Analytic description of MR diffusion indices in ex-vivo human hypertrophic cardiomyopathy

Introduction: Hypertrophic cardiomyopathy (HCM) is the most common genetic heart disease and the leading cause of sudden death in the young [1]. HCM is well known to contain major changes at the structural level with myocytes disarray, increase in collagen content and modification of the extracellular matrix (ECM), that can only be determined using invasive focal myocardial biopsy or after death. In-vivo Diffusion Weighted Imaging (DWI) of the heart remains very challenging due to cardiac and respiratory motions. Most of the cardiac DWI studies have been performed with animals using a high-field scanner or extra-long time acquisition [2-3] but that will never be applicable to in-vivo imaging. Our objective is therefore to study hypertrophic cardiomyopathy in humans and to find MR diffusion indices that could reflect the myocardial fiber disarray and ECM changes. To set apart motion-related technical challenges but investigate the potential clinical value this technique could have in humans, we studied hypertrophic and control ex-vivo human hearts with spatial resolution that can be reproduced for in vivo cardiac studies. Imaging was performed within a few hours after sudden death and after forensic expertise.