Duplicated posterior inferior cerebellar arteries one of which was supplied by the jugular branch of the ascending pharyngeal artery

Purpose To describe a case of duplicated posterior inferior cerebellar arteries (PICAs), one of which was supplied by the jugular branch of the ascending pharyngeal artery (APA). Case report A 62-year-old man with cerebral infarction underwent cranial magnetic resonance (MR) imaging and MR angiography. MR angiography showed a hyperplastic left APA, that was found to enter the posterior cranial fossa and continue to the PICA. Another left PICA arising from the V4 segment of the left vertebral artery (VA) and a tiny left anterior inferior cerebellar artery (AICA) were also identified. The source images of MR angiography revealed that the anomalous artery was passing through the medial side of the jugular foramen pars vascularis. The two left PICAs did not fuse to each other. Discussion There are four types of the PICA arising from the carotid system: (1) the PICA arises from the cavernous segment of the internal carotid artery (ICA) (persistent trigeminal artery variant); (2) the PICA arises from the cervical segment of the ICA (persistent hypoglossal artery variant); (3) the PICA arises from the APA via the hypoglossal canal; and (4) the PICA arises from the APA via the jugular foramen. Two PICAs sometimes arise from the V4 segment of the VA. In this common variation, the AICA is usually absent. This is the first reported case involving the association of (4) and a duplicated PICA with a tiny AICA. Conclusion To identify this variation, careful observation of source images and creation of partial maximum-intensity-projection images of MR angiography are important.