Abstract 5029: Carotid Plaque Regression Following 6-Month Statin Therapy Assessed by 3T MRI: Comparison With Ultrasound Intima-Media Thickness

Abstract

Statin’s role in short-term plaque regression is unknown. 3T MRI has superior plaque volume (PV) measurement capacity compared to ultrasound intima-media thickness (IMT). We tested the hypothesis that carotid plaque progression is attenuated by 6 month statin therapy and this can be detected by MRI PV but not IMT. Methods : 15 subjects (68±3 years, 4F) with carotid atherosclerosis had carotid MRI (4 channel coil, resolution 0.3– 0.6×0.3– 0.6×2mm) and IMT assessed at baseline and 6 months post-statin treatment. T1, T2, proton density and time of flight images were obtained±12 mm from flow divider. PV and components were measured with Plaqueview software. Same day mean posterior IMT were measured by standard method. Observers were blinded to subject/scan order. Results : LDL changed from 90±7 to 78±7 mg/dL (p=NS). MRI PV decreased (1166±83 to 1084±102 mm 3 , p=0.007). Mean IMT was unchanged (1.14±0.07 vs. 1.14±0.07 mm, p=NS). Change in necrotic and hemorrhage volume correlated with MRI PV change (R=0.8, 0.7, all p<0.001), but not IMT change. In 8 subjects, plaque spatial distribution (6 quadrants) was analyzed (see figure ). Greatest thickness was seen opposite the flow divider (241–300°, p<0.01), a region not accessed by US IMT. Conclusions : In carotid disease, there was a measurable reduction in plaque burden following short-term statin treatment using 3T MRI that was not seen with US IMT. The heterogenous spatial distribution of plaque supports use of volumetric measurement for serial studies. 3T MRI may be useful to assess treatment efficacy, reduce number of subjects needed and be a better imaging tool to assess effects of novel therapies for carotid atherosclerosis in clinical trials.