Radiographics : a review publication of the Radiological Society of North America, Inc
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Chronic pulmonary thromboembolism is mainly a consequence of incomplete resolution of pulmonary thromboembolism. Increased vascular resistance due to obstruction of the vascular bed leads to pulmonary hypertension. Chronic thromboembolic pulmonary hypertension is clearly more common than previously was thought, and misdiagnosis is common because patients often present with nonspecific symptoms related to pulmonary hypertension. ⋯ The parenchymal signs include scars, a mosaic perfusion pattern, focal ground-glass opacities, and bronchial anomalies. The presence of one or more of these radiologic signs arouses suspicion and allows diagnosis of this entity. Early recognition of chronic pulmonary thromboembolism may help improve the outcome, since the condition is potentially curable with pulmonary thromboendarterectomy.
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Fatty liver disease is the most common cause of chronic liver disease in the United States. Noninvasive detection and quantification of fat is becoming more and more important clinically, due in large part to the growing prevalence of nonalcoholic fatty liver disease. ⋯ Several magnetic resonance (MR) imaging-based techniques--including chemical shift imaging, frequency-selective imaging, and MR spectroscopy--are currently in clinical use for the detection and quantification of fat-water admixtures, with each technique having important advantages, disadvantages, and limitations. These techniques permit the breakdown of the net MR signal into fat and water signal components, allowing the quantification of fat in liver tissue, and are increasingly being used in the diagnosis, treatment, and follow-up of fatty liver disease.
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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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Thoracic injuries are significant causes of morbidity and mortality in trauma patients. These injuries account for approximately 25% of trauma-related deaths in the United States, second only to head injuries. ⋯ In addition to conventional radiography, multidetector computed tomography (CT) is increasingly being used, since it can quickly and accurately help diagnose a wide variety of injuries in trauma patients. Furthermore, multiplanar and volumetric reformatted CT images provide improved visualization of injuries, increased understanding of trauma-related diseases, and enhanced communication between the radiologist and the referring clinician.
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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.