Non-focal vascular FDG-uptake precedes cerebrovascular events

Objectives Carotid uptake of FDG is considered a marker of vascular inflammation and thus plaque unstability. We aim to determine if carotid FDG uptake assessed by PET/CT can predict cerebrovascular events months to years later.

Methods We retrospectively identified patients from our institution with a FDG-PET/CT and a subsequent diagnosis of a cerebrovascular event (apoplexia cerebri or transient ischemic attack). The patients were identified through the National Patient Register. Known cardiovascular risk factors and demographics were extracted from the medical records. FDG uptake was retrospectively assessed in the carotid arteries using the blood-pool-corrected target-to-background ratio (TBR).

Results We included 74 patients. The patents had a typical cardiovascular-risk profile with 29 (39%) being men, mean age 64 (±11.1) years, and 88% were current or former smokers. The typical indication for the FDG-PET/CT was known or suspected cancer (90%). The median time from FDG-PET to the cerebrovascular event was 13 months (IQR 4.7-27.7). 42% of the patients had high carotid FDG-uptake (TBR>1.8). However, FDG-uptake in the carotid artery ipsilateral to the cerebrovascular event (1.8 ±0.6) was similar to the contralateral carotid artery (1.7 ±0.5, p=0.6) as shown in the figure. There was a high correlation between FDG-uptake in the two carotid arteries (r=0.8, p<0.001). We found no indication that time from PET to event influenced the uptake difference in the two arteries (r=-0.1, p=0.3).

Conclusions Our data indicate that unilateral cerebrovascular insults are not preceded by ipsilateral increased FDG-uptake but rather a bilateral increase in FDG-uptake. $$graphic_40F8CD8F-D761-43CE-9CA9-0ED87CB010FE$$