Statistical significance of 3D motion and deformation indexes for the analysis of LAD infarction
Résumé
Purpose: Deformation analysis from 3D echocardiography results in a considerable amount of parameters, for which the conventional statistical approach is cumbersome. We investigate local motion and deformation patterns to determine the parameters of relevance for the study of LV myocardial deformation in the presence of LAD infarct.
Methods: The study included 46 patients acquired at max. 5 days after LAD infarct (37 sequences) and at 1-year follow-up (33 sequences), and 46 controls. Patients were selected if they had a LVEF<50% or 3 akinetic segments in the LAD territory. 3D speckle-tracking of the LV (QLab prototype) was performed, and included endo/epicardial segmentations at end-diastole/end-systole, and manual corrections on the output. The tracked meshes were post-processed to extract local radial/circumferential/longitudinal deformation and motion, and spatiotemporally aligned to a common reference to allow for intra- and inter-subject statistical comparisons.
Results: Regions with significant decrease in longitudinal strain coincide with the theoretical LAD infarct localization (fig). Lateral segments improved longitudinal strain at follow-up (AHA#1: p=0.004 [baseline] vs. p=NS [follow-up]; AHA#11&12: p<0.001 [baseline] vs. p=NS [follow-up]). Abnormalities in circumferential and radial displacement partially overlapped the infarct region, while longitudinal displacement and circumferential/radial strain did not provide relevant information.
Conclusion: Our generic statistical comparison framework is useful to identify a subset of motion and deformation parameters that is relevant to characterize myocardial viability, which is also coherent with physiological improvements at follow-up.