Radiology
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The endothelium is not a passive blood-compatible lining for the containment of blood cells and plasma, but rather it is a metabolically active tissue that subserves a wide range of functions relating to vascular homeostasis. This article reviews the current understanding of endothelial cell biology in terms of the molecules and biochemical pathways involved. These regulate coagulant and thrombotic properties of the vessel wall, vascular tone, and hence blood flow and pressure; changes in solute permeability and leukocyte traffic during the generation of inflammatory and immune responses; and finally the processes of vessel growth and angiogenesis. The review concludes with a consideration of how these functional properties can be disturbed, and their possible consequences, in response to irradiation, intravascular contrast media, or angioplasty.
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The potential of magnetic resonance (MR) imaging in the evaluation of the female urethra was studied in 64 patients. Spin-echo T1- and T2-weighted images were obtained in all 64 patients, and contrast-enhanced T1-weighted images were also obtained in 27 patients. Urethral pathologic conditions, established with urethroscopy or histologic examination, or both, included urethral diverticula, inflammatory granuloma, and primary and metastatic neoplasms. ⋯ Primary or metastatic urethral neoplasms were also detected with MR imaging in every patient with the diagnosis, but differentiation between benign and malignant disease was not possible. Local staging of primary or metastatic malignant disease was correct in eight of the 11 patients. In three patients, the inflammatory changes could not be differentiated from tumor invasion, resulting in overestimation of tumor extent.
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Computed tomographic (CT) and chest radiographic findings were retrospectively correlated with those found at fiberoptic bronchoscopy (FOB) in 58 patients presenting with hemoptysis. Abnormalities involving the airways were depicted by CT in a total of 28 cases (48%). In 18 of these (31% of the total group of 58), focal abnormalities involving the central airways were identified (17 were subsequently proved to be malignant) and in 10 (17% of the total), CT showed bronchiectasis. ⋯ In 10 of 21 cases (48%) of non-small cell lung cancer, CT allowed definitive staging by documenting either direct mediastinal invasion and/or metastatic disease, while FOB allowed definitive staging in only three cases. CT studies provided no false-negative results. It is concluded that when carefully performed, CT may be an effective modality for evaluating patients presenting with hemoptysis.
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Thirty-two vertebral hemangiomas (VHs) were evaluated with nonenhanced computed tomography (CT), T1-weighted magnetic resonance (MR) imaging, CT enhanced with contrast material, and selective spinal arteriography. The stroma between the osseous trabeculae was found to correspond to either fatty tissue or soft tissue or both. All 11 asymptomatic VHs showed complete fatty stroma at CT and increased signal intensity at MR imaging. ⋯ Predominantly fatty stroma at CT and increased signal intensity at MR imaging were associated with normal or only slightly increased vascularization at selective spinal arteriography or contrast-enhanced CT, while soft-tissue stroma at CT and low signal intensity at MR imaging were associated with distinct hypervascularization. The authors' experience suggests that fatty VHs may represent inactive forms of VH, while soft-tissue content at CT and low signal intensity at MR imaging may indicate a more active vascular lesion with potential to compress the spinal cord. CT and MR imaging may be especially valuable for evaluating patients with clinical signs or symptoms of uncertain origin and findings compatible with VH at plain radiography.