Abstract 16110: Segmental Comparison of Novel Feature Tracking MRI Strain and Echo Strain against Myocardial Scar Burden: Function May not Reflect Structure

Abstract

Background: Regional quantification of LV function in pts with ischemic heart disease is desirable but remains difficult. MRI feature tracking strain of cine-MRI DICOM images may be more feasible than MRI tagging. We sought to compare feature tracking MRI strain and echo strain in the detection of scar segments.

Methods: We analyzed two sets of 1072 segmental strains from 67 consecutive pts (63±10y, 55 men, EF 24±10%) who had cardiac MRI and echocardiography at an interval of 1±4 d. We excluded pts with LBBB, post-valvular surgery, or moderate or greater valvular heart disease. MRI strain by feature tracking was measured using two-dimensional (2D) cardiac performance analysis MR software (Tomtec, Germany) and 2D speckle echocardiographic strain with Velocity Vector Imaging (Siemens, Germany). Segmental longitudinal peak strain from apical 4-, 2- and 3-chamber views from Echo and MRI were compared with the amount of scar by MRI late Gadolinium enhancement.

Results: Both MRI strain and echo strain decreased as the scar increased (p<0.001 and p<0.001) (figure). These strain values were similar between the modalities, except for the non-scar region (p<0.001). This difference was derived from the basal (p<0.001) and apical levels (p<0.001), not from mid-level (p=0.888). Receiver operating characteristic analyses to discriminate non-scar region from transmural scar (>75%) showed modest area under the curves for both strains.

Conclusion: Feature tracking MRI strain and echo strain decrease similarly as the scar increases, except for non-scar area. However, neither of these strains has sufficient discriminative power to distinguish non-scar from transmural scar in ischemic cardiomyopathy. Function is not a good surrogate for structure.