title: Semi-automated myocardial segmentation of bright blood multi-gradient echo images improves reproducibility of myocardial contours and T2* determination.
abstract: OBJECTIVE
  Early detection of iron loading is affected by the reproducibility of myocardial contour assessment. A novel semi-automatic myocardial segmentation method is presented on contrast-optimized composite images and compared to the results of manual drawing.
  
  
  METHODS
  Fifty-one short-axis slices at basal, mid-ventricular and apical locations from 17 patients were acquired by bright blood multi-gradient echo MRI. Four observers produced semi-automatic and manual myocardial contours on contrast-optimized composite images. The semi-automatic segmentation method relies on vector field convolution active contours to generate the endocardial contour. After creating radial pixel clusters on the myocardial wall, a combination of pixel-wise coefficient of variance (CoV) assessment and k-means clustering establishes the epicardial contour for each segment.
  
  
  RESULTS
  Compared to manual drawing, semi-automatic myocardial segmentation lowers the variability of T2* quantification within and between observers (CoV of 12.05 vs. 13.86% and 14.43 vs. 16.01%) by improving contour reproducibility (P < 0.001). In the presence of iron loading, semi-automatic segmentation also lowers the T2* variability within and between observers (CoV of 13.14 vs. 15.19% and 15.91 vs. 17.28%).
  
  
  CONCLUSIONS
  Application of semi-automatic myocardial segmentation on contrast-optimized composite images improves the reproducibility of T2* quantification.
authors.affiliation: Center for Medical Imaging-North East Netherlands, University of Groningen, University Medical Center Groningen, EB45, 30001, 9700 RB, Groningen, The Netherlands. p.triadyaksa@umcg.nl.|Department of Physics, Diponegoro University, Sudharto Street, Semarang, 50275, Indonesia. p.triadyaksa@umcg.nl.
authors.forename: Pandji
authors.identifier: http://orcid.org/0000-0001-7536-3592
authors.initials: P
authors.lastname: Triadyaksa
authors.affiliation: Center for Medical Imaging-North East Netherlands, University of Groningen, University Medical Center Groningen, EB45, 30001, 9700 RB, Groningen, The Netherlands.|Department of Radiology, University of Groningen, University Medical Center Groningen, EB45, 30001, 9700 RB, Groningen, The Netherlands.
authors.forename: Niek H J
authors.initials: NHJ
authors.lastname: Prakken
authors.affiliation: Department of Radiology, University of Groningen, University Medical Center Groningen, EB45, 30001, 9700 RB, Groningen, The Netherlands.
authors.forename: Jelle
authors.initials: J
authors.lastname: Overbosch
authors.affiliation: Department of Radiology, University of Groningen, University Medical Center Groningen, EB45, 30001, 9700 RB, Groningen, The Netherlands.
authors.forename: Robin B
authors.initials: RB
authors.lastname: Peters
authors.affiliation: Department of Radiology, University of Groningen, University Medical Center Groningen, EB45, 30001, 9700 RB, Groningen, The Netherlands.
authors.forename: J Martijn
authors.initials: JM
authors.lastname: van Swieten
authors.affiliation: Center for Medical Imaging-North East Netherlands, University of Groningen, University Medical Center Groningen, EB45, 30001, 9700 RB, Groningen, The Netherlands.
authors.forename: Matthijs
authors.initials: M
authors.lastname: Oudkerk
authors.affiliation: Center for Medical Imaging-North East Netherlands, University of Groningen, University Medical Center Groningen, EB45, 30001, 9700 RB, Groningen, The Netherlands.|Department of Radiology, University of Groningen, University Medical Center Groningen, EB45, 30001, 9700 RB, Groningen, The Netherlands.
authors.forename: Paul E
authors.initials: PE
authors.lastname: Sijens
mesh_terms: D000465:Algorithms; D009202:Cardiomyopathies / Q000000981:diagnostic imaging*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D019190:Iron Overload / Q000000981:diagnostic imaging*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D010363:Pattern Recognition, Automated / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013382:Subtraction Technique
keywords: Bright blood myocardial T2*; Iron loading; Magnetic resonance imaging; Vector field convolution active contour; k-Means clustering