European journal of radiology
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Comparative Study
Avascular necrosis (AVN) of the proximal fragment in scaphoid nonunion: is intravenous contrast agent necessary in MRI?
The purpose of this prospective study is to assess the diagnostic value of intravenously applied contrast agent for diagnosing osteonecrosis of the proximal fragment in scaphoid nonunion, and to compare the imaging results with intraoperative findings. ⋯ Viability of the proximal fragment in scaphoid nonunion can be significantly better assessed with the use of contrast-enhanced MRI as compared to nonenhanced MRI. Bone marrow edema is an inferior indicator of osteonecrosis. Application of intravenous gadolinium is recommended for imaging scaphoid nonunion.
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The purpose of this retrospective study was to determine what gives rise to the periportal free air, and ligamentum teres and falciform ligament signs on CT in patients with gastrointestinal (GI) tract perforation, and whether these specific air distributions can play a clinically meaningful role in the diagnosis of gastroduodenal perforation. ⋯ The prediction of the perforation site of the GI tract on CT should be based on the presence of strong predictors of the site of bowel perforation, and the specific free air distribution should be regarded as complementary predictors.
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To describe the imaging signs of idiopathic osteonecrosis of the scaphoid (Preiser's disease) and to differentiate the findings from scaphoid nonunion. ⋯ Pathoanatomy of Preiser's disease and the differentiation into three zones of bone marrow viability can be explained with the retrograde blood supply of the scaphoid. In its natural course, three different stages can be depicted with the initial stage seen only in MRI.
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To audit our experience with ultrasound-guided thrombin injection for the treatment of iatrogenic femoral artery pseudoaneurysms. ⋯ Percutaneous ultrasound-guided thrombin injection of is a quick, effective and safe treatment for iatrogenic femoral pseudoaneurysms. For larger pseudoaneurysms, although it is worth attempting more than one thrombin injection, endovascular repair may eventually be required.
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In diffusion-weighted magnetic resonance imaging (DWI), the intensity of the acquired magnetic resonance signal depends on the self-diffusion of the excited spins, i.e., on the microscopic stochastic Brownian molecular motion. Since the extent and orientation of molecular motion is influenced by the microscopic structure and organization of biological tissues, DWI can depict various pathological changes of organs or tissues. While DWI of the brain can be considered an established technique since the mid-1990s, significantly fewer studies have been published about DWI in body imaging, mainly because of the relatively low robustness of conventional DWI methods in non-neurological applications. ⋯ Hence, several alternative (non-echo-planar) diffusion-weighting pulse sequence types were proposed and evaluated for DWI applications in the body. In this review article, first the basics of molecular diffusion and of diffusion-weighted MRI are introduced and then several specific MRI techniques, which have been used for DWI of the body, are described. Finally, protocol recommendations for different DWI applications in the body are provided.