Diagnostic improvements of calcium-removal image reconstruction algorithm using photon-counting detector CT for calcified coronary lesions

•Coronary calcification is associated with low diagnostic CT angiography specificity.•Calcium-removal imaging with PCD-CT improved the diagnostic accuracy.•PCD-CT may be useful for evaluating calcified segments of the coronary lumen. To investigate the diagnostic performance of a calcium-removal image reconstruction algorithm with photon-counting detector-computed tomography (PCD-CT), a technology that hides only the calcified plaque from the spectral data in coronary calcified lesions. This retrospective study included 17 patients who underwent PCD-coronary CT angiography (CCTA) with at least one significant coronary stenosis (≥50 %) with calcified plaque by CCTA and invasive coronary angiography (ICA) performed within 60 days of CCTA. A total of 162 segments with calcified plaque were evaluated for subjective image quality using a 4-point scale. Their calcium-removal images were reconstructed from conventional images, and both images were compared with ICA images as the reference standard. The contrast-to noise ratios for both images were calculated. Conventional and calcium-removal images had a subjective image quality of 2.7 ± 0.5 and 3.2 ± 0.9, respectively (p