Patient History
Left lower extremity weakness. NIH stroke scale 3.
Findings
There is effacement of the sulci of the right inferior frontal lobe. There is no evidence of intracranial hemorrhage. There appears to be focal lacunar infarction in the globus pallidus on the right side.CT angiographic images show diminution in the caliber of the left M1 segment of the middle cerebral artery and both cavernous internal carotid arteries. The supraclinoid left internal carotid artery is nearly occluded with high-grade stenosis. The petrous internal carotid arteries are small in caliber, left worse than right. There is rapid tapering of the internal carotid artery caliber shortly after the carotid bifurcations. The common carotid arteries show no areas of stenosis. The patient has a balanced vertebral artery system without stenoses with large V4 segments supplying the basilar artery. The left A1 segment is narrowed. The termination of both supraclinoid internal carotid arteries shows narrowing with moyamoya effect on the right side more so than the left side.The distal anterior cerebral and middle cerebral artery branches show no focal stenosis. The posterior cerebral arteries are unremarkable bilaterally.On the perfusion sequences the cerebral blood flow maps are symmetric from side to side. The cerebral blood volume maps show slight asymmetry in the white matter blood volume. The mean transit time shows mild central delay bilaterally and symmetrically. The same is true with the time to drain with mild watershed anterior delay. Overall the time to drain and Tmax studies show slower drainage of the anterior circulation compared to the posterior circulation.
Impressions
Vascular stenoses of bilateral supraclinoid internal carotid arteries and left M1 segment with moyamoya effect on the left side. No thrombi are detected.
CT perfusion shows no evidence of current infarction but with bilateral diffuse hypoperfusion on time to drain and Tmax and the anterior circulation compared to the posterior circulation especially affecting the watershed zone on the left side between the anterior cerebral and posterior cerebral arteries.
