对中国长沙地区女性骨密度情况的调查

目的 调查中国长沙地区女性不同骨胳部位一年龄盯关的骨密度（ＢＭＤ）、累积骨丢失和骨质疏松症（ＯＰ）的患病率。方法用ＤＸＡＱＤＲ４５００Ａ型扇形束骨密度仪测量１８１８例１５－９６岁女性腰椎前后位（ＡＰ）和仰卧侧位、髋部及前臂的ＢＭＤ《结果 按每５岁年龄分组分析的结果显示,不同骨胳部位的峰值ＢＭＤ分别发生在２０－２４岁至４０－４４岁之间,髋部的大转子和Ｗａｒｄ‘ｓ区最早（２０－２４岁）,前臂１／３处最     

薄层扫描法测定血浆中盐酸氟桂利嗪浓度及药物动力学

血浆中盐酸氟桂利嗪经硼酸缓冲液酸化后，正戊烷－异丙醇（９８：２）提取其原型，加酸使成盐溶于无机相中，再加碱后用二氯甲烷提取，样品点于硅胶ＧＦ２５４薄层板上，以环己烷－丙酮－氯仿（９：３：５）为展开剂。氟桂利嗪在２５４ｎｍ紫外灯下呈紫色斑点，Ｒｆ＝０．５４，于ＣＳ－９３０薄层扫描仪上测定，λｓ＝２１５ｎｍ、λｇ＝３１０ｎｍ，线性范围０．３￣８μｇ，平均回收率９０．０２％。用此法测定了氟桂利嗪血药浓度     

青岛地区成年女性多部位骨密度数据库的建立及骨折风险预测

目的确立青岛地区正常成年女性骨密度(BMD)的正常参考范围,建立诊断成年女性骨质疏松的多骨骼部位BMD参考值,并预测骨折的风险性。方法用双能X线骨密度仪测量868名25～83岁女性参考人群和191例骨折患者的腰椎(L_2-L_4)和左侧髋部(股骨颈、大转子、Ward’s三角区)6个骨骼区域的BMD,用8种回归模型拟合健康成年女性人群BMD随年龄的变化,找出最佳拟合的方程和建立数据库,并对骨折患者的BMD进行分析,预测骨折的风险性。结果6个骨骼区域BMD随年龄变化,不同部位骨峰值出现的时间不同,腰椎在25～29岁,髋部在40～44岁。用三次回归模型拟合程度优于其他回归模型,拟合曲线的决定系数(R~2)为0.21±0.09(P＜0.01)。骨折患者BMD明显降低,与同地区同年龄正常女性相比,BMD下降幅度有限；而与同地区正常女性峰值骨量相比,BMD下降1.6～2.5s。结论女性在45岁以后骨丢失加速。50岁以后女性BMD低于同地区峰值BMD 1.6～2.5s,其骨折风险增加。     

女性2型糖尿病患者与健康人骨密度的比较

目的　了解女性 2型糖尿病 (T2 DM)患者与健康人骨密度 (BMD)的差异。　方法　采用双能 X线吸收法 (DEXA)骨密度仪 ,测定 2 14例女性 2型糖尿病患者 (DM组 )及 110 1例年龄和体重指数相匹配的女性健康人 (对照组 )腰椎及股骨近端的 BMD。　结果　 DM患者各年龄段组腰椎及髋部各区域 BMD与相应对照组比较 ,差异均无显著性意义 (P>0 .0 5 )。DM组的 BMD与病程无相关性 [r=- (0 .0 9～ 0 .0 1) ,P均 >0 .0 5 ]。 T2 DM组和对照组各部位 BMD与年龄和绝经年限呈负相关 [r=- (0 .4 2 2～ 0 .70 5 ) ,P均 <0 .0 1]。年龄≥ 5 0岁的 DM患者腰椎骨质疏松 (OP)患病率为 2 1.9% ,低于对照组的 31.4 % (P<0 .0 5 ) ;2组之间不同骨骼部位的 OP总体患病率 T2 DM组为 (2 2 .9±14 .9) % ,对照组为 (2 5 .4± 15 .6 ) % ,差异无显著性意义。　结论　女性 T2 DM患者 ,不同部位的BMD及 OP患病率与女性健康人群相似。     

Osteoporosis in juvenile systemic lupus erythematosus: a longitudinal study on the effect of steroids on bone mineral density

Peak bone mass is an important determinant of future bone mass and of the risk of osteoporosis and subsequent fractures. Although some information concerning bone mineral density (BMD) in adults affected with systemic lupus erythematosus (SLE) is available, few data on children and adolescents have been reported. Many variables, such as duration and activity of the disease, reduced sun exposure, and steroid therapy have been suggested as risk factors in the pathogenesis of osteoporosis in SLE. In this study, we longitudinally evaluated, by dual energy X-ray absorptiometry (DEXA), the BMD of 20 young patients affected with juvenile SLE (JSLE), in order to establish the degree of osteoporosis and the influence of steroid treatment, among other clinical variables. At baseline, the mean BMD in JSLE patients was 0.978 g/cm² and in controls 1.038 g/cm² (P=0.31). At 1 year (time 2), this value became 0.947 g/cm² in JSLE children; the mean individual difference was 0.28 g/cm² (3.4%). Only in those patients aged 19–25 years BMD was significantly lower than in controls, both at baseline and at time 2. Considering the steroid treatment, no significant difference between the two groups was found either at baseline or at time 2; however, the mean yearly BMD loss in the steroid patients was 0.031 g/cm² (3.5%) vs. 0.005 g/cm² (0.5%) in those who had not taken steroids. A significantly inverse correlation between BMD and the cumulative dosage of corticosteroids has been detected. BMD produced a significantly inverse correlation to the cumulative dosage of corticosteroids; no significant correlation has been found between BMD and disease activity or duration. Received: 23 September 1997 / Accepted: 28 May 1998     

Interest of a Prescreening Questionnaire to Reduce the Cost of Bone Densitometry

Bone mineral density (BMD) measurement is widely recognized as the best single tool to identify patients with a high lifetime risk of developing an osteoporosis-related fracture. However, the cost/benefit value of screening the whole population has been repeatedly challenged and demonstrated to be rather poor. In many countries, BMD scan is not or no longer reimbursed because of lack of validated criteria to identify patients who should benefit from this procedure. Based on the proposals of a nationwide expert panel, a simple questionnaire identifying historical, clinical and behavioral risk factors for osteoporosis was developed. The aim of this study was to assess the diagnostic accuracy of the proposed criteria; to determine the extent to which this questionnaire could be useful for optimizing the use of densitometry tests; and, more specifically, to estimate the diagnostic costs per osteoporotic or osteopenic patient detected. For this purpose, we applied the questionnaire to 3998 consecutive individuals at least 20 years old, of both genders, either consulting spontaneously or referred for a BMD measurement to an outpatient osteoporosis center. BMD was measured by dual-energy X-ray absorptiometry (DXA) at the lumbar spine and at the hip (both total hip and femoral neck). Diagnostic accuracies were evaluated through measures of sensitivity, specificity, and positive and negative predictive values. After determining a benchmark value for age, different strategies were compared in order to identify the most cost-effective one in terms of cost per patient detected. According to the WHO operational definition of osteoporosis (T-score <–2.5), 31% of the subjects were classified as osteoporotic at one or more of the measured sites. If only patients with at least one of the proposed risk factors had been referred for scans, 33.3% of the BMD measurements would have been avoided. Among those, less than 5% were missclassified as they did have osteoporosis at the total hip and up to 23% at one or more of the considered sites. On the other hand, of the subjects who would be recommended for a densitometry test, only a small fraction were identified correctly (the positive predictive values varied from 11.3% at the total hip to 34.8% at any site). In this first setting, the suggested criteria seem useful chiefly for excluding subjects who do not need a DXA scan rather than selecting osteoporotic patients. When applied only to patients aged 61 years or more, the positive predictive values rose to 15.1% (total hip) and 42.9% (any site), whereas the corresponding negative predictive values were set at 93% and 68.6%. In comparison, with a mass screening scenario the estimated diagnostic costs (costs associated with the DXA procedure) per osteoporotic patient detected at any of the considered sites would be reduced by more than 9% (59.4 instead of 65.3 Euros) if the suggested indications are taken into account for prescreening patients. And when the questionnaire is applied only to women over the age of 60 years these costs would be further reduced to 50.6 Euros, representing a 23% decrease. Then, a prescreening strategy based on these indications concomitantly with an age-selective criterion could represent a promising way toward a more rational use of BMD measurement. Received: 12 April 2001 / Accepted: 29 November 2001     

A television scanning system for the measurement of the spatial variation of micro-density in bone sections

The problems encountered in the determination of the spatial distribution of bone density on a microscopic scale are discussed. A critical appraisal is presented of the practical problems encountered when specimen plane, or source plane, scanning microdensitometers are used to assess bone mineral density distributions as represented by microradiographs of thin bone sections. An image plane television scanning system is presented as the best solution with results to support its selection.     

Determination of human cone pigment density difference spectra in spatially resolved regions of the fovea

A new method was developed to measure spectrally and spatially resolved cone pigment optical density difference in normal human subjects. Using digitized television images of human retinas scanned before and after bleaching the cone pigments with a bright light, unique high-resolution images of cone pigment density difference were produced. The spectral peak density difference within the fovea was found to be at 560 nm. These measurements demonstrate a decrease in cone pigment optical density difference with increased distance from the subject's central fixation point in the fovea. The cone pigment density difference was asymmetrically distributed in the fovea with higher amounts on the nasal side.     

On-line evaluation of systolic performance by densitometry in digital left ventriculography

The angiocardiographic evaluation of left ventricular end-diastolic (LVEDV) and end-systolic (LVESV) volumes and ejection fraction (EF) is routinely performed by the area-length method (ALM) but may lead to erroneous results. Digital imaging in real time allows densitometric procedures of determining left ventricular (LV) performance to be applied alternatively. In this study, we present densitometric algorithms for the analysis of LVEDV, LVESV, and EF from digital image data, establish accuracy and reproducibility, and determine value and limitations in comparison with ALM in single-plane 30°right anterior oblique (RAO) projection. A linear relationship between iodine depth and measured densities is mainly burdened with scatter radiation and beam hardening which reduce primary radiation and suppress iodine depth. However, facilities such as deconvolution and correction algorithms are capable of reducing these sources of error. In the present study, computer-analyzed contrast images of iodine-filled wedges and spheres showed a near-linear relationship between iodine depth between 50-100 mg/cm² and measured densities. Contrast images of heart casts and LV an-gio-grams of 54 patients were obtained with a digital image acquisition and processing system, and evaluated by two in dependent observers. The phantom study resulted in significantly (p≤0.01) better densitometric standard errors of estimate for volumes [3.3 ml densitometry (DENS) vs. 8.9 ml (ALM)] and simulated EF [4.3% (DENS) vs. 7.8% (ALM)] than ALM. The standard error of estimate for the comparison between both methods was 8.4 ml for volumes and 7.5% for EF. Densitometric volumes tended to underestimate volumes calculated by ALM. The angiographic study of patients demonstrated significant correlations between both methods (LVEDV r = 0.78, LVESV r = 0.83, total volumes: r = 0.89;EF r = 0.88). The standard errors of estimate can be ascribed to systematic, method-related errors of both DENS and ALM (LVEDV ± 28.9 ml, LVESV ± 23.4 ml, total volumes (EDV and ES V) ± 27.1 ml; EF ± 8.1 %). The intra- and interobserv-er variability, respectively, exhibited significantly smaller (p ≤0.01 and p ≤0.05, respectively) standard errors of estimate for densitometric EF [4.6% (DENS) vs. 8.5% (ALM) and 7.1% (DENS) vs. 10.3% (ALM), respectively]. Inclined but not significant differences were found for LVEDV and LVESV. In conclusion, the data presented indicate that the calculation of LV volumes and EF in digital left ventriculography may be performed accurately by densitometric calculation in single-plane 30°RAO projection. Minor underestima-tions in densitometric volume determination may be anticipated in the evaluation of LV geometry.     

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.