Structural Predictors of Lung Function Decline in Young Smokers with Normal Spirometry.

Rationale: Chronic obstructive pulmonary disease (COPD) due to tobacco smoking commonly presents when extensive lung damage has occurred. Objectives: We hypothesized that structural change would be detected early in the natural history of COPD and would relate to loss of lung function with time. Methods: We recruited 431 current smokers (median age, 39 yr; 16 pack-years smoked) and recorded symptoms using the COPD Assessment Test (CAT), spirometry, and quantitative thoracic computed tomography (QCT) scans at study entry. These scan results were compared with those from 67 never-smoking control subjects. Three hundred sixty-eight participants were followed every six months with measurement of postbronchodilator spirometry for a median of 32 months. The rate of FEV1 decline, adjusted for current smoking status, age, and sex, was related to the initial QCT appearances and symptoms, measured using the CAT. Measurements and Main Results: There were no material differences in demography or subjective CT appearances between the young smokers and control subjects, but 55.7% of the former had CAT scores greater than 10, and 24.2% reported chronic bronchitis. QCT assessments of disease probability-defined functional small airway disease, ground-glass opacification, bronchovascular prominence, and ratio of small blood vessel volume to total pulmonary vessel volume were increased compared with control subjects and were all associated with a faster FEV1 decline, as was a higher CAT score. Conclusions: Radiological abnormalities on CT are already established in young smokers with normal lung function and are associated with FEV1 loss independently of the impact of symptoms. Structural abnormalities are present early in the natural history of COPD and are markers of disease progression. Clinical trial registered with www.clinicaltrials.gov (NCT03480347).

Quantitative computed tomography analysis of body composition changes in paediatric patients with acute lymphoblastic leukaemia.

Children with acute lymphoblastic leukaemia (ALL) are at risk for obesity and cardiometabolic diseases. To gain insight into body composition changes among children with ALL, we assessed quantitative computed tomography (QCT) data for specific body compartments (subcutaneous adipose tissue [SAT], visceral adipose tissue [VAT], total adipose tissue [TAT], lean tissue [LT], LT/TAT and VAT/SAT at lumbar vertebrae L1 and L2) at diagnosis and at off-therapy for 189 children with ALL and evaluated associations between body mass index (BMI) Z-score and clinical characteristics. BMI Z-score correlated positively with SAT, VAT and TAT and negatively with LT/TAT and VAT/SAT. At off-therapy, BMI Z-score, SAT, VAT and TAT values were higher than at diagnosis, but LT, LT/TAT and VAT/SAT were lower. Patients aged ≥10 years at diagnosis had higher SAT, VAT and TAT and lower LT and LT/TAT than patients aged 2.0-9.9 years. Female patients had lower LT and LT/TAT than male patients. Black patients had less VAT than White patients. QCT analysis showed increases in adipose tissue and decreases in LT during ALL therapy when BMI Z-scores increased. Early dietary and physical therapy interventions should be considered, particularly for patients at risk for obesity.

Erosive Progression by High-Resolution Peripheral Quantitative Computed Tomography and Conventional Radiography in Rheumatoid Arthritis.

OBJECTIVES: To investigate the diagnostic accuracy of high-resolution peripheral quantitative computed tomography (HR-pQCT) to assess erosive progression during one year compared to conventional radiography (CR) in rheumatoid arthritis (RA). METHODS: This prospective study included 359 patients with RA (disease duration ≥ 5 years) between March 2018 and October 2020. HR-pQCT and CR were obtained at inclusion and after one year. Erosive assessment was performed at two metacarpophalangeal joints of the dominant hand using HR-pQCT and progression was defined as an increase in erosion number ≥ 1 or an increase in erosive volume > least significant change. CR of hands, wrists, and feet were evaluated using Sharp/van der Heijde scores and erosive progression was defined as a 1.1-point increase in erosion score according to the smallest detectable change. RESULTS: In paired analyses (n = 310), erosive progression was identified in 30 patients using CR and in 40 patients using HR-pQCT. In the 40 patients with erosive progression on HR-pQCT, progression was not identified by CR in 33 patients. Adding HR-pQCT to CR doubled the proportion of patients identified with progression from 30 (10%) to 63 (20%) patients. Using CR as the reference, the sensitivity (% (95% CI)) of HR-pQCT for identifying erosive progression was 23.3 (9.9-42.3) and the specificity was 88.2 (83.8-91.7). CONCLUSION: A substantial proportion of patients with erosive progression are overlooked using CR only to monitor erosive progression. Adding high-resolution peripheral CT to CR doubles the proportion of patients, who may benefit from individualised therapy targeting erosive progression in RA.

Trabecular bone mineral density as measured by thoracic vertebrae predicts incident hip and vertebral fractures: the multi-ethnic study of atherosclerosis.

We evaluated the relationship of bone mineral density (BMD) by computed tomography (CT), to predict fractures in a multi-ethnic population. We demonstrated that vertebral and hip fractures were more likely in those patients with low BMD. This is one of the first studies to demonstrate that CT BMD derived from thoracic vertebrae can predict future hip and vertebral fractures. PURPOSE/INTRODUCTION: Osteoporosis affects an enormous number of patients, of all races and both sexes, and its prevalence increases as the population ages. Few studies have evaluated the association between the vertebral trabecular bone mineral density(vBMD) and osteoporosis-related hip fracture in a multiethnic population, and no studies have demonstrated the predictive value of vBMD for fractures. METHOD: We sought to determine the predictive value of QCT-based trabecular vBMD of thoracic vertebrae derived from coronary artery calcium scan for hip fractures in the Multi-Ethnic Study of Atherosclerosis(MESA), a nationwide multicenter cohort included 6814 people from six medical centers across the USA and assess if low bone density by QCT can predict future fractures. Measures were done using trabecular bone measures, adjusted for individual patients, from three consecutive thoracic vertebrae (BDI Inc, Manhattan Beach CA, USA) from non-contrast cardiac CT scans. RESULTS: Six thousand eight hundred fourteen MESA baseline participants were included with a mean age of 62.2 ± 10.2 years, and 52.8% were women. The mean thoracic BMD is 162.6 ± 46.8 mg/cm3 (95% CI 161.5, 163.7), and 27.6% of participants (n = 1883) had osteoporosis (T-score 2.5 or lower). Over a median follow-up of 17.4 years, Caucasians have a higher rate of vertebral fractures (6.9%), followed by Blacks (4.4%), Hispanics (3.7%), and Chinese (3.0%). Hip fracture patients had a lower baseline vBMD as measured by QCT than the non-hip fracture group by 13.6 mg/cm3 [P < 0.001]. The same pattern was seen in the vertebral fracture population, where the mean BMD was substantially lower 18.3 mg/cm3 [P < 0.001] than in the non-vertebral fracture population. Notably, the above substantial relationship was unaffected by age, gender, race, BMI, hypertension, current smoking, medication use, or activity. Patients with low trabecular BMD of thoracic vertebrae showed a 1.57-fold greater risk of first hip fracture (HR 1.57, 95% CI 1.38-1.95) and a nearly threefold increased risk of first vertebral fracture (HR 2.93, 95% CI 1.87-4.59) compared to normal BMD patients. CONCLUSION: There is significant correlation between thoracic trabecular BMD and the incidence of future hip and vertebral fracture. This study demonstrates that thoracic vertebrae BMD, as measured on cardiac CT (QCT), can predict both hip and vertebral fractures without additional radiation, scanning, or patient burden. Osteopenia and osteoporosis are markedly underdiagnosed. Finding occult disease affords the opportunity to treat the millions of people undergoing CT scans every year for other indications.

The diagnostic value of MRI-based vertebral bone quality score for osteoporosis or osteopenia in patients undergoing lumbar surgery: a meta-analysis.

The importance of osteoporosis assessment before lumbar surgery is well recognized. The MRI-based Vertebral Bone Quality (VBQ) score is introduced to evaluate bone quality; however, its diagnostic value has not been well documented. The purpose of this meta-analysis was to summarize the diagnostic value of the VBQ score for osteoporosis or osteopenia in patients undergoing lumbar surgery. We comprehensively searched electronic databases for studies exploring the diagnostic accuracy of the VBQ score for osteoporosis/osteopenia in patients with lumbar disease following the PRISMA guidelines. The quality of the included studies was assessed. The VBQ scores were compared between the groups, and the pooled sensitivity, specificity, and summary receiver operating characteristic (ROC) were calculated. Publication bias was assessed, and meta-regression was conducted. We included 17 studies with a total of 2815 patients, with a mean age of 66.4 years and a percentage of females of 72.5%. According to the QUADAS-2 tool, the quality of the included studies was relatively high. The results showed a significantly higher VBQ score in the osteoporosis/osteopenia group compared with the control group. According to the mean VBQ cutoff value of 3.02 ± 0.38 for the diagnosis of osteoporosis, the pooled sensitivity and specificity were 0.76 and 0.74, respectively, and the AUC was 0.81. According to the mean VBQ cutoff value of 2.31 ± 0.18 for the diagnosis of osteopenia, the pooled sensitivity and specificity were 0.78 and 0.58, respectively, and the AUC was 0.76. The MRI-based VBQ score could provide useful information for identifying patients with low bone mass who need further evaluation. Future prospective studies are still needed to evaluate the complementary role of the VBQ score.

Bone health in SATB2-associated syndrome: Results from a large prospective cohort and recommendations for surveillance.

Alterations in SATB2 result in SATB2-associated syndrome (SAS; Glass syndrome, OMIM 612313), an autosomal dominant multisystemic disorder predominantly characterized by developmental delay, craniofacial anomalies, and growth retardation. The bone phenotype of SAS has been less explored until recently and includes a variety of skeletal deformities, increased risk of low bone mineral density (BMD) with a propensity to fractures, and other biochemical abnormalities that suggest elevated bone turnover. We present the results of ongoing surveillance of bone health from 32 individuals (47% females, 3-18 years) with molecularly-confirmed SAS evaluated at a multidisciplinary clinic. Five individuals (5/32, 16%) were documented to have BMD Z-scores by DXA scans of -2.0 SD or lower and 7 more (7/32, 22%) had Z-scores between -1 and - 2 SD at the lumbar spine or the total hip. Alkaline phosphatase levels were found to be elevated in 19 individuals (19/30, 63%) and determined to correspond to bone-specific alkaline phosphatase elevations when measured (11/11, 100%). C-telopeptide levels were found to be elevated when adjusted by age and gender in 6 individuals (6/14, 43%). Additionally, the two individuals who underwent bone cross-sectional geometry evaluation by peripheral quantitative computed tomography were documented to have low cortical bone density for age and sex despite concurrent DXA scans that did not have this level of decreased density. While we could not identify particular biochemical abnormalities that predicted low BMD, the frequent elevations in markers of bone formation and resorption further confirmed the increased bone turnover in SAS. Based on our results and other recently published studies, we propose surveillance guidelines for the skeletal phenotype of SAS.

Misinterpretations about CT numbers, material decomposition, and elemental quantification.

BACKGROUND: Quantitative CT imaging, particularly iodine and calcium quantification, is an important CT-based biomarker. PURPOSE: This study quantifies sources of errors in quantitative CT imaging in both single-energy and spectral CT. MATERIALS AND METHODS: This work examines the theoretical relationship between CT numbers, linear attenuation coefficient, and material quantification. We derive four understandings: (1) CT numbers are not proportional with element mass in vivo, (2) CT numbers are proportional with element mass only when contained in a voxel of pure water, (3) iodine-water material decomposition is never accurate in vivo, and (4) for error-free material decomposition a voxel must only consist of the basis decomposition vectors. Misinterpretation-based errors are calculated using the National Institute of Standards and Technology (NIST) XCOM database for: tissue chemical compositions, clinical concentrations of hydroxyapatite (HAP), and iodine. Quantification errors are also demonstrated experimentally using phantoms. RESULTS: In single-energy CT, misinterpretation-induced errors for HAP density in adipose, muscle, lung, soft tissue, and blood ranged from 0-132%, i.e., a mass error of 0-749 mg/cm3. In spectral CT, errors with iodine in the same tissues resulted in a range of < 0.1-33% error, resulting in a mass error of < 0.1-1.2 mg/mL. CONCLUSION: Our work demonstrates material quantification is fundamentally limited when measured in vivo due to measurement conditions differing from assumed and the errors are at or above detection limits for bone mineral density (BMD) and spectral iodine quantification. To define CT-derived biomarkers, the errors we demonstrate should either be avoided or built into uncertainty bounds. CLINICAL RELEVANCE STATEMENT: Improving error bounds in quantitative CT biomarkers, specifically in iodine and BMD quantification, could lead to improvements in clinical care aspects based on quantitative CT. KEY POINTS: CT numbers are only proportional with element mass only when contained in a voxel of pure water, therefore iodine-water material decomposition is never accurate in vivo. Misinterpretation-induced errors ranged from 0-132% for HAP density and < 0.1-33% in spectral CT with iodine. For error-free material decomposition, a voxel must only consist of the basis decomposition vectors.

Real-life effects of pharmacological osteoporosis treatments on bone mineral density by quantitative computed tomography.

INTRODUCTION: Monitoring of bone mineral density (BMD) is used to assess pharmacological osteoporosis therapy. This study examined the real-life effects of antiresorptive and osteoanabolic treatments on volumetric BMD (vBMD) of the spine by quantitative computed tomography (QCT). MATERIALS AND METHODS: Patients aged ≥ 50 years with a vBMD < 120 mg/ml had ≥ 2 QCT. For analysis of therapy effects, the pharmacological treatment and the duration of each therapy were considered. Identical vertebrae were evaluated in all vBMD measurements for each patient. A linear mixed model with random intercepts was used to estimate the effects of pharmacological treatments on vBMD. RESULTS: A total of 1145 vBMD measurements from 402 patients were analyzed. Considering potential confounders such as sex, age, and prior treatment, a reduction in trabecular vBMD was estimated for oral bisphosphonates (- 1.01 mg/ml per year; p < 0.001), intravenous bisphosphonates (- 0.93 mg/ml per year; p = 0.015) and drug holiday (- 1.58 mg/ml per year; p < 0.001). Teriparatide was estimated to increase trabecular vBMD by 4.27 mg/ml per year (p = 0.018). Patients receiving denosumab showed a statistically non-significant decrease in trabecular vBMD (- 0.44 mg/ml per year; p = 0.099). Compared to non-treated patients, pharmacological therapy had positive effects on trabecular vBMD (1.35 mg/ml; p = 0.001, 1.43 mg/ml; p = 0.004, 1.91 mg/ml; p < 0.001, and 6.63 mg/ml; p < 0.001 per year for oral bisphosphonates, intravenous bisphosphonates, denosumab, and teriparatide, respectively). CONCLUSION: An increase in trabecular vBMD by QCT was not detected with antiresorptive agents. Patients treated with teriparatide showed increasing trabecular vBMD. Non-treatment led to a larger decrease in trabecular vBMD than pharmacological therapy.

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

INTRODUCTION: 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. MATERIALS AND METHODS: 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 6 months after chemotherapy. The primary endpoint was the change in total volumetric BMD at the distal tibia and radius. RESULTS: Eighteen women were included in the study (median age: 57 years; range: 55-62 years). At 6 months 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. CONCLUSION: Postmenopausal women undergoing chemotherapy for early breast cancer experienced significant BMD deterioration in weight-bearing bone, which was further reduced 6 months after chemotherapy.

The effect of forearm rotation on the bone mineral density measurements of the distal radius.

INTRODUCTION: Forearm dual-energy X-ray absorptiometry (DXA) is often performed in clinics where central DXA is unavailable. Accurate bone mineral density (BMD) measurement is crucial for clinical assessment. Forearm rotation can affect BMD measurements, but this effect remains uncertain. Thus, we aimed to conduct a simulation study using CT images to clarify the effect of forearm rotation on BMD measurements. MATERIALS AND METHODS: Forearm CT images of 60 women were analyzed. BMD was measured at the total, ultra-distal (UD), mid-distal (MD), and distal 33% radius regions with the radius located at the neutral position using digitally reconstructed radiographs generated from CT images. Then, the rotation was altered from - 30° to 30° (supination set as positive) with a one-degree increment, and the percent BMD changes from the neutral position were quantified for all regions at each angle for each patient. RESULTS: The maximum mean BMD changes were 5.8%, 7.0%, 6.2%, and 7.2% for the total, UD, MD, and distal 33% radius regions, respectively. The analysis of the absolute values of the percent BMD changes from the neutral position showed that BMD changes of all patients remained within 2% when the rotation was between - 5° and 7° for the total region, between - 3° and 2° for the UD region, between - 4° and 3° for the MD region, and between - 3° and 1° for the distal 33% radius region. CONCLUSION: Subtle rotational changes affected the BMD measurement of each region. The results showed the importance of forearm positioning when measuring the distal radius BMD.

Vertebral Fracture Risk Thresholds from Phantom-Less Quantitative Computed Tomography-Based Finite Element Modeling Correlate to Phantom-Based Outcomes.

INTRODUCTION: Osteoporosis indicates weakened bones and heightened fracture susceptibility due to diminished bone quality. Dual-energy x-ray absorptiometry is unable to assess bone strength. Volumetric bone mineral density (vBMD) from quantitative computed tomography (QCT) has been used to establish guidelines as equivalent measurements for osteoporosis. QCT-based finite element analysis (FEA) has been implemented using calibration phantoms to establish bone strength thresholds based on the established vBMD. The primary aim was to validate vertebral failure load thresholds using a phantom-less approach with previously established thresholds, advancing a phantom-free approach for fracture risk prediction. METHODOLOGY: A controlled cohort of 108 subjects (68 females) was used to validate sex-specific vertebral fracture load thresholds for normal, osteopenic, and osteoporotic subjects, obtained using a QCT/FEA-based phantom-less calibration approach and two material equations. RESULTS: There were strong prediction correlations between the phantom-less and phantom-based methods (R2: 0.95 and 0.97 for males, and R2: 0.96 and 0.98 for females) based on the two equations. Bland Altman plots and paired t-tests showed no significant differences between methods. Predictions for bone strengths and thresholds using the phantom-less method matched those obtained using the phantom calibration and those previously established, with ≤4500 N (fragile) and ≥6000 N (normal) bone strength in females, and ≤6500 N (fragile) and ≥8500 N (normal) bone strength in males. CONCLUSION: Phantom-less QCT-based FEA can allow for prospective and retrospective studies evaluating incidental vertebral fracture risk along the spine and their association with spine curvature and/or fracture etiology. The findings of this study further supported the application of phantom-less QCT-based FEA modeling to predict vertebral strength, aiding in identifying individuals prone to fractures. This reinforces the rationale for adopting this method as a comprehensive approach in predicting and managing fracture risk.

Fixed and Relative Positioning of Scans for High Resolution Peripheral Quantitative Computed Tomography.

INTRODUCTION: High resolution peripheral quantitative computed tomography (HR-pQCT) imaging protocol requires defining where to position the ∼1 cm thick scan along the bone length. Discrepancies between the use of two positioning methods, the relative and fixed offset, may be problematic in the comparison between studies and participants. This study investigated how bone landmarks scale linearly with length and how this scaling affects both positioning methods aimed at providing a consistent anatomical location for scan acquisition. METHODS: Using CT images of the radius (N = 25) and tibia (N = 42), 10 anatomical landmarks were selected along the bone length. The location of these landmarks was converted to a percent length along the bone, and the variation in their location was evaluated across the dataset. The absolute location of the HR-pQCT scan position using both offset methods was identified for all bones and converted to a percent length position relative to the HR-pQCT reference line for comparison. A secondary analysis of the location of the scan region specifically within the metaphysis was explored at the tibia. RESULTS: The location of landmarks deviated from a linear relationship across the dataset, with a range of 3.6 % at the radius sites, and 4.5 % at the tibia sites. The consequent variation of the position of the scan at the radius was 0.6 % and 0.3 %, and at the tibia 2.4 % and 0.5 %, for the fixed and relative offset, respectively. The position of the metaphyseal junction with the epiphysis relative to the scan position was poorly correlated to bone length, with R2 = 0.06 and 0.37, for the fixed and relative offset respectively. CONCLUSION: The variation of the scan position by either method is negated by the intrinsic variation of the bone anatomy with respect both to total bone length as well as the metaphyseal region. Therefore, there is no clear benefit of either offset method. However, the lack of difference due to the inherent variation in the underlying anatomy implies that it is reasonable to compare studies even if they are using different positioning methods.

Precision Errors and Monitoring Time Interval in Pediatric Muscle Imaging and Neuromuscular Performance Assessment.

OBJECTIVES: To determine precision errors and monitoring time intervals in imaged muscle properties and neuromuscular performance, and to explore growth-related factors associated with precision errors in children. METHODS: We included 35 children (mean age 10.5yrs) in the precision study cohort and 40 children (10.7yrs) in the follow-up study cohort. We assessed forearm and lower leg muscle properties (area, density) with peripheral quantitative computed tomography. We measured neuromuscular performance via maximal pushup, grip force, countermovement and standing long jump force, power, and impulse along with long jump length. We calculated precision errors (root-mean-squared coefficient of variation) from the precision cohort and monitoring time intervals using annual changes from the follow-up cohort. We explored associations between precision errors (coefficient of variation) and maturity, time interval (between repeated measures), and anthropometric changes using Spearman's rank correlation (p<0.05). RESULTS: Muscle measures exhibited precision errors of 1.3-14%. Monitoring time intervals were 1-2.6yrs, except muscle density (>43yrs). We identified only one association between precision errors and maturity (maximal pushup force: rho=-0.349; p=0.046). CONCLUSIONS: Imaging muscle properties and neuromuscular performance measures had precision errors of 1-14% and appeared suitable for follow-up on ~2yr scales (except muscle density). Maximal pushup force appeared more repeatable in mature children.

Predicting Acute Exacerbation Phenotype in Chronic Obstructive Pulmonary Disease Patients Using VGG-16 Deep Learning.

INTRODUCTION: Exacerbations of chronic obstructive pulmonary disease (COPD) have a significant impact on hospitalizations, morbidity, and mortality of patients. This study aimed to develop a model for predicting acute exacerbation in COPD patients (AECOPD) based on deep-learning (DL) features. METHODS: We performed a retrospective study on 219 patients with COPD who underwent inspiratory and expiratory HRCT scans. By recording the acute respiratory events of the previous year, these patients were further divided into non-AECOPD group and AECOPD group according to the presence of acute exacerbation events. Sixty-nine quantitative CT (QCT) parameters of emphysema and airway were calculated by NeuLungCARE software, and 2,000 DL features were extracted by VGG-16 method. The logistic regression method was employed to identify AECOPD patients, and 29 patients of external validation cohort were used to access the robustness of the results. RESULTS: The model 3-B achieved an area under the receiver operating characteristic curve (AUC) of 0.933 and 0.865 in the testing cohort and external validation cohort, respectively. Model 3-I obtained AUC of 0.895 in the testing cohort and AUC of 0.774 in the external validation cohort. Model 7-B combined clinical characteristics, QCT parameters, and DL features achieved the best performance with an AUC of 0.979 in the testing cohort and demonstrating robust predictability with an AUC of 0.932 in the external validation cohort. Likewise, model 7-I achieved an AUC of 0.938 and 0.872 in the testing cohort and external validation cohort, respectively. CONCLUSIONS: DL features extracted from HRCT scans can effectively predict acute exacerbation phenotype in COPD patients.

Assessment of whole-body and regional body fat using abdominal quantitative computed tomography in Chinese women and men.

BACKGROUND: Being overweight or obese has become a serious public health concern, and accurate assessment of body composition is particularly important. More precise indicators of body fat composition include visceral adipose tissue (VAT) mass and total body fat percentage (TBF%). Study objectives included examining the relationships between abdominal fat mass, measured by quantitative computed tomography (QCT), and the whole-body and regional fat masses, measured by dual energy X-ray absorptiometry (DXA), as well as to derive equations for the prediction of TBF% using data obtained from multiple QCT slices. METHODS: Whole-body and regional fat percentage were quantified using DXA in Chinese males (n = 68) and females (n = 71) between the ages of 24 and 88. All the participants also underwent abdominal QCT measurement, and their VAT mass and visceral fat volume (VFV) were assessed using QCT and DXA, respectively. RESULTS: DXA-derived TBF% closely correlated with QCT abdominal fat percentage (r = 0.89-0.93 in men and 0.76-0.88 in women). Stepwise regression showed that single-slice QCT data were the best predictors of DXA-derived TBF%, DXA android fat percentage and DXA gynoid fat percentage. Cross-validation analysis showed that TBF% and android fat percentage could be accurately predicted using QCT data in both sexes. There were close correlations between QCT-derived and DXA-derived VFV (r = 0.97 in men and 0.93 in women). CONCLUSION: Clinicians can assess the TBF% and android and gynoid fat percentages of Chinese women and men by analysing existing abdominal CT-derived data using the QCT technique.

Bone mineral density in lower thoracic vertebra for osteoporosis diagnosis in older adults during CT lung cancer screening.

BACKGROUND: Quantitative computed tomography (QCT)-based lumbar bone mineral density (LBMD) has been used to diagnose osteoporosis. This study explored the value of lower thoracic BMD (TBMD) in diagnosing osteoporosis in older adults during CT lung cancer screening. METHODS: This study included 751 subjects who underwent QCT scans with both LBMD and TBMD. 141 of them was selected for a validation. Osteoporosis was diagnosed based on LBMD using the ACR criteria (gold standard). TBMD thresholds were obtained using receiver operating characteristic curve. TBMD was also translated into LBMD (TTBMD) and osteoporosis was defined based on TTBMD using ACR criteria. The performance of TBMD and TTBMD in identifying osteoporosis was determined by Kappa test. The associations between TBMD- and TTBMD-based osteoporosis and fracture were tested in 227 subjects with followed up status of spine fracture. RESULTS: The performance of TBMD in identifying osteoporosis was low (kappa = 0.66) if using the ACR criteria. Two thresholds of TBMD for identifying osteopenia (128 mg/cm3) and osteoporosis (91 mg/cm3) were obtained with areas under the curve of 0.97 and 0.99, respectively. The performance of the identification of osteoporosis/osteopenia using the two thresholds or TTBMD both had good agreement with the gold standard (kappa = 0.78, 0.86). Similar results were observed in validation population. Osteoporosis identified using the thresholds (adjusted hazard ratio (HR) = 18.72, 95% confidence interval (CI): 5.13-68.36) or TTBMD (adjusted HR = 10.28, 95% CI: 4.22-25.08) were also associated with fractures. CONCLUSION: Calculating the threshold of TBMD or normalizing TBMD to LBMD are both useful in identifying osteoporosis in older adults during CT lung cancer screening.

Early bone loss in patients with obstructive sleep apnea: a cross-sectional study.

BACKGROUND: Obstructive sleep apnea (OSA) and osteoporosis are both prevalent diseases with shared pathophysiological mechanisms and risk factors. However, the association between the two diseases is seldom studied. This study aimed to identify the link between OSA and bone metabolism. METHODS: Male participants aged 30-59-years who visited the sleep clinic were continuously recruited. Polysomnography was used to evaluate sleep and respiratory conditions. Blood samples were collected to detect metabolic, inflammatory and bone turnover indicators. High-resolution peripheral quantitative computer tomography was used to measure the non-dominant lateral radius and tibia. RESULTS: Ninety subjects were recruited. The cortical area (Ct.Ar) of tibia of the severe OSA group was significantly higher than that of the mild and moderate OSA groups (P = 0.06 and P = 0.048). There were significant differences between the four groups in terms of total volumetric bone mineral density (vBMD) (F = 2.990, P = 0.035), meta trabecular vBMD (F = 3.696, P = 0.015), trabecular thickness (Tb.Th) (F = 7.060, P = 0.000) and cortical thickness (Ct.Th) (F = 4.959, P = 0.003). The mean values of the OSA groups were lower than control group. Hypopnea index and percentage of total sleep time with SpO2 < 90% were both positively correlated with alkaline phosphatase (R = 0.213, P = 0.044; R = 0.212, P = 0.045). Sleep efficiency was correlated with multiple indicators of the radius. CONCLUSIONS: In non-elderly male populations, OSA patients tended to have lower vBMD, Tb.Th and Ct.Th than non-OSA patients. The negative effect of OSA may mainly affect the osteogenesis process, and is presumed to be related to sleep-related hypoxemia and sleep efficiency.

Osteoporosis screening using QCT-based cutoff value of Hounsfield units in patients with degenerative lumbar diseases.

PURPOSE: In patients with degenerative lumbar diseases, we aimed to establish the cutoff value of Hounsfield units (HU) for osteoporosis screening on the basis of the relationship between computed tomography (CT) HU value and volume bone mineral density (BMD) measured by quantitative computed tomography (QCT). METHODS: A total of 136 patients aged ≥ 50 years with degenerative lumbar diseases were retrospectively included. Their QCT-BMD of L1-2 were recorded, and the CT values of L1-2 were measured with the same CT images of QCT. The degree of bone loss was evaluated with the criteria based on QCT-BMD: cutoff value of 80 mg/cm3 for osteoporosis and cutoff value of 120 mg/cm3 for osteopenia. The cutoff of CT value was acquired according to the linear regression equation between CT value and QCT-BMD. RESULTS: The rate of osteoporosis, osteopenia, normal BMD was 33.8% (46/136), 51.5% (70/136), and 14.7% (20/136), respectively. The Pearson correlation coefficients between CT value and QCT-BMD were over 0.9 (P < 0.05). The cutoff of average CT value of L1-2 was calculated and adjusted to 110HU for osteoporosis and 160HU for osteopenia according the equation: average QCT-BMD of L1-2 = 0.76 âœ• average CT value of L1-2-0.46 (R2 = 0.931, P < 0.001). Cutoff value of 110HU was 91.2% (42/46) sensitive and 88.9% (80/90) specific for identifying osteoporosis. The cutoff value of 160HU was 95.0% (19/20) sensitive and 96.6% (112/116) specific for distinguishing normal BMD from abnormal BMD (osteoporosis and osteopenia). CONCLUSION: The CT value is effective in osteoporosis screening, and the QCT-based cutoff value is 110 HU for osteoporosis and 160 HU for osteopenia in the patients with degenerative lumbar disease.

Sigmoidal relationship between liver fat content and nonalcoholic fatty liver disease in Chinese adults.

PURPOSE: To explore the relationship between liver fat content (LFC) and nonalcoholic fatty liver disease (NAFLD) and determine the new threshold of LFC to diagnose NAFLD. METHODS: The data from questionnaire survey, general physical examination, laboratory examination, and image examination were collected. Multivariate regression analysis, receiver operating characteristic curve analysis, smooth curve fitting, and threshold effect analysis were performed using the R software to investigate the relationship between LFC and NAFLD and to identify the new threshold of LFC to diagnose NAFLD. RESULTS: The prevalence of NAFLD was 30.42%, with a significantly higher prevalence in men than in women. Regression analyses demonstrated that LFC odds ratio [95% confidence interval (CI)] was 1.28 (95% CI: 1.24-1.31) in fully-adjust model. Analysis of the LFC quartile, with Q1 as a reference, revealed that the odds ratios of NAFLD were 1.47 (95% CI: 1.08-1.99), 2.29 (95% CI: 1.72-3.06), and 10.02 (95% CI: 7.45-13.47) for Q2, Q3, and Q4 groups, respectively. Smooth curve fitting and threshold effect analysis displayed a nonlinear relationship between LFC and NAFLD, and the threshold was 4.5%. The receiver operating characteristic curve indicated that when LFC was 4.5%, the area under curve (95% CI) was 0.80 (0.79-0.82), and the sensitivity and specificity of LFC in diagnosing NAFLD were 0.64% and 0.82%, respectively. CONCLUSION: The relationship between LFC and NAFLD was sigmoidal, with an inflection point of 4.5%.

Micronutrient Status During Military Training and Associations With Musculoskeletal Health, Injury, and Readiness Outcomes.

OBJECTIVE: Micronutrient status, specifically vitamin D and iron, represent modifiable factors for optimizing military readiness. The primary purpose of this investigation was to determine associations between micronutrient deficiency (i.e., iron status and 25-hydroxy-vitamin D [25(OH)D]) and operationally relevant outcomes (i.e., skeletal health, musculoskeletal injury) at baseline and post-10 weeks of arduous military training. METHODS: A total of 227 (177 men, 50 women) Marine Officer Candidates School (OCS) candidates who completed OCS training with complete data sets were included in this analysis. Vitamin D and iron status indicators were collected at two timepoints, pre (baseline) and post OCS. Musculoskeletal outcomes at the mid- and proximal tibial diaphysis were assessed via peripheral quantitative computed tomography. RESULTS: Micronutrient status declined following OCS training in men and women and was associated with musculoskeletal outcomes including greater bone strength (strength strain index) at the mid-diaphysis site in those with optimal status (M = 38.26 mm3, SE = 15.59) versus those without (M = -8.03 mm3, SE = 17.27). In women (p = .037), endosteal circumference was greater in the deficient group (M = 53.26 mm, SE = 1.19) compared with the optimal group (M = 49.47 mm, SE = 1.31) at the proximal diaphysis. In men, greater baseline hepcidin concentrations were associated with an increased likelihood of suffering musculoskeletal injury during training. CONCLUSIONS: Vitamin D and iron status declined over the course of training, suggesting impaired micronutrient status. Differences in musculoskeletal outcomes by micronutrient group suggests optimal vitamin D and ferritin concentrations may exert beneficial effects on bone fatigability and fracture reduction during military training.