title: Head-to-Head Comparison of Global Longitudinal Strain Measurements among Nine Different Vendors: The EACVI/ASE Inter-Vendor Comparison Study.
abstract: BACKGROUND
  This study was planned by the EACVI/ASE/Industry Task Force to Standardize Deformation Imaging to (1) test the variability of speckle-tracking global longitudinal strain (GLS) measurements among different vendors and (2) compare GLS measurement variability with conventional echocardiographic parameters.
  
  
  METHODS
  Sixty-two volunteers were studied using ultrasound systems from seven manufacturers. Each volunteer was examined by the same sonographer on all machines. Inter- and intraobserver variability was determined in a true test-retest setting. Conventional echocardiographic parameters were acquired for comparison. Using the software packages of the respective manufacturer and of two software-only vendors, endocardial GLS was measured because it was the only GLS parameter that could be provided by all manufactures. We compared GLSAV (the average from the three apical views) and GLS4CH (measured in the four-chamber view) measurements among vendors and with the conventional echocardiographic parameters.
  
  
  RESULTS
  Absolute values of GLSAV ranged from 18.0% to 21.5%, while GLS4CH ranged from 17.9% to 21.4%. The absolute difference between vendors for GLSAV was up to 3.7% strain units (P < .001). The interobserver relative mean errors were 5.4% to 8.6% for GLSAV and 6.2% to 11.0% for GLS4CH, while the intraobserver relative mean errors were 4.9% to 7.3% and 7.2% to 11.3%, respectively. These errors were lower than for left ventricular ejection fraction and most other conventional echocardiographic parameters.
  
  
  CONCLUSIONS
  Reproducibility of GLS measurements was good and in many cases superior to conventional echocardiographic measurements. The small but statistically significant variation among vendors should be considered in performing serial studies and reflects a reference point for ongoing standardization efforts.
authors.affiliation: University Hospital Gasthuisberg, Catholic University Leuven, Leuven, Belgium.
authors.forename: Konstantinos E
authors.initials: KE
authors.lastname: Farsalinos
authors.affiliation: University Hospital Gasthuisberg, Catholic University Leuven, Leuven, Belgium.
authors.forename: Ana M
authors.initials: AM
authors.lastname: Daraban
authors.affiliation: University Hospital Gasthuisberg, Catholic University Leuven, Leuven, Belgium.
authors.forename: Serkan
authors.initials: S
authors.lastname: Ünlü
authors.affiliation: Bluhm Cardiovascular Institute, Northwestern University, Chicago, Illinois.
authors.forename: James D
authors.initials: JD
authors.lastname: Thomas
authors.affiliation: Department of Cardiac, Thoracic and Vascular Sciences, University of Padua, Padua, Italy.
authors.forename: Luigi P
authors.initials: LP
authors.lastname: Badano
authors.affiliation: University Hospital Gasthuisberg, Catholic University Leuven, Leuven, Belgium. Electronic address: jens-uwe.voigt@uzleuven.be.
authors.forename: Jens-Uwe
authors.initials: JU
authors.lastname: Voigt
mesh_terms: D000328:Adult; D026683:Advisory Committees; D000704:Analysis of Variance; D004452:Echocardiography / Q000295:instrumentation* / Q000592:standards*; D004867:Equipment Design; D004869:Equipment Safety; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007221:Industry / Q000706:statistics & numerical data*; D038622:Internationality; D008297:Male; D015588:Observer Variation; D015203:Reproducibility of Results; D012984:Software; D016276:Ventricular Function / Q000502:physiology*
keywords: Deformation; Left ventricle; Speckle-tracking echocardiography; Strain; Systolic function