Subacute ischemic stroke is associated with focal 11C PiB positron emission tomography retention but not with global neocortical Aβ deposition.

BACKGROUND AND
PURPOSE: Conflicting evidence exists as to whether focal cerebral ischemia contributes to cerebral amyloid deposition. We aimed to look at Aβ deposits, detected by N-methyl-2-(4'-methylaminophenyl)-6-hydroxybenzothiazole (PiB) positron emission tomography, in patients with recent ischemic stroke. Specifically, we hypothesized that patients with recent ischemic stroke have higher local and neocortical PiB positron emission tomography retention and that this may be associated with major vascular risk factors.
METHODS: Ischemic stroke patients were studied using PiB positron emission tomography within 30 days and compared to age-matched controls. Distribution volume ratio maps were created using Logan graphical analysis with the cerebellar cortex as a reference.
RESULTS: Among the 21 ischemic stroke patients (median age, 76 years; interquartile range, 68-77), the ipsilateral peri-infarct region PiB retention was higher compared to the contralateral mirror region, with a PiB distribution volume ratio difference of 0.29 (95% CI, 0.2-0.44; P=0.001) at median 10 (interquartile range, 7-14) days after stroke. Two patients also had higher PiB retention within the infarct compared to the contralateral side. There was no difference in the neocortical PiB retention elsewhere in the brain among ischemic stroke patients compared with 22 age-matched normal controls (P=0.22). Among the risk factors in the ischemic stroke patients, diabetes was associated with a higher neocortical PiB retention (Spearman Rho=0.48; 95% CI, 0.28-0.72).
CONCLUSIONS: PiB retention was higher in the peri-infarct region among patients with recent ischemic stroke. This did not translate into a higher global neocortical PiB retention except possibly in patients with diabetes. The cause of the focal PiB retention is uncertain and requires further investigation.