Magnetic resonance imaging clinics of North America
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Magn Reson Imaging Clin N Am · May 2009
ReviewDiffusion-weighted MR imaging in musculoskeletal radiology: applications in trauma, tumors, and inflammation.
Diffusion-weighted imaging is a noninvasive magnetic resonance technique that is capable of measuring icroscopic movement of water molecules (ie, random or Brownian motion) within biologic tissues. Diffusion weighting is achieved with a pulsed-field gradient that leaves "static" spins unaffected but causes dephasing of spin ensembles that experience different motion histories according to their diffusion paths, with respect to the direction of the gradient. This article focuses on the interesting opportunities of the use of diffusion weighted imaging in the diagnosis of musculoskeletal diseases, including trauma, tumor, and inflammation.
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Magn Reson Imaging Clin N Am · May 2009
ReviewDiffusion-weighted MR imaging for whole body metastatic disease and lymphadenopathy.
Diffusion-weighted (DW) imaging provides a new contrast mechanism for evaluation of tumors of the chest, abdominal, and pelvis. By imaging microscopic motion of water molecules, DW imaging yields new qualitative and quantitative information about tumors that can be used to improve tumor detection, characterize some tumors, and monitor and predict response to treatment. ⋯ Experience with these DW techniques for body applications is still accumulating. However, DW imaging has already become an integral part of body MR imaging protocols at many centers.
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The primary advantage of high field strength MR imaging over imaging on modern 1.5 Tesla (T) systems is increased signal-to-noise ratio, which can be used to improve image quality or shorten scan acquisition time. In the years since 3.0T scanners were first approved for clinical use, one of the areas which has benefited greatly from its introduction is neurovascular MR angiography (MRA). ⋯ This article discusses the current state of neurovascular MRA at 3.0T, basic physical differences between MR imaging at 1.5T and 3.0T, and their effects on MRA sequences. The literature regarding the efficacy of 3.0T MRA techniques for diagnosing specific neurovascular pathologies and carotid steno occlusive disease is reviewed.
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Imaging of the arteries of the lower extremity is most often performed in patients who have known or suspected peripheral artery occlusive disease. Due to the recent advances in imaging modalities, the radiologic approach to the diagnosis of peripheral artery occlusive disease has changed substantially in the last few years. Recent technical developments such as the introduction of new image reconstruction algorithms and dedicated contrast agents have pushed the limits of MR angiography toward higher spatial resolution and image quality and have enabled time-resolved imaging. This article discusses various techniques of peripheral MR angiography, including step-by-step, hybrid, continuous table movement, and non-contrast-enhanced MR angiography.
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There seems to be an association between exposure to intravenous gadolinium-based contrast agents (GBCAs) and nephrogenic systemic fibrosis (NSF), a debilitating and sometimes fatal disease. This article addresses the relationship between GBCAs and NSF and answers some common questions. The policy deployed at Yale-New Haven Hospital for prevention of NSF and screening for patients at risk is delineated and discussed along with recommendations by the Food and Drug Administration.