A real-life clinical application of cardiac magnetic resonance imaging in patients with acute myocarditis - one-center observational retrospective study.

Background: The diagnosis of acute myocarditis is complex, with cardiac magnetic resonance (CMR) being a recommended diagnostic method. This study aimed to evaluate the real-life use of CMR in the diagnosis of acute myocarditis and to correlate CMR results with the degree of myocardial damage.

Methods: This is a retrospective, observational tertiary single-center study of 90 consecutive patients (F/M:18/72, mean age:39 ± 14 years) hospitalized between 2015-2022 with a clinical diagnosis of acute myocarditis. The study population was divided into two groups: patients who underwent CMR+ and those who did not undergo CMR - In the CMR+ group, various sequences, including T1/T2-weighted imaging, late gadolinium enhancement (LGE), and mapping techniques, were used to assess myocardial inflammation and damage.

Results: CMR was performed in 39 patients (43.3%, F/M:10/29, mean age:41 ± 16 years). In this group, myocardial edema (increased T2 signal intensity) was detected in 29 patients, and LGE (signal intensity 2 standard deviations cabove normal on T1 images) was found in 39 patients. Diagnosis based on Lake Louise Criteria was possible in 29 cases. Edema negatively correlated with TnT levels (r = -0.412, p < 0.05) and positively with the number of LGE segments (r = 0.372, p < 0.05). Significant correlations were found between LVEF and LGE mass (r = -0.360, p < 0.05), and maximal TnT levels (r = -0.38, p < 0.05). CMR+ patients had lower myocardial damage markers and CRP concentrations compared to CMR- patients.

Conclusions: CMR is underused in diagnosing acute myocarditis. Myocardial damage markers correlate with CMR-detected edema and volumetric measures, but not LGE extent. More research is needed to enhance risk assessment and treatment.