We examined the severity of vascular inflammation in healthy individuals without hyperlipidemia but with elevated high-sensitivity C-reactive protein (hsCRP) using 18F-FDG PET, which is a promising imaging technique for the assessment of vascular inflammation within atherosclerotic plaques.
Methods: Vascular inflammation in the carotid arterial wall, represented as the target-to-background ratio (TBR), was measured using 18F-FDG PET in 120 healthy subjects without a history of cardiovascular diseases.
Results: Subjects with high hsCRP (≥2 mg/L) and low low-density lipoprotein cholesterol (LDL-C) (<130 mg/dL) levels had a significantly higher maximum TBR than did those with low hsCRP (<2 mg/L) and low LDL-C levels (<130 mg/dL) or low hsCRP (<2 mg/L) and high LDL-C levels (≥130 mg/dL) (1.29±0.13, 1.12±0.10, and 1.16±0.05, respectively), even though there were no significant differences in the carotid intima-media thickness. The maximum TBR values had the strongest positive correlation with hsCRP level among the various cardiovascular risk factors (r=0.68, P<0.01). However, other emerging inflammatory markers such as lipoprotein-associated phospholipase A(2) or monocyte chemoattractant protein-1 were not coherently associated with TBR values. Multiple stepwise regression analyses showed that hsCRP and diastolic blood pressure were independent decisive factors for maximum TBR, whereas age, diastolic blood pressure, and LDL-C were factors that determined the maximum intima-media thickness.
Conclusion: Vascular inflammation measured using 18F-FDG PET was increased in healthy individuals without hyperlipidemia but with elevated hsCRP.