Intracerebral Hemorrhage after Carotid Artery Stenting without Evidence of Hyperperfusion in Positron Emission Tomography.

A 75-year-old man with a recent history of transient left hemiparesis and dysarthria was referred to our hospital. Angiography showed right internal carotid artery (ICA) occlusion and left ICA 89% stenosis. Positron emission tomography (PET) showed decreased cerebral blood flow (CBF), and increased oxygen extraction fraction (OEF) and cerebral blood volume (CBV) in the right hemisphere. In the left hemisphere, CBV was increased, but CBF and OEF remained normal. One month after the transient ischemic attack, left carotid artery stenting (CAS) was performed without complications. Diffusion-weighted magnetic resonance imaging (MRI) on the day after CAS showed no fresh ischemic lesion. PET on the second day after CAS showed increased CBF and decreased OEF and CBV in the right hemisphere as compared with those before CAS. In the left hemisphere, decreased CBV was observed and CBF was slightly increased as compared with those before CAS. The postoperative course was uneventful, but on the fifth day after CAS, the patient suddenly showed a focal seizure and right motor weakness. Emergency computed tomography scanning showed massive intracranial hemorrhage with severe brain edema in the left hemisphere. Although CBF study is useful to predict the hyperperfusion syndrome, we cannot disregard the possibility of intracerebral hemorrhage after CAS for carotid artery stenosis when there is no evidence of hyperperfusion on postoperative CBF study.