T1 Mapping and Extracellular Volume in Cardiomyopathy Showing Left Ventricular Hypertrophy: Differentiation Between Hypertrophic Cardiomyopathy and Hypertensive Heart Disease.

Background: The aim of this study was to evaluate the capability of different magnetic resonance imaging (MRI) parameters for distinguishing between hypertrophic cardiomyopathy (HCM) and hypertensive heart disease (HHD). Methods: Thirty-eight patients with HCM, 35 patients with HHD, and 29 healthy controls subjects were enrolled in this study. All subjects underwent cardiac MRI to measure T1 values and extracellular volume (ECV), as well as the extent and patterns of late gadolinium enhancement (LGE). Myocardial segments were categorized as non-hypertrophic, mild-hypertrophic, moderate-hypertrophic, and severe-hypertrophic based on end-diastolic wall thickness (EDWT). The differences in native T1 values between all four groups were evaluated. Results: Native T1 values were significantly higher in patients with HCM than in patients with HHD and in healthy controls (both P < 0.001). Moreover, significantly increased ECV was shown in patients with HCM than in patients with HHD and in healthy controls (both P = 0.001). Native T1 values in the basal slice and apex slice were significantly higher in patients with HCM than in patients with HHD (P < 0.01). In patients with HCM, the non-hypertrophic myocardial segments demonstrated significantly elevated T1 values compared with patients with HHD (both P < 0.001). Using a cut-off value of 28.8% for ECV, it could differentiate between HCM and HHD with 85% sensitivity, 62.07% specificity, and an area under the curve of 0.772. Conclusion: In patients with HCM, T1 tissue remodeling occurs in the normal-appearing myocardial segments, but not in patients with HHD. Both native T1 values and ECV can support clinically relevant discrimination between HCM and HHD, although ECV had better diagnostic efficacy.