title: Automated liver stiffness measurements with magnetic resonance elastography.
abstract: OBJECTIVE
  To provide a fully automated algorithm for obtaining stiffness measurements from hepatic magnetic resonance elastography (MRE) images that are consistent with measurements performed by expert readers.
  
  
  METHODS
  An initial liver contour was found using an adaptive threshold and expanded using an active contour to select a homogeneous area of the liver. The confidence map generated during the stiffness calculation was used to select a region of reliable wave propagation. The average stiffness within the automatically generated region of interest (ROI) was compared to measurements by two trained readers in a set of 88 clinical test cases ranging from healthy to severely fibrotic.
  
  
  RESULTS
  The stiffness measurements reported by the readers differed by -6.76% ± 22.8% (95% confidence) and had an intraclass correlation coefficient (ICC) of 0.972 (P < 0.05). The algorithm and the more experienced reader differed by 4.32% ± 14.9 with an ICC of 0.987.
  
  
  CONCLUSIONS
  The automated algorithm performed reliably, even though MRE acquisitions often have motion artifacts present. The correlation between the automated measurements and those from the trained readers was superior to the correlation between the readers.
authors.affiliation: Mayo Graduate School, Mayo Clinic, Rochester, Minnesota 55902, USA.
authors.forename: Bogdan
authors.initials: B
authors.lastname: Dzyubak
authors.forename: Kevin
authors.initials: K
authors.lastname: Glaser
authors.forename: Meng
authors.initials: M
authors.lastname: Yin
authors.forename: Jayant
authors.initials: J
authors.lastname: Talwalkar
authors.forename: Jun
authors.initials: J
authors.lastname: Chen
authors.forename: Armando
authors.initials: A
authors.lastname: Manduca
authors.forename: Richard L
authors.initials: RL
authors.lastname: Ehman
mesh_terms: D000465:Algorithms; D055119:Elastic Modulus; D054459:Elasticity Imaging Techniques / Q000379:methods*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008099:Liver / Q000473:pathology* / Q000503:physiopathology*; D008107:Liver Diseases / Q000473:pathology* / Q000503:physiopathology*; D010363:Pattern Recognition, Automated / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
keywords: MR elastography; automation; hepatic fibrosis; liver; segmentation