Isolated Posteroinferior Cerebellar Artery Dissection Diagnosed by High-Resolution Vessel Wall MRI

Arterial dissection is an important cause of stroke. We report two cases of isolated posterior inferior cerebellar artery (PICA) dissection diagnosed by high-resolution vessel-wall MRI (HRVW-MRI). One subject complained of abrupt-onset vertigo and headache, and the other subject had headache, vertigo, and Horner syndrome. Conventional MRA showed only focal dilatation of the PICA, but HRVW-MRI revealed intramural hematoma and double-lumen contour in the PICA, suggesting arterial dissection. We suggest that the use of HRVW-MRI should be considered when diagnosing isolated PICA dissection in a PICA infarct with an unknown cause.