Comparison between quantitative calcaneal and tibial ultrasound in a Dutch Caucasian pediatric and adolescent population

Reproducibility of a peripheral quantitative computed tomography scan protocol to measure the material properties of the second metatarsal

Background

Peripheral quantitative computed tomography (pQCT) is an established technology that allows for the measurement of the material properties of bone. Alterations to bone architecture are associated with an increased risk of fracture. Further pQCT research is necessary to identify regions of interest that are prone to fracture risk in people with chronic diseases. The second metatarsal is a common site for the development of insufficiency fractures, and as such the aim of this study was to assess the reproducibility of a novel scanning protocol of the second metatarsal using pQCT.

Methods

Eleven embalmed cadaveric leg specimens were scanned six times; three times with and without repositioning. Each foot was positioned on a custom-designed acrylic foot plate to permit unimpeded scans of the region of interest. Sixty-six scans were obtained at 15% (distal) and 50% (mid shaft) of the second metatarsal. Voxel size and scan speed were reduced to 0.40 mm and 25 mm.sec^-1. The reference line was positioned at the most distal portion of the 2^nd metatarsal. Repeated measurements of six key variables related to bone properties were subject to reproducibility testing. Data were log transformed and reproducibility of scans were assessed using intraclass correlation coefficients (ICC) and coefficients of variation (CV%).

Results

Reproducibility of the measurements without repositioning were estimated as: trabecular area (ICC 0.95; CV% 2.4), trabecular density (ICC 0.98; CV% 3.0), Strength Strain Index (SSI) - distal (ICC 0.99; CV% 5.6), cortical area (ICC 1.0; CV% 1.5), cortical density (ICC 0.99; CV% 0.1), SSI – mid shaft (ICC 1.0; CV% 2.4). Reproducibility of the measurements after repositioning were estimated as: trabecular area (ICC 0.96; CV% 2.4), trabecular density (ICC 0.98; CV% 2.8), SSI - distal (ICC 1.0; CV% 3.5), cortical area (ICC 0.99; CV%2.4), cortical density (ICC 0.98; CV% 0.8), SSI – mid shaft (ICC 0.99; CV% 3.2).

Conclusions

The scanning protocol generated excellent reproducibility for key bone properties measured at the distal and mid-shaft regions of the 2^nd metatarsal. This protocol extends the capabilities of pQCT to evaluate bone quality in people who may be at an increased risk of metatarsal insufficiency fractures.

The bare bones of race

In this paper I examine claims of racial difference in bone density and find that the use and definitions of race in medicine lack a theoretical foundation. My central argument is that the social produces the biological in a system of constant feedback between body and social experience. By providing a different angle of vision on claimed racial differences I hope to move the conversation away from an ultimately futile discussion of nature versus nurture, where time is held constant and place seen as irrelevant, and begin to build a new paradigm for examining the contributions of geographic ancestry, individual lifecycle experience, race, and gender to varied patterns of health and disease.

Quantitative ultrasound methods to assess bone mineral status in children: technical characteristics, performance, and clinical application

Measurement of bone mineral status may be a useful tool in identifying the children who could be exposed to an increased risk of osteoporosis in adulthood. Dual energy x-ray absorptiometry and peripheral quantitative computed tomography may be used to this purpose, but the exposure to ionizing radiation is a limiting factor for preventive studies in large populations of children. In the last years, quantitative ultrasound (QUS) methods have been developed to assess bone mineral status in some peripheral skeletal sites such as calcaneus, phalanges of the hand, and tibia. QUS techniques are safe, easy to use, radiation-free, and devices are portable, so that they are particularly indicated to assess bone mineral status in children. This review will concentrate on the main methodological principles of ultrasounds and the QUS variables derived from their application to bone tissue, technical differences and performance of QUS methods, factors influencing QUS measurements, normative data and results obtained in children with disturbances of growth or affected by disorders of bone and mineral metabolism, including the assessment of fracture risk, and comparison among QUS, dual energy x-ray absorptiometry, and peripheral quantitative computed tomography methods.

Tibial cortical bone properties of preadolescents and their mothers in an urban area associated with lifestyle: a longitudinal study

AIM

A 12-mo follow-up observation was performed to evaluate the tibial cortical bone properties of preadolescent children and their mothers in a densely populated area of Tokyo in association with their lifestyle in the context of healthy bone development of urban children.

METHODS

Fifty-four volunteer mother-child pairs were examined twice: once in the 1st grade of elementary school and once in the following year. Tibial cortical speed of sound (TCSOS) was measured by non-invasive quantitative ultrasonometry. Nutritional intake and recreational activity were examined using a structured interview.

RESULTS

TCSOS of the children showed a positive association with intake of vegetables, including potatoes and fruits (1st grade, r = 0.31, p < 0.05; 2nd grade, r = 0.33, p < 0.05), and inversely correlated with indoor recreational activities (1st grade, r = -0.28, p < 0.05). The z-score of TCSOS of the mothers was correlated with intake of milk, dairy products and eggs (r = 0.35, p < 0.001). However, there were no statistically significant correlations in TCSOS between children and their mothers.

CONCLUSION

A 1-y longitudinal study in urban children indicated the effects of specific types of food intake and recreational activities of children on tibial bone properties.

Monitoring bone mass, bone density and bone geometry in children and adolescents

The number of articles dealing with pediatric bone mass measurements has flourished during the last decade. The reasons include the awareness that bone gained early in life is an important factor in determining the risk of osteoporosis later in life and the expanding number of pediatric diseases associated with low bone mass. Dual-energy x-ray absorptiometry is the most common method for measurement of bone mineral content or bone mineral density. Quantitative computed tomography and quantitative ultrasound are the emerging techniques which offer the possibility of measuring bone mineral content, bone mineral density and quantitative ultrasound parameters that are unique to children and will be discussed in this review. The interpretation of bone mass measurements is also often difficult in growing individuals and the peculiar aspects pertaining to this problem are examined.

Speed of sound: relation to geometric characteristics of bone in children, adolescents, and adults

OBJECTIVES

To investigate the relation between volumetric bone mineral density (vBMD) and speed of sound (SOS).

STUDY DESIGN

Total and trabecular vBMD were measured by peripheral quantitative computed tomography at the forearm in a population of 216 individuals of a pediatric outpatient clinic. Moreover, SOS was measured by a quantitative ultrasound device (QUS) at the thumb, patella, and os calcis.

RESULTS

Linear regression analysis revealed that the prediction of SOS by vBMD is relatively weak (R2 < 0.1). Moreover, body height and measures of bone size have a stronger influence on SOS than vBMD. The influence of bone size on SOS also depends on the location of measurement (highest prediction of SOS by body height at patella with R2 = 0.56). Anthropometric characteristics have a stronger influence on SOS than measures of bone mineral density at the thumb and patella in comparison to os calcis (body height predicts SOS at os calcis, with R2 = 0.03). Conclusions QUS is not a suitable method to assess bone density. If QUS is applied for the assessment of bone development and of bone fracture risk, the measurement should be performed with consideration of anthropometric measurements.

The use of quantitative ultrasound in assessing bone status in newborn preterm infants

OBJECTIVE

Quantitative ultrasound is increasingly used to assess bone status in adults and children; however, few studies have been carried out in neonates. Our objective was to determine if tibial bone speed of sound (SOS) correlates with gestational age and birth anthropometrics, and if bone SOS is related to maternal factors.

STUDY DESIGN

We prospectively studied 95 preterm infants to assess factors related to bone status as measured by quantitative ultrasound.

RESULTS

We found significant (p< or =0.001) positive correlations between SOS and gestational age, birth weight, length, head circumference and tibial length. There was no significant relationship between SOS and prenatal steroid use, gestational diabetes, pre-eclampsia, race or parity.

CONCLUSIONS

Quantitative ultrasound is an easy to use and inexpensive tool for assessing bone status in preterm neonates. Tibial SOS correlated with gestational age and birth anthropometrics, and was not related by few maternal factors.