Diffusion tensor imaging can quantify cardiac fibrosis, with scarred tissue showing a greater than 80% increase in mean apparent diffusion coefficient and a greater than 40% decrease in fractional anisotropy compared to normal muscle.
Cardiac diffusion tensor imaging holds promise as a non-invasive, contrast-free tool to evaluate myocardial microstructure, fibrosis, and fiber orientation.
Abstract This review describes in brief recent magnetic resonance imaging (MRI) methods for assessing cardiac structure in healthy and pathologic state using diffusion-weighted (DW) and diffusion tensor imaging (DTI) approaches. A background on the theory and MR pulse sequences employed in DW/DT imaging is given, along with the calculation of diffusion tensor (D), apparent diffusion coefficient (ADC) and fractional anisotropy (FA). Parametric maps derived from DW/DT images can quantify microstructure alterations due to fibrotic collagen deposition, along with associated changes in cardiac muscle anisotropy. Representative examples of ADC and FA parametric maps are shown from ex vivo high-resolution DT images of explanted healthy and scarred hearts obtained from pre-clinical investigations. Furthermore, examples of fiber tractography demonstrating DTI-based 3D (three-dimensional) reconstruction of fiber directions within the heart are illustrated using advanced open-source software. Lastly, future developments and potential translation of DW/DT methods into routine clinical evaluation for cardiac MR imaging protocols are highlighted.
Pop et al. (Mon,) conducted a review in Myocardial infarction and cardiac fibrosis. Diffusion-Weighted (DW) and Diffusion Tensor (DT) MRI was evaluated. Diffusion tensor imaging can quantify cardiac fibrosis, with scarred tissue showing a greater than 80% increase in mean apparent diffusion coefficient and a greater than 40% decrease in fractional anisotropy compared to normal muscle.