Dual-energy X-ray Absorptiometry Bone Mineral Density Research Articles

Chemotherapy effects on bone mineral density and microstructure in women with breast cancer.

Chemotherapy involves the administration of steroids to prevent nausea and vomiting; however, its effect on bone microstructure remains unknown. This study aimed to evaluate the changes in bone mineral density (BMD) and bone microstructure associated with chemotherapy using high-resolution peripheral quantitative computed tomography (HR-pQCT) in women with early breast cancer. This prospective single-arm observational study included non-osteoporotic, postmenopausal women with breast cancer. The patients underwent dual-energy X-ray absorptiometry (DXA), HR-pQCT, and tartrate-resistant acid phosphatase-5b (TRACP-5b) or procollagen type-I N-terminal propeptide (P1NP) measurements at baseline, end of chemotherapy, and 6months after chemotherapy. The primary endpoint was the change in total volumetric BMD at the distal tibia and radius. Eighteen women were included in the study (median age: 57years; range: 55-62years). At 6months after chemotherapy, HR-pQCT indicated a significant decrease in total volumetric BMD (median: distal tibia -4.5%, p < 0.01; distal radius -2.3%, p < 0.01), cortical volumetric BMD (-1.9%, p < 0.01; -0.8%, p = 0.07, respectively), and trabecular volumetric BMD (-1.1%, p = 0.09; -3.0%, p < 0.01, respectively). The DXA BMD also showed a significant decrease in the lumbar spine (median: -4.5%, p < 0.01), total hip (-5.5%, p < 0.01), and femoral neck (-4.2%, p < 0.01). TRACP-5b and P1NP levels were significantly increased at the end of chemotherapy compared to baseline. Postmenopausal women undergoing chemotherapy for early breast cancer experienced significant BMD deterioration in weight-bearing bone, which was further reduced 6months after chemotherapy.

Quantitative calcium-based assessment of osteoporosis in dual-layer spectral CT

ObjectivesTo evaluate a novel calcium-only imaging technique (VCa) with subtracted bone marrow in osteoporosis in dual-layer CT (DLCT) compared to conventional CT images (CI) and dual-energy X-ray absorptiometry (DXA). Material and methodsImages of a multi-energy CT phantom with calcium inserts, quantitative CT calibration phantom, and of 55 patients (mean age: 64.6 ± 11.5 years) were acquired on a DLCT to evaluate bone mineral density (BMD). CI, calcium-suppressed images, and VCa were calculated. For investigating the association of VCa and CI with DXA a subsample of 30 patients (<90 days between DXA and CT) was used. Multiple regression analysis was performed to identify further factors improving the prediction of DXA BMD. ResultsThe calcium concentrations of the CT phantom inserts were significantly associated with CT numbers from VCa (R2 = 0.94) and from CI (R2 = 0.89–0.92). VCa showed significantly higher CT numbers than CI in the phantom (p ≤ 0.001) and clinical setting (p < 0.001). CT numbers from VCa were significantly associated with CI (R2 = 0.95, p < 0.001) and with DXA (R2 = 0.31, p = 0.007), whereas no significant association between DXA and CI was found. Prediction of DXA BMD based on CT numbers derived from VCa yielded R2 = 0.76 in multiple regression analysis. ROC for the differentiation of normal from pathologic BMD in VCa yielded an AUC of 0.7, and a cut-off value of 126HU (sensitivity: 0.90; specificity: 0.47). ConclusionVCa images showed better agreement with DXA and known calcium concentrations than CI, and could be used to estimate BMD. A VCa cut-off of 126HU could be used to identify abnormal bone mineral density.

End-to-End Semi-Supervised Opportunistic Osteoporosis Screening Using Computed Tomography.

Osteoporosis is the most common metabolic bone disease and can cause fragility fractures. Despite this, screening utilization rates for osteoporosis remain low among populations at risk. Automated bone mineral density (BMD) estimation using computed tomography (CT) can help bridge this gap and serve as an alternative screening method to dual-energy X-ray absorptiometry (DXA). The feasibility of an opportunistic and population agnostic screening method for osteoporosis using abdominal CT scans without bone densitometry phantom-based calibration was investigated in this retrospective study. A total of 268 abdominal CT-DXA pairs and 99 abdominal CT studies without DXA scores were obtained from an oncology specialty clinic in the Republic of Korea. The center axial CT slices from the L1, L2, L3, and L4 lumbar vertebrae were annotated with the CT slice level and spine segmentation labels for each subject. Deep learning models were trained to localize the center axial slice from the CT scan of the torso, segment the vertebral bone, and estimate BMD for the top four lumbar vertebrae. Automated vertebra-level DXA measurements showed a mean absolute error (MAE) of 0.079, Pearson's r of 0.852 (P<0.001), and R2 of 0.714. Subject-level predictions on the held-out test set had a MAE of 0.066, Pearson's r of 0.907 (P<0.001), and R2 of 0.781. CT scans collected during routine examinations without bone densitometry calibration can be used to generate DXA BMD predictions.

Evaluation of Bone Health Using High Resolution Peripheral Quantitative Computed Tomography in Survivors of Paediatric Acute Lymphoblastic Leukemia

Bone mass accrual, bone architecture, and strength may be impaired in children with a history of acute lymphoblastic leukemia (ALL) resulting in low bone mineral density (BMD) and fractures. The Children's Oncology Group recommends evaluating ALL survivors' bone health with dual-energy X-ray absorptiometry (DXA) testing. However, DXA testing may not accurately measure bone health in survivors due to low bone area for height, short stature, growth delays or decreased lean muscle mass. Further, it does not differentiate between trabecular and cortical bone, nor does it provide insights into bone microarchitecture and strength. High-resolution peripheral quantitative computed tomography (HR-pQCT) is a three-dimensional non-invasive imaging modality that provides a comprehensive assessment bone microarchitecture, volumetric BMD (vBMD) of both cortical and trabecular bone, and bone strength. In adult patients, HR-pQCT parameters have been shown to predict incident fractures. In this pilot study we utilized HR-pQCT to evaluate bone microarchitecture, vBMD, bone geometry and bone strength of peri-pubertal and pubertal survivors of ALL compared to healthy controls. Methods: We prospectively recruited ALL survivors (&amp;gt;1 year off therapy) with a DXA BMD Z-score between -2.0 to 0 within the proceeding six months, who were in early-late puberty (pre-pubertal patients excluded), and aged 11 to 18 years, along with healthy controls in the same age range at a single academic pediatric center in Canada. While a BMD Z-score of -2.0 to 0 has historically been considered normal, many children with Z-scores in this range have skeletal fragility and an increased fracture risk. Patients were excluded if they had comorbidity that impacts bone microarchitecture (ex. chronic kidney disease), were on a medication that impacts bone health (ex. corticosteroids) or had a genetic syndrome that increased their sensitivity to radiation (ex. Ataxia Telangiectasia). HR-pQCT of the distal radius and tibia was performed using the a standardized protocol. Bone mass was compared using total, trabecular and cortical vBMD, bone architecture was compared using cortical porosity and bone strength was compared using failure load. HR-pQCT derived variables were compared between ALL and control groups following stratification by sex. HR-pQCT values were summarized using medians and interquartile ranges and medians were compared using the Wilcoxon signed-rank test. Demographic and clinical characteristics were compared using the chi-square test. All tests were two tailed and p&amp;lt;0.05 was considered significant. Results: A total of 59 subjects were recruited (34 ALL survivors, 25 healthy controls). The sex of participants was male for 56.0% (n=14) of controls and 61.7% (n=21) of ALL survivors and female for 44.0% (n=11) of controls and 38.3% (n=13) of survivors. All survivors had received corticosteroids and methotrexate, and five (15%) had received cranial radiation. ALL survivors were not more likely than controls to report a history of a fracture (32.4%, n=11 vs. 16%, n=4). Additional data regarding the participants demographics is presented in Table 1. Male survivors had a lower radial trabecular vBMD, tibial total vBMD, and tibial trabecular vBMD, and a higher tibial failure load compared to healthy male controls. Female survivors had a lower radial total vBMD, radial trabecular vBMD, tibial total vBMD, and tibial trabecular vBMD. Female ALL survivors also had higher radial and tibial failure loads compared to healthy female controls. No differences in cortical porosity or cortical vBMD were identified between survivors and healthy controls. Complete HR-pQCT data is presented in Table 2. Conclusions: We demonstrated differences in the HR-pQCT parameters of peripubertal and pubertal ALL survivors compared to healthy controls. Survivors had reductions in key HR-pQCT parameters and an increased tibial failure load compared to healthy controls. In future studies HR-pQCT should be performed at a uniform time point post ALL therapy and used to predict future adverse bone health outcome such as fractures. Using this HR-pQCT guided approach ALL survivors at greatest risk of an adverse bone health outcome can be offered early interventions to prevent these outcomes.

THU603 Bone Fragility In Mild Autonomous Cortisol Secretion: A Cross-Sectional Cohort Study

Abstract Disclosure: C.D. Zhang: None. S. Singh: None. J. Saini: None. M. Suresh: None. K. Thangamuthu: None. R. Nathani: None. A.L. Ebbehøj: None. V. Fell: None. S.J. Achenbach: None. E.J. Atkinson: None. S. Khosla: None. I. Bancos: None. Background: Patients with mild autonomous cortisol secretion (MACS) have higher rates of fractures compared to patients with non-functioning adrenal nodules, but bone mass is typically only modestly reduced. We hypothesized that chronic exposure to mild levels of cortisol excess may lead to a deterioration in bone quality. Objective: To characterize the effect of MACS on bone metabolism and bone microarchitecture, as measured by high-resolution peripheral quantitative computed tomography (HR-pQCT). Methods: In this cross-sectional single-center study, patients with MACS were matched by age, sex, and gonadal status to referent subjects without adrenal nodules. MACS was defined as serum cortisol concentration &amp;gt;1.8 mcg/dL after the 1 mg overnight dexamethasone suppression test (1-mg DST), in the absence of a classic Cushingoid phenotype. Those with other known secondary causes of osteoporosis and/or on pharmacologic treatment for low bone mass were excluded. All study participants underwent a bone health interview, blood draw for bone turnover markers, dual-energy x-ray absorptiometry (DXA) scan with trabecular bone score (TBS), and HR-pQCT of the non-dominant radius and tibia. Participants with a recent fracture within 12 months were excluded from the analysis of bone turnover markers. The Kruskal-Wallis test was used to compare measurements between groups. Results: A total of 82 patients with MACS and 82 referent subjects were prospectively enrolled between 1/2019 and 7/2022. The median age of study participants at the time of enrolment was 57 years (interquartile range [IQR], 47-65), and 57 (70%) were women. In the MACS cohort, the median cortisol following 1-mg DST was 3.2 mcg/dL (IQR, 2.3-6.5) with median ACTH of 8.7 pg/mL (IQR, 6.0-14.0) and median DHEA-S of 42.0 mcg/dL (IQR 23.0-68.0). While no differences in bone mineral density (BMD) were observed at any site (lumbar spine, total hip, femoral neck, or distal radius) between the two groups, patients with MACS had decreased TBS (1.374 vs 1.467, P &amp;lt;0.001) and lower osteocalcin concentrations (16.9 vs. 19.7 ng/mL, P = 0.005) than referent subjects without adrenal nodules. On HR-pQCT at the tibia, patients with MACS had significantly reduced trabecular volumetric BMD (151.6 vs 167.4 mg hydroxyapatite/cm3, P = 0.002), trabecular bone volume/tissue volume ratio (0.219 vs 0.237, P = 0.011), and number of trabeculae (1.428 vs 1.506 1/mm, P = 0.045), while trabecular separation (0.707 vs 0.656, P = 0.023) was increased compared to referent subjects. Conclusions: Patients with MACS have altered bone metabolism and microstructural deterioration that is not evident on routine DXA BMD testing. These changes may mediate their increased fracture risk and could serve as biomarkers of cortisol-induced changes in the bone. Presentation: Thursday, June 15, 2023

Evaluating alternatives to dual-energy x-ray absorptiometry for assessing bone quality in patients undergoing spine surgery.

The purpose of this study was to compare and contrast lumbar bone quality and osteoporosis/osteopenia screening results via dual-energy x-ray absorptiometry (DEXA), CT, and MRI. A consecutive series of 426 candidates screened for lumbar disc replacement over a 5-year period beginning in 2018 was reviewed. Patients with a preoperative lumbar spine DEXA scan and a CT and/or MRI scan were included. The primary outcome measures included the bone mineral density (BMD) and osteoporosis or osteopenia classification from DEXA scans, Hounsfield units (HUs) for CT, and vertebral bone quality (VBQ) assessment for MRI. Patients were included if they had a DEXA scan within 1 year of an MRI or CT scan. DEXA BMD scores from composite or level-by-level reports were recorded. Asynchronous MRI and CT measurements were conducted using PACS. Interrater and intrarater reliability scores were generated for both CT and MRI measurements and ranged from 1.000 for MRI L1-4 scans to 0.683 for MRI VBQ. All 3 types of scans were statistically significantly correlated with one another; however, CT was more strongly correlated with the lumbar DEXA value (r = 0.439, p < 0.001). The correlation between MRI VBQ and DEXA was -0.103, (p < 0.045). The CT level-by-level measurements correlate with the corresponding level-by-level DEXA BMD values (correlation ranging from 0.531 to 0.289, p < 0.001 to p = 0.007). CT HU values were more strongly related to osteoporosis/osteopenia classification based on DEXA T-scores than were MRI VBQ values. Receiver operating characteristic analyses found that the area under the curve was 0.817 for CT and 0.539 for MRI. These results demonstrate that CT HUs more closely correlate to DEXA scores than MRI VBQ in this population of patients undergoing surgery for symptomatic disc degeneration. Thus, CT may be an alternative to DEXA for assessing VBQ in this population.

Exploring the Paradox of Bone Mineral Density in Type 2 Diabetes: A Comparative Study Using Opportunistic Chest CT Texture Analysis and DXA.

This study aimed to validate the application of CT texture analysis in estimating Bone Mineral Density (BMD) in patients with Type 2 Diabetes (T2D) and comparing it with the results of dual-energy X-ray absorptiometry (DXA) in a normative cohort. We analyzed a total of 510 cases (145 T2D patients and 365 normal patients) from a single institution. DXA-derived BMD and CT texture analysis-estimated BMD were compared for each participant. Additionally, we investigated the correlation among 45 different texture features within each group. The correlation between CT texture analysis-estimated BMD and DXA-derived BMD in T2D patients was consistently high (0.94 or above), whether measured at L1 BMD, L1 BMC, total hip BMD, or total hip BMC. In contrast, the normative cohort showed a modest correlation, ranging from 0.66 to 0.75. Among the 45 texture features, significant differences were found in the Contrast V 64 and Contrast V 128 features in the normal group. In essence, our study emphasizes that the clinical assessment of bone health, particularly in T2D patients, should not merely rely on traditional measures, such as DXA BMD. Rather, it may be beneficial to incorporate other diagnostic tools, such as CT texture analysis, to better comprehend the complex interplay between various factors impacting bone health.

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

SummaryThis 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.IntroductionCalcaneal 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.MethodsBone 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.ResultsReliability 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.ConclusionsThe 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.

Detecting whether L1 or other lumbar levels would be excluded from DXA bone mineral density analysis during opportunistic CT screening for osteoporosis using machine learning.

One or more vertebrae are sometimes excluded from dual-energy X-ray absorptiometry (DXA) analysis if the bone mineral density (BMD) T-score estimates are not consistent with the other lumbar vertebrae BMD T-score estimates. The goal of this study was to build a machine learning framework to identify which vertebrae would be excluded from DXA analysis based on the computed tomography (CT) attenuation of the vertebrae. Retrospective review of 995 patients (69.0% female) aged 50years or greater with CT scans of the abdomen/pelvis and DXA within 1year of each other. Volumetric semi-automated segmentation of each vertebral body was performed using 3D-Slicer to obtain the CT attenuation of each vertebra. Radiomic features based on the CT attenuation of the lumbar vertebrae were created. The data were randomly split into training/validation (90%) and test datasets (10%). We used two multivariate machine learning models: a support vector machine (SVM) and a neural net (NN) to predict which vertebra(e) were excluded from DXA analysis. L1, L2, L3, and L4 were excluded from DXA in 8.7% (87/995), 9.9% (99/995), 32.3% (321/995), and 42.6% (424/995) patients, respectively. The SVM had a higher area under the curve (AUC = 0.803) than the NN (AUC = 0.589) for predicting whether L1 would be excluded from DXA analysis (P = 0.015) in the test dataset. The SVM was better than the NN for predicting whether L2 (AUC = 0.757 compared to AUC = 0.478), L3 (AUC = 0.699 compared to AUC = 0.555), or L4 (AUC = 0.751 compared to AUC = 0.639) were excluded from DXA analysis. Machine learning algorithms could be used to identify which lumbar vertebrae would be excluded from DXA analysis and should not be used for opportunistic CT screening analysis. The SVM was better than the NN for identifying which lumbar vertebra should not be used for opportunistic CT screening analysis.

Discrepancy between DXA and CT-based assessment of spine bone mineral density.

Adequate bone mineral density (BMD) is necessary for success in spine surgery. Dual-energy X-ray absorptiometry (DXA) is the gold standard in determining BMD but may give spuriously high values. Hounsfield units (HU) from computed tomography (CT) may provide a more accurate depiction of the focal BMD encountered during spine surgery. Our objective is to determine the discrepancy rate between DXA and CT BMD determinations and how often DXA overestimates BMD compared to CT. We retrospectively reviewed 93 patients with both DXA and CT within 6months. DXA lumbar spine and overall T scores were classified as osteoporotic (T Score ≤ - 2.5) or non-osteoporotic (T Score > -2.5). L1 vertebral body HU were classified as osteoporotic or non-osteoporotic using cutoff thresholds of either ≤ 135 HU or ≤ 110 HU. Corresponding DXA and HU classifications were compared to determine disagreement and overestimation rates. Using lumbar T scores, the CT vs DXA disagreement rate was 40-54% depending on the HU threshold. DXA overestimated BMD 97-100% of the time compared to CT. Using overall DXA T scores, the disagreement rate was 33-47% with DXA greater than CT 74-87% of the time. In the sub-cohort of 10 patients with very low HU (HU < 80), DXA overestimated BMD compared to CT in every instance. There is alarge discrepancy between DXA and CT BMD determinations. DXA frequently overestimates regional BMD encountered during spine surgery compared with CT. While DXA remains the gold standard in determining BMD, CT may play an important role in defining the focal BMD pertinent to spine surgery.

MRI Quantification of Cortical Bone Porosity, Mineralization, and Morphologic Structure in Postmenopausal Osteoporosis.

Background Preclinical studies have suggested that solid-state MRI markers of cortical bone porosity, morphologic structure, mineralization, and osteoid density are useful measures of bone health. Purpose To explore whether MRI markers of cortical bone porosity, morphologic structure, mineralization, and osteoid density are affected in postmenopausal osteoporosis (OP) and to examine associations between MRI markers and bone mineral density (BMD) in postmenopausal women. Materials and Methods In this single-center study, postmenopausal women were prospectively recruited from January 2019 to October 2020 into two groups: participants with OP who had not undergone treatment, defined as having any dual-energy x-ray absorptiometry (DXA) T-score of -2.5 or less, and age-matched control participants without OP (hereafter, non-OP). Participants underwent MRI in the midtibia, along with DXA in the hip and spine, and peripheral quantitative CT in the midtibia. Specifically, MRI measures of cortical bone porosity (pore water and total water), osteoid density (bound water [BW]), morphologic structure (cortical bone thickness), and mineralization (phosphorous [P] density [31P] and 31P-to-BW concentration ratio) were quantified at 3.0 T. MRI measures were compared between OP and non-OP groups and correlations with BMD were assessed. Results Fifteen participants with OP (mean age, 63 years ± 5 [SD]) and 19 participants without OP (mean age, 65 years ± 6) were evaluated. The OP group had elevated pore water (11.6 mol/L vs 9.5 mol/L; P = .007) and total water densities (21.2 mol/L vs 19.7 mol/L; P = .03), and had lower cortical bone thickness (4.8 mm vs 5.6 mm; P < .001) and 31P density (6.4 mol/L vs 7.5 mol/L; P = .01) than the non-OP group, respectively, although there was no evidence of a difference in BW or 31P-to-BW concentration ratio. Pore and total water densities were inversely associated with DXA and peripheral quantitative CT BMD (P < .001), whereas cortical bone thickness and 31P density were positively associated with DXA and peripheral quantitative CT BMD (P = .01). BW, 31P density, and 31P-to-BW concentration ratio were positively associated with DXA (P < .05), but not with peripheral quantitative CT. Conclusion Solid-state MRI of cortical bone was able to help detect potential impairments in parameters reflecting porosity, morphologic structure, and mineralization in postmenopausal osteoporosis. © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Bae in this issue.

Prediction of osteoporosis from proximal femoral cortical bone thickness and Hounsfield unit value with clinical significance.

Utilizing dual-energy x-ray absorptiometry (DXA) to assess bone mineral density (BMD) was not routine in many clinical scenarios, leading to missed diagnoses of osteoporosis. The objective of this study is to obtain effective parameters from hip computer tomography (CT) to screen patients with osteoporosis and predict their clinical outcomes. A total of 375 patients with hip CT scans for intertrochanteric fracture were included. Among them, 56 patients possessed the data of both hip CT scans and DXA and were settled as a training group. The cortical bone thickness (CTh) and Hounsfield unit (HU) values were abstracted from 31 regions of interest (ROIs) of the proximal femur. In the training group, the correlations between these parameters and BMD were investigated, and their diagnostic efficiency of osteoporosis was assessed. Finally, 375 patients were divided into osteoporotic and nonosteoporotic groups based on the optimal cut-off values, and the clinical difference between subgroups was evaluated. The CTh value of ROI 21 and the HU value of ROI 14 were moderately correlated with the hip BMD [r = 0.475 and 0.445 (p < 0.001), respectively]. The best diagnostic effect could be obtained by defining osteoporosis as CTh value < 3.19 mm in ROI 21 or HU value < 424.97 HU in ROI 14, with accuracies of 0.821 and 0.883, sensitivities of 84% and 76%, and specificities of 71% and 87%, respectively. The clinical outcome of the nonosteoporotic group was better than that of the osteoporotic group regardless of the division criteria. The CTh and HU values of specific cortex sites in the proximal femur were positively correlated with BMD of DXA at the hip. Thresholds for osteoporosis based on CTh and HU values could be utilized to screen osteoporosis and predict clinical outcomes.

Dual-Energy CT-Based Bone Mineral Density Has Practical Value for Osteoporosis Screening around the Knee.

Introduction: Adequate bone quality is essential for long term biologic fixation of cementless total knee arthroplasty (TKA). Recently, vertebral bone quality evaluation using dual-energy computed tomography (DECT) has been introduced. However, the DECT bone mineral density (BMD) in peripheral skeleton has not been correlated with Hounsfield units (HU) or central dual-energy X-ray absorptiometry (DXA), and the accuracy remains unclear. Materials and methods: Medical records of 117 patients who underwent TKA were reviewed. DXA was completed within three months before surgery. DECT was performed with third-generation dual source CT in dual-energy mode. Correlations between DXA, DECT BMD and HU for central and periarticular regions were analyzed. Receiver operating characteristic (ROC) curves were plotted and area under the curve (AUC), optimal threshold, and sensitivity and specificity of each region of interest (ROI) were calculated. Results: Central DXA BMD was correlated with DECT BMD and HU in ROIs both centrally and around the knee (all p < 0.01). The diagnostic accuracy of DECT BMD was higher than that of DECT HU and was also higher when the T-score for second lumbar vertebra (L2), rather than for the femur neck, was used as the reference standard (all AUC values: L2 > femur neck; DECT BMD > DECT HU, respectively). Using the DXA T-score at L2 as the reference standard, the optimal DECT BMD cut-off values for osteoporosis were 89.2 mg/cm3 in the distal femur and 78.3 mg/cm3 in the proximal tibia. Conclusion: Opportunistic volumetric BMD assessment using DECT is accurate and relatively simple, and does not require extra equipment. DECT BMD and HU are useful for osteoporosis screening before cementless TKA.

P885: PROSPECTIVE ASSESSMENT OF MYELOMA TUMOUR BURDEN AND BONE DISEASE USING DW-MRI AND EXPLORATORY BONE BIOMARKERS

Background: Key clinical priorities for multiple myeloma (MM) are to reduce tumour burden and complications, of which lytic bone disease is the major cause of morbidity. To guide treatment, there is a pressing need for biomarkers that can accurately quantify MM tumour burden and associated bone disease. To this end, Diffusion-Weighted Magnetic Resonance Imaging (DW-MRI) and bone turnover markers are promising radiological and serum metrics, respectively, although their clinical value in prospective assessment is unclear. Aims: LOOMIS was a single-centre observational cohort study that evaluated the relative merits of DW-MRI and bone turnover markers in prospectively assessing tumour burden and bone disease when added to standard clinical assessment, in patients with MM and monoclonal gammopathy of undetermined significance (MGUS). Methods: A total of 67 patients were enrolled (14 newly diagnosed MM, 12 relapsed MM, 15 smouldering MM, 14 MGUS and 12 healthy volunteers) between March 2018 and March 2020. At baseline (and 6-month follow-up for MM/MGUS), participants had a DW-MRI scan and serum measurements of established (P1NP, CTX-1, ALP) and exploratory (DKK1, sclerostin, RANKL:OPG ratio) bone turnover markers. MM/MGUS patients additionally had standard myeloma bloods and Dual-Energy X-ray Absorptiometry (DXA) at each visit, as correlates of tumour burden and bone loss. DW-MRI scans were double reported by expert Radiologists for Apparent Diffusion Coefficient (ADC) measurements of lytic bone lesion(s), and Myeloma Response Assessment and Diagnosis System (MY-RADS) Response Assessment Category (RAC) scoring. Patients were classified by International Myeloma Working Group (IMWG) response criteria as a clinical correlate of therapy response. Results: On assessment of baseline tumour burden, there was no correlation between single lesion DW-MRI ADC and serum paraprotein [p>0.05]; however, there was moderate positive correlation between serum DKK1 and serum paraprotein [r=0.39, p=0.04]. At follow-up, radiological MY-RADS RAC scoring correlated with conventional IMWG response criteria [p=0.015]; additionally, longitudinal relative change in serum DKK1 differed between IMWG-defined therapy responders (37% decrease) and non-responders (15% increase) [p<0.01]. On baseline assessment of bone loss, there was moderate positive correlation between serum sclerostin and DXA bone mineral density at femoral neck [r=0.40, p<0.01] and lumbar spine [r=0.54, p<0.001]. At follow-up, there was a moderate negative correlation between longitudinal % change in the RANKL:OPG ratio and % change in DXA bone mineral density at femoral neck [r= -0.45, p<0.01]. Summary/Conclusion: Our prospective trial validates DW-MRI-based MY-RADS RAC scoring as a qualitative radiological tool to assess therapy response. Whilst previous work has supported single lytic lesion ADC measurements as a correlate of tumour volume, we did not find this; small sample size and prior chemotherapy in our study may have limited our ability to detect this. In comparison, serum bone turnover markers such as DKK1 may provide a more global measure to quantify myeloma burden both at baseline diagnosis and longitudinally with therapy. Additionally, our data highlight serum sclerostin and RANKL:OPG ratio as potential biomarkers to assess and monitor bone loss. Overall, our study highlights emerging radiological and serum biomarkers of tumour burden and associated bone loss in MM and MGUS, which merit further exploration alongside uniformly treated cohorts, to better understand their clinical utility.

Bone mineral density in women newly diagnosed with breast cancer: a prospective cohort study

Estrogen may have opposing effects on health, namely increasing the risk of breast cancer and improving bone health by increasing bone mineral density (BMD). The objective of this study was to compare dual-energy X-ray absorptiometry (DXA) BMD between women newly diagnosed with breast cancer and matched controls without breast cancer. Women newly diagnosed with breast cancer treated between April 2012 and October 2017 were prospectively enrolled. A control group was established of women with negative mammography or breast ultrasound, matched 1:1 by age, body mass index, parity, and the use of hormone replacement therapy. All those included had DXA BMD, and lab assessments at enrollment. Of 869 women with newly diagnosed breast cancer, 464 signed informed consent. Of the 344 who completed the study protocol, 284 were matched to controls. Overall, the mean age was 58 years. Compared to the control group, for the breast cancer group, the mean vitamin D level was lower (48.9 ± 19.0 vs. 53.8 ± 28.8 nmol/L, p = 0.022); and mean values were higher of total hip BMD (0.95 ± 0.14 vs. 0.92 ± 0.12 g/cm2, p = 0.002), T score (−0.38 ± 1.17 vs. −0.68 ± 0.98, p = 0.002), and Z score (0.32 ± 1.09 vs. 0.01 ± 0.88, p < 0.001). Among the women with breast cancer, no correlations were found of baseline BMD with tumor size or grade, nodal involvement, or breast cancer stage. We concluded that women with newly diagnosed breast cancer tend to have higher BMD than women with similar characteristics but without breast cancer. This implies that BMD might be considered a biomarker for breast cancer risk.

Evaluation of nutritional status and related factors in children with cystic fibrosis.

This study aimed to evaluate the nutritional status and body composition in children with cystic fibrosis (CF), in accordance with the new nutritional targets defined by European Society for Clinical Nutrition and Metabolism (ESPEN), the European Society for Paediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) and the European Cystic Fibrosis Society (ECFS) 2016. In this cross-sectional study, data were collected prospectively in a single centre. A record was made for a total of 95 patients with CF of clinical data. Anthropometric data were evaluated using the World Health Organization growth standards. The bone mineral density (BMD) z-score was adjusted for height by measuring dual-energy X-ray absorptiometry (DXA). The speed of sound z-score values were measured with quantitative ultrasound (QUS). The nutritional status was normal in 37.9% of patients aged < 2 years and 33.3% of patients aged 2-18 years. When the DXA BMD z-score values were corrected for height, it was determined that the BMD deficit was less. The calcaneus QUS SOS z-score mean value was lower than the mean height for age z-score adjusted BMD (BMDHAZ). The malnutrition rates of CF patients were higher than the rates previously reported in literature. As there are insufficient nutritional data in Turkey, there is a need for multi-centre studies to determine the frequency of malnutrition according to the new classifications. It is clear that QUS measurements cannot replace DXA in the diagnosis of osteopenic bone disease. However, when low values are determined with QUS as the first recommended measurement in the screening of bone status, it can be considered appropriate to confirm the status with DXA.

Trabecular Bone Score Could Not Predict the Bone Mineral Density of Proximal Humerus.

BackgroundOsteoporosis is an important clinical factor for tendon healing after arthroscopic rotator cuff repair (ARCR). Conventional dual energy X-ray absorptiometry (DXA) of the hip and lumbar spine (LS) does not represent proximal humeral bone mineral density (BMD). Theoretically, direct measurement of the BMD of the proximal humerus is the best method; however, it is not popular and is non-standardized. Therefore, we evaluate whether the trabecular bone score (TBS) using LS DXA would represent proximal humeral BMD.MethodsConventional hip and LS DXA and proximal humeral BMD were measured in 212 consecutive ARCR patients, and TBS was calculated using LS DXA. Comparative analysis between the affected and contralateral asymptomatic shoulders was done; moreover, correlation analysis was conducted to evaluate the representativity of TBS for proximal humeral BMD. Regression analysis was performed to elucidate the risk factor of intraoperative suture anchor failure (ISAF).ResultsBMDs of the affected shoulder were significantly lower than those of the contralateral side (all P<0.05). TBS failed to present a strong correlation with proximal humeral BMD (correlation coefficients 0.155–0.506, all P<0.05), and the BMD of the greater tuberosity (GT) of the proximal humerus was revealed to be a sole risk factor for ISAF (odds ratio, 0.01, P=0.020).ConclusionsTBS and conventional hip and LS DXA did not represent proximal humeral BMD. Furthermore, among the various radiological measurements, the BMD of the GT was a sole risk factor of ISAF. Therefore, further research for the direct measurement of proximal humeral BMD is mandatory to predict proximal humeral focal osteoporosis.

Bone-sparing effects of rituximab and body composition analysis in a cohort of postmenopausal women affected by rheumatoid arthritis - retrospective study.

ObjectiveOsteoporosis is the most common bone tissue disease and it is characterized by a reduced bone mineral density (BMD). The main physiopathological mechanisms converge on the uncoupling between bone formation and resorption, thus leading to an enhanced risk of fractures. Several papers have documented the inverse relationships linking high inflammatory cytokines, anti-citrullinated protein antibodies, rheumatoid factor, and BMD in rheumatoid arthritis (RA). Rituximab (RTX) is a chimeric monoclonal antibody directed against the CD20 receptor of B cells. Since the Food and Drug Administration approved it for RA in 2006, there have been many clinical experiences regarding its use. Nevertheless, few studies evaluate the effect of rituximab on BMD. RA is a disease characterized by immune dysfunction with high levels of inflammatory cytokines, autoantibodies, and it is reasonable that a B cell depleting therapy could restore a physiological cytokine balance, thus exerting an osteoprotective effect on the bone tissue. The purpose of this paper is to highlight any difference in BMD and to assess differences in body composition over a retrospective 18-month follow-up period after RTX treatment with a B cell depleting therapy.Material and methodsWe analyzed by dual energy X-ray absorptiometry BMD expressed as g/cm2 and body composition modifications over 18 months with RTX treatment of 20 postmenopausal RA patients.ResultsAfter eighteen months of therapy with RTX, a statistically significant increase in vertebral (L1–L4) BMD and the stability of femoral BMD were documented.ConclusionsRituximab is associated with an improvement of vertebral and preservation of femoral BMD, suggesting a bone-sparing effect due to B cell depletion. Furthermore, patients displayed a redistribution of fat masses toward the hip region.

Prevalence of Female and Male Athlete Triad Risk Factors in Ultramarathon Runners.

To identify the prevalence of male and female athlete triad risk factors in ultramarathon runners and explore associations between sex hormones and bone mineral density (BMD). Multiyear cross-sectional study. One hundred-mile ultramarathon. Competing runners were recruited in 2018 and 2019. Participants completed a survey assessing eating behaviors, menstrual history, and injury history; dual-energy x-ray absorptiometry for BMD; and laboratory evaluation of sex hormones, vitamin D, and ferritin (2019 cohort only). A Triad Cumulative Risk Assessment Score was calculated for each participant. One hundred twenty-three runners participated (83 males and 40 females, mean age 46.2 and 41.8 years, respectively). 44.5% of men and 62.5% of women had elevated risk for disordered eating. 37.5% of women reported a history of bone stress injury (BSI) and 16.7% had BMD Z scores <-1.0. 20.5% of men had a history of BSI and 30.1% had Z-scores <-1.0. Low body mass index (BMI) (<18.5 kg/m 2 ) was seen in 15% of women and no men. The Triad Cumulative Risk Assessment classified 61.1% of women and 29.2% of men as moderate risk and 5.6% of both men and women as high risk. Our study is the first to measure BMD in both male and female ultramarathon runners. Our male population had a higher prevalence of low BMD than the general population; females were more likely to report history of BSI. Risk of disordered eating was elevated among our participants but was not associated with either low BMD or low BMI.

Adjuvant endocrine therapy effects on bone mineral density and microstructure in women with breast cancer

Although aromatase inhibitors (AIs) are typical drugs for cancer treatment-induced bone loss, their effects on the bone microstructure remain unclear. In this study, we evaluated changes in the bone mineral density (BMD) and bone microstructure associated with AI treatment using high-resolution peripheral quantitative computed tomography (HR-pQCT) in patients with early breast cancer. This prospective, single-arm, observational study included non-osteoporotic, postmenopausal women with hormone receptor-positive breast cancer. Patients underwent dual-energy X-ray absorptiometry (DXA), HR-pQCT, and tartrate-resistant acid phosphatase-5b (TRACP-5b) or procollagen type-I N-terminal propeptide measurements at baseline and 6 and 12months after AI therapy. The primary endpoint was changes in the total volumetric BMD (Tt.vBMD), trabecular vBMD (Tb.vBMD), and cortical vBMD (Ct.vBMD) longitudinally at the distal radius and tibia. Twenty women were included (median age 57.5years; range 55-72years). At 12months, HR-pQCT indicated a significant decrease in the Tt.vBMD (median distal radius -5.3%, p < 0.01; distal tibia -3.2%, p < 0.01), Tb.vBMD (-3.2%, p < 0.01; -1.0%, p < 0.05, respectively), and Ct.vBMD (-3.2%, p < 0.01; -2.7%, p < 0.01, respectively). Estimated bone strength was also significantly decreased. The DXA BMD value in the total hip (p < 0.01) and femoral neck (p = 0.03), but not in the lumbar spine, was significantly decreased. The TRACP-5b levels was significantly negatively associated with changes in the Tt.vBMD in both the distal radius and tibia (r = -0.53, r = -0.47, respectively) CONCLUSION: Postmenopausal women who received AIs for early breast cancer experienced significant trabecular and cortical bone deterioration and a decrease in estimated bone strength within only 1year.