DXA椎体骨折评价在骨质疏松诊断中的意义

目的比较双能X线骨密度仪的椎体骨折评价(vertebral fracture assessment,VFA)中Genant半定量法和6点定量法对椎体压缩诊断的差异,探讨联合应用VFA在骨质疏松诊断中的意义。方法对85名主诉有腰背痛或身高变矮的患者行骨密度检查(男12例,女73例),平均年龄68.1±10.4岁;女性绝经年龄49.4±3.4岁。同时应用VFA软件分析椎体是否存在压缩,分别采用Genant半定量法和6点定量法进行分析。结果骨密度采用世界卫生组织(WHO)诊断标准,诊断骨质疏松66人,低骨量14人,5人骨量正常,骨质疏松诊断率为77.65%。采用Genant半定量法判断椎体Ⅰ~Ⅲ度压缩76人,6点定量法判断椎体压缩64人,两种方法的椎体压缩诊断率有差异(P0.01),两种方法的Ⅱ、Ⅲ度椎体压缩的诊断率无差异(P0.05)。6例通过骨密度T值诊断的非骨质疏松患者用VFA分析诊断有椎体骨折(压缩Ⅱ~Ⅲ度),应用T值联合VFA椎体压缩Ⅱ~Ⅲ度诊断的骨质疏松率为84.71%,与单独使用T值相比诊断率有差异(P0.05)。结论使用双能X线骨密度仪进行椎体骨折评价时,Genant半定量法和6点定量法对椎体压缩程度为Ⅱ、Ⅲ度的诊断率无差异、一致性好。骨密度检查时联合行VFA可增加骨质疏松的诊断率。     

DXA诊断椎体压缩性骨折的应用进展

椎体压缩性骨折不仅是骨质疏松的主要临床表现之一,而且在预测骨折风险中具有重要意义,双能X线骨密度吸收仪(DXA)从最初的一种定量测量仪器发展到可以进行成像,目前已经可以用椎体侧位DXA成像来诊断椎体骨折并进行椎体骨折评估,可以更好的了解骨骼状态,而且放射暴露比普通X片低得多,本文就DXA在椎体压缩性骨折诊断方面的进展综述如下.     

DXA在诊断主动脉钙化中的应用进展

双能X线骨密度吸收仪(DXA)通常被用于测定骨密度(BMD)以诊断骨质疏松,近年研究发现,DXA同时应仔细观察主动脉有无钙化,而主动脉钙化是冠心病的重要危险因素,发现异常者应结合被检者的年龄、冠心病风险因素等情况提出进一步检查的建议。这样,在检测骨密度的同时检测主动脉的钙化,无论是对骨质疏松还是冠心病的发生均可以起到早期诊断、早期治疗的目的 。     

DXA预测髋骨骨折的应用进展

髋骨骨折不仅与骨密度有关,还与其几何结构有关.用双能X线吸收测定仪(DEXA) 除可以测量股骨上段骨密度外,还可以测量评价髋部的几何形态(如髋骨轴长度、股骨颈干角、股骨颈宽度及股骨颈上部局部骨密度等)及髋骨结构或强度分析等生物力学参数,更好的预测髋骨骨折.     

超高龄人群脊柱与髋部骨密度差异及其在髋部骨折风险评估中的价值

目的通过比较超高龄人群(年龄≥80岁)脊柱与髋部骨密度(BMD)差异, 分析不同部位BMD在超高龄髋部骨折风险评估中的价值。方法采用回顾性研究方法, 选取2017年11月至2022年2月在郑州大学第一附属医院骨科收治的超高龄髋部骨折患者52例作为观察组;选取同期体检中心超高龄体检患者52例作为对照组。通过组间比较分析两组患者一般资料、双能X线吸收检测法(DXA)测量得到的脊柱和髋部BMD差异;通过组内比较分析两组患者自身脊柱与髋部BMD的差异。计量资料采用t检验, 计数资料采用χ2检验。结果组间比较显示, 观察组和对照组患者基线资料差异无统计学意义;观察组患者腰3椎体(L3)[(-2.7±1.5)比(-1.8±2.2), t=-2.275, P<0.05]、腰4椎体(L4)[(-2.4±1.5)比(-1.6±2.1), t=-2.137, P<0.05]、腰1～4椎体整体值(L1～4)[(-2.7±1.4)比(-2.0±1.9), t=-2.023, P<0.05]以及全髋部(TH)[(-3.0±1.1)比(-2.2±1.3), t=-2.618, P<0.05...     

定量超声检测对绝经后骨质疏松症的应用价值

目的评价定量超声检测技术(QUS)对绝经后骨质疏松症的临床应用价值。方法 88例绝经后女性分别使用QUS测量左跟骨T值、双能X线吸收法(DXA)测量L1-4及髋部骨密度、T值,采用Spearman分析两种检测方法相关性。以DXA法诊断骨质疏松症(OP)为金标准,分析QUS诊断OP的ROC曲线下面积、cutoff、灵敏度、特异度、符合率、Youden指数。结果相关分析显示,QUS测量左跟骨与DXA测量L1、L2、L3、股骨颈、大转子、全髋T值相关系数分别为0.244、0.252、0.371、0.485、0.539、0.506(P0.05或P0.01);ROC曲线下面积0.669,以QUS测量T值-2.35为cutoff,QUS诊断OP的灵敏度、特异度、符合率、Youden指数分别为69.1%、65.0%、64.77%、0.341。结论 QUS与DXA检测骨密度存在相关性,可作为OP的筛查工具,但诊断效能一般,不可替代DXA检查。     

骨质疏松与老年髋部骨折

目的观察60岁以上的老年人与同性别年轻人骨密度峰值的差别,老年髋部骨折患者与同年龄组健康老年人骨密度的差异,及近11年来老年髋部骨折发生的一般规律。探索老年髋部骨折与骨质疏松的关系。方法测量20~35岁年龄组正常男性和女性的腰椎、股骨颈、Ward三角及大转子区的骨密度值;测量60岁以上健康老年男性及女性各年龄组的骨密度值;测量60岁以上新入院髋部骨折男、女性患者的骨密度值。所有结果均进行统计学处理。统计近11年来收治的445例60岁以上髋部骨折患者的年龄、性别分布规律。结果60岁以上的男、女性老年人与同性别年轻人骨密度比较,差异有显著性意义(P<0.01);健康老年男性骨密度明显高于同年龄组女性(P<0.01);健康老年男、女性骨密度明显高于同年龄组髋部骨折患者(P<0.01);对近11年来收治的445例老年髋部骨折患者的性别、年龄进行比较,差异无显著性意义。结论虽然老年骨折常由外伤引起,但骨质疏松是老年人骨折的重要内在因素;尽管老年男性比女性骨密度高,但两者的骨折机会及骨折发生率基本相同。     

糖皮质激素对成年大鼠骨量的影响

目的利用双能X线吸收法(DXA)探讨成年大鼠接受糖皮质激素后骨量变化的规律。方法 21只44周龄SD雌性大鼠分别假性去卵巢+未注射糖皮质激素(SHAM组)、摘除双侧卵巢(OVX组)或注射甲基强的松龙[2.5 mg/(kg·d)](PRED组),应用扇形束DXA(QDR-4500A)每4周测定一次全身骨密度(BMD)、骨矿含量(BMC)、骨骼面积(AREA);术后12周处死,测定离体腰椎、股骨、胫骨及其兴趣区的BMD、BMC、AREA。压缩试验测定第二腰椎最大载荷和弹性模量。结果 (1)术后8周开始OVX组体重显著重于同龄SHAM组(8周时,P0.05,12周时P0.01),术后4周开始PRED组体重显著轻于同龄SHAM组(P0.05);(2)术后12周OVX组整体BMC显著高于SHAM组(P0.05),术后8、12周OVX组整体BMC显著高于PRED组(P0.05);(3)术后12周OVX组离体第5、6腰椎BMD及第6腰椎BMC显著低于SHAM组和PRED组(P0.05),PRED组离体各腰椎BMD、BMC、AREA与SHAM组无明显差异;(4)术后12周与SHAM组比较,OVX组离体股骨(-7.42%)、股骨远端(-10.85%)和近端(-6.92%)、胫骨近端(-11.40%)BMD显著降低(P0.05),其中股骨、股骨远端、胫骨近端BMC也显著降低(P0.05);(5)术后12周与SHAM组比较,PRED组离体股骨及各区BMD、BMC、AREA无显著性差异,整体胫骨及各区BMD无显著性差异;(6)术后12周与SHAM组比较,OVX组及PRED组胫骨中远端骨量增加;(7)与SHAM组比较,OVX组最大载荷和弹性模量显著降低,PRED组最大载荷显著降低。结论成熟期大鼠接受甲基强的松龙后,皮质骨和松质骨骨量没有显著变化,DXA检查难以发现其骨丢失情况;力学性能改变提示糖皮质激素更多的是引起骨质量的改变而导致了力学性能的下降及骨折的发生。     

DXA在体成分测定方面的应用进展

在代谢综合征等疾病状态下,体成分测定比体重更有意义。体成分包括体内脂肪组织和瘦组织分布及百分组成,其测定方法有二分法和三分法等。双能X线骨密度测定(DXA)属于三分法,精确度高完全可以替代CT测量腹部和内脏脂肪。     

北京地区3859名体检人群骨密度调查及骨量异常患病率分析

目的调查北京地区健康体检人群骨密度的情况以及骨量减少和骨质疏松的患病率,为骨质疏松症的防治提供参考。方法选择2017年1月至2018年12月在中日友好医院健康体检中心进行健康体检的人群,排除继发性骨质疏松症及其他影响骨代谢的因素,共3859名。其中男性2067名,女性1792名。年龄20~83岁,平均年龄(51.29±11.18)岁,按性别及年龄每10年一组。采用美国GE公司的LUNAR Prodigy双能X线骨密度仪测量受试者腰椎1~4正位及股骨颈和全髋的骨密度。分析各组不同部位骨密度情况及骨量异常(包括骨量减少和骨质疏松)的患病率。采用SPSS 22.0统计软件进行分析,以P<0.05为差异有统计学意义。结果①男性腰椎1~4骨密度峰值在20~29岁,股骨颈和全髋骨密度峰值在30~39岁。女性各部位骨密度峰值均在30~39岁。②随年龄增长,男性和女性骨量异常患病率均呈上升趋势,50岁以上女性骨量异常患病率显著上升,明显高于同年龄组男性。③30~59岁男性和女性腰椎骨量异常患病率均明显高于髋部;70岁以上男性和60岁以上女性髋部骨量异常患病率明显高于腰椎。结论中老年人群尤其是绝经后女性是骨质疏松症的高危人群;老年人群的骨质疏松筛查可以考虑选择髋部骨密度为主。     

In vitro comparability of dual energy X-ray absorptiometry (DEXA) bone densitometers

Summary Six Hologic QDR-1000 DEXA bone densitometers at different centers across the USA were compared to determine the intermachine variability. Nine scans in succession were acquired on each machine using a single anthropomorphic lumbar spine phantom (manufactured by Hologic). Values for BMC, area, and BMD were recorded for each measurement. Means, standard deviations (SD), and coefficients of variation (CV) were calculated for each machine. All the CVs (BMC, area, BMD) were less than 1% (range 0.3%–0.6%). The CV of the means at the six sites were 0.4%, 0.6%, and 0.5% for BMC, area, and BMD, respectively. Although several significant differences for BMC, area, and BMD were noted by ANOVA between machines at different sites, the difference between the highest and lowest means of the individual machines was only 1.1%, 1.31%, and 1.07% for BMC, area, and BMD. The small variations between the DEXA systems are encouraging for researchers involved in multicenter trials in which data are pooled.     

A comparison of spinal quantitative computed tomography with dual energy X-ray absorptiometry in European women with vertebral and nonvertebral fractures

Quantitative computed tomography (QCT) was compared to dual X-ray absorptiometry (DXA) measured in the lumbar spine of 508 European women defined as normal without fracture (NoF), or osteoporotic (OP), with either vertebral fracture (VF), or peripheral fracture (PF). The correlations between QCT and DXA BMD measurements were significantly different in normal and in osteoporotic patients, indicating that the two exams do not measure the same bone aspects. According to ROC curves results, QCT Z-scores separate OP from NoF with better sensitivity than all other measurements. A threshold to differentiate OP from NoF was chosen at Z-score=−1 for DXA-BMD and −1.5 for QCT-BMD. VF patients showed a highly significant decrease in BMD by DXA or QCT. PF patients revealed measurements lower than those of normal subjects but greater than those of VF, calling into question the idea of a diffuse osteoporosis causing nonvertebral fractures that is measurable by spinal DXA or QCT. DXA is weakly dependent upon age, and T-score or Z-score are equivalent for evaluating osteoporosis. QCT depends greatly upon age, and Z-score appears to be more efficient.     

双能X线和单光子吸收法及定量超声诊断骨质疏松症的比较

了解三种方法诊断骨质疏松症（ＯＰ）之间的关系。方法应用双能Ｘ线吸收法（ＤＸＡ）和单光子吸收法（ＳＰＡ）及定量超声（ＱＵＳ），同时随机测量２９４例受试者腰椎后前位和侧位、左侧髓部和前臂骨矿密度（ＢＭＤ）及右侧胫骨超声速度（ＳＯＳ）。结果ＤＸＡ和ＳＰＡ测量桡骨ＯＰ的检出率分别为２５．９％和２１．４％，ＤＸＡ测量腰椎后前位、侧位、侧位兴趣区、Ｗａｒｄ’ｓ区和股骨颈ＯＰ检出率分别为１６．０％、２２．８％、２６．２％、１９．４％和４．４２％，ＱＵＳ的ＯＰ检出率为１７．７％。三种方法及不同部位之间的测量结果呈显著相关（ｒ＝０．４９４～０．９６７，Ｐ＜０．０１）。ＤＸＡ测量前臂１／３处ＢＭＤ显著高于ＳＰＡ。诊断ＯＰ的齐同率ＤＸＡ各部位相互之间平均为４０．１％±１５．５％，ＤＸＡ与ＳＰＡ平均为４８．４％±１９．０％，ＱＵＳ与ＤＸＡ和ＳＰＡ平均为３８．８％±１０．２％，各平均值之间无显著差异。结论ＯＰ的检出率取决于受检部位，腰椎侧位兴趣区和挠骨是检出率最高的部位，股骨颈和尺骨是最低的部位。ＳＰＡ与ＤＸＡ测量前臂ＢＭＤ高度相关，诊断结果无显著性差别。     

Reproducibility of lateral spine scans using dual energy X-ray absorptiometry

Summary Reproducibility of lateral spine dual energy X-ray absorptiometry (LAT DEXA) scans using a Lunar DPX-L scanner was assessed in a cadaveric phantom and in patients. One hundred phantom measurements over 7 months demonstrated a longitudinal stability of 1.7% (coefficient of variation, CV). Additional scans were performed with the phantom rotated by up to 20° in each of the three orthogonal planes to assess the effects of variable patient positioning. Horizontal and vertical rotation of the spine had little effect on the estimated bone mineral density (BMD), however, axial rotation of greater than 8° led to errors in the BMD measurement. One hundred consecutive patients had two lateral scans performed within 1 month. BMD (range 0.10–1.6 g/cm²) was determined for each scan by one operator. Significant overlap from ribs and pelvis was often seen with L2 and L4 vertebrae but one vertebra (L3) could be measured in every case. Intraoperator and interoperator variability was assessed by three experienced operators, each analyzing 10 patients' scans on five separate occasions, and was found to be less than 1.1% for a single vertebra. BMD estimation of vertebral bodies and midslices by lateral DEXA scans (CV% of 3.8% and 4.6%) have a 95% confidence interval of 0.074 g/cm² and 0.096 g/cm², respectively for two vertebrae. This variability is due mainly to axial rotation, with operator variability, horizontal rotation, and vertical rotation having little effect on BMD estimation.     

Comparative assessment of bone mineral density of the forearm using single photon and dual X-ray absorptiometry

Summary Forearm bone mineral density (BMD) was measured at proximal and distal sites by ¹²⁵I single photon absorptiometry (SPA) and by dual energy X-ray absorptiometry (DXA) in 67 consecutive subjects, aged 18–75 years. Correlations and regression equations between these two techniques were determined. All forearm measurements were significantly correlated with each other (r=0.599–0.926; P0.0001). Although SPA and DXA correct for fat in different ways, we found similar correlation and regression equations in women with body mass index measurements above and below the mean. In addition, forearm measurements by both techniques were moderately correlated with vertebral spine and hip BMD. We conclude that overall, SPA forearm measurements in a population can be calibrated to DXA measurements if necessary, and that DXA forearm measurements are as predictive of the remainder of the skeleton as SPA measurements.     

Bone mineral density of the distal femur following uncemented total knee arthroplasty: a two-year follow-up of 11 knees using dual energy X-ray absorptiometry

Abstract In a prospective study, we evaluated the adaptive bone remodelling pattern of the distal femur using dual energy X-ray absorptiometry (DEXA) after total knee arthroplasty (TKA). Eleven patients underwent TKA with insertion of an Interax total knee system (Howmedica) because of primary osteoarthrosis of the knee. All patients received an uncemented femoral component with an uncoated cast-mesh ingrowth surface. The components had a 20-mm long central peg placed anteriorly just behind the anterior flange. DEXA scans were performed postoperatively at 2 weeks and at 3, 6, 12 and 24 months in the mediolateral plane of the distal femur and in the anteroposterior plane of the distal tibia and fibula. Compared to the immediate 2-week postoperative bone mineral density (BMD) value, we found no significant changes in BMD in 4 regions of interest (ROI) in the distal femur during the 2-year follow-up at 3 months. A temporary but significant decrease in BMD of 11.2% (95% CL, -17.3% to -5.0%) was observed in the most distal ROI just posterior to the fixation peg. Bone mineral content (BMC) of the distal tibia and fibula showed no significant changes in the operated and contralateral legs during the follow-up. The adaptive bone remodelling of the distal femur after TKA using an uncemented femoral component not previously examined by DEXA induced only a very limited and temporary loss of bone mineral.     

Body composition in children with renal disease: use of dual energy X-ray absorptiometry

Dual energy X-ray absorptiometry (DEXA) is a non-invasive accurate method which estimates bone mineral content and density (BMD), as well as fat (FM) and lean (LM) body mass. This method was used in control children in order to establish normal values for BMD of lumbar spine and whole body composition {logistic curves, general equation E=k+K/[1+exp(-A)]}. In children with chronic renal failure (CRF), LM correlated with the urinary excretion of creatinine (r=0.97,P=0.0001) independently from glomerular filtration rate. However, the assessment of LM by DEXA must take into account the hydration level, since there is a positive correlation between fluid loss and reduction in LM in children on hemodialysis (r=0.98,P=0.0001). After renal transplantation, a significant loss of BMD (median –9.2%), was observed at 6 months which returned to 95% of pretransplant values by the end of the 1 st year. Maximal changes in LM and FM occurred during the first 3 months (–7.8% and +7.2%, respectively) and may be due to steroids; these should be influenced by physical activity since FM correlated inversely with maximal oxygen consumption (r=0.69P=0.0001). Recombinant growth hormone treatment could also increase LM and decrease FM, as shown in 9 patients. DEXA appears therefore to be a reliable method for evaluating therapeutic interventions affecting nutritional status in children with CRF.     

Dual X-ray absorptiometry for the evaluation of bone density from the proximal femur after total hip arthroplasty: Analysis protocols and reproducibility

Summary Dual X-ray absorptiometry (DXA) instruments are now able to evaluate bone mineral density (BMD) of bone surrounding metal implants. The assessment of BMD around prosthetic components could provide additional information for the follow-up of total hip arthroplasty (THA). In this study, we evaluated the potential application of DXA in the field of THA. BMD was measured in the proximal femur of both THA and THA-free sides in 14 postmenopausal women 6–18 months after THA. The explored segment was divided into seven zones as proposed by Gruen et al. [18]. The precision error of BMD measurements ranged from 1.8 to 6.8% on the THA side and from 1.1 to 2% to the THA-free side. The reduction of BMD of the THA versus the THA-free side was significant in all seven zones (P < 0.01, t-test for paired data). These results showed significant differences in BMD around femoral components of THA with respect to contralateral healthy side, and demonstrate the sensitivity of DXA for detecting these changes.     

Body composition following hemodialysis: Studies using dual-energy X-ray absorptiometry and bioelectrical impedance analysis

The detection, prevention and treatment of disease is greatly facilitated by the availability of accurate and non-invasive techniques for measuring the amount and regional distribution of fat mass and fat-free mass. As differing degrees of hydration may influence these measurements, we used dual-energy X-ray absorptiometry (DXA) and bioelectrical impedance analysis (BIA) to detect changes in hydration following hemodialysis, and to determine whether fat mass, fat-free mass and bone density measurements were affected by these fluid changes. Ten subjects (7 men, 3 women) mean age 46.2 years (range 25–68 years), with renal failure had bone density, fat-free mass and fat mass measured by DXA, and total body water and fat-free mass measured by BIA, before and after hemodialysis. Thirty-two subjects had fat-free mass measured by DXA and BIA in an attempt to derive new equations (using fat-free mass measured by DXA as the reference standard) to improve the predictive value of BIA. The new equations were then used to derive the changes in fat-free mass following hemodialysis measured using BIA. In absolute terms, total tissue measured by DXA (r=0.99,p=0.01) and total body water measured by BIA (r=0.91,p=0.01) correlated with gravimetric weight. Following hemodialysis, fat mass and bone density measured by DXA were unaffacted by the fluid changes. The change in gravimetric weight was 1.8±0.3 kg,p=0.01 (mean±SEM). This change was measured as 1.9±0.3 kg by DXA, –0.9±1.0 kg by BIA using the published equation for fat-free mass, and 3.2±0.4 kg using the new equation for fat-free mass. The change in fat-free mass measured by DXA (r=0.75,p=0.01), and the change in total body water measured by BIA (r=0.70,p=0.02), correlated with the change in gravimetric weight. The change in fat-free mass measured by BIA did not correlate with the change in gravimetric weight. With the new equation, the change in fat-free mass measured by BIA correlated with the change in gravimetric weight (r=0.74,p=0.02). We conclude that absolute values, and changes in fluid in the range observed in this study, can be detected reliably by DXA. They are reflected in the fat-free mass measurement and do not confound measurements of fat mass and bone density. Although absolute values are reliably measured by BIA, the technique may have limited usefulness in detecting fluid changes. DXA thus provides a practical, non-invasive, precise and accurate method of measuring body composition which can be used as a gold standard for validating other techniques.     

Broadband ultrasound attenuation and dual energy X-ray absorptiometry in patients with hip fractures: Which technique discriminates fracture risk

There is considerable interest in predicting risk of hip fracture in order to allow targeting of preventive care. This study aimed to determine which of two methods best discriminates a hip fracture population from controls. Fifty women with fractured neck of femur, and 50 control subjects were scanned using dual energy X-ray absorptiometry (DXA) of the spine and hip and broadband ultrasound attenuation (BUA) of the os calcis. Significant differences between the two populations could be found for both DXA and BUA, with BUA showing the largest percentage difference (27%). The mean z-scores showed that BUA had the lowest, with the exception of DXA trochanter. However, no significant difference between BUA and DXA trochanter Z-scores was found. A receiver operator characteristic (ROC) analysis showed that BUA has a superior sensitivity and specificity compared with DXA measurements, with DXA of the hip being better than the spine. This retrospective study shows that BUA is a better discriminator of hip fracture than DXA lumbar spine of DXA hip, which may have important implications for predicting those at risk of future hip fracture.