CORTICAL BLOOD-FLOW AND COGNITION AFTER EXTRACRANIAL-INTRACRANIAL BYPASS IN A PATIENT WITH SEVERE CAROTID OCCLUSIVE LESIONS - A 3-YEAR FOLLOW-UP-STUDY

The long-term effect of extra-intracranial arterial bypass on cerebral circulation was examined. Cortical blood flow and cognitive ability w ere evaluated pre- and up to 3 years post-bypass in a 58-years-old man with severe carotid occlusive lesions, who presented with 3 transient cerebral ischaemic attacks which resulted in mental deterioration ove r 3 years. Regional cerebral blood flow (rCBF) was evaluated pre- and up to 33 months post-bypass by Iodine-123 N-isopropyl-p-iodoamphetamin e (IMP) single-photon emission CT (SPECT). Mental abilities were evalu ated before and up to 33 months after surgery by the Hasegawa's dement ia rating scale (HDRS). Pre-operatively, cerebral angiography showed l eft carotid siphon occlusion and hypoplastic stenosis of left anterior cerebral artery with collaterals from the anterior communicating arte ry. CT and MRI showed left temporo-parietal borderzone infarction and an enhanced T 1 lesion by gadolinium-DTPA at left periventriculum. rCB F showed extensive hypoperfusion in left anterior-parieto-temporal-cor tex. HDRS scores deteriorated apparently on days 3, 5, which recovered gradually on days 8, 10, 75 after onset of mental deterioration. A by pass was performed 4 months after onset. rCBF showed gradual recovery in the left anterior-parietal cortex up to 33 months after bypass. Sem iquantitative rCBF showed gradual decreases of regional asymmetry afte r the bypass. HDRS scores returned to their maximum up to 37 months af ter onset. Three-year follow-up shows improved cortical rCBF and cogni tion after the bypass.