Progressive Cortical Neuronal Damage and Extracranial-Intracranial Bypass Surgery in Patients with Misery Perfusion

Representative images of ¹¹C-flumazenil PET showing decreased BZR levels in a patient with right ICA occlusion and misery perfusion. The first PET study (first row) shows a mild decrease in the flumazenil-binding potential in the right (R) hemisphere with ICA occlusion and subcortical or deep white matter ischemic lesions (MR imaging) in which CBF is decreased and the oxygen extraction fraction is increased (misery perfusion). Follow-up 16 months later (second row) (15 months after bypass to the frontal branch of the MCA) shows relative decreases in FMZ-BP (arrow) and OEF, with increased CBF in the right hemisphere. 3D-stereotactic surface projection images and z score maps from the first (third row) and second (fourth row) examinations demonstrate a decrease in FMZ-BP in the right MCA distribution, especially in the parietotemporal lobe (arrow). The BZR index is increased from 71.6 to 100.8 between baseline and follow-up (arrow). An increased BZR index corresponds to a decreased BZR level, a decreased FMZ-BP level, and thus greater cortical neural damage. An increased BZR index was apparent in the cortical regions outside the territory of the recipient vessel, which suggested that cortical neural damage could not be ascribed to technical problems of the bypass anastomosis or postoperative hyperperfusion and might be associated with sustained hemodynamic impairment.