Perivascular Fat Density and Contrast Plaque Enhancement: Does a Correlation Exist?

BACKGROUND AND PURPOSE: Inflammatory changes in the fat tissue surrounding the coronary arteries have been associated with coronary artery disease and high-risk vulnerable plaques. Our aim was to investigate possible correlations between the presence and degree of perivascular fat density and a marker of vulnerable carotid plaque, namely contrast plaque enhancement on CTA. MATERIALS AND METHODS: One-hundred patients (76 men, 24 women; mean age, 69 years) who underwent CT angiography for investigation of carotid artery stenosis were retrospectively analyzed. Contrast plaque enhancement and perivascular fat density were measured in 100 carotid arteries, and values were stratified according to symptomatic (ipsilateral-to-cerebrovascular symptoms)/asymptomatic status (carotid artery with the most severe degree of stenosis). Correlation coefficients (Pearson rho product moment) were calculated between the contrast plaque enhancement and perivascular fat density. The differences among the correlation rho values were calculated using the Fisher r-to-z transformation. Mann-Whitney analysis was also calculated to test differences between the groups. RESULTS: There was a statistically significant positive correlation between contrast plaque enhancement and perivascular fat density (rho value = 0.6582,Pvalue = .001). The correlation was stronger for symptomatic rather than asymptomatic patients (rho value = 0.7052,Pvalue = .001 versus rho value = 0.4092,Pvalue = .001). CONCLUSIONS: There was a positive association between perivascular fat density and contrast plaque enhancement on CTA. This correlation was stronger for symptomatic rather than asymptomatic patients. Our results suggest that perivascular fat density could be used as an indirect marker of plaque instability.