Journal of Neurology, Neurosurgery, and Psychiatry 1987;50:988-996 Long-term noninvasive single photon emission computed tomography monitoring of perfusional changes after EC-IC bypass surgery V DI PIERO, G L LENZI, M COLLICE,t F TRIULZI,* P GERUNDINI,* D PERANI,* A R SAVI,* C FIESCHI, F FAZIO* From III Neurological Clinic, Department of Neurological Sciences, University of Rome, Department of Biomedical Technology, S. Raffaele Institute, University of Milan,* and Department of Neurosurgery, Niguarda Hospital,t Milan, Italy SUMMARY The rCBF was evaluated using 1-123 HIPDM and single photon emission computed tomography (SPECT) on 14 patients undergoing extracranial-intracranial (EC-IC) bypass surgery because of internal carotid artery (ICA) occlusion. Before surgery, all patients showed cortical areas of hypoperfusion over the affected cerebral hemisphere. Shortly after EC-IC bypass a rCBF in- crease was observed in six patients. However, at the 6 and 12 month follow-ups, with angiographic control of bypass patency, rCBF studies did not show any significant rCBF change. Long-term noninvasive tomographic monitoring of perfusion changes occurring after EC-IC bypass surgery failed to show a long-lasting improvement in perfusion. The prevention of new ischaemic episodes has been the main goal of extracranial-intracranial (EC-IC) bypass surgery. However, the results of the Inter- national EC-IC Bypass Study Group' indicate the failure of EC-IC bypass to reduce the recurrence of ischaemic stroke in comparison with conventional medical treatment. Nevertheless, the lack of data in this clinical study regarding physiological parameters, such as metabolism and perfusion, does not exclude the possibility, among the population examined, of the presence of subgroups of patients responsive to this revascularisation surgery.2 Previous studies have been devoted to the evalu- ation of the haemodynamic or metabolic effects of revascularisation within a short time after surgery. Results seemed to indicate short-term benefits from the procedure, with eventual neurological and psy- chological improvements3-9 parallelling the increase of perfusional and metabolic measurements. On the other hand, few reports have dealt with the evaluation of the long-term haemodynamic effects of EC-IC bypass surgery and data in the literature are highly debatable. Therefore, we have evaluated both the short and Address for reprint requests: V Di Piero MD, Department of Neuro- logical Sciences, V. le dell'Universita' N. 30, 00183 Roma, Italy. Received 12 August 1986. Accepted 23 September 1986. long term haemodynamic effects of EC-IC bypass surgery by means of single photon emission com- puted tomography (SPECT) and 1-123 HIPDM, a perfusion imaging agent developed by Kung et al'0 and utilised both in experimental and in clinical studies. 11 12 Patients and methods We studied 14 patients (13 males and one female) ranging from 42 to 73 years of age (mean age 56 8 + 8 9). All patients had had one or more episodes of cerebral ischaemia with occlusion of the internal carotid artery (ICA) on the same side of the symptomatic cerebral hemisphere. We excluded all patients with: (a) cerebral ischaemic epi- sodes affecting more than one vascular territory, (b) severe neurological deficits, (c) large or multiple areas of hypo- density at CT scan, (d) time interval from the last neuro- logical episode of less than 2 months. The study's protocol included: a full neurological evalu- ation, complete four-vessel cerebral angiography, cerebral CT scan and a regional cerebral blood flow (rCBF) study, all to be performed before (10 ± 14 days) and after (10 + 12 days) EC-IC bypass surgery. Only one patient (case No 10) had angiographic evidence of severe multiple lesions of the cerebral vessels. Further follow-up studies were obtained on 11 patients at 6 months (189 + 20 days) and on 10 at 12 months (498 + 77 days) after surgery. At each study, neurological exam- ination, cerebral CT scan and rCBF evaluation were re- 988 group.bmj.com on July 14, 2011 - Published by jnnp.bmj.com Downloaded from