Histogram Analysis of Native T1 Mapping and Its Relationship to Left Ventricular Late Gadolinium Enhancement, Hypertrophy, and Segmental Myocardial Mechanics in Patients With Hypertrophic Cardiomyopathy

Abstract

Background: The use of native T₁ mapping for evaluation of hypertrophic cardiomyopathy (HCM) is being explored, and its combination with histogram analysis may benefit the accuracy of such assessments.

Purpose: To investigate the relationship of segmental left ventricular wall thickness (LVWT), myocardial fibrosis, and strain parameters with segmental histogram parameters of native T₁ mapping in HCM patients.

Study type: Retrospective.

Subjects: Ninety-three HCM patients without previous cardiovascular diseases were included.

Field strength/sequence: 3.0T cardiac MR. Steady-state free precession cine imaging, modified Look-Locker inversion recovery, phase-sensitive inversion recovery.

Assessment: Images were assessed by three experienced radiologists.

Statistical tests: Mann-Whitney U-tests, area under the curve (AUC), Spearman's rank correlation, intraclass correlation coefficient, and Bland-Altman test were used for statistical analysis.

Results: A higher LVWT value correlated with higher means, minimums, 10^th /25^th /50^th /75^th /90^th percentiles, maximums, kurtosis, entropy, and lower SD and energy of T₁ mapping (P < 0.05 for all), with the correlation being stronger for entropy and energy (Spearman's rho = 0.439 and -0.413, respectively) than other parameters. Late gadolinium enhancement positive (LGE+) segments exhibited higher mean, minimum, 10^th /25^th /50^th /75^th /90^th percentiles, maximum, entropy, and lower energy of T₁ times than late gadolinium enhancement negative (LGE-) segments (P < 0.001 for all). Impaired strain function parameters (peak thickening and thickening rate in radial, circumferential, and longitudinal directions) demonstrated a weak correlation with higher entropy (P < 0.001 for all) and lower energy (P < 0.001 for all).

Data conclusion: Histogram parameters of native T₁ mapping provide more information than mean T₁ times alone. Among these parameters, entropy and energy may correlate better with LVWT, myocardial late gadolinium enhancement, and strain parameters than mean T₁ times in HCM patients.

Level of evidence: 2 Technical Efficacy Stage: 2 J. Magn. Reson. Imaging 2019;49:668-677.

Keywords: hypertrophic cardiomyopathy; magnetic resonance imaging; native T1 mapping; histogram analysis.