Added value of native T1 mapping and extracellular volume fraction to late gadolinium enhancement in hypertrophic cardiomyopathy

Abstract

Background: Cardiac MRI allows for non-invasive and precise myocardial fibrosis evaluation within individuals having hypertrophic cardiomyopathy. Although myocardial native T1 mapping can quantify diffuse interstitial fibrosis, late gadolinium enhancement MRI can only identify focal fibrosis. Aim: The study objective was estimation of myocardial T1 mapping efficacy and calculated extracellular volume in differentiating segments with and without late gadolinium enhancement in individuals having hypertrophic cardiomyopathy.Patients and Methods: Our study involved 38 individuals diagnosed or suspected to be hypertrophic cardiomyopathy patients and a control group of ten individuals with no underlying health issues as a reference for native T1 values and extracellular volume. Cardiac MRI was performed for all subjects. Magnetic resonance scans comprised localizing white / black blood images, cine scans, native T1 mapping, late gadolinium enhancement and post contrast T1 mapping scans. Results: The native T1 was significantly longer in hypertrophic cardiomyopathy patients than in control subjects at all-time points (1049.048 ±50.930 ms) (938.106 ±36.368 ms) (p< 0.01) with a cutoff value of 1066 ms for myocardial fibrosis identification (a sensitivity of 74%, a specificity of 82%, and an accuracy of 85%). Also, extracellular volume was significantly greater within patients having hypertrophic cardiomyopathy (29.359±5.501ms) compared with controls (24.823±1.876 ms) (p< 0.02) with a threshold of 28% for fibrosis evaluation (a sensitivity of 53%, a specificity of 98%, and an accuracy of 78%).Conclusions: Native T1 values and extracellular volume show benefits while detecting and quantifying diffuse interstitial myocardial fibrosis not well visualized by late gadolinium enhancement MRI.