18 f-fdg pet/ct for the quantification of inflammation in large carotid artery plaques

There is currently no consensus on the methodology for quantification of 18f-fdg uptake in inflammation in atherosclerosis. in this study, we explore different methods for quantification of 18f-fdg uptake in carotid atherosclerotic plaques and correlate the uptake values to histological assessments of inflammation. forty-four patients with atherosclerotic stenosis ≥70% of the internal carotid artery underwent 18f-fdg pet/ct. maximum standardized uptake values (suvmax) from all plaque-containing slices were collected. suvmax for the single highest and the mean of multiple slices with and without blood background correction (by subtraction (csuv) or by division (target-to-background ratio (tbr)) were calculated. following endarterectomy 30 plaques were assessed histologically. the length of the plaques at ct was 6-32 mm. the 18f-fdg uptake in the plaques was 1.15-2.66 for uncorrected suvs, 1.16-3.19 for tbrs, and 0.20-1.79 for csuvs. there were significant correlations between the different uptake values (r = 0.57-0.99, p < 0.001). methods with and without blood background correction showed similar, moderate correlations to the amount of inflammation assessed at histology (r = 0.44-0.59, p < 0.02). in large stenotic carotid plaques, 18f-fdg uptake reflects the inflammatory status as assessed at histology. increasing number of pet slices or background correction did not change the correlation.