Key result
Dual-energy CT virtual non-contrast images show ~92% concordance with true non-contrast for severe AS.
Why the study?
With the growing use of delayed DECT for extracellular volume assessment, the accuracy of CAC and AVC quantification on VNC images derived from delayed DECT needed assessment.
Does virtual non-contrast imaging from delayed DECT accurately quantify coronary and aortic valve calcification compared to true non-contrast imaging in patients with severe aortic stenosis?
Observational (n=88)
Blinded readers
No
Does virtual non-contrast imaging from delayed DECT accurately quantify coronary and aortic valve calcification compared to true non-contrast imaging in patients with severe aortic stenosis?
Effect estimate: LCC 0.952 (95% CI 0.929-0.968)
Absolute Event Rate: 363% vs 470.1%
p-value: p=<0.001
Virtual non-contrast images from delayed DECT demonstrate strong agreement with true non-contrast images for aortic valve and coronary calcification scoring, potentially reducing the need for true non-contrast acquisition in pre-TAVR assessment.
May allow omission of true non-contrast scans in pre-TAVR CT protocols; leaves open whether virtual non-contrast reliably replaces true non-contrast in routine practice.
With the growing use of delayed dual-energy computed tomography (DECT) imaging for extracellular volume assessment, this study aimed to assess the accuracy of coronary artery calcium (CAC) and aortic valve calcification (AVC) quantification in virtual non-contrast (VNC) images derived from delayed DECT images. Eighty-eight patients undergoing pre-transcatheter aortic valve replacement (TAVR) cardiac CTA with DECT were retrospectively enrolled. We compared CAC score (CACS), CAC volume, AVC score (AVCS), and AVC volume between true non-contrast (TNC) and VNC images. VNC images were created by subtracting iodine from delayed CT angiography using commercial post-processing software. Concordance for the likelihood of severe aortic stenosis (AS) between TNC and VNC was assessed using guideline-based AVCS thresholds: men > 3,000 AU, women > 1,600 AU (highly likely); men > 2,000 AU, women > 1,200 AU (likely). CACS was lower in VNC than TNC (363.0 [13.7-1,154.0] AU vs. 470.1 [46.8-1,569.9] AU, p < 0.001), but the correlation was excellent (r = 0.966). No significant difference between VNC and TNC was observed in AVCS (959.5 [321.2-2,475.0] AU vs. 1,079.6 [492.2-2,329.4] AU, p = 0.521), with strong correlation (r = 0.966). Application of a correction factor (1.1-fold) improved agreement between VNC- and TNC-derived CACS (weighted κ = 0.839 to 0.869). Diagnostic concordance for severe AS between VNC and TNC was 92.1% (weighted kappa = 0.785) at the "highly likely" threshold and 97.7% (weighted kappa = 0.952) at the "likely" threshold. Delayed VNC images from DECT demonstrate strong agreement with TNC images for CACS and AVCS, suggesting that delayed VNC could potentially reduce the need for TNC acquisition in pre-TAVR assessment.
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Fujito et al. (2026) conducted an observational in Severe aortic stenosis (n=88). Virtual non-contrast (VNC) images from delayed dual-energy CT vs. True non-contrast (TNC) images was evaluated on Coronary artery calcium score (CACS) (LCC 0.952, 95% CI 0.929-0.968, p=<0.001). Virtual non-contrast images from delayed dual-energy CT demonstrated strong agreement with true non-contrast images for CACS and AVCS, with 92.1% diagnostic concordance for severe aortic stenosis.
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