Measurements of bone mineral density in the lumbar spine and proximal femur using lunar prodigy and the new pencil-beam dual-energy X-ray absorptiometry

Natural changes of traumatic vertebral compression fractures during the first 6 months in patients visiting for disability certificates: A retrospective observational study

To identify the natural changes of traumatic vertebral compression fractures during the first six months in patients visiting for disability certificates after conservative treatment.Data of patients who visited the rehabilitation medicine department of a university hospital for disability certificates concerning traumatic vertebral compression fractures from 2015 to 2018 were reviewed. Those who visited 180 to 210 days after injuries were included, and those who received invasive procedures for compression fractures were excluded. The anterior and posterior heights, local kyphotic angle of compression fractures, and upper and lower vertebrae on initial and follow-up images were measured and compared. Compression ratio was calculated by vertebral body compression ratio and anterior vertebral body compression percentage. Thoracic and lumbar traumatic fractures were also compared.Among 110 patients, 61 patients met the criteria. After six months, the anterior height of compression fractures decreased more than 4 mm, which implies the development of new compression fractures. The compression ratio and local kyphotic angle increased significantly without affecting the upper and lower vertebrae. Thoracic and lumbar compression fractures showed similar changes.Traumatic vertebral compression fractures change significantly during the first six months. This study could warrant 6 months of waiting for issuance of disability certificates for patients with traumatic vertebral compression fractures.

A cross-calibration study of the GE-Lunar iDXA and prodigy for the assessment of lumbar spine and total hip bone parameters via three statistical methods

This study assessed agreement between the GE Lunar iDXA and Prodigy densitometers for bone measurements and used 3 statistical methods to derive cross-calibration equations: linear regression, the Deming method, and multivariate analysis. Compatibility of machines for the measurements of bone mineral density, bone mineral content, and bone area also was explored. Eighty-five adults, age: 45.5 (SD 12.8) years; body mass index: 25.6 (SD 3.7) kg.m(-2) were measured once at the lumbar spine: L1-L4 and total hip on each densitometer, within 24 hours. Both linear regression and Deming analysis indicated that cross-calibration equations were required at the lumbar spine and total hip but not at the femoral neck. Multivariate analysis identified femur thickness and femur percent fat as predictive variables at the femoral neck and total hip. Bland Altman analysis (Prodigy-iDXA) indicated significant positive bone mineral density bias at the lumbar spine and femoral neck. Significant bone mineral content biases were observed at all 3 sites and bone area biases at both hip sites. These initial results suggest there are small significant differences in the bone parameters and that all 3 bone parameters should be evaluated when comparing densitometers, especially when there are differences in pixel size between the densitometers.