Quantification of non-calcified coronary atherosclerotic plaques with dual-source computed tomography: comparison with intravascular ultrasound

Background The quantification of non-calcified coronary plaques using multidetector computed tomography has not been extensively investigated. Objective To evaluate the ability of dual-source computed tomography (DSCT) to quantify non-calcified plaque volumes using intravascular ultrasound (IVUS) as the standard of reference. Methods The datasets of 70 patients with suspected or known coronary artery disease who underwent DSCT (330 ms gantry rotation, 2x64x0.6 mm collimation, 60-90 ml contrast agent) were analysed before invasive coronary angiography, with IVUS performed as part of the diagnostic procedure. 100 individual non-calcified coronary atherosclerotic plaques (one to three plaques per patient) with suitable fiducial markers were matched and selected for plaque volume measurements using manual segmentation. Only DSCT datasets with good or excellent image quality were considered for analysis. Results Intra and interobserver variability for plaque volume measurements by DSCT were 6+/-5% and 11+/-7%, respectively. Mean total plaque volume by DSCT was 89666 mm(3) (range 14-400 mm(3)). Mean total plaque volume by IVUS was 90+/-73 mm(3) (range 16-409 mm(3)). The mean difference between DSCT and IVUS was 1+/-34 mm(3) (range -131-85 mm(3)). Despite the good correlation for plaque volume measurements (r=0.89, p<0.001), agreement between the two methods was only modest (Blande-Altman limits of agreement -67 to +65 mm(3)). Conclusions Non-calcified plaque volumes as determined by DSCT yielded good correlation but only modest agreement in comparison with IVUS.