CMR-Derived Extracellular Volume Radiomics in Reperfused STEMI: Long-Term Prognostic Value and Risk Stratification.

Aims: Global extracellular volume (ECV) fraction independently predicts outcomes after STEMI, but microvascular injuries complicate its interpretation. This study aims to assess the prognostic value of ECV-derived radiomics (RadScore) from cardiac magnetic resonance (CMR) for risk stratification in reperfused ST-elevation myocardial infarction (STEMI) patients.

Methods and results: We retrospectively included 441 reperfused STEMI patients (mean age 60±11 years; 371 males) from two centers, divided into development (n=347) and validation cohort (n=94) by centers. CMR scan was performed one week within the index event. ECV mapping was obtained from pre- and post-contrast T1 mappings. A radiomics score (RadScore) was developed through radiomics analysis on ECV mapping, and its predictive performance for major adverse cardiovascular events (MACE) was evaluated via logistic and Cox regression analyses. Over a median 3.1-year follow-up, MACE occurred in 81 patients (18.4%). RadScore showed strong predictive capability with an area under the curve (AUC) of 0.865 (95% confidence inerval [CI]: 0.768-0.962) and 0.821 (95%CI: 0.701-0.940) on the internal and external test cohort respectively, reclassifying 44% and 32% of patients over clinical model respectively. Patients with RadScore above the optimal threshold (RS+) experienced a more than 12-fold increase in MACE risk (95%CI: 2.96-47.71, P<0.001) after adjusting for known risk factors. RS+ provide incremental prognostic value beyond LVEF.

Conclusion: RadScore derived from ECV mapping was able to predict MACE and provided incremental prognostic value beyond established risk factors. Our findings underscore the potential long-term impact of acute changes in extracellular space patterns after myocardial infarction.