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Background: Standardized uptake value (SUV) normalized by lean body mass ([LBM] SUL) is recommended as metric by PERCIST 1.0. The James predictive equation (PE) is a frequently used formula for LBM estimation, but may cause substantial error for an individual. The purpose of this study was to introduce a novel and reliable method for estimating LBM by limited-coverage (LC) CT images from PET/CT examinations and test its validity, then to analyse whether SUV normalised by LC-based LBM could change the PERCIST 1.0 response classifications, based on LBM estimated by the James PE. Methods: First, 199 patients who received whole-body PET/CT examinations were retrospectively retrieved. A patient-specific LBM equation was developed based on the relationship between LC fat volumes (FVLC) and whole-body fat mass (FMWB). This equation was cross-validated with an independent sample of 97 patients who also received whole-body PET/CT examinations. Its results were compared with the measurement of LBM from whole-body CT (reference standard) and the results of the James PE. Then, 241 patients with solid tumours who underwent PET/CT examinations before and after treatment were retrospectively retrieved. The treatment responses were evaluated according to the PE-based and LC-based PERCIST 1.0. Concordance between them was assessed using Cohen's κ coefficient and Wilcoxon's signed-ranks test. The impact of differing LBM algorithms on PERCIST 1.0 classification was evaluated. Results: The FVLC were significantly correlated with the FMWB (r=0.977). Furthermore, the results of LBM measurement evaluated with LC images were much closer to the reference standard than those obtained by the James PE. The PE-based and LC-based PERCIST 1.0 classifications were discordant in 27 patients (11.2%; κ = 0.823, P=0.837). These discordant patients' percentage changes of peak SUL (SULpeak) were all in the interval above or below 10% from the threshold (±30%), accounting for 43.5% (27/62) of total patients in this region. The degree of variability is related to changes in LBM before and after treatment. Conclusions: LBM algorithm-dependent variability in PERCIST 1.0 classification is a notable issue. SUV normalised by LC-based LBM could change PERCIST 1.0 response classifications based on LBM estimated by the James PE, especially for patients with a percentage variation of SULpeak close to the threshold. [ABSTRACT FROM AUTHOR]

Objective: Visceral adipose tissue (VAT) is becoming a recognized cardiovascular (CV) risk factor. This study aimed to evaluate body composition, especially VAT, in systemic lupus erythematosus (SLE) and to explore the association between VAT and SLE disease-related factors. Method: Ninety-eight inpatients with SLE and 108 age- and body mass index (BMI)–matched healthy controls were included. Demographic and clinical parameters were recorded. The VAT was measured by dual-energy x-ray absorptiometry. Result: The mean age and disease duration of patients were 46.4 ± 13.0 years and 8.0 ± 7.0 years, respectively. Patients with SLE had higher VAT volume (p = 0.0015) and mass (p = 0.0017) than controls, especially in premenopausal and postmenopausal groups. The subanalysis of subjects with BMI less than 25 kg/m2 indicated that patients had lower lean mass (p = 0.0005), fat-free mass (p = 0.0005), and fat-free mass index (p = 0.0001), but increased adiposity distribution than controls, including VAT volume and mass. However, overweight/obese patients had similar body composition with controls. The VAT volume correlated with BMI, age, menopausal status, hypertension, uric acid, creatinine, non-high-density lipoprotein cholesterol, and triglyceride in both groups. In the patient group, the VAT volume correlated with disease duration, Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index (SLICC/ACR-DI), and low serum complement, but not with SLEDAI and glucocorticoid dose. Conclusion: This study suggested that SLE patients had some traditional CV risk factors such as altered body composition and increased VAT. The higher VAT in patients with SLE was associated with traditional cardiometabolic risks, which may contribute to CV events in SLE populations. Key Points • Patients with SLE had increased VAT volume and mass than controls. • The VAT volume correlated with traditional cardiometabolic risk factors. • In SLE patient group, the VAT volume correlated with disease duration, SLICC/ACR-DI, and low serum complementC3/C4, but not with SLEDAI and glucocorticoid dose. [ABSTRACT FROM AUTHOR]

Measurements of body composition by dual-energy X-ray absorptiometry (DXA) have evident value in evaluating skeletal and muscular status in growing children and adolescents. This study aimed to generate age-related trends for body composition in Chinese children and adolescents, and to establish gender-specific reference percentile curves for the assessment of muscle-bone status. A total of 1541 Chinese children and adolescents aged from 5 to 19 years were recruited from southern China. Bone mineral content (BMC), lean mass (LM) and fat mass (FM) were measured for total body and total body less head (TBLH). After 14 years, total body LM was significantly higher in boys than girls ( p < 0.001). However, total body FM was significantly higher in girls than boys in age groups 13-19 years ( p < 0.01). Both LM and FM were consistent independent predictors of total body and subcranial bone mass in both sexes, even after adjustment for the well-known predictors of BMC. The results of multiple linear regression identified LM as the stronger predictor of total body and subcranial skeleton BMC while the fat mass contributed less. For all the subjects, significant positive correlations were observed between total body LM, height, total body BMC and subcranial BMC ( p < 0.01). Subcranial BMC had a better correlation with LM than total body BMC. We have also presented gender-specific percentile curves for LM-for-height and BMC-for-LM which could be used to evaluate and follow various pediatric disorders with skeletal manifestations in this population. [ABSTRACT FROM AUTHOR]

We investigated age-related changes in estimated bone strength and cross-sectional structure of the femoral neck (FN) in mainland Chinese men and women (according to age and sex) using dual-energy X-ray absorptiometry (DXA). A total of 3855 healthy adults (2713 women, 1142 men; ages 25–91 years) were analyzed by FN bone mineral density (BMD) assessment and hip structural/strength analysis (HSA), including cross-sectional moment of inertia (CSMI), cross-sectional area (CSA), section modulus (Z), periosteal diameter (PD), endocortical diameter (ED), and cortical thickness (CT) using DXA. HSA differences between age and sex groups were adjusted for body weight, height and FN BMD. Trends according to age were estimated by linear regression analysis. There was no inverse correlation between HSA parameters and age in young adults. Some HSA parameters (CSMI, CSA, Z, CT) decreased significantly with age, whereas PD and ED increased significantly. Older adults had less estimated bone strength and CT and higher PD and ED ( p < 0.05) than young adults. Men had greater increases in PD and ED than women across all ages. FN strength decreases with age in both sexes, caused by FN cross-sectional structural deterioration. Indirect comparison of our data with those from other populations showed less age-related FN periosteal apposition in Chinese than Caucasian men, but similar amounts in women. This may partly explain different male/female hip fracture rates among ethnic groups. Chinese men have more structural disadvantages regarding FN geometry during aging than Caucasian men, possibly conferring added susceptibility to hip fracture. [ABSTRACT FROM AUTHOR]