双能X射线骨密度仪不同测量方式检测大鼠骨密度的准确性

背景:双能X射线骨密度仪是诊断骨质疏松症的金标准,但采用其系统默认方式测量小动物骨密度误差很大。目的:观察双能X射线骨密度仪不同测量方式对大鼠骨密度测量准确度的影响。方法:应用双能X射线骨密度仪对六七月龄雌性SD大鼠进行全身扫描,分别采用自定义手动矩形方式、手动椭圆形方式与系统默认标准方式依次测量大鼠的全身、头部及脊柱部位的骨密度。结果与结论:手动椭圆形方式与系统默认方式测得的大鼠全身、头部和脊柱的骨密度差异无显著性意义(P>0.05),而手动矩形方式与系统默认标准方式间差异有显著性意义(P<0.01)。双能X射线骨密度仪应用手动椭圆形方式与系统默认标准方式对测量结果影响不大,但手动矩形测量方式误差较大。提示手动椭圆形方式可作为小动物骨密度测量后的分析方法之一。     

双能X线骨密度仪与定量CT测量骨密度的比较

骨质疏松必须有症状、体征、实验室检查(骨代谢生化和激素指标等)，X线片等方法的帮助，特异的定量的诊断骨质疏松的手段是骨密度测量，没有骨密度的支持是不能诊断骨质疏松。有创的骨组织形态计量法的手段难于在临床上推广，目前广泛应用的是各种无创性骨密度测量手段。故而临床中骨密度的测定目前主要是双能X线骨密度仪(dual-X-ray absorptiometry，DXA)与定量CT，但DCA与定量CT测量骨密度的争论由来已久。文章拟从两者的测量方式、原理及临床运用中遇到的问题作一综述。     

不同条件髋部骨骼的短期精密度差异:双能X射线骨密度仪测量

背景:对骨密度测量的方法有多种多样,但对髋部不同程度骨质疏松测定方面的质量控制国内目前尚未见报道.目的:比较应用DPX-MD双能X射线骨密度仪测量髋部不同程度骨质疏松骨的短期精密度差异.方法:根据骨质疏松程度分类标准,将20例受试者分为骨量正常组、骨量减少组、骨质疏松组、严重骨质疏松组.1个附带软组织的死体髋部由川北医学院人体解剖实验室提供.采用DPX-MD双能X射线骨密度仪测量每例受试者髋部骨骼的骨密度,1次/d,连续测定5 d.各部位的骨密度值以均值±标准差表示,由不同骨密度的均值除标准差得到变异系数,即短期精密度.结果与结论:髋部的股骨颈、Ward三角区、大转子、大转子内区、髋部总体这5个区域比较,各组每例受试者均为髋部总体骨密度的变异系数最小,说明髋部总体区的短期精密度最好,股骨颈次之,Ward三角区骨密度的变异系数最大,这可能与其难准确定位有关.骨量正常组骨密度变异系数小于骨量减少组、骨质疏松组、严重骨质疏松组,其短期精密度最好,死体各区域骨密度的变异系数值均大于上述4组,说明其短期精密度最差.结果提示不同条件髋部骨骼的短期精密度存在差异,在临床药物疗效观察过程中进行骨密度检测时,可选择影响最小的髋部总体区域,其次为股骨颈部位.     

双能X线骨密度仪在15cm水深中测量骨密度的准确性

目的：探讨双能X线骨密度仪(dual energy X-ray absorptiometry，DXA)测量骨密度的准确性。方法：用DXA(前后位扫描)测量5具浸泡在15cm水深中的猪腰段脊柱，共计20例椎骨，计算测量的结果与灰重及灰重密度相关性。结果：骨矿含量与灰重呈显著正相关性(r=0．95，P&;lt;0．01)，而骨密度与灰重无明显相关性(r=0．41，P&;gt;0．05)。结论：DXA测量骨密度中骨矿含量较准确，而骨密度较差。     

双能X线骨密度仪椎体骨密度测定骨质疏松症临床价值分析

目的:对骨质疏松症应用双能X线骨密度仪测定锥体骨密度的临床疗效展开分析。方法:选择我院2018年11月-2019年期间收治的80例骨质疏松患者作为研究对象,对所有患者均实施双能X线骨密度仪,测定不同年龄阶段椎体骨质疏松的情况。结果:不同年龄阶段骨质量测定的均值存在差异。根据骨密度的测定将其分为两个标准,骨密度≤x-2.0SD,骨密度≤x-2.5SD。经测定发现,所有患者的骨密度均不足x-2.0SD,其中65例骨密度不足。随着年龄的增长,骨质量均差的值越小。结论:对骨质疏松症应用双能X线骨密度仪测定锥体骨密度能够起到较高的临床应用价值,为临床治疗提供详细的数据,诊断价值较高。     

双能X射线骨密度仪测量离体羊股骨骨折端及钢板对接骨折端的骨密度

背景：目前,羊已逐渐成为骨质疏松研究中很有前途的动物模型。目的：采用双能X射线骨密度仪测量羊股部骨折断端及全部骨密度,探讨双能X射线骨密度仪测量过程中的准确度和精确度。方法：对双能X射线骨密度仪自带的Lunar腰椎模型扫描10次/d,确定机器准确度,再连续扫描25d,根据所测数据建立Shewhart控制图。选取3只羊中5根股骨进行7次重复扫描,采用骨密度仪自带的小动物分析软件分析羊股部骨折断端的骨密度、全部的骨密度,计算其精密度。另外选取4只羊8根股骨,用2种钢板对骨折断端固定,分析骨密度及骨矿含量的变化。结果与结论：双能X线骨密度仪的准确度为-1.0%,离体羊股部骨折断端及全部的骨密度测量精密度为0.005～0.537g/cm2。股骨全部骨和骨折断端密度的短期精密度分别为0.8%和1.5%,股骨全部和骨折断端骨矿物含量的短期精密度为0.9%和7.5%。不同钢板固定后的羊股骨骨密度、骨矿含量差异无显著性意义。结果证实,双能X射线骨密度仪能准确测量离体羊股骨的骨密度,但在骨折断端骨矿含量精密度分析有一定的误差。     

双能X射线骨密度仪测量离体羊股骨骨折端及钢板对接骨折端的骨密度

背景:目前,羊已逐渐成为骨质疏松研究中很有前途的动物模型。目的:采用双能X射线骨密度仪测量羊股部骨折断端及全部骨密度,探讨双能X射线骨密度仪测量过程中的准确度和精确度。方法:对双能X射线骨密度仪自带的Lunar腰椎模型扫描10次/d,确定机器准确度,再连续扫描25d,根据所测数据建立Shewhart控制图。选取3只羊中5根股骨进行7次重复扫描,采用骨密度仪自带的小动物分析软件分析羊股部骨折断端的骨密度、全部的骨密度,计算其精密度。另外选取4只羊8根股骨,用2种钢板对骨折断端固定,分析骨密度及骨矿含量的变化。结果与结论:双能X线骨密度仪的准确度为-1.0%,离体羊股部骨折断端及全部的骨密度测量精密度为0.005～0.537g/cm2。股骨全部骨和骨折断端密度的短期精密度分别为0.8%和1.5%,股骨全部和骨折断端骨矿物含量的短期精密度为0.9%和7.5%。不同钢板固定后的羊股骨骨密度、骨矿含量差异无显著性意义。结果证实,双能X射线骨密度仪能准确测量离体羊股骨的骨密度,但在骨折断端骨矿含量精密度分析有一定的误差。     

双能X线骨密度仪检测中老年男性不同部位骨密度及骨质疏松检出率的研究

目的:探讨双能X线骨密度仪检测中老年男性不同部位骨密度及骨质疏松检出率.方法:选取2017年1月—2021年1月间80例在我院行双能X线骨密度仪检测的中老年男性作为观察对象,比较中老年男性腰椎与髋关节部位骨密度和骨质疏松检出率的差异.结果:80例中老年男性腰椎与髋关节部位骨密度值进行比较,50至69岁年龄组髋关节部位骨...     

双能X线骨密度仪测量不同条件椎骨的精度差异初探

目的探讨DPX-MD双能X线骨密度仪测量腰椎铝体模、活体腰椎、死体腰椎(带软组织)骨密度(BMD)的短期精密度,以便为骨密度检测质量控制和减少误差提供依据。方法用DPX-MD骨密度仪测量铝体模和3个活体、1个死体腰椎标本,作短期精度研究。结果变异系数铝体模最小,活体以骨密度正常者变异系数较骨密度异常者小,死体最大,其L2～4变异系数各为0.131%、0.542%、1.033%、2.844%和3.442%。结论铝体模短期精度最好,活体以骨密度正常者短期精度较骨密度异常者好,死体最差。说明不同条件椎骨的精度存在差异。     

两种双能X射线吸收法骨密度仪数据共享:Challenger与Holigic仪器的交叉校正

背景：为达到数据共享的目的,不同厂家生产的双能X射线吸收骨密度仪需要进行仪器之间的校正。目的：利用峰值骨量的人群尝试确立Challenger与Holigic QDR4500型DXA之间的数据换算关系。设计、时间及地点：数据直线相关及回归分析实验,于2007-10在青岛海慈医院骨密度室完成。对象：25～35岁符合青岛地区峰值骨密度的健康成年女性30人。方法：受试者分别经法国DMS公司产的Challenger型扇形束X射线吸收骨密度仪和美国Hologic公司产的QDR-4500A型扇形束X射线吸收骨密度仪测得骨密度值。主要观察指标：通过直线相关与回归分析分别计算出L2～4正位和左侧股骨颈、大转子、Ward三角区6个骨骼区域的骨密度换算公式,并进行青岛与长沙两地区健康女性多骨骼部位骨密度数据库校正前后的比较以验证公式的可行性。结果：两种骨密度仪测定得到的数据显著相关,存在线性关系。校正之前,青岛地区女性髋骨骨密度高于长沙地区;校正之后两地区骨密度无显著性差别。结论：峰值骨量人群可用于Challenger与Holigic QDR4500型双能X射线吸收骨密度仪之间的校正。     

体重指数与骨密度的关系

目的分析体重指数(BMI)与骨密度的关系.方法对2395例腰椎前后位和髋部骨密度检查结果的T值与体重指数进行统计学相关回归分析.结果无论总体分析或按年龄组分析都显示骨密度T值与体重指数呈线性正相关.低体重指数者(BMI≤20)骨密度T值低于较高体重指数者(BMI>20),差异具有显著性.骨密度T值随体重指数变化在髋部较脊柱更明显.结论体重指数与骨密度T值呈正相关,低体重指数与骨质疏松的发生有关.     

Predictive value of bone mineral density and Singh index for the in vitro mechanical properties of cancellous bone in the femoral head.

OBJECTIVE: The purpose of this study was to assess the validity of two methodically different radiological parameters, bone mineral density and Singh Index, for the prediction of mechanical properties in femoral cancellous bone. DESIGN: Coherence between in vitro evaluation of mechanical properties and bone mineral density on a femoral bone slice, combined with clinical determination of Singh Index on ordinary X-rays. BACKGROUND: It is accepted that bone densitometry yields excellent prediction of mechanical bone quality, but is considered to be an expensive and not widely available method for routine diagnostics in clinical practice. In contrast, determination of Singh Index is an inexpensive and simple technique, but its predictive value for bone mechanics is still controversially discussed. METHODS: We used cortically confined bone slices from 33 femoral heads. Bone mineral density was measured using quantitative computed tomography. Strength and elastic modulus were assessed by mechanical testing in up to 39 circular positions on each slice. Singh Index was evaluated on ordinary X-rays of the hip by two independent readers. RESULTS: Bone mineral density showed strong correlations with strength (r=0.86) and good correlations with elastic modulus (r=0.68). Singh Index correlated well with strength (r=0.70), but only moderately with elastic modulus (r=0.52). CONCLUSIONS: The strong validity of bone mineral density in predicting mechanical bone quality was confirmed. Singh Index assessment permits a rough estimation of mechanical strength in particular and can therefore be used for first estimations of mechanical bone quality, provided that readings were performed by experienced clinicians. RELEVANCE: Reduced mechanical bone quality induces an increase in fracture risk. Whenever performed, bone mineral density measurement allows an excellent evaluation of the mechanical properties of cancellous bone in the hip and can be recommended for screening evaluations. The assessment of Singh Index on ordinary X-rays of the hip is an inexpensive and simple method, and allows a rough estimation of the mechanical quality of the femur. However, due to its subjective character, its predictive value for the mechanical quality of bone in individual patients remains uncertain.     

股骨近端髓腔闪烁指数与股骨颈骨密度的关系

背景：髋关节成形患者具有较高的骨质疏松症患病率,骨质疏松症影响假体存活率,髓腔闪烁指数与骨密度均随年龄变化。目的：探讨股骨近端髓腔闪烁指数与股骨颈骨密度的关系,提高对骨质疏松症的关注。方法：回顾性研究57例髋关节成形患者的骨盆X射线正位片的股骨近端髓腔闪烁指数和股骨颈骨密度,探讨二者的相关性。结果与结论：57例髋关节成形患者的股骨近端髓腔闪烁指数为1.8-4.8（3.1±0.7）;髓腔闪烁指数4.7者1例。年龄对髓腔类型有影响,〉60岁组烟囱型髓腔显著性多于≤60岁组,髓腔闪烁指数≥3组的骨密度显著高于髓腔闪烁指数60岁组患者的股骨颈骨密度为（0.590±0.092） g/cm2,显著低于≤60岁组患者的股骨颈骨密度（0.751±0.235） g/cm2（P=0.000）,比较发现随骨密度降低,髓腔闪烁指数均值变小。因此股骨颈骨密度与髓腔闪烁指数显著相关。     

Biomechanical study on femoral neck fracture fixation in relation to bone mineral density

Twenty pairs of fresh-frozen cadaveric femurs were used in the study. The left femurs were used as control for the mechanical testings and bone mineral content scans, the right femurs were divided into two experimental groups, i.e. 'fractured' group and 'healed' group. In the 'fractured' group, twelve right femurs were osteotomized at the plane perpendicular to the femoral neck shaft axis, through the mid-cervical area of the femoral neck. The artificially created fractures were fixed with the AO dynamic hip screw system using a 4-hole plate and a compression screw. In the 'healed' group, the dynamic hip screws were applied to eight intact right femurs to simulate healed fractures. Bone mineral density scans and mechanical testings were performed on all the femurs. Good correlation was observed between bone mineral density and femoral neck strength in the control group. There was a decrease of 43.5% in strength in the 'fractured' group when compared to the control group. However, in the 'healed' group the failure load was found to be 15.2% lower than the control group. The femoral fixation strength in the 'fractured' and 'healed' groups had good correlation with the bone mineral density. RELEVANCE--:Results from this study indicated that bone mineral density is an important predictive factor in fracture fixation failure. Therefore it may be appropriate to consider the bone mineral density of a patient with proximal femoral fracture treated with fixation devices, as a criterion in prescribing a more protective postoperative management, with respect to weight bearing protocol.     

Relationship between low bone mineral density and exercise-induced myocardial ischemia

OBJECTIVE: To evaluate the relationship between bone mineral density (BMD) and ischemic heart disease and exercise capacity, as assessed by stress testing. PATIENTS AND METHODS: We retrospectively reviewed entries in the echocardiography database for 28,048 consecutive patients who underwent exercise echocardiography for standard clinical indications between August 1, 1998, and October 1, 2003, to determine which of these patients had also undergone dual-energy x-ray absorptiometry to measure femoral neck BMD before the procedure. Of the 1194 patients meeting both criteria, 28 were excluded because of missing data and 24 because they were tested with an exercise protocol other than the Bruce protocol, leaving 1142 patients to be included. RESULTS: Of the included study patients, 643 (56%) had a T score of -1.0 or less (mean age +/- SD, 67 +/- 0 years; 87% women), and 499 (44%) had a T score greater than -1.0 (60 +/- 10 years; 90% women). For every 1-unit decrease in femoral neck T score, a 0.23 minute decrease in treadmill exercise duration was observed, once values had been adjusted for age and other patient characteristics (95% confidence interval [CI], 0.11-0.35; P<.001). Furthermore, for every 1-unit decrease in T score, there was a 22% increased risk of myocardial ischemia after adjustments (hazard ratio, 1.22; 95% CI, 1.06-1.41; P=.004). Overall, after adjustments, patients with a BMD of -1.0 or less who were referred for exercise echocardiography had a 43% greater risk of myocardial ischemia than did patients referred with normal BMD (hazard ratio, 1.43; 95% CI, 1.06-1.94; P=.02). CONCLUSIONS: Lower BMD is associated with myocardial ischemia and decreased exercise capacity during exercise echocardiography. Persons with low BMD who present with symptoms suggestive of cardiovascular disease are more likely to have myocardial ischemia than are those with normal BMD.     

Relationship between bone mineral density and biochemical markers of bone turnover in hemodialysis patients

End-stage renal disease is closely associated with changes in bone and mineral metabolism. In recent times, osteoporosis has become important among hemodialysis (HD) patients. In this study, the investigators sought to evaluate the relationship between bone mineral density (BMD) and biochemical markers of bone turnover among HD patients. A total of 70 uremic patients on a maintenance HD program for at least 1 y were enrolled in the study. All patients were treated with conventional bicarbonated HD for 5 h through the use of low-flux hollow-fiber dialyzers. Bone densitometry was measured by dual energy x-ray absorptiometry in the lumbar spine (LS) and the femoral neck (FN). BMD was classified according to World Health Organization criteria on the basis of BMD T scores. Biochemical bone turnover markers such as calcium, phosphorus, ionized calcium, intact parathyroid hormone, alkaline phosphatase, plasma bicarbonate, blood pH, serum albumin, and hematocrit levels were measured before the HD session in the morning. Male patients (n=37; 52.9%; mean age, 46.2+/-17.0 y) were assigned to a single study group, and female patients (n=33; 47.1%; mean age, 44.0+/-13.1 y) to another. Mean duration of HD treatment was 33.7+/-28.5 mo in females and 33.0+/-26.0 mo in males. Among all patients, BMD T scores in the osteopenia/osteoporosis range were observed at the LS in 58 patients (82.8%) and at the FN in 45 patients (64.3%). According to BMD measurements in FN T score, 10% of patients (n=7) were osteoporotic, 54.3% (n=38), osteopenic, and 35.7% (n=25), normal. On the other hand, in LS T score, the results were 47.1% (n=33) osteoporotic, 35.7% (n=25), osteopenic, and 17.1% (n=12), normal. No statistically significant association was found in osteopenia/osteoporosis between sexes according to FN and LS T score (P=.542, P=.267, respectively). No significant relationship was noted between BMD and biochemical markers of bone turnover. A positive correlation was found between FN T scores of BMD and age (r=.413, P=.000). BMD T scores within the range of scores for osteopenia/osteoporosis were observed in 78.5% of patients at the LS and in 58.5% of patients at the FN. The investigators concluded that no correlation could be found between markers of bone turnover and bone mass measurements in both skeletal regions. LS T score results were worse than FN T score results. Elevated alkaline phosphastase levels combined with high intact parathyroid hormone levels are predictive of renal osteodystrophy but not of adynamic bone disease/osteoporosis.     

Physical fitness is a major determinant of femoral neck and lumbar spine bone mineral density.

The relationship between physical fitness and bone mass in the femoral neck, lumbar spine, and forearm was studied in 84 normal women. Femoral neck and lumbar spine bone mineral density and forearm bone mineral content were estimated by absorptiometry. Fitness was quantitated from predicted maximal oxygen uptake. Femoral neck and lumbar bone mineral density were significantly correlated with fitness as well as age and weight. In the 46 postmenopausal subjects, fitness was the only significant predictor of femoral neck bone mineral density, and both weight and fitness predicted the lumbar bone mineral density. These data represent the first demonstration of a correlation between physical fitness, and, by implication, habitual physical activity, and bone mass in the femoral neck; they also support the previous reported correlation between lumbar bone mass and physical activity. The data suggest that increased physical fitness may increase bone mass at the sites of clinically important fractures in osteoporosis.