[1-C-11]Octanoate as a PET tracer for studying ischemic stroke: Evaluationin a canine model of thromboembolic stroke with positron emission tomography

Octanoate is taken up by the brain and converted in astrocytes to glutamine through the TCA cycle after beta-oxidatiun. Consequently, [1-C-11]octanoat e might serve as a useful positron emission tomography (PET) probe for stud ying cerebral oxidative metabolism and/or astroglial functions. The present study attempted to evaluate the utility of using [1-C-11]octanoate as a PE T tracer for imaging and evaluating the pathophysiology of ischemic stroke, We used a canine model of thromboembolic stroke. Five male beagle dogs wer e implanted with an indwelling catheter in the left internal carotid artery A single autologous blood clot was injected into the left internal carotid artery through the catheter, The brain distribution of [1-C-11]octanoate a nd cerebral blood Row (CBF) were determined 24 h after insult using a high resolution PET scanner Post mortem brain regions unstained with 2,3,5-triph enyltetrazolium chloride (TTC) were defined as infarcts. In the region of a n infarct, accumulation of [1-C-11]octanoate decreased concurrently. with C BF reduction. In contrast, normal accumulation of [1-C-11]octanoate was obs erved in ischemic but vital regions, suggesting that an increased accumulat ion of [1-C-11]octanoate relative to CBF takes plate in these regions. In c onclusion, [1-C-11]octanoate accumulated in ischemic hut vital regions, ind icating that [1-C-11]octanoate is a potentially useful PET tracer for imagi ng and evaluating the pathophysiology of ischemic stroke.