双能X线评价慢性肾脏病患者营养状况的研究

目的：运用双能X线法（DEXA）探讨慢性肾脏病（CKD）患者营养不良的临床特点,评估DEXA的临床应用价值。方法：143例CKD4～5期的非透析CKD患者通过主观综合营养评估法（SGA）将分为营养良好组和营养不良组。测定人体学指标和生化营养指标,同时应用DEXA法测定所有患者全身肌肉组织及脂肪组织含量,探讨二者之间的相关性。结果：营养不良组（SGA评分≥2）的前白蛋白水平较低（P＜0．05）而c反应蛋白水平明显偏高（P＜0．01）,血清白蛋白水平无统计学差异。无论男性或女性组,营养不良患者均相对高龄（P＜0．05）,表现为更低的相对体重（P＜0．01）、体重指数（P＜0．05）和肾小球滤过率（P＜0．01）。男性营养不良组三头肌皮褶厚度（T鞋叮）、上臂周径（AC）、上臂中部肌肉周径（AMC）、LBM—DXA、FM—DXA均较营养正常组有显著性降低。女性营养不良组表现为TS耵、AC和FM—DXA的显著降低,而舢和LBM～D：认无统计学差异。DXA—LBM值与AMC之间存在显著相关性（r=0．864,P＜0．001）;DXA—FM值与聊存在显著相关性（r：0．799,P＜0．001）;Logistic回归分析显示：低FMDXA百分比、高血清C反应蛋白水平和低肾小球滤过率是营养不良的独立危险因素。结论：低DXA—FM百分比、高血清c反应蛋白水平和低肾小球滤过率对预测营养不良的发生具有较高价值。双能X线测定脂肪及肌肉组织含量与传统人体学测量指标有良好的相关性,尤其DEXA—FM百分比评价CKD患者营养状况精确度高,重复性好,可早期发现CKD患者的营养不良,值得推广。     

2型糖尿病患者双能X线骨密度测定

目的观察2型糖尿病对骨密度的影响。方法应用双能X线骨密度仪(DXA)测定110例糖尿病的患者腰椎和髋部的骨密度(BMD)，并与对照组配对比较。结果糖尿病的患者骨密度与对照组比较呈明显下降，差异有显著性。结论采用配对设计，2型糖尿病患者多部位骨密度较对照组明显下降。     

糖尿病肾病和非糖尿病肾病患者透析时机探讨

<正>糖尿病肾病导致的肾衰竭占临床肾衰竭患者病因的相当大的部分,甚至在部分一线城市是肾衰竭第一位的原因[1]。但是糖尿病肾衰竭的患者跟非糖尿病肾衰竭患者的临床特点不同,研究两者的不同特点,对临床工作决定何时进入透析有帮助,对医保政策的制定有参考意义。本研究通过调查2016年04月01日~2017年12月31日汕头大学第二附属医院肾内科和中山大学附属第六医院肾内科二科行透析治疗的慢性肾脏     

腹膜透析患者营养状况的评价

在终末期肾功能衰竭(ESRD)透析与非透析病人中营养不良普遍存在,它能导致患者高死亡率、高感染率及低康复率。由于腹膜透析(腹透)的特殊性,营养不良尤其明显。Young等对欧美6个透析中心,224例情况加以统计,营养不良发生率达40.6％,其中严重营养不良者占8％。导致腹透病人营养不良的因素有:(1)蛋白质摄入不足:其中厌食是主要原因,若透析不充分,毒素蓄积,影响食欲使蛋白质的摄入减少;其次,腹透时腹膜对糖的吸收(占总热量20％),并且腹腔中加入2升左右的透析液,使患者有饱腹感,胃纳下     

双能X线和定量CT对2型糖尿病患者骨质疏松的诊断价值分析

2型糖尿病(type 2 diabetes mellitus,T2DM)通过多种机制引起骨质疏松,定量计算机断层扫描(quantitative com-puted tomography,QCT)和双能X线吸收仪(dual energy X-ray absorptiometer,DXA)是常用的检测骨质疏松的手段.对于T...     

糖尿病肾病和非糖尿病肾病腹膜透析患者容量负荷及营养状态分析

目的分析腹膜透析治疗1年内糖尿病肾脏疾病(diabetic kidney disease,DKD)和非糖尿病肾脏疾病(non-diabetic kidney disease,NDKD)患者容量负荷及营养状态相关指标变化情况,为更好的临床管理提供理论依据。方法采用回顾性分析,收集2010年1月至2019年8月在上海中医药大学附属普陀医院肾内科接受腹膜透析(PD)治疗的116例患者(其中DKD组42例,NDKD组74例)的一般资料以及PD治疗模式、透析液浓度及剂量、24 h超滤量、24 h尿量、血压、水肿情况、服用降压药种类等临床资料,并收集PD治疗前及治疗1、3、6、12月后的肝功能、脑钠素(brain natriuretic peptide,BNP)等实验室检查指标,进行组内纵向比较及组间横向比较,明确PD治疗效果及两组间的疗效差异。结果 DKD组从透析1月起各时段PD治疗剂量均高于NDKD组(P0.05),24 h PD超滤量则无显著性差异(P0.05);但透析12月后DKD组24 h尿量少于NDKD组(P0.05),水肿发生率高于NDKD组(P0.05),血压水平及服用降压药种类无显著性差异(P0.05);PD治疗后研究人群血清白蛋白(Alb)较基线值降低(P0.05),DKD组从基线起至透析6月后Alb低于NDKD组(P0.05),透析6月后两组间Alb水平未见显著性差异(P0.05)。结论 DKD组较NDKD组在腹膜透析早期营养状态更差,透析12月后处于更高的容量负荷状态,透析1月后需要更大的PD治疗剂量,提示临床医生需根据患者体液潴留、血压和其他因素制定合理的PD方案以维持适当的血容量,保护患者残余肾功能。     

双能X线吸收机对下肢延长中新骨形成的评价

双能Ｘ线吸收机对下肢延长中新骨形成的评价一种精确，无损伤测定新骨形成数量的方法对判断骨折的愈合是很有价值的，普通Ｘ线片很不灵敏，只有新骨形成达到一定数量时才能被识别，它不能用来确定新骨形成的速度。超声波已有效地用于鉴别肢体延长过程中早期新骨的形成，它...     

应用双能X线骨密度仪探讨糖尿病性骨质疏松症的影响因素

目的探讨2型糖尿病患者骨质疏松的影响因素。方法选择2011年9月至2013年3月在内分泌科住院的男性2型糖尿病患者209例为糖尿病组,选择同期体检的健康男性103例为对照组,应用双能X线骨密度仪(DXA)进行正位腰椎(L1-L4)及左侧股骨骨密度(BMD)测定,检测糖化血红蛋白(Hb A1C)、空腹血糖(FPG)及空腹C肽(CP),并进行统计学分析。结果糖尿病组骨量减少、骨质疏松发生率分别为14.35%、13.87%,明显高于对照组(P0.05)。两组检测者随着年龄增加,骨密度均呈下降趋势,50岁以上糖尿病患者腰椎及股骨颈骨密度均明显低于同龄对照组(P0.05)。糖尿病组骨密度多因素相关性分析显示,糖尿病患者骨密度与年龄、病程、Hb A1C呈显著负相关(P0.05),而与体重指数(BMI)、空腹C肽(CP)呈显著正相关(P0.05)。结论 2型糖尿病患者骨量减少及骨质疏松发生率较健康体检者明显升高;高龄、病程长及血糖控制不良是糖尿病患者BMD降低的危险因素。     

双能X线吸收法骨密度测定

骨质疏松作为老年人的常见病之一 ,越来越受到社会各界的关注。骨密度测量是明确骨质疏松的诊断、估计骨质疏松的程度、评价骨质疏松的疗效[1 ] 的必要手段。随着骨密度测量技术的发展 ,越来越多的精确度和准确度越来越高的骨密度测量方法问世。双能Ｘ线吸收法 (ＤＸＡ)以其准确度和精确度高、辐射剂量低、扫描时间短、调节稳定等优点广泛地应用于临床[2 ] 。本文就ＤＸＡ测定方法有关内容进行综述 ,供广大临床工作者参考。ＤＸＡ的工作原理ＤＸＡ用Ｘ线管代替同位素产生独立的双能量光子 ,通过单独测量这两种能量光子的吸收情况 ,计算出骨…     

终末期糖尿病肾病患者透析方式的选择

糖尿病肾病(DN)是导致终末期肾脏病的重要病因之一。终末期DN患者可选择的透析方式包括血液透析和腹膜透析,而具体选择何种透析方式,需要综合考虑共存疾病、家庭情况、患者的独立性与积极性、耐受容量转移的能力、血管条件和/或腹部的状态、感染风险及感染史等。     

Long-term evaluation of nutritional status using dual-energy X-ray absorptiometry in chronic hemodialysis patients

BACKGROUND: Hemodialysis patients very often suffer from malnutrition with net loss of body muscle and fat stores. Since protein-calorie malnutrition has been considered to be highly associated with increased morbidity and mortality, it is important that the nutritional status is evaluated accurately and that long-term evaluation of the nutritional status is performed to obtain good outcome. PATIENTS AND METHODS: Forty-six patients (28 men and 18 women) undergoing maintenance hemodialysis were studied. Nutritional status of the patients was examined by dual-energy X-ray absorptiometry (DXA) and anthropometry measurements after a hemodialysis session and 4 years after the initial measurement. RESULTS: Percent fat, the ratio of body fat (BF) to weight, determined by DXA correlated positively with body mass index (BMI) calculated from weight and height. There was also a significant positive correlation between lean body mass (LBM) determined by DXA and arm muscle circumference (AMC) calculated using the anthropometric method. In the study period of 4 years, LBM and bone mineral content (BMC) observed at the end point were significantly lower than those at the start. In contrast, BF and %fat at the end point were significantly higher as compared with those at the initial measurement. CONCLUSION: These results indicate that DXA is a reliable method for body composition analysis in chronic hemodialysis patients. Because the detection of early alterations in body composition may provide an early indication of the development of malnutrition, serial evaluation of body composition using DXA should be valid for assessment of the nutritional status.     

Bone status assessment in preterm and term infants by dual-energy X-ray absorptiometry

We assessed the bone status of preterm and term infants by measuring their bone mineral density (BMD) by dual-energy X-ray absorptiometry (DXA). Thirty neonates weighing 699–3590 g were selected as subjects. Infants with multiple anomalies or severe chronic lung disease were excluded. Using the corrected term age (35–48 weeks), we measured their lumbar spinal BMD (L1–L4) by DXA. Alkaline phosphatase (ALP) and skeletal alkaline phosphatase (B-ALP) were measured at the same time. In addition, we compared the BMD values with growth parameters and chemical markers. The term BMD correlated significantly with the birth weight (r = .90), height (r = .85), and gestational age (r = .76). The birth weight correlated more closely with the BMD than with the weight at the time of BMD measurement. The B-ALP level showed an inverse correlation with BMD (r = −0.41). The preterm infants apparently acquired lower BMDs during intrauterine life. The inverse correlation of B-ALP with BMD may be found only in the neonatal period. The BMD measured by DXA and the B-ALP level are very useful parameters for assessing bone status in infants, including extremely low birth weight infants. Received: Aug. 21, 1997 / Accepted: Nov. 6, 1997     

Bone mineral assessment by dual-energy X-ray absorptiometry in patients with coxarthrosis

Summary Forty patients with unilateral osteoarthritis of the hip were studied with dual energy X-ray absorptiometry to quantify disuse osteopenia in their affected leg by examining the proximal femur and tibia. Bone loss was assessed as a percentage of the contralateral value which compares bone mineral density of the affected and normal sides. The percentage contralateral value in the femoral neck and Ward's triangle was 113% and 118% respectively, while that in the tibia was 75%. Bone loss in the proximal tibia of the affected leg could be of value in assessing gait since it correlates with the gait parameters on the hip rating scale. By contrast, bone mineral increase in the proximal femur and correlates only with the degree of valgus deformity of the femoral neck.

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Résumé Quarante patients atteints de coxarthrose ont été examinés par absorptiométrie radiologique à double énergie afin de mesurer l'ostéopénie du côté malade. L'étude a été essentiellement centrée sur le fémur et le tibia proximal. La perte osseuse a été évaluée quantitativement selon une valeur dite pourcentage controlatéral (% CL), qui consiste dans la comparaison entre la densité minérale osseuse du côté sain et celle du côté atteint. Pour le col du fémur et le triangle de Ward, le % CL s'établit respectivement à 113% (p<0.01) et 118% (p<0.01), et à 75% (p<0.01) pour le tibia. Le % CL du tibia proximal témoigne de la perte osseuse du côté atteint et pourrait avoir un intérêt clinique pour évaluer la marche, car il concorde avec les paramètres de celle-ci sur l'échelle de cotation de la hanche, par exemple le rapport entre claudication et distance parcourue. Par contre, le % CL du fémur proximal montre un accroissement de la densité minérale osseuse qui ne concorde qu'avec le degré de déformation du col du fémur.

     

Comparison of total-body measurements by dual-energy X-ray absorptiometry and dual-photon absorptiometry

Both dual-photon absorptiometry (DPA) using 153Gd and dual-energy x-ray absorptiometry (DEXA) can be used for measurement of bone mineral content (BMC) and bone mineral density (BMD) of the total skeleton and its seven major regions. The short-term precision (coefficient of variation, CV) of DEXA for total-body BMD using the medium (20 minute) and fast (10 minute) speeds was 0.34 and 0.68% in 5 normal subjects; the corresponding CV in 5 osteoporotic females were 0.70 and 1.04%. The CV for BMD using DPA was 0.82% in 8 normal subjects and 0.70% in 12 osteoporotic patients. The CV for regional BMD using DPA was similar to fast-speed DEXA, without significant differences (p NS); precision with medium-speed DEXA was superior to DPA, and the differences were statistically significant (p less than 0.05) for head, spine, trunk, ribs, and pelvis. Total-body measurements using both DPA and DEXA were done on 99 subjects (84 females and 15 males). Significant correlations (r = 0.98; p less than 0.001) were found between DEXA and DPA measurements of both BMC and BMD. There were also significant correlations (r = 0.94-0.98; p less than 0.001) between DEXA and DPA measurements of anatomic regions (head, trunk, spine, pelvis, ribs, arms, and legs). DPA and DEXA results for BMD of total skeleton, ribs, pelvis, and legs were similar (p NS), and statistically significant differences were found in head, spine, and arm measurements (p less than 0.01, p less than 0.01, and p less than 0.05, respectively); regression equations allowed adjustment of DEXA values in patients already measured with the earlier DPA method.     

Vertebral fracture assessment by new dual-energy X-ray absorptiometry

The aim of this study was to investigate the diagnostic performance of new dual-energy X-ray absorptiometry (DXA) technologies in the detection of vertebral fractures (VFs). Sixty-eight patients were submitted to DXA and conventional radiography (XR) on the same day. Lateral images of the spine were independently evaluated by three radiologists with different experience in skeletal imaging, in two sessions with 7 days between evaluations of the same anonymous images. The most expert physician repeated the analysis in a subsequent reading session after further 7 days. Results from expert XR evaluation were considered as gold standard. A semiquantitative approach was used to interpret images and morphometric analysis was performed when a VF was suspected. Seventy vertebrae (70/884, 7.9%) were excluded from the lesion-based analysis, as not evaluable: 11/70 (15.7%) missed by XR only, 56/70 (80.0%) missed by DXA only, 3/70 (4.3%) missed by both techniques (upper thoracic spine). Forty "true" fractures were detected (4.9% out of 814 vertebrae) in 26 patients (38.2% of the 68 studied patients). Twenty-five (62.5%) were mild fractures. DXA sensitivity and specificity were 70.0% and 98.3% on a lesion-based analysis, 73.1% and 90.5% on a patient-based analysis. Intra-observer agreement was excellent with no significant difference between the two techniques. Inter-observer agreement among the 3 observers was higher for XR (k=0.824 versus 0.720 in the detection of VFs, p=0.011). DXA accuracy was not influenced by radiologist experience; T4-L4 assessability as well as reproducibility and repeatability of the two techniques and accuracy of DXA were independent from sex, age, body mass index, grade of arthrosis. However DXA sensitivity was affected by mild VFs. Vertebral level did not affect the diagnostic performance with exception of vertebral body assessability. Latest improvements make VFs assessment by DXA competitive with traditional radiographic gold standard, providing consistent advantages and attractions. Few limitations still affect DXA performance and need to be overcome.     

Fracture stiffness in callotasis determined by dual-energy X-ray absorptiometry scanning

Assessing healing after distraction limb lengthening is essential to manage patients undergoing callotasis for leg lengthening or bone transport. Direct measurement of fracture stiffness can assess healing but the equipment may not be available. In addition, it requires removal of the fixator, which may be complicated for ring fixators. The present study investigates whether an equivalent measure of healing can be based on the mineral density pattern from dual-energy X-ray absorptiometry (DXA) scans. Nine consecutive patients undergoing callotasis were studied. Bending stiffness of the distraction segment was measured and DXA scans were performed regularly starting 6 weeks after completing distraction. In all, 23 simultaneous readings of bending stiffness and DXA scans were obtained. All density patterns showed a distinct minimum value of bone mineral density. We found a high and significant correlation between fracture bending stiffness and the square of the total mineral content at the location of minimum bone density (r2 = 0.77, P < 0.001). We conclude that DXA scans can be used reliably and effectively to determine fracture bending stiffness, valuable for determining both time of frame removal and delay in union.     

An evaluation of dual-energy X-ray absorptiometry and comparison with dual-photon absorptiometry

Dual-photon absorptiometry (DPA) is a well-established procedure for measuring bone mineral density (BMD). Recently, dual-energy X-ray absorptiomery (DXA) has become available, which has the ability to measure BMD both regionally and in the total body (TB). We have evaluated the in vivo and in vitro precision of a DXA instrument and compared it with a DPA instrument with similar software characteristics.The short-term precision of BMD measurements using DXA was assessed in 65 postmenopausal women who had duplicate scans performed, with repositioning between scans. Precision was 0.9% in the lumbar spine and 1.4% in the femoral neck.The midterm precision of DXA was compared with DPA by scanning 10 volunteers a mean of four times over 24 weeks, on both instruments. The precision of the bone mineral content (BMC) and area measurements was significantly better (P<0.05) with DXA than with DPA. Long-term in vitro precision was assessed by scanning an aluminium spine phantom over 42 weeks, and a cadaveric sample over 52 weeks, on both instruments. Precision was similar using the aluminium phantom, but was significantly improved (P<0.001) when using DXA for scanning the cadaveric sample.Highly significant correlations (allP<0.001) of BMD, BMC and area measurements were observed when 70 volunteers were scanned on both instruments. However, there was a systematic difference in BMD values between the instruments. The precision of TB composition measurements assessed in 16 volunteers, over a 16-week period, were TB BMD 0.65%, TB lean tissue 1.47%, and TB fat tissue 2.73%. The correlation between weight measured by electronic scales and TB mass as measured by DXA, which was assessed in 70 volunteers, was excellent (r=0.99,p<0.001).We conclude that DXA offers improvements in measuring BMD over DPA in terms of faster scanning times and improved resolution, resulting in better precision, with the additional advantage of the ability to measure TB composition with high precision.     

Precision and stability of dual-energy X-ray absorptiometry measurements

Summary This study was performed to determine the precision and stability of dual-energy X-ray absorptiometry (DEXA) measurements, to compare bone mineral density (BMD) of subjects measured by DEXA and radionuclide dual-photon absorptiometry (DPA), and to evaluate different absorber materials for use with an external standard. Short-term precision (% coefficient of variation, CV) was determined in 6 subjects scanned six times each with repositioning, initially and 9 months later. Mean CV was 1.04% for spine and 2.13% for femoral neck BMD; for whole-body measurements in 5 subjects, mean CV was 0.64% for BMD, 2.2% for fat, and 1.05% for lean body mass. Precision of aluminum phantom measurements made over a 9-month period was 0.89% with the phantom in 15.2 cm, 0.88% in 20.3 cm, and 1.42% in 27.9 cm of water. In 51 subjects, BMD by DEXA and DPA was correlated for the spine (r=0.98,P=0.000) and femoral neck (r=0.91,P=0.000). Spine BMD was 4.5% lower and femoral neck BMD 3.1% higher by DEXA than by DPA. An aluminum phantom was scanned repeatedly, in both water and in an oil/water (30∶70) mixture at thicknesses ranging from 15.2 through 27.9 cm. Phantom BMD was lower at 15.2 cm than at higher thicknesses of both water and oil/water (P=0.05, ANOVA). The phantom was scanned repeatedly in 15.2, 20.3, and 27.9 cm of water over a 9 month period. In 15.2 and 20.3 cm of water, phantom BMD did not vary significantly whereas in 27.9 cm of water (equivalent to a human over 30 cm thick), phantom BMD increased 2.3% (P=0.01) over the 9 months.