1354752 - Correlation Between CMR-Feature Tracking Derived Regional Myocardial Strain at Peak Stress and Segments with Ischemia and Prior Infarcts

Ventricular contractile function serves as a critical marker of cardiac disease with significant impact on morbidity and mortality. Wall motion abnormality (WMA) and perfusion defects play a central role in ischemic evaluation. Cardiac magnetic resonance feature tracking (CMR-FT) is an effective modality in evaluating myocardial deformation. CMT-FT quantifies myocardial deformation utilizing an already acquired cine images. Our objective is to assess the difference of regional strain at peak stress between healthy myocardial segments and those with either WMA or perfusion defects.



Methods:

A retrospective chart review conducted on patients who underwent a regadenoson stress CMR between 2017-2018. 36 studies were identified in the analysis and based on the American Heart Association standard model; the left ventricle was divided into 16 segments excluding the apical cap. CMR-FT derived regional myocardial strain was calculated utilizing CVI42® software. A total of 559 segments were included in the perfusion analysis (520 without and 39 with perfusion defects). Perfusion defects were defined as an infarct (fixed defect) vs ischemia (reversible defect). A total of 565 segments were included in the WMA analysis (485 without and 80 with WMA).



Results:

A significant difference was identified in peak radial strain for segments with WMA, 22.6±1.6% vs without 45.6±0.9% (p< 0.001). Peak circumferential strain for segments with WMA was also reduced at -13.4±0.9% vs without -21.9±0.3% (p< 0.001). Variability was delineated when analyzing the separate segments of myocardium (base, mid, and apical), however, the degree of difference between the radial and circumferential strain for each segment of myocardium with and without WMA remained significant (for all p< 0.001).

 
Regarding perfusion defect, a significant difference was identified in overall peak radial strain with and without perfusion defects (30.6±3.6% vs 43.2±0.9%; p< 0.001). Overall peak circumferential strain decreased in segments with perfusion defects compared to without (-16±1.7% vs -21±0.3%; p< 0.001). In further analyzing healthy myocardium to myocardium with ischemic or infarcted segments, a progressive reduction in both radial and circumferential strain was demonstrated. Segment radial strain in healthy myocardium was 43.18±0.93% vs ischemic 33.19±3.6% vs infarcted 7.45±9.9% segments. Segment circumferential strain in healthy myocardium was -21.03±0.3% vs ischemic -16.45±1.82% vs infarcted -11.97±2.37% segments.

 



Conclusion:

Significant regional myocardial strain differences are demonstrated in segments with healthy myocardium in comparison to those segments with WMA. A notable reduction in strain was identified in myocardium with infarcted segments versus ischemic segments both of which were greatly reduced in comparison to healthy myocardium. This analysis may aid clinicians in providing a more objective quantification of difficult to assess segments.