Comparison of Feasibility, Accuracy, and Reproducibility of Layer-Specific Global Longitudinal Strain Measurements Among Five Different Vendors: A Report from the EACVI-ASE Strain Standardization Task Force

Background: Despite standardization efforts, vendors still use information from different myocardial layers to calculate global longitudinal strain ( GLS). Little is known about potential advantages or disadvantages of using these different layers in clinical practice. The authors therefore investigated the reproducibility and accuracy of GLS measurements from different myocardial layers.Methods: Sixty-three subjects were prospectively enrolled, in whom the intervendor bias and test-retest variability of endocardial GLS ( E-GLS) and midwall GLS ( M-GLS) were calculated, using software packages from five vendors that allow layer-specific GLS calculation ( GE, Hitachi, Siemens, Toshiba, and TomTec). The impact of tracking quality and the interdependence of strain values from different layers were assessed by comparing test-retest errors between layers.Results: For both E-GLS and M-GLS, significant bias was found among vendors. Relative test-retest variability of E-GLS values differed significantly among vendors, whereas M-GLS showed no significant difference ( range, 5.4%-9.5% [ P =.032] and 7.0%-11.2% [ P =.200], respectively). Within-vendor test-retest variability was similar between E-GLS and M-GLS for all but one vendor. Absolute test-retest errors were highly correlated between E-GLS and M-GLS for all vendors.Conclusions: E-GLS and M-GLS measurements showed no relevant differences in robustness among vendors, although intervendor bias was higher for M-GLS compared with E-GLS. These data provide no technical argument in favor of a certain myocardial layer for global left ventricular functional assessment. Currently, the choice of which layer to use should therefore be based on the available clinical evidence in the literature. ( J Am Soc Echocardiogr 2018; 31: 374-80.)