[Contribution of 64-slice cardiac tomodensitometry for non-invasive diagnosis of acute myocarditis]

The association of acute chest pain, elevation of the cardiac enzymes and biological markers of inflammation suggests the diagnosis of myocarditis. The aim of the present study is to evaluate the diagnostic value of the multidetectors cardiac tomodensitometry (MDCT) for the confirmation of this diagnosis.

From October 2005 to April 2011, 39 patients aged 15.4 to 75.7years (mean 43.3±15.1) underwent a MDCT for suspected acute myocarditis (chest pain, elevation of troponin I, systemic inflammation). The electrocardiogram highlighted repolarization disorders in 27 (69%) patients (negative T waves, elevation of ST segment). The MDCT consisted in a first acquisition phase (imaging of coronary arteries) followed 7minutes later by a late acquisition, with thicker slices (imaging of the myocardium). When the MDCT was performed after a coronary angiography, only the late acquisition was performed. Sixteen patients then underwent a cardiac MRI.

No significant coronary stenoses were found in all patients. The MDCT showed homogeneous myocardial enhancement on the early acquisition. A subepicardial late enhancement was found in 30 (76.9%) patients. The subepicardial enhancement was mainly found in the lateral myocardium. In patients who underwent cardiac MRI and MDCT (n=16), there was a good correlation between the enhanced segments. MDCT found differential diagnosis in 11 patients (myocardial infarction, Tako-Tsubo).

The ECG-gated MDCT is a non-invasive and reliable diagnostic tool in patient with suspected myocarditis. It allows at the same time to rule out a significant coronary disease, when no coronary angiography was performed, and to show subepicardial enhancement confirming the diagnosis of myocarditis. While cardiac MRI remains the gold standard, MDCT could prove useful when there is no access to or contraindication for an MRI, studying both the coronary arteries and the myocardium.