Interscan reproducibility of computed tomography derived coronary plaque volume measurements.

Background: Coronary computed tomography angiography (CCTA) enables detailed quantification and characterization of coronary atherosclerotic plaques, offering diagnostic and prognostic value. Interscan reproducibility studies on plaque volume measurements are limited. This study aims to assess the interscan reproducibility of coronary plaque quantification and the implications of clinical and technical characteristics on interscan reproducibility.

Methods: CCTA was performed twice in 101 patients with known coronary artery disease at a 1-h interval. The scans were conducted using identical CCTA acquisition protocols. Coronary plaque volumes were quantified using a semi-automated software and performed on a per-lesion, per-vessel, and per-patient level.

Results: Median plaque volumes were comparable between the first and second CCTA scan. Interscan correlation was high for total plaque (TP), non-calcified plaque (NCP), and calcified plaque (CP) across all analyses (Pearson's coefficient 0.93-0.99), but lower for low-density non-calcified plaque (LD-NCP) volume measurements (Pearson's coefficient 0.74-0.77). Bland-Altman analyses demonstrated higher interscan agreement on a per-patient level compared to on per-vessel and per-lesion level. Interscan reproducibility on CP volumes was affected by CT image quality with narrower LoA in scans with the highest image quality score (p ​= ​0.003), or lowest image reconstructive iteration level (p ​< ​0.001). Limits of agreement were significantly narrower for TP, NCP, and CP volumes in LAD-lesions and vessels compared to non-LAD lesions and vessels (p ​≤ ​0.001).

Conclusion: Overall reproducibility of repeated CCTA derived plaque measurements by a semi-automated software was modest, and was influenced by image quality, image reconstruction settings, and lesion location.