Bone mineral density assessment using iterative reconstruction compared with quantitative computed tomography as the standard of reference

Cortex or cancellous-which is early for the decrease of bone content for vertebral body in health?

OBJECTIVE

To obtain the cortex and cancellous parameter of the vertebral bone of healthy subjects using QCT. To explore which is earlier or faster for bone loss with age.

MATERIALS AND METHODS

733 physical examiners underwent chest low-dose CT examination were recruited, from April 1, 2021 to October 1, 2021. QCT sequence was used to obtain the bone mineral density of T12-L2 vertebral body without additional radiation. The mass and area of vertebral cortex and cancellous at the central level of L2 vertebral body were measured. The age -related characteristics of vertebral cortex and cancellous between male and female was analyzed and compared.

RESULTS

The vBMD of T12-L2 vertebral body decreased with age. Significant differences were found in volumetric bone mineral density (vBMD) of T12-L2 vertebral body. For female, significant differences were found in bone content involving cortical mass, cancellous mass, cortical area, cancellous area, cortical mass/cancellous mass and cortical area/cancellous area in different age groups, respectively. The cortical mass decreased with age in female. The cancellous mass of female increased and then decreased with peak at 31-40 y. The cortical area of female decreased gradually before 71 y. The cancellous area of female increased and then decreased with peak at 51-60 y. The values of mass ratio and area ratio in female showed a slowly downward trend with age. Significant differences of bone content between non-menopausal and menopausal women were found except the cancellous mass. For male, no significant differences were found in all parameters of bone content.

CONCLUSION

The changes of vertebral BMD, bone content of cortex and cancellous have different characteristics in different age. The change of cortex in female maybe earlier and faster than that of cancellous, especially in menopausal women.

The applicability of trabecular bone score for osteoporosis diagnosis in ankylosing spondylitis

Ankylosing spondylitis (AS) patients have a high risk of osteoporotic fractures. The aim of this study was to evaluate the usefulness of trabecular bone score (TBS) in assessing fracture risk in patients with AS. 67 patients meeting the ASAS classification criteria were enrolled in the study. Fracture risk for each patient was assessed based on a lumbar spine exam encompassing bone mineral density (BMD), and TBS through a dual-energy X-ray absorptiometry (DXA) exam. In addition, each patient had an X-ray taken of their lumbar and thoracic spine to determine the presence of syndesmophytes and bony bridges, as well as spinous process and vertebral body fractures. Moreover, each patient's medical history was analyzed for other osteoporotic fractures. A major osteoporosis fracture (MOF) was found in 11 (16%) patients in total, of which 7 (10%) were vertebral body fractures. The mean TBS in patients with MOF and no MOF were, respectively, 1.12 and 1.29 (p < 0.001). No significant differences were found in BMD scores between the two groups. Syndesmophytes and bony bridges occurred more frequently in patients with MOF (p = 0.02). Age of 50 or more (RR = 9.86, p = 0.002), TBS score ≤ 1.31 (RR = 2.07, p < 0.0001), and presence of syndesmophytes and bony bridges (RR = 2.14, p = 0.04) were considered a relative risk (RR) increasing factors. TBS is a markedly more sensitive method of identifying patients with a high fracture risk compared to BMD measurement in a DXA exam in patients with AS.

Methods for bone quality assessment in human bone tissue: a systematic review

Background

For biomechanical investigations on bone or bone implants, bone quality represents an important potential bias. Several techniques for assessing bone quality have been described in the literature. This study aims to systematically summarize the methods currently available for assessing bone quality in human bone tissue, and to discuss the advantages and limitations of these techniques.

Methods

A systematic review of the literature was carried out by searching the PubMed and Web of Science databases from January 2000 to April 2021. References will be screened and evaluated for eligibility by two independent reviewers as per PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Studies must apply to bone quality assessment with imaging techniques, mechanical testing modalities, and compositional characterization. The terms used for the systematic search were: “(bone quality”. Ti,ab.) AND “(human bone specimens)”.

Results

The systematic review identified 502 relevant articles in total. Sixty-eight articles met the inclusion criteria. Among them, forty-seven articles investigated several imaging modalities, including radiography, dual-energy X-ray absorptiometry (DEXA), CT-based techniques, and MRI-based methods. Nineteen articles dealt with mechanical testing approaches, including traditional testing modalities and novel indentation techniques. Nine articles reported the correlation between bone quality and compositional characterization, such as degree of bone mineralization (DBM) and organic composition. A total of 2898 human cadaveric bone specimens were included.

Conclusions

Advanced techniques are playing an increasingly important role due to their multiple advantages, focusing on the assessment of bone morphology and microarchitecture. Non-invasive imaging modalities and mechanical testing techniques, as well as the assessment of bone composition, need to complement each other to provide comprehensive and ideal information on the bone quality of human bone specimens.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-022-03041-4.

Sources of error in bone mineral density estimates from quantitative CT

Bone mineral density (BMD) estimates from quantitative computed tomography (QCT) have proven useful for opportunistic screening of osteoporosis, treatment monitoring, and bone strength measurement. These estimates are subject to bias and variance from a variety of sources related to the imaging equipment, methods applied in the estimation procedure, and the patients themselves. In this article, we review the literature to describe the sources and sizes of error in spine and hip BMD estimates from single-energy QCT that can result from factors related to the scanner, imaging techniques, imaging subject, calibration phantom, and calibration approach. We also describe the baseline variance that can be expected based on repeatability and reproducibility studies. Though reproducible BMD estimates may be achievable with QCT, a thorough understanding of the potential sources of error and their size relative to the diagnostic task is essential to their appropriate and meaningful interpretation.