Automated cardiac strain estimation from short-axis DENSE and Cine MR images

Cardiac strains provide significant information to evaluate cardiac performance. They can be evaluated using full field voxel-wise displacements measured, for example, using displacement encoding with stimulated echoes (DENSE) magnetic resonance imaging (MRI) or from features and textures that are measured using Cine MRI. While DENSE MRI provides a more complete description of myocardial motion, it remains challenging to acquire and its adoption is not widespread. In contrast, Cine MRI is routinely acquired, and Cine-based cardiac strains could be more easily adopted in a clinical setting. To evaluate the feasibility of automatically estimating cardiac strains from Cine MRI, we compare slice-wise circumferential, longitudinal, and radial strains obtained with three mid-ventricular models: a two-slice DENSE model, a one-slice DENSE model, and a one-slice Cine model. Strains are computed after automatic image segmentation, and the models are evaluated using a computational deforming phantom and data acquired in forty ( $N=40$ ) healthy volunteers. When evaluated against the computational phantom, all models perform well in terms of circumferential strains, while differences are present in longitudinal and radial strains depending on model and location. When applied to volunteer data, the one-slice Cine model agrees reasonably well with the DENSE-based models in terms of endocardial circumferential strains while, overall, it leads to higher (in magnitude) radial and longitudinal strains, and lower (in magnitude) epicardial circumferential strains. The DENSE models lead to nearly identical estimates for circumferential and radial strains, while longitudinal strains are not correctly estimated by the one-slice DENSE model paired with automatic segmentation. The strain differences are discussed both group-wise and at the individual subject level.