title: Cardiovascular magnetic resonance myocardial feature tracking for quantitative viability assessment in ischemic cardiomyopathy.
abstract: BACKGROUND
  Low dose dobutamine stress magnetic resonance imaging is valuable to assess viability in patients with ischemic cardiomyopathy. Analysis is usually qualitative with considerable operator dependency. The aim of the current study was to investigate the feasibility of cine images derived quantitative cardiac magnetic resonance (CMR) myocardial feature tracking (FT) strain parameters to assess viability in patients with ischemic cardiomyopathy.
  
  
  METHODS
  15 consecutive patients with ischemic cardiomyopathy referred for viability assessment were studied at 3T at rest and during low dose dobutamine stress (5 and 10μg/kg/min of dobutamine). Subendocardial and subepicardial circumferential (Eccendo and Eccepi) and radial (Err) strains were assessed using steady state free precession (SSFP) cine images orientated in 3 short axis slices covering 16 myocardial segments.
  
  
  RESULTS
  Dysfunctional segments without scar (n=75) improved in all three strain parameters: Eccendo (Rest: -10.5±6.9; 5μg: -12.1±6.9; 10μg: -14.1±9.2; p<0.05), Eccepi (Rest: -7±4.8; 5μg: -8.2±5.5; 10μg: -9.1±5.9; p<0.05) and Err (Rest: 11.7±8.3; 5μg: 16±10.9; 10μg: 16.5±12.8; p<0.05). There was no response to dobutamine in dysfunctional segments with scar transmurality above 75% (n=6): Eccendo (Rest: -4.7±3.0; 5μg: -2.9±2.5; 10μg: -6.6±3.3; p=ns), Eccepi (Rest: -2.9±2.9; 5μg: -5.4±3.9; 10μg: -4.5±4.2; p=ns) and Err (Rest:9.5±5; 5μg:5.4±6.2; 10μg:4.9±3.3; p=ns). Circumferential strain (Eccendo, Eccepi) improved in all segments up to a transmurality of 75% (n=60; p<0.05). Err improved in segments <50% transmurality (n=45; p<0.05) and remained unchanged above 50% transmurality (n=21; p=ns).
  
  
  CONCLUSIONS
  CMR-FT is a novel technique, which detects quantitative wall motion derived from SSFP cine imaging at rest and with low dose dobutamine stress. CMR-FT holds promise of quantitative assessment of viability in patients with ischemic cardiomyopathy.
authors: Division of Imaging Sciences and Biomedical Engineering, The Rayne Institute, St. Thomas' Hospital, London, UK. andreas_schuster@gmx.net
authors: Andreas
authors: A
authors: Schuster
authors: Matthias
authors: M
authors: Paul
authors: Nuno
authors: N
authors: Bettencourt
authors: Geraint
authors: G
authors: Morton
authors: Amedeo
authors: A
authors: Chiribiri
authors: Masaki
authors: M
authors: Ishida
authors: Shazia
authors: S
authors: Hussain
authors: Roy
authors: R
authors: Jogiya
authors: Shelby
authors: S
authors: Kutty
authors: Boris
authors: B
authors: Bigalke
authors: Divaka
authors: D
authors: Perera
authors: Eike
authors: E
authors: Nagel
mesh_terms: D000368:Aged; D009202:Cardiomyopathies / Q000175:diagnosis* / Q000453:epidemiology*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods* / Q000592:standards; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000175:diagnosis* / Q000453:epidemiology*