title: Trabecular homogeneity index derived from plain radiograph to evaluate bone quality.
abstract: Radiographic texture analysis has been developed lately to improve the assessment of bone architecture as a determinant of bone quality. We validate here an algorithm for the evaluation of trabecular homogeneity index (HI) in the proximal femur from hip radiographs, with a focus on the impact of the principal compressive system of the trabecular bone, and evaluate its correlation with femoral strength, bone mineral density (BMD), and volumetric trabecular structure parameters. A semiautomatic custom-made algorithm was applied to calculate the HI in the femoral neck and trochanteric areas from radiographs of 178 femoral bone specimens (mean age 79.3 ± 10.4 years). Corresponding neck region was selected in CT scans to calculate volumetric parameters of trabecular structure. The site-specific BMDs were assessed from dual-energy X-ray absorptiometry (DXA), and the femoral strength was experimentally tested in side-impact configuration. Regression analysis was performed between the HI and biomechanical femoral strength, BMD, and volumetric parameters. The correlation between HI and failure load was R(2)  = 0.50; this result was improved to R(2)  = 0.58 for cervical fractures alone. The discrimination of bones with high risk of fractures (load <3000 N) was similar for HI and BMD (AUC = 0.87). Regression analysis between the HIs versus site-specific BMDs yielded R(2)  = 0.66 in neck area, R(2)  = 0.60 in trochanteric area, and an overall of R(2)  = 0.66 for the total hip. Neck HI and BMD correlated significantly with volumetric structure parameters. We present here a method to assess HI that can explain 50% of an experimental failure load and determines bones with high fracture risk with similar accuracy as BMD. The HI also had good correlation with DXA and computed tomography-derived data.
authors.affiliation: Department of Medical Technology, University of Oulu, Oulu, Finland.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Thevenot
authors.forename: Jukka
authors.initials: J
authors.lastname: Hirvasniemi
authors.forename: Mikko
authors.initials: M
authors.lastname: Finnilä
authors.forename: Pasi
authors.initials: P
authors.lastname: Pulkkinen
authors.forename: Volker
authors.initials: V
authors.lastname: Kuhn
authors.forename: Thomas
authors.initials: T
authors.lastname: Link
authors.forename: Felix
authors.initials: F
authors.lastname: Eckstein
authors.forename: Timo
authors.initials: T
authors.lastname: Jämsä
authors.forename: Simo
authors.initials: S
authors.lastname: Saarakkala
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015519:Bone Density / Q000502:physiology; D001842:Bone and Bones / Q000000981:diagnostic imaging* / Q000502:physiology*; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging / Q000502:physiology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D009333:Neck / Q000000981:diagnostic imaging / Q000502:physiology; D012372:ROC Curve; D012044:Regression Analysis; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed
keywords: CT SCAN; DXA; HOMOGENEITY INDEX; RADIOGRAPH; STRUCTURE ANALYSIS