Imaging

Dual-energy x-ray absorptiometry (DXA)

a man lays on a table with a bone density scan machine moving over his body Dual-energy X-ray absorptiometry is performed to assess whole-body, hip and spine bone mass, and body composition (including muscle and fat mass). A Norland ELITE and/or Hologic Horizon machine is used for scanning. Each participant undergoes one whole-body scan (scan time = 10 min), and single hip and spine scans (scan time = 3 min each). The collection of bone mass data takes a maximum of 20-25 minutes to complete which includes time to prepare and position the participant. The scans are performed with the participant lying on their backs on the padded table of the scanner while wearing thin clothing. Data collected from these assessments includes:

Whole-body bone mass, lean mass, fat mass
Hip bone mass and areal bone mineral density
Lumbar spine bone mass and areal bone mineral density

High resolution peripheral quantitative computed tomography (HR-pQCT)

HR-pQCT is performed using a Scanco Medical XtremeCT II machine. Scans are performed of the nondominant radius and tibia. Participants are seated with their lower leg or forearm supported in an air-cushioned splint in order to limit movement during the scan, and centered within the gantry of the HR-pQCT machine (see left image below). A scout scan is performed to enable tomographic scan localization, and 168 consecutive tomographic slices are taken at 4% and 30% proximal of bone length from the distal end of the respective bone (see right image below of distal tibia scan separated into cortical, subcortical [yellow] and trabecular compartments). Each participant has a total of 4 HR-pQCT scans (distal [4%] and diaphyseal [30%] tibia and radius), with each scan taking approximately two minutes to complete. The time to prepare and position the participant and perform the HR-pQCT assessments takes a maximum of 20 minutes.

Analyses include both cortical and trabecular bone. Measures acquired include:

Total bone area (Tt.Ar; mm2)
Cortical area (Ct.Ar; mm2),
Cortical thickness (Ct.Th; mm)
Cortical density (Ct.vBMD; mg/cm3)
Trabecular thickness (µm)
Trabecular separation (µm)
Trabecular number (N/mm),
Bone voume fraction (BV/TV; %)
Cortical porosity (Ct.Po; %)
Bone quantity measures (volumetric bone mineral density [mg/cm3] and bone mineral content [mg/mm]) are also recorded from the tomographic slices.

on the left, an man sits with his leg in a CT scan machine. On the right is a layered tomography image of his bone structure.

Related Publications

Warden SJ, Sventeckis AM, Surowiec RK, Fuchs RK. Enhanced Bone Size, Microarchitecture, and Strength in Female Runners with a History of Playing Multidirectional Sports. Med Sci Sports Exerc. 2022 Dec 1;54(12):2020-2030.

Warden SJ, Liu Z, Fuchs RK, van Rietbergen B, Moe SM. Reference data and calculators for second-generation HR-pQCT measures of the radius and tibia at anatomically standardized regions in White adults. Osteoporos Int. 2022 Apr;33(4):791-806.

Warden SJ, Wright CS, Fuchs RK. Bone Microarchitecture and Strength Adaptation to Physical Activity: A Within-Subject Controlled HRpQCT Study. Med Sci Sports Exerc. 2021 Jun 1;53(6):1179-1187.