Abstract 19302: Area Strain for the Assessment of Myocardial Infarction Scar Size by Ultrasound 3D Speckle Tracking: Validation with Late Gadolinium Enhancement Magnetic Resonance Imaging

Abstract

Background: Myocardial infarction scar size (ISS) is an important predictor of mortality, but accurate quantitative echocardiographic methods to determine ISS are lacking. We developed a new functional imaging method based on geometric analysis of 3D meshgrid-representations of the left ventricle (LV) derived from ultrasound 3D speckle tracking. The study was performed to validate our method for the quantitative assessment of ISS.

Methods: 3D full volume echocardiographic clips and late gadolinium enhancement magnetic resonance images (LGE-MRI) were acquired in 10 patients three months after acute myocardial infarction. ISS was determined from LGE-MRI images. 3D speckle tracking was performed on EchoPac (GE Vingmed), and LV meshgrids were analyzed offline using our novel software. Area strain, a parameter of regional wall thickening, was computed and displayed in 336 LV regions (figure). Infarction zone was delineated by a blinded observer as the region with reduced end-systolic area strain. The size of the delineated zone was calculated relative to the total LV surface.

Results: ISS in LGE-MRI ranged from 0 to 38% (median 18.5%). ISS closely correlated between echocardiography and LGE-MRI (figure). Bias and S.D. of bias of our method, as assessed from two different echocardiographic clips in all patient, was -1.94% and 5.01%, respectively.

Conclusions: The total size of reduced end-systolic area strain accurately reflects ISS as assessed by LGE-MRI. Thus, functional imaging based on 3D speckle tracking has great potential for the accurate determination of myocardial infarction scar size by echocardiography.