Abstract 14046: Cardiac Magnetic Resonance Imaging in Active and Borderline Biopsy-proven Myocarditis: Results From a Prospective Series
Cardiac magnetic resonance (CMR) with T2-weighted STIR (T2W) and T1-weighted late gadolinium enhancement (LGE) sequences is widely used in the non-invasive diagnosis of myocarditis, but its role in differentiating biopsy-proven active versus borderline myocarditis, based on the histological Dallas Criteria, is not well defined.
Purpose: We used T2-weighted STIR (T2W) and T1-weighted late gadolinium enhancement (LGE) CMR imaging (1.5 T) in 65 consecutive patients with biopsy-proven myocarditis (BPM) to assess CMR accuracy in differentiating active vs. borderline myocarditis.
Methods: We studied 65 patients with BPM, 35 of whom with active myocarditis, defined as inflammation with evidence of non-ischemic myocyte necrosis, and 30 with borderline myocarditis, characterized by the presence of myocardial inflammation without myocyte necrosis, in keeping with the Dallas Criteria. CMR was performed, according to the Lake Louis Criteria, using T2W imaging for myocardial edema and T1-weighted sequence for LGE detection.
Results: Myocardial edema was present in 20 patients with active myocarditis and in 11 with borderline myocarditis. LGE was found in 25 patients with active versus 20 with borderline myocarditis. Detection of LGE alone was quite sensitive (71.4%) but had a very low specificity (33.3%) in the diagnosis of active myocarditis, whereas presence of edema was less sensitive than LGE (64%) but more specific (62%). Detection of both myocardial edema and LGE in the same patient was highly sensitive (78.9%) but had low specificity (50%) for the diagnosis of histologically proven active myocarditis.
Conclusions: CMR is a well-established method for the non-invasive diagnosis of myocarditis but its accuracy in differentiating between acute and borderline myocarditis, defined on the basis of histological criteria, is not satisfactory, because of a high number of false positives. It remains to be seen whether the application of T1-weighted sequences for detection of early enhancement, in addition to T2W and LGE, will increase diagnostic CMR accuracy in the diagnosis of active biopsy-proven myocarditis.
- © 2013 by American Heart Association, Inc.