3-DIMENSIONAL COMPUTED TOMOGRAPHIC ANGIOGRAPHY IN DETECTION OF CEREBRAL ANEURYSMS IN ACUTE SUBARACHNOID HEMORRHAGE

OBJECTIVE: Three-dimensional computed tomographic angiography (CTA) is a recently developed imaging modality. We demonstrate the value of th is noninvasive method in replacing digital subtraction angiography (DS A) in the detection of aneurysms of the circle of Willis in patients w ith subarachnoid hemorrhage admitted to our institution. METHODS: A he lical acquisition was performed for computed tomographic scans obtaine d for 120 patients with a 1 mm per second table speed and a l-mm colli mation, 1:1 pitch. Axial source images were transferred on a console A dvantage Windows workstation (General Electric, Milwaukee, WI) and CTA was obtained using maximum intensity projection reconstruction. All p atients had undergone DSA of the circle of Willis (80 patients preoper atively and 40 postoperatively). RESULTS: A total of 129 aneurysms wer e detected in 107 patients. Three-dimensional CTA disclosed nothing ab normal in 13 patients. Ninety-two patients sustained one aneurysm, 10 patients sustained two, 3 patients sustained three, and 2 patients sus tained four. All results were confirmed by DSA. In two cases, aneurysm s of the middle cerebral artery were detected by CTA but not by DSA. W hen using angiographic views, the aneurysm was always masked by a bran ch of the middle cerebral artery. CONCLUSION: The sensitivity of three -dimensional CTA is comparable with that of DSA, and its specificity i s 100%. Because CTA is simple, quick, noninvasive, and reliable, we th ink that it can eventually replace DSA.