Radiographics : a review publication of the Radiological Society of North America, Inc
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Small bowel obstruction (SBO) is a common clinical syndrome for which effective treatment depends on a rapid and accurate diagnosis. Despite advances in imaging and a better understanding of small bowel pathophysiology, SBO is often diagnosed late or misdiagnosed, resulting in significant morbidity and mortality. A comprehensive approach that includes clinical findings, patient history, and triage examinations such as plain abdominal radiography will help the clinician develop an individualized treatment plan. ⋯ If a complete or high-grade obstruction is suspected, cross-sectional studies such as ultrasonography or multidetector CT are used to exclude strangulation. An algorithmic approach to imaging is proposed for the management of SBO to achieve accurate diagnosis of the obstruction; determine its severity, site, and cause; and assess the presence of strangulation. Radiologists have a pivotal role in clinical decision making in cases of SBO by providing answers to specific questions that significantly affect management.
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Review Comparative Study
3.0-T MR imaging of the abdomen: comparison with 1.5 T.
Three-tesla magnetic resonance (MR) imaging offers substantially higher signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) than 1.5-T MR imaging does, which can be used to improve image resolution and shorten imaging time. Because of these increases in SNR and CNR, as well as changes in T1 and T2 relaxation times, an increase in magnetic susceptibility, and an increase in chemical shift effect, many abdominal applications can benefit from 3.0-T imaging. Increased CNR obtained with a gadolinium-based contrast agent improves lesion conspicuity, requires less intravenous contrast material, and improves MR angiography by increasing spatial and temporal resolution. ⋯ Radiofrequency field inhomogeneity is also a major concern in imaging larger fields of view and often leads to standing wave effects and large local variations in signal intensity. Many issues related to MR device compatibility and safety have yet to be addressed at 3.0 T. A 3.0-T MR imaging system has a higher initial cost and a higher cost of upkeep than a 1.5-T system does.
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High-frequency ultrasonography (US) with a linear-array transducer is the modality of choice for the initial evaluation of patients with acute scrotal pain after trauma. Testicular trauma is the third most common cause of acute scrotal pain. ⋯ In addition, 10% of testicular tumors are found incidentally at US performed for the evaluation of trauma. If a conservative approach is adopted for the management of an intratesticular abnormality after trauma, follow-up US should be performed until the images show a complete resolution of the abnormality, so that a tumor will not be missed.
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Fractures and dislocations of the carpal bones are more common in young active patients. These injuries can lead to pain, dysfunction, and loss of productivity. Conventional radiography remains the primary imaging modality for evaluation of suspected carpal fractures and dislocations. ⋯ Multidetector CT can easily display the extent of carpal fractures and dislocations, often depicting fractures that are occult at radiography. In addition, with multiplanar (two-dimensional) and volumetric (three-dimensional) reformation, pathologic conditions and anatomic relationships are better perceived. This information can be easily conveyed to orthopedic and trauma surgeons and can be crucial for surgical treatment and planning.
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Urethral injury is a common complication of pelvic trauma that, if undiagnosed, may lead to significant long-term morbidity. Segments of the urethra that are near the pubic rami and the puboprostatic ligaments are particularly vulnerable. ⋯ However, even for radiologists who are familiar with standard technique, urethrography after pelvic trauma may be particularly challenging because the patient is immobile or a surgical fixation device or indwelling urethral catheter is present. Various methods may used to overcome these difficulties and ensure that optimal images are obtained so that a correct diagnosis can be made without additional imaging evaluations.