Overview of µCT and pDXA Services

High-resolution micro-computed tomography (µCT) provides provides non-destructive, quantitative and qualitative assessment of trabecular and cortical bone microarchitecture. µCT is particularly useful for studies that utilize animal models to examine the effects of genetic manipulations, mechanical stimuli and/or pharmacological agents on skeletal characteristics. It is also useful for characterizing scaffolds used for tissue engineering applications. We are able to scan ex vivo samples that are up to 36 mm in diameter and 80 mm in length at resolutions down to 8 µm (µCT40, Scanco Medical AG). The µCT services are directed by Dr. Mary Bouxsein who is a leading expert in µCT analysis of bone. Guidelines for the use of µCT analysis of rodent bones were published by Dr. Bouxsein and colleagues (PDF). While we mainly µCT perform analysis of rodent specimens, we are able to work with clients to analyze the microstructure of many other types of specimens. As all scanning is performed on excised specimens, there is no need for additional IRB approvals. Specimens can be scanned in a variety of media (saline, formalin, ETOH), such that specimens can be used for subsequent histologic or other analyses.

µCT services that we can provide include:

• µCT scanning of ex vivo specimens up to 36 mm in diameter and 80 mm in length
• Trabecular and cortical bone micro-architecture analysis
• Osmium tetroxide staining for the analysis of marrow adiposity via µCT
• Custom scanning and analysis to measure client-defined parameters
• Preparation of 2D and 3D images and movies for publications and presentations(click here to see examples of the types of images that we can create)
• Expert consultation on study design, as well as interpretation of results

**We also offer in vivo peripheral dual-energy x-ray absorptiometry (pDXA, PIXImus II) for the measurement of areal bone mineral density (BMD), bone mineral content (BMC) and body composition in mice. Measurements in mice require less than five minutes under anesthesia and are ideal for longitudinal studies. IRB approval is generally required, as these measurements are performed in vivo.We provide training on the use of the PIXImus II scanner so that users can perform the measurements on their animals.

Equipment

• µCT measurements are performed using a µCT40 scanner (SCANCO Medical AG)
• DEXA measurements are performed using a PIXImus II densitometer (GE Medical Systems)

Typical µCT measurements:

Most of the analysis that we perform is on mouse femurs. Our typical mouse femur analysis involves a scan of the distal metaphysis to analyze trabecular architecture and a scan at the mid-diaphysis to measure cortical bone architecture and mineral density. Other bones that we regularly analyze are the tibia and the lumbar vertebral body. Both trabecular and cortical bone can be performed in the tibia, but typically only trabecular bone is analyzed in the vertebral body. In addition to mouse bones, we are also able to analyze specimens from other species as long as they fit in a cylindrical specimen holder that is 36 mm in diameter and 80mm tall.