The feasibility of low contrast dose dual-energy CT for quantifying myocardial focal scar via extracellular volume fraction

Abstract Objective To explore the quantitative efficacy of low-contrast-agent-dose dual-energy CT (DECT) myocardial extracellular volume (ECV) for myocardial focal scar (MFS). Methods 33 patients with confirmed old myocardial infarction (OMI) were prospectively enrolled. All underwent DECT late iodine enhancement (LIE), cardiac magnetic resonance (CMR) late gadolinium enhancement (LGE), native and enhanced T1 mapping. DECT-LIE-ECV and CMR-ECV were measured in 1-16 myocardial segments of the left ventricle. Additionally, with reference to the CMR-LGE images, DECT-LIE-ECV and CMR-ECV of the MFS and the remote myocardium at a same slice were measured. Quantitative performance was assessed via Spearman correlation, Bland-Altman analysis, ROC curves, and DeLong’s tests. Results A total of 438 myocardial segments from 28 patients were analyzed (including 101 MFS-positive, 337 MFS-negative). (2) MFS-positive segments showed higher ECV than MFS-negative (CMR: 41% vs 29%; DECT: 33% vs 25%). DECT-LIE-ECV correlated weakly with CMR-ECV (r = 0.21, P  Conclusion Low-contrast DECT-LIE-ECV accurately quantifies MFS when targeting scar regions directly, offering a promising supplementary tool for myocardial scar quantification, especially for patients with contraindications to CMR. Advances in knowledge The key finding of this study is the validation that low-contrast DECT-LIE-ECV enables accurate quantitative assessment of MFS via direct scar region targeting, providing a novel non-invasive supplementary to the reference standard CMR. This finding expands the clinical application of low-contrast DECT-LIE in cardiovascular imaging and supplements the evidence base for non-CMR-based ECV quantification in MFS assessment.