PET EVALUATION OF CEREBRAL HEMODYNAMICS IN OCCLUSIVE CEREBROVASCULAR-DISEASE PRESURGERY AND POSTSURGERY

We studied cerebral blood flow (CBF), oxygen extraction fraction (OEF) , transit time (TT) and hemodynamic reserve capacity using acetazolami de (ACZ) in both the pre-and postoperative states, and evaluated the e ffect of surgery on the cerebral hemodynamics, Methods: Twelve patient s with a unilateral occlusive cerebral artery were studied. Among them , seven patients had extracranial-intracranial (EC-IC) bypass surgery, while the remaining five patients had carotid endarterectomies. The C BF was measured using the O-15-water bolus injection method in a resti ng state, 5 and 20 min after intravenous ACZ (1 g), while the OEF and TT were measured by the O-15 steady state method. The values of these parameters were obtained by regions of interest set over the cerebral hemisphere on both sides, and which then were compared between the pre -and postoperative states using the paired Student's t-test. Results: The t values were 1.36 (CBF at rest), 2.97 (CBF at 5 min after intrave nous ACZ), 1.40 (CBF at 20 min after intravenous ACZ), 2.00 (OEF) and -0.86 (TT) on the surgical side, and -0.16, 0.21, 0.22, -0.47 and 0.61 on the nonsurgical side, respectively. The t values of the ACZ respon se (% increase in CBF) were 3.07 (5 min after intravenous ACZ) and 0.7 2 (20 min) on the surgical side, and 1.03 and 0.90 on the nonsurgical side, respectively. A significant change was observed only in the CBF studies 5 min after intravenous ACZ. Conclusion: PET can demonstrate s ignificant cerebral hemodynamic change after surgery, especially in CB F measurement 5 min after intravenous ACZ, and may therefore be useful for evaluating cerebral hemodynamics pre-and postsurgery.