title: Myocardial feature tracking reduces observer-dependence in low-dose dobutamine stress cardiovascular magnetic resonance.
abstract: OBJECTIVE
  To determine whether quantitative wall motion assessment by CMR myocardial feature tracking (CMR-FT) would reduce the impact of observer experience as compared to visual analysis in patients with ischemic cardiomyopathy (ICM).
  
  
  METHODS
  15 consecutive patients with ICM referred for assessment of hibernating myocardium were studied at 3 Tesla using SSFP cine images at rest and during low dose dobutamine stress (5 and 10 μg/kg/min of dobutamine). Conventional visual, qualitative analysis was performed independently and blinded by an experienced and an inexperienced reader, followed by post-processing of the same images by CMR-FT to quantify subendocardial and subepicardial circumferential (Eccendo and Eccepi) and radial (Err) strain. Receiver operator characteristics (ROC) were assessed for each strain parameter and operator to detect the presence of inotropic reserve as visually defined by the experienced observer.
  
  
  RESULTS
  141 segments with wall motion abnormalities at rest were eligible for the analysis. Visual scoring of wall motion at rest and during dobutamine was significantly different between the experienced and the inexperienced observer (p<0.001). All strain values (Eccendo, Eccepi and Err) derived during dobutamine stress (5 and 10 μg/kg/min) showed similar diagnostic accuracy for the detection of contractile reserve for both operators with no differences in ROC (p>0.05). Eccendo was the most accurate (AUC of 0.76, 10 μg/kg/min of dobutamine) parameter. Diagnostic accuracy was worse for resting strain with differences between operators for Eccendo and Eccepi (p<0.05) but not Err (p>0.05).
  
  
  CONCLUSIONS
  Whilst visual analysis remains highly dependent on operator experience, quantitative CMR-FT analysis of myocardial wall mechanics during DS-CMR provides diagnostic accuracy for the detection of inotropic reserve regardless of operator experience and hence may improve diagnostic robustness of low-dose DS-CMR in clinical practice.
authors.affiliation: Department of Cardiology and Pulmonology, Georg-August-University and German Center for Cardiovascular Research (DZHK, Partner Site), Göttingen, Germany; King's College London British Heart Foundation (BHF) Centre of Excellence; National Institute of Health Research (NIHR) Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust; Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC) Medical Engineering Centre; Division of Imaging Sciences and Biomedical Engineering; The Rayne Institute, St. Thomas´ Hospital, London, United Kingdom.
authors.forename: Andreas
authors.initials: A
authors.lastname: Schuster
authors.affiliation: King's College London British Heart Foundation (BHF) Centre of Excellence; National Institute of Health Research (NIHR) Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust; Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC) Medical Engineering Centre; Division of Imaging Sciences and Biomedical Engineering; The Rayne Institute, St. Thomas´ Hospital, London, United Kingdom.
authors.forename: Matthias
authors.initials: M
authors.lastname: Paul
authors.affiliation: Cardiology Department-Centro Hospitalar de Gaia/Espinho, Porto, Portugal.
authors.forename: Nuno
authors.initials: N
authors.lastname: Bettencourt
authors.affiliation: King's College London British Heart Foundation (BHF) Centre of Excellence; National Institute of Health Research (NIHR) Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust; Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC) Medical Engineering Centre; Division of Imaging Sciences and Biomedical Engineering; The Rayne Institute, St. Thomas´ Hospital, London, United Kingdom.
authors.forename: Shazia T
authors.initials: ST
authors.lastname: Hussain
authors.affiliation: King's College London British Heart Foundation (BHF) Centre of Excellence; National Institute of Health Research (NIHR) Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust; Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC) Medical Engineering Centre; Division of Imaging Sciences and Biomedical Engineering; The Rayne Institute, St. Thomas´ Hospital, London, United Kingdom.
authors.forename: Geraint
authors.initials: G
authors.lastname: Morton
authors.affiliation: Joint Division of Pediatric Cardiology, University of Nebraska/Creighton University, Children's Hospital and Medical Center, Omaha, Nebraska, United States of America.
authors.forename: Shelby
authors.initials: S
authors.lastname: Kutty
authors.affiliation: King's College London British Heart Foundation (BHF) Centre of Excellence; National Institute of Health Research (NIHR) Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust; Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC) Medical Engineering Centre; Division of Imaging Sciences and Biomedical Engineering; The Rayne Institute, St. Thomas´ Hospital, London, United Kingdom; Department of Cardiology, Campus Benjamin Franklin, Charité Berlin, Hindenburgdamm 30, Berlin, Germany.
authors.forename: Boris
authors.initials: B
authors.lastname: Bigalke
authors.affiliation: King's College London British Heart Foundation (BHF) Centre of Excellence; National Institute of Health Research (NIHR) Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust; Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC) Medical Engineering Centre; Division of Imaging Sciences and Biomedical Engineering; The Rayne Institute, St. Thomas´ Hospital, London, United Kingdom.
authors.forename: Amedeo
authors.initials: A
authors.lastname: Chiribiri
authors.affiliation: King's College London British Heart Foundation (BHF) Centre of Excellence; National Institute of Health Research (NIHR) Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust; Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC) Medical Engineering Centre; Division of Imaging Sciences and Biomedical Engineering; The Rayne Institute, St. Thomas´ Hospital, London, United Kingdom; King's College London BHF Centre of Excellence, NIHR Biomedical Research Centre and Department of Cardiology, Guy's and St. Thomas' NHS Foundation Trust, London, United Kingdom.
authors.forename: Divaka
authors.initials: D
authors.lastname: Perera
authors.affiliation: King's College London British Heart Foundation (BHF) Centre of Excellence; National Institute of Health Research (NIHR) Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust; Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC) Medical Engineering Centre; Division of Imaging Sciences and Biomedical Engineering; The Rayne Institute, St. Thomas´ Hospital, London, United Kingdom.
authors.forename: Eike
authors.initials: E
authors.lastname: Nagel
authors.affiliation: King's College London British Heart Foundation (BHF) Centre of Excellence; National Institute of Health Research (NIHR) Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust; Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC) Medical Engineering Centre; Division of Imaging Sciences and Biomedical Engineering; The Rayne Institute, St. Thomas´ Hospital, London, United Kingdom; Department of Paediatric Cardiology, Hannover Medical School, Hannover, Germany.
authors.forename: Philipp
authors.initials: P
authors.lastname: Beerbaum
mesh_terms: D000368:Aged; D004280:Dobutamine / Q000494:pharmacology*; D005260:Female; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction / Q000187:drug effects*; D009206:Myocardium
chemical_list: D004280:Dobutamine
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