Large persistent trigeminal artery variant that supplied the subtotal cerebellar hemisphere and caused trigeminal neuralgia, which was diagnosed by magnetic resonance (MR) angiography and MR cisternography.

Abstract

To describe a case of large persistent trigeminal artery (PTA) variant that caused trigeminal neuralgia, which was diagnosed by magnetic resonance (MR) angiography and MR cisternography. An 82-year-old woman with left trigeminal neuralgia underwent cranial MR imaging, MR angiography and MR cisternography. MR imaging revealed no significant abnormality. MR angiography showed that a relatively large artery arose from the precavernous segment of the left internal carotid artery (ICA) without connection to the basilar artery, which is indicative of a PTA variant. This artery supplied the left cerebellar arteries, except for the rostral branch of the superior cerebellar artery. MR cisternography showed that the inferior surface of the left trigeminal nerve was compressed by the PTA variant. She was treated by microvascular decompression surgery and her symptoms disappeared. According to a meta-analysis, the prevalence of the PTA variants is reported to be 0.2%. The majority of PTA variants are small arteries and are classified as the anterior inferior cerebellar artery type. The present case involved a relatively large artery that supplied large territories of the cerebellar hemisphere. PTA and PTA variants rarely cause trigeminal neuralgia. Using MR angiography and MR cisternography, the author diagnosed a case of large PTA variant that caused trigeminal neuralgia. No similar case has been reported in the relevant English language literature.