【作者】 弓健；

【导师】 徐浩；

【作者基本信息】 暨南大学 ， 影像医学与核医学， 2013， 博士

【摘要】 目的通过双能x线吸收法(DXA)重复测量的短期精密度试验来获取股骨颈骨强度(HSA)参数与身体成分参数的精密度,并计算相应误差的最小显著变化(LSC)。方法73名健康成年志愿者进行了双侧股骨近端的DXA HSA精密度试验,分别计算单、双侧股骨近端骨密度(BMD)和HSA测量参数[截面面积(CSA)、截面转动惯量(CSMI)、截面模量(Z)、皮质骨外径(PD)、皮质骨内径(ED)和皮质骨厚度(CT)]的精密度[以变异系数均方根(RM-CV%表示)]；50名健康成年志愿者进行了DXA全身扫描精密度试验,计算全身身体成分DXA测量参数[脂肪含量(FM)、瘦组织含量(LM)和骨矿物质含量(BMC)]的精密度(以RM-CV%表示)。并进一步计算出在95%的可信区间内所有测量参数误差值的最小范围(以LSC表示)。结果DXA单侧股骨颈测量中,HSA各参数RM-CV%在0.8～4.0%之间；双侧股骨颈测量中,HSA各参数的平均值RM-CV%在0.6～2.8%之间。双侧股骨颈测量HSA参数精密度较单侧测量提高了13～33%。身体成分测量精密度各参数RMS-CV%均在2%以下。结论采用DXA测量股骨颈HSA各参数和全身身体成分各参数的精密度较高,可以满足临床研究的需要。目的在进行了双能X线吸收法(DXA)左、右侧股骨颈骨强度(HSA)测量参数差异比较的基础上,应用HSA中的的骨强度参数和骨结构参数分析股骨颈生物力学在不同性别、不同年龄阶段以及不同骨折风险人群中的表现情况,探寻不同人群HSA参数随年龄增长而变化的结构和力学生物学基础。方法400名不同人群受试者的左、右侧股骨HSA测量参数分别采用配对t检验和Pearson相关分析比较两者之间的差异和相关性。分析了3855例男、女性人群代表股骨颈骨强度的HSA参数[截面面积(CSA)、截面转动惯量(CSMI)和截面模量(Z)]与年龄的相关性,比较人群不同阶段之间(中青年男性和老年男性；绝经前女性和绝经后女性)HSA参数[CSA、CSMI、Z、皮质骨外径(PD)、皮质骨内径(ED)和皮质骨厚度(CT)]的差异。对正常组、骨量减少组和骨质疏松组人群的HSA测量参数进行多样本比较的秩和检验,并应用两样本比较的秩和检验进一步分析了绝经后女性和老年男性人群HSA参数随年龄变化的趋势。结果双侧股骨颈HSA各参数之间均没有发现显著差异(p>0.05),且呈高度正相关(r=0.801～0.921,p<0.05)。老年男性和绝经后女性的CSA、CSMI和Z随年龄增长而显著下降(r=-0.183～-0.495,p<0.05),而中青年男性和绝经后女性未发现与年龄增长的负相关关系。绝经后女性股骨颈骨CSA、CSMI和Z、CT低于绝经前女性,PD和ED未发现两组差异；老年男性股骨颈CSA、CSMI和Z和CT低于的中、青年男性,但PD和ED高于后者(p<0.05)。老年男性和绝经后女性的CSA、CSMI和Z均随着骨折风险增加而降低,而且均随着年龄增长而降低,但是与股骨颈骨密度的下降趋势并不一致(p<0.05)。结论左、右侧股骨颈之间的骨强度没有显著差异。在股骨颈骨量随着年龄的增加而减少的情况下,其强度也逐渐降低,但股骨颈通过骨的重建改变其截面的结构,存在对负荷减少以及对骨强度的维持的适应现象。目的本研究应用双能x线吸收法(DXA)分别在不同BMI阶段的成年男、女人群中分析股骨颈骨强度(HSA)与不同身体成分之间的关系。方法按世界卫生组织(WHO)体重指数标准将受试者分组,低体重组(BMI≤18.5)女性329人,男性109人；正常体重组(18.5<BMI<25)女性1850人,男性718人；超重组(25≤BMI<30)女性482人,男性282人；肥胖组(BMI≥30)女性52人,男性33人。分别测量每组人群的骨密度(BMD)、全身瘦组织(LM)含量、脂肪组织(FM)含量、以及HSA参数[截面面积(CSA)、截面转动惯量(CSMI)和截面模量(Z)],每组间进行了HSA参数与身体成分参数的相关性分析和非配对t检验,并应用协方差分析对HSA参数进行了体重、FM和LM校正后的组间比较。结果低体重组的CSMI、CSA和Z较正常体重组低,而超重和肥胖组CSMI、 CSA和Z高于正常体重组(p<0.05)。在各组中LM均都与CSMI、CSA和Z呈高度正相关(r=0.310～0.616,p<0.05)。当经过LM校正后,男、女性低体重、超重、肥胖组的CSA、CSMI和Z与正常体重组无显著差异；当经过FM校正后,男、女性低体重、超重、肥胖组的CSMI、CSA和Z与正常体重组的统计学差异仍显著存在(p<0.05)；当经过体重校正后,男性低体重、超重、肥胖组的CSA、 CSMI和Z与正常体重组无显著差异,女性低体重、超重、肥胖组的CSMI、CSA和Z与正常体重组的统计学差异仍显著存在(p<0.05)。多元回归分析显示：成年男、女性各组中中LM都是显著变量,且LM的标准偏回归系数均高于FM。结论在成人男、女性人群中LM都是一个影响骨强度的决定因素,骨强度的高低主要是对LM所代表的动态负荷适应的结果。更多还原

【Abstract】 Objective To estimate dual energy X-ray absorptiometry(DXA) short-term variability of hip strength analysis (HSA) in femoral necks and body composition parameters and establish the least significant change (LSC) to monitor these parameters from repeat subject scans.Methods73health volunteers had two repeated DXA measurements of bilateral proximal femur and50health volunteers had two repeated DXA measurements of whole body. Short-term variability of HSA parameters and whole body composition parameters were expressed as the root-mean-square coefficient (RMS-CV%) of variation and LSC at95%confidence level.Results At the single hip, the HSA parameters RMS-CV%were observed in0.8～4.0%of cases. At the dual hips, the HSA parameters RMS-CV%were0.6～2.8%。 The HSA parameters reproducibility improved13～33%by measuring the dual femur.Conclusions DXA measurements have low precision errors level in HSA and whole body composition scanning. Objective After exanimate the difference in hip strength analysis (HSA) parameters which included bone cross-sectional area (CSA), cross-sectional moment of inertia (CSMI), section modulus (Z), Periosteal Diameter (PD), Endocortical Diameter(ED) and Cortical Thickness (CT) at bilateral femoral neck dual energy X-ray absorptiometry (DXA) measurements, the study try to investigate the bone strength and cross section structure changes with age between men and women femoral neck by DXA scanning, and try to explain these findings by Mechanobiology theory.Methods400subjects were selected to compare the HSA parameters in dual femora necks. The data from3855normal subjects were analyzed to investigate HSA parameters in different sex group and age group. The study also investigated the difference of HSA parameters in normal, osteopenia and osteoporosis group. Age trends of HSA parameters (CSA, CSMI and Z) were evaluated in old men and postmenopausal women.Results There were high positive correlations between the left and right femoral neck HSA parameters (r=0.801～0.921, p<0.05), and there was no difference between bilateral femoral neck parameters (p>0.05). The decline of bone strength (CSA, CSMI and Z) with aging occurs in old men and postmenopausal women (r=-0.183～-0.495,p<0.05). Comparing with premenopausal women, postemenopausal women have lower bone strength and cortical thickness. Comparing with young men, old men have lower bone strength and cortical thickness, but have high periosteal diameter and endocortical diameter (p<0.05). Hip strength parameters were declined with osteoporotic fracture risk increasing (p<0.05). There were some differences between BMD and HSA parameters (CSA, CSMI and Z) in relative age trends at femoral neck (p<0.05)Conclusions There was no difference between left and right femoral neck bone strength. Aging loss of bone mass in the femoral neck does not necessarily mean reduced bone strength directly. HSA parameters in old men and postmenopausal women showed that reduction in bone strength was not dependent on decline in BMD. Objective The aim of this dual energy X-ray absorptiometry (DXA) study was to compare hip strength analysis (HSA) at femoral neck in low weight, overweight or obesity adults with gender matched normal weight controls. The relationship of body weight, lean mass (LM) and fat mass (FM) was investigated to indices of femoral neck strength.Methods3855adults were separated by body mass index (BMI) into low weight, normal weight, overweight and obesity groups. DXA measurements of the proximal femur and total body were made in these adults groups using a DXA bone densitometer. Bone mineral density (BMD), LM, FM, and HSA parameters which included bone cross-sectional area (CSA), cross-sectional moment of inertia (CSMI) and the section modulus (Z) were measured. Data were analyzed by Student’s t-test, Pearson correlation coefficients examination, and one-way analysis of covariance (ANCOVA).Results Overweight and obesity adults had higher body weight, LM, FM, BMI, CSA, CSMI and Z than normal weight controls, but low weight adults had lower body weight, LM, FM, BMI and HSA parameters than normal weight controls (p<0.05) LM correlated well with CSA, CSMI and Z in all BMI groups (r=0.310～0.616, p<0.05). After adjustment for LM, there were no significant differences between normal weight group with low weight, overweight or obesity groups. However, the differences remain significant after adjustment for FM between normal weight group with low weight, overweight and obesity groups (p<0.05). After adjustment for weight, the differences remain significant between normal weight group with low weight, overweight and obesity groups in women (p<0.05) but not in men.Conclusions This study supports the conclusion that overweight individuals have greater hip neck strength in comparison with normal weight controls, and femoral neck bone strength is adapted with "active stress" provided by muscle. Lean mass is a major determinant for femoral neck strength in all subjects.更多还原