Computed Tomography–Derived Extracellular Volume Fraction in Non–ST-Segment Elevation Myocardial Infarction With Multivessel Disease

Identifying the infarct-related artery (IRA) in non-ST-segment elevation myocardial infarction (NSTEMI) in patients with multivessel disease remains challenging. An 88-year-old man presented with chest pain. NSTEMI was diagnosed via electrocardiogram and elevated cardiac biomarkers. Coronary computed tomography angiography (CCTA) revealed intermediate-to-severe stenoses in the distal right coronary artery, proximal left anterior descending artery, diagonal branch, and mid-circumflex branch. CCTA-derived extracellular volume (ECV) fraction analysis demonstrated a regional elevation (31.3%) in the mid-anterolateral wall, corresponding to the diagonal branch territory. This elevated ECV fraction likely reflects acute myocardial inflammation and edema, aiding in IRA identification. Our findings suggest that computed tomography-based ECV mapping may localize acute ischemic injury, even in multivessel disease, by detecting focal edematous changes. Assessment of CCTA-derived ECV fraction could enhance IRA determination in NSTEMI, potentially guiding targeted revascularization strategies and reducing diagnostic uncertainty in complex cases.