Musculoskeletal and Body Composition Imaging Core

Overview of Services

Musculoskeletal and Body Composition Imaging Core
Musculoskeletal (MSK) disorders are common, with three quarters of adults aged 65 and over seeking medical care for such a condition at some time during their life. These diseases encompass a wide spectrum of conditions, most commonly osteoporosis, parathyroid disorders, osteoarthritis and autoimmune diseases. In addition, many different illnesses and medications, such as kidney disease and glucocorticoids, have important secondary effects on the skeleton and on body composition. The Musculoskeletal and Body Composition Imaging Core offers both state-of-the art established and innovative technologies for imaging bone density, bone microarchitecture and strength, as well as body composition and joint imaging. We provide a unified and centralized resource with first-rate technical expertise in image acquisition and image analysis of bone, body composition and joint imaging for investigators from multiple disciplines who study MSK disorders and other conditions and therapies that impact the MSK system. We are also highly experienced with multicenter imaging studies and will work with coordinating centers within and outside Columbia to acquire data for cross-sectional and longitudinal studies according to study-specific parameters, including phantom circulation across study sites. Available technologies include:

• Dual energy x-ray absorptiometry (DXA; Hologic technology)
DXA is the gold-standard technology for measurement of bone mineral density and is a common variable of interest for epidemiologic studies and a common efficacy and/or safety endpoint for clinical trials of bone-active agents.

The following tests are available:                
o Areal bone mineral density (BMD)
- Total body
- Lumbar spine
- Hip
- Forearm
o Vertebral fracture assessment (VFA) to screen for vertebral fractures
o Trabecular bone score (TBS), a textural analysis of spine BMD images that predicts incident fractures
o Single energy femur scanning, useful for studies of atypical femur fractures
o Body composition assessment

• High-resolution peripheral quantitative computed tomography (HR-pQCT; Xtreme CT2)
DXA does not provide information about bone microstructure, another important determinant of bone strength. Xtreme CT technology permits in vivo assessment of true volumetric BMD and bone microstructure at the distal radius and tibia. After scan acquisition, standard and novel image processing techniques can be applied to characterize bone quality and strength. HR-pQCT has been applied to understand the impact of race, gender/ethnicity, diverse diseases and medications on bone microarchitecture and strength. Cross-sectional studies have shown that HR-pQCT is capable of discriminating fracture status independent of areal BMD by DXA. HR-pQCT parameters and failure load – an index of bone strength – have also been shown to improve fracture prediction. The second generation HR-pQCT scanner, Xtreme CT2, acquired in 2015, has a resolution of 62 microns and is capable of scanning the distal radius and distal tibia. New research directions include scanning the knee in patients with osteoarthritis, and the wrist, elbow, and metacarpophalangeal joints in patients with inflammatory arthritides (rheumatoid arthritis, psoriatic arthritis, and systemic lupus erythematosus).
The following areas can be imaged:
o Distal radius
o Distal tibia
o Mid tibia
o Knee
o Wrist
o Elbow
o Metacarpophalangeal joints

• Advanced HR-pQCT analyses
HR-pQCT datasets can be computationally modeled by micro-finite element analysis (µFEA), to integrate all the macro- and microstructural data into a single estimate of bone stiffness, a surrogate measure of bone strength. In addition to µFEA, advanced image analyses can be applied to HR-pQCT datasets; in collaboration with Dr. Edward Guo, Chair of Biomedical Engineering, individual trabecular segmentation (ITS) can characterize trabecular morphology as either plate-like or rod like. The plate-like morphology has been shown to be associated with greater bone strength.

Available measures include:
o Finite element analysis, for bone stiffness, failure load
o Individual trabecular segmentation (ITS

• Central quantitative computed tomography (cQCT)
Central QCT has several advantages for measurement of BMD. It measures true volumetric BMD of the lumbar spine (L1, L2) and hip (proximal femur). Unlike DXA, cQCT is not affected by bone size, abdominal obesity, osteoarthritis or vascular calcifications. At the hip, the resolution of cQCT is sufficiently high to distinguish between cortical and trabecular bone. As with HR-pQCT, CT datasets can be computationally modeled by µFEA, to integrate all the macro- and microstructural data into a single estimate of bone stiffness and failure load, a surrogate measure of bone strength. Central QCT is increasingly used in observational studies and to evaluate longitudinal changes in volumetric BMD and strength in response to drug treatment.

Unlike DXA and HR-pQCT scans, central QCT scans must be acquired in the Department of Radiology. The Musculoskeletal and Body Composition Imaging Core will provide access to the special bone phantoms required during the image acquisition in Radiology and consultation regarding the specific images to be acquired and appropriate timing of scans in relation to the research question(s) to be addressed. The following areas can be imaged:
o Lumbar spine L1, L2
o Proximal femur

Once acquired, the cQCT scans can be analyzed in the Imaging Core with dedicated software. The following analyses are available for the spine and hip.
o Total volumetric BMD
o Compartmental (trabecular and cortical) volumetric BMD.
o Finite element analysis, for bone stiffness, failure load (in collaboration with Dr. Edward Guo, Chair of Biomedical Engineering)

Leadership

Location and hours of operation

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