Prevalence and type of errors in dual-energy x-ray absorptiometry

Unsupervised domain adaptation based on feature and edge alignment for femur X-ray image segmentation

The gold standard for diagnosing osteoporosis is bone mineral density (BMD) measurement by dual-energy X-ray absorptiometry (DXA). However, various factors during the imaging process cause domain shifts in DXA images, which lead to incorrect bone segmentation. Research shows that poor bone segmentation is one of the prime reasons of inaccurate BMD measurement, severely affecting the diagnosis and treatment plans for osteoporosis. In this paper, we propose a Multi-feature Joint Discriminative Domain Adaptation (MDDA) framework to improve segmentation performance and the generalization of the network in domain-shifted images. The proposed method learns domain-invariant features between the source and target domains from the perspectives of multi-scale features and edges, and is evaluated on real data from multi-center datasets. Compared to other state-of-the-art methods, the feature prior from the source domain and edge prior enable the proposed MDDA to achieve the optimal domain adaptation performance and generalization. It also demonstrates superior performance in domain adaptation tasks on small amount datasets, even using only 5 or 10 images. In this study, MDDA provides an accurate bone segmentation tool for BMD measurement based on DXA imaging.

Assessing osteoporosis in postmenopausal women: preliminary results using a novel lumbar spine phantom-based MRI scoring method

OBJECTIVE

To develop a novel magnetic resonance imaging (MRI) phantom for producing F-score (for fat) and W-score (for water) and to evaluate the performance of these scores in assessing osteoporosis and related vertebral fractures.

MATERIALS AND METHODS

First, a real-time phantom consisting of oil and water tubes was manufactured. Then, 30 female volunteers (age: 62.3 ± 6.3 years) underwent lumbar spine examination with MRI (using a novel phantom) and dual-energy X-ray absorptiometry (DXA), following ethical approval. MRI phantom-based F-score and W-score were defined by normalizing the vertebral signal intensities (SIs) by the oil and water SIs of the phantom on T1- and T2-weighted images, respectively. The diagnostic performances of the new scores for assessing osteoporosis and vertebral fractures were examined using receiver operating characteristic analysis and compared with DXA-measured areal bone mineral density (DXA-aBMD).

RESULTS

The F-score and W-score were greater in the osteoporotic patients (3.93 and 2.29) than the non-osteoporotic subjects (3.05 and 1.79) and achieved AUC values of 0.85 and 0.74 (p < 0.05), respectively, when detecting osteoporosis. Similarly, F-score and W-score had greater values for the fracture patients (3.94 and 2.53) than the non-fracture subjects (3.14 and 1.69) and produced better AUC values (0.90 for W-score and 0.79 for F-score) compared to DXA-aBMD (AUC: 0.27, p < 0.05). In addition, the F-score and W-score had a strong correlation (r = 0.77; p < 0.001).

CONCLUSION

A novel real-time lumber spine MRI phantom was developed, based upon which newly defined F-score and W-score were able to detect osteoporosis and demonstrated an improved ability over DXA-aBMD in differentiating patients with vertebral fractures.

Bone health status evaluation in men by means of REMS technology

BACKGROUND

Osteoporosis in males is largely under-diagnosed and under-treated, with most of the diagnosis confirmed only after an osteoporotic fracture. Therefore, there is an urgent need for highly accurate and precise technologies capable of identifying osteoporosis earlier, thereby avoiding complications from fragility fractures.

AIMS

This study aimed to evaluate the diagnostic accuracy and precision of the non-ionizing technology Radiofrequency Echographic Multi Spectrometry (REMS) for the diagnosis of osteoporosis in a male population in comparison with conventional Dual-energy X-ray Absorptiometry (DXA).

METHODS

A cohort of 603 Caucasian males aged between 30 and 90 years were involved in the study. All the enrolled patients underwent lumbar and femoral scans with both DXA and REMS. The diagnostic agreement between REMS and DXA-measured BMD was expressed by Pearson correlation coefficient and Bland-Altman method. The accuracy of the diagnostic classification was evaluated by the assessment of sensitivity and specificity considering DXA as reference.

RESULTS

A significant correlation between REMS- and DXA-measured T-score values (r = 0.91, p < 0.0001) for lumbar spine and for femoral neck (r = 0.90, p < 0.0001) documented the substantial equivalence of the two measurement techniques. Bland-Altman outcomes showed that the average difference in T-score measurement is very close to zero (-0.06 ± 0.60 g/cm2 for lumbar spine and - 0.07 ± 0.44 g/cm2 for femoral neck) confirming the agreement between the two techniques. Furthermore, REMS resulted an effective technique to discriminate osteoporotic patients from the non-osteoporotic ones on both lumbar spine (sensitivity = 90.1%, specificity = 93.6%) and femoral neck (sensitivity = 90.9%, specificity = 94.6%). Precision yielded RMS-CV = 0.40% for spine and RMS-CV = 0.34% for femur.

CONCLUSION

REMS, is a reliable technology for the diagnosis of osteoporosis also in men. This evidence corroborates its high diagnostic performance already observed in previous studies involving female populations.

Bone densitometry in Thalassemia major: a closer look at pitfalls and operator-related errors in a 10-year follow-up population

PURPOSE

Dual-energy X-ray absorptiometry (DXA) is the gold standard for measuring bone mineral density (BMD) with tolerable error rate, high precision, and excellent consistency. Our objective was to investigate the frequency and distribution of errors in a cohort of patients with Thalassemia major (TM).

METHODS

We reviewed the DXA examinations of 340 patients with β-TM followed by our institution, acquired in different imaging centers between 2009 and 2019. We collected sex and age at the time of the first examination and at the last visit, as well as BMD, T-score, and Z-score values. Errors were analyzed by anatomical site (lumbar spine, total hip, femoral neck).

RESULTS

Out of 5099 total DXA scans, 11.85% presented one or more errors. Specifically, the incorrect examinations were 315 out of 1707 (18.45%) at the lumbar spine level, 113 out of 1697 (6.66%) at the total hip, 176 out of 1695 (10.38%) at the femoral neck. Errors in vertebral inclusion were the most frequently registered (45.86%). A significant difference resulted from the comparison of the T-score and Z-score median values of all the lumbar spine DXA examinations and the correct ones (p value 0.037 and 0.0003, respectively).

CONCLUSION

Although not directly involved in the performance and interpretation of DXA, physicians interested in osteoporosis management should be familiar with the protocols to minimize errors and allow the proper use of bone densitometry. DXA obtained at the spine level is more frequently affected by errors in patients with TM, potentially influencing the diagnostic assessment of bone health status.

Effect of exercise-induced body fluid redistribution on body composition in males using dual energy X-ray absorptiometry

We studied the effect of exercise-induced body fluid redistribution on dual-energy x-ray absorptiometry (DXA) body composition scores. Thirty males completed 30-min of upper-body exercise (UBE), lower-body exercise, and seated non-exercise control (NEC). ANOVA determined interactions between experimental conditions and measurements on body composition variables. For UBE, mean pre to post differences were found on tissue fat (M = 0.35 ± 0.12%; CI95%diff = 0.10 to 0.59%; p = 0.007), region fat (M = 0.32 ± 0.11%; CI95%diff = 0.09 to 0.55%; p = 0.008), lean mass (M = 0.27 ± 0.01 kg; CI95%diff = 0.18 to 0.37 kg; p ≤ 0.0001), and total mass (M = 0.27 ± 0.05 kg; CI95%diff = 0.17 to 0.36 kg; p ≤ 0.0001). Mean tissue pre to post differences were found for the total body in the NEC (M = 0.10 ± 0.04 kg; CI95%diff = 0.03 to 0.18 kg; p = 0.008), UBE (M = 0.19 ± 0.03 kg; CI95%diff = 0.14 to 0.24 kg; p ≤ 0.0001), and LBE (M = 0.31 ± 0.04 kg; CI95%diff = 0.24 to 0.39 kg; p ≤ 0.0001) conditions. High absolute reliability was found within experimental conditions. These findings have practical implications for technicians, since acute exercise elicited small changes in body composition scores using DXA.

The Effect of a Compression Bandage on Dual Energy X-ray Absorptiometry Body Composition Scores

BACKGROUND

Dual-energy X-ray absorptiometry (DXA) measures are affected by the noise produced by external factors such as textile compression found in loose clothing. The study aimed to determine the effect of a compression bandage (CB) on body composition (BC) assessed by DXA.

METHODS

Sixty volunteers (age=21.4±4.7yr.) underwent full-body DXA scans on a control (CTRL) condition and after wearing a 30-mmHg CB on the trunk, legs, and arms. ANOVA (2 genders by 2 experimental conditions) determined mean interactions in BC variables tissue body fat% (BF%), region body fat% (RBF%), body tissue (BT), fat mass (FM), lean mass (LM), bone mineral content (BMC), and total mass (TM). Absolute reliability in BC scores was studied by the typical error of the measurement (TEM), the coefficient of variability (CV), and Bland-Altman plots.

RESULTS

ANOVA interactions were found on tissue total BF% (p=0.049), RBF% (p=0.048), android lean mass (p=0.004), and android total mass (p=0.019). The CV was small for tissue BF% (2.61±0.93%, CI95%=0.79, 4.43%), RBF% (2.66±1.78%, CI95%=-0.83, 6.15%), BT (4.82±2.19%, CI95%=0.54, 9.10kg), FM (4.17±2.25%, CI95%=-0.24, 8.58kg), LM (3.25±2.44%, CI95%=-1.53, 8.04kg), BMC (4.81±2.96%, CI95%=-0.99, 10.62kg), and TM (2.84±2.80%, CI95%=-2.65, 8.33kg). Bland-Altman plots showed random error for BF%, LM, and BMC. A bias of 0.5% was observed on BF% in males.

CONCLUSION

A CB worn during a full-body DXA scan elicited similar BC scores than not wearing it. The variation in scores was <10% for most BC variables, and a trivial bias of 0.5% in BF% was detected in male scores.

DXA Reporting Updates: 2023 Official Positions of the International Society for Clinical Densitometry

INTRODUCTION

Professional guidance and standards assist radiologic interpreters in generating high quality reports. Initially DXA reporting Official Positions were provided by the ISCD in 2003; however, as the field has progressed, some of the current recommendations require revision and updating. This manuscript details the research approach and provides updated DXA reporting guidance.

METHODS

Key Questions were proposed by ISCD established protocols and approved by the Position Development Conference Steering Committee. Literature related to each question was accumulated by searching PubMed, and existing guidelines from other organizations were extracted from websites. Modifications and additions to the ISCD Official Positions were determined by an expert panel after reviewing the Task Force proposals and position papers.

RESULTS

Since most DXA is now performed in radiology departments, an approach was endorsed that better aligns with standard radiologic reports. To achieve this, reporting elements were divided into required minimum or optional. Collectively, required components comprise a standard diagnostic report and are considered the minimum necessary to generate an acceptable report. Additional elements were retained and categorized as optional. These optional components were considered relevant but tailored to a consultative, clinically oriented report. Although this information is beneficial, not all interpreters have access to sufficient clinical information, or may not have the clinical expertise to expand beyond a diagnostic report. Consequently, these are not required for an acceptable report.

CONCLUSION

These updated ISCD positions conform with the DXA field's evolution over the past 20 years. Specifically, a basic diagnostic report better aligns with radiology standards, and additional elements (which are valued by treating clinicians) remain acceptable but are optional and not required. Additionally, reporting guidance for newer elements such as fracture risk assessment are incorporated. It is our expectation that these updated Official Positions will improve compliance with required standards and generate high quality DXA reports that are valuable to the recipient clinician and contribute to best patient care.

National Survey of the Bone Densitometry Evaluation Process Within an Integrated Healthcare System

BACKGROUND

To assess the current state of bone mineral density evaluation services via dual energy x-ray absorptiometry (DXA) provided to Veterans with fracture risk through the development and administration of a nationwide survey of facilities in the Veterans Health Administration.

METHODOLOGY

The Bone Densitometry Survey was developed by convening a Work Group of individuals with expertise in bone densitometry and engaging the Work Group in an iterative drafting and revision process. Once completed, the survey was beta tested, administered through REDCap, and sent via e-mail to points of contact at 178 VHA facilities.

RESULTS

Facility response rate was 31 % (56/178). Most DXA centers reported positively to markers of readiness for their bone densitometers: less than 10 years old (n=35; 63 %); in "excellent" or "good" condition (n=44; 78 %, 32 % and 46 %, respectively); and perform phantom calibration (n=43; 77 %). Forty-one DXA centers (73 %) use intake processes that have been shown to reduce errors. Thirty-seven DXA centers (66 %) reported their technologists receive specialized training in DXA, while 14 (25 %) indicated they receive accredited training. Seventeen DXA centers (30 %) reported performing routine precision assessment.

CONCLUSIONS

Many DXA centers reported using practices that meet minimal standards for DXA reporting and preparation; however, the lack of standardization, even within an integrated healthcare system, indicates an opportunity for quality improvement to ensure consistent high quality bone mineral density evaluation of Veterans.

Dual-energy X-ray Absorptiometry Trends Among US Medicare Beneficiaries: 2005-2019

INTRODUCTION

Bone density measured using dual-energy X-ray absorptiometry (DXA) volume, performance site and interpreters have changed in the US since 2005. The purpose of this report is to provide updated trends in DXA counts, rates, place of service and interpreter specialty for the Medicare fee-for-service population.

METHODS

The 100 % Medicare Physician/Supplier Procedure Summary Limited Data Set between 2005-2019 was used. DXA counts and annual rates per 10,000 Medicare beneficiaries were calculated. Annual distributions of scan performance location, provider type and interpreter specialty were described. Place of service trends (significance assigned at p < 0.05) of the mean annual share of DXA utilization were identified using linear regression.

RESULTS

Annual DXA use per 10,000 beneficiaries peaked in 2008 at 832, declined to 656 in 2015 then increased (p < 0.001) by 38 per year to 807 in 2019. From 2005 to 2019 DXA performance in office settings declined from 70.7 % to 47.2 %. Concurrently, outpatient hospital (OH) DXA increased from 28.6 % to 51.7 %. In 2005, 43.5 % of DXAs were interpreted by radiologists. This increased (p < 0.001) in the office and OH, averaging 0.3 and 2.0 percentage points per year respectively, reaching 73.5 % in 2019. Interpretation by most non-radiologist specialties declined (p < 0.001).

CONCLUSIONS

From 2005-2019, total DXA use among Medicare beneficiaries declined reaching a nadir in 2015 then returned to 2005 levels by 2019. Office DXA declined since 2005 with 51.7 % of all scans now occurring in an OH setting. The proportion of DXAs interpreted by radiologists increased over time, reaching 73.5 % in 2019.

Identification of biomarkers associated with diagnosis of postmenopausal osteoporosis patients based on bioinformatics and machine learning

Background: Accumulating evidence suggests that postmenopausal osteoporosis (PMOP) is a common chronic systemic metabolic bone disease, but its specific molecular pathogenesis remains unclear. This study aimed to identify novel genetic diagnostic markers for PMOP. Methods: In this paper, we combined three GEO datasets to identify differentially expressed genes (DEGs) and performed functional enrichment analysis of PMOP-related differential genes. Key genes were analyzed using two machine learning algorithms, namely, LASSO and the Gaussian mixture model, and candidate biomarkers were found after taking the intersection. After further ceRNA network construction, methylation analysis, and immune infiltration analysis, ACACB and WWP1 were finally selected as diagnostic markers. Twenty-four clinical samples were collected, and the expression levels of biomarkers in PMOP were detected by qPCR. Results: We identified 34 differential genes in PMOP. DEG enrichment was mainly related to amino acid synthesis, inflammatory response, and apoptosis. The ceRNA network construction found that XIST-hsa-miR-15a-5p/hsa-miR-15b-5p/hsa-miR-497-5p and hsa-miR-195-5p-WWP1/ACACB may be RNA regulatory pathways regulating PMOP disease progression. ACACB and WWP1 were identified as diagnostic genes for PMOP, and validated in datasets and clinical sample experiments. In addition, these two genes were also significantly associated with immune cells, such as T, B, and NK cells. Conclusion: Overall, we identified two vital diagnostic genes responsible for PMOP. The results may help provide potential immunotherapeutic targets for PMOP.

Short-Term Precision and Repeatability of Radiofrequency Echographic Multi Spectrometry (REMS) on Lumbar Spine and Proximal Femur: An In Vivo Study

To determine the short-term intra-operator precision and inter-operator repeatability of radiofrequency echographic multi-spectrometry (REMS) at the lumbar spine (LS) and proximal femur (FEM). All patients underwent an ultrasound scan of the LS and FEM. Both precision and repeatability, expressed as root-mean-square coefficient of variation (RMS-CV) and least significant change (LSC) were obtained using data from two consecutive REMS acquisitions by the same operator or two different operators, respectively. The precision was also assessed in the cohort stratified according to BMI classification. The mean (±SD) age of our subjects was 48.9 ± 6.8 for LS and 48.3 ± 6.1 for FEM. Precision was assessed on 42 subjects at LS and 37 subjects on FEM. Mean (±SD) BMI was 24.71 ± 4.2 for LS and 25.0 ± 4.84 for FEM. Respectively, the intra-operator precision error (RMS-CV) and LSC resulted in 0.47% and 1.29% at the spine and 0.32% and 0.89% at the proximal femur evaluation. The inter-operator variability investigated at the LS yielded an RMS-CV error of 0.55% and LSC of 1.52%, whereas for the FEM, the RMS-CV was 0.51% and the LSC was 1.40%. Similar values were found when subjects were divided into BMI subgroups. REMS technique provides a precise estimation of the US-BMD independent of subjects' BMI differences.

Radiofrequency Echographic Multi Spectrometry (R.E.M.S.): New Frontiers for Ultrasound Use in the Assessment of Bone Status-A Current Picture

Osteoporosis is a frequently occurring skeletal disease, and osteoporosis-related fractures represent a significant burden for healthcare systems. Dual-Energy X-ray Absorptiometry (DXA) is the most commonly used method for assessing bone mineral density (BMD). Today, particular attention is being directed towards new technologies, especially those that do not use radiation, for the early diagnosis of altered bone status. Radiofrequency Echographic Multi Spectrometry (REMS) is a non-ionizing technology that evaluates the bone status at axial skeletal sites by analyzing raw ultrasound signals. In this review, we evaluated the data on the REMS technique present in the literature. The literature data confirmed diagnostic concordance between BMD values obtained using DXA and REMS. Furthermore, REMS has adequate precision and repeatability characteristics, is able to predict the risk of fragility fractures, and may be able to overcome some of the limitations of DXA. In conclusion, REMS could become the method of choice for the assessment of bone status in children, in women of childbearing age or who are pregnant, and in several secondary osteoporosis conditions due to its good precision and replicability, its transportability, and the absence of ionizing radiation. Finally, REMS may allow qualitative and not just quantitative assessments of bone status.

Advancement in the Treatment of Osteoporosis and the Effects on Bone Healing

Osteoporosis (OP) is a major global health concern, with aging being one of the most important risk factors. Osteoarthritis (OA) is also an age-related disorder. Patients with OP and/or OA may be treated surgically for fractures or when their quality of life is impaired. Poor bone quality due to OP can seriously complicate the stability of a bone fixation construct and/or surgical fracture treatment. This review summarizes the current knowledge on the pathophysiology of normal and osteoporotic bone healing, the effect of a bone fracture on bone turnover markers, the diagnosis of a low bone mineral density (BMD) before surgical intervention, and the effect of available anti-osteoporosis treatment. Interventions that improve bone health may enhance the probability of favorable surgical outcomes. Fracture healing and the treatment of atypical femoral fractures are also discussed.

Dual-energy x-ray absorptiometry scanner mismatch in follow-up bone mineral density testing

Scanner mismatch occurs frequently with follow-up dual-energy x-ray absorptiometry (DXA) scans. Nearly one-in-five follow-up DXA scans were conducted on non-cross-calibrated scanners (scanner mismatch) and more than a quarter of patients who had a follow-up DXA scan had experienced scanner mismatch.

INTRODUCTION

Detecting significant changes in bone mineral density (BMD) with dual-energy x-ray absorptiometry (DXA) scanners relies on the least significant change (LSC). Results from two different DXA scanners can only be compared, albeit with decreased sensitivity for change, if the LSC between the two scanners has been directly determined through cross-calibration. Performing follow-up DXA scans on non-cross-calibrated scanners (scanner mismatch) has safety and economic implications. This study aims to determine the proportion of scanner mismatch occurring at a population level.

METHODS

All patients who completed at least two DXA scans between 1 April 2009 and 31 December 2018 in the province of Alberta, Canada, were identified using population-based health services databases. Scanner mismatch was defined as a follow-up DXA scan completed on a DXA scanner that differed from and was not cross-calibrated to the previous DXA scanner. Multivariate logistic regression models were used to assess predictive factors that may contribute to scanner mismatch.

RESULTS

A total of 264,866 patients with 470,641 follow-up DXA scans were identified. Scanner mismatch occurred in 18.9% of follow-up DXA scans; 28.7% of patients experienced at least one scanner mismatch. Longer duration between scans (OR 1.25, 95% CI 1.24-1.26) and major osteoporotic fracture history before index scan (OR 1.06, 95% CI 1.03-1.08) increased risk of scanner mismatch. Osteoporosis medication use before index scan (OR 0.89; 95% CI 0.88-0.91), recency of follow-up scans (OR 0.98, 95% CI 0.73-0.98), female sex (OR 0.97, 95% CI 0.94-1.00), and age at last scan (OR 0.99, 95% CI 0.99-1.00) were associated with lower risk of scanner mismatch.

CONCLUSION

Scanner mismatch is a common problem, occurring in one-in-five follow-up DXA scans and affecting more than a quarter of patients. Interventions to reduce this large proportion of scanner mismatch are necessary.

The fracture predictive ability of lumbar spine BMD and TBS as calculated based on different combinations of the lumbar spine vertebrae

Lumbar spine bone mineral density (BMD) and trabecular bone score (TBS) are both calculated on L1-L4 vertebrae. This study investigated the ability to predict osteoporotic fractures of BMD and TBS as calculated based on all possible adjacent L1-L4 vertebrae combinations. Present findings indicate that L1-L3 is an optimal combination to calculate LS-BMD or TBS.

INTRODUCTION

Lumbar spine (LS) BMD and TBS are both assessed in the LS DXA scans in the same region of interest, L1-L4. We aimed to investigate the ability to predict osteoporotic fractures of all the possible adjacent LS vertebrae combinations used to calculate BMD and TBS and to evaluate if any of these combinations performs better at osteoporotic fracture prediction than the traditional L1-L4 combination.

METHODS

This study was embedded in OsteoLaus-women cohort in Switzerland. LS-DXA scans were performed using Discovery A System (Hologic). The incident vertebral fractures (VFs) and major osteoporotic fractures (MOFs) were assessed from VF assessments using Genant's method or questionnaires (non-VF MOF). We ran logistic models using TBS and BMD to predict MOF, VF, and non-VF MOF, combining different adjustment factors (age, fracture level, or BMD).

RESULTS

One thousand six hundred thirty-two women (mean ± SD) 64.4 ± 7.5 years, BMI 25.9 ± 4.5 kg/m², were followed for 4.4 years and 133 experienced MOF. The association of one SD decrease L1-L3 BMD with the odds ratios (ORs) of MOF was OR 1.32 (95%CI 1.15-1.53), L2-L4 BMD was 1.25 (95%CI 1.09-1.42), and L1-L4 BMD was 1.30 (95%CI 1.14-1.48). One SD decrease in L1-L3 TBS was more strongly associated with the odds of having a MOF (OR 1.64, 95% CI 1.34-2.00), than one SD decrease in L2-L4 TBS (OR 1.48, 95% CI 1.21-1.81), or in L1-L4 TBS (OR 1.60, CI 95% 1.32-1.95).

CONCLUSION

Current findings indicate that L1-L3 is an optimal combination for the TBS or LS-BMD calculation.

Evaluation of the bone mineral density in the Mexican female population using the Radiofrequency Echographic Multi Spectrometry (REMS) technology

The bone health status of a Mexican female population, including a cohort of 455 women aged over 40 years, was assessed by Radiofrequency Echographic Multi Spectrometry (REMS).

PURPOSE

Assessment of the bone health status in an average female Mexican population with REMS. The secondary objective investigated age- and body mass index (BMI)-related effects on the diagnostic classification and the influence of risk factors for osteoporosis.

METHODS

Women aged over 40 years underwent a REMS scan at the lumbar spine and both femoral necks. The degree of correlation of the bone mineral density (BMD) across axial sites was assessed by the Pearson correlation coefficient (r), along with the diagnostic discordance. The association between risk factors, age, and BMI and diagnostic classification was determined by the chi-squared test.

RESULTS

Four hundred seventy-one women were enrolled. Osteoporosis was diagnosed in 11.0%, 8.1%, and 8.3% of cases at the lumbar spine and right and left femoral neck, respectively. The diagnostic agreement between the lumbar spine and femoral necks was about 73% (85% considering a 0.3 T-score tolerance), whereas the agreement between the femoral necks was 97.4% (99.6% considering a 0.3 T-score tolerance). Most of discordant cases were minor discordances. The correlation between the lumbar spine and femoral neck was r = 0.82 and 0.85, respectively, whereas both femoral necks correlated with r = 0.97. As expected, the prevalence of osteoporosis increased with age and decreased as BMI increased.

CONCLUSION

The widespread applicability of the non-ionizing REMS technology has been demonstrated in a representative Mexican cohort, covering wide age and BMI ranges. Age and BMI variations correlate with the prevalence of osteoporosis, in line with the recent scientific literature.

Sarcopenia: how to measure, when and why

Sarcopenia indicates a loss of skeletal muscle mass, a condition that leads to a decline in physical performance. In 2018, the European Working Group on Sarcopenia in Older People met to update the original definition of sarcopenia: New scientific and clinical insights were introduced to emphasize the importance of muscle strength loss as a prime indicator of probable sarcopenia. In addition, the skeletal muscle is not only the organ related to mobility, but it is recognized as a secondary secretory organ too, with endocrine functions influencing several systems and preserving health. In this perspective, radiology could have a major role in early detection of sarcopenia and guarantee improvement in its treatment in clinical practice. We present here an update of clinical knowledge about sarcopenia and advantages and limitations of radiological evaluation of sarcopenia focusing on major body composition imaging modalities such as dual-energy X-ray absorptiometry, CT, and MRI. In addition, we discuss controversial such as the lack of consensus or standardization, different measurement methods, and diagnostic radiological cutoff points. Sarcopenia evaluation with radiological methods could enhance the role of radiologist in performing studies with relevant impact on medical and social outcome, placing radiology at the pinnacle of quality in evidence-based practice with high-level studies.

Sarcopenia: imaging assessment and clinical application

Sarcopenia is a progressive, generalized skeletal muscle disorder characterized by reduction of muscle mass and strength. It is associated with increased adverse outcomes including falls, fractures, physical disability, and mortality, particularly, in elderly patients. Nowadays, sarcopenia has become a specific imaging biomarker able to predict clinical outcomes of patients. Muscle fibre reduction has shown to be an unfavourable pre-operative predictive factor in patients with cancer, and is associated with worse clinical outcomes in terms of postoperative complications, morbidity, mortality, and lower tolerance of chemoradiation therapy. Several imaging modalities, including dual-energy X-ray absorptiometry, CT, MRI, and US can be used to estimate muscle mass and quality to reach the diagnosis of sarcopenia. This article reviews the clinical implications of sarcopenia, how this condition can be assessed through different imaging modalities, and future perspectives of imaging of sarcopenia.

BatchBMD as an Efficient and Accurate Dual-Energy X-ray Absorptiometry Report Generator

Dual-energy X-ray absorptiometry is the gold standard for evaluating Bone Mineral Density (BMD); however, a typical BMD report is generated in a time-inefficient manner and is prone to error. We developed a rule-based automated reporting system, BatchBMD, that accelerates DXA reporting while improving its accuracy over current systems. BatchBMD generates a structured report, customized to the specific clinical purpose. To compare BatchBMD to a Web-based Reporting (WBR) system for efficiency and accuracy, 500 examinations were randomly chosen from those performed at the Taipei Municipal Wanfang Hospital from January to March 2021. The final assessment included all 2326 examinations conducted from September 2020 to March 2021. The average reporting times were 6.7 and 10.8 min for BatchBMD and the WBR system, respectively, while accuracy was 99.4% and 98.2%, respectively. Most of the errors made by BatchBMD were digit errors in the appendicular skeletal muscle index. After correcting this, 100% accuracy across all 2326 examinations was validated. This automated and accurate BMD reporting system significantly reduces report production workload for radiologists and technicians while increasing productivity and quality. Additionally, the portable software, which employs a simple framework, can reduce deployment costs in clinical practice.

Postmenopausal osteoporosis: current status of bone densitometry

Osteoporosis is the most common of all metabolic bone disorders characterized by loss of bone strength, due to modifications in bone turnover. It leads to bone fragility and increased fracture risk. Because of the increasing aging of the world population, the number of people affected by osteoporosis is continuously increasing. The WHO operational definition of osteoporosis, based on a measurement of bone mineral density (BMD) by dual-energy X-ray absorptiometry (DXA), identifies patients at greatest risk of fracture. However, in the population overall a greater total number of fractures occurs in individuals with BMD values above threshold for osteoporosis diagnosis; for this reason, algorithms have been developed to improve the identification of individuals at high fracture risk, including clinical risk factors for fracture. The correct diagnosis of osteoporosis with an appropriate and accurate use of diagnostic imaging results in better management in terms of adequate treatment and follow-up. Moreover, screening strategies will improve identification of patients who are most likely to benefit from drug treatment to prevent fracture. All women after the age of 65 years previously untested and women after the age of 50 years with previous low trauma fractures should be screened by DXA. In fact, osteoporosis-related fractures cause a significant increase in morbidity and mortality, decreasing the quality of life, with an increasing social and economic burdens. For this reason, fracture risk assessment should be a high priority amongst health measures.

Could Radiofrequency Echographic Multi-Spectrometry (REMS) Overcome the Limitations of BMD by DXA Related to Artifacts? A Series of 3 Cases

Dual-energy X-ray absorptiometry (DXA) is considered the gold standard in the evaluation of bone mineral density (BMD) and in the diagnosis of osteoporosis.The diagnostic sensitivity of BMD at lumbar spine is frequently reduced by the presence of artifacts. This study aimed to show the usefulness of radiofrequency echographic multi-spectrometry (REMS) in determining lumbar BMD in the presence of artifacts with DXA measurements. We present 3 cases in which REMS technology, by the analysis of native raw unfiltered ultrasound signals, appears to be able to recognize and overcome the most common artifacts that affect the value of the BMD by DXA, thus allowing a better assessment of fracture risk.

Sarcopenia Diagnosis: Reliability of the Ultrasound Assessment of the Tibialis Anterior Muscle as an Alternative Evaluation Tool

Sarcopenia is a skeletal muscle disorder characterized by reduced muscle mass, strength, and performance. Muscle ultrasound can be helpful in assessing muscle mass, quality, and architecture, and thus possibly useful for diagnosing or screening sarcopenia. The objective of this study was to evaluate the reliability of ultrasound assessment of tibialis anterior muscle in sarcopenia diagnosis. We included subjects undergoing total or partial hip replacement, comparing measures with a healthy control group. We measured the following parameters: tibialis anterior muscle thickness, echogenicity, architecture, stiffness, skeletal muscle index (SMI), hand grip strength, and sarcopenia related quality of life evaluated through the SarQoL questionnaire. We included 33 participants with a mean age of 54.97 ± 23.91 years. In the study group we found reduced tibialis anterior muscle thickness compared to the healthy control group (19.49 ± 4.92 vs. 28.94 ± 3.63 mm, p < 0.05) with significant correlation with SarQoL values (r = 0.80, p < 0.05), dynamometer hand strength (r = 0.72, p < 0.05) and SMI (r = 0.76, p < 0.05). Moreover, we found reduced stiffness (32.21 ± 12.31 vs. 27.07 ± 8.04 Kpa, p < 0.05). AUC measures of ROC curves were 0.89 predicting reduced muscle strength, and 0.97 predicting reduced SMI for tibialis anterior muscle thickness, while they were 0.73 and 0.85, respectively, for muscle stiffness. Our findings showed that ultrasound assessment of tibialis anterior muscle might be considered a reliable measurement tool to evaluate sarcopenia.

Treatment of osteoporosis with teriparatide: The Slovenian experience

The aim of this study was to investigate the characteristics of postmenopausal women prescribed with teriparatide in Slovenia, during the first decade after its approval, and the predictors of bone mineral density (BMD) improvement with treatment. We retrospectively studied postmenopausal osteoporotic patients prescribed with teriparatide at tertiary center from 2006 to 2015. BMD was measured at standard sites by DXA at baseline, after 12 and 24 months. 25-hydroxyvitamin D and procollagen type I N-terminal propeptide (PINP) were measured at the same time-points. The inclusion criteria were met by 188 women (aged 71 years on average), 151 (80.3%) with postmenopausal and 37 (19.7%) with glucocorticoid-induced osteoporosis. Everyone had at least one fracture, 159 (84.6%) had ≥2 fractures, with vertebral fractures in 172 patients (91.5%). All patients had been previously on antiresorptives for 8.6 years on average. The average BMD change at lumbar spine, total hip, and femoral neck was +5.0%, −1.1%, and +0.3% after 24 months of treatment, respectively. Higher baseline PINP was associated with higher BMD increase at all sites after the first 12 months. Teriparatide was prescribed mostly to elderly women with severe osteoporosis who had sustained two or more fractures despite long-term antiresorptive therapy. Baseline PINP might predict initial BMD increase with teriparatide.

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.

Fracture Risk Assessment: An Update

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Our ability to accurately identify high fracture risk in individuals has improved as the volume of clinical data has expanded and fracture risk assessment tools have been developed.

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Given its accessibility, affordability, and low radiation exposure, dual x-ray absorptiometry (DXA) remains the standard for osteoporosis screening and monitoring response to treatment.

➤

The trabecular bone score (TBS) is a DXA software add-on that uses lumbar spine DXA imaging to produce an output that correlates with bone microarchitecture. It has been identified as an independent fracture risk factor and may prove useful in further stratifying fracture risk among those with a bone mineral density (BMD) in the osteopenic range (-1.0 to -2.4 standard deviations), in those with low-energy fractures but normal or only mildly low BMD, or in those with conditions known to impair bone microarchitecture.

➤

Fracture risk assessment tools, including the Fracture Risk Assessment Tool (FRAX), Garvan fracture risk calculator, and QFracture, evaluate the impact of multiple clinical factors on fracture risk, even in the absence of BMD data. Each produces an absolute fracture risk output over a defined interval of time. When used appropriately, these enhance our ability to identify high-risk patients and allow us to differentiate fracture risk among patients who present with similar BMDs.

➤

For challenging clinical cases, a combined approach is likely to improve accuracy in the identification of high-risk patients who would benefit from the available osteoporosis therapies.

Magnetic resonance imaging-based partial volume-corrected 18F-sodium fluoride positron emission tomography in the femoral neck

OBJECTIVES

18F-sodium fluoride (NaF) is a radiotracer used in PET that reflects calcium metabolism and osteoblastic activity. In this study, we assessed the construct validity of a novel application of global assessment to measure NaF uptake in the femoral neck as a method of evaluating physiologic changes in osteoblastic metabolism with age.

METHODS

Whole-body NaF-PET/computed tomography (CT) images and MRI of 24 male patients with a history of nonmetastatic prostate cancer between the ages of 36 and 82 years (67.8 ± 9.6) were analyzed. A region of interest delineated the entire femoral neck on the PET/CT image to determine the mean standardized uptake value (SUVmean). Correction for the partial volume effect was performed by measuring the volume of inert yellow bone marrow by MRI segmentation. Multiple linear regression was used to assess the relationship of uptake with age and body weight.

RESULTS

The SUVmean with and without partial volume correction decreased with respect to age (P = 0.001 and P = 0.002, respectively). Body weight was not significantly related to any measured PET parameter.

CONCLUSION

Our results support the use of global NaF uptake with magnetic resonance-derived partial volume correction in the femoral neck. Because osteoblastic metabolism is known to decrease with normal aging, the observed decrease in NaF uptake constitutes evidence for convergent validity, indicating that the proposed methodology likely reflects systemic osteoblastic activity. Future studies of this methodology are warranted in other instances of varying osteoblastic activity such as in metabolic bone diseases and for the evaluation of therapy targeting osteoblastic metabolism.

Does Quantitative Ultrasound at the Calcaneus Predict an Osteoporosis Diagnosis in Postmenopausal Women from the Silesia Osteo Active Study?

The aims of the study were to assess the clinical conformity between quantitative ultrasound (QUS) and densitometry with use of the standard World Health Organization T-score thresholds to determine optimal diagnostic cutoff values for QUS T-scores in different age groups. Three hundred sixty-five postmenopausal Caucasian women were enrolled into the study and divided into two age groups (<65 y and ≥65 y). Skeletal status was assessed using QUS measurements at the calcaneus and bone densitometry at the spine and proximal femur (Hologic Explorer, Bedford, MA, USA). QUS measurement results expressed as the stiffness index (SI) correlated significantly with both femoral neck bone mineral density (r = 0.51, p < 0.0001) and lumbar spine bone mineral density (r = 0.52, p < 0.0001). On the basis of receiver operating characteristic curve analyses, the thresholds for correspondence between QUS T-score values and T-score -2.5SD in dual X-ray absorptiometry (DXA) were established. They ranged between -1.63SD and -1.70SD in relation to femoral neck DXA and between -1.22SD and -1.51SD in relation to lumbar spine DXA, depending on age category. In conclusion, the study described here confirmed that QUS measurements at the calcaneus may provide information comparable to DXA examinations at the femoral neck and lumbar spine in postmenopausal women.

Bone densitometry worldwide: a global survey by the ISCD and IOF

In a global survey of fracture liaison services, most reported that DXA access met needs. However, adherence to basic DXA quality and reporting procedures was confirmed by only around 50% of institutions and many required education for operators/interpreters. Overall, there is significant variability in the access to, and quality of, DXA services worldwide.

INTRODUCTION

While the use of dual-energy X-ray absorptiometry (DXA) has been widely adopted worldwide for the assessment of bone mineral density, the quality of DXA facilities is unknown. To address this, a global survey of fracture liaison services (FLS) was conducted by the International Society for Clinical Densitometry (ISCD) and the International Osteoporosis Foundation (IOF) to assess the quality of their DXA facilities.

METHODS

A questionnaire for the accessibility and quality of DXA services was co-created by representatives of the ISCD and the IOF and made available to institutions who participated in the Capture the Fracture Best Practice Framework. From a list of 331 contacted invitees, 124 FLS centres responded; analyses were based on 121 centres with suitable data.

RESULTS

Over 70% of institutions reported that, for over 90% of the time, DXA access met service needs, and the scanning/reporting quality was perceived as excellent. However, 25% of DXA facilities reported not being accredited by a professional/governmental organization, and adherence to some basic DXA quality assurance and reporting procedures was confirmed by < 50% of services. Importantly, in excess of 50% of institutions stated that they desired ongoing education in osteoporosis and DXA for operators and interpreters.

CONCLUSION

There is significant variability in the access to and quality of DXA services for established FLS worldwide. Despite two decades of training initiatives in osteoporosis densitometry, many centres are falling short of the standards of the IOF-ISCD Osteoporosis Essentials criteria.

Multidisciplinary team training reduces the error rate of DXA image

Establishing the hospital's own standard operating procedures (SOPs) and team training including physicians and technologists reduces the error rate of dual-energy X-ray absorptiometry (DXA) measurement. In addition, when monitoring DXA images, it is necessary to check whether region of interest (ROI) and bone mapping are properly set as well as patient positioning.

INTRODUCTION

Physicians often experience poor quality DXA images, which affects osteoporosis treatment. The purpose of this study is to analyze the change in the error rate of DXA images after a multidisciplinary team training including physicians and technologists.

METHODS

Experienced physicians and DXA technologists formed a training team to establish SOPs for DXA measurement. The training team instructed the other related hospital personnel for a month. We set the criteria of measurement errors (9 items for the lumbar spine image and 8 items for the proximal femur image). With these criteria, a total of 637 images (320 images before training and 317 images after training) were analyzed to check the frequency and distribution of errors before and after training.

RESULTS

The most common error when measuring the lumbar spine image before training was inadequate bone mapping (51.9%), and when measuring the proximal femur image was the incorrect area of the ROI of the femoral neck (37.2%). The most improved error after training was inadequate bone mapping (33.3% improvement) in the lumbar spine image and inadequate internal rotation (13.6% improvement) in the proximal femur image. Errors were significantly reduced by 23.2% in the lumbar spine, 9.0% in the proximal femur, and 9.2% in both the regions.

CONCLUSIONS

Establishing SOPs and multidisciplinary team training effectively reduced the error rate of DXA images.

Bone Mineral Densitometry Reporting: Pearls and Pitfalls

Dual-energy X-ray absorptiometry (DXA) is the method of choice for assessing bone mineral density (BMD). Unfortunately, the performance and interpretation of DXA can be challenging and errors are common. In fact, it has been reported that up to 90% of BMD reports contain at least 1 error. Errors can be the result of technique or interpretative in nature or both and can result in inappropriate diagnosis and management. In this article, we review the various types of pitfalls frequently encountered by physicians interpreting DXA studies. Being aware of these pitfalls will help readers recognize and avoid them when encountered in clinical practice.

Bone microarchitectural analysis using ultra-high-resolution CT in tiger vertebra and human tibia

Background

To reveal trends in bone microarchitectural parameters with increasing spatial resolution on ultra-high-resolution computed tomography (UHRCT) in vivo and to compare its performance with that of conventional-resolution CT (CRCT) and micro-CT ex vivo.

Methods

We retrospectively assessed 5 tiger vertebrae ex vivo and 16 human tibiae in vivo. Seven-pattern and four-pattern resolution imaging were performed on tiger vertebra using CRCT, UHRCT, and micro-CT, and on human tibiae using UHRCT. We measured six microarchitectural parameters: volumetric bone mineral density (vBMD), trabecular bone volume fraction (bone volume/total volume, BV/TV), trabecular thickness (Tb.Th), trabecular number (Tb.N), trabecular separation (Tb.Sp), and connectivity density (ConnD). Comparisons between different imaging resolutions were performed using Tukey or Dunnett T3 test.

Results

The vBMD, BV/TV, Tb.N, and ConnD parameters showed an increasing trend, while Tb.Sp showed a decreasing trend both ex vivo and in vivo. Ex vivo, UHRCT at the two highest resolutions (1024- and 2048-matrix imaging with 0.25-mm slice thickness) and CRCT showed significant differences (p ≤ 0.047) in vBMD (51.4 mg/cm³ and 63.5 mg/cm³versus 20.8 mg/cm³), BV/TV (26.5% and 29.5% versus 13.8 %), Tb.N (1.3 l/mm and 1.48 l/mm versus 0.47 l/mm), and ConnD (0.52 l/mm³ and 0.74 l/mm³versus 0.02 l/mm³, respectively). In vivo, the 512- and 1024-matrix imaging with 0.25-mm slice thickness showed significant differences in Tb.N (0.38 l/mm versus 0.67 l/mm, respectively) and ConnD (0.06 l/mm³versus 0.22 l/mm³, respectively).

Conclusions

We observed characteristic trends in microarchitectural parameters and demonstrated the potential utility of applying UHRCT for microarchitectural analysis.

Common errors in dual-energy X-ray absorptiometry scans in imaging centers in Ecuador

Dual-energy X-ray absorptiometry is recognized for measuring bone mineral density. The lack of knowledge can lead to errors both in the acquisition of information and in its analysis and subsequent interpretation. The main errors in Ecuadorian Centers were positioning of the patient to the equipment and incorrect analyzed area.

PURPOSE/INTRODUCTION

Dual-energy X-ray absorptiometry (DXA) is recognized as the gold standard for measuring bone mineral density (BMD) with acceptable errors, good precision, and reproducibility. However, the training of operators in different centers and countries is not standardized, and the lack of knowledge can lead to errors both in the acquisition of information and in its analysis and subsequent interpretation. The purpose was to determine the most common errors in the performance of bone densitometry from different imaging centers in Ecuador.

METHODS

Cross-sectional descriptive study. We collected DXA scans from different imaging centers in Ecuador. Data from the DXA scan included city of origin, type of specialist that requested it, and densitometry diagnosis. The DXA images provided were analyzed double blind by experts in the field from Argentina.

RESULTS

From a total of 141 patients with a mean age of 61 ± 10 years, 93.6% were women. About 78% of the DXA scans came from private imaging centers and 22% from public centers, 95% of all came from the city of Guayaquil. The machines used were Hologic 50.4% and Lunar 49.6%. The densitometric diagnosis was 16.3% normal, 46.1% osteoporosis, and 37.6% osteopenia. A total of 112 left hip and 49 right hip scans were analyzed from which 31.2% and 22.4% had errors in patient positioning, respectively, mainly internal or external rotation. About 140 lumbar scans were analyzed from which 21.4% had patient positioning errors (not centered or not straight). Also in 38.5% the vertebral area did not correspond to L1-L4. About 3.5% had artifacts such as a metal bar or implant. The region of interest was misplaced in 24.1% of the lumbar scans and 19.9% of the femur.

CONCLUSIONS

DXA quality standards exist but are often not implemented in clinical practice. When studies are performed incorrectly, it can lead to important errors in diagnosis and therapy. Physicians interested in the management of osteoporosis, although not directly involved in the performance and interpretation of DXA, should be familiar with the protocols to minimize errors and allow the proper use of bone densitometry.

Imaging of sarcopenia: old evidence and new insights

To date, sarcopenia is considered a patient-specific imaging biomarker able to predict clinical outcomes. Several imaging modalities, including dual-energy X-ray absorptiometry (DXA), computed tomography (CT), magnetic resonance (MR), and ultrasound (US), can be used to assess muscle mass and quality and to achieve the diagnosis of sarcopenia. With different extent, all these modalities can provide quantitative data, being thus reproducible and comparable over time. DXA is the one most commonly used in clinical practice, with the advantages of being accurate and widely available, and also being the only radiological tool with accepted cutoff values to diagnose sarcopenia. CT and MR are considered the reference standards, allowing the evaluation of muscle quality and fatty infiltration, but their application is so far mostly limited to research. US has been always regarded as a minor tool in sarcopenia and has never gained enough space. To date, CT is probably the easiest and most promising modality, although limited by the long time needed for muscle segmentation. Also, the absence of validated thresholds for CT measurements of myosteatosis requires that future studies should focus on this point. Radiologists have the great potential of becoming pivotal in the context of sarcopenia. We highly master imaging modalities and know perfectly how to apply them to different organs and clinical scenarios. Similarly, radiologists should master the culture of sarcopenia, and its clinical aspects and relevant implications for patient care. The medical and scientific radiological community should promote specific educational course to spread awareness among professionals. KEY POINTS: • DXA is an accurate, reproducible, and widely available imaging modality to evaluate body composition, being the most commonly used radiological tool to diagnose sarcopenia in clinical practice • CT and MR are the gold standard imaging modalities to assess muscle mass and quality, but no clear cutoff values have been reported to identify sarcopenia, limiting the application of these modalities to research purposes • US has shown to be accurate in the evaluation of muscle trophism, especially in the thigh, but its current application in sarcopenia is limited.

Cross-calibration, Least Significant Change and Quality Assurance in Multiple Dual-Energy X-ray Absorptiometry Scanner Environments: 2019 ISCD Official Position

In preparation for the International Society for Clinical Densitometry Position Development Conference (PDC) 2019 in Kuala Lumpur, Malaysia, a cross-calibration and precision task force was assembled and tasked to review the literature, summarize the findings, and generate positions to answer 4 related questions provided by the PDC Steering Committee, which expand upon the current ISCD official positions on these subjects. (1) How should a provider with multiple dual-energy X-ray absorptiometry (DXA) scanners of the same make and model calculate least significant change (LSC)? (2) How should a provider with multiple DXA systems with the same manufacturer but different models calculate LSC? (3) How should a provider with multiple DXA systems from different manufacturers and models calculate LSC? (4) Are there specific phantom procedures that one can use to provide trustworthy in vitro cross calibration for same models, different models, and different makes? Based on task force deliberations and the resulting systematic literature reviews, 3 new positions were developed to address these more complex scenarios not addressed by current official positions on single scanner cross calibration and LSC. These new positions provide appropriate guidance to large multiple DXA scanner providers wishing to offer patients flexibility and convenience, and clearly define good clinical practice requirements to that end.

Radiofrequency echographic multi-spectrometry for the in-vivo assessment of bone strength: state of the art-outcomes of an expert consensus meeting organized by the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO)

PURPOSE

The purpose of this paper was to review the available approaches for bone strength assessment, osteoporosis diagnosis and fracture risk prediction, and to provide insights into radiofrequency echographic multi spectrometry (REMS), a non-ionizing axial skeleton technique.

METHODS

A working group convened by the European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis met to review the current image-based methods for bone strength assessment and fracture risk estimation, and to discuss the clinical perspectives of REMS.

RESULTS

Areal bone mineral density (BMD) measured by dual-energy X-ray absorptiometry (DXA) is the consolidated indicator for osteoporosis diagnosis and fracture risk assessment. A more reliable fracture risk estimation would actually require an improved assessment of bone strength, integrating also bone quality information. Several different approaches have been proposed, including additional DXA-based parameters, quantitative computed tomography, and quantitative ultrasound. Although each of them showed a somewhat improved clinical performance, none satisfied all the requirements for a widespread routine employment, which was typically hindered by unclear clinical usefulness, radiation doses, limited accessibility, or inapplicability to spine and hip, therefore leaving several clinical needs still unmet. REMS is a clinically available technology for osteoporosis diagnosis and fracture risk assessment through the estimation of BMD on the axial skeleton reference sites. Its automatic processing of unfiltered ultrasound signals provides accurate BMD values in view of fracture risk assessment.

CONCLUSIONS

New approaches for improved bone strength and fracture risk estimations are needed for a better management of osteoporotic patients. In this context, REMS represents a valuable approach for osteoporosis diagnosis and fracture risk prediction.

Does a spinal implant alter dual energy X-ray absorptiometry body composition measurements?

Background

Most manufacturer manuals do not verify the use of dual energy X-ray absorptiometry for body composition analysis in subjects with a metal implant. This study aimed to quantify the effects of a spinal implant on body composition, and to determine whether unadjusted lean mass estimates are valid for patients with a spinal implant.

Methods

A total of 30 healthy subjects were recruited. Three consecutive scans were performed for each participant, one with and two without extraneous spinal implant, without repositioning between scans. Lean, fat and bone estimates in the total body, trunk and limb were measured.

Results

Precision errors for all total and regional body compositions were within the recommended ranges. Bone masses in the trunk and total body were significantly increased with spinal implant, and the increases exceeded the least significant change. For total and regional lean and fat estimates, the measurements between subjects with and without metal implants were in substantial to almost perfect agreement and the differences were not significant and did not exceed the least significant change.

Conclusions

Spinal metal artifacts significantly increased the total body and trunk bone mass but the differences in lean- and fat-related estimates at total and regional body levels and all estimates in the extremity remained within the clinical acceptable range. Thus, a spinal implant may not compromise screening of patients for fat and lean masses using dual energy X-ray absorptiometry. Application of image reconstruction or a filtering algorithm may help reduce the effect of metallic artifacts and further study is needed.

Radiofrequency echographic multispectrometry compared with dual X-ray absorptiometry for osteoporosis diagnosis on lumbar spine and femoral neck

An innovative, non-ionizing technique to diagnose osteoporosis on lumbar spine and femoral neck was evaluated through a multicenter study involving 1914 women. The proposed method showed significant agreement with reference gold standard method and, therefore, a potential for early osteoporosis diagnoses and possibly improved patient management.

INTRODUCTION

To assess precision (i.e., short term intra-operator precision) and diagnostic accuracy of an innovative non-ionizing technique, REMS (Radiofrequency Echographic Multi Spectrometry), in comparison with the clinical gold standard reference DXA (dual X-ray absorptiometry), through an observational multicenter clinical study.

METHODS

In a multicenter cross-sectional observational study, a total of 1914 postmenopausal women (51-70 years) underwent spinal (n = 1553) and/or femoral (n = 1637) DXA, according to their medical prescription, and echographic scan of the same anatomical sites performed with the REMS approach. All the medical reports (DXA and REMS) were carefully checked to identify possible errors that could have caused inaccurate measurements: erroneous REMS reports were excluded, whereas erroneous DXA reports were re-analyzed where possible and otherwise excluded before assessing REMS accuracy. REMS precision was independently assessed.

RESULTS

In the spinal group, quality assessment on medical reports produced the exclusion of 280 patients because of REMS errors and 78 patients because of DXA errors, whereas 296 DXA reports were re-analyzed and corrected. Analogously, in the femoral group there were 205 exclusions for REMS errors, 59 exclusions for DXA errors, and 217 re-analyzed DXA reports. In the resulting dataset (n = 1195 for spine, n = 1373 for femur) REMS outcome showed a good agreement with DXA: the average difference in bone mineral density (BMD, bias ± 2SD) was -0.004 ± 0.088 g/cm² for spine and - 0.006 ± 0.076 g/cm² for femur. Linear regression showed also that the two methods were well correlated: standard error of the estimate (SEE) was 5.3% for spine and 5.8% for femur. REMS precision, expressed as RMS-CV, was 0.38% for spine and 0.32% for femur.

CONCLUSIONS

The REMS approach can be used for non-ionizing osteoporosis diagnosis directly on lumbar spine and femoral neck with a good level of accuracy and precision. However, a more rigorous operator training is needed to limit the erroneous acquisitions and to ensure the full clinical practicability.

DXA Errors Are Common and Reduced by Use of a Reporting Template

OBJECTIVE

High quality dual energy X-ray absorptiometry (DXA) acquisition, analysis, and reporting demands technical and interpretive excellence. We hypothesized that DXA errors are common and of such magnitude that incorrect clinical decisions might result. In this 2-phase study, we evaluated DXA technical and interpretation error rates in a clinical population and subsequently assessed if implementing an interpretation template reduced errors.

METHODS

In phase 1, DXA scans of 345 osteoporosis clinic referrals were reviewed by International Society for Clinical Densitometry-certified technologists (n = 3) and physicians (n = 3). Technologists applied International Society for Clinical Densitometry performance standards to assess technical quality. Physicians assessed reporting compliance with published guidance, relevance of technical errors and determined overall and major error prevalence. Major errors were defined as "provision of inaccurate information that could potentially lead to incorrect patient care decisions." In phase 2, a DXA reporting template was implemented at 2 clinical DXA sites after which the 3 physicians reviewed 200 images and reports as above. The error prevalence was compared with the 298 patients in phase 1 from these sites.

RESULTS

In phase 1, technical errors were identified in 90% of patients and affected interpretation in 13%. Interpretation errors were present in 80% of patients; 42% were major. The most common major errors were reporting incorrect information on bone mineral density change (70%) and incorrect diagnosis (22%). In phase 2, at these 2 clinical sites, major errors were present in 37% before and 17% after template implementation. Template usage reduced the odds of major error by 66% (odds ratio 0.34, 95% confidence interval 0.21, 0.53, and p < 0.0001).

CONCLUSION

DXA technical and interpretation errors are extremely common and likely adversely affect patient care. Implementing a DXA reporting template reduces major errors and should become common practice. Additional interventions, such as requiring initial and ongoing training and/or certification for technologists and interpreters, are suggested.

Diagnosis and Monitoring of Osteoporosis With 18F-Sodium Fluoride PET: An Unavoidable Path for the Foreseeable Future

The prevalence of metabolic bone diseases particularly osteoporosis and its precursor, osteopenia, continue to grow as serious global health issues today. On a worldwide perspective, 200million people suffer from osteoporosis and in 2005, over 2million fracture incidents were estimated due to osteoporosis in the United States. Currently, osteoporosis and other metabolic bone diseases are evaluated primarily through dual energy X-ray absorptiometry, and rarely by bone biopsy with tetracycline labeling or Technetium-99m (^99mTc) based bone scintigraphy. Deficiencies in these methods have prompted the use of more precise methods of assessment. This review highlights the use of ¹⁸F-sodium fluoride (NaF) with PET (NaF-PET), NaF-PET/CT, or NaF-PET/MRI in the evaluation of osteoporosis and osteopenia in the lumbar spine and hip. This imaging modality provides a molecular perspective with respect to the underlying metabolic alterations that lead to osseous disorders by measuring bone turnover through standardized uptake values. Its sensitivity and ability to examine the entire skeletal system make it a more superior imaging modality compared to standard structural imaging techniques. Further research is needed to determine its accuracy in reflecting the efficacy of therapeutic interventions in metabolic bone diseases.

CONSENSUS STATEMENT BY THE AMERICAN ASSOCIATION OF CLINICAL ENDOCRINOLOGISTS AND AMERICAN COLLEGE OF ENDOCRINOLOGY ON THE QUALITY OF DXA SCANS AND REPORTS

OBJECTIVE

High-quality dual-energy X-ray absorptiometry (DXA) scans are necessary for accurate diagnosis of osteoporosis and monitoring of therapy; however, DXA scan reports may contain errors that cause confusion about diagnosis and treatment. This American Association of Clinical Endocrinologists/American College of Endocrinology consensus statement was generated to draw attention to many common technical problems affecting DXA report conclusions and provide guidance on how to address them to ensure that patients receive appropriate osteoporosis care.

METHODS

The DXA Writing Committee developed a consensus based on discussion and evaluation of available literature related to osteoporosis and osteodensitometry.

RESULTS

Technical errors may include errors in scan acquisition and/or analysis, leading to incorrect diagnosis and reporting of change over time. Although the International Society for Clinical Densitometry advocates training for technologists and medical interpreters to help eliminate these problems, many lack skill in this technology. Suspicion that reports are wrong arises when clinical history is not compatible with scan interpretation (e.g., dramatic increase/decrease in a short period of time; declines in previously stable bone density after years of treatment), when different scanners are used, or when inconsistent anatomic sites are used for monitoring the response to therapy. Understanding the concept of least significant change will minimize erroneous conclusions about changes in bone density.

CONCLUSION

Clinicians must develop the skills to differentiate technical problems, which confound reports, from real biological changes. We recommend that clinicians review actual scan images and data, instead of relying solely on the impression of the report, to pinpoint errors and accurately interpret DXA scan images.

ABBREVIATIONS

AACE = American Association of Clinical Endocrinologists; BMC = bone mineral content; BMD = bone mineral density; DXA = dual-energy X-ray absorptiometry; ISCD = International Society for Clinical Densitometry; LSC = least significant change; TBS = trabecular bone score; WHO = World Health Organization.

Diagnostic imaging of osteoporosis and sarcopenia: a narrative review

Osteoporosis and sarcopenia represent two major health problems with an increasing prevalence in the elderly population. The correlation between these diseases has been widely reported, leading to the development of the term "osteosarcopenia" to diagnose those patients suffering from both diseases. Several imaging methods for the diagnosis and management of osteoporosis exist, with dual-energy X-ray absorptiometry (DXA) being the most commonly used for measuring bone mineral density (BMD). Imaging technique other than DXA is represented by conventional radiography, computed tomography (CT) and ultrasound (US). Similarly, the imaging technologies used to detect loss of skeletal muscle mass in sarcopenia include DXA, CT, US and magnetic resonance imaging (MRI). These methods differ in terms of reliability, radiation exposure and costs. CT and MRI represent the gold standard for evaluating body composition (BC), but are costly and time-consuming. DXA remains the most often used technology for studying BC, being quick, widely available and with low radiation exposure.

Imaging of metabolic bone disease

Osteoporosis is the most important metabolic bone disease, with a wide distribution among the elderly. It is characterized by low bone mass and micro architectural deterioration of bone tissue, leading to enhanced bone fragility and a consequent increase in fracture risk. Identify bone weakening with an appropriate and accurate use of diagnostic imaging is of critical importance in the diagnosis and follow-up of osteoporotic patients. The aim of this review is to evaluate the detection rates of the different imaging modalities in the evaluation of bone strength, in the assessment of fracture risk and in the management of fragility fractures. (www.actabiomedica.it)

Quality in dual-energy X-ray absorptiometry scans

Dual-energy X-ray absorptiometry (DXA) is the gold standard for measuring bone mineral density (BMD), making the diagnosis of osteoporosis, and for monitoring changes in BMD over time. DXA data are also used in the determination of fracture risk. Procedural steps in DXA scanning can be broken down into scan acquisition, analysis, interpretation, and reporting. Careful attention to quality control pertaining to these procedural steps should theoretically be beneficial in patient management. Inattention to procedural steps and errors that may occur at each step has the possibility of providing information that would inform inappropriate clinical decisions, generating unnecessary healthcare expenses and ultimately causing avoidable harm to patients. This article reviews errors in DXA scanning that affect trueness and precision related to the machine, the patient, and the technologist and reviews articles which document problems with DXA quality in clinical and research settings. An understanding of DXA errors is critical for DXA quality; programs such as certification of DXA technologists and interpreters help in assuring quality bone densitometry. As DXA errors are common, pay for performance requiring DXA technologists and interpreters to be certified and follow quality indicators is indicated.

DXA: 30years and counting: Introduction to the 30th anniversary issue

Dual-energy X-ray absorptiometry (DXA) has a colorful history of development and evolution over the past 30years, from early predecessors that were cumbersome and limited in their clinical applications to current elegant instruments with a wide range of uses. DXA is used to diagnose osteoporosis, assess fracture risk, and monitor changes in bone mineral density (BMD). Non-BMD applications include vertebral fracture assessment, measurement of hip geometry, measurement of whole body tissue mass (i.e., bone, fat, and lean mass), abdominal aortic calcification detection and trabecular bone score measurement. This is an introduction to a special issue of this journal devoted to the celebration of the innovators in this field, the progress that has been made, and the challenges that remain.

Evaluation of bone mineral density of the lumbar spine using a novel phantomless dual-energy CT post-processing algorithm in comparison with dual-energy X-ray absorptiometry

Background

Current techniques for evaluation of bone mineral density (BMD) commonly require phantom calibration. The purpose of this study was to evaluate a novel algorithm for phantomless in vivo dual-energy computed tomography (DECT)-based assessment of BMD of the lumbar spine in comparison with dual-energy X-ray absorptiometry (DEXA).

Methods

Data from clinically indicated DECT and DEXA examinations within two months comprising the lumbar spine of 47 patients were retrospectively evaluated. By using a novel automated dedicated post-processing algorithm for DECT, the trabecular bone of lumbar vertebrae L1–L4 was selected and analysed. Linear correlation was analysed using Pearson’s product-moment correlation coefficient for the comparison of the results from DECT and DEXA.

Results

A total of 186 lumbar vertebrae in 47 patients (mean age, 58 years; age range, 24–85 years) were analysed, 24 men (mean age, 55 years; age range, 24–85 years) and 23 women (mean age, 59 years; age range, 31–80 years). Mean BMD of L1–L4 determined with DEXA was 0.985 g/cm² and 20/47 patients (42.6%) showed an osteoporotic BMD (T score lower than – 2.5) of at least two vertebrae. Average DECT-based BMD of L1–L4 was 86.8 mg/cm³. Regression analysis demonstrated a lack of correlation between DECT- and DEXA-based BMD values with a Pearson’s product-moment correlation coefficient r = 0.4205.

Conclusions

Dedicated post-processing of DECT data using a novel algorithm for retrospective phantomless BMD assessment of the trabecular bone of lumbar vertebrae from clinically indicated DECT examinations is feasible.

Trends in radiology and experimental research

European Radiology Experimental, the new journal launched by the European Society of Radiology, is placed in the context of three general and seven radiology-specific trends. After describing the impact of population aging, personalized/precision medicine, and information technology development, the article considers the following trends: the tension between subspecialties and the unity of the discipline; attention to patient safety; the challenge of reproducibility for quantitative imaging; standardized and structured reporting; search for higher levels of evidence in radiology (from diagnostic performance to patient outcome); the increasing relevance of interventional radiology; and continuous technological evolution. The new journal will publish not only studies on phantoms, cells, or animal models but also those describing development steps of imaging biomarkers or those exploring secondary end-points of large clinical trials. Moreover, consideration will be given to studies regarding: computer modelling and computer aided detection and diagnosis; contrast materials, tracers, and theranostics; advanced image analysis; optical, molecular, hybrid and fusion imaging; radiomics and radiogenomics; three-dimensional printing, information technology, image reconstruction and post-processing, big data analysis, teleradiology, clinical decision support systems; radiobiology; radioprotection; and physics in radiology. The journal aims to establish a forum for basic science, computer and information technology, radiology, and other medical subspecialties.

Common Mistakes in the Dual-Energy X-ray Absorptiometry (DXA) in Turkey. A Retrospective Descriptive Multicenter Study

BACKGROUND

Osteoporosis is a widespread metabolic bone disease representing a global public health problem currently affecting more than two hundred million people worldwide. The World Health Organization states that dual-energy X-ray absorptiometry (DXA) is the best densitometric technique for assessing bone mineral density (BMD). DXA provides an accurate diagnosis of osteoporosis, a good estimation of fracture risk, and is a useful tool for monitoring patients undergoing treatment. Common mistakes in BMD testing can be divided into four principal categories: 1) indication errors, 2) lack of quality control and calibration, 3) analysis and interpretation errors, and 4) inappropriate acquisition techniques. The aim of this retrospective multicenter descriptive study is to identify the common errors in the application of the DXA technique in Turkey.

METHODS

All DXA scans performed during the observation period were included in the study if the measurements of both, the lumbar spine and proximal femur were recorded. Forearm measurement, total body measurements, and measurements performed on children were excluded. Each examination was surveyed by 30 consultants from 20 different centers each informed and trained in the principles of and the standards for DXA scanning before the study.

RESULTS

A total of 3,212 DXA scan results from 20 different centers in 15 different Turkish cities were collected. The percentage of the discovered erroneous measurements varied from 10.5% to 65.5% in the lumbar spine and from 21.3% to 74.2% in the proximal femur. The overall error rate was found to be 31.8% (n = 1021) for the lumbar spine and 49.0% (n = 1576) for the proximal femur.

CONCLUSION

In Turkey, DXA measurements of BMD have been in use for over 20 years, and examination processes continue to improve. There is no educational standard for operator training, and a lack of knowledge can lead to significant errors in the acquisition, analysis, and interpretation.