INTRACRANIAL VERTEBROBASILAR SYSTEM - MR-ANGIOGRAPHY

PURPOSE: To determine the reliability of magnetic resonance (MR) angio graphy in depicting normal vascular anatomy and its usefulness in dete cting vascular disease compared with those of digital subtraction angi ography(DSA). MATERIALS AND METHODS: Sixty patients with symptoms refe rable to disease of the vertebrobasilar system were examined with MR a ngiography and DSA. RESULTS: In patients with normal DSA results, all vertebral arteries (VAs) and basilar arteries (BAs) were also visualiz ed with MR angiography. MR angiography demonstrated 117 of 120 superio r cerebellar arteries and 80 of 90 posterior inferior cerebellar arter ies but only 30 of 58 anterior inferior cerebellar arteries. MR angiog raphy demonstrated disease of the VAs and BAs with 100% sensitivity. S tenoses were differentiated from occlusions in all cases. However, the degree of stenosis was overestimated in 63% of patients. In six patie nts with occlusive disease, collateral flow was correctly analyzed wit h selective saturation. CONCLUSION: Despite its limitations, MR angiog raphy is a clinically important noninvasive technique for screening pa tients for macroangiopathy of the posterior arterial supply to the bra in.