title: Myocardial strain measurement with feature-tracking cardiovascular magnetic resonance: normal values.
abstract: OBJECTIVE
  Myocardial deformation is a key to clinical decision-making. Feature-tracking cardiovascular magnetic resonance (FT-CMR) provides quantification of motion and strain using standard steady-state in free-precession (SSFP) imaging, which is part of a routine CMR left ventricular (LV) study protocol. An accepted definition of a normal range is essential if this technique is to enter the clinical arena.
  
  
  RESULTS
  One hundred healthy individuals, with 10 men and women in each of 5 age deciles from 20 to 70 years, without a history of cardiovascular disease, diabetes, renal impairment, or family history of cardiovascular disease, and with a normal stress echocardiogram, underwent FT-CMR assessment of LV myocardial strain and strain rate using SSFP cines.Peak systolic longitudinal strain (Ell) was -21.3 ± 4.8%, peak systolic circumferential strain (Ecc) was -26.1 ± 3.8%, and peak systolic radial strain (Err) was 39.8 ± 8.3%. On Bland-Altman analyses, peak systolic Ecc had the best inter-observer agreement (bias 0.63 ± 1.29% and 95% CI -1.90 to 3.16) and peak systolic Err the least inter-observer agreement (bias 0.13 ± 6.41 and 95% CI -12.44 to 12.71). There was an increase in the magnitude of peak systolic Ecc with advancing age, which was greatest in subjects over the age of 50 years (R(2) = 0.11, P = 0.003). There were significant gender differences (P < 0.001) in peak systolic Ell, with a greater magnitude of deformation in females (-22.7%) than in males (-19.3%).
  
  
  CONCLUSIONS
  Normal values for myocardial strain measurements using FT-CMR are provided. All circumferential and longitudinal based variables had excellent intra- and inter-observer variability.
authors.affiliation: Department of Cardiology, The Queen Elizabeth Hospital Birmingham, Mindelsohn Way, Edgbaston, Birmingham B15 2WB, UK Centre for Cardiovascular Sciences, University of Birmingham, Birmingham B15 2TT, UK.
authors.forename: Robin J
authors.initials: RJ
authors.lastname: Taylor
authors.affiliation: Department of Cardiology, The Queen Elizabeth Hospital Birmingham, Mindelsohn Way, Edgbaston, Birmingham B15 2WB, UK Centre for Cardiovascular Sciences, University of Birmingham, Birmingham B15 2TT, UK.
authors.forename: William E
authors.initials: WE
authors.lastname: Moody
authors.affiliation: Department of Cardiology, The Queen Elizabeth Hospital Birmingham, Mindelsohn Way, Edgbaston, Birmingham B15 2WB, UK Centre for Cardiovascular Sciences, University of Birmingham, Birmingham B15 2TT, UK.
authors.forename: Fraz
authors.initials: F
authors.lastname: Umar
authors.affiliation: Department of Cardiology, The Queen Elizabeth Hospital Birmingham, Mindelsohn Way, Edgbaston, Birmingham B15 2WB, UK Centre for Cardiovascular Sciences, University of Birmingham, Birmingham B15 2TT, UK.
authors.forename: Nicola C
authors.initials: NC
authors.lastname: Edwards
authors.affiliation: Centre for Cardiovascular Sciences, University of Birmingham, Birmingham B15 2TT, UK.
authors.forename: Tiffany J
authors.initials: TJ
authors.lastname: Taylor
authors.affiliation: Bakken Research Center, Medtronic, Inc., Maastricht, Netherlands.
authors.forename: Berthold
authors.initials: B
authors.lastname: Stegemann
authors.affiliation: Department of Cardiology, The Queen Elizabeth Hospital Birmingham, Mindelsohn Way, Edgbaston, Birmingham B15 2WB, UK Centre for Cardiovascular Sciences, University of Birmingham, Birmingham B15 2TT, UK.
authors.forename: John N
authors.initials: JN
authors.lastname: Townend
authors.affiliation: Department of Cardiology, Nationwide Children's Hospital, Columbus, OH, USA.
authors.forename: Kan N
authors.initials: KN
authors.lastname: Hor
authors.affiliation: Department of Cardiology, The Queen Elizabeth Hospital Birmingham, Mindelsohn Way, Edgbaston, Birmingham B15 2WB, UK Centre for Cardiovascular Sciences, University of Birmingham, Birmingham B15 2TT, UK.
authors.forename: Richard P
authors.initials: RP
authors.lastname: Steeds
authors.affiliation: The Christ Hospital Heart and Vascular Center, Cincinnati, OH, USA.
authors.forename: Wojciech
authors.initials: W
authors.lastname: Mazur
authors.affiliation: Department of Cardiology, The Queen Elizabeth Hospital Birmingham, Mindelsohn Way, Edgbaston, Birmingham B15 2WB, UK Centre for Cardiovascular Sciences, University of Birmingham, Birmingham B15 2TT, UK cardiologists@hotmail.com.
authors.forename: Francisco
authors.initials: F
authors.lastname: Leyva
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction / Q000502:physiology*; D012016:Reference Values; D015203:Reproducibility of Results
keywords: cardiovascular magnetic resonance; feature tracking; inter-study variability; normal values; strain