Quantification and characterisation of coronary artery plaque volume and adverse plaque features by coronary computed tomographic angiography: a direct comparison to intravascular ultrasound.

OBJECTIVE: We evaluated the performance of manual measures of coronary plaque volumes and atherosclerotic plaque features from coronary CT angiography (CTA), using intravascular ultrasound (IVUS) as the reference.
METHODS: Thirty individual coronary plaques with suitable fiduciary markers were identified. Plaque volumes on coronary CTA were manually quantified by two observers and compared to IVUS plaque volumes as interpreted by an independent laboratory. The presence of adverse plaque characteristics-low attenuation plaque (LAP), positive remodelling (PR) and spotty calcification (SC)-on coronary CTA was evaluated and compared to IVUS.
RESULTS: High correlation in plaque volumes was detected between observers (r = 0.94, P < 0.0001; 95 % limits of agreement <48.7 mm(3), bias 6.6 mm(3)). Excellent correlation (r = 0.95, P < 0.0001) was noted in plaque volume between independent observers and IVUS (95 % limits of agreement <40.6 mm(3), bias -4.4 mm(3)) and did not differ from IVUS (105.0 ± 56.7 vs. 109.4 ± 60.7 mm(3), P = 0.2). The frequency of LAP (10 % vs. 17 %), PR (7 % vs. 10 %) and SC (27 % vs. 33 %) was similar between coronary CTA and IVUS (all P = NS).
CONCLUSIONS: Plaque volume on coronary CTA determined by manual methods demonstrates high correlation and modest agreement to IVUS. Further, coronary CTA demonstrates high accuracy for the identification of adverse plaque characteristics, including LAP, PR and SC. KEY POINTS: • Coronary CT angiography is a non-invasive test that enables coronary plaque assessment • Plaque quantification by coronary CT angiography correlates well with intravascular ultrasound findings • Coronary CT angiography can identify adverse plaque characteristics.