The potential of digital X-ray radiogrammetry (DXR) in the assessment of osteopenia in children with chronic inflammatory bowel disease

Osteoporosis in children and adolescents: when to suspect and how to diagnose it

Early recognition of osteoporosis in children and adolescents is important in order to establish an appropriate diagnosis of the underlying condition and to initiate treatment if necessary. In this review, we present the diagnostic work-up, and its pitfalls, of pediatric patients suspected of osteoporosis including a careful collection of the medical and personal history, a complete physical examination, biochemical data, molecular genetics, and imaging techniques. The most recent and relevant literature has been reviewed to offer a broad overview on the topic. Genetic and acquired pediatric bone disorders are relatively common and cause substantial morbidity. In recent years, there has been significant progress in the understanding of the genetic and molecular mechanistic basis of bone fragility and in the identification of acquired causes of osteoporosis in children. Specifically, drugs that can negatively impact bone health (e.g. steroids) and immobilization related to acute and chronic diseases (e.g. Duchenne muscular dystrophy) represent major risk factors for the development of secondary osteoporosis and therefore an indication to screen for bone mineral density and vertebral fractures. Long-term studies in children chronically treated with steroids have resulted in the development of systematic approaches to diagnose and manage pediatric osteoporosis.

CONCLUSIONS

Osteoporosis in children requires consultation with and/or referral to a pediatric bone specialist. This is particularly relevant since children possess the unique ability for spontaneous and medication-assisted recovery, including reshaping of vertebral fractures. As such, pediatricians have an opportunity to improve bone mass accrual and musculoskeletal health in osteoporotic children.

WHAT IS KNOWN

• Both genetic and acquired pediatric disorders can compromise bone health and predispose to fractures early in life. • The identification of children at risk of osteoporosis is essential to make a timely diagnosis and start the treatment, if necessary.

WHAT IS NEW

• Pediatricians have an opportunity to improve bone mass accrual and musculoskeletal health in osteoporotic children and children at risk of osteoporosis. • We offer an extensive but concise overview about the risk factors for osteoporosis and the diagnostic work-up (and its pitfalls) of pediatric patients suspected of osteoporosis.

"Which skeletal imaging modality is best for assessing bone health in children and young adults compared to DXA? A systematic review and meta-analysis"

BACKGROUND

Skeletal imaging techniques have become clinically valuable methods for measuring and assessing bone mineral density in children and young people. Dual-energy X-ray absorptiometry (DXA) is the current reference standard for evaluating bone density, as recommended by the International Society for Clinical Densitometry (ISCD). Various bone imaging modalities, such as quantitative ultrasound (QUS), peripheral quantitative computed tomography (pQCT), high-resolution peripheral quantitative computed tomography (HR-pQCT), magnetic resonance imaging (MRI), and digital X-ray radiogrammetry (DXR) have been developed to further quantify bone health in children and adults. The purpose of this review, with meta-analysis, was to systematically research the literature to compare the various imaging methods and identify the best modality for assessing bone status in healthy papulations and children and young people with chronic disease (up to 18 years).

METHODS

A systematic computerized search of Medline, PubMed, and Web of Science databases was conducted to identify English-only studies published between 1st January 1990 and 1st December 2019. In this review, clinical studies comparing imaging modalities with DXA were chosen according to the inclusion criteria. The risk of bias and quality of articles was assessed using the Quality Assessment Tool for Diagnostic Accuracy Studies (QUADAS-2). The meta-analysis to estimate the overall correlation was performed using a Fisher Z transformation of the correlation coefficient. Additionally, the diagnostic accuracy measures of different imaging methods compared with DXA were calculated.

RESULTS

The initial search strategy identified 13,412 papers, 29 of which matched the inclusion and exclusion criteria. Of these, twenty-two papers were included in the meta-analysis. DXA was compared to QUS in 17 papers, to DXR in 7 and to pQCT in 4 papers. A single paper compared DXA, DXR, and pQCT. The meta-analysis demonstrated that the strongest correlation was between DXR and DXA, with a coefficient of 0.71 [95%CI: 0.43; 1.00, p-value < 0.001], while the correlation coefficients between QUS and DXA, and pQCT and DXA were 0.57 [95%CI: 0.25; 0.90, p-value < 0.001] and 0.57 [95%CI: 0.46; 0.67, p-value < 0.001], respectively. The overall sensitivity and specificity were statistically significant 0.71 and 0.80, respectively.

CONCLUSION

No current imaging modality provides a full evaluation of bone health in children and young adults, with each method having some limitations. Compared to QUS and pQCT, DXR achieved the strongest positive relationship with DXA. DXR should be further evaluated as a reliable method for assessing bone health and as a predictor of fractures in children and young people.

Bone Health Index and bone turnover in pediatric patients with type 1 diabetes mellitus and poor metabolic control

BACKGROUND

There is a need for a non-invasive, affordable, and reliable method for bone health screening in pediatric patients at risk.

OBJECTIVE

To assess Bone Health Index (BHI) in pediatric patients with type 1 diabetes (T1D) and its relation to bone metabolism, age at onset, duration, control, and insulin dose.

SUBJECTS AND METHODS

Left-hand radiographs were obtained from 65 patients with T1D, mean age 11.23 ± 3.89 years, mean disease duration 5.23 ± 3.76 years and mean glycosylated hemoglobin (HbA1c)-83 mmol/mol (9.7%). Blood and 24 hours urine samples were collected for bone and mineral metabolism assessment. BoneXpert was used to determine BHI, Bone Health Index standard deviation score (BHI SDS), and bone age.

RESULTS

Mean BHI SDS was -1.15 ± 1.19 (n = 54). In 20.37% (n = 11) BHI SDS was < -2SD with mean value -2.82 ± 0. 69, P < .001. These patients had lower levels of beta cross laps (0.77  ± 0.33 ng/mL vs 1.17 ± 0.47 ng/mL), osteocalcin (47.20 ± 14.07 ng/mL vs 75.91 ± 32.08 ng/mL), serum magnesium (0.79 ± 0.05 mmol/L vs 0.83 ± 0.06 mmol/L) and phosphorus (1.48 ± 0.29 mmol/L vs 1.71 ± 0.28 mmol/L) but higher ionized calcium (1.29 ± 0.04 mmol/L vs 1.26 ± 0.05 mmol/L), P < .05, compared to patients with BHI SDS in the normal range. We found a positive correlation between BHI SDS and age at manifestation (r = 0.307, P = 0.024) and a negative one with disease duration (r = -0.284, P = .038). No correlations were found with HbA1c, insulin dose, height, weight, BMI.

CONCLUSIONS

To the best of our knowledge, this is the first study to assess bone health in pediatric patients with T1D using BHI. We found significantly decreased cortical bone density and bone turnover in 20.37%. Earlier age at onset and diabetes duration may have a negative impact on cortical bone density in patients with poor control. Longitudinal studies are needed to follow changes or to assess future interventions.

Can digital X-ray radiogrammetry be an alternative for dual-energy X-ray absorptiometry in the diagnosis of secondary low bone quality in children?

Bone quality in children is generally measured with dual-energy X-ray absorptiometry (DXA). Digital X-ray radiogrammetry (DXR) uses BoneXpert to measure cortical bone quality on hand radiographs. This prospective study compared DXR and DXA results in children with high probability of secondary low bone quality, defined as DXA of the lumbar spine (DXA_LS) Z-score ≤ - 2.0. One hundred one children underwent both DXA and DXR assessment. DXA_LSZ-scores were also adjusted for bone age. DXR Z-scores were compared with both DXA_LSZ-scores, using Pearson correlations, Bland-Altman analysis, and sensitivity-specificity analysis. Mean bone age, DXR, and both DXA Z-scores were significantly impaired. Pearson correlation coefficients were significant between DXR Z-scores and both DXA_LSZ-scores 0.507-0.564 (p < 0.001). Bland-Altman analysis showed a mean difference of 0.05-0.48 between DXR and both DXA Z-scores and showed more than 90% similarity for both DXA_LSZ-scores ≤ - 2.0. DXR had a sensitivity of 67-71% and specificity of 77-83% compared to both DXA_LSZ-scores.Conclusion: DXR correlates well with as well DXA_LS as bone age-adjusted DXA_LSZ-scores and shows good agreement with as well DXA_LS as bone age-adjusted DXA_LSZ-scores ≤ - 2.0. DXR shows best results when compared with DXA_LSZ-scores. What is Known: • Digital X-ray radiogrammetry (DXR) may correlate well with dual-energy X-ray absorptiometry (DXA) in pediatric, adolescent, and adult patients. • DXR is a feasible method for assessment of bone quality in children. What is New: • This is the first prospective study in children with suspected secondary low bone quality that illustrates correlation between DXR and bone age-adjusted DXA Z-scores and that shows good agreement between DXR and DXA as bone age-adjusted DXA Z-scores ≤ -2.0. • Our results suggest DXR to be a good alternative for DXA for determining low bone quality.

Reference values for digital X-ray radiogrammetry parameters in children and adolescents in comparison to estimates in patients with distal radius fractures

The first objective of this study was to determine normative digital X-ray radiogrammetry (DXR) values, based on original digital images, in a pediatric population (aged 6-18 years). The second aim was to compare these reference data with patients suffering from distal radius fractures, whereas both cohorts originated from the same geographical region and were evaluated using the same technical parameters as well as inclusion and exclusion criteria. DXR-BMD and DXR-MCI of the metacarpal bones II-IV were assessed on standardized digital hand radiographs, without printing or scanning procedures. DXR parameters were estimated separately by gender and among six age groups; values in the fracture group were compared to age- and gender-matched normative data using Student's t tests and Z scores. In the reference cohort (150 boys, 138 girls), gender differences were found in bone mineral density (DXR-BMD), with higher values for girls from 11 to 14 years and for boys from 15 to 18 years (p < 0.05). Girls had higher normative metacarpal index (DXR-MCI) values than boys, with significant differences at 11-14 years (p < 0.05). In the case-control investigation, the fracture group (95 boys, 69 girls) presented lower DXR-BMD at 15-18 years in boys and 13-16 years in girls vs. the reference cohort (p < 0.05); DXR-MCI was lower at 11-18 years in boys and 11-16 years in girls (p < 0.05). Mean Z scores in the fracture group for DXR-BMD were -0.42 (boys) and -0.46 (girls), and for DXR-MCI were -0.51 (boys) and -0.53 (girls). These findings indicate that the fully digital DXR technique can be accurately applied in pediatric populations ≥ 6 years of age. The lower DXR-BMD and DXR-MCI values in the fracture group suggest promising early identification of individuals with increased fracture risk, without the need for additional radiation exposure, enabling the initiation of prevention strategies to possibly reduce the incidence of osteoporosis later in life.

Automated determination of bone age and bone mineral density in patients with juvenile idiopathic arthritis: a feasibility study

Introduction

Chronic inflammation combined with glucocorticoid treatment and immobilization puts juvenile idiopathic arthritis (JIA) patients at risk of impaired growth and reduced bone mineral density (BMD). Conventional methods for evaluating bone age and BMD are time-consuming or come with additional costs and radiation exposure. In addition, an automated measurement of bone age and BMD is likely to be more consistent than visual evaluation. In this study, we aimed to evaluate the feasibility of an automated method for determination of bone age and (cortical) bone mineral density (cBMD) in severely affected JIA patients. A secondary objective was to describe bone age and cBMD in this specific JIA population eligible for biologic treatment.

Methods

In total, 69 patients with standard hand radiographs at the start of etanercept treatment and of calendar age within the reliability ranges (2.5 to 17 years for boys and 2 to 15 years for girls) were extracted from the Dutch Arthritis and Biologicals in Children register. Radiographs were analyzed using the BoneXpert method, thus automatically determining bone age and cBMD expressed as bone health index (BHI). Agreement between measurements of the left- and right-hand radiographs and a repeated measurement of the left hand were assessed with the intraclass correlation coefficient (ICC). Regression analysis was used to identify variables associated with Z-scores of bone age and BHI.

Results

The BoneXpert method was reliable in the evaluation of radiographs of 67 patients (radiographs of 2 patients were rejected because of poor image quality). Agreement between left- and right-hand radiographs (ICC = 0.838 to 0.996) and repeated measurements (ICC = 0.999 to 1.000) was good. Mean Z-scores of bone age (−0.36, P = 0.051) and BHI (−0.85, P < 0.001) were lower compared to the healthy population. Glucocorticoid use was associated with delayed bone age (0.79 standard deviation (SD), P = 0.028), and male gender was associated with a lower Z-score of BHI (0.65 SD, P = 0.021).

Conclusions

BoneXpert is an easy-to-use method for assessing bone age and cBMD in patients with JIA, provided that radiographs are of reasonable quality and patients’ bone age lies within the age ranges of the program. The population investigated had delayed bone maturation and lower cBMD than healthy children.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-014-0424-1) contains supplementary material, which is available to authorized users.

Comparison of radiogrammetrical metacarpal indices in children and reference data from the First Zurich Longitudinal Study

BACKGROUND

A number of radiogrammetrical metacarpal indices are in use, some of which have been adapted for children.

OBJECTIVE

The purpose of this study was to compare four known indices-bone mineral density (BMD), relative cortical area, Exton-Smith index, bending breaking resistance index-and the more recently defined pediatric bone index (PBI) according to the two criteria of minimum height dependence and minimum variability in children of equal bone age.

MATERIALS AND METHODS

A total of 3,121 left-hand radiographs from 231 healthy Caucasian children ranging in age from 3 to 19 years old were analysed using BoneXpert®, a programme for automatic analysis of hand radiographs and assessment of bone age.

RESULTS

Dependence on height for chronological age or bone age and the mean relative standard deviation were lowest in the PBI for both genders pooled. The differences in height dependence were statistically significant and are shown to be clinically relevant. Reference data for PBI are presented.

CONCLUSION

PBI may be a better indicator than BMD for bone health in children; however, verification in a clinical group is needed.

Metacarpal thickness, width, length and medullary diameter in children--reference curves from the First Zürich Longitudinal Study

SUMMARY

Metacarpal thickness (T), width (W), length (L) and medullary diameter (M) were measured in 3,121 X-rays from 231 healthy Caucasian children aged 3 to 19 years and analysed for bone age, age, height, weight and gender-related characteristics, showing highly differentiated growth patterns with prepubertal dips. Reference data for the four metacarpal measures are presented.

INTRODUCTION

The aim of the study was to create and explore a reference database for metacarpal T, W, L and M in children.

METHODS

Three thousand one hundred twenty-one left-hand X-rays (1,661 from boys) from 231 healthy Caucasian subjects (119 boys) aged 3 to 19 years were analysed by BoneXpert, a programme for automatic analysis of hand X-rays and bone age (BA; in years).

RESULTS

In boys, growth of T, W and L shows a prepubertal decrease from BA 7 to 13 and then accelerates again. In girls, the same is seen only for T starting from BA 8 to 11, whereas W and L grow at a declining rate. M shows steady growth until BA 10.5 in girls and BA 13.5 in boys and then grows smaller in both. W is greater in boys from BA 6 onwards, while L is greater in girls from BA 9 to 13 and T from BA 11 to 14. BA is reflected best by L until start of puberty and by T and L thereafter.

CONCLUSION

T, W, L and M show highly differentiated growth patterns. These reference data provide a basis for further research into skeletal development and the management of hormone therapies in children.

Longitudinal study of bone mineral density in children after a diagnosis of Crohn's disease

AIM

The purpose of this study was to measure the bone mineral density (BMD) of children with Crohn's disease (CD) and to prospectively assess its evolution.

PATIENTS AND METHODS

A total of 27 children (20 boys, seven girls), aged 12.1±2.5 years, were recruited at the time of CD diagnosis. Dual-energy X-ray absorptiometry (DEXA) was used to measure BMD, expressed as Z scores for chronological age (BMD/CA) and bone age (BMD/BA). One year later, BMD was measured again to identify any correlations with disease activity [group A (active disease) vs group R (remission)].

RESULTS

BMD/CA and BMD/BA were negatively correlated with delay in diagnosis (P<0.0001 and P<0.05, respectively). BMD/CA was less than -2 standard deviation (SD) in nine patients and BMD/BA was less -2 SD in four patients. At the follow-up, the increase in BMD was smaller in group A (n=14), whether expressed as absolute values (-0.002 vs 0.040 g/cm(2) per year; P<0.024) or as percentages (-0.2 vs 6.6%; P<0.041); changes in BMD/CA (-0.5 vs -0.1 SD/year) and BMD/BA (-0.3 vs 0 SD/year) did not differ.

CONCLUSION

Diagnostic delay greatly affects BMD in children with CD even prior to corticosteroid therapy. The risk of low BMD increases with persistent CD activity, although the risk is reduced in association with bone maturation delay.

Radiogrammetry and radiographic absorptiometry

Metacarpal morphometry and radiogrammetry are the oldest methods for quantitative assessment of the skeleton. The historical aspects of these measurements are reviewed. Although they were inexpensive and widely available and provided useful research and epidemiologic information, they were labor intensive and imprecise. They were replaced with the current established methods of bone mineral densitometry. With the application of modern computer vision techniques, metacarpal morphometric analysis has been rejuvenated, with improvement in precision and evidence that the method can be applied to studies in adults and children. Evidence for limited normal reference data and the ability to predict future fractures in osteoporosis and reflect activity and predict outcomes in rheumatoid arthritis are presented.