The feasibility and diagnostic value of intravoxel incoherent motion diffusion-weighted imaging in the assessment of myocardial fibrosis in hypertrophic cardiomyopathy patients

Purpose: To investigate the feasibility and diagnostic value of intravoxel incoherent motion (IVIM) in the assessment of myocardial fibrosis in hypertrophic cardiomyopathy (HCM) patients. Methods: Fifty-five HCM patients underwent IVIM diffusion-weighted cardiovascular resonance imaging; Cine, T1 mapping, IVIM and late gadolinium enhancement (LGE) were performed. The relationship of strain, pre T1, extracellular volume (ECV), IVIM-derived parameters (D, D* and f) and LGE were analyzed based on 16 American Heart Association segments. Abnormal segments of myocardial fibrosis were defined as: the presence of LGE (LGE+) or ECV >= 29.6 %. Results: D parameter was significantly increased in LGE + vs LGE- (1.89 +/- 0.14 mu m(2)/ms vs. 1.63 +/- 0.12 mu m(2)/ms, p < 0.001) and ECV >= 29.6 % vs ECV < 29.6 % (1.84 +/- 0.13 mu m(2)/ms vs. 1.61 +/- 0.12 mu m(2)/ms, p < 0.001), respectively. D* and f parameters were significantly decreased in LGE + vs LGE- (D*: 34.9 +/- 6.6 mu m(2)/m vs 55.2 + 11.4 mu m(2)/m, p < 0.001; f: 10.8 +/- 1.29 % vs 12.5 +/- 1.26 %, p < 0.001) and ECV >= 29.6 % vs ECV < 29.6 % (D*: 37.5 +/- 6.9 mu m(2)/m vs 59.6 +/- 9.2 mu m(2)/m, p < 0.001; f: 10.9 +/- 1.1 % vs 13.00 +/- 1.0 %, p = 0.021), respectively. Moreover, significant correlations were demonstrated between D and ECV, as well as D* and f. Conclusions: : IVIM DW-CMR has proven to be ingenious in the investigation of myocardial fibrosis; D* and f parameters may have potential value to assess the perfusion status of fibrotic regions in HCM patients.