Arterial remodeling of advanced basilar atherosclerosis

Abstract

There are limited studies on wall imaging of human basilar artery (BA). Our aim was to investigate remodeling mode of advanced BA atherosclerosis using 3-T MRI. Thirty-two consecutive symptomatic patients with atherosclerotic BA stenosis >or=70% were imaged with a 3-T magnetic resonance scanner. Proton density-weighted (PDW) cross-sectional images with submillimeter voxel size were obtained. The vessel area (VA) and lumen area (LA) at the maximal lumen narrowing (MLN) site and reference site were measured. Intraobserver and interobserver variability was determined by intraclass correlation coefficient (ICC). Wall area (WA) was estimated by VA - LA. Plaque size (PS) was estimated by WA at MLN site--reference WA. Percent plaque burden was calculated as (PS/VA at MLN site) x 100%. Remodeling index (RI) was the ratio of VA at MLN site to reference VA. RI >or=1.05 was defined as positive remodeling (PR) and RI <1.05 as non-PR. Measurements of cross-sectional BA images were available in 30 of 32 patients. Intraobserver or interobserver variability was small, with ICC ranging from 0.955 to 0.996. The mean RI of the 30 patients was 1.2 +/- 0.4. PR was found in 19 (63.3%) patients and non-PR in 11 (36.7%) patients. Compared with the non-PR group, the PR group had greater PS (15.0 +/- 9.3 mm(2) vs 6.4 +/- 3.9 mm(2), p = 0.007) and greater percent plaque burden (50.5 +/- 9.9% vs 28.5 +/- 12.7%, p < 0.0001). 3-T high-resolution PDW imaging is a reproducible tool for measuring BA dimensions. In patients with advanced BA atherosclerosis, PR lesions are more frequently observed and contain larger plaques than non-PR lesions.