Surgical anatomy of the cerebral arteries in patients with subarachnoid hemorrhage: comparison of computerized tomography angiography and digital subtraction angiography

Object. The purpose of this study was to compare computerized tomography (C T) angiography and digital subtraction (DS) angiography studies in patients with subarachnoid hemorrhage (SAH) to assess their vascular anatomy releva nt to cerebral aneurysm surgery. Methods. From a prospective series of 100 patients, with SAH, the authors s elected 73 patients whose CT angiography studies were of adequate quality a nd in whom DS angiography of both carotid arteries had been performed. Elev en patients with no DS angiographic studies of the vertebrobasilar artery w ere only evaluated for the anterior half of the circle of Willis. Anterior communicating arteries (ACoAs), both precommunicating anterior cerebral art eries (A(1) segments), both posterior communicating arteries (PCoAs), and b oth precommunicating posterior cerebral arteries (P-1 segments) were assess ed on CT angiography and DS angiography by two independent observers. Conclusions. Computerized tomography angiography compares well with DS angi ography for visualizing normal-sized arteries, and is superior for visualiz ing ACoAs and hypoplastic A(1) and P-1 segments. Important preoperative asp ects such as dominant A(1) segments and PCoAs are equally well seen using e ither modality. Neither method enabled the authors to visualize more than 5 0% of PCoAs. Use of CT angiography can provide the required preoperative an atomical information for aneurysm surgery in most patients with SAH.