title: Velocity vector imaging in the measurement of left ventricular twist mechanics: head-to-head one way comparison between speckle tracking echocardiography and velocity vector imaging.
abstract: BACKGROUND
  Velocity vector imaging (VVI) is based on myocardial feature tracking, which incorporates speckle and endocardial border tracking and allows myocardial strains, strain rates, and velocities to be quantified. However, the accuracies of VVI-derived left ventricular rotation-associated values have not been validated, and the aim of this study was thus to perform a head-to-head comparison of twist-related values determined by VVI and speckle-tracking echocardiography (STE).
  
  
  METHODS
  Thirty-five patients with a wide spectrum of cardiac pathologies and 19 healthy subjects (a total of 54 subjects) were enrolled. Apical and basal short-axis images were obtained using GE Vivid 7 scanners at frame rates of 80 to 100 frames/s. Left ventricular rotation-related parameters were first obtained using EchoPAC version 7.0.1. For comparison purposes, the same basal and apical short-axis images were converted into uncompressed Digital Imaging and Communications in Medicine format and subsequently analyzed using Syngo version 3.0, which uses a VVI tracking algorithm.
  
  
  RESULTS
  Basal and apical peak rotation and peak twist determined using STE and VVI were well correlated (r = 0.80, P < .001, r = 0.87, P < .001, and r = 0.90, P < .001, respectively). With regard to rotation velocities, peak rotation and derotation velocities were moderately correlated at the basal (r = 0.70, P < .001, and r = 0.72, P < .001, respectively) and apical (r = 0.66, P < .001, and r = 0.51, P < .001, respectively) levels. Furthermore, twist and untwist velocities were moderately correlated between the two methods. However, the timings of peak rotation and derotation velocities and twist and untwist velocities were only weakly correlated at the basal and apical levels.
  
  
  CONCLUSIONS
  VVI is a feasible modality for assessing twist-related parameters. Although VVI agreed well with STE for most of the rotation-related parameters, poor concordance was found between the two methods for a few parameters. It is hypothesized that this discrepancy originates from the different tracking algorithms used. The findings indicate that caution should be exercised when interpreting or comparing twist-related parameters obtained using different echocardiographic devices with proprietary image analyzers.
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Dae-Hee
authors.initials: DH
authors.lastname: Kim
authors.forename: Hyung-Kwan
authors.initials: HK
authors.lastname: Kim
authors.forename: Min-Kyung
authors.initials: MK
authors.lastname: Kim
authors.forename: Sung-A
authors.initials: SA
authors.lastname: Chang
authors.forename: Yong-Jin
authors.initials: YJ
authors.lastname: Kim
authors.forename: Myung-A
authors.initials: MA
authors.lastname: Kim
authors.forename: Dae-Won
authors.initials: DW
authors.lastname: Sohn
authors.forename: Byung-Hee
authors.initials: BH
authors.lastname: Oh
authors.forename: Young-Bae
authors.initials: YB
authors.lastname: Park
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000465:Algorithms; D004452:Echocardiography / Q000379:methods*; D054459:Elasticity Imaging Techniques / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D006352:Heart Ventricles / Q000000981:diagnostic imaging*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012399:Rotation; D012680:Sensitivity and Specificity; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging*; D055815:Young Adult