Radiation exposure in X-ray-based imaging techniques used in osteoporosis

Skeletal muscle estimation: A review of techniques and their applications

Quantifying skeletal muscle size is necessary to identify those at risk for conditions that increase frailty, morbidity, and mortality, as well as decrease quality of life. Although muscle strength, muscle quality, and physical performance have been suggested as important assessments in the screening, prevention, and management of sarcopenic and cachexic individuals, skeletal muscle size is still a critical objective marker. Several techniques exist for estimating skeletal muscle size; however, each technique presents with unique characteristics regarding simplicity/complexity, cost, radiation dose, accessibility, and portability that are important factors for assessors to consider before applying these modalities in practice. This narrative review presents a discussion centred on the theory and applications of current non-invasive techniques for estimating skeletal muscle size in diverse populations. Common instruments for skeletal muscle assessment include imaging techniques such as computed tomography, magnetic resonance imaging, peripheral quantitative computed tomography, dual-energy X-ray absorptiometry, and Brightness-mode ultrasound, and non-imaging techniques like bioelectrical impedance analysis and anthropometry. Skeletal muscle size can be acquired from these methods using whole-body and/or regional assessments, as well as prediction equations. Notable concerns when conducting assessments include the absence of standardised image acquisition/processing protocols and the variation in cut-off thresholds used to define low skeletal muscle size by clinicians and researchers, which could affect the accuracy and prevalence of diagnoses. Given the importance of evaluating skeletal muscle size, it is imperative practitioners are informed of each technique and their respective strengths and weaknesses.

Raman spectroscopic analysis for osteoporosis identification in humans with hip fractures

Osteoporosis is a significant health concern. While multiple techniques have been utilized to diagnose this condition, certain limitations still persist. Raman spectroscopy has shown promise in predicting bone strength in animal models, but its application to humans requires further investigation. In this study, we present an in vitro approach for predicting osteoporosis in 10 patients with hip fractures using Raman spectroscopy. Raman spectra were acquired from exposed femoral heads collected during surgery. Employing a leave-one-out cross-validated linear discriminant analysis (LOOCV-LDA), we achieved accurate classification (90 %) between osteoporotic and osteopenia groups. Additionally, a LOOCV partial least squares regression (PLSR) analysis based on the complete Raman spectra demonstrated a significant prediction (r2 = 0.84, p < 0.05) of bone mineral density as measured by dual X-ray absorptiometry (DXA). To the best of our knowledge, this study represents the first successful demonstration of Raman spectroscopy correlating with osteoporotic status in humans.

Association of osteoporotic fractures of femoral neck and femoral neck geometric parameters in native Chinese women

BACKGROUND

Although it is generally believed that the femoral neck fracture is related to the femoral neck geometric parameters (FNGPs), the association between the risk of osteoporotic fracture of the femoral neck and FNGPs in native Chinese women is still unclear.

METHODS

A total of 374 female patients (mean age 70.2 ± 9.32 years) with osteoporotic fracture of the femoral neck, and 374 non-fracture control groups were completely matched with the case group according to the age ratio of 1:1. Using DXA bone densitometer to measured eight FNGPs: the outer diameter (OD), cross-sectional area (CSA), cortical thickness (CT), endocortical diameter (ED), buckling ratio (BR), section modulus (SM), cross-sectional moment of inertia (CSMI), and compressive strength index (CSI) at the narrowest point of the femoral neck.

RESULTS

Compared with the control group, the average values of OD (2.9%), ED (4.5%), and BR (26.1%) in the patient group significantly increased (p = 0.015 to < 0.001), while CSA (‒15.3%), CT (‒18.2%), SM (‒10.3%), CSMI (‒6.4%), and CSI (‒10.8%) significantly decreased (all p < 0.001). The prevalence of osteoporosis in the lumbar spine, femoral neck, and total hip was, respectively, 82%, 81%, and 65% in fracture patients. Cox proportional hazard model analysis showed that in the age adjusted model, the fracture hazard ratio (HR) of CSA, CT, BR, SM, and CSI significantly increased (HRs = 1.60‒8.33; 95% CI = 1.08‒16.6; all p < 0.001). In the model adjusted for age and femoral neck BMD, HRs of CT (HRs = 3.90‒8.03; 95% CI = 2.45‒15.1; all p < 0.001) and BR (HRs = 1.62‒2.60; 95% CI = 1.20‒5.44; all p < 0.001) were still significantly increased.

CONCLUSION

These results suggest that the majority of osteoporotic fractures of the femoral neck of native Chinese women occur in patients with osteoporosis. CT thinning or BR increase of FNGPs may be independent predictors of fragility fracture of femoral neck in native Chinese women unrelated to BMD.

State of the Art Imaging of Osteoporosis

Osteoporosis is a common disease, particularly prevalent in geriatric populations, which causes significant worldwide morbidity due to increased bone fragility and fracture risk. Currently, the gold-standard modality for diagnosis and evaluation of osteoporosis progression and treatment relies on dual-energy x-ray absorptiometry (DXA), which measures bone mineral density (BMD) and calculates a score based upon standard deviation of measured BMD from the mean. However, other imaging modalities can also be used to evaluate osteoporosis. Here, we review historical as well as current research into development of new imaging modalities that can provide more nuanced or opportunistic analyses of bone quality, turnover, and density that can be helpful in triaging severity and determining treatment success in osteoporosis. We discuss the use of opportunistic computed tomography (CT) scans, as well as the use of quantitative CT to help determine fracture risk and perform more detailed bone quality analysis than would be allowed by DXA . Within magnetic resonance imaging (MRI), new developments include the use of advanced MRI techniques such as quantitative susceptibility mapping (QSM), magnetic resonance spectroscopy, and chemical shift encoding-based water-fat MRI (CSE-MRI) to enable clinicians improved assessment of nonmineralized bone compartments as well as a way to longitudinally assess bone quality without the repeated exposure to ionizing radiation. Within ultrasound, development of quantitative ultrasound shows promise particularly in future low-cost, broadly available screening tools. We focus primarily on historical and recent developments within radiotracer use as applicable to osteoporosis, particularly in the use of hybrid methods such as NaF-PET/CT, wherein patients with osteoporosis show reduced uptake of radiotracers such as NaF. Use of radiotracers may provide clinicians with even earlier detection windows for osteoporosis than would traditional biomarkers. Given the metabolic nature of this disease, current investigation into the role molecular imaging can play in the prediction of this disease as well as in replacing invasive diagnostic procedures shows particular promise.

From imaging to precision: low cost and accurate determination of stereotactic coordinates for brain surgery Sapajus apella using MRI

The capuchin monkey (Sapajus apella), a New World monkey species, exhibits prominent characteristics that make it an ideal model for neuroscience research. These characteristics include its phylogenetic traits, telencephalization coefficient, anatomical structures and pathways, genetic profile, immune responses, cognitive abilities, and complex behavioral repertoires. Traditionally, methodologies for stereotactic neurosurgery in research models have relied on the use of brain atlases. However, this approach can lead to errors due to the considerable variation in brain size and shape among individual monkeys. To address this issue, we developed a protocol for deriving individual coordinates for each monkey using a straightforward and relatively inexpensive method involving MRI imaging. Our protocol utilizes a specially designed, 3D-printed stereotactic head-holder that is safe to use with an MR magnet, non-invasive placement of fiducial markers, and post-processing with open-source software. This approach enhances MRI data visualization, improves anatomical targeting, and refines the design of neurosurgical experiments. Our technique could also prove beneficial in other areas of neuroscience research that require accurate calculation of stereotaxic coordinates. Furthermore, it could be useful for other nonhuman primate species for which brain atlases are typically unavailable.

Potential endpoints for assessment of bone health in persons with neurofibromatosis type 1

Neurofibromatosis type 1 is a genetic syndrome characterized by a wide variety of tumor and non-tumor manifestations. Bone-related issues, such as scoliosis, tibial dysplasia, and low bone mineral density, are a significant source of morbidity for this population with limited treatment options. Some of the challenges to developing such treatments include the lack of consensus regarding the optimal methods to assess bone health in neurofibromatosis type 1 and limited data regarding the natural history of these manifestations. In this review, the Functional Committee of the Response Evaluation in Neurofibromatosis and Schwannomatosis International Collaboration: (1) presents the available techniques for measuring overall bone health and metabolism in persons with neurofibromatosis type 1, (2) reviews data for use of each of these measures in the neurofibromatosis type 1 population, and (3) describes the strengths and limitations for each method as they might be used in clinical trials targeting neurofibromatosis type 1 bone manifestations. The Response Evaluation in Neurofibromatosis and Schwannomatosis International Collaboration supports the development of a prospective, longitudinal natural history study focusing on the bone-related manifestations and relevant biomarkers of neurofibromatosis type 1. In addition, we suggest that the neurofibromatosis type 1 research community consider adding the less burdensome measurements of bone health as exploratory endpoints in ongoing or planned clinical trials for other neurofibromatosis type 1 manifestations to expand knowledge in the field.

Quantifying Bone Strength Deficits in Young Adults Born Extremely Preterm or Extremely Low Birth Weight

The long-term bone health of young adults born extremely preterm (EP; <28 weeks' gestation) or extremely low birth weight (ELBW; <1000 g birth weight) in the post-surfactant era (since the early 1990s) is unclear. This study investigated their bone structure and estimated bone strength using peripheral quantitative computed tomography (pQCT)-based finite element modeling (pQCT-FEM). Results using this technique have been associated with bone fragility in several clinical settings. Participants comprised 161 EP/ELBW survivors (46.0% male) and 122 contemporaneous term-born (44.3% male), normal birth weight controls born in Victoria, Australia, during 1991-1992. At age 25 years, participants underwent pQCT at 4% and 66% of tibia and radius length, which was analyzed using pQCT-FEM. Groups were compared using linear regression and adjusted for height and weight. An interaction term between group and sex was added to assess group differences between sexes. Parameters measured included compressive stiffness (kcomp ), torsional stiffness (ktorsion ), and bending stiffness (kbend ). EP/ELBW survivors were shorter than the controls, but their weights were similar. Several unadjusted tibial pQCT-FEM parameters were lower in the EP/ELBW group. Height- and weight-adjusted ktorsion at 66% tibia remained lower in EP/ELBW (mean difference [95% confidence interval] -180 [-352, -8] Nm/deg). The evidence for group differences in ktorsion and kbend at 66% tibia was stronger among males than females (pinteractions  <0.05). There was little evidence for group differences in adjusted radial models. Lower height- and weight-adjusted pQCT-FEM measures in EP/ELBW compared with controls suggest a clinically relevant increase in predicted long-term fracture risk in EP/ELBW survivors, particularly males. Future pQCT-FEM studies should utilize the tibial pQCT images because of the greater variability in the radius possibly related to lower measurement precision. © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Computed Tomography Provides Improved Quantification of Trabecular Lumbar Spine Bone Loss Compared to Dual-Energy X-Ray Absorptiometry in Ovariectomized Sheep

Early detection of osteoporosis using advanced imaging is imperative to the successful treatment and prevention of high morbidity fractures in aging patients. In this preclinical study, we aimed to compare dual-energy X-ray absorptiometry (DXA) and quantitative computed tomography (QCT) to quantify bone mineral density (BMD) changes in the sheep lumbar spine. We also aimed to determine the relationship of BMD to microarchitecture in the same animals as an estimate of imaging modality precision. Osteoporosis was induced in 10 ewes via laparoscopic ovariectomy and administration of high-dose corticosteroids. We performed DXA and QCT imaging to measure areal BMD (aBMD) and trabecular volumetric BMD (Tb.vBMD)/cortical vBMD (Ct.vBMD), respectively, at baseline (before ovariectomy) and at 3, 6, 9, and 12 months after ovariectomy. Iliac crest bone biopsies were collected at each time point for micro-computed tomography (microCT) analysis; bone volume fraction (BV/TV), trabecular number (Tb.N), thickness (Tb.Th), and spacing (Tb.Sp) were reported. aBMD and Tb.vBMD both decreased significantly by 3 and 6 months (p < 0.05) compared with baseline, whereas no changes to Ct.vBMD were observed. Combined (Tb. and Ct.) vBMD was significantly correlated with aBMD at all time points (all p < 0.05). Additionally, greater significant correlations were found between BV/TV and Tb.vBMD at all five time points (R 2 = 0.54, 0.57, 0.66, 0.46, and 0.56, respectively) than with aBMD values (R 2 = 0.23, 0.55, 0.41, 0.20, and 0.19, respectively). The higher correlation of microCT values with QCT than with DXA indicates that QCT provides additional detailed information regarding bone mineral density changes in preclinical settings. Because trabecular bone is susceptible to rapid density loss and structural changes during osteoporosis, QCT can capture these subtle changes more precisely than DXA in a large animal preclinical model. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

FR. DEXA and Imaging in Osteoporosis

Background

Reduced bone density and increased fragility are hallmarks of osteoporosis, making the disease a major public health concern. The disease necessitates early diagnosis and appropriate therapy depend on an accurate evaluation of bone health. Essential tools for assessing osteoporosis include dual-energy X-ray absorptiometry (DEXA) and other imaging modalities.

Methods

This chapter focuses on dual-energy X-ray absorptiometry (DEXA) and other imaging methods as essential tools for assessment of osteoporosis. The chapter also explores complementary imaging modalities that help overcome limitation of DEXA by providing insights into the microarchitecture and bone quality.

Results

T-scores, used to categorise bone health, are determined by DEXA by comparing bone mineral density to age-matched standards. Bone mineral density (BMD) is the most common indicator of bone health; nevertheless, DEXA may misclassify bone health owing to reasons other than BMD. These constraints may be overcome with the use of complementary imaging methods, which provide information on the microarchitecture and quality of bone. The evaluation of bone structure is aided by high-resolution peripheral quantitative computed tomography (HR-pQCT), which produces precise 3D images of the trabecular and cortical bone compartments. Independent of traditional methods of gauging fracture risk, quantitative ultrasonography (QUS) uses an analysis of the characteristics of sound waves to determine bone health. Diagnostic precision is improved by magnetic resonance imaging (MRI) due to its ability to view bone marrow and trabecular structure without the use of ionising radiation.

Discussion

New methods, such as the trabecular bone score (TBS), examine bone texture and provide more data on the likelihood of fracture than conventional DEXA. By modelling bone strength using imaging data, finite element analysis (FEA) provides a biomechanical viewpoint on breakage probability. These combined methods boost diagnostic accuracy and pave the way for individualised treatment plans. Imaging helps with therapy monitoring as well as diagnosis. By monitoring bone density and structure over time, therapy effectiveness or course corrections may be quickly identified. The availability of sophisticated imaging techniques and the standardisation of procedures provide obstacles not withstanding their advantages. Ongoing work is being done to solve these issues and standardise and disseminate these methods in a variety of contexts.

Conclusion

The evaluation of osteoporosis is significantly aided by DEXA and other imaging methods. While DEXA is still the gold standard for diagnosing osteoporosis, other imaging techniques may shed light on bone health in greater detail. These methods improve fracture risk prediction and treatment assessment by providing information on bone architecture, quality, and strength. Integration of several imaging modalities shows potential for bettering osteoporosis therapy and patient outcomes as the field develops.

Establishing national diagnostic reference levels in radiography, mammography, and dual-energy x-ray absorptiometry services in Ireland and comparing these with European diagnostic reference levels

OBJECTIVES

The aim of this work was to establish national diagnostic reference levels (DRLs) in Ireland and compare these to existing European DRLs where available. This work surveyed all radiological facilities providing radiography, mammography, and dual-energy x-ray absorptiometry (DXA) services in Ireland.

METHODS

A list of common procedures and clinical tasks was established. A national database of service providers was used to identify the appropriate medical radiological facilities providing these services. These facilities were issued with an online survey. National DRLs were set as the 75th percentile of the distribution of median values obtained. A national median dose was also established. The broad categorisation of equipment type was also considered. Where differences between DRLs established using different detector types were deemed statistically significant, equipment-specific national DRLs were established.

RESULTS

National DRLs were established for 12 adult radiography projections. Equipment-specific (computed radiography and digital radiography) adult DRLs were established for four radiography projections. Paediatric DRLs were established for 11 radiography projections, including two based on clinical indications, for a range of paediatric weight categories. National DRLs were established for unilateral two-view mammography and breast tomosynthesis as well as for four DXA clinical indications and projections. All but one Irish DRL figure was found to be below or equal to European data.

CONCLUSIONS

This work provided a unique opportunity to establish national DRLs based on census data for a range of procedures and clinical tasks across radiography, mammography and DXA and compare these with European levels.

CLINICAL RELEVANCE STATEMENT

This work established national diagnostic reference levels (DRLs) based on census data for a range of procedures and clinical tasks across radiography, mammography and dual-energy x-ray absorptiometry. The establishment of national DRLs is an essential component in the optimisation of patient radiation dose.

KEY POINTS

• Diagnostic reference levels are easily measured quantities intended for use as an aid to optimise patient dose and to identify when levels of patient dose are unusually high. • Data from all medical radiological facilities in Ireland was obtained to establish national diagnostic reference level (DRL) values and national median dose values in radiography, x-ray breast imaging and dual-energy x-ray absorptiometry (DXA) scanning and these were compared to existing European DRLs where available. • National DRL values were established for the first time in breast tomosynthesis, DXA scanning, and paediatric radiography.

Artificial Intelligence Applications for Osteoporosis Classification Using Computed Tomography

Osteoporosis, marked by low bone mineral density (BMD) and a high fracture risk, is a major health issue. Recent progress in medical imaging, especially CT scans, offers new ways of diagnosing and assessing osteoporosis. This review examines the use of AI analysis of CT scans to stratify BMD and diagnose osteoporosis. By summarizing the relevant studies, we aimed to assess the effectiveness, constraints, and potential impact of AI-based osteoporosis classification (severity) via CT. A systematic search of electronic databases (PubMed, MEDLINE, Web of Science, ClinicalTrials.gov) was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A total of 39 articles were retrieved from the databases, and the key findings were compiled and summarized, including the regions analyzed, the type of CT imaging, and their efficacy in predicting BMD compared with conventional DXA studies. Important considerations and limitations are also discussed. The overall reported accuracy, sensitivity, and specificity of AI in classifying osteoporosis using CT images ranged from 61.8% to 99.4%, 41.0% to 100.0%, and 31.0% to 100.0% respectively, with areas under the curve (AUCs) ranging from 0.582 to 0.994. While additional research is necessary to validate the clinical efficacy and reproducibility of these AI tools before incorporating them into routine clinical practice, these studies demonstrate the promising potential of using CT to opportunistically predict and classify osteoporosis without the need for DEXA.

A Survey on Artificial Intelligence in Pulmonary Imaging

Over the last decade, deep learning (DL) has contributed a paradigm shift in computer vision and image recognition creating widespread opportunities of using artificial intelligence in research as well as industrial applications. DL has been extensively studied in medical imaging applications, including those related to pulmonary diseases. Chronic obstructive pulmonary disease, asthma, lung cancer, pneumonia, and, more recently, COVID-19 are common lung diseases affecting nearly 7.4% of world population. Pulmonary imaging has been widely investigated toward improving our understanding of disease etiologies and early diagnosis and assessment of disease progression and clinical outcomes. DL has been broadly applied to solve various pulmonary image processing challenges including classification, recognition, registration, and segmentation. This paper presents a survey of pulmonary diseases, roles of imaging in translational and clinical pulmonary research, and applications of different DL architectures and methods in pulmonary imaging with emphasis on DL-based segmentation of major pulmonary anatomies such as lung volumes, lung lobes, pulmonary vessels, and airways as well as thoracic musculoskeletal anatomies related to pulmonary diseases.

What are the risk factors for a second osteoporotic vertebral compression fracture?

BACKGROUND CONTEXT

Osteoporosis is characterized by decreased bone strength and an increased risk of fracture. Osteoporosis-related fractures are associated with increased morbidity, mortality, dysfunction, access to health care, health-care costs, and reduced quality of life. Therefore, preventing osteoporotic vertebral compression fractures (OVCF) is important. Secondary OVCFs often occur after the first OVCF.

PURPOSE

This study aimed to identify risk factors for a second OVCF after a first OVCF.

STUDY DESIGN

Retrospective observational study.

PATIENT SAMPLE

One hundred seventy-eight patients from a single institution who had their first OVCF between January 1, 2000 and December 31, 2019 were enrolled in this study.

OUTCOME MEASURES

The following data were observed for all cases: patient demographics, bone mineral density, and pelvic parameters.

METHODS

We retrospectively reviewed patients from a single institution who had their first OVCF between January 1, 2000 and December 31, 2019. Demographic factors, medication (oral bisphosphonate, zoledronic acid, denosumab), bone mineral density (BMD), body mass index (BMI), fat, and muscle amount of the trunk using dual-energy X-ray absorptiometry (DEXA), and pelvic parameters (lumbar lordosis, sacral slope, pelvic tilt, pelvic incidence minus lumbar lordosis) were investigated.

RESULTS

Of 178 patients who had an OVCF, 68 (38.2%) had a second OVCF. Patients were followed up for >2 years and wore braces for an average of 6 months. The mean age was 71.9±8.63 years, mean BMD T-score was -3.1±1.09, and mean BMI was 23.3±2.96. Comparing those with and without a second OVCF, the smaller the BMD T-score and trunk muscle mass to fat ratio, the more likely a second OVCF occurred (p<.05). There were fewer second OVCF cases in the injection medication group than in the peroral group (p<.05). There were no significant differences in radiologic parameters between these groups.

CONCLUSIONS

Patients who had a second OVCF had an average of 21.3 months after the first OVCF. Risk factors for a second OVCF are low T-scores in the femur, and low M/F ratio of the trunk, android, and gynoid regions. For patients with an OVCF, injection medications may be advisable.

CT and MR for bone mineral density and trabecular bone score assessment in osteoporosis evaluation

Dual energy X-ray absorptiometry (DXA) is widely used modality for measuring bone mineral density (BMD). DXA is used to measure the quantitative areal BMD of bone, but has the disadvantage of not reflecting the bone architecture. To compensate for this disadvantage, trabecular bone score (TBS), a qualitative parameter of trabecular microarchitecture, is used. Meanwhile, there have been recent attempts to diagnose osteoporosis using the Hounsfield unit (HU) from CT and MR-based proton density fat fraction (PDFF) measurements. In our study, we aimed to find out the correlation between HU/PDFF and BMD/TBS, and whether osteoporosis can be diagnosed through HU/PDFF. Our study revealed that the HU value showed a moderate to good positive correlation with BMD and TBS. PDFF showed a fair negative correlation with BMD and TBS. In diagnosing osteopenia and osteoporosis, the HU value showed good performance, whereas the PDFF showed fair performance. In conclusion, both HU values and PDFF can play a role in predicting BMD and TBS. Both HU values and PDFF can be used to predict osteoporosis; further, CT is expected to show better results.

Prenatal and Neonatal Bone Health: Updated Review on Early Identification of Newborns at High Risk for Osteopenia

Bone health starts with maternal health and nutrition, which influences bone mass and density already in utero. The mechanisms underlying the effect of the intrauterine environment on bone health are partly unknown but certainly include the 'foetal programming' of oxidative stress and endocrine systems, which influence later skeletal growth and development. With this narrative review, we describe the current evidence for identifying patients with risk factors for developing osteopenia, today's management of these populations, and screening and prevention programs based on gestational age, weight, and morbidity. Challenges for bone health prevention include the need for new technologies that are specific and applicable to pregnant women, the foetus, and, later, the newborn. Radiofrequency ultrasound spectrometry (REMS) has proven to be a useful tool in the assessment of bone mineral density (BMD) in pregnant women. Few studies have reported that transmission ultrasound can also be used to assess BMD in newborns. The advantages of this technology in the foetus and newborn are the absence of ionising radiation, ease of use, and, above all, the possibility of performing longitudinal studies from intrauterine to extrauterine life. The use of these technologies already in the intrauterine period could help prevent associated diseases, such as osteoporosis and osteopenia, which are characterised by a reduction in bone mass and degeneration of bone structure and lead to an increased risk of fractures in adulthood with considerable social repercussions for the related direct and indirect costs.

Ultrasound Characterization of Cortical Bone Using Shannon Entropy

OBJECTIVE

Ultrasound backscattered signals encompass information on the microstructure of heterogeneous media such as cortical bone, in which pores act as scatterers and result in the scattering and multiple scattering of ultrasound waves. The objective of this study was to investigate whether Shannon entropy can be exploited to characterize cortical porosity.

METHODS

In the study described here, to demonstrate proof of concept, Shannon entropy was used as a quantitative ultrasound parameter to experimentally evaluate microstructural changes in samples with controlled scatterer concentrations made of a highly absorbing polydimethylsiloxane matrix (PDMS). Similar assessment was then performed using numerical simulations on cortical bone structures with varying average pore diameter (Ct.Po.Dm.), density (Ct.Po.Dn.) and porosity (Ct.Po.).

RESULTS

The results suggest that an increase in pore diameter and porosity lead to an increase in entropy, indicating increased levels of randomness in the signals as a result of increased scattering. The entropy-versus-scatterer volume fraction in PDMS samples indicates an initial increasing trend that slows down as the scatterer concentration increases. High levels of attenuation cause the signal amplitudes and corresponding entropy values to decrease drastically. The same trend is observed when porosity of the bone samples is increased above 15%.

CONCLUSION

Sensitivity of entropy to microstructural changes in highly scattering and absorbing media can potentially be exploited to diagnose and monitor osteoporosis.

Skeletal effects of eccentric strengthening exercise: a scoping review

BACKGROUND

Conventional progressive concentric strengthening exercise (CSE) to improve bone mineral density (BMD) and bone mineral content (BMC) may not be feasible for populations with chronic musculoskeletal and/or metabolic conditions, such as osteoporosis or obesity. Muscle lengthening exercise, also known as an eccentric strengthening exercise (ESE), may have a special utility for those populations due to greater force generation versus CSE. In fact, greater mechanical loading can be induced on bone at lower resistance levels with ESE. However, effects of ESE on BMD and BMC are unclear. Thus, the purpose of this review was to interrogate the effects of ESE on BMD and BMC.

METHODS

A literature review was conducted between January 1995 and April 2022 focusing on randomized controlled trials investigating the effects of ESE on BMD and/or BMC in humans. Terms covering the domains of exercise, bone, and populations were searched on PubMed, CINAHL, and Scopus. The methodological quality of each interventional study was rated using Physiotherapy Evidence Database (PEDro) scale. Cohen's d was calculated to determine the magnitude of the effects of ERE on site-specific outcome measures of BMD and/or BMC.

RESULTS

Out of 1,182 articles initially found, a total of seven full length articles met our inclusion criteria. Of the seven studies, most of the interventions were performed in young (n = 5, PEDro = 5-7) versus middle-aged (n = 1, PEDro = 4) or older (n = 1, PEDro = 6) adults. BMD and BMC generally improved due to ESE; however the effects of ESE on BMD and BMC were non-homogenous. Effect size (d) ranged from 0.10-0.87 in young adults while it was 1.16 in older adults. Effect size (d) could not be calculated for the middle-aged adult study due to critical methodological limitations of the intervention.

CONCLUSIONS

Large variability exists for the effectiveness of ESE on BMD/BMC across the human life spectrum. The benefits of ESE on BMD holds promise but rigorous studies are lacking. Further research is needed to examine if the dose, mode, age, and sex-specificity dictate effects of ESE on BMD/BMC.

Comparative analysis of bone outcomes between quantitative ultrasound and dual-energy x-ray absorptiometry from the UK Biobank cohort

This large cohort study investigated reliability and validity of heel ultrasound to estimate bone mineral density in adults. Reliability calculated between left and right heels was relatively poor and so was criterion validity assessed relative to dual-energy X-ray absorptiometry. Heel ultrasound should be used cautiously when estimating bone mineral density.

INTRODUCTION

Calcaneal quantitative ultrasound (QUS) may be used as a safe, low cost, and portable means to estimate bone mineral density (BMD) in large cohorts. The purpose of this study was to quantify the reliability and validity of QUS in comparison to dual-energy X-ray absorptiometry (DXA), which is the reference method for BMD measurement and diagnoses of osteopenia and osteoporosis.

METHODS

Bone outcomes measured on the large UK Biobank cohort were used. The reliability of QUS estimated BMD was quantified by comparing values obtained from the left and right heel measured in the same session. Criterion validity was assessed through agreement between QUS and DXA, quantifying correlations, and sensitivity and specificity of osteopenia and osteoporosis diagnoses.

RESULTS

Reliability calculations were made using data from over 216,000 participants demonstrating similar QUS BMD values between left and right heels in the absolute scale (Sd of difference for men: 0.12 and 0.07 g·cm-2). However, when expressed in relative scales, including concordance of quartiles, reliability was poor. Agreement between QUS and DXA was quantified using data from 5042 participants. Low to modest correlations (r = 0.29 to 0.44) were obtained between multiple QUS variables and DXA BMD, with sensitivity identified as very poor (0.05 to 0.23) for osteoporosis, and poor (0.37 to 0.62) for osteopenia diagnoses.

CONCLUSIONS

The findings of this large comparative analysis identify that whilst calcaneal QUS has the potential to produce reliable absolute BMD measurements and demonstrate modest associations with DXA BMD measures, use of that information to make relative statements about participants in the context of the larger population or to appropriately diagnose osteopenia or osteoporosis may be severely limited.

Can Ultrasonographic Measurement of Bone Cortical Thickness Predict Osteoporosis?

RATIONALE AND OBJECTIVES

In this study, we aimed to describe a more accessible and safe diagnostic tool for osteoporosis or osteopenia diagnosis. We utilized cortical thickness (CoT) measurement of various bones via ultrasonography and evaluated the method's accuracy relative to bone mineral density (BMD) results determined by dual-energy X-ray absorptiometry (DXA).

MATERIALS AND METHODS

A total of 200 volunteers (all female) who agreed to participate in the study and had undergone BMD measurement (femoral or vertebral) were included in the study. Patients with normal BMD result (≥-1.0 T-score) were defined as controls. CoT measurements were made from three bones (radius, tibia, and second metatarsal) for each patient via ultrasonography.

RESULTS

Radius CoT and tibial CoT measurements of both femoral and vertebral osteoporotic or osteopenic patients were significantly higher compared to controls. Second metatarsal CoT of femoral osteoporotic and osteopenic patients was also found to be significantly higher than the control group. We found tibia CoT and radius CoT to have high sensitivity and positive predictive value in identifying patients with abnormal femoral T-scores (<-1). In multivariable analyzes, radius CoT was found to be independently predictive in distinguishing patients with abnormal T-score (<-1) from controls in both the femur and vertebral BMD groups.

CONCLUSION

Radius CoT and tibia CoT values appear to have value in predicting patients with abnormal T-scores measured via DXA. This method may be a very simple technique that can be used for early detection of osteoporosis and osteopenia, but its results need to be supported by more comprehensive studies.

Multicompartment body composition analysis in older adults: a cross-sectional study

BACKGROUND

During aging, changes occur in the proportions of muscle, fat, and bone. Body composition (BC) alterations have a great impact on health, quality of life, and functional capacity. Several equations to predict BC using anthropometric measurements have been developed from a bi-compartmental (2-C) approach that determines only fat mass (FM) and fat-free mass (FFM). However, these models have several limitations, when considering constant density, progressive bone demineralization, and changes in the hydration of the FFM, as typical changes during senescence. Thus, the main purpose of this study was to propose and validate a new multi-compartmental anthropometric model to predict fat, bone, and musculature components in older adults of both sexes.

METHODS

This cross-sectional study included 100 older adults of both sexes. To determine the dependent variables (fat mass [FM], bone mineral content [BMC], and appendicular lean soft tissue [ALST]) whole total and regional dual-energy X-ray absorptiometry (DXA) body scans were performed. Twenty-nine anthropometric measures and sex were appointed as independent variables. Models were developed through multivariate linear regression. Finally, the predicted residual error sum of squares (PRESS) statistic was used to measure the effectiveness of the predicted value for each dependent variable.

RESULTS

An equation was developed to simultaneously predict FM, BMC, and ALST from only four variables: weight, half-arm span (HAS), triceps skinfold (TriSK), and sex. This model showed high coefficients of determination and low estimation errors (FM: R²_adj: 0.83 and SEE: 3.16; BMC: R²_adj: 0.61 and SEE: 0.30; ALST: R²_adj: 0.85 and SEE: 1.65).

CONCLUSION

The equations provide a reliable, practical, and low-cost instrument to monitor changes in body components during the aging process. The internal cross-validation method PRESS presented sufficient reliability in the model as an inexpensive alternative for clinical field use.

Effect of the GLP-1 receptor agonist semaglutide on metabolic disturbances in clozapine-treated or olanzapine-treated patients with a schizophrenia spectrum disorder: study protocol of a placebo-controlled, randomised clinical trial (SemaPsychiatry)

INTRODUCTION

Clozapine and olanzapine are some of the most effective antipsychotics, but both are associated with weight gain and relevant metabolic disturbances, including pre-diabetes and diabetes. Non-pharmacological/behavioural interventions have had limited effects counteracting these adverse effects. Semaglutide, a glucagon-like peptide 1 receptor agonist, is approved for the treatment of type 2 diabetes and obesity. We will investigate the long-term effects of add-on treatment with semaglutide once a week versus placebo once a week on the metabolic status in pre-diabetic (glycated haemoglobin A1c (HbA1c) 35-47 mmol/mol (5.4%-6.4%) and diabetic (HbA1c 48-57 mmol/mol (6.5%-7.4%)) patients diagnosed with a schizophrenia spectrum disorder who initiated clozapine or olanzapine treatment within the last 60 months.

METHODS AND ANALYSIS

This is a 26-week, double-blinded, randomised, placebo-controlled trial. Altogether, 104 patients diagnosed with a schizophrenia spectrum disorder, aged 18-65 years, with pre-diabetes or diabetes will be randomised to injections of 1.0 mg semaglutide once a week or placebo for 26 weeks. The primary endpoint is change from baseline in HbA1c. Secondary endpoints include changes in body weight, hip and waist circumference and plasma levels of insulin, glucagon, glucose, and C-peptide, insulin sensitivity, beta cell function, hepatic function, fibrosis-4 score, lipid profile, incretin hormones, bone markers, body composition, bone density, proteomic analyses and oxidative stress markers. Together with alcohol, tobacco and drug use, potential effects on the reward value of a sweet-fat stimulus, psychopathology, level of activity and quality of life will also be assessed.

ETHICS AND DISSEMINATION

This study is approved by the Danish Medicines Agency and the regional scientific ethics committee of the Capital Region of Denmark (committee C, #H-20019008) and will be carried out in accordance with International Council for Harmonisation Good Clinical Practice guidelines and the Helsinki Declaration. The results will be disseminated through peer-review publications and conference presentations.

TRIAL REGISTRATION NUMBER

NCT04892199.

MRI-Based Score for Assessment of Bone Mineral Density in Operative Spine Patients

STUDY DESIGN

Retrospective comparison.

OBJECTIVE

The aim was to determine whether a previously developed magnetic resonance imaging (MRI)-derived bone mineral density (BMD) scoring system can differentiate between healthy and osteoporotic vertebrae and to validate this scoring system against quantitative computed tomography measurements.

SUMMARY OF BACKGROUND DATA

BMD is an important preoperative consideration in spine surgery. Techniques to measure BMD are subject to falsely elevated values in the setting of spondylosis (dual-energy X-ray absorptiometry) or require significant exposure to radiation [quantitative computed tomography (QCT)]. Previous studies have shown that MRI may be utilized to measure bone quality using changes in the bone marrow signal observed on T1-weighted MRIs.

MATERIALS AND METHODS

Retrospective study of patients who underwent operative lumbar procedures at a single tertiary institution between 2016 and 2021 (n=61). Vertebral bone quality (VBQ) scores were measured by dividing the median signal intensities of L1-L4 by the signal intensity of cerebrospinal fluid on noncontrast T1W MRI. Demographic data, comorbidities, VBQ scores, and QCT-derived T scores and BMD of the lumbar spine were compared between healthy ( T score ≥-1; n=21), osteopenic (-2.5 < T score < -1; n=21), and osteoporotic ( T score ≤-2.5; n=19) cohorts using analysis of variance with post hoc Tukey test. Linear regression and receiver operating characteristic curve analyses were performed to assess the predictive value of VBQ scores. Pearson correlation test was used to evaluate the association between VBQ scores and QCT-derived measurements.

RESULTS

VBQ differentiated between healthy and osteoporotic groups ( P =0.009). Receiver operating characteristic curve analysis revealed that a greater VBQ score was associated with presence of osteoporosis (area under the curve=0.754, P =0.006). Cutoff VBQ for osteoporosis was 2.6 (Youden index 0.484; sensitivity: 58%; specificity: 90%). VBQ scores weakly correlated with QCT-derived BMD ( P =0.03, r =-0.27) and T scores ( P =0.04, r =-0.26).

CONCLUSION

This study attempted to further validate a previously developed MRI-based BMD scoring system against QCT-derived measurements. VBQ score was found to be a significant predictor of osteoporosis and could differentiate between healthy and osteoporotic vertebrae.

Emerging Role of 18F-NaF PET/Computed Tomographic Imaging in Osteoporosis: A Potential Upgrade to the Osteoporosis Toolbox

Osteoporosis is a metabolic bone disorder that leads to a decline in bone microarchitecture, predisposing individuals to catastrophic fractures. The current standard of care relies on detecting bone structural change; however, these methods largely miss the complex biologic forces that drive these structural changes and response to treatment. This review introduces sodium fluoride (18F-NaF) positron emission tomography/computed tomography (PET/CT) as a powerful tool to quantify bone metabolism. Here, we discuss the methods of 18F-NaF PET/CT, with a special focus on dynamic scans to quantify parameters relevant to bone health, and how these markers are relevant to osteoporosis.

The feasibility study of XACT imaging for characterizing osteoporosis

BACKGROUND

Osteoporosis is a progressive bone disease that is characterized by a decrease in bone mass and the deterioration in bone microarchitecture, which might be related to age and space travel. An unmet need exists for the development of novel imaging technologies to characterize osteoporosis.

PURPOSE

The purpose of our study is to investigate the feasibility of X-ray-induced acoustic computed tomography (XACT) imaging for osteoporosis detection.

METHODS

An in-house simulation workflow was developed to assess the ability of XACT for osteoporosis detection. To evaluate this simulation workflow, a three-dimensional digital bone phantom for XACT imaging was created by a series of two-dimensional micro-computed tomography (micro-CT) slices of normal and osteoporotic bones in mice. In XACT imaging, the initial acoustic pressure rise caused by the X-ray induce acoustic (XA) effect is proportional to bone density. First, region growing was deployed for image segmentation of different materials inside the bone. Then k-wave simulations were deployed to model XA wave propagation, attenuation, and detection. Finally, the time-varying pressure signals detected at each transducer location were used to reconstruct the XACT image with a time-reversal reconstruction algorithm.

RESULTS

Through the simulated XACT images, cortical porosity has been calculated, and XA signal spectra slopes have been analyzed for the detection of osteoporosis. The results have demonstrated that osteoporotic bones have lower bone mineral density and higher spectra slopes. These findings from XACT images were in good agreement with porosity calculation from micro-CT images.

CONCLUSION

This work explores the feasibility of using XACT imaging as a new imaging tool for Osteoporosis detection. Considering that acoustic signals are generated by X-ray absorption, XACT imaging can be combined with traditional X-ray imaging that holds potential for clinical management of osteoporosis and other bone diseases.

ACR Appropriateness Criteria® Osteoporosis and Bone Mineral Density: 2022 Update

Osteoporosis constitutes a significant public health risk. An estimated 10.2 million adults in the United States >50 years of age have osteoporosis, a systemic condition that weakens the bones increasing the susceptibility for fractures. Approximately one-half of women and nearly one-third of men >50 years of age will sustain an osteoporotic fracture. These fractures are associated with a decrease in quality of life, diminished physical function, and reduced independence. Dual-energy X-ray absorptiometry (DXA) is the primary imaging modality used to screen for osteoporosis in women >65 years of age and men >70 years of age. DXA may be used in patients <65 years of age to evaluate bone mass density if there are additional risk factors. In certain situations, vertebral fracture assessment and trabecular bone score may further predict fracture risk, particularly in patients who are not yet osteoporotic but are in the range of osteopenia. Quantitative CT is useful in patients with advanced degenerative changes in the spine. Given the proven efficacy of pharmacologic therapy, the role of imaging to appropriately identify and monitor high-risk individuals is critical in substantially reducing osteoporosis-associated morbidity and mortality, and reducing the considerable cost to the health care system. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

The use of quantitative ultrasound in a tertiary-level children hospital: role in the follow-up of chronically ill patients

PURPOSE

To evaluate the use of QUS for the bone status assessment in children cared because of a chronic disease such as: inherited metabolic disorder, kidney disease and endocrine defect and considered by the attending physician as at specific risk.

METHODS

QUS outputs were calculated for each disorder and compared to: sex, age, Tanner stage, Z-score for height, weight and BMI (body mass index).

RESULTS

One-hundred-sixty-eight subjects aged between 3.5 and 18 years met the inclusion criteria. The overall bone quality indexes were under the normal range in all the groups considered. Impairment of bone quality parameters was more evident in the group of patients with inherited metabolic disorders, in which 65% of patients in charge were studied by QUS. Older age and sexual development were associated with less pronounced bone quality impairment, as measured by QUS, in the vast majority of conditions. Overall, the diseases for which the prediction of outcome was the strongest were: hyperphenylalaninemia, nephrotic syndrome and insulin dependent diabetes mellitus.

CONCLUSIONS

QUS is capable to provide information on skeletal status in children. Initial evaluation by QUS may allow defining patients with chronic disorders who deserve further, more invasive diagnostic studies. Inherited metabolic disorders warrant specific attention and strict monitoring for their potential effect on bone.

Bone microstructure evaluated by TBS and HR-pQCT in Chinese adults with X-linked hypophosphatemia

X-linked hypophosphatemia (XLH) is the most common form of heritable hypophosphatemic rickets. Although generalized mineralization defects have been observed, elevated areal bone mineral density (aBMD) in the lumbar spine measured by dual-energy X-ray absorptiometry (DXA) has also been found in XLH. In contrast, high-resolution peripheral quantitative computed tomography (HR-pQCT) revealed lower volumetric BMD (vBMD) and damaged bone microstructure in the peripheral bone in XLH. Trabecular bone score (TBS), which can assess the trabecular microstructure in the lumbar spine, has not been explored in XLH. This study aimed to explore TBS and its correlations with biochemical indices and HR-pQCT parameters in adult XLH patients. A total of 66 patients with XLH (26 men and 40 women) aged 29.6 ± 9.6 years and 66 age- and sex-matched healthy controls were included. Z score of lumbar spine aBMD was relatively high [2.0 (0.6, 3.7)], with normal TBS (1.475 ± 0.129) in the XLH patients. HR-pQCT revealed larger total and trabecular area in the peripheral bone in the XLH group compared with the control group. In addition, lower trabecular and cortical vBMD, lower trabecular number with greater separation, and lower bone strength at both the radius and tibia were found in the XLH group compared with the control group. Smaller cortical area, lower thickness and higher porosity in the XLH group compared with controls were only found at the radius. TBS was not associated with any biochemical indices, while better HR-pQCT parameters correlated with higher serum phosphate and lower ALP levels. TBS was positively related with aBMD but not HR-pQCT parameters. In conclusion, adult patients with XLH had high bone mass and normal TBS in the lumbar spine but compromised microarchitecture and bone strength in the peripheral bone. This finding indicated a site-specific effect of the disease on the skeleton in the XLH patients.

Is it time to consider population screening for fracture risk in postmenopausal women? A position paper from the International Osteoporosis Foundation Epidemiology/Quality of Life Working Group

The IOF Epidemiology and Quality of Life Working Group has reviewed the potential role of population screening for high hip fracture risk against well-established criteria. The report concludes that such an approach should strongly be considered in many health care systems to reduce the burden of hip fractures.

INTRODUCTION

The burden of long-term osteoporosis management falls on primary care in most healthcare systems. However, a wide and stable treatment gap exists in many such settings; most of which appears to be secondary to a lack of awareness of fracture risk. Screening is a public health measure for the purpose of identifying individuals who are likely to benefit from further investigations and/or treatment to reduce the risk of a disease or its complications. The purpose of this report was to review the evidence for a potential screening programme to identify postmenopausal women at increased risk of hip fracture.

METHODS

The approach took well-established criteria for the development of a screening program, adapted by the UK National Screening Committee, and sought the opinion of 20 members of the International Osteoporosis Foundation's Working Group on Epidemiology and Quality of Life as to whether each criterion was met (yes, partial or no). For each criterion, the evidence base was then reviewed and summarized.

RESULTS AND CONCLUSION

The report concludes that evidence supports the proposal that screening for high fracture risk in primary care should strongly be considered for incorporation into many health care systems to reduce the burden of fractures, particularly hip fractures. The key remaining hurdles to overcome are engagement with primary care healthcare professionals, and the implementation of systems that facilitate and maintain the screening program.

Bone hydration: How we can evaluate it, what can it tell us, and is it an effective therapeutic target?

Water constitutes roughly a quarter of the cortical bone by volume yet can greatly influence mechanical properties and tissue quality. There is a growing appreciation for how water can dynamically change due to age, disease, and treatment. A key emerging area related to bone mechanical and tissue properties lies in differentiating the role of water in its four different compartments, including free/pore water, water loosely bound at the collagen/mineral interfaces, water tightly bound within collagen triple helices, and structural water within the mineral. This review summarizes our current knowledge of bone water across the four functional compartments and discusses how alterations in each compartment relate to mechanical changes. It provides an overview on the advent of- and improvements to- imaging and spectroscopic techniques able to probe nano-and molecular scales of bone water. These technical advances have led to an emerging understanding of how bone water changes in various conditions, of which aging, chronic kidney disease, diabetes, osteoporosis, and osteogenesis imperfecta are reviewed. Finally, it summarizes work focused on therapeutically targeting water to improve mechanical properties.

Cultural adaptation and psychometric assessment of the Persian version of the lumbar spine instability questionnaire

BACKGROUND

The Lumbar Spine Instability Questionnaire (LSIQ) is a self-reported measure of clinical instability of the lumbar spine. This study aimed to translate and culturally adapt the LSIQ into Persian language (LSIQ-P) and to evaluate its reliability and validity in a sample of patients with chronic non-specific low back pain (LBP).

METHODS

In a cross-sectional study, the LSIQ was translated using guidelines. Participants with chronic non-specific LBP, aged ≥ 18 years old, answered an online survey consisting of LSIQ-P, the Persian Functional Rating Index (FRI), and the pain Numeric Rating Scale (NRS). Construct validity, internal consistency reliability, test-retest reliability, standard error of measurement (SEM), smallest detectable change (SDC), discriminant validity, and factor analysis were evaluated.

RESULTS

The LSIQ was successfully adapted into Persian. A sample of 100 participants with LBP and 100 healthy subjects completed the survey. Floor and ceiling effects were not observed. Cronbach's alpha = 0.767 and ICC_agreement = 0.78 indicated good internal consistency and test-retest reliability. The SEM and SDC were 1.53 and 4.24, respectively. Construct validity of LSIQ-P was confirmed with significant correlation with Persian FRI (r = 0.44, p < 0.001) and pain NRS (r = 0.30, p = 0.003). An evidence of discriminant validity was demonstrated by significant difference in LSIQ-P total scores between the patients with LBP and healthy subjects, and between the patients with high total score ≥ 9 and those with low total score < 9 on the LSIQ-P. The LSIQ-P was found a multidimensional instrument with eight items appeared being redundant.

CONCLUSIONS

The Persian LSIQ showed satisfactory metric characteristics of reliability and validity. Further studies are required to elucidate the internal structure of the LSIQ-P.

Imaging of the Osteoporotic Spine - Quantitative Approaches in Diagnostics and for the Prediction of the Individual Fracture Risk

Osteoporosis is a highly prevalent systemic skeletal disease that is characterized by low bone mass and microarchitectural bone deterioration. It predisposes to fragility fractures that can occur at various sites of the skeleton, but vertebral fractures (VFs) have been shown to be particularly common. Prevention strategies and timely intervention depend on reliable diagnosis and prediction of the individual fracture risk, and dual-energy X-ray absorptiometry (DXA) has been the reference standard for decades. Yet, DXA has its inherent limitations, and other techniques have shown potential as viable add-on or even stand-alone options. Specifically, three-dimensional (3 D) imaging modalities, such as computed tomography (CT) and magnetic resonance imaging (MRI), are playing an increasing role. For CT, recent advances in medical image analysis now allow automatic vertebral segmentation and value extraction from single vertebral bodies using a deep-learning-based architecture that can be implemented in clinical practice. Regarding MRI, a variety of methods have been developed over recent years, including magnetic resonance spectroscopy (MRS) and chemical shift encoding-based water-fat MRI (CSE-MRI) that enable the extraction of a vertebral body's proton density fat fraction (PDFF) as a promising surrogate biomarker of bone health. Yet, imaging data from CT or MRI may be more efficiently used when combined with advanced analysis techniques such as texture analysis (TA; to provide spatially resolved assessments of vertebral body composition) or finite element analysis (FEA; to provide estimates of bone strength) to further improve fracture prediction. However, distinct and experimentally validated diagnostic criteria for osteoporosis based on CT- and MRI-derived measures have not yet been achieved, limiting broad transfer to clinical practice for these novel approaches. KEY POINTS::   · DXA is the reference standard for diagnosis and fracture prediction in osteoporosis, but it has important limitations.. · CT- and MRI-based methods are increasingly used as (opportunistic) approaches.. · For CT, particularly deep-learning-based automatic vertebral segmentation and value extraction seem promising.. · For MRI, multiple techniques including spectroscopy and chemical shift imaging are available to extract fat fractions.. · Texture and finite element analyses can provide additional measures for vertebral body composition and bone strength.. CITATION FORMAT: · Sollmann N, Kirschke JS, Kronthaler S et al. Imaging of the Osteoporotic Spine - Quantitative Approaches in Diagnostics and for the Prediction of the Individual Fracture Risk. Fortschr Röntgenstr 2022; DOI: 10.1055/a-1770-4626.

Official position of the Brazilian Association of Bone Assessment and Metabolism (ABRASSO) on the evaluation of body composition by densitometry: part I (technical aspects)—general concepts, indications, acquisition, and analysis

Objective

To review the technical aspects of body composition assessment by dual-energy X-ray absorptiometry (DXA) and other methods based on the most recent scientific evidence.

Materials and methods

This Official Position is a result of efforts by the Scientific Committee of the Brazilian Association of Bone Assessment and Metabolism (Associação Brasileira de Avaliação Óssea e Osteometabolismo, ABRASSO) and health care professionals with expertise in body composition assessment who were invited to contribute to the preparation of this document. The authors searched current databases for relevant publications. In this first part of the Official Position, the authors discuss the different methods and parameters used for body composition assessment, general principles of DXA, and aspects of the acquisition and analysis of DXA scans.

Conclusion

Considering aspects of accuracy, precision, cost, duration, and ability to evaluate all three compartments, DXA is considered the gold-standard method for body composition assessment, particularly for the evaluation of fat mass. In order to ensure reliable, adequate, and reproducible DXA reports, great attention is required regarding quality control procedures, preparation, removal of external artifacts, imaging acquisition, and data analysis and interpretation.

Should Q-CT Be the Gold Standard for Detecting Spinal Osteoporosis?

STUDY DESIGN

Prospective comparative study.

OBJECTIVE

Refinement of the guidelines for screening of osteoporosis and considering quantitative computed tomography (Q-CT) for detecting spinal osteoporosis.

SUMMARY OF BACKGROUND DATA

Spinal osteoporosis is often underestimated and under-evaluated due to either lack of availability of the diagnostic modality or lack of awareness about the possibility of overestimation by dual X-ray absorptiometry (DXA) scan. There is a need for reconsidering osteoporosis evaluation with a site specific and patient specific inclination.

METHODS

Post-menopausal women that underwent bone mineral density (BMD) evaluation from January-2018 to December-2020 with either Q-CT or DXA were evaluated. Comparison studies of the distribution of age and T-scores of the bone densities obtained from the two study groups: age-matched, sex-matched, and common skeletal site of interest (L1-4 vertebrae) were performed. Mann-Whitney U test, correlation and regression analyses were performed and bell curves were plotted.

RESULTS

Of the 718 women evaluated, 447 underwent Q-CT and 271 underwent DXA. There was no significant difference among the age distribution of the two study groups (P-value > 0.05). The mean and mode T-scores obtained by Q-CT and DXA were found to be -2.71, -3.8 and -1.63, -1.7 respectively. A highly significant difference in the T-scores was observed in the Q-CT and DXA groups (P-value < 0.0001). Among those who were screened by Q-CT, 58.16% were osteoporotic, 37.58% were osteopenic, and 4.25% were normal. The respective percentages in the DXA group were 30.63%, 49.82%, and 19.55%.

CONCLUSION

Q-CT provides more precise estimation of cancellous bone mineral density than DXA. With the reliance on DXA for spinal BMD estimation being questionable, new standards have to be established for spinal osteoporosis evaluation. Q-CT can be a better alternative to replace DXA as the gold standard for the evaluation of spinal osteoporosis.Level of Evidence: 2.

Automatic phantom-less QCT system with high precision of BMD measurement for osteoporosis screening: Technique optimisation and clinical validation

Background

Objective

Methods

Results

Conclusion

Translational potential statement

Dual Hip DXA. Is it Time to Change Standard Protocol?

Previous studies have examined the utility of bilateral DXA hip bone mineral density (BMD) scans. While most studies demonstrate an advantage of bilateral hip scanning, the studies have been limited by size, or have not included simultaneous lumbar spine scans. To analyse the utility of dual hip scans in a clinical environment, a large retrospective study was performed of DXA BMD of both hips, and lumbar spine, in 17,169 individuals assessed at one centre over 10 years. There was no clinically significant difference in the population mean femoral neck BMD of the left vs the right leg (0.878 vs 0.881g/cm2) or total proximal femoral BMD of the left vs the right leg (0.920 vs 0.919g/cm2). There were however discrepancies in individuals between hip t-scores. For the total hip 1,977 (11.5 %) and 147 (0.9 %) of subjects had absolute t score differences ≥ 0.50 or ≥ 1.00. respectively. For the femoral neck 3,320 (19.3%) and 337 (2.0%) of subjects had absolute t score differences ≥ 0.50 or ≥ 1.00. respectively. Of the total 17,169 individuals there were 2,776 subjects with osteoporosis (T≤ -2.5) using the lumbar spine and right hip, compared to 2,834 subjects using the lumbar spine and left hip. Using the lumbar spine and both hips identified 3,214 individuals with osteoporosis. Diagnosis based on use of the lumbar spine and right hip BMD, or lumbar spine and left hip BMD, therefore failed to identify 15.8%, or 13.4%, of osteoporotic subjects respectively. Additional scanning time required was assessed in 40 subjects prospectively. Performing lumbar spine and both hips, compared to lumbar spine and one hip, required an average additional scan time of 55 seconds. The recommendation of best practise for DXA BMD measurements should be reviewed to consider lumbar spine and dual hip DXA as standard of care.

Prospective comparative study of quantitative X-ray (QXR) versus dual energy X-ray absorptiometry to determine the performance of QXR as a predictor of bone health for adult patients in secondary care

OBJECTIVES

To evaluate a method of quantitative X-ray (QXR) for obtaining bone health information from standard radiographs aimed at identifying early signs of osteoporosis to enable improved referral and treatment. This QXR measurement is performed by postexposure analysis of standard radiographs, meaning bone health data can be acquired opportunistically, alongside routine imaging.

DESIGN

The relationship between QXR and dual energy X-ray absorptiometry (DEXA) was demonstrated with a phantom study. A prospective clinical study was conducted to establish areal bone mineral density (aBMD) prediction model and a risk prediction model of a non-normal DEXA outcome. This was then extrapolated to a larger patient group with DEXA referral data.

SETTING

Secondary care National Health Service Hospital.

PARTICIPANTS

126 consenting adult patients from a DEXA clinic.

INTERVENTIONS

All participants underwent a DEXA scan to determine BMD at the lumbar spine (L2-L4) and both hips. An additional Antero-Posterior pelvis X-ray on a Siemens Ysio, fixed digital radiograph system was performed for the study.

OUTCOME

Performance of QXR as a risk predictor for non-normal (osteoporotic) BMD.

RESULTS

Interim clinical study data from 78 patients confirmed a receiver operator curve (area under the ROC curve) of 0.893 (95% CI 0.843 to 0.942) for a risk prediction model of non-normal DEXA outcome. Extrapolation of these results to a larger patient group of 11 029 patients indicated a positive predictive value of 0.98 (sensitivity of 0.8) for a population of patients referred to DEXA under current clinical referral criteria.

CONCLUSIONS

This study confirms that the novel QXR method provides accurate prediction of a DEXA outcome.

TRIAL REGISTRATION NUMBER

ISRCTN98160454; Pre-results.

Effects of a Home-Based Exercise Intervention (E-Fit) on Bone Density, Muscle Function, and Quality of Life in Girls with Adolescent Idiopathic Scoliosis (AIS): A Pilot Randomized Controlled Trial

Background: Adolescent idiopathic scoliosis (AIS) patients have lower physical activity levels than normal adolescents, and there is an association with poorer bone and muscle health. This study evaluated the effects of a home-based exercise intervention (E-Fit) on bone mineral density (BMD), muscle function, and quality of life (QoL) in AIS-affected girls. Methods: A total of 40 AIS females aged 11 to 14 years were randomly assigned to the E-Fit or control group. The E-Fit group performed modified 7-min high-intensity interval training (HIIT) 5 days per week for 6 months. Outcome measures including BMD using dual-energy X-ray absorptiometry (DXA), muscle strength and endurance tests, physical activity levels, and QoL using self-reported questionnaires were assessed at baseline and at 6-month and 12-month follow-up. Results: In total, 14 patients in the E-Fit and 16 in the control group completed the study. The E-Fit group showed a marginally significant interaction effect in the whole body areal BMD at the 6- (p = 0.096) and 12-month follow-ups (p = 0.085). The left arm lean mass in the E-Fit group showed a statistically significant interaction effect between the 6- and 12-month follow-ups (p = 0.046). The E-Fit group showed improvements in physical activity participation, as measured by the Modified Baecke Questionnaire (MBQ), with a significant interaction effect in work index (p = 0.043), sport index (p = 0.050), and total score (p = 0.016) from baseline to the 12-month follow-up. Improvement on self-image were noted in E-Fit group across time. Conclusions: The present results provided some evidence to support the positive benefits of E-Fit for bone health and muscle function in AIS girls.

Types of vertebral fractures could influence the selection of clinical bone mineral measures to predict biomechanical properties

Areal and volumetric BMD (aBMD and vBMD) measured by DXA and quantitative CT (QCT), respectively, are usually employed to predict vertebral fracture risks. In this study, we induced compression and wedge vertebral fractures to test if the types of fracture could influence the selection of bone mineral measures to predict biomechanical properties of vertebral bodies. DXA and QCT were employed to scan twenty-four male cadaveric vertebral bodies of humans for bone mineral content (BMC) and aBMD measures, and vBMD measures, respectively. We computed vBMD measures from three kinds of volumes of interest: intact structures (vertebral body, cortical compartment, and trabecular core), axially middle sections (1.250-1.875 cm height) of the intact structures, and clinically used elliptical regions of trabecular bone. We loaded vertebral bodies to failure for properties of strength (P_u), failure displacement (δ_u), and stiffness (K). Thirteen vertebral bodies sustained compression fractures and the remaining sustained wedge fractures. Linear and power regression models were used to test bone mineral predictions for P_u, δ_u, and K. We also did equality tests of correlation coefficients. Our results showed aBMD, BMC, and vBMD of the middle section of trabecular bone had the strongest correlations with P_u (R² = 0.6420, p < 0.001), δ_u (R² = 0.4619, p < 0.001), and K (R² = 0.5992, p < 0.001) in power regression models, respectively when compression and wedge fractures were mixed. Considering compression fractures only, vBMD of the intact vertebral body displayed the strongest correlations with both P_u (R² = 0.6529, p < 0.001) and K (R² = 0.6354, p < 0.001) while BMC showed the strongest correlation with δ_u (R² = 0.4376, p < 0.001) in linear regression models. When only wedge fractures were analyzed, vBMD of the elliptical regions of trabecular bone exhibited the strongest correlations with both P_u (R² = 0.5845, p < 0.001) and K (R² = 0.6420, p < 0.001) in power regression models, however, no bone mineral measure could significantly correlate with δ_u. These results may suggest the type of fracture could influence the determination of bone mineral measures to predict biomechanical properties of vertebral bodies.

Accuracy and precision of volumetric bone mineral density assessment using dual-source dual-energy versus quantitative CT: a phantom study

Background

Dual-source dual-energy computed tomography (DECT) offers the potential for opportunistic osteoporosis screening by enabling phantomless bone mineral density (BMD) quantification. This study sought to assess the accuracy and precision of volumetric BMD measurement using dual-source DECT in comparison to quantitative CT (QCT).

Methods

A validated spine phantom consisting of three lumbar vertebra equivalents with 50 (L1), 100 (L2), and 200 mg/cm³ (L3) calcium hydroxyapatite (HA) concentrations was scanned employing third-generation dual-source DECT and QCT. While BMD assessment based on QCT required an additional standardised bone density calibration phantom, the DECT technique operated by using a dedicated postprocessing software based on material decomposition without requiring calibration phantoms. Accuracy and precision of both modalities were compared by calculating measurement errors. In addition, correlation and agreement analyses were performed using Pearson correlation, linear regression, and Bland-Altman plots.

Results

DECT-derived BMD values differed significantly from those obtained by QCT (p < 0.001) and were found to be closer to true HA concentrations. Relative measurement errors were significantly smaller for DECT in comparison to QCT (L1, 0.94% versus 9.68%; L2, 0.28% versus 5.74%; L3, 0.24% versus 3.67%, respectively). DECT demonstrated better BMD measurement repeatability compared to QCT (coefficient of variance < 4.29% for DECT, < 6.74% for QCT). Both methods correlated well to each other (r = 0.9993; 95% confidence interval 0.9984–0.9997; p < 0.001) and revealed substantial agreement in Bland-Altman plots.

Conclusions

Phantomless dual-source DECT-based BMD assessment of lumbar vertebra equivalents using material decomposition showed higher diagnostic accuracy compared to QCT.

Validation and Optimization of Proximal Femurs Microstructure Analysis Using High Field and Ultra-High Field MRI

Trabecular bone could be assessed non-invasively using MRI. However, MRI does not yet provide resolutions lower than trabecular thickness and a comparative analysis between different MRI sequences at different field strengths and X-ray microtomography (μCT) is still missing. In this study, we compared bone microstructure parameters and bone mineral density (BMD) computed using various MRI approaches, i.e., turbo spin echo (TSE) and gradient recalled echo (GRE) images used at different magnetic fields, i.e., 7T and 3T. The corresponding parameters computed from μCT images and BMD derived from dual-energy X-ray absorptiometry (DXA) were used as the ground truth. The correlation between morphological parameters, BMD and fracture load assessed by mechanical compression tests was evaluated. Histomorphometric parameters showed a good agreement between 7T TSE and μCT, with 8% error for trabecular thickness with no significative statistical difference and a good intraclass correlation coefficient (ICC > 0.5) for all the extrapolated parameters. No correlation was found between DXA-BMD and all morphological parameters, except for trabecular interconnectivity (R2 > 0.69). Good correlation (p-value < 0.05) was found between failure load and trabecular interconnectivity (R2 > 0.79). These results suggest that MRI could be of interest for bone microstructure assessment. Moreover, the combination of morphological parameters and BMD could provide a more comprehensive view of bone quality.

"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 mineral density surveillance for childhood, adolescent, and young adult cancer survivors: evidence-based recommendations from the International Late Effects of Childhood Cancer Guideline Harmonization Group

Childhood, adolescent, and young adult cancer survivors are at increased risk of reduced bone mineral density. Clinical practice surveillance guidelines are important for timely diagnosis and treatment of these survivors, which could improve bone mineral density parameters and prevent fragility fractures. Discordances across current late effects guidelines necessitated international harmonisation of recommendations for bone mineral density surveillance. The International Late Effects of Childhood Cancer Guideline Harmonization Group therefore established a panel of 36 experts from ten countries, representing a range of relevant medical specialties. The evidence of risk factors for very low and low bone mineral density and fractures, surveillance modality, timing of bone mineral density surveillance, and treatment of very low and low bone mineral density were evaluated and critically appraised, and harmonised recommendations for childhood, adolescent, and young adult cancer survivors were formulated. We graded the recommendations based on the quality of evidence and balance between potential benefits and harms. Bone mineral density surveillance is recommended for survivors treated with cranial or craniospinal radiotherapy and is reasonable for survivors treated with total body irradiation. Due to insufficient evidence, no recommendation can be formulated for or against bone mineral density surveillance for survivors treated with corticosteroids. This surveillance decision should be made by the survivor and health-care provider together, after careful consideration of the potential harms and benefits and additional risk factors. We recommend to carry out bone mineral density surveillance using dual-energy x-ray absorptiometry at entry into long-term follow-up, and if normal (Z-score > -1), repeat when the survivor is aged 25 years. Between these measurements and thereafter, surveillance should be done as clinically indicated. These recommendations facilitate evidence-based care for childhood, adolescent, and young adult cancer survivors internationally.

Operator-Related Errors and Pitfalls in Dual Energy X-Ray Absorptiometry: How to Recognize and Avoid Them

Dual-energy X-ray absorptiometry (DXA) is the most common modality for quantitative measurements of bone mineral density. Nevertheless, errors related to this exam are still very common, and may significantly impact on the final diagnosis and therapy. Operator-related errors may occur during each DXA step and can be related to wrong patient positioning, error in the acquisition process or in the scan analysis. The aim of this review is to provide a practical guide on how to recognize such errors in spine and hip DXA scan and how to avoid them, also presenting some of the most common artifacts encountered in clinical practice.

Radiographic diagnosis of osteoporotic vertebral fractures. An updated review

The radiological diagnosis of osteoporotic vertebral fractures (OVFs) is of major importance considering its therapeutic and prognostic implications. Both radiologists and clinicians have the opportunity to diagnose OVFs in daily clinical practice due to the widespread use of spine and chest radiography. However, several studies have reported an under-diagnosis of OVFs, particularly by a lack of consensus on the diagnostic criteria. Therefore, up-to-date knowledge of the most relevant approaches for the diagnosis of OVFs is necessary for many physicians. This article aims to review the most commonly used classification systems in the diagnosis of OVFs based on conventional radiography. We discuss their rationale, advantages and limitations, as well as their utility according to the context. This review will provide a concise yet useful understanding of the typology of OVFs, their clinical significance and prognosis. Finally, we include anatomical variations that can be confused with OVFs by non-experts.

Survey of MRI Usefulness for the Clinical Assessment of Bone Microstructure

Bone microarchitecture has been shown to provide useful information regarding the evaluation of skeleton quality with an added value to areal bone mineral density, which can be used for the diagnosis of several bone diseases. Bone mineral density estimated from dual-energy X-ray absorptiometry (DXA) has shown to be a limited tool to identify patients’ risk stratification and therapy delivery. Magnetic resonance imaging (MRI) has been proposed as another technique to assess bone quality and fracture risk by evaluating the bone structure and microarchitecture. To date, MRI is the only completely non-invasive and non-ionizing imaging modality that can assess both cortical and trabecular bone in vivo. In this review article, we reported a survey regarding the clinically relevant information MRI could provide for the assessment of the inner trabecular morphology of different bone segments. The last section will be devoted to the upcoming MRI applications (MR spectroscopy and chemical shift encoding MRI, solid state MRI and quantitative susceptibility mapping), which could provide additional biomarkers for the assessment of bone microarchitecture.