Variations of the superior cerebellar artery: MR angiographic demonstration

PURPOSE: The purpose of this study was to describe variations of the proximal segments of the superior cerebellar artery (SCA) detected by magnetic resonance (MR) angiography. MATERIALS AND METHODS: We reviewed 145 consecutive MR angiograms. All patients were studied with a 1.5-Tesla imager using the three-dimensional time-of-flight technique. RESULTS: There were 16 duplicated SCAs in 13 patients, seven SCAs originating from the posterior cerebral arteries in six patients, four early bifurcations of the SCAs in four patients, and one SCA arising from the internal carotid artery. Because the SCA is small in caliber, the bilateral SCAs in nine patients could not be identified on MR angiograms owing to patient movement. In two patients with duplicated SCA, one of the duplicated trunks compressed the trigeminal nerve at the root entry zone, resulting in trigeminal neuralgia. CONCLUSION: Although most of these SCA variations have no clinical significance, preoperative identification of SCA variations is important for avoiding complications during surgery and/or for interventional procedures of the distal basilar artery.