Objectives: The aim of the study was to depict regional cerebral blood flow (rCBF) during carotid cross clamping using 99mTechnetium-hexamethylpropylene amine oxime (TcHMPAO). This tracer rapidly passes the blood-brain barrier and is retained for hours in the brain tissue. Injecting TcHMPAO during surgery and performing single photon emission computer tomography (SPECT) scanning shortly after the operation thereby pictures rCBF at the time of injection.
Design: Ongoing prospective study.
Settings: Departments of Vascular Surgery, Neurology and Anaesthesiology, University Hospital, Rigshospitalet, Copenhagen, Denmark.
Material: 15 patients who during a period of 4 months underwent carotid endarterectomy.
Chief outcome measures: Prior to surgery rCBF was determined using 133Xe and SPECT. Intraoperatively stump pressure was measured and a bolus of TcHMPAO was injected for later SPECT measurement.
Main results: We found a significant correlation between stump pressure and enhancement of side-to-side asymmetry in rCBF due to carotid cross clamping. Pronounced variations were seen in which regions were deprived of perfusion during clamping.
Conclusion: TcHMPAO allows tomographic assessment of CBF during carotid surgery. This method may serve as a reference tool in future research on intraoperative cerebral haemodynamics.