Pearls & Oy-sters: A distinctive watershed area in the vertebrobasilar territory

Abstract

The middle cerebellar peduncles may represent a distinctive watershed area in the vertebrobasilar circulation between the anterior inferior and superior cerebellar arteries. A 78-year-old man experienced 2 short-lasting episodes of vertigo with unstable gait during the 5 days before admission. One week previously, he had carried large fiberboard panels, involving sustained rotation of the neck in both directions. His past medical history included arterial hypertension and dyslipidemia. The initial general and neurologic examination was normal except for high blood pressure (194/109 mm Hg). Over the next few days, the patient developed rapidly worsening bilateral dysmetria and dysdiadochokinesia, more marked on the left, cerebellar dysarthria, and unstable stance and gait. Cerebral CT showed leukoaraiosis and lacunar sequelae of both corona radiata and of the left thalamus and caudate nucleus. CT arteriography showed narrowing and irregularities of the V2 segment of the left vertebral artery and occlusion of its V3 segment. Ultrasonography and Doppler examination confirmed the stenosis of the left V2 segment and occlusion of the left V4 segment. There was also an 80% stenosis in the V2 segment of the right vertebral artery. Cerebral MRI showed symmetric acute ischemia of both middle cerebellar peduncles (MCPs) and of the deep right cerebellar hemisphere (figure, A). Fat saturation sequences showed a wall hematoma …