title: Determination of transmural, endocardial, and epicardial radial strain and strain rate from phase contrast MR velocity data.
abstract: OBJECTIVE
  To develop a method for computing radial strain (epsilon) and strain rate (SR) from phase contrast magnetic resonance (PCMR) myocardial tissue velocity data.
  
  
  METHODS
  PCMR tissue velocity maps were acquired at basal and mid-short-axis slices in the myocardium in 10 healthy volunteers. An algorithm for computing radial strain and SR from PCMR tissue velocity data was developed. PCMR strain values were compared to values computed independently from contours drawn on cine steady-state free procession (SSFP) images. Peak endocardial and epicardial strain and SR values from PCMR data were compared.
  
  
  RESULTS
  Excellent agreement was observed between peak strain values computed by PCMR and cine SSFP contours (38.1 +/- 5.4% vs. 38.1 +/- 6.2%; P = not significant [NS]). The presence of an endocardial-epicardial gradient was demonstrated in both strain and SR: peak endocardial values were larger than peak epicardial values in the basal and mid-short-axis slices (P < 0.05).
  
  
  CONCLUSIONS
  This study presents a method for determining radial strain and SR values from PCMR velocity data. This technique illustrates a difference in strain and SR across the myocardium with peak endocardial values being greater than peak epicardial values.
authors.affiliation: Department of Biomedical Engineering, Georgia Institute of Technology/Emory University, Atlanta, GA 30322, USA. jana.delfino@gatech.edu
authors.forename: Jana G
authors.initials: JG
authors.lastname: Delfino
authors.forename: Brandon K
authors.initials: BK
authors.lastname: Fornwalt
authors.forename: Robert L
authors.initials: RL
authors.lastname: Eisner
authors.forename: Angel R
authors.initials: AR
authors.lastname: Leon
authors.forename: John N
authors.initials: JN
authors.lastname: Oshinski
mesh_terms: D000328:Adult; D004699:Endocardium / Q000502:physiology; D005260:Female; D006321:Heart / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D010496:Pericardium / Q000502:physiology