:: CaMos Imaging Centre


DXA and Morphometric X-Ray Analysis

Morphometric analysis of Spinal Radiographs

All CaMos participants aged 50 years and older have lateral spinal radiographs taken of their lumbar and thoracic spines. The radiologist's report and the original X-ray are forwarded to Quebec city where the digitizing technician marks six points on each vertebral body, these points correspond to the four corners of the vertebral body, and the midpoints of the superior and inferior end plates. The points are used to define the anterior, posterior, and middle heights of each vertebra. The ratios of the vertebral heights to each other and to adjoining vertebrae are used to determine the presence or absence of vertebral deformity.

Quality control for DXA

An important aspect of any clinical study is to establish a thorough and effective quality control program to detect any changes in machine performance over the course of the study. Meticulous quality control records must be maintained to allow retrospective correction of data, if required, as a result of machine drift or to account for inter-site differences. A well-defined QC protocol will increase the statistical power of the study.

dxaThe Quality Assurance program developed for the CaMos study involves one morphometric phantom measured using the bone density (DXA) machine at each site at least once per week. The Bona Fide Spine Phantom is used in this study as a realistic phantom, more closely simulating body tissues, with bone mineral densities within the clinical range of interest. It is transported between the clinical sites once a year as an inter-site phantom.


Contact:

Marc Gendreau
Le centre Hospitalier Universitaire de Québec
Pavillon CHUL
2705 blvd Laurier, suite S-782
Québec, QC
G1V 4G2

Director : Dr. Jacques Brown

:: Participants

Men and women, aged 25 years and older, recruited from 1995 to 1997, residing within a 50 km radius of one of nine designated clinical centres, contacted at random by phone.

Youth cohort: men and women, aged 16-24 recruited from 2004-2006.


:: Data Collection

At baseline, year 3 (for participants 40-60), year 5 and year 10, a long questionnaire was administered to all consenting participants. A follow up mailed questionnaire was completed annually. Self reported fractures were confirmed by medical report or hospital discharge.

Bone density was measured using DXA (dual-energy X-ray absorptiometry) at the lumbar spine and hip, and ultrasound of the shin and wrist were taken.

Participants aged 50 years and older have had radiographs taken of the thoracic and lumbar spine. Blood, urine and DNA samples have been collected from participants in some centers at baseline, year 5 and year 10 follow-up.