title: Cardiovascular magnetic resonance feature-tracking assessment of myocardial mechanics: Intervendor agreement and considerations regarding reproducibility.
abstract: OBJECTIVE
  To assess intervendor agreement of cardiovascular magnetic resonance feature tracking (CMR-FT) and to study the impact of repeated measures on reproducibility.
  
  
  METHODS
  Ten healthy volunteers underwent cine imaging in short-axis orientation at rest and with dobutamine stimulation (10 and 20 μg/kg/min). All images were analysed three times using two types of software (TomTec, Unterschleissheim, Germany and Circle, cvi(42), Calgary, Canada) to assess global left ventricular circumferential (Ecc) and radial (Err) strains and torsion. Differences in intra- and interobserver variability within and between software types were assessed based on single and averaged measurements (two and three repetitions with subsequent averaging of results, respectively) as determined by Bland-Altman analysis, intraclass correlation coefficients (ICC), and coefficient of variation (CoV).
  
  
  RESULTS
  Myocardial strains and torsion significantly increased on dobutamine stimulation with both types of software (p<0.05). Resting Ecc and torsion as well as Ecc values during dobutamine stimulation were lower measured with Circle (p<0.05). Intra- and interobserver variability between software types was lowest for Ecc (ICC 0.81 [0.63-0.91], 0.87 [0.72-0.94] and CoV 12.47% and 14.3%, respectively) irrespective of the number of analysis repetitions. Err and torsion showed higher variability that markedly improved for torsion with repeated analyses and to a lesser extent for Err. On an intravendor level TomTec showed better reproducibility for Ecc and torsion and Circle for Err.
  
  
  CONCLUSIONS
  CMR-FT strain and torsion measurements are subject to considerable intervendor variability, which can be reduced using three analysis repetitions. For both vendors, Ecc qualifies as the most robust parameter with the best agreement, albeit lower Ecc values obtained using Circle, and warrants further investigation of incremental clinical merit.
authors.affiliation: Department of Cardiology and Pneumology, Georg-August University, Göttingen, Germany; DZHK (German Centre for Cardiovascular Research), Germany; Division of Imaging Sciences and Biomedical Engineering, The Rayne Institute, St. Thomas' Hospital, King's College London, London, UK. Electronic address: andreas_schuster@gmx.net.
authors.forename: A
authors.initials: A
authors.lastname: Schuster
authors.affiliation: Institute for Diagnostic and Interventional Radiology, Georg-August University, Göttingen, Germany.
authors.forename: V-C
authors.initials: VC
authors.lastname: Stahnke
authors.affiliation: Department of Cardiology and Pneumology, Georg-August University, Göttingen, Germany; DZHK (German Centre for Cardiovascular Research), Germany; Institute for Diagnostic and Interventional Radiology, Georg-August University, Göttingen, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Unterberg-Buchwald
authors.affiliation: DZHK (German Centre for Cardiovascular Research), Germany; Institute for Diagnostic and Interventional Radiology, Georg-August University, Göttingen, Germany.
authors.forename: J T
authors.initials: JT
authors.lastname: Kowallick
authors.affiliation: Division of Imaging Sciences and Biomedical Engineering, The Rayne Institute, St. Thomas' Hospital, King's College London, London, UK; Department of Computer Science, University of Oxford, Oxford, UK.
authors.forename: P
authors.initials: P
authors.lastname: Lamata
authors.affiliation: Department of Paediatric Cardiology and Intensive Care Medicine, Georg-August-University Göttingen, Göttingen, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Steinmetz
authors.affiliation: Children's Hospital and Medical Center Joint Division of Pediatric Cardiology, University of Nebraska / Creighton University, Omaha, NE, USA.
authors.forename: S
authors.initials: S
authors.lastname: Kutty
authors.affiliation: DZHK (German Centre for Cardiovascular Research), Germany; Institute for Diagnostic and Interventional Radiology, Georg-August University, Göttingen, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Fasshauer
authors.affiliation: DZHK (German Centre for Cardiovascular Research), Germany; Institute for Diagnostic and Interventional Radiology, Georg-August University, Göttingen, Germany.
authors.forename: W
authors.initials: W
authors.lastname: Staab
authors.affiliation: DZHK (German Centre for Cardiovascular Research), Germany; Institute for Diagnostic and Interventional Radiology, Georg-August University, Göttingen, Germany.
authors.forename: J M
authors.initials: JM
authors.lastname: Sohns
authors.affiliation: Department of Cardiology, Campus Benjamin Franklin, Charité Berlin, Hindenburgdamm 30, 12200 Berlin, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Bigalke
authors.affiliation: DZHK (German Centre for Cardiovascular Research), Germany; Institute for Diagnostic and Interventional Radiology, Georg-August University, Göttingen, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Ritter
authors.affiliation: Department of Cardiology and Pneumology, Georg-August University, Göttingen, Germany; DZHK (German Centre for Cardiovascular Research), Germany.
authors.forename: G
authors.initials: G
authors.lastname: Hasenfuß
authors.affiliation: Department of Paediatric Cardiology, Hannover Medical School, Hannover, Germany.
authors.forename: P
authors.initials: P
authors.lastname: Beerbaum
authors.affiliation: DZHK (German Centre for Cardiovascular Research), Germany; Institute for Diagnostic and Interventional Radiology, Georg-August University, Göttingen, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Lotz
mesh_terms: D000328:Adult; D002316:Cardiotonic Agents; D004280:Dobutamine; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012984:Software
chemical_list: D002316:Cardiotonic Agents; D004280:Dobutamine