Myocardial Late Enhancement in Contrast-Enhanced Cardiac MRI: Distinction Between Infarction Scar and Non–Infarction-Related Disease

OBJECTIVE: Our objective was to assess and compare the patterns of late enhancement (LE) in contrast-enhanced cardiac MRI caused by myocardial infarction and different myocardial diseases that are not related to ischemic infarction. MATERIALS AND METHODS: A total of 811 consecutive contrast-enhanced cardiac MRI studies performed for different indications were reviewed for left ventricular myocardial LE after gadopentetate dimeglumine administration. MRI studies were performed on a 1.5-T scanner using an inversion recovery turbo FLASH sequence (TR/TE, 8/4 msec; flip angle, 25 degrees). The LE pattern of ischemic infarction scar was compared with that in nonischemic myocardial disease. RESULTS: LE was found in 421 (52%) patients. In all patients with myocardial infarction, LE included the subendocardial layer. Nineteen patients without history of myocardial infarction and angiographically excluded coronary artery disease showed different patterns of LE caused by myocarditis, sarcoidosis, arrhythmogenic right ventricular dysplasia, cardiomyopathy, endomyocardial fibrosis, and iatrogenic scars after biopsy, ablation of septal hypertrophy, and myocardial laser revascularization. CONCLUSION: LE in contrast-enhanced cardiac MRI is not specific for ischemic infarction. LE in ischemic infarction always involves the subendocardial layer, whereas it does not necessarily do so in other myocardial diseases. Therefore, if LE omit the subendocardial layer, different nonischemic myocardial diseases have to be considered. The pattern of LE might be helpful for the differential diagnosis of myocardial disease and in distinguishing it from ischemic disease.