Myocardial fibrosis evaluated by diffusion-weighted imaging and its relationship to 3D contractile function in patients with hypertrophic cardiomyopathy.

Background: Previous studies have shown that diffusion-weighted imaging (DWI) is sensitive to myocardial fibrosis in ischemic and nonischemic cardiomyopathy.

Purpose: To explore the prognostic value of apparent diffusion coefficient (ADC) for detecting myocardial fibrosis and its relationship to the contractile function in hypertrophic cardiomyopathy (HCM).

Study Type: Prospective.

Population: A total of 45 HCM patients and 20 controls.

Field Strength/sequence: 3.0T cardiac MRI. The cardiac MR sequences included cine, T mapping, and DWI.

Assessment: According to the presence of late gadolinium enhancement (LGE) and the extracellular volume (ECV) values (+2 SD of control subjects), respectively, reader W and reader J assessed the value of ADC of each segment for detecting myocardial fibrosis and its relationship to impaired contractile function in HCM patients.

Statistical Tests: Independent sample t-test, Pearson analysis, and intraclass correlation (ICC).

Results: The value of ECV was 23.6 ± 3.0% for control. ECV ≥ 29.6% and ECV < 29.6% groups were classified. ADC values in the ECV ≥ 29.6% group were significantly increased compared to the ECV < 29.6% group, (2.41 ± 0.23 μm /ms vs. 2.03 ± 0.16 μm /ms, P < 0.005). Compared to the LGE - group, ECV (32.1 ± 2.3% vs. 29.0 ± 2.8%, P < 0.005) and ADC (2.60 ± 0.18 μm /ms vs. 2.10 ± 0.07 μm /ms, P < 0.005) values were significantly increased in the LGE + group. ADC values were linearly associated with ECV values (R  = 0.65) in HCM patients. ADC values were linearly associated with circumferential and longitudinal strain (R  = 0.60, R  = 0.46), as well as circumferential, longitudinal, and radial strain rate (R  = 0.13, R  = 0.25, R  = 0.17, respectively).

Data Conclusion: Contractile dysfunction in HCM is predominantly associated with ADC, which is a feasible alternative to ECV and LGE for detecting myocardial fibrosis.

Level Of Evidence: 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;48:1139-1146.