title: Knee x-ray image analysis method for automated detection of osteoarthritis.
abstract: We describe a method for automated detection of radiographic osteoarthritis (OA) in knee X-ray images. The detection is based on the Kellgren-Lawrence (KL) classification grades, which correspond to the different stages of OA severity. The classifier was built using manually classified X-rays, representing the first four KL grades (normal, doubtful, minimal, and moderate). Image analysis is performed by first identifying a set of image content descriptors and image transforms that are informative for the detection of OA in the X-rays and assigning weights to these image features using Fisher scores. Then, a simple weighted nearest neighbor rule is used in order to predict the KL grade to which a given test X-ray sample belongs. The dataset used in the experiment contained 350 X-ray images classified manually by their KL grades. Experimental results show that moderate OA (KL grade 3) and minimal OA (KL grade 2) can be differentiated from normal cases with accuracy of 91.5% and 80.4%, respectively. Doubtful OA (KL grade 1) was detected automatically with a much lower accuracy of 57%. The source code developed and used in this study is available for free download at www.openmicroscopy.org.
authors.affiliation: Image Informatics and Computational Biology Unit, Laboratory of Genetics, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA. shamirl@mail.nih.gov
authors.forename: Lior
authors.initials: L
authors.lastname: Shamir
authors.forename: Shari M
authors.initials: SM
authors.lastname: Ling
authors.forename: William W
authors.initials: WW
authors.lastname: Scott
authors.forename: Angelo
authors.initials: A
authors.lastname: Bos
authors.forename: Nikita
authors.initials: N
authors.lastname: Orlov
authors.forename: Tomasz J
authors.initials: TJ
authors.lastname: Macura
authors.forename: D Mark
authors.initials: DM
authors.lastname: Eckley
authors.forename: Luigi
authors.initials: L
authors.lastname: Ferrucci
authors.forename: Ilya G
authors.initials: IG
authors.lastname: Goldberg