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 (<10 mmol/L), whereas symptomatic patients had higher glutamate concentrations (P<0.001). Increased (18)F-FMISO uptake within the MD-ROI (n=3) was related to higher glutamate levels, while rCBF was above the ischemic range. Hypoxia (increased (18)F-FMISO uptake) was present in symptomatic patients and associated with relevant metabolic derangement of extracellular glutamate levels, whereas energy metabolism and rCBF were preserved. This technique has the potential to improve our understanding of the role of cellular hypoxia in aneurysmal SAH.
Sarrafzadeh
Asita S
AS
Department of Neurosurgery, Charité-Universitätsmedizin Berlin, Berlin, Germany. asita.sarrafzadeh@charite.de
Nagel
Alexandra
A
Czabanka
Marcus
M
Denecke
Timm
T
Vajkoczy
Peter
P
Plotkin
Michail
M
D000368:Aged; D001923:Brain Chemistry / Q000502:physiology; D002545:Brain Ischemia / Q000000981:diagnostic imaging*; D002543:Cerebral Hemorrhage / Q000000981:diagnostic imaging*; D002560:Cerebrovascular Circulation / Q000502:physiology; D005260:Female; D023261:Glasgow Outcome Scale; D005947:Glucose / Q000378:metabolism; D018698:Glutamic Acid / Q000378:metabolism; D006801:Humans; D002534:Hypoxia, Brain / Q000000981:diagnostic imaging*; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D008920:Misonidazole / Q000031:analogs & derivatives*; D009422:Nervous System Diseases / Q000000981:diagnostic imaging / Q000209:etiology; D010477:Perfusion; D010865:Pilot Projects; D049268:Positron-Emission Tomography; D011446:Prospective Studies; D019275:Radiopharmaceuticals; D013345:Subarachnoid Hemorrhage / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed; D020301:Vasospasm, Intracranial / Q000000981:diagnostic imaging
D019275:Radiopharmaceuticals; C031843:fluoromisonidazole; D018698:Glutamic Acid; D008920:Misonidazole; D005947:Glucose