双能X射线吸收法诊断青海地区女性绝经后类风湿性关节炎患者骨质疏松症及其危险因素分析

目的:探讨双能X射线吸收法(DXA)诊断青海地区女性绝经后类风湿性关节炎(RA)患者发生骨质疏松症(OP)的危险因素。方法:选取2022年5月至2023年4月青海省中医院收治的200例绝经后女性RA患者,所有患者入院后均进行骨密度(BMD)检测,采用DXA测量腰椎L1~L4、腰整体、大转子、Ward's三角区、整体、前臂整体等部位。根据BMD检测结果,将患者各部位BMD的T值≤-2.5 SD纳入OP组(121例),BMD的T值>-2.5 SD纳入非OP组(79例)。对比分析两组RA患者不同部位的BMD的T值;采用受试者工作特征(ROC)曲线下面积(AUC)分析BMD的T值诊断OP效能;采用logistic回归法分析青海地区绝经后RA患者发生OP的危险因素。结果:OP组L1、L2、L3、L4、腰整体、大转子、Ward's三角区、整体及前臂整体BMD的T值均明显低于非OP组。ROC曲线分析中,L1、L2、L3、L4、腰整体、大转子、Ward's三角区、整体及前臂整体BMD的T值诊断OP的灵敏度分别为96.20%、95.22%、90.16%、96.03%、92.01%、89.36%、99.26%、90.02%和96.03%,特异度分别为81.00%、82.19%、85.22%、83.06%、83.06%、90.22%、80.06%、86.23%和83.09%,AUC分别为0.908、0.905、0.896、0.906、0.903、0.879、0.918、0.901和0.906。logistic回归分析中,高龄、病程长、28个关节的风湿活动度评分(DAS28)、血沉及补充钙剂等均为青海地区绝经后女性RA患者发生OP的危险因素。结论:DXA检测RA发生OP患者BMD可作为OP评估的“金标准”,且影响青海地区绝经后女性RA患者发生OP的危险因素较多,临床应结合相关因素制定合理的措施,以降低OP的发生率。

放射性核素对双能X射线骨密度仪检测骨密度的影响研究

目的:研究核医学检查和治疗中常用放射性核素对双能X射线骨密度仪(DXA)检测骨密度(BMD)的影响。方法:对DXA设备专用质量保证(QA)模块和脊椎模体均进行常规扫描,在QA模块旁及脊椎模体的水槽中分别加入常用放射性核素锝99m(^(99)Tc^(m))-亚甲基二膦酸盐(^(99)Tc^(m)-MDP)、氟18(^(18)F)-氟代脱氧葡萄糖(^(18)F-FDG)和碘[^(131)I]化钠(Na^(131)I)后扫描,对检测所得高、中、低BMD值、身体成分百分含量值、第1、2、3、4节腰椎(L_(1)、L_(2)、L_(3)、L_(4))及4节腰椎平均(L_(1)~L_(4))BMD值、T值进行对比分析。结果:在QA模块旁分别放置^(99)Tc^(m)-MDP、^(18)F-FDG、Na^(131)I后的扫描与QA模块的常规扫描所得高、中、低BMD值及身体成分百分含量值相比,差异均无统计学意义(F_(BMD值)=1.621、0.259、0.099,F_(身体成分百分含量值)=0.367、0.151、0.635;P>0.05);向脊椎模体的水槽中分别注入放射性核素^(99)Tc^(m)-MDP、^(18)F-FDG、Na^(131)I后的扫描和脊椎模体的常规扫描所得L_(1)、L_(2)、L_(3)、L_(4)及L_(1)~L_(4)的BMD值及T值相比,差异均无统计学意义(F_(BMD值)=0.435、0.529、0.507、0.489、0.516,F_(T值)=0.634、1.585、0.961、0.777、0.801;P>0.05)。结论:核医学检查和治疗中常用放射性核素^(99)Tc^(m)-MDP、^(18)F-FDG、Na^(131)I对DXA检测BMD无影响。

用DXA测量大鼠骨密度和身体成分的精密度

目的:采用双能X线吸收法(DXA)进行大鼠骨密度(BMD)和身体软组织成分测量的精密度试验,探讨DXA对大鼠骨密度和身体软组织成分测量结果的可靠性。方法:对30只SD大鼠进行了DXA二次重复扫描,采用小动物专用软件分别分析大鼠上肢、下肢、躯干、全身等部位的骨密度,以及脂肪(fat)组织、肌肉(lean)组织和fat百分比,计算其精密度(以变异系数的均方根RMS-CV表示)。结果:SD大鼠全身骨密度测量精密度(RMS-CV)为0.9%,最小显著变化值为0.003 g/cm2;大鼠全身软组织成分:脂肪、肌肉组织的含量和fat组织所占软组织的百分比的精密度分别为9.6%、1.3%和9.7%。结论:DXA能较准确测量大鼠全身骨密度和软组织成分。

两种DXA骨密度体模比较研究

研究比较国产QC-2型腰椎骨密度体模（以下称QC-2体模）和欧洲脊椎骨密度体模（以下称ESP体模）在双能X射线全身骨密度仪（以下称DXA）检定中的差异性。用DXA仪器对这两种体模分别进行检测,对测量结果进行比较分析。（1）QC-2型体模和ESP型体分别被仪器进行测量时,仪器测量的BMD同两个体模的BMD相比,误差分别在-15.1%-11.5%和-16.1%-12.5%之间;而且,两个体模的各自标称值与相应的仪器测量值之间,分别都有非常好的线性关系,r〉0.99。（2）用回归方程进行校正后,仪器值（BMD）与两个体模的各自的标称值之间的误差分别在-3.8%-4.4%和在-3.8%-4.4%之间。用成对样本均数比较方法,对校正结果进行统计分析,经配对t检验,二者结果没有显著差异（P〉0.05）。表明这两种腰椎骨密度体模都能用于双能X射线全身骨密度仪（DXA）的检定。

外源性脂肪对DXA测量骨密度结果的影响

目的:观察外源性脂肪对DXA(Hologic QDR4500A型)测量腰椎模型骨密度(bone mineral density,BMD)结果的影响。方法:准备不同厚度的猪脂肪(猪油和炼油各2块,5cm和10cm厚),放置在腰椎模型上,测量放置前后的BMD。结果:放置不同厚度猪油后只有L1的BMD下降有统计学意义(P<0.05);放置5cm厚炼油时BMD,骨量(BMC),骨面积(BA)大都显著下降,放置10cm厚炼油时3项指标的下降都有统计学意义(P<0.05或P<0.01)。结论:外源性脂肪可以使Hologic QDR4500A型DXA测量腰椎模型BMD测量结果显著下降,这种影响可能会造成肥胖者BMD结果失真进而影响骨质疏松诊断的正确性。

我院临床医师对于DXA检查项目认知调查和对策分析

目的:本研究期望通过调查,明确我院临床医师对DXA检查项目的认知现状,为后续改进制订详细对策,提升临床医师OP诊查水平。方法:采用现场问卷法,调查2017年10月-2018年10月期间中国医科大学附属盛京医院临床科室中开立DXA检查年数量前十位科室的医师。问卷信息包括临床医师基本信息以及对于DXA认知情况(包括检查人群、开立项目、开立部位、结果解读、结果利用、结果互认、随诊周期和复诊结果解读等方面)。结果:共计调查38例次。调查发现,临床医师在检查人群、开立项目两方面能够做到100%掌握,但其他项目掌握仍存在较大问题。合理率由高到低排序分别为结果解读(81.6%),结果利用(76.3%),复诊结果解读(68.4%),结果互认(47.4%)和随诊周期(34.2%)。统计分析结果发现,职称级别是DXA认知度差异的独立风险因素(OR=10.50),即中级职称医师在DXA认知评价方面明显低于副高级以上职称的医师。另外,并未发现不同科室、患者疾病差异、医师年龄、工作年限等其他导致DXA认知度差异的独立风险因素。结论:针对调查发现的诸多问题,后续需有针对性制订对策,努力提高临床医师OP筛查和诊治能力,督促其持续改进。

Validation of quantitative computed tomography-derived areal bone mineral density with dual energy X-ray absorptiometry in an elderly Chinese population

Background The performance of computed tomography X-ray absorptiometry （CTXA） against the dual energy X-ray absorptiometry （DXA） as standard has not been studied in Chinese population. The aim of this study was to evaluate the precision of this measurement and validate the value of quantitative computed tomography （QCT） by comparing CTXA results with DXA results in an elderly Chinese population. Methods One hundred and three females of 46 to 76 years old and 49 males of 52 to 76 years old were recruited from the Prospective Urban Rural Epidemiology study. All subjects underwent hip scans by both QCT and DXA on the same day. For precision determination, 30 subjects had duplicate DXA hip scans. The hip QCT data of a subset of 27 subjects were separately analyzed by two observers and reanalyzed by one observer at a different time. The inter- and intra-observer variations of CTXA measurement were assessed, and the difference and correlation between CTXA and DXA results were analyzed. Results The inter- and intra-observer variations of CTXA were 0.070 and 0.024 g/cm^2 in the femoral neck （FN）, and 0.030 and 0.012 g/cm2 in the total hip （TH）, which were comparable to the DXA inter-scan variations （0.013 g/cm2 for FN and 0.014 g/cm2 for TH）. The results of CTXA bone mineral density （BMD） were highly correlated with those of DXA （R2 = 0.810 for FN and R2 = 0.878 for TH）. The BMD values of CTXA in FN and TH were lower than those of DXA by 21.0% and 17.8% （P〈0.05）, respectively. However, after appropriate transformation, the difference was eliminated and a comparable T score could be obtained. Conclusions CTXA shows good agreement with DXA for the measurement of BMD in the proximal femur, which makes QCT suitable for the quantification of bone mineral content in the hip and helpful for the diagnosis of osteoporosis.

双能X线吸收法测量身体成份精确度的研究

目的确定使用双能X线吸收法(DXA)在测定全身和局部身体成份短期精确度,以指导临床监测方案。方法对10名成年女性志愿者使用DXA(GE LUNAR PRODIGY型)骨密度仪进行了全身体成份测定。每名志愿者测量10次,每天重复5次分在2d(间隔不超过4d)中进行。志愿者测量期间饮食、运动等无明显改变,无腹泻等影响体重的疾病。每次测试需穿同样衣服,每次测量结束均离开骨密度仪,站到地面,下次测量再重新摆放体位。由同一名技师进行操作并分析。计算短期精确度。结果全身、上肢、大腿、躯干、男性区域及女性区域骨矿含量测定的变异系数(CV)分别为1.1%、1.5%、0.9%、2.8%、3.4%和1.7%,脂肪测定的CV分别为1.2%、3.5%、2.3%、2.7%、3.4%和1.8%,组织测定的CV分别为0.7%、1.4%、1.8%、1.6%、2.2%和1.4%,脂肪百分比的CV分别为1.2%、2.4%、1.1%、2.1%、2.3%和1.5%。结论全身体成份测定的CV在0.7%～1.2%,局部体成份测定的CV大部分在1%～2.5%之间。局部测定的精确度不如全身测定的精确度。全身测定和局部测定的精确度均可以满足临床和科研需要。

放射吸收法测量手指骨密度对于骨质疏松的诊断价值

目的评价放射吸收法（radiographic absorptiometry,RA）测量指骨骨密度（bone mineral density,BMD）的准确性和对骨质疏松的诊断价值。方法选取志愿者80例（男性30例,女性50例）,分别用RA和双能X线骨密度仪（dual energy X-ray absorptiometry,DXA）测量非优势手的2、3、4指中节指骨BMD值和T值（n=80）,用DXA测量正位腰椎（n=77）、左侧近段股骨（股骨颈、股骨粗隆及全股骨）（n=78）的BMD值和T值。分别以DXA测量正位腰椎T值、左侧近段股骨T值、RA测量指骨T值进行骨质疏松诊断（T值≥-1.0SD为骨量正常,-2.5SD〈T值〈-1.0SD为低骨量,T值≤-2.5SD为骨质疏松）。用SPSS11.5软件对RA和DXA测量的指骨BMD值进行相关性分析,对3组骨质疏松诊断结果分别进行一致性分析。结果RA测量与DXA测量指骨BMD值的相关系数=0.864（P〈0.01）,指骨与腰椎总体诊断符合率为58.4%,指骨与近段股骨总体诊断符合率为56.4%,腰椎与近段股骨总体诊断符合率为68.8%。结论RA测量的指骨BMD值与DXA测量值密切相关,但目前直接使用WHO对DXA测量推荐部位（腰椎、髋部或前臂）BMD制定的诊断标准对RA测量指骨BMD进行骨质疏松的诊断并不合适。

骨质疏松老年妇女股骨近端16层螺旋CT的定量研究

目的:通过16层螺旋CT中vQCT技术对骨质疏松性椎体骨折及无骨折老年妇女股骨近端进行多个容积性BMD指标的测量,比较两组妇女股骨近端小梁骨、皮质骨和整体骨容积性BMD的差异,评价骨质疏松性椎体骨折对股骨近端骨密度的影响程度.方法:将26例骨质疏松性椎体骨折病人归为第一组,年龄与第一组匹配的无脊椎骨折的30例骨质疏松老年妇女归为第二组.应用GE公司LightSpeed 16型螺旋CT对56例病人股骨近端行容积扫描,行薄层重建图像,层厚1.25mm,在3D-VR影像中沿左股骨颈长轴方向确定数个与之相垂直的平面作为固定的解剖学标记,选取左侧股骨近端整体骨、股骨颈及粗隆间测量兴趣体积(VOI),经Sun ADW4.0计算机工作站直方图(histogram)功能测量左侧股骨颈3D小梁骨BMD(N-TRAB)、3D整体骨BMD(N-INTGL),左侧粗隆间3D小梁骨BMD(T-TRAB)、3D整体骨BMD(T-INTGL),左侧股骨近端 3D小梁骨BMD(FEM-TRAB)、3D皮质骨BMD(FEM-CORT)和3D整体骨BMD(FEM-INTGL)值.所有病人双能X线吸收仪(GE-Lunar公司DPX型)测量指标为左侧股骨颈(NECK)及粗隆间BMD(TROCH).比较两组老年妇女间9项BMD指标差异采用协方差分析.结果:两组老年妇女间股骨近端容积性BMD数值除FEM-CORT一项指标外其差异存在统计学意义,在调节年龄和体型因素后仍然在差异,第一组老年妇女比第二组容积性BMD值下降程度为14%～18%,且vQCT技术中股骨近端容积性BMD的测量精度较高;两组间DXA指标中BMD值的差异在调节年龄和体型因素后无统计学意义:在TTRAB指标中第一组老年妇女比第二组的BMD值下降幅度达17.7%,高于N-TRAB中BMD值的下降度14.3%.结论:首次应用16层螺旋CT进行股骨近端vQCT测量,证实此项技术比DXA更全面地反应骨质疏松性椎体骨折比无骨折老年妇女股骨近端骨密度的下降状况,且不受体型大小和骨形态变化因素的影响.

双能X线骨密度仪评估人体脂肪含量对骨密度的影响研究

目的:采用双能X线骨密度仪评估人体脂肪组织含量对骨密度的影响。方法:选取进行骨密度检查的120名健康人,均采用双能X线骨密度仪(DXA)测量全身骨密度(BMD)、股骨颈骨密度、全髋及腰椎骨密度值和脂肪组织含量。将120名受检者根据性别、脂肪质量高低情况平均分为高/低脂肪含量组,比较组间DXA检测骨密度值的差异,并分析脂肪含量和DXA骨密度的内在相关性。结果:男性脂肪含量显著低于女性[(15. 6±3. 5) kg vs.(19. 3±4. 2) kg],差异具有统计学意义(P <0. 05);男性高/低脂肪含量组间BMD、股骨颈、全髋及腰椎骨密度比较,差异无统计学意义(P> 0. 05),女性高脂肪含量组的上述测量数据均高于低脂肪含量组,差异具有统计学意义(P <0. 05); Pearson法分析提示男性DXA骨密度测量值和脂肪含量无相关性(P> 0. 05),而在女性中呈正相关(P <0. 05)。结论:人体脂肪含量对骨密度的影响具有性别特征,女性脂肪含量对骨密度有一定正面影响。

Cerebral artery evaluation of dual energy CT angiography with dual source CT

Background Conventional computed tomography angiography （CTA） is time consuming, user-dependent and has poor image quality in skull base region. This study assessed the feasibility of a new method, dual energy CTA for depicting the cerebral artery.Methods Phantom scan was done with head CTA sequences on dual source CT and 64 spiral CT for radiation dose calculation. Dual energy CTA was done with dual source CT on 36 patients who were suspected of having cerebral vascular disease. Three series axial images in 0.75 mm thick, 0.4 mm increment were acquired, which were named with 80 kV, 140 kV and merged images; 80 kV and 140 kV images were transferred into dual energy software, and maximum intensity projection （MIP） image was generated quickly by dual energy bone remove （DEBR group）; merged images were transferred into In Space software to acquire MIP image through manual conventional bone remove （CoBR group）. Post processing time and reading time were compared. Image qualities of the two groups were compared, mainly focusing on skull base segments of internal carotid artery and bone subtraction. ANOVA and SNK tests were applied for radiation dose comparison. Student＇s t test and Wilcoxon rank sum test were applied for assessing differences between data for significance. Cohen＇s kappa was used for interobserver agreement. Results Radiation dose of phantom scan showed dual energy CTA was between digital bone subtraction and conventional CTA. The post processing time and reading time were much shorter in DEBR than CoBR, and image quality in skull base was much higher in DEBR than CoBR （P〈0.01）. There was no significant difference for suprasellar vessels between two groups （P〉0.5）. Interobserver agreement for all vessel segments was excellent （kappa=0.97）. Conclusions Dual energy CTA is a reliable, new modality for depicting cerebral artery, overcoming the limitation of conventional CTA in the skull base region. It can save much time in post processing and reading than conventional CTA.

Managing osteoporosis in ulcerative colitis: Something new?

The authors revise the latest evidence in the literature regarding managing of osteoporosis in ulcerative colitis (UC), paying particular attention to the latest tendency of the research concerning the management of bone damage in the patient affected by UC. It is wise to assess vitamin D status in ulcerative colitis patients to recognize who is predisposed to low levels of vitamin D, whose deficiency has to be treated with oral or parenteral vitamin D supplementation. An adequate dietary calcium intake or supplementation and physical activity, if possible, should be guaranteed. Osteoporotic risk factors, such as smoking and excessive alcohol intake, must be avoided. Steroid has to be prescribed at the lowest possible dosage and for the shortest possible time. Moreover, conditions favoring falling have to been minimized, like carpets, low illumination, sedatives assumption, vitamin D deficiency. It is advisable to assess the fracture risk in all UC patient by the fracture assessment risk tool (FRAX® tool), that calculates the ten years risk of fracture for the population aged from 40 to 90 years in many countries of the world. A high risk value could indicate the necessity of treatment, whereas a low risk value suggests a follow-up only. An intermediate risk supports the decision to prescribe bone mineral density (BMD) assessment and a subsequent patient revaluation for treatment. Dual energy X-ray absorptiometry bone densitometry can be used not only for BMD measurement, but also to collect data about bone quality by the means of trabecular bone score and hip structural analysis assessment. These two indices could represent a method of interesting perspectives in evaluating bone status in patients affected by diseases like UC, which may present an impairment of bone quality as well as of bone quantity. In literature there is no strong evidence for instituting pharmacological therapy of bone impairment in UC patients for clinical indications other than those that are also applied to the patients with osteoporosis. Therefore, a reasonable advice is to consider pharmacological treatment for osteoporosis in those UC patients who already present fragility fractures, which bring a high risk of subsequent fractures. Therapy has also to be considered in patients with a high risk of fracture even if it did not yet happen, and particularly when they had long periods of corticosteroid therapy or cumulative high dosages. In patients without fragility fractures or steroid treatment, a medical decision about treatment could be guided by the FRAX tool to determine the intervention threshold. Among drugs for osteoporosis treatment, the bisphosphonates are the most studied ones, with the best and longest evidence of efficacy and safety. Despite this, several questions are still open, such as the duration of treatment, the necessity to discontinue it, the indication of therapy in young patients, particularly in those without previous fractures. Further, it has to be mentioned that a long-term bisphosphonates use in primary osteoporosis has been associated with an increased incidence of dramatic side-effects, even if uncommon, like osteonecrosis of the jaw and atypical sub-trochanteric and diaphyseal femoral fractures. UC is a long-lasting disease and the majority of patients is relatively young. In this scenario primary prevention of fragility fracture is the best cost-effective strategy. Vitamin D supplementation, adequate calcium intake, suitable physical activity (when possible), removing of risk factors for osteoporosis like smoking, and avoiding falling are the best medical acts.

Adipokines and C-reactive protein in relation to bone mineralization in pediatric nonalcoholic fatty liver disease

AIM: To investigate bone mineral density (BMD) in obese children with and without nonalcoholic fatty liver disease (NAFLD); and the association between BMD and serum adipokines, and high-sensitivity C-reactive protein (HSCRP). METHODS: A case-control study was performed. Cases were 44 obese children with NAFLD. The diagnosis of NAFLD was based on magnetic resonance imaging (MRI) with high hepatic fat fraction (≥ 5%). Other causes of chronic liver disease were ruled out. Controls were selected from obese children with normal levels of aminotransferases, and without MRI evidence of fatty liver as well as of other causes of chronic liver diseases. Controls were matched (1-to 1-basis) with thecases on age, gender, pubertal stage and as closely as possible on body mass index-SD score. All participants underwent clinical examination, laboratory tests, and whole body (WB) and lumbar spine (LS) BMD by dual energy X-ray absorptiometry. BMDZ-scores were calcu- lated using race and gender specific LMS curves. RESULTS: Obese children with NAFLD had a significantly lower LS BMDZ-score than those without NAFLD [mean, 0.55 (95%CI: 0.23-0.86) vs 1.29 (95%CI: 0.95-1.63); P < 0.01]. WB BMD Z-score was also decreased in obese children with NAFLD compared to obese children with no NAFLD, though borderline significance was observed [1.55 (95%CI: 1.23-1.87) vs 1.95 (95%CI: 1.67-2.10); P = 0.06]. Children with NAFLD had significantly higher HSCRP, lower adiponectin, but similar leptin levels. Thirty five of the 44 children with MRI-diagnosed NAFLD underwent liver biopsy. Among the children with biopsy-proven NAFLD, 20 (57%) had nonalcoholic steatohepatitis (NASH), while 15 (43%) no NASH. Compared to children without NASH, those with NASH had a significantly lower LS BMD Z-score [mean, 0.27 (95%CI: -0.17-0.71) vs 0.75 (95%CI: 0.13-1.39); P < 0.05] as well as a significantly lower WB BMD Z-score [1.38 (95%CI: 0.89-1.17) vs 1.93 (95%CI: 1.32-2.36); P < 0.05]. In multiple regression analysis, NASH (standardized β coefficient, -0.272; P < 0.01) and HSCRP (standardized β coefficient, -0.192; P < 0.05) were significantly and independently associated with LS BMD Z-score. Similar results were obtained when NAFLD (instead of NASH) was included in the model. WB BMD Z-scores were significantly and independently associated with NASH (standardized β coefficient, -0.248;P < 0.05) and fat mass (standardized β coefficient, -0.224;P < 0.05). CONCLUSION: This study reveals that NAFLD is associated with low BMD in obese children, and that systemic, low-grade inflammation may accelerate loss of bone mass in patients with NAFLD.

Green coffee bean extract improves obesity by decreasing body fat in high-fat diet-induced obese mice

Objective:To evaluate possible lipid catabolism and body fat regulation effects of 3-caffeoylquinic acid in Green coffee bean extract(GCBE) in high-fat diet(HFD)-induced obese mice.Methods:Obesity was induced in mice using a HFD for four weeks.Then,mice were fed only HFD or HFD with GCBE at 50,100,and 200 mg/kg.Fatty acid synthesis mechanism regulation of body fat was investigated through real-time PCR and Western blot assay.Body fat reduction was measured through dual-energy X-ray absorptiometry.Results:In HFD-induced obese mice,GCBE treatment significantly decreased body weight gain,liver weight and white adipose tissue weights with regulation of adipose tissue lipolysis hormones,like adiponectin and leptin.GCBE treatment decreased mR NA expression levels of adipogenesis and adipocyte metabolism related genes in adipose tissues and the liver,and decreased the corresponding protein expression.Dual energy X-ray absorptiometry measurements were used to compare body fat between mice on high-fat and those treated with GCBE.GCBE treated mice had a lower fat mass compared to HFD alone fed mice and relative body weight and fat mass were markedly decreased.Conclusions:GCBE has a potential anti-obesity effect with lowering body fat accumulation by regulating adipogenesis and lipid metabolism-related genes and proteins in WAT and liver.

Relationship between peak oxygen uptake and regional body composition in Japanese subjects

Purpose： To investigate the link between peak oxygen uptake and regional body composition by dual energy X-ray absorptiometry （DEXA） in Japanese subjects. Methods： A total of 93 men （42.2 ± 12.3 years old） and 106 women （43.5 ± 12.3 years old） were enrolled in this cross-sectional investigation study. Peak oxygen uptake was measured by the breath-by-breath method. Regional body composition i.e., body fat mass, lean body mass, and body fat percentage was evaluated using DEXA. In addition, metabolic risk parameters were also evaluated. Results： Peak oxygen uptake was 37.6± 8.7 mL/kg/min in men and 31.1 ± 6.4 mL/kg/min in women, and decreased with age in both genders. Peak oxygen uptake was significantly correlated with total body fat percentage （men： r = -0.684, p 〈 0.0001; women： r = -0.681, p 〈 0.0001）. These associations remained even after adjusting for age and total lean body mass. However, peak work rate was positively and significantly correlated with leg lean body mass. Conclusion： Peak oxygen uptake was closely correlated with total body fat percentage in both genders. Aerobic exercise as well as leg resistance training might be useful for improving peak oxygen uptake in Japanese subjects. Copyright

Body composition of healthy Spanish children

This paper shows the distribution of the body compartments, and the age and gender related changes in Spanish children. Subjects and Methods: A total of 231 healthy children from Madrid (Spain) were recruited and divided into 3 groups according to age (birth-5, 6-10, 11-15y). Body compartments (fat mass, lean mass and bone mass) measures were obtained from dual energy X-ray absorptiometry (DXA) scans. Total and regional body compositions were evaluated. Results: There were gender differences for TBFM (total body fat mass) in 11 - 15 year age group and for TLBM (total lean body mass) in all age groups except for the 6 - 10 year age group. TBMC (total bone mineral content) shows significant gender differences form birth. Conclusions: Contrary to boys, girls showed from early infancy a smaller proportion of muscle mass and a higher proportion of body fat (from the age of 10), with fat deposits being mostly peripheral. Bone mass and muscle mass values were higher in boys.

ROI缺失对髋部骨密度测量结果的影响

目的研究使用双能X射线吸收法(DXA)测定髋部骨密度时,股骨头和股骨颈交界区外、上部感兴趣区(ROI)缺失对全髋骨密度值及T值的影响,为扫描后处理提供数据支持。方法在2018年5月28日-2021年8月17日的符合检测技术标准并存在髋部ROI缺失的受检者中,根据标画前的T值,选取正常组、骨量减少组和骨质疏松组各50例。通过对缺失ROI进行人工标画,对比标化前后骨密度值、T值的变化,分析造成问题的原因及问题造成的影响,并提出改进方案。同时对2021年5月1日-5月31日接受DXA检测的所有门诊女性患者568例进行了髋部ROI缺失发生率的调查。结果髋部ROI缺失,会造成91.3%受检者的全髋骨密度增加,平均上涨5.0×10^(-3)g/cm^(2);6%受检者骨密度无变化;2.7%受检者骨密度降低,平均降低1.0×10^(-3)g/cm^(2)。30%受检者共45人全髋T值增加,其中44人T值增加0.1,1人T值增加0.2,其余70%受检者T值无变化。结论使用DXA进行髋部骨密度扫描时,ROI缺失会导致全髋骨密度增加,甚至造成T值的改变。为了给临床提供更可靠的诊断依据,应对缺失的骨缘进行人工标画。

双能X射线骨吸收测量仪的辐射剂量评价

目的 评价双能X射线骨吸收测量仪（DXA）的辐射剂量。方法 使用美国Radcal公司多功能剂量仪（1 800 cc电离室）对美国Norland公司XR-800 DXA （笔形束扫描，100/46.8 kVp、1.3 mA）进行剂量检测，得到正位腰椎、髋关节、腕骨、下颌骨扫描的受检者入射体表剂量（ESD）；使用Radcal剂量仪对美国Hologic公司Discovery A DXA （扇形束扫描，140/100 kVp、2.5 mA）进行剂量检测，得到正位腰椎、髋关节扫描的受检者ESD；对比两种机器在不同扫描方式下骨密度检查受检者的ESD。使用美国Fluke公司451P巡测仪对这两台DXA仪器正位腰椎扫描分别在距床面模体中心1 m和地面高1 m处测量周围剂量当量率水平。结果 Radcal公司多功能剂量仪测得Norland XR-800 DXA受检者正位腰椎扫描的ESD为0.43 μGy （高速度）和0.73 μGy （标准速度），髋关节、腕关节、下颌骨扫描的ESD分别为1.93（初扫＋测量扫描）、0.40和1.06 μGy （初扫＋测量扫描）。Radcal多功能剂量仪测得Hologic Discovery A DXA受检者正位腰椎、髋关节扫描的ESD分别为65.6和63.9 μGy。Norland XR-800 DXA 4个检查部位在不同扫描方式和不同扫描速度下，受检者ESD均〈2 μGy，Hologic Discovery A DXA正位腰椎及髋关节受检者ESD均〈66 μGy，与两台机器的操作手册给出的数据基本一致。使用451P巡测仪对两台DXA周围剂量当量率测量显示，扇形束机器高于笔形束机器65倍。结论 受检者做骨密度检查的ESD是医用X射线检查项目中较低的，笔形束扫描DXA常规腰椎及髋关节的受检者ESD约为扇形束扫描DXA检查剂量的1/153~1/33。笔形束DXA扫描的工作人员接受的剂量可忽略不计，扇形束DXA扫描的工作人员接受的剂量〈20 mSv/年的个人剂量限值。