Radiographics : a review publication of the Radiological Society of North America, Inc
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The dual-energy computed tomographic (CT) technique allows the differentiation of materials with large atomic numbers such as iodine and xenon. The basic principle of dual-energy CT is material decomposition based on attenuation differences at different energy levels. ⋯ Furthermore, the virtual nonenhanced dual-energy CT technique can be used for the evaluation of pulmonary nodule characteristics without acquisition of true nonenhanced CT images. Knowledge of the applications of dual-energy CT and the typical images produced may lead to wider use of dual-energy CT for pulmonary applications and better interpretation of the results.
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Magnetic resonance (MR) imaging is an important imaging technique in the evaluation of scrotal masses, providing a useful adjunct to ultrasonography (US). Although US is the modality of choice for initial evaluation of scrotal pathologic conditions because of its wide availability, low cost, and high sensitivity for detection of testicular and paratesticular disease processes, US findings may occasionally be inconclusive. ⋯ This article reviews and illustrates the MR imaging features of solid extratesticular and intratesticular benign and malignant scrotal tumors, as well as nonneoplastic lesions that can mimic neoplasia. Normal scrotal MR anatomic features and optimal MR imaging technique are also presented.
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Vasculitis is an inflammatory destructive process affecting blood vessels. Pulmonary vasculitis may be secondary to other conditions or constitute a primary, and in most cases idiopathic, disorder. Underlying conditions in the secondary vasculitides are infectious diseases, connective tissue diseases, malignancies, and hypersensitivity disorders. ⋯ Diffuse alveolar hemorrhage is a clinical syndrome that usually results from primary small-vessel vasculitis in the lungs. Although chest radiography is often the first imaging study performed in patients with pulmonary involvement by vasculitis, chest radiographs often fail to show the exact pattern and extent of thoracic involvement and CT is more useful in assessment of the thoracic findings. The pulmonary primary vasculitides are rare disorders, and their diagnoses are among the most demanding challenges in medicine because their signs and symptoms are nonspecific and overlap with those of infections, connective tissue diseases, and malignancies; thus, diagnosis of vasculitis relies on recognition of characteristic combinations of particular clinical, radiologic, laboratory, and histopathologic features.
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Biography Historical Article
Congratulations to the 2009 RSNA Outstanding Educator: Elliot K. Fishman, MD.