title: Quantification of left ventricular torsion and diastolic recoil using cardiovascular magnetic resonance myocardial feature tracking.
abstract: OBJECTIVE
  Cardiovascular magnetic resonance feature tracking (CMR-FT) offers quantification of myocardial deformation from routine cine images. However, data using CMR-FT to quantify left ventricular (LV) torsion and diastolic recoil are not yet available. We therefore sought to evaluate the feasibility and reproducibility of CMR-FT to quantify LV torsion and peak recoil rate using an optimal anatomical approach.
  
  
  METHODS
  Short-axis cine stacks were acquired at rest and during dobutamine stimulation (10 and 20 µg · kg(-1) · min(-1)) in 10 healthy volunteers. Rotational displacement was analysed for all slices. A complete 3D-LV rotational model was developed using linear interpolation between adjacent slices. Torsion was defined as the difference between apical and basal rotation, divided by slice distance. Depending on the distance between the most apical (defined as 0% LV distance) and basal (defined as 100% LV distance) slices, four different models for the calculation of torsion were examined: Model-1 (25-75%), Model-2 (0-100%), Model-3 (25-100%) and Model-4 (0-75%). Analysis included subendocardial, subepicardial and global torsion and recoil rate (mean of subendocardial and subepicardial values).
  
  
  RESULTS
  Quantification of torsion and recoil rate was feasible in all subjects. There was no significant difference between the different models at rest. However, only Model-1 (25-75%) discriminated between rest and stress (Global Torsion: 2.7 ± 1.5° cm(-1), 3.6 ± 2.0° cm(-1), 5.1 ± 2.2° cm(-1), p<0.01; Global Recoil Rate: -30.1 ± 11.1° cm(-1) s(-1),-46.9 ± 15.0° cm(-1) s(-1),-68.9 ± 32.3° cm(-1) s(-1), p<0.01; for rest, 10 and 20 µg · kg(-)1 · min(-1) of dobutamine, respectively). Reproducibility was sufficient for all parameters as determined by Bland-Altman analysis, intraclass correlation coefficients and coefficient of variation.
  
  
  CONCLUSIONS
  CMR-FT based derivation of myocardial torsion and recoil rate is feasible and reproducible at rest and with dobutamine stress. Using an optimal anatomical approach measuring rotation at 25% and 75% apical and basal LV locations allows effective quantification of torsion and recoil dynamics. Application of these new measures of deformation by CMR-FT should next be explored in disease states.
authors.affiliation: Institute for Diagnostic and Interventional Radiology, Georg-August-University Göttingen, Göttingen, Germany; DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Göttingen, Germany.
authors.forename: Johannes T
authors.initials: JT
authors.lastname: Kowallick
authors.affiliation: Department of Computer Science, University of Oxford, Oxford, United Kingdom; Division of Imaging Sciences and Biomedical Engineering, The Rayne Institute, St. Thomas' Hospital, King's College London, London, United Kingdom.
authors.forename: Pablo
authors.initials: P
authors.lastname: Lamata
authors.affiliation: Papworth Hospital NHS Trust, Papworth Everard, Cambridgeshire, United Kingdom.
authors.forename: Shazia T
authors.initials: ST
authors.lastname: Hussain
authors.affiliation: Children's Hospital and Medical Center, University of Nebraska College of Medicine, Omaha, Nebraska, United States of America.
authors.forename: Shelby
authors.initials: S
authors.lastname: Kutty
authors.affiliation: Department of Pediatric Cardiology and Intensive Care Medicine, Georg-August-University Göttingen, Göttingen, Germany; DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Göttingen, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Steinmetz
authors.affiliation: Institute for Diagnostic and Interventional Radiology, Georg-August-University Göttingen, Göttingen, Germany; DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Göttingen, Germany.
authors.forename: Jan M
authors.initials: JM
authors.lastname: Sohns
authors.affiliation: Institute for Diagnostic and Interventional Radiology, Georg-August-University Göttingen, Göttingen, Germany; DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Göttingen, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Fasshauer
authors.affiliation: Institute for Diagnostic and Interventional Radiology, Georg-August-University Göttingen, Göttingen, Germany; DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Göttingen, Germany.
authors.forename: Wieland
authors.initials: W
authors.lastname: Staab
authors.affiliation: Department of Cardiology and Pneumology, Georg-August-University Göttingen, Göttingen, Germany; DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Göttingen, Germany.
authors.forename: Christina
authors.initials: C
authors.lastname: Unterberg-Buchwald
authors.affiliation: Division of Imaging Sciences and Biomedical Engineering, The Rayne Institute, St. Thomas' Hospital, King's College London, London, United Kingdom; Medizinische Klinik III, Kardiologie und Kreislauferkrankungen, Eberhard-Karls-Universität Tübingen, Tübingen, Germany.
authors.forename: Boris
authors.initials: B
authors.lastname: Bigalke
authors.affiliation: Institute for Diagnostic and Interventional Radiology, Georg-August-University Göttingen, Göttingen, Germany; DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Göttingen, Germany.
authors.forename: Joachim
authors.initials: J
authors.lastname: Lotz
authors.affiliation: Department of Cardiology and Pneumology, Georg-August-University Göttingen, Göttingen, Germany; DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Göttingen, Germany.
authors.forename: Gerd
authors.initials: G
authors.lastname: Hasenfuß
authors.affiliation: Department of Cardiology and Pneumology, Georg-August-University Göttingen, Göttingen, Germany; Division of Imaging Sciences and Biomedical Engineering, The Rayne Institute, St. Thomas' Hospital, King's College London, London, United Kingdom; DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Göttingen, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Schuster
mesh_terms: D000328:Adult; D000465:Algorithms; D003971:Diastole / Q000187:drug effects / Q000502:physiology*; D004280:Dobutamine / Q000494:pharmacology; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000378:metabolism*; D012399:Rotation; D054159:Torsion, Mechanical; D016277:Ventricular Function, Left / Q000187:drug effects / Q000502:physiology*; D055815:Young Adult
chemical_list: D004280:Dobutamine