PURPOSE: To evaluate the role of rotational angiography in the diagnosis, characterization, and postoperativeassessment of aneurysm, and in the analysis of arteriovenous malformation(AVM). MATERIALS AND METHODS: Between May1995 and February 1997, 31 patients who had undergone DSA and rotational angiography were retrospectivelyevaluated. Rotational angiographic and lateral DSA images were compared by two radiologists, and in 22 patientswith aneurysmal clipping, location, visibility of the aneurysmal neck, vascular branch anatomy, and projection andshape of the aneurysm were evaluated. The presence or absence of residual aneurysmal neck was evaluated in eightpostoperative patients, and the anatomy of feeder artery and intranidal aneurysm were evaluated in five AVMpatients. RESULT: Twenty-seven aneurysms were found in 22 of 26 patients in whom DSA had indicated thispossibility. Rotational angiography was superior to conventional DSA in the assessment of neck(67%), vascularbranch anatomy(41%), and projection(22%), location(19%), and shape(15%) of the aneurysm. Rotational angiographyhelped confirm the absence of aneurysm at 11 sites, and was also superior to conventional DSA for confirming theabscence of residual neck in four of eight postoperative patients, and to evaluate feeder artery in four of fiveAVM patients. CONCLUSION: Rotational angiography is better than conventional DSA for the evaluation of aneurysmand AVM.