title: Velocity vector imaging in the measurement of left ventricular myocardial mechanics on cardiac magnetic resonance imaging: correlations with echocardiographically derived strain values.
abstract: BACKGROUND
  Regional and global function can be measured by echocardiography using speckle-tracking, a technique that has previously been validated against crystal sonomicrometry. However, the application of Velocity Vector Imaging (VVI) to images obtained from cardiac magnetic resonance (CMR) imaging has never been validated against those values derived from VVI applied to two-dimensional echocardiographic images in the same patient group. The aim of this study was to validate for the first time the application of VVI to retrospectively acquired CMR data sets for the assessment of left ventricular strain and rotation, using echocardiographic strain assessment by VVI as the reference technique.
  
  
  METHODS
  Cine steady-state free precession CMR data sets and two-dimensional echocardiographic images obtained on the same day in 36 adult patients with hypertrophic cardiomyopathy were analyzed retrospectively using VVI to quantify global longitudinal and circumferential strain and rotation parameters.
  
  
  RESULTS
  The absolute differences in longitudinal strain between the two imaging modalities were -1.1 ± 3.3% (endocardial) and -2.2 ± 3.6% (full thickness). The absolute differences in circumferential strain were -4.7 ± 5.3% (endocardial) and -3.4 ± 3.8% (full thickness). CMR consistently resulted in higher strain values than echocardiography. The absolute differences in twist were -0.2 ± 5.6% (endocardial) and 0.1 ± 5.8% (full thickness).
  
  
  CONCLUSIONS
  The application of VVI to CMR data sets allows a feasible and reproducible method for strain analysis in HCM, demonstrating excellent agreement with two-dimensional echocardiography-derived values. Given the superior image quality obtained with CMR in a significant proportion of patients, this technique provides a method for strain assessment without the need for dedicated CMR acquisition and analytic techniques.
authors.affiliation: Division of Cardiology, Peter Munk Cardiac Centre, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada. Electronic address: lynne.williams2@uhn.ca.
authors.forename: Lynne K
authors.initials: LK
authors.lastname: Williams
authors.affiliation: Hypertrophic Cardiomyopathy Center, Division of Cardiology, Tufts Medical Center, Boston, Massachusetts.
authors.forename: Jose A
authors.initials: JA
authors.lastname: Urbano-Moral
authors.affiliation: Hypertrophic Cardiomyopathy Center, Division of Cardiology, Tufts Medical Center, Boston, Massachusetts.
authors.forename: Ethan J
authors.initials: EJ
authors.lastname: Rowin
authors.affiliation: Division of Cardiology, Peter Munk Cardiac Centre, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada.
authors.forename: Michal
authors.initials: M
authors.lastname: Jamorski
authors.affiliation: Division of Cardiology, Peter Munk Cardiac Centre, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada.
authors.forename: Beata
authors.initials: B
authors.lastname: Bruchal-Garbicz
authors.affiliation: Department of Cardiology, Rambam Health Care Campus, Haifa, Israel.
authors.forename: Shemy
authors.initials: S
authors.lastname: Carasso
authors.affiliation: Tufts University School of Medicine, Tufts Medical Center, Boston, Massachusetts.
authors.forename: Natesa G
authors.initials: NG
authors.lastname: Pandian
authors.affiliation: Hypertrophic Cardiomyopathy Center, Division of Cardiology, Tufts Medical Center, Boston, Massachusetts.
authors.forename: Martin S
authors.initials: MS
authors.lastname: Maron
authors.affiliation: Division of Cardiology, Peter Munk Cardiac Centre, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada.
authors.forename: Harry
authors.initials: H
authors.lastname: Rakowski
mesh_terms: D000328:Adult; D002312:Cardiomyopathy, Hypertrophic / Q000000981:diagnostic imaging*; D004452:Echocardiography / Q000379:methods*; D054459:Elasticity Imaging Techniques / Q000379:methods*; D005260:Female; D006352:Heart Ventricles / Q000000981:diagnostic imaging*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D016277:Ventricular Function, Left
keywords: 2D; CMR; Cardiac magnetic resonance; Echocardiography; HCM; Hypertrophic cardiomyopathy; Myocardial mechanics; SSFP; Steady-state free precession; Two-dimensional; VVI; Velocity Vector Imaging