PET neuroreceptor imaging as predictor of severe cerebral ischemic insult

Abstract

Measurement of the adenosine Ai receptor (Al-R) with positron emission tomography (PET) using a newly developed positron Iigand, [1 -methyl-11 C]8-dicyclopropylmethy 1-1 -methyl-3- propylxanthine (MPDX), were performed in a cat middle cerebral artery (MCA) occlusion and reperfusion. Eighteen adult cats underwent PET measurement of; 1) cerebral blood flow (CBF), 2) Al- R, 3) central benzodiazepine receptor (BDZ-R) and 4) glucose metabolism with 5O labeled water, MPDX, 11C-flumazenil (FMZ) and 18F-fluorodeoxyglucose (FDG), respectively. The CBF, Al-R, BDZ-R and FDG uptake were serially measured after 60 min occlusion of MCA in this order. MPDX binding and FMZ binding, but not CBF and FDG uptake, were significantly reduced in the groups with severer ischemic insult than in the groups with no or milder insults. Of the two receptor ligands, the reduction rate of the MPDX binding to Al-Rs was larger in a group that caused fatal ischemic insult. The newly developed PET in vivo imaging technique using MPDX was suitable in evaluating the function of adenosine and Al- Rs in relation to cerebral ischemia. © Springer-Verlag 2003.