cute chest pain or anginal equivalents associated with mild troponin rise remain a diagnostic challenge, particularly in patients at low to intermediate risk for acute coronary syndrome. Coronary CT angiography can be used to safely triage these patients (1,2). In previous large multicenter trials with participants with acute chest pain at low to intermediate pretest risk of acute coronary syndrome, coronary CT angiography was associated with higher detection of coronary artery disease (CAD) (3), shorter length of stay (3,4), and higher rate of discharge (3,4) compared with the standard of care, without an increase in major adverse events at 28 days (4) and at a longer follow-up (5). Acute aortic syndrome, pulmonary embolism, and CAD can be simultaneously ruled out with use of a triple-rule-out (TRO) CT protocol (6,7). However, a TRO CT study cannot help identify nonvascular causes of acute myocardial injury (8). In patients with troponin-positive acute chest pain and unobstructed coronary arteries, cardiac MRI was found to provide a diagnosis in 74%-95% (9-12), identifying myocarditis, takotsubo cardiomyopathy, and myocardial infarction with nonobstructed coronary arteries as the most frequent causes of symptoms and alteration in cardiac biologic markers (10-12). Cardiac MRI was found to change the Background: Acute chest pain with mild troponin rise and inconclusive diagnosis after clinical evaluation represents a diagnostic challenge. Triple-rule-out (TRO) CT may exclude coronary artery disease (CAD), as well as acute aortic syndrome and pulmonary embolism, but cannot help identify other causes of myocardial injury.Purpose: To investigate the diagnostic value of a comprehensive CT protocol including both an angiographic and a late contrast enhancement (LCE) scan in participants with troponin-positive acute chest pain.
Materials and Methods:In this prospective study, consecutive patients with troponin-positive acute chest pain or anginal equivalent and inconclusive diagnosis after clinical evaluation (symptoms, markers, electrocardiography, and echocardiography) who underwent TRO CT between June 2018 and September 2020 were enrolled. TRO CT was performed to evaluate the presence of obstructive CAD (stenosis 50%), acute aortic syndrome, and pulmonary embolism. If the findings on the TRO CT scan were negative, an LCE CT scan was acquired after 10 minutes to assess the presence and pattern of scar and quantify the myocardial extracellular volume fraction. CT-based diagnoses were compared with diagnoses obtained with reference standard methods, including invasive coronary angiography, cardiac MRI, and endomyocardial biopsy.Results: Eighty-four patients (median age, 69 years [interquartile range, 50-77 years]; 45 men) were enrolled. TRO CT helped identify obstructive CAD in 35 participants (42%), acute aortic syndrome in one (1.2%), and pulmonary embolism in six (7.1%). LCE CT scans were acquired in the remaining 42 participants. The following diagnoses were reached with use of LCE CT: myocarditis (22 of 42 partici...