The purpose of this study was to compare CT angiography with digital subtraction angiography (DSA) in the detection and measurement of intracranial aneurysms in patients with acute subarachnoid hemorrhage. Thirty consecutive patients with recent subarachnoid hemorrhage shown by unenhanced CT scanning or lumbar puncture were studied with CT angiography and DSA. Using a shaded surface display format and source images, two reviewers working independently blindly interpreted CT angiograms for presence and size of aneurysms. Sensitivity and specificity for aneurysm detection were calculated for each reviewer. Aneurysm size measurements were compared between reviewers and between the two imaging techniques. Thirty aneurysms were found in 22 patients with DSA; eight patients had no aneurysms. The sensitivity and specificity of CT angiography for reviewer A were 0.97 and 1.0, respectively. For reviewer B, the sensitivity and specificity were 0.77 and 0.87, respectively. All cases with single aneurysms on DSA (18 patients) had surgical confirmation of aneurysm location and rupture. In each case with multiple aneurysms (four patients), the aneurysm thought responsible for the hemorrhage was surgically confirmed. In those cases with no aneurysms found on DSA, follow-up DSA studies did not reveal additional findings. Differences between reviewers in aneurysm size measurements made with CT angiography were not significant (p = .10). Mean aneurysm measurements for reviewer A, reviewer B, and DSA were 6.6 mm, 7.0 mm, and 6.9 mm, respectively. CT angiography shows potential in the detection and measurement of aneurysms in patients with acute subarachnoid hemorrhage when compared with DSA.
In this report, we challenge the commonly held assumption that the adult respiratory distress syndrome (ARDS) is a homogeneous process associated with generalized and relatively uniform damage to the alveolar capillary membrane. We studied 13 patients with ARDS, comparing the pulmonary parenchymal changes seen by standard bedside chest roentgenograms with those seen by computed tomography of the chest. Three patients demonstrated generalized lung involvement by both radiologic techniques. In another eight patients, despite the appearance of generalized involvement on the standard chest x-ray film, the computed tomographic scans showed patchy infiltrates interspersed with areas of normal-appearing lung. Two patients showed patchy involvement by both techniques. The fact that ARDS spares some regions of lung parenchyma is useful knowledge in understanding the gas-exchange abnormalities of ARDS, the variable responsiveness to positive end-expiratory pressure, and the occurrence of oxygen toxicity. The problem of regional inhomogeneity should also be kept in mind when interpreting lung biopsy specimens or bronchoalveolar lavage fluid in patients with ARDS. (JAMA1986;255:2463-2465)
By observing the fat-signal peak on the spectral display of a magnetic resonance (MR) imager while varying inversion time (TI), the authors determined the TI that produced the lowest fat peak for the best suppression of fat signal in subsequent short-TI inversion-recovery (STIR) MR imaging. In 25 volunteers who underwent imaging at multiple TIs, the TI that produced the lowest measured fat signal intensity was the same as that selected by means of TI tuning in 60% of cases and was within 5 msec in the remaining 40%.
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