Assessment of edema using STIR+ via 3D cardiovascular magnetic resonance imaging in patients with suspected myocarditis.

OBJECTIVE: To evaluate three-dimensional T2-weighted fast spin echo triple inversion recovery sequences (STIR+) for the diagnosis of myocardial edema in patients with suspected early myocarditis after respiratory or gastrointestinal tract viral infection and at follow-up.

MATERIALS AND METHODS: We prospectively examined 28 patients with suspected myocarditis and 37 controls matched for gender and age. An ECG-triggered STIR+ was used to cover the entire left ventricle in short-axis images with 10-mm slice thickness and no interslice gap. The global signal intensity ratio (heart muscle in relation to skeletal muscle) was calculated (global STIR+ ratio) to evaluate edema. All patients had repeat examinations at follow-up (mean interval 4.9 months, 1-12 months).

RESULTS: The mean global STIR+ ratio was 2.15 ± 0.4 in the initial examination of patients as compared to 1.78 ± 0.3 in controls (p < 0.0001) and 1.89 ± 0.3 in patients at follow-up (p = 0.0001 vs. first visit). Left ventricular ejection fraction did not differ between patients and controls at baseline and at follow-up.

CONCLUSION: We could identify a significantly higher global STIR+ ratio in patients with suspected myocarditis compared to controls, and a dynamic change during follow-up. The global STIR+ ratio may, therefore, be useful for the diagnosis of myocarditis and should be further explored.