title: Estimating the density of femoral head trabecular bone from hip fracture patients using computed tomography scan data.
abstract: The purpose of this study was to compare computed tomography density (ρCT) obtained using typical clinical computed tomography scan parameters to ash density (ρash), for the prediction of densities of femoral head trabecular bone from hip fracture patients. An experimental study was conducted to investigate the relationships between ρashand ρCTand between each of these densities and ρbulkand ρdry. Seven human femoral heads from hip fracture patients were computed tomography-scanned ex vivo, and 76 cylindrical trabecular bone specimens were collected. Computed tomography density was computed from computed tomography images by using a calibration Hounsfield units-based equation, whereas ρbulk, ρdryand ρashwere determined experimentally. A large variation was found in the mean Hounsfield units of the bone cores (HUcore) with a constant bias from ρCTto ρashof 42.5 mg/cm3. Computed tomography and ash densities were linearly correlated (R2= 0.55, p < 0.001). It was demonstrated that ρashprovided a good estimate of ρbulk(R2= 0.78, p < 0.001) and is a strong predictor of ρdry(R2= 0.99, p < 0.001). In addition, the ρCTwas linearly related to ρbulk(R2= 0.43, p < 0.001) and ρdry(R2= 0.56, p < 0.001). In conclusion, mineral density was an appropriate predictor of ρbulkand ρdry, and ρCTwas not a surrogate for ρash. There were linear relationships between ρCTand physical densities; however, following the experimental protocols of this study to determine ρCT, considerable scatter was present in the ρCTrelationships.
authors.affiliation: Department of Mechanical Engineering, University of Wisconsin-Madison, Madison, WI, USA Facultad de Ingeniería y Ciencias, Universidad Adolfo Ibáñez, Viña del Mar, Chile.
authors.forename: Juan F
authors.initials: JF
authors.lastname: Vivanco
authors.affiliation: Van Andel Research Institute, Grand Rapids, MI, USA.
authors.forename: Travis A
authors.initials: TA
authors.lastname: Burgers
authors.affiliation: Department of Mechanical Engineering, University of Wisconsin-Madison, Madison, WI, USA.
authors.forename: Sylvana
authors.initials: S
authors.lastname: García-Rodríguez
authors.affiliation: Department of Mechanical and Materials Engineering, Queen's University, Kingston, ON, Canada Human Mobility Research Centre, Kingston General Hospital, Queen's University, Kingston, ON, Canada.
authors.forename: Meghan
authors.initials: M
authors.lastname: Crookshank
authors.affiliation: Human Mobility Research Centre, Kingston General Hospital, Queen's University, Kingston, ON, Canada.
authors.forename: Manuela
authors.initials: M
authors.lastname: Kunz
authors.affiliation: Human Mobility Research Centre, Kingston General Hospital, Queen's University, Kingston, ON, Canada.
authors.forename: Norma J
authors.initials: NJ
authors.lastname: MacIntyre
authors.affiliation: Human Mobility Research Centre, Kingston General Hospital, Queen's University, Kingston, ON, Canada Department of Surgery, Queen's University, Kingston, ON, Canada.
authors.forename: Mark M
authors.initials: MM
authors.lastname: Harrison
authors.affiliation: Department of Mechanical and Materials Engineering, Queen's University, Kingston, ON, Canada Human Mobility Research Centre, Kingston General Hospital, Queen's University, Kingston, ON, Canada.
authors.forename: J Tim
authors.initials: JT
authors.lastname: Bryant
authors.affiliation: Department of Mechanical and Materials Engineering, Queen's University, Kingston, ON, Canada Human Mobility Research Centre, Kingston General Hospital, Queen's University, Kingston, ON, Canada.
authors.forename: Rick W
authors.initials: RW
authors.lastname: Sellens
authors.affiliation: Department of Mechanical Engineering, University of Wisconsin-Madison, Madison, WI, USA ploeg@engr.wisc.edu.
authors.forename: Heidi-Lynn
authors.initials: HL
authors.lastname: Ploeg
keywords: Computed tomography; X-ray attenuation; bone density; femoral head; trabecular bone