Quantitative assessment of stenosis severity and atherosclerotic plaque composition using 256-slice computed tomography

To quantitatively estimate lumen narrowing and to assess the volume and composition of atherosclerotic plaque with 256-slice computed tomography angiography (CTA), using conventional quantitative coronary angiography (QCA) as the gold standard. Twenty-seven consecutive patients with suspected coronary artery disease (CAD) underwent 256-slice CTA and subsequent coronary angiography within 4 weeks. Quantification of lumen narrowing was performed on curved multiplanar reformatted CTA images, in identical projections to those used for QCA. Atherosclerotic plaque volume and composition were assessed by using commercially available software. The overall correlation between the stenosis severity by QCA compared with CTA was high (r 2 = 0.79, p < 0.001). For the detection of ≥50% and ≥75% diameter lesions, CTA yielded high sensitivity, specificity and accuracy (86%, 95% and 90%; and 89%, 100% and 96%, respectively), using QCA as the standard reference. Furthermore, assessment of atherosclerotic plaque yielded highly reproducible results (inter-observer and intra-variability of 13% and 9%, respectively, for the assessment of plaque volume, and high agreement between observers (κ = 0.86) for the differentiation between non-calcified, mixed and calcified plaque). Clinically indicated 256-slice CT angiography in symptomatic patients can aid both quantification of lumen narrowing and evaluation of atherosclerotic plaque, with high reproducibility. (orig.)