title: Feasibility and accuracy of different techniques of two-dimensional speckle based strain and validation with harmonic phase magnetic resonance imaging.
abstract: BACKGROUND
  Different 2-dimensional speckle-based strain techniques have been developed to overcome the problem of angle dependency with Doppler-based strain. However, their relative accuracy has not been assessed. The aim of this study was to determine the feasibility and accuracy of 2 such techniques (velocity vector imaging [VVI] and automated function imaging [AFI]), using tagged harmonic phase (HARP) magnetic resonance imaging (MRI) as a reference standard.
  
  
  METHODS
  Thirty patients with known or suspected ischemic heart disease underwent measurement of peak systolic longitudinal, radial, and circumferential Lagrangian strain with all 3 techniques using a 16-segment model. The extent of scar tissue in each segment was determined using contrast-enhanced MRI.
  
  
  RESULTS
  The measurement of myocardial strain in all 3 directions was highly feasible with both VVI and AFI. Longitudinal strain was underestimated by both VVI (-11 +/- 8%; P < .01) and AFI (-12 +/- 6%; P < .01) in comparison with HARP MRI (-14 +/- 5%), and radial strain was underestimated by VVI (14 +/- 18% vs 23 +/- 7%; P < .01). All strain measurements with AFI showed better correlation and agreement with HARP MRI compared with VVI. Circumferential strain with AFI had the greatest accuracy (area under the receiver operating characteristic curve = 0.74, P < .001) for the prediction of scar tissue on MRI.
  
  
  CONCLUSIONS
  Two-dimensional strain measured with AFI has significantly better accuracy than VVI. Circumferential strain with AFI has the best discriminative ability for the detection of regional myocardial dysfunction.
authors.affiliation: Department of Medicine, University of Queensland, Brisbane, Australia.
authors.forename: Manish
authors.initials: M
authors.lastname: Bansal
authors.forename: Goo-Yeong
authors.initials: GY
authors.lastname: Cho
authors.forename: Jonathan
authors.initials: J
authors.lastname: Chan
authors.forename: Rodel
authors.initials: R
authors.lastname: Leano
authors.forename: Brian A
authors.initials: BA
authors.lastname: Haluska
authors.forename: Thomas H
authors.initials: TH
authors.lastname: Marwick
mesh_terms: D004452:Echocardiography / Q000379:methods*; D054459:Elasticity Imaging Techniques / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000150:complications* / Q000175:diagnosis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D018487:Ventricular Dysfunction, Left / Q000150:complications* / Q000175:diagnosis*