Abstract 702: Quantitative Cardiac Magnetic Resonance T1 Mapping Compared to Serologic Markers for Evaluation of Interstitial Fibrosis in Non-ischemic Cardiomyopathy
Background: Myocardial replacement fibrosis is a consequence of myocyte loss in patients with non-ischemic cardiomyopathy (NICM). While cardiac magnetic resonance (CMR) traditionally has been used to evaluate for macroscopic, visually-apparent scar, recently T1 mapping sequences have allowed identification of patients with interstitial fibrosis. We prospectively tested the utility of CMR in detecting left ventricular fibrosis in NICM compared to normal patient population in contrast to more traditional circulating markers of fibrosis.
Methods: We tested multiple serologic markers of collagen synthesis and degradation in 13 patients with NICM and 5 control patients. All subjects underwent CMR imaging. Post-gadolinium (Gd) whole-heart T1 relaxation was used as a non-invasive measure of myocardial fibrosis and was computed by the execution of a standardized inversion recovery-steady state free precession (IR-SSFP) sequence performed 5 minutes post-Gd. Three short-axis slices were imaged at multiple inversion times repeatedly in all patients. T1 relaxation times of the myocardium were computed by plotting the signal intensity over time. Left ventricular ejection fraction (EF) was calculated from short-axis cine images using commercially available software.
Results: Summarized in Table 1⇓.
Conclusions: CMR may allow detection of fibrosis in patients with NICM even in the absence of changes in relevant circulating markers of fibrosis compared to a control population. Further studies are warranted to determine if quantitative T1 mapping can reliably detect and quantify myocardial fibrosis that may assist with risk-stratification in this population.