Imaging of Hypoxic–Ischemic Penumbra with 18 F-fluoromisonidazole PET/CT and Measurement of Related Cerebral Metabolism in Aneurysmal Subarachnoid Hemorrhage

This study aimed to characterize hypoxic, but salvageable, tissue imaged by 18 F-fluoromisonidazole ( 18 F-FMISO), combining with perfusion-computed tomography (PCT) for regional cerebral blood flow (rCBF) measurement and metabolism by microdialysis (MD) in aneurysmal subarachnoidal hemorrhage (SAH) patients. 18 F-FMISO positron-emission tomography (PET)/CT was performed within the period of possible vasospasm (day 6.8±3 after SAH) in seven SAH patients. In parallel, rCBF was determined within the MD region of interest (MD-ROI) ( n=5). The MD catheter was inserted into the brain parenchyma with highest risk for ischemia; extracellular levels of glutamate and energy metabolites were registered at time of PET and hourly for 10 days. Twelve-month outcome was evaluated. In asymptomatic patients ( n=3) no hypoxia was detected and glutamate levels were low (