Native T1 time and extracellular volume fraction in differentiation of normal myocardium from non-ischemic dilated and hypertrophic cardiomyopathy myocardium: A systematic review and meta-analysis.

BACKGROUND: Both native T1 time and extracellular volume (ECV) fraction have been shown to be important measures for the detection of myocardial fibrosis. However, ECV determination requires the administration of an intravenous contrast agent, whereas native T1 mapping can be performed without a contrast agent. METHODS: Here, we conducted a meta-analysis of myocardial native T1 data obtained for non-ischemic cardiomyopathy (NIC) patients and controls. A literature review included studies that applied T1 mapping using modified Look-Locker inversion recovery to measure myocardial fibrosis, and the results were validated by comparing datasets for dilated cardiomyopathy (DCM) or hypertrophic cardiomyopathy (HCM) patients and healthy controls (HCs). RESULTS: We identified 16 eligible studies. Pooled mean differences (MDs) and 95% confidence intervals (CIs) were estimated as follows. Native T1 at 1.5-T, DCM vs. HC: MD = 45.26 (95% CI: 30.92-59.59); HCM vs. HC: MD = 47.09 (95% CI: 32.42-61.76). Native T1 at 3.0-T, DCM vs. HC: MD = 82.52 (95% CI: 47.60-117.44); HCM vs. HC: MD = 115.87 (95% CI: 50.71-181.04). ECV at 1.5-T, DCM vs. HC: MD = 4.26 (95% CI: 3.06-5.46); HCM vs. HC: MD = 1.49 (95% CI: -1.45-4.43). ECV at 3.0-T, DCM vs. HC: MD = 8.40 (95% CI: 2.94-13.86); HCM vs. HC: MD = 8.02 (95% CI: 5.45-1-0.59). CONCLUSION: In conclusion, native T1 values were significantly different between NIC patients and controls. Native T1 mapping may be a useful noninvasive method to detect diffuse myocardial fibrosis in NIC patients.