Objective: We investigated early postoperative hemodynamic and metabolic values using positron emission tomography (PET) scanning in subarachnoid hemorrhage (SAH) patients treated with clipping or coiling, and evaluated usefulness of PET studies in predicting late ischemic events and neurological outcome in SAH patients.
Methods: We examined 14 SAH patients treated with neurosurgical clipping (CLIP group) and 16 patients treated with endovascular coiling (COIL group). Cerebral blood flow (CBF), cerebral metabolic rate for oxygen (CMRO2), and oxygen extraction fraction (OEF) were determined using 15O-PET scanning about 8.5 days after SAH.
Results: 1) Mean regional CBF (rCBF) in the middle cerebral artery (MCA) territory was significantly higher in CLIP group compared with COIL group; regional CMRO2 (rCMRO2) and regional OEF (rOEF) were also higher. Four clipped patients showed true hyperemia in the MCA territory; none of the coiled patients showed hyperemia. 2) Surgical intervention significantly decreased mean rCMRO2 and rOEF in the operated frontal lobe compared with the unoperated side. 3) Nine of 30 patients (40%) developed subsequent clinical vasospasm after SAH. Significant differences between the spasm group and non-spasm group were not observed in the MCA territory before vasospasm.
Conclusion: A wide range of cerebral perfusion patterns including hyperemia were found in the CLIP group. Surgical manipulation of the brain significantly reduced oxygen metabolism in the operated frontal lobe. PET data alone may not have independent prognostic value for detecting delayed cerebral ischemia or in predicting neurological outcome.