(1) Bone Quality Research Studies
This section of the site is dedicated to brief synopses of our ongoing research projects
To promote academic excellence by pursuing innovative research ideas, conducting high quality research studies, fostering multidisciplinary collaborations and facilitating the education and success of students and young investigators.
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Bone density is currently used for diagnosing patients with osteoporosis but only explains less than 20% of those who fracture. Bone structure information can supplement bone density in estimating bone strength of individuals. This study compares how peripheral quantitative computed tomography (pQCT) and high-resolution (hr) pQCT can provide useful bone structure information that can discriminate individuals with and without fractures. It will also evaluate how bone structure information obtained from the two imaging modalities can supplement information on bone density for predicting those who fracture.
This is a head-to-head technology comparison five-year prospective cohort study examining Canadian men and women across six major municipalities. The study leverages on participants of the Canadian Multicentre Osteoporosis Study (CaMos, www.camos.org) who will complete pQCT, hr-pQCT, DXA scans as well as physical function (grip strength, timed ‘up-and-go' test, walking speed) tests and medication use questionnaires (vitamin D, Ca, antiresorptives, anabolics, hormone therapy). Prevalent fractures will be determined from the CaMos database over the last 15 years and incident adjudicated fractures will be collected annually by questionnaire.
Multi-modality comparison, validation and cross-calibration of bone architecture: 1T pMRI, pQCT, hr-pQCT
Bone structure information can be obtained from magnetic resonance imaging (MRI), peripheral quantitative computed tomography (pQCT) and high resolution (hr)-pQCT. One can appreciate that the differences between CT and MRI technologies may render structural information measured from bones to be different- CT technology is based on linear attenuation of X-ray particles and provides a density-scaled image of anatomy; MR technology is based on proton density of materials and can be affected by large differences in susceptibility of materials to magnetic fields. Since a number of studies have examined these three imaging techniques, it is worth highlighting their strengths and limitations by assessing their construct validity, and their short and long term reproducibilities.
A subset of the CaMos participants at the Hamilton Centre completed scans on all three modalities within three months. The same site of the wrist was examined on each imaging modality allowing comparison of structural information across techniques. Each scan was repeated during the same visit with complete removal from the scanner. Scans were performed at the same location again one year later. Short term and long term least significant change was measured for each modality. Both pMRI and pQCT structural parameters were correlated with those measured on hr-pQCT using a linear regression analysis. The study provided slope and intercept values that provided an indication of the systematic difference between imaging techniques. In addition, the precision error percent for short and long-term repeated measurements were identified for each method.
Bone microstructural phantom design - MR and CT compatible
Bone structure information can be obtained from magnetic resonance imaging (MRI) and from quantitative computed tomography (QCT) technologies. While MRI focuses on proton density, QCT hinges upon the linear attenuation of X-ray particles for true density measurement. Currently, there is no method for calibrating MRI and QCT measurements of bone structure for quality control purposes. The quality of geometry measured on the macroscopic scale - in the order of > 5 mm2 - can be monitored using morphometric phantoms with calibrated densities. However, trabecular bone ranges between 100-250 µm and therefore its accuracy cannot be assessed using these large scale phantoms.
We are currently designing bone microstructural phantoms that are compatible with QCT and MRI technologies - namely providing sufficient density in the bone and sufficient proton signal in the surrounding fluid and muscle mimic. This phantom could be used in the future for calibrating and cross-calibrating imaging modalities in multi-centre studies such as the CaMs Bone Quality Study.