2126 Saphenous vein graft atherosclerotic plaque quantification utilizing magnetic resonance imaging and multidetector computed tomography: a comparison with intravascular ultrasound

Abstract

Methods Sequential patients (n = 22) undergoing coronary angiography with anginal symptoms and significant saphenous vein graft lesions were enrolled. All patients had IVUS, MDCT (16-detector) and MRI using black-blood T1weighted imaging (1.5 T) performed. Cross-sectional images from IVUS and MDCT were analysed at 1 mm intervals along the entire length of the lesion. MRI images were obtained and analysed at 5 mm intervals. The sum of the plaque areas on these images gave the lesion volume. The MDCT and MRI images were analysed by two independent investigators. Spearman's correlation and BlandAltman plots were used where appropriate. Results MRI data were analysed for 18 patients (n = 19 lesions) as 3 patients were unable to finish their scans and one patient's scan was degraded by artefact. The mean age of the SVGs was 13.95 years ( ± 4.41 years). The interobserver variability as determined by coefficient of variance for assessing plaque volume for MDCT and MRI was 3.6% and 9.9% respectively. The correlation between MDCT and IVUS was better in mean luminal area (r = 0.87; p < 0.001) than mean vessel wall area (r = 0.77; p < 0.001). In contrast, MRI and IVUS correlation was better in vessel wall area (r = 0.77; p < 0.001) than luminal area (r = 0.59; p = 0.008). Spearman's correlation for plaque volume was better for MRI and IVUS (rs = 0.97; p < 0.001) compared to MDCT and IVUS (rs = 0.85; p < 0.001). However, Bland-Altman plots (Figure 1) show plaque volumes by MDCT to be closer to IVUS (differences of mean = 186.9 mm3; SD = 239.1) compared to MRI and IVUS (differences of mean = 437.5 mm3; SD = 407.9).