Background and Objective: Despite numerous research studying the accuracy of various diagnostic methods used for the diagnosis of acute myocarditis, an ultimate method is yet to be found. Due to advances in terms of imaging and the development of modalities with high specificity and sensitivity, cardiac MRI (CMR), Transthoracic echocardiograms (TTE) and computerized tomography (CT) compete to help in the challenging diagnosis of diseases such as myocarditis that have diverse clinical presentations. This study compares the findings of CMR and TTE and their role in confirming the diagnosis of myocarditis in clinically diagnosed patients. Materials and Methods: This cross-sectional study was done in the imaging department of Shaheed-Rajaaee hospital in the years 2016 and 2017. Using a census procedure all patients with suspected myocarditis. (symptoms included chest pain, change in ECG and troponin levels) Acute coronary syndrome (ACS) was ruled out. After the completion of stabilizing procedures and acute coronary the patients underwent further assessment using CMR and TTE in order to study the diagnostic capabilities of CMR with more certainty. (n=100) The appearance of hyperenhancement in the myocardium in the post GD T1 phase, myocardial edema in STIR sequences and severe decrease of LVEF in cine images were considered as a confirmation of the myocarditis diagnosis. Moreover, the echocardiograms were obtained (using TTE), wall motion abnormality and pericardial effusion were also assessed in these patients. The results were compared using statistical analysis. Findings: 38 male patients and 62 female patients with the mean age of 37.16 ± 17.39 participated in the study. The estimated ejection fraction of the transthoracic echocardiograms was 36.15 ± 15.29 (domain 10-65) and 38.64 ± 14.10 for the cardiac MRI (domain 9-63) respectively. In 12% of the patients pericardial effusion was observed in the TTE. And 25% in the CMR regarding pericardial effusion. In 59% of the patients TTE showed wall motion abnormality and the majority of the involvement(13.5%) was global. In 36 % of the patients CMR revealed wall motion abnormality 13.8 % of which was regional and 86.1% global. STIR sequences were obtained to observe tissue edema and led to positive results in 71% of the patients. Myocard T2/Muscle T2 ratio was more than 1.9 in 29% of the patients and less than 1.9 in the remaining 32%. In the CMR investigations, 10% of the patients showed epicardial enhancement. moreover , delayed enhancement was observed in 66% of patients suspected of myocarditis. Discussion and Conclusion: The results of this investigation showed the imaging findings of CMR have more significant capabilities in detecting/confirming myocarditis compared to TTE.
