title: Measuring apparent trabecular structure with pQCT: a comparison with HR-pQCT.
abstract: We evaluated how comparable peripheral quantitative computed tomography (pQCT) measurements of cortical thickness, density, and apparent trabecular structure at the ultradistal tibia were with those measured with high-resolution pQCT (HR-pQCT). We also examined whether the accuracy of the pQCT-based trabecular and cortical measurements improved with reductions in slice thickness from the standard 2.2mm to 1.1 and 0.6mm. We immersed 15 dry tibia specimens in saline in a sealed cylinder and scanned 22.5mm from the distal tibia plateau using pQCT and HR-pQCT. pQCT underestimated cortical thickness by Stratec (CThStratec) and trabecular spacing (Tb.Sp) by 21.4% and 72.9%, whereas bone volume to total volume (BV/TV) and cortical density (CDen) were overestimated by 265.8% and 13.1%, respectively. Measurements of trabecular volumetric bone mineral density, trabecular area, total area, cortical thickness by custom software were comparable, but for CThStratec, Tb.Sp, BV/TV, and CDen, the differences between imaging devices varied with magnitude of the estimate. We recommend that researchers or clinicians interested in using pQCT to measure apparent trabecular structure or cortical thickness at the epiphyses, or in comparing findings from different devices, be aware of the differences between HR-pQCT and pQCT.
authors.affiliation: Department of Kinesiology, University of Waterloo, Waterloo, ON, Canada; Toronto Rehabilitation Institute-University Health Network, Lyndhurst Centre, Toronto, ON, Canada.
authors.forename: Deena
authors.initials: D
authors.lastname: Lala
authors.affiliation: Department of Medicine and Medical Imaging, University of Toronto, Toronto, ON, Canada; University Health Network, Toronto, ON, Canada.
authors.forename: Angela M
authors.initials: AM
authors.lastname: Cheung
authors.affiliation: Department of Kinesiology, University of Waterloo, Waterloo, ON, Canada; Toronto Rehabilitation Institute-University Health Network, Lyndhurst Centre, Toronto, ON, Canada.
authors.forename: Cheryl L
authors.initials: CL
authors.lastname: Lynch
authors.affiliation: Department of Civil Engineering, McMaster University, Hamilton, ON, Canada.
authors.forename: Dean
authors.initials: D
authors.lastname: Inglis
authors.affiliation: Department of Radiology, McMaster University, Hamilton, ON, Canada.
authors.forename: Chris
authors.initials: C
authors.lastname: Gordon
authors.affiliation: Department of Medicine and Medical Imaging, University of Toronto, Toronto, ON, Canada; University Health Network, Toronto, ON, Canada; Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada.
authors.forename: George
authors.initials: G
authors.lastname: Tomlinson
authors.affiliation: Department of Kinesiology, University of Waterloo, Waterloo, ON, Canada; Toronto Rehabilitation Institute-University Health Network, Lyndhurst Centre, Toronto, ON, Canada. Electronic address: lora.giangregorio@uwaterloo.ca.
authors.forename: Lora
authors.initials: L
authors.lastname: Giangregorio
mesh_terms: D019412:Anatomy, Cross-Sectional; D001837:Body Weights and Measures; D015519:Bone Density; D002102:Cadaver; D006801:Humans; D015203:Reproducibility of Results; D013977:Tibia / Q000000981:diagnostic imaging* / Q000473:pathology*; D014057:Tomography, X-Ray Computed
keywords: Accuracy; bone density; bone geometry; bone structure; peripheral quantitative computed tomography