Abstract 17917: Novel Techniques for the Diagnosis of Acute Myocarditis: A Clinical Cardiovascular Magnetic Resonance Study

Abstract

Background: CMR is well-established in the diagnosis of myocarditis, typically including dark-blood T2-weighted (T2W) imaging, early and late gadolinium imaging. Novel CMR techniques are now available, including bright-blood T2W-CMR, and T1-mapping which is also sensitive to changes in free water content. We hypothesized that these emerging methods can serve as new diagnostic criteria for myocarditis.

Methods & Results: We studied 34 patients with suspected acute myocarditis according to the Lake Louise Criteria and 45 controls. CMR (1.5T) within 12 days included (1) dark-blood T2 (STIR); (2) bright-blood T2 (ACUT2E); (3) T1-mapping (ShMOLLI); and (4) late gadolinium enhancement (LGE) (Fig 1). Image analysis was performed for (1) global myocardial T2 signal intensity (SI) ratio against skeletal muscle; (2) mean myocardial T1; (3) LGE. All patients had a CMR diagnosis of myocarditis, including positive T2-STIR and typical LGE pattern. Patient global myocardial T2 SI ratios by both dark-blood (1.81±0.28 vs 1.58±0.16, p<0.001) and bright-blood T2W-CMR (2.90±0.33 vs 1.82±0.19, p<0.001) were significantly higher than controls; mean myocardial T1 was also significantly higher (1027±62 ms vs 942±21 ms, p<0.001). Receiver operator characteristics analysis (Fig 2) showed good diagnostic performance for all methods: the area-under-the-curve for dark-blood T2, bright-blood T2 and T1-mapping were 0.79, 0.76 and 0.95, respectively.

Conclusions: Bright-blood T2W-CMR and T1-mapping detect acute myocarditis with good diagnostic accuracy. Non-contrast T1-mapping showed superior diagnostic performance compared to conventional dark-blood and newer bright-blood T2W-CMR.