title: Fully automated segmentation of cartilage from the MR images of knee using a multi-atlas and local structural analysis method.
abstract: OBJECTIVE
  To develop a fully automated method to segment cartilage from the magnetic resonance (MR) images of knee and to evaluate the performance of the method on a public, open dataset.
  
  
  METHODS
  The segmentation scheme consisted of three procedures: multiple-atlas building, applying a locally weighted vote (LWV), and region adjustment. In the atlas building procedure, all training cases were registered to a target image by a nonrigid registration scheme and the best matched atlases selected. A LWV algorithm was applied to merge the information from these atlases and generate the initial segmentation result. Subsequently, for the region adjustment procedure, the statistical information of bone, cartilage, and surrounding regions was computed from the initial segmentation result. The statistical information directed the automated determination of the seed points inside and outside bone regions for the graph-cut based method. Finally, the region adjustment was conducted by the revision of outliers and the inclusion of abnormal bone regions.
  
  
  RESULTS
  A total of 150 knee MR images from a public, open dataset (available atwww.ski10.org) were used for the development and evaluation of this approach. The 150 cases were divided into the training set (100 cases) and the test set (50 cases). The cartilages were segmented successfully in all test cases in an average of 40 min computation time. The average dice similarity coefficient was 71.7%±8.0% for femoral and 72.4%±6.9% for tibial cartilage.
  
  
  CONCLUSIONS
  The authors have developed a fully automated segmentation program for knee cartilage from MR images. The performance of the program based on 50 test cases was highly promising.
authors.affiliation: Department of Radiology, University of Pittsburgh, Pittsburgh, Pennsylvania 15213.
authors.forename: June-Goo
authors.initials: JG
authors.lastname: Lee
authors.affiliation: Department of Radiology, University of Pittsburgh, Pittsburgh, Pennsylvania 15213.
authors.forename: Serter
authors.initials: S
authors.lastname: Gumus
authors.affiliation: Department of Radiology, University of Pittsburgh, Pittsburgh, Pennsylvania 15213.
authors.forename: Chan Hong
authors.initials: CH
authors.lastname: Moon
authors.affiliation: Division of Rheumatology, University of Arizona Arthritis Center, Tucson, Arizona 85716.
authors.forename: C Kent
authors.initials: CK
authors.lastname: Kwoh
authors.affiliation: Department of Radiology, University of Pittsburgh, Pittsburgh, Pennsylvania 15213.
authors.forename: Kyongtae Ty
authors.initials: KT
authors.lastname: Bae
mesh_terms: D022126:Access to Information; D000465:Algorithms; D001271:Atlases as Topic; D002356:Cartilage / Q000033:anatomy & histology* / Q000473:pathology; D066264:Datasets as Topic; D005269:Femur / Q000033:anatomy & histology / Q000473:pathology; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D020407:Internet; D007717:Knee / Q000033:anatomy & histology* / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D010363:Pattern Recognition, Automated / Q000379:methods*; D013977:Tibia / Q000033:anatomy & histology / Q000473:pathology; D013995:Time