on small rodents

    Elisabeth eJonckers

    2015-10-01

    Full Text Available Functional Magnetic Resonance Imaging (fMRI is an excellent tool to study the effect of pharmacological modulations on brain function in a non-invasive and longitudinal manner. We introduce several blood oxygenation level dependent (BOLD fMRI techniques, including resting state (rsfMRI, stimulus-evoked (st-fMRI, and pharmacological MRI (phMRI. Respectively, these techniques permit the assessment of functional connectivity during rest as well as brain activation triggered by sensory stimulation and/or a pharmacological challenge. The first part of this review describes the physiological basis of BOLD fMRI and the hemodynamic response on which the MRI contrast is based. Specific emphasis goes to possible effects of anaesthesia and the animal’s physiological conditions on neural activity and the hemodynamic response. The second part of this review describes applications of the aforementioned techniques in pharmacologically-induced, as well as in traumatic and transgenic disease models and illustrates how multiple fMRI methods can be applied successfully to evaluate different aspects of a specific disorder. For example, fMRI techniques can be used to pinpoint the neural substrate of a disease beyond previously defined hypothesis-driven regions-of-interest (ROIs. In addition, fMRI techniques allow one to dissect how specific modifications (e.g. treatment, lesion etc. modulate the functioning of specific brain areas (st-fMRI, phMRI and how functional connectivity (rsfMRI between several brain regions is affected, both in acute and extended time frames. Furthermore, fMRI techniques can be used to assess/explore the efficacy of novel treatments in depth, both in fundamental research as well as in preclinical settings. In conclusion, by describing several exemplary studies, we aim to highlight the advantages of functional MRI in exploring the acute and long-term effects of pharmacological substances and/or pathology on brain functioning along with

  19. Cell therapy in myocardial infarction: emphasis on the role of MRI

    Ye, Yuxiang; Bogaert, Jan [University Hospital K.U.L., Department of Radiology, Leuven (Belgium)

    2008-03-15

    Despite tremendous progress in myocardial infarct (MI) treatment, mortality rates remain substantial. Permanent loss of cardiomyocytes after ischemic injury, results in irreversible loss of myocardial contractility, reduction in ventricular performance, and may initiate the development of dilated heart failure. The discovery that pluripotent progenitor cells bear the capacity to differentiate to mature cardiac cells raised the hope of cell-based regenerative medicine. Engraftment of stem cells in the damaged myocardium, repair and functional improvement appeared suddenly a nearby reality. Promising results in animal models, and preliminary studies reporting the feasibility and safety of adult stem cell therapy in MI patients led to the first double-blinded randomized, placebo-controlled trials. The initial great enthusiasm for this paradigm shift in MI treatment has been tempered by the mainly negative or modestly positive study findings. Before new, larger clinical trials can be initiated, a number of critical questions and issues need to be considered starting with a scrutinized analysis of currently available data to extending our knowledge of the mechanism of scarless myocardial regeneration. Cardiac cell therapy necessitates a multidisciplinary approach, whereby imaging, in particular MRI, and the input of the imaging specialist is crucial to the success of cardiac cell regenerative medicine. MRI is an appealing technique for cell trafficking depicting engraftment, differentiation and survival. Endomyocardial cell administration can be achieved safely with MR fluoroscopy and MRI is without any doubt the most accurate and reproducible technique to measure study end-points. (orig.)

  20. Functional MRI experiments : acquisition, analysis and interpretation of data

    Ramsey, NF; Hoogduin, H; Jansma, JM

    2002-01-01

    Functional MRI is widely used to address basic and clinical neuroscience questions. In the key domains of fMRI experiments, i.e. acquisition, processing and analysis, and interpretation of data, developments are ongoing. The main issues are sensitivity for changes in fMRI signal that are associated