The role of cardiac CT with late iodine enhancement in patients with acute cardiac symptoms and troponin elevation in the era of high-sensitivity assays.

objectivesDiagnostic workup of patients with acute cardiac symptoms, troponin elevation, and no acute myocardial infarction (AMI) criteria is challenging. Cardiac CT angiography (CCTA) rules out obstructive coronary artery disease (CAD). Adding late iodine enhancement and extracellular volume fraction (CCTA + LIE/ECV) provides insights into myocardial injury. However, the impact on working diagnosis, agreement with discharge diagnosis, and mid-term safety of implementing CCTA + LIE/ECV in the emergency department remains uncertain. MATERIALS AND

methodsProspective study on consecutive patients presenting, from June 2018 to February 2025, with acute chest pain or equivalents, elevated troponin, and no AMI diagnosis, excluding previously revascularized patients. Patients underwent CCTA to rule out obstructive CAD (≥ 50% stenosis). CCTA-negative patients underwent myocardial tissue characterization with LIE; if negative, ECV was quantified. PRIMARY ENDPOINT: modification of working diagnosis by CT. Secondary endpoints: agreement between CT and discharge diagnoses after standard-of-care assessment; mid-term major adverse cardiovascular events (MACEs) in CT-negative patients.

resultsAmong 191 patients (age 70 [55-79] years; 53% men), CCTA identified obstructive CAD in 76/191 (40%). LIE/ECV were positive in 58/106 (55%) of CCTA-negative cases, revealing myocarditis in 32/106 (30%), AMI with non-obstructive CAD in 8/106 (8%), Takotsubo in 14/106 (13%), amyloidosis in 3/106 (3%), and dilated cardiomyopathy in 1/106 (1%). CT modified the working diagnosis in 91/191 (48%) patients. Agreement between CT and discharge diagnosis was 0.94 (95% CI 0.89-0.97). In patients with negative CCTA + LIE/ECV, no MACEs occurred after 24 [interquartile range, 19-29] months.

conclusionIn patients with acute symptoms, elevated troponin, and no AMI, a protocol combining CCTA + LIE/ECV enables etiologic assessment of coronary and myocardial conditions, refines working diagnosis, and entails a favorable prognosis when negative. KEY POINTS: Question Patients with acute cardiac symptoms, troponin elevation, and no evidence of acute myocardial infarction represent a diagnostic challenge: cardiac CT with late iodine enhancement may have diagnostic and prognostic implications. Findings CT angiography with late iodine enhancement provided a diagnosis in 75% of patients and modified the working diagnosis in 48%. In the 25% CT-negative patients, no adverse events occurred at mid-term follow-up. Clinical relevance A CT protocol including coronary artery evaluation and myocardial tissue characterization may provide a rapid etiological diagnosis in patients with acute symptoms and troponin elevation, potentially supporting earlier clinical decision-making and reducing the need for additional downstream testing.