The diagnosis of acute myocarditis is difficult because of the wide range of clinical symptoms. Noninvasive diagnosis relies on cardiac MRI, but its availability remains limited. CT spectral imaging has recently been proposed in this setting.

The aim of this study is to compare cardiac spectral CT scan to MRI for the diagnosis of myocarditis.

Between 2013 and 2015, 20 consecutive patients had an acute myocarditis according to cardiac MRI in our institution. All underwent a CT scan during the same time to compare with the MRI considered the gold standard. A coronary CT angiography was performed during the early enhancement and spectral analyses were performed 5 min after injection of iodine contrast agent, with late hyperenhancement defining inflammation. Using the 17 segments classification, we compared each myocardial segment using the 2 methods.

Mean age was 34±12 years with 90% of men. Symptoms were chest pain (100%) and palpitation (5%), and 75% of patients had a recent history of viral infection. Mean CRP was 64±65mg/l and troponin peak levels were 12±13ng/ml (normal <0.04). In Cardiac MRI, mean LVEF was 54±8%. The number of inflammatory myocardial segments was 3.1±3 in MRI and 3.6±2 in CT scan. When comparing each of the 17 segments using cardiac MRI or CT scan, no significant difference was found and the concordance Kappa coefficients was 0.83 p=0.001. The sensitivity in per patient and per segment analyses was respectively 100% and 81%. The effective dose to the patient during coroscanner and spectral scanner was respectively 4.6±1.8 and 1.2±0.2.

Spectral CT scan is valid compared to myocardial MRI for the diagnosis of acute myocarditis. Since CT scan is more easily available than MRI and can also rule out a coronary syndrome, it appears as an interesting option to diagnose myocarditis.

The author hereby declares no conflict of interest