Vendor differences in 2D-speckle tracking global longitudinal strain: an update on a 10-year standardization effort

Aims To assess the inter-vendor differences in global longitudinal strain measurements and determine a potential improvement compared with the situation 10 years ago. Methods and results 372 echocardiographic exams were performed in 62 subjects (50 male, age 56 +/- 17) with LV ejection fraction ranging from 30% to 68%, using ultrasound systems from six manufacturers: GE, Philips, Canon, Siemens, Fujifilm and Esaote. Each subject was scanned consecutively on all machines by the same assigned sonographer, with two image sets per subject to assess test-retest setting reproducibility. Average peak systolic global strain from the three apical views (GLS(AV)) was measured on three vendor-specific (Canon, Siemens, and Fujifilm) and six vendor-agnostic (GE, Philips, US2.AI, Caas Qardia, Medis, and Epsilon) software solutions (SWS). Endocardial and mid-/full-wall GLS were measured and compared with the mean GLS of contemporary semi-automated clinical software: GE, Philips, Canon, Fujifilm, and Caas Qardia. Endocardial and mid-/full-wall GLS measurements from contemporary semi-automated clinical software showed minimal inter-vendor differences, with an average maximum bias of 0.6% strain units. There was a remaining inter-vendor bias with and among some other vendors. The average minimal detectable change with contemporary semi-automated clinical software was 2.5 and 2.4 strain% for endocardial and mid-/full-wall GLS, resp. These values were higher for and among some other vendors. Test-retest variability of GLS measurements was good and similar to that of LV ejection fraction (6.6% vs. 6.5%, P > 0.05), indicating consistent results across repeated scans. Conclusion In this controlled study setting, GLS measurements from companies that provide contemporary semi-automated clinical software have become more consistent, compared with 10 years ago. Mid-/full-wall strain was now available in all but one software.