Background: The quantification of noncalcified coronary plaques using multidetector computed tomography has not been extensively investigated.
Objective: To evaluate the ability of Dual Source CT (DSCT) to quantify noncalcified plaque volumes using intravascular ultrasound (IVUS) as the standard of reference.
Methods: We analyzed the datasets of 70 patients with suspected or known coronary artery disease who underwent DSCT (330 ms gantry rotation, 2 x 64 x 0.6 mm collimation, 60 – 90 mL contrast agent) prior to invasive coronary angiography, with IVUS performed as part of the diagnostic procedure. One hundred individual noncalcified coronary atherosclerotic plaques (1 to 3 plaques per patient) with suitable fiducial markers were matched and selected for plaque volume measurements using manual segmentation. Only DSCT data sets 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 89 ± 66 mm3 (range, 14 to 400 mm3). Mean total plaque volume by IVUS was 90 ± 73 mm3 (range, 16 to 409 mm3). The mean difference between DSCT and IVUS was 1 ± 34 mm3 (range, -131 to 85 mm3). Despite the good correlation for plaque volume measurements (r = 0.89, P < 0.001), agreement between the two methods was only modest (Bland Altman limits of agreement, -67 to +65 mm3).
Conclusions: Noncalcified plaque volumes as determined by DSCT yielded good correlation but only modest agreement in comparison to IVUS.