biostudies-literatureUnknown36(1)van der Bie J<h4>Objectives</h4>This study investigated differences between aortic valve calcium (AVC) scores derived from true non-contrast (TNC) and virtual-non-contrast reconstructions acquired with photon-counting detector CT (PCD-CT) and the impact of ECG-phase variability on AVC scores.<h4>Materials and methods</h4>A hundred patients undergoing PCD-CT for transcatheter aortic valve implantation (TAVI) planning were retrospectively analyzed. Scores were computed using the Agatston methodology for TNC and virtual-non-iodine (VNI) reconstruction at scanner-selected optimal phase (best) and a fixed ECG-phase (300 ms). For VNI reconstructions, additional phases from 150 ms to 450 ms with 50 ms increments were reconstructed. AVC scores of TNC_best vs TNC₃₀₀, VNI_best vs TNC_best, VNI₃₀₀ vs TNC₃₀₀, and all VNI phases vs VNI_best were compared using Wilcoxon signed-rank tests. The agreement was assessed using scatter plots, Bland-Altman plots, and intra-class coefficients. AVC scores were also categorized based on the likelihood of severe aortic stenosis. Differences between reconstructions were evaluated as percentages (reclassification) and analyzed using Cohen's kappa coefficients.<h4>Results</h4>TNC_best and TNC₃₀₀ differed significantly (mean bias: 226; LoA: [-820, 1300]; p < 0.001, reclassification 17%). VNI_best vs TNC_best resulted in a mean bias of -512 (LoA: [-1900, 860]; p < 0.001) and reclassification of 17%. TNC₃₀₀ vs VNI₃₀₀ demonstrated a bias of -200 and reclassification of 14% (κ = 0.72). VNI reconstructions showed less variability across phases than the difference between TNC_best and TNC₃₀₀ (range, mean bias: 22-146).<h4>Conclusion</h4>VNI is a feasible alternative for AVC scoring but tends to overestimate compared to TNC. While phase-dependent variability in TNC underscores the need for standardization, further optimization of VNI is necessary for routine clinical use.<h4>Key points</h4>Question What is the performance of AVC score calculation from virtual non-contrast images with PCD-CT and the impact of the reconstructed ECG-phase? Findings VNI reconstructions tend to overestimate the scores compared to non-enhanced acquisitions. ECG phase significantly impacts AVC scores for non-enhanced acquisitions and VNI reconstructions. Clinical relevance Utilizing VNI reconstructions to calculate AVC scores might reduce radiation dose, and understanding the influence of ECG-phase on these scores might improve reliability.European radiology194-202https://www.ebi.ac.uk/biostudies/studies/S-EPMC12711920biostudies-literatureMultiphase aortic valve calcium scoring on true-non-contrast and calcium-preserving spectral reconstructions using dual-source photon-counting detector CT.PMC12711920van der Bie Jvan Straten MHirsch ABos Dvan Mieghem NMvan den Dorpel MMPBudde RPJfalseMultiphase aortic valve calcium scoring on true-non-contrast and calcium-preserving spectral reconstructions using dual-source photon-counting detector CT.<h4>Objectives</h4>This study investigated differences between aortic valve calcium (AVC) scores derived from true non-contrast (TNC) and virtual-non-contrast reconstructions acquired with photon-counting detector CT (PCD-CT) and the impact of ECG-phase variability on AVC scores.<h4>Materials and methods</h4>A hundred patients undergoing PCD-CT for transcatheter aortic valve implantation (TAVI) planning were retrospectively analyzed. Scores were computed using the Agatston methodology for TNC and virtual-non-iodine (VNI) reconstruction at scanner-selected optimal phase (best) and a fixed ECG-phase (300 ms). For VNI reconstructions, additional phases from 150 ms to 450 ms with 50 ms increments were reconstructed. AVC scores of TNC_best vs TNC₃₀₀, VNI_best vs TNC_best, VNI₃₀₀ vs TNC₃₀₀, and all VNI phases vs VNI_best were compared using Wilcoxon signed-rank tests. The agreement was assessed using scatter plots, Bland-Altman plots, and intra-class coefficients. AVC scores were also categorized based on the likelihood of severe aortic stenosis. Differences between reconstructions were evaluated as percentages (reclassification) and analyzed using Cohen's kappa coefficients.<h4>Results</h4>TNC_best and TNC₃₀₀ differed significantly (mean bias: 226; LoA: [-820, 1300]; p < 0.001, reclassification 17%). VNI_best vs TNC_best resulted in a mean bias of -512 (LoA: [-1900, 860]; p < 0.001) and reclassification of 17%. TNC₃₀₀ vs VNI₃₀₀ demonstrated a bias of -200 and reclassification of 14% (κ = 0.72). VNI reconstructions showed less variability across phases than the difference between TNC_best and TNC₃₀₀ (range, mean bias: 22-146).<h4>Conclusion</h4>VNI is a feasible alternative for AVC scoring but tends to overestimate compared to TNC. While phase-dependent variability in TNC underscores the need for standardization, further optimization of VNI is necessary for routine clinical use.<h4>Key points</h4>Question What is the performance of AVC score calculation from virtual non-contrast images with PCD-CT and the impact of the reconstructed ECG-phase? Findings VNI reconstructions tend to overestimate the scores compared to non-enhanced acquisitions. ECG phase significantly impacts AVC scores for non-enhanced acquisitions and VNI reconstructions. Clinical relevance Utilizing VNI reconstructions to calculate AVC scores might reduce radiation dose, and understanding the influence of ECG-phase on these scores might improve reliability.2026-01-01T00:00:00Z2026 Jan2026-06-06T04:37:27.05Z2026-05-25T03:12:07.752ZS-EPMC127119204069621810.1007/s00330-025-11814-8