title: Automatic assessment of the knee alignment angle on full-limb radiographs.
abstract: In this study a fully automatic assessment of the knee alignment angles in full-limb radiographs was developed and compared to manual standard of reference measurements in a prospective manner. The data consisted of 28 knees which were gathered from total-leg radiographs of 15 patients (12 males and 3 females with a mean age of 29.4+/-6.9 years) consecutively. For statistical evaluation, a leave-one-out cross-validation was performed. The pattern recognition and consequently the fully automatic assessment were successful in all patients. The automatically measured angles highly correlated with the standard of reference (r=0.989). The mean absolute difference was 0.578 degrees (95% CI: 0.399-0.757 degrees ). 82% of the angles differed less than 1 degrees from the standard of reference, 46% differed less than 0.5 degrees and 31% differed less than 0.2 degrees . The automatic method showed a high agreement between repeated measurements (+0.515 degrees to -0.429 degrees ). The automatic assessment of alignment angles in full-limb radiographs were equal to the manual assessment. No measurement related user interaction was necessary to achieve results.
authors.affiliation: Department of Radiology, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria. negar.fakhrai@meduniwien.ac.at
authors.forename: Negar
authors.initials: N
authors.lastname: Fakhrai
authors.forename: Peter
authors.initials: P
authors.lastname: Widhalm
authors.forename: Catharina
authors.initials: C
authors.lastname: Chiari
authors.forename: Michael
authors.initials: M
authors.lastname: Weber
authors.forename: Georg
authors.initials: G
authors.lastname: Langs
authors.forename: René
authors.initials: R
authors.lastname: Donner
authors.forename: Helmut
authors.initials: H
authors.lastname: Ringl
authors.forename: Marion
authors.initials: M
authors.lastname: Jantsch
authors.forename: Philipp
authors.initials: P
authors.lastname: Peloschek
mesh_terms: D000328:Adult; D001331:Automation; D005260:Female; D006801:Humans; D016916:Joint Deformities, Acquired / Q000000981:diagnostic imaging*; D007866:Leg / Q000000981:diagnostic imaging*; D008297:Male; D011446:Prospective Studies; D011859:Radiography; D012984:Software