Prognostic Value of Multienergy CT–derived Myocardial Extracellular Volume Fraction in Noninfarcted Segments of Individuals with Chronic Coronary Syndrome

Purpose To evaluate the prognostic value of myocardial extracellular volume fraction (ECV) derived from multienergy CT with late iodine enhancement (LIE) in noninfarcted myocardial segments of individuals with chronic coronary syndrome (CCS). Materials and Methods This prospective study included consecutive participants with CCS who underwent LIE using multienergy CT following coronary CT angiography between March 2020 and December 2022. ECV was derived from only segments without LIE, and participants were dichotomized using a median-derived ECV cutoff value of 31%. Major adverse cardiovascular events (MACEs), including cardiac death, hospitalization for heart failure, myocardial reinfarction, and malignant arrhythmia, were recorded during follow-up. Kaplan-Meier and Cox regression analyses were performed to assess the association between noninfarcted ECV and MACEs. Results In total, 352 participants (median age, 68 years [IQR, 60-74 years]; 233 male) were included. During a median follow-up period of 41.7 months (IQR, 33.9-51.3 months), 76 participants experienced MACEs, including 17 cardiac deaths. Noninfarcted ECV was higher in participants with versus without LIE (median, 31.8% [IQR, 29.4%-35.1%] vs 30.6% [IQR, 28.5%-33.7%]; <i>P</i> = .01). Kaplan-Meier analysis showed that participants with high noninfarcted ECV had greater risk of MACEs and cardiac death (all log-rank <i>P</i> < .05). In multivariable Cox regression, high noninfarcted ECV remained independently associated with MACEs (hazard ratio, 1.11 [95% CI: 1.04, 1.18]; <i>P</i> < .001) after adjustment for covariates including LIE. Incorporating both LIE and ECV into a baseline model with clinical, anatomic, and functional information enhanced predictive performance for MACEs (final C-statistic, 0.80 [95% CI: 0.75, 0.85]; <i>P</i> < .001). Conclusion Noninfarcted ECV assessed using multienergy CT was independently predictive of MACEs and provided incremental prognostic value in individuals with CCS. <b>Keywords:</b> Applications-CT, Multienergy CT, Cardiac, Coronary Arteries © RSNA, 2026.