Abstract 1728: Inflammatory Activity is Associated with a Reduction in Fibrous Cap Thickness: A Dynamic Contrast-Enhanced Magnetic Resonance Imaging Study
Purpose: Atherosclerosis is an inflammatory disease. An elevated transfer constant Ktrans, measured by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), was previously shown to be strongly associated with histological evidence of carotid plaque inflammation, namely neovasculature and macrophage infiltration. The aim of this prospective, serial MRI study was to test the hypothesis that plaques with elevated Ktrans at baseline will show a reduction in fibrous cap (FC) thickness during follow-up.
Methods: 57 consecutive participants with 15–79% stenosis were imaged at baseline and 1.5 yrs with multi-contrast carotid MRI and DCE-MRI at 1.5T. Two reviewers blinded to time point reached a consensus interpretation of each matched axial location. Using a semi-automated image analysis tool, the distance of the lipid-rich necrotic core from the lumen was determined and used as an estimate of FC thickness. Only arteries exhibiting an LRNC with an unruptured FC thicker than the image resolution (0.62 mm) were included. Ktrans was determined from the baseline DCE-MRI for each artery. The relationship between Ktrans and changes in the FC after 1.5 yrs was determined by Spearman’s correlation coefficient (r).
Results: 47 arteries from 38 subjects were identified with a thick FC. There was a significant inverse relationship (Fig. 1⇓) between Ktrans and change in FC thickness (r =−0.372, p =0.01).
Conclusion: Carotid plaques with evidence of increased inflammatory activity, as measured by DCE-MRI, are associated with a decrease in FC thickness during follow-up. DCE-MRI, may be an effective tool for determining plaques at risk for FC destabilization by inflammatory activity.