title: High-resolution 3-dimensional late gadolinium enhancement scar imaging in surgically corrected Tetralogy of Fallot: clinical feasibility of volumetric quantification and visualization.
abstract: BACKGROUND
  The extent of surgical scarring in Tetralogy of Fallot (TOF) may be a marker of adverse outcomes and provide substrate for ventricular arrhythmia. In this study we evaluate the feasibility of high resolution three dimensional (3D) late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) for volumetric scar quantification in patients with surgically corrected TOF.
  
  
  METHODS
  Fifteen consecutive patients underwent 3D LGE imaging with 3 Tesla CMR using a whole-heart, respiratory-navigated technique. A novel, signal-histogram based segmentation technique was tested for the quantification and modeling of surgical scar. Total scar volume was compared to the gold standard manual expert segmentation. The feasibility of segmented scar fusion to matched coronary CMR data for volumetric display was explored.
  
  
  RESULTS
  Image quality sufficient for 3D scar segmentation was acquired in fourteen patients. Mean patient age was 32.2 ± 11.9 years (range 21 to 57 years) with mean right ventricle (RV) ejection fraction (EF) of 53.9 ± 9.2% and mean RV end diastolic volume of 117.0 ± 41.5 mL/m². The mean total scar volume was 11.1 ± 8.2 mL using semi-automated 3D segmentation with excellent correlation to manual expert segmentation (r = 0.99, bias = 0.89 mL, 95% CI -1.66 to 3.44). The mean segmentation time was significantly reduced using the novel semi-automated segmentation technique (10.1 ± 2.6 versus 45.8 ± 12.6 minutes). Excellent intra-observer and good inter-observer reproducibility was observed.
  
  
  CONCLUSIONS
  3D high resolution LGE imaging with semi-automated scar segmentation is clinically feasible among patients with surgically corrected TOF and shows excellent accuracy and reproducibility. This approach may offer a valuable clinical tool for risk prediction and procedural planning among this growing population.
authors.affiliation: Imaging Laboratories, Robarts Research Institute, Western University, London, Ontario, Canada. jstirrat2015@meds.uwo.ca.
authors.forename: John
authors.initials: J
authors.lastname: Stirrat
authors.affiliation: Imaging Laboratories, Robarts Research Institute, Western University, London, Ontario, Canada. mrajchl@robarts.ca.
authors.forename: Martin
authors.initials: M
authors.lastname: Rajchl
authors.affiliation: Division of Cardiology, Department of Medicine, Western University, Calgary, Canada. Lynn.Bergin@lhsc.on.ca.
authors.forename: Lynn
authors.initials: L
authors.lastname: Bergin
authors.affiliation: Cardiac Imaging Centre, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada. David.Patton@albertahealthservices.ca.|Department of Pediatrics, University of Calgary, Calgary, Alberta, Canada. David.Patton@albertahealthservices.ca.
authors.forename: David J
authors.initials: DJ
authors.lastname: Patton
authors.affiliation: Imaging Laboratories, Robarts Research Institute, Western University, London, Ontario, Canada. tpeters@robarts.ca.
authors.forename: Terry
authors.initials: T
authors.lastname: Peters
authors.affiliation: Division of Cardiology, Department of Medicine, Western University, Calgary, Canada. jawhit@ucalgary.ca.|Cardiac Imaging Centre, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada. jawhit@ucalgary.ca.|Division of Cardiology, Department of Medicine, University of Calgary, Calgary, Alberta, Canada. jawhit@ucalgary.ca.
authors.forename: James A
authors.initials: JA
authors.lastname: White
mesh_terms: D000328:Adult; D001331:Automation; D006348:Cardiac Surgical Procedures; D002921:Cicatrix / Q000175:diagnosis* / Q000209:etiology / Q000473:pathology; D003287:Contrast Media; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000473:pathology*; D015588:Observer Variation; D009942:Organometallic Compounds; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D013771:Tetralogy of Fallot / Q000150:complications / Q000175:diagnosis / Q000601:surgery*; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; C090600:gadobutrol