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Despite standardization efforts, vendors still use specific proprietary software algorithms for echocardiographic strain measurements, which result in high inter-vendor variability. Using vendor-independent software could be one solution. Little is known, however, how vendor specific image characteristics can influence tracking results of such software. We therefore investigated the reproducibility, accuracy, and scar detection ability of strain measurements on images from different vendors by using a vendor-independent software. A vendor-independent software (TomTec Image Arena) was used to analyse datasets of 63 patients which were obtained on machines from four different ultrasound machine vendors (GE, Philips, Siemens, Toshiba). We measured the tracking feasibility, inter-vendor bias, the relative test-re-test variability and scar discrimination ability of strain measurements. Cardiac magnetic resonance delayed enhancement images were used as the reference standard of scar definition. Tracking feasibility on vendor datasets were significantly different (p < 0.001). Variability of global longitudinal strain (GLS) measurements was similar among the vendors whereas variability of segmental longitudinal strain (SLS) showed modest difference. Relative test-re-test variability of GLS and SLS showed no relevant differences. No significant difference in scar detection capability was observed. Average GLS and SLS values were similar among vendors. Reproducibility of GLS measurements showed no difference among vendors and was in acceptable range. SLS reproducibility was high but similar for all vendors. No relevant difference was found for identifying regional dysfunction. Tracking feasibility showed a substantial difference among images from different vendors. Our findings demonstrate that tracking results depend mainly on the software used and show little influence from vendor specific image characteristics.

Background: Segmental longitudinal strain (SLS)is reported to be vendor specific. Despite standardization efforts, vendors still use different myocardial layers for strain measurements. It is unclear, however, which layer is the most favorable for clinical purposes. Therefore, in this study we evaluated the reproducibility, accuracy, and scar detection ability of SLS measurements from different myocardial layers. Methods: In data sets of 58 patients with prior myocardial infarction and five healthy volunteers, we measured the intervendor bias, the relative test-retest variability, and scar discrimination ability of endocardial and midwall SLS, using software packages from four different companies (GE, Siemens, Toshiba, and TomTec). Cardiac magnetic resonance delayed enhancement images were used as the reference standard of scar definition. Results: Variability of SLS measurements was significant among the vendors for both midwall and endocardium. In addition, relative errors of SLS measurements varied considerably among vendors (P <.001 for both layers). Comparisons of test-retest errors from different layers for individual vendors did not show any significant differences. Regardless of the vendor, both endocardial and midwall strain values were decreased in scarred segments. Endocardial to midwall ratio of strain measurements showed no difference between scar-free and scarred segments. Endocardial and midwall strain parameters showed no significant difference in scar detection capability. Conclusions: Layer-specific SLS measurements vary significantly among vendors. Endocardial and midwall SLS measurements have a high yet comparable test-retest variability. Combining layer-specific SLS measurements does not provide additional information for detection of regional functional abnormalities. Our results do not provide evidence to favor the use of one myocardial layer over another.

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.)