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Osteoporosis is characterized by decreased bone strength and increased fracture risk. The most serious consequence of osteoporosis is fracture, which commonly occurs in vertebrae. Accurate assessment of fracture risk at an earlier stage is the key to identify high-risk population and further prevent osteoporotic fracture. Currently, clinical assessment of vertebral fracture risk mainly relies on measurement of bone mineral density (BMD) based on dual energy X-ray absorptiometry ( DXA) or quantitative computed tomography ( QCT). However, they cannot fully reflect bone strength and resistance to fracture, and it is hard to achieve an accurate assessment. Biomechanical CT (BCT) technology, based on CT digital modeling and finite element analysis, aims at non-invasive calculation of individual bone strength, bridging the gap between biomechanics and clinical evaluation of fracture risk. In vitro mechanical experiment of vertebrae has proved that BCT is more accurate than BMD in evaluating vertebral fracture strength. Clinical studies have also shown that BCT is superior to DXA inidentifying existing fractures and predicting new fractures. In this article, the implementation process of the BCT technology was introduced, as well as critical parameters during each step affecting its result . The research progress of the BCT technique for in vitro validation and in vivo assessment of vertebral fracture risk was also summarized, with the aim to promote the application of BCT technology in clinical assessment of vertebral fracture risk for the Chinese people.
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Objective:To explore the optimal keV value of the virtual monoenergetic image (VMI) for displaying the osteosarcoma by using the dual-layer spectral detector CT and to evaluate its application value in determining the extent of intramedullary invasion of osteosarcoma.Methods:From August 2021 to August 2022, 57 patients with conventional osteosarcoma of long bone confirmed by biopsy in Beijing Jishuitan Hospital, Capital Medical University were retrospectively analyzed. All patients completed dual-layer spectral CT enhanced examination before limb salvage surgery, and tumor segment resection specimens were obtained after surgery. Conventional 120 kVp image and VMI of 40, 50, 60, 70 and 80 keV were obtained by spectral CT examination, and the CT values of tumors, image noise were measured and the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the corresponding images were calculated. The objective evaluation among the six groups of images were assessed with the Friedman test, and then determined the optimal keV value. The maximum distance between the intramedullary boundary of osteosarcoma and the adjacent articular surfaces was measured on the best keV VMI and the tumor segment resection specimens. The Wilcoxon signed rank test was used to find the differences and the Spearman correlation analysis was used to evaluate the correlation between the distance measured from the best keV VMI and the specimens.Results:There were significant differences in CT value, image noise, SNR and CNR between 40-80 keV VMI and 120 kVp conventional CT images ( P<0.05). The CT value, SNR and CNR of 40 and 50 keV VMI were better than 120 kVp ( P<0.001). The 50 keV VMI was chosen as the best keV VMI to measure the intramedullary extent of osteosarcoma. The distance measured from 50 keV VMI was 103.9 (80.4, 131.4) mm, while the distance measured from specimens was 113.5 (94.0, 142.0) mm, and the difference was statistically significant ( Z=-5.76, P<0.001). The 50 keV VMI measurements in 51 patients were smaller than the gross specimens, which underestimated the tumor intramedullary extent, with the difference was 11.1 (6.6, 13.8) mm. The Spearman correlation analysis demonstrated a high positive correlation of distance measured on gross specimens with the 50 keV VMI ( r s=0.960, P<0.001). Conclusions:Dual-layer spectral detector CT with 50 keV VMI is the best image to show the limb osteosarcoma. Compared with gross specimens, the distance measured from CT underestimated the intramedullary invasion range of limb osteosarcoma about 10 mm, but the two show a good correlation.
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Objective:To explore the accuracy of artificial intelligence (AI) system based on deep learning in evaluating bone age of children with abnormal growth and development.Methods:The positive X-ray films of the left wrist of children with abnormal growth and development who were treated at the Affiliated Hospital of Guizhou Medical University from January 2020 to December 2021 were collected retrospectively. A total of 717 children were collected, including 266 males and 451 females, aged 2-18 (11±3) years. Based on Tanner Whitehouse 3 (TW 3)-RUS (radius, ulna, short bone) and TW3-Carpal (carpal bone) method, bone age was measured by 3 senior radiologists, and the mean value was taken as reference standard. The bone ages were independently evaluated by the AI system (Dr.Wise bone age prediction software) and two junior radiologists (physicians 1 and 2). The accuracy within 0.5 year, the accuracy within 1 year, the mean absolute error (MAE) and the root mean square error (RMSE) between the evaluation results and the reference standard were analyzed. Paired sample t-test was used to compare MAE between AI system and junior physicians. Intraclass correlation coefficient (ICC) was used to evaluate the consistency between AI system, junior physician and reference standard. The Bland-Altman diagram was drawn and the 95% consistency limit was calculated between AI system and reference standard. Results:For TW3-RUS bone age, compared with the reference standard, the accuracy within 0.5 year of AI system, physician 1 and physician 2 was 75.3% (540/717), 62.1% (445/717) and 66.2% (475/717), respectively. The accuracy within 1 year was 96.9% (695/717), 86.3% (619/717) and 89.1% (639/717), respectively. MAE was 0.360, 0.565 and 0.496 years, and RMSE was 0.469, 0.634 and 0.572 years, respectively. For TW3-Carpal bone age, compared with the reference standard, the accuracy within 0.5 year of AI system, physician 1 and physician 2 was 80.9% (580/717), 65.1% (467/717) and 71.7% (514/717), respectively. The accuracy within 1 year was 96.0% (688/717), 87.3% (626/717) and 90.4% (648/717), respectively. MAE was 0.330, 0.527 and 0.455 years, and RMSE was 0.458, 0.612, 0.538 years, respectively. Based on TW3-RUS and TW3-Carpal bone age, the MAE of AI system were lower than those of physician 1 and physician 2, and the differences were statistically significant ( P all<0.001). The evaluation results of AI, physician 1 and physician 2 were in good agreement with the reference standard (ICC all>0.950). The Bland-Altman analysis showed that the 95% agreement limits of AI system for assessing TW3-RUS and TW3-Carpal bone age were -0.75-1.02 years and-0.86-0.91 years, respectively. Conclusion:The accuracy of AI system in evaluating the bone age of children with abnormal growth and development is close to that of senior doctors, better than that of junior doctors, and in good agreement with senior doctors.
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Objective:To evaluate the applicability of bone age (BA) assessment methods and to investigate the difference between BA and chronological age (CA) based on the data of children in rural areas of Beijing.Methods:A total of 412 healthy children (226 boys, 186 girls) with the age 8.6 (6.8, 10.3) years old were included in this study. The data of the prospective study were from a subgroup of the project "National Nutrition and Health Systematic Survey for 0-18 Years Old Children in China", which included children with age of 3-12 years old in Beijing rural areas. The non-dominant hand-wrist radiographs of all participants were obtained in April 2021. The Dr.Wise BA detection and analysis system was used to assess the BA according to the Tanner Whitehouse 3 (TW3) radius-ulna-short bone score (TW3-RUS), TW3 carpal bone score (TW3-Carpal), China-05 TW3-Chinese RUS (TW3-C RUS), China-05 TW3-Chinese carpal (TW3-C Carpal), and Greulich-Pyle (G-P) standards. The cases were stratified by the sex and different CA in the statistical analysis. The estimated BA obtained using different methods were compared with the CA using Wilcoxon signed ranks test.Results:The sex-stratified results showed that no significant difference was found between the estimated BA using G-P standards and CA in boys ( Z=-0.694, P=0.488), while all the other estimated BA results were statistically significantly higher than CA ( P<0.05). Stratified by both sex and CA, the estimated BA using G-P standards in 4-6 years old boy groups, as well as the estimated BA using TW3-Carpal and TW3-C Carpal standards in 11-12 years old girl groups were lower than CA, while in the other groups, the estimated BA were higher than CA. Conclusions:There were varying degrees of deviations in the BA estimations using TW3, China 05, and G-P methods for children in rural areas of Beijing. It is imperative to establish a new standard for the BA evaluation of the contemporary Chinese children.
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Objective:To report the sampling study design and radiography protocol of a large-sample investigation on skeletal maturation of 3 to 18-year-old children in China.Methods:Multi-stage stratified random sampling was employed in this study. Two provinces, municipalities, or autonomous regions were randomly selected from each of the seven regions of China, including Northeast China, Northwest China, North China, Central China, East China, Southwest China, and South China. Then one rural and one urban investigation site were randomly selected from each province, municipality, or autonomous region. In total 28 sites were included. Among those sites, four residential districts were randomly selected from each urban site, and four townships from each rural site. For each residential district or township, 1-4 kindergartens, primary schools, and middle schools were chosen. Random cluster sampling was used to extract 3-<6-year-old children in kindergartens, and 6-18-year-old children in primary schools and middle schools. The investigation on skeletal maturation was sampled proportionate to the sampling of the whole study. The estimated simple size was 780 for each site, and 21 840 for all 28 sites in total. There were six groups of 3-<6-year-old children classified at 0.5-year intervals, and 12 groups of 6-18-year-old children classified at 1-year intervals. Posteroanterior position radiography of the left hand and wrist was achieved for all subjects.Results:The study was performed from August 26, 2019 to October 16, 2021. In total, 20 444 children received posteroanterior position radiography of the left hand and wrist, including 10 196 males and 10 248 females, 9 711 urban and 10 733 rural, respectively. The 3-<6-year-old group included 1 611 (male 819, female 792) subjects, and the 6 to 18-year-old group included 18 833 (male 9 377, female 9 456) subjects.Conclusion:This nationwide investigation on skeletal maturation of 3 to 18-year-old children in seven regions of China was successfully preformed. The results of this study can provide an important reference for establishing the current evaluation criteria of bone age in Chinese children and adolescents.
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Objective:To explore the value of iterative decomposition of water and fat with asymmetry and least squares estimation-quantitative fat imaging (IDEAL-IQ) in quantitative evaluation of thigh muscle fat content and its correlation with muscle strength in middle-aged and elderly volunteers.Methods:From December 2020 to April 2021, 30 volunteers aged 45 to 70 were recruited prospectively, including 15 males and 15 females with 52.5 (49.0, 56.3) years old. All subjects were scanned at 3.0 T MR, including axial T 1WI, IDEAL-IQ and coronal T 2WI of the left thigh. The region of interest of the knee extensors (quadriceps femoris) and knee flexors (hamstrings) in the left mid-thigh were delineated, and muscle cross-sectional area (CSA), skeletal muscle index (SMI), intermuscular fat fraction (FF) and intramuscular FF were obtained. In addition, isokinetic muscle strength measurement was performed on the left knee joint of all subjects at angular speeds of 60°/s and 180°/s to obtain peak torque (PT) and total work (TW) of knee flexors and extensors. Independent sample t-test, paired t-test or Mann-Whitney U test were used to compare the differences of CSA, SMI, intermuscular FF, intramuscular FF, PT and TW between different genders and muscle groups. Pearson or Spearman correlation analysis, and multiple linear regression analysis were used to analyze the correlation between CSA, SMI, intermuscular FF, intramuscular FF and PT, TW of thigh muscles. Results:The CSA, PT and TW of thighs in males were higher than those in females ( P<0.05), while the intermuscular FF in males was lower than that in females ( P=0.005). The CSA, SMI and PT of the thigh extensors were higher than those of the flexors ( P<0.001), while the intramuscular FF and intermuscular FF were lower than those of the flexors ( P<0.001). Intramuscular FF of flexors and extensors were moderately negatively correlated with PT ( r=-0.635, P<0.001; r=-0.546, P<0.001), and highly, moderately negatively correlated with TW ( r=-0.718, P<0.001; r=-0.616, P<0.001). Intermuscular FF of flexors and extensors were moderately negatively correlated with PT ( r=-0.519, P=0.003; r=-0.443, P=0.014), and negatively correlated with TW ( r=-0.363, P=0.049; r=-0.552, P=0.002). There was no significant correlation between CSA, SMI and PT, TW in flexors and extensors of thigh ( P>0.05). Multiple linear regression analysis showed that intramuscular FF was still significantly correlated with PT and TW of flexors and extensors (flexors: R 2adj=0.505, P=0.001; R 2adj=0.540, P<0.001; extensors: R 2adj=0.351, P=0.006; R 2adj=0.470, P=0.002). Conclusion:FF based on IDEAL-IQ technology can accurately quantify the intramuscular and intermuscular fat content of thighs, and there are negative correlations between intramuscular FF, intermuscular FF and isokinetic muscle strength measurements including PT and TW. Among them, intramuscular FF is more significant.
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Objective:The aim of this study was to explore the associations of muscle size and density with handgrip strength(HGS)and the Timed Up and Go(TUG)test.Methods:Totally 301 participants living in the Xinjiekou community near Beijing Jishuitan Hospital were recruited for CT imaging of the hip and a 1-cm slice of the mid-thigh.The cross-sectional area and density of the gluteus maximus and the mid-thigh muscles were estimated by the Osirix viewer based on CT images.HGS and TUG were also performed in these subjects.Logistic regression analysis was used to evaluate the correlations of muscle density and size with TUG and grip strength.Results:In women, after adjustment for age and BMI, the density of the gluteus maximus was negatively correlated with TUG( P trend=0.0366), while the size of the gluteus maximus and the mid-thigh muscles was not correlated with TUG.In men, the density or size of these muscles was not correlated with TUG.After adjustment for age and BMI, the density of the gluteus maximus was positively correlated with grip strength( P trend=0.0334)and the size of the mid-thigh muscles was also positively correlated with grip strength( P trend=0.0155)in men, but they were not correlated with grip strength in women. Conclusions:There were sex differences in the relationship between muscle size or density and grip strength or timed up and go.The density of the gluteus maximus is associated with muscle strength and physical performance while the size of the mid-thigh muscles is correlated with muscle strength.
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Objective:To use quantitative computed tomography (QCT) technology to measure the bone mineral density of the spine of the Chinese healthy population, and to explore its correlation with hemoglobin and serum albumin.Methods:The data in this study came from the China Health Quantitative CT Big Data Project (China Biobank). The spine bone density was measured by using QCT Pro Image Analysis System and all cooperating centers used the European spine phantom (NO.145) for quality control. Total of 50 053 healthy persons who met the criteria for entry were selected as the research subjects. The subjects were divided into 7 groups according to age. The general data, spine bone density, serum albumin, hemoglobin of the subjects were collected. The single-factor analysis of variance, Pearson correlation analysis and multi-classification logistic regression model were applied to analyze the correlation between bone density and hemoglobin and serum albumin.Results:The bone mineral density of healthy people decreased with age ( P<0.05), and there were significant differences in hemoglobin, serum albumin and body mass index (BMI) among different age groups (all P<0.05). Linear correlation analysis showed that there were positive correlation between bone mineral density and hemoglobin in healthy males in different age groups ( r=0.086, 0.101, 0.076, 0.090, 0.072, 0.123, 0.100, all P<0.01). There were negative correlation between bone mineral density and hemoglobin in certain age groups in women (40-49 years group: r=-0.027; 70-79 yearsgroup: r=-0.077; both P<0.05). And corelation were found between bone mineral density and serum levels of albumin in certain age groups of healthy subjects (among men, 30-39 years group: r=-0.048; 40-49 years group, r=-0.027; 70-79 years group, r=-0.051; among women, 30-39 years group: r=-0.044; 40-49 years group, r=-0.042; 50-59 years group, r=-0.086; 70-79 years group, r=-0.070; all P<0.05). After adjusting for age and BMI, the multi-category logistic regression analysis showed that the hemoglobin level was protective factor of normal bone density ( OR=1.022, 95% CI:1.017-1.027) and decreased bone density ( OR=1.012, 95% CI:1.007-1.016) in healthy males, and the serum albumin was risk factor for normal bone density ( OR=0.926, 95% CI:0.905-0.948) and decreased bone density ( OR=1.006, 95% CI:0.951-1.011) in healthy women. Conclusion:There is a correlation between bone mineral density and hemoglobin and serum albumin in Chinese healthy population. Hemoglobin is a protective factor for bone mineral density in men, and serum albumin is a risk factor for bone mineral densityin women.
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Objective:To establish the normal reference value of lumbar bone mineral density (BMD) under quantitative CT (QCT) in Chinese healthy adult females and to explore the regional differences.Methods:Total of 35 431 healthy women who met the inclusion criteria of Chinese health quantitative CT big data program were selected in this study. The BMD of the central plane of L 1 and L 2 vertebrae was measured by Mindways′s QCT system, and the mean value was taken. One-way analysis of variance was used to compare the BMD differences of lumbar vertebrae in women of different ages and regions. The subjects were grouped by an age interval of 10 years, and the level of BMD in different regions of the same age group were compaired. Results:The peak BMD of Chinese healthy adult women appeared in the age group of 20-29 years (Northeast China(183.01±24.58) mg/cm 3, North China (188.93±24.80) mg/cm 3, East China (187.54±27.71) mg/cm 3, South China (186.22±33.72) mg/cm 3, Central China (176.33±24.91) mg/cm 3, Southwest China(182.25±28.00) mg/cm 3), and then it decreased with age. The level of BMD in different regions decreased with the age. Before the age of 70 years, BMD in Central and Southwest China was always at a low level((176.23±24.91) to (90.38±28.12) mg/cm 3, 182.25±28.00 to (88.55±25.68) mg/cm 3), lower than those in Northeast China ((183.01±24.58) to (99.69±27.85) mg/cm 3), North China ((188.93±24.80) to (95.89±26.12) mg/cm 3), East China ((187.54±27.71) to (95.65±27.86) mg/cm 3). After 70 years of age, BMD tended to be the same in different regions ( P>0.05). The BMD values in Central China and Southwest China were similar in the age group of 40-60 years ( P>0.05). The BMD values in the health adult femles in the age group of 60 years in different regions of Chinawere all lower than those of bone mass abnormality (all P<0.05). The detection rate of osteoporosis in females over 50 years was the highest in Southwest China (25.65%) and it was the lowest in North China (17.30%). Conclusions:This study establishes reference values of BMD under QCT in healthy Chinese women, which can be used as a reference basis for identifying women with low BMD who are at risk of osteoporosis. The BMD value is the lowest in Southwest China and the highest in South China.
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Objective:To investigate the normal reference values of spinal bone mineral density measured by quantitative computed tomography (QCT) and the differences of bone mineral density (BMD) in different regions of in Chinese adult males.Methods:Men who underwent low-dose CT lung scan for cancer screening in regions of Northeast, North, East, South, Central and Southwest of China from January 2018 to December 2019 were selected. And the lumbar vertebrae BMD values in the male subjects were measured by the QCT system (Mindways Software, Inc.). The mean BMD values and their decline rates were calculated at an age interval of 10 years, and the prevalence of osteoporosis was calculated according to the American College of Radiology spine QCT osteoporosis diagnostic criteria.Results:A total of 50 682 males with a mean age of (50.22±12.79) years (ranged 20 to 98 years) were included in this study. The peak BMD of (173.11±28.56) mg/cm 3 in the healthy Chinese adult male population appeared in the age group of 20 to 29 years and then declined with age. Before the age of 70 years, the BMD was relatively higher in males in South China, and it was lower in Central China and Southwest China, and it was intermediate in Northeast, North and East of China, with statistically significant differences. There was no significant differences in BMD in the males in the two age groups of 70 to 79 years and 80 and older among the regions in China. The overall decline rate of spinal BMD in Chinese males under QCT was about 46.92% over the lifetime, and it declined obviouslyin the 40-49 age group. The overall prevalence of osteoporosis in Chinese male population aged 50 years and above was approximately 11.42%, with the highest prevalence in Southwest China and Central China (14.72% and 13.87%, respectively) and the lowest in North China and South China (8.53% and 7.71%, respectively). Conclusions:A reference of lumbar spine BMD values for healthy males in China based on QCT is established. BMD values were highest in South China and Lowest in Central China.
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Objective:To describe the baseline characteristics of the subjects enrolled in the China Quantitative CT (QCT) big data program in 2018—2019.Methods:Based on baseline data from the Chinese health big data project from January 2018 to December 2019 from the eligible enrolled population, measurements of bone mineral density (BMD) and visceral adipose tissue (VAT) were performed using Mindways′ QCT Pro Model 4 system. The baseline data of age, gender, regional distribution, height, weight, abdominal circumference, blood pressure, blood routine and blood biochemical tests were analyzed. And the single factor analysis of variance (ANOVA) was used to check the age related trend of BMD and VAT in both genders.Results:After screening the inclusion exclusion criteria and outliers of the main indicators, 86 113 people were enrolled in the project. The enrollment rate was 92.47%, including 35 431 (41.1%) women and 50 682 (58.9%) men, and the ratio of men to women was 1.43. The mean age was (50.3±12.7) years in all the subjects, and it was (50.2±12.8) years and (50.4±12.5) years in men and women, respectively, and there was no statistical difference between the two genders ( P>0.05). Total of 43 833 people were enrolled in east China, it was the largest group by region (50.90%), it was followed by central China (16 434 people, 19.08%), and the number of people enrolled in Northeast China was the lowest (2 914 people, 3.38%). The rate of completing of health information indicators related to the main outcome of the study were all above 70%, and there were significant differences between men and women (all P<0.05). The mean BMD was (139.33±46.76) mg/cm 3 in women, (135.90±36.48) mg/cm 3 in men, which showed a decreasing trend with age in both gender (both P<0.001); the mean intra-abdominal fat area was (116.39±56.23) cm 2 in women, (191.67±77.07) cm 2 in men, and there was an increasing trend with age in both men and women (both P<0.001). Conclusions:There are gender differences in BMD and VAT measured by QCT with different age tendency, and there are gender differences in health information index. Regional factors should also be taken into account for regional differences in the inclusion of data.
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Objective:To investigate the relationship between abdominal visceral adipose tissue (VAT) and cardiometabolic risk (CMR) through quantitative computed tomography (QCT).Methods:The present study included 76226 participants. Abdominal fat areas were measured using the QCT Pro Model 4 system. Cardiometabolic indices were collected, including systolic and diastolic blood pressures, fasting plasma glucose, total cholesterol, triglyceride, and low-density and high-density lipoprotein cholesterols CMR score was the sum of abnormal blood pressure, fasting glucose, triglyceride, and high-density lipoprotein cholesterol. Restricted cubic spline and ordered logistic regression models were applied.Results:The mean age was 50±13 years and the percentage of men was 58.8%. The level of VAT area was higher in men than in women (191.7±77.1 cm 2 vs 116.4±56.2 cm 2, P<0.0001 for all). After adjustment for age, the cardiometabolic indices except high-density lipoprotein cholesterol increased with increasing VAT area. When VAT area was 300 cm 2, age-adjusted odds ratios and 95% confidence intervals of a CMR score ≥ 1 were 14.61 (13.31, 16.04) for men and 5.46 (4.06, 7.36) for women, and the age-adjusted probability of a CMR score ≥ 3 was 31.7% for men and 31.3% for women. Conclusions:QCT-derived VAT is closely related to CMR. The findings suggest that measurement of visceral fat is recommended for the management of abdominal obesity in subjects who agree to undergo lung cancer screening via low-dose CT without additional radiation exposure.
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Objective:To evaluate the precision of quantitative CT (QCT) in measuring fat content of goose liver and to explore the influence of tube voltage on liver fat measurement.Methods:From January to March 2017, 22 Landes geese were selected to establish fatty liver models with overfeeding. The QCT was performed under 2 different tube voltages, 80 and 120 kV. In addition to the voltage, the other scanning parameters were the same. Three ROI were placed in the centre part of the left lobe, upper and lower half of the right lobe on the 3D reconstructed images. The volume percentage of goose liver fat (Fat% QCT) was calculated according to the formula provided by Mindways. Immediately after the QCT examinations, each goose was dissected, and the whole liver was removed. Then samples were taken in the corresponding areas of the ROI by QCT. The fat (triglyceride) content of the samples was measured by the biochemical extraction method. The Spearman correlation tests were used to determine the correlation between the QCT measurements of 80 kV and 120 kV groups and the results of biochemical extraction method. The Wilcoxon signed-rank test was performed to compare Fat% QCT between 80 kV and 120 kV groups. Bland-Altman plots were used to assess agreement between the two groups′ measurements. Results:The Fat% QCT of both 80 kV and 120 kV group positively correlated highly with biochemical extraction ( r s=0.936, P<0.001, r s=0.927, P<0.001) respectively. No statistically significant difference of Fat% QCT was detected between 80 kV and 120 kV group ( Z=-0.141, P=0.888). Bland-Altman analysis showed a small difference of Fat% QCT between the 80 kV and 120 kV group, in which mean values were 0.20%. Conclusions:Using biochemical extracted triglyceride as the reference, under the conditions of low-dose 80 kV and standard 120 kV tube voltages, QCT measurement of fat content is accurate and reliable in goose liver.
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Objective:To evaluate the short-term precision and accuracy of bone mineral density (BMD) measured with quantitative CT (QCT) and dual-energy X-ray absorptiometry (DXA) in multi-centre clinical research with a European spine phantom (ESP).Methods:From January 2016 to April 2020, totally 40 CT scanners (12 Siemens from Germany, 12 Philips from Netherlands, 9 GE from US, 5 Toshiba from Japan, 2 United Imaging from China) and 53 DXA instruments (34 GE Lunar from US, 14 Hologic from US, 5 Medlink from France) used in multi-centre in China were enrolled. The CT equipment came from 31 centers and DXA equipment from 32 centers.Using Mindways QCT software, the ESP was scanned 10 times on each instrument with repositioning using standardized spine protocols with QCT and DXA. The BMD value of the three lumbar vertebrae with low, medium, high density and the mean BMD value were measured. Accuracy was assessed by comparing BMD values measured on each device with the actual value of the phantom. Short-term precision was calculated as the root-mean-square standard deviation (RMS-SD) and root-mean-square standard deviation coefficient of variation (RMS-%CV) for the repeated measurements. The repeated measures variance analysis was used to compare the differences in BMD between different devices.Results:The differences in BMD values were statistically significant among different CT and DXA devices.The ranges of the accuracy measured by different QCT devices were 1.20% to 7.60% for Siemens, -1.83% to 0.20% for Philips, 1.18% to 13.20% for GE, -0.12% to 3.55% for Toshiba, -1.65% to 6.32% for United Imaging, 6.59% to 21.34% for GE Lunar, -6.65% to 5.45% for Hologic, and -6.97% to -0.68% for Medlink, respectively. The RMS-%CV of all vertebral BMD values measured by QCT and DXA ranged from 0.38% to 3.85%. The RMS-SD of QCT was 0.54 to 2.45 mg/cm 3, of DXA was 0.009 to 0.037 g/cm 2. The RMS-%CV values of each vertebral body measured by different QCT and DXA devices decreased with the increase of BMD, while the RMS-SD values showed the opposite tendency. Conclusions:Based on ESP, the QCT and DXA devices have significant differences in lumbar spine BMD measurement. Comparing the measurement results among different devices requires cross-calibration. Overall, the accuracy and short-term precision are within a reasonable range, which can be used for clinical follow-up observation. The short-term precision error and accuracy error range of QCT in evaluating the density of ESP were slightly smaller than those of DXA.
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Objective:To investigate the quantitative relationship between liver fat content and bone mineral density (BMD) in middle-aged and elderly people.Methods:Totally 184 middle-aged and elderly community residents were recruited from March to June 2016, including 68 males and 116 females. MRI mDIXON-Quant and quantitative CT (QCT) examinations were performed to determine the content of liver fat and L1-L3 vertebral BMD. The subjects were divided into four groups according to the quartiles of liver fat content, and the baseline characteristics and other variables of different groups were were identified by using one-way analysis of Variance. The relationship between liver fat content and lumbar vertebral BMD was assessed with Spearman correlation and partial correlation analysis.Result:Subjects with higher hepatic fat content had lower spine BMD and higher body mass index (BMI), waist circumference. Liver fat content was negatively correlated with BMD ( r=-0.203, P=0.003). After age and body weight were controlled, the negative correlation between liver fat content and BMD was still significant ( r=-0.291, P<0.001), in males ( r=-0.283, P=0.021) and in females ( r=-0.210, P=0.025). Conclusion:Liver fat content is negatively correlated with lumbar vertebral BMD in middle-aged and elderly people.
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Objective@#To investigate the quantitative relationship between liver fat content and bone mineral density (BMD) in middle-aged and elderly people.@*Methods@#Totally 184 middle-aged and elderly community residents were recruited from March to June 2016, including 68 males and 116 females. MRI mDIXON-Quant and quantitative CT (QCT) examinations were performed to determine the content of liver fat and L1-L3 vertebral BMD. The subjects were divided into four groups according to the quartiles of liver fat content, and the baseline characteristics and other variables of different groups were were identified by using one-way analysis of Variance. The relationship between liver fat content and lumbar vertebral BMD was assessed with Spearman correlation and partial correlation analysis.@*Result@#Subjects with higher hepatic fat content had lower spine BMD and higher body mass index (BMI), waist circumference. Liver fat content was negatively correlated with BMD (r=-0.203, P=0.003). After age and body weight were controlled, the negative correlation between liver fat content and BMD was still significant (r=-0.291, P<0.001), in males (r=-0.283, P=0.021) and in females (r=-0.210, P=0.025).@*Conclusion@#Liver fat content is negatively correlated with lumbar vertebral BMD in middle-aged and elderly people.
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Objective:To explore the association between body composition and blood pressure by quantitative CT (QCT) in a Shanghai population.Methods:A total of 1 307 participants undergoing low-dose CT lung cancer screening and body composition measurem ents using QCT in our hospital from May to December 2018 were retrospectively enrolled. Body composition, including the abdominal soft tissue area (ASTA), visceral adipose area (VAA), and subcutaneous adipose area (SAA) at the central slice of L2, was measured using QCT. To explore the correlations among body composition and systolic blood pressure, diastolic blood pressure, and hypertension, Pearson’s correlation, multivariate linear regression, and multivariate logistic regression analysis were used. The cut-off value for predicting hypertension was analyzed using the ROC curve.Results:Pearson’s correlation analysis showed that ASTA was negatively correlated with systolic blood pressure and diastolic blood pressure ( r=-0.237- -0.102, P<0.05), while VAA and SAA were positively correlated with systolic blood pressure and diastolic blood pressure (VAA: r=0.359-0.486, SAA: r= 0.088-0.365, P<0.05 ). After adjusting for age, sex, body mass index, and waist circumference, multivariate regression analysis showed that VAA was significantly associated with systolic blood pressure (β= 0.142, P= 0.002), diastolic blood pressure (β= 0.245, P<0.001), and hypertension ( OR=1.005, 95% CI: 1.001-1.008, P=0.01), while ASTA or SAA was not significantly associated with systolic blood pressure, diastolic blood pressure, and hypertension. ROC curve analysis indicated that the cut-off values of VAA at the central slice of L2 for predicting hypertension in males and females were 201.89 cm 2 and 136.01 cm 2, respectively. Conclusion:Visceral adiposity was found to be closely related to hypertension. For hypertension management, early screening and strengthening of prevention and management methods are needed for people with abnormally increased visceral adiposity.
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Objective@#To evaluate the application value of quantitative computed tomography for evaluation of changes in abdominal fat after laparoscopic Roux-en-Y gastric bypass in obese patients.@*Methods@#The retrospective and descriptive study was conducted. The clinical data of 52 obese patients who underwent laparoscopic Roux-en-Y gastric bypass in the Third Medical Center of Chinese PLA General Hospital from March 2011 to February 2012 were collected. There were 24 males and 28 females, aged (43±9)years, with the range of 23-62 years. All the 52 patients underwent laparoscopic Roux-en-Y gastric bypass. Observation indicators: (1) surgical and postoperative conditions; (2) changes in anthropometric indices; (3) follow-up. Follow-up using outpatient examination was performed to detect complications of patients at 1, 3, 6, 12 months after surgery up to February 2013. Measurement data with normal distribution were represented as Mean±SD, repeated measurement data were analyzed using repeated ANOVA. Count data were represented as absolute numbers.@*Results@#(1) Surgical and postoperative conditions: all the patients underwent laparoscopic Roux-en-Y gastric bypass successfully, without conversion to open surgery. The volume of intraoperative blood loss, operation time, and duration of hospital stay were (25±11)mL, (78±14)minutes, and (11±2)days. (2) Changes in anthropometric indices: the body mass index (BMI), fat mass, free fat mass, total abdominal fat volume (TAFV), total subcutaneous fat volume (TSFV), and total visceral fat volume (TVFV) of all the 52 patients were (31.8±1.8)kg/m2, (39.4±4.1)kg, (50.2±6.0)kg, (11 703±3 899)cm3, (7 418±2 969)cm3, and (4 314±1 692)cm3 before surgery, (28.5±1.4)kg/m2, (33.0±1.1)kg, (49.7±4.6)kg, (11 016±3 713)cm3, (7 044±2 970)cm3, (3 969±1 443)cm3 at 3 months after surgery, (27.1±1.7)kg/m2, (30.2±1.3)kg, (45.4±3.1)kg, (9 406±4 452)cm3, (6 442±3 307)cm3, and (2 964±1 694)cm3 at 6 months after surgery, (24.4±2.4)kg/m2, (32.6±1.1)kg, (48.6±2.7)kg, (7 612±3 029)cm3, (5 623±2 650)cm3, and (1 826±360)cm3 at 12 months after surgery, respectively, there were significant differences in the changes of these indices (F=130.2, 30.3, 4.9, 25.6, 11.9, 16.5, P<0.05). The BMI, fat mass, and TAFV at 3 months after surgery had significant differences compared with those before surgery (P<0.05), but free fat mass, TSFV, and TVFV had no significant difference (P>0.05). The BMI, fat mass, TAFV, and TVFV at 6 months after surgery had significant differences compared with those before surgery (P<0.05), but free fat mass and TSFV had no significant difference (P>0.05). The BMI, fat mass, TAFV, TSFV, and TVFV at 12 months after surgery had significant differences compared with those before surgery (P<0.05), but free fat mass had no significant difference (P>0.05). (3) Follow-up: all the 52 patients have completed the follow-up after surgery and the remission number of obesity was 35. No complications such as anastomotic hemorrhage, obstruction, or anastomotic leakage occured in all the 52 patients.@*Conclusion@#Laparoscopic Roux-en-Y gastric bypass can reduce abdominal visceral fat significantly, while quantitative computed tomography can help to evaluate the distribution of abdominal visceral fat accurately.
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Objective To evaluate the application value of quantitative computed tomography for evaluation of changes in abdominal fat after laparoscopic Roux-en-Y gastric bypass in obese patients.Methods The retrospective and descriptive study was conducted.The clinical data of 52 obese patients who underwent laparoscopic Roux-en-Y gastric bypass in the Third Medical Center of Chinese PLA General Hospital from March 2011 to February 2012 were collected.There were 24 males and 28 females,aged (43±9)years,with the range of 23-62 years.All the 52 patients underwent laparoscopic Roux-en-Y gastric bypass.Observation indicators:(1) surgical and postoperative conditions;(2) changes in anthropometric indices;(3) follow-up.Follow-up using outpatient examination was performed to detect complications of patients at 1,3,6,12 months after surgery up to February 2013.Measurement data with normal distribution were represented as Mean±SD,repeated measurement data were analyzed using repeated ANOVA.Count data were represented as absolute numbers.Results (1) Surgical and postoperative conditions:all the patients underwent laparoscopic Roux-en-Y gastric bypass successfully,without conversion to open surgery.The volume of intraoperative blood loss,operation time,and duration of hospital stay were (25± 11) mL,(78± 14) minutes,and (11±2) days.(2) Changes in anthropometric indices:the body mass index (BMI),fat mass,free fat mass,total abdominal fat volume (TAFV),total subcutaneous fat volume (TSFV),and total visceral fat volume (TVFV) of all the 52 patients were (31.8 ± 1.8)kg/m2,(39.4±4.1)kg,(50.2±6.0)kg,(l1 703±3 899)cm3,(7 418±2 969)cm3,and (4 314± 1 692)cm3 before surgery,(28.5±1.4)kg/m2,(33.0±1.1)kg,(49.7±4.6)kg,(11 016±3 713) cm3,(7 044± 2970)cm3,(3969±1 443)cm3 at 3 months after surgery,(27.1±1.7)kg/m2,(30.2±1.3)kg,(45.4± 3.1)kg,(9 406±4 452)cm3,(6 442±3 307)cm3,and (2 964±1 694) cm3 at 6 months after surgery,(24.4± 2.4)kg/m2,(32.6±1.1)kg,(48.6±2.7)kg,(7 612±3 029)cm3,(5 623±2 650)cm3,and (1 826±360) cm3 at 12 months after surgery,respectively,there were significant differences in the changes of these indices (F=130.2,30.3,4.9,25.6,11.9,16.5,P＜0.05).The BMI,fat mass,and TAFV at 3 months after surgery had significant differences compared with those before surgery (P＜0.05),but free fat mass,TSFV,and TVFV had no significant difference (P＞0.05).The BMI,fat mass,TAFV,and TVFV at 6 months after surgery had significant differences compared with those before surgery (P ＜ 0.05),but free fat mass and TSFV had no significant difference (P＞0.05).The BMI,fat mass,TAFV,TSFV,and TVFV at 12 months after surgery had significant differences compared with those before surgery (P＜0.05),but free fat mass had no significant difference (P＞ 0.05).(3) Follow-up:all the 52 patients have completed the follow-up after surgery and the remission number of obesity was 35.No complications such as anastomotic hemorrhage,obstruction,or anastomotic leakage occured in all the 52 patients.Conclusion Laparoscopic Roux-en-Y gastric bypass can reduce abdominal visceral fat significantly,while quantitative computed tomography can help to evaluate the distribution of abdominal visceral fat accurately.
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Objective The present study aimed to establish a bone mineral density (BMD) reference database in China and to investigate the prevalence of osteoporosis in Chinese adults aged 50 years and older using dual energy X-ray absorptiometry (DXA). Method A total of 75321 examineers over 25 years old who underwent health checkups in 7 health check centers between 2008 and 2018 were included. All centers used a GE Lunar-DXA system to measure BMD of the lumbar spine (L1-L4), femoral neck, and total femur. The same European Spine Phantom (ESP) was used for scanning 10 times at every center, a regression equation was generated, and BMD data were cross-calibrated in each center. Peak BMD and standard deviation (SD) were identified according to 5-year age groups, and T scores were calculated based on the peak BMD and SD. Osteoporosis was defined according to the World Health Organization criteria. The prevalence of osteoporosis was standardized based on 2010 national census data for the Chinese population. Result The mean BMD values decreased with age, were highest in North China, followed by Northeast China, East China, and Southwest China, respectively, and increased with body mass index. Males aged 20-30 years and females aged 35-40 years had peak BMD values. Peak BMD values of the lumbar spine, femoral neck, and total femur were 1.09 g/cm2, 0.97 g/cm2, and 0.97 g/cm2 in males, and 1.11 g/cm2, 0.84 g/cm2, and 0.88 g/cm2 in females, respectively. Among all scanned sites, the prevalence of osteoporosis was highest in the femoral neck in males (4.58％) and in the lumbar spine in females (23.38％). The age-standardized prevalence of osteoporosis at any site was 6.46％ in males and 29.13％ in females aged 50 years and older. Based on the 2010 national census data, 10879115 males and 49286542 females currently have osteoporosis. Conclusion Mean BMD values varied according to geographic region, body mass index, age group, and sex in Chinese adults. The age-standardized prevalence of osteoporosis was 6.46％ in males and 29.13％ in females aged 50 years and older.