Changes in atherosclerotic plaque composition assessed by MRI in the superficial femoral artery with two years of lipid lowering therapy

Methods 43 patients with PAD (age 63±9, ABI 0.72±0.14) were imaged at baseline and annually for 2 years after beginning lipid lowering therapy. Twenty statin-naive patients were randomized to simvastatin (S, n=11) or simvastatin +ezetimibe (S+E, n=9). Patients already on statins not at LDL cholesterol goal had open-label ezetimibe added (E, n=23). MRI of a single slice of the SFA was performed on Siemens Avanto 1.5T scanner with a proton-density weighted image (TR 1100ms, TE 7.6ms), T1-W image (TR 700ms, TE 7.7ms) and T2-W image (TR 2000ms, TE 85ms), using slice thickness 3mm, matrix 256x256 pixels, FOV 150mm, flip angle 180°. Image location was repeated over time using the distance of the imaged slice from the bifurcation of the common femoral artery. Image quality scale from 1-4 was used to grade the images, excluding 6 studies for score ≤ 2 in more than one image. VesselMASS software was used to measure plaque components (lipids, calcium, loose matrix and fibrous tissue) based on published critieria for appearance on T1/T2/PDW images. Changes in parameters were assessed with ANOVA repeated measures model and correlation with two-tailed Pearson.