Cardiac Magnetic Resonance Visualization of the Myocardial Microstructure in Non-Ischemic Cardiomyopathies

Abstract

Cardiac magnetic resonance (CMR), a non-radiation based type of examination, can achieve the simultaneous comprehensive multi-parameter, multi-plane, and multi-sequence evaluation of the anatomical structure of the heart; and at the same time, determine systolic and diastolic function, and blood perfusion and tissue characteristics. Traditional late gadolinium enhancement imaging based on CMR reflects focal replacement fibrosis, in contrast to normal myocardial signal intensity, but cannot effectively identify diffuse myocardial fibrosis. T1 mapping and its derived extracellular volume fraction can be used to quantitatively analyze the extracellular space in myocardial tissue and evaluate diffuse myocardial interstitial fibrosis that is invisible to the naked eye. Diffusion tensor imaging reveals the direction of cardiomyocyte aggregates by quantifying the anisotropy of water molecule diffusion, and can be applied to evaluate the integrity of myocardial tissue and arrangement structure of myocardial microstructural characteristics. On the basis of the micro-motion of myocardial tissue, feature tracking analysis decomposes myocardial deformation into three dimensions of micro-mechanical changes, and can identify early systolic and diastolic dysfunction before heart enlargement or ejection fraction reduction. This Commentary discusses current research advances in these new techniques, as well as their clinical application prospects and limitations for non-ischemic cardiomyopathies.