慢性肾功能不全患者高血压与肾小球滤过率及临床危险因素的关系

笔者测定了本院近年收治的102例慢性肾功能不全(CRI)患者的肾小球滤过率(GFR)，应用相关分析和非条件Logistic逐步回归分析，对可能影响CRI患者高血压发生发展的GFR和部分临床危险因素进行了分析，现报道如下。     

Gate's法测定肾小球滤过率及其影响因素

肾小球滤过率(GFR)是评估肾脏功能的重要指标,与其他测定方法相比,核医学肾动态显像Gate's法具有使用简便、结果准确的特点.影响该法检测结果的因素包括肾脏放射性计数、感兴趣区的勾画、肾脏深度等多种因素.     

Gate's法测定肾小球滤过率及其影响因素

肾小球滤过率(GFR)是评估肾脏功能的重要指标,与其他测定方法相比,核医学肾动态显像Gate's法具有使用简便、结果准确的特点.影响该法检测结果的因素包括肾脏放射性计数、感兴趣区的勾画、肾脏深度等多种因素.     

99Tcm-DTPA肾动态显像测定肾小球滤过率的影响因素分析

肾小球滤过率(GFR)是反映肾功能的重要指标,利用99Tcm-二亚乙基三胺五乙酸(99Tcm-DTPA)进行肾动态显像检测GFR是目前临床最常用的方法,但测量过程中的一些可变因素和操作细节,如血浆蛋白结合、肾脏和本底感兴趣区勾画、肾脏深度、患者年龄及自身肾功能、患者准备情况和操作技术等,都可能对GFR的检测产生影响。该...     

肾小球滤过率的标准化参数

GFR的标准化对非肿瘤患者,特别是肾供体较为重要.目前研究较多的GFR标准化参数有:体表面积(BSA)、细胞外液容积(ECV)和瘦体质量(LBM).BSA的准确测定较为困难,且儿童和肥胖者的标准化效能较差;ECV特别适用于健康儿童的标准化,但肾功能受损患者的临床应用价值明显减低;LBM兼具定量准确、适用范围广等优点,现有研究表明其比BSA和ECV更适用于GFR的标准化,但其影响因素尚待进一步深入研究.     

瘦体质量和体表面积校正肾小球滤过率的比较研究

目的:分析瘦体质量(lean body mass,LBM)是否较体表面积(body surface area,BSA)更适用于肾小球滤过率(glomerular filtration rate,GFR)的校正。方法:①将239例患者分为肾功能正常组(第1组)、轻度受损组(第2组)、中度受损组(第3组)和重度受损组(第4组),比较全部患者及每组患者的Gate’s法GFR(gGFR)与血浆法GFR(pGFR)的相关性,并分析线性回归方程意义。②将239例患者按照体质量指数分为超重组、正常组和过轻组,对比超重组和正常组、过轻组和正常组的pGFRlbm,分析体质量因素是否对LBM校正后的pGFR有影响。结果:①LBM校正后pGFR和gGFR的相关系数最高(P0.05);②全部患者、第1组~第4组LBM校正后较BSA校正后和未经校正后的截距更接近0,斜率更接近1,R2值最高;③pGFRlbm超重组和pGFRlbm正常组;pGFRlbm过轻组和pGFRlbm正常组差异均无统计学意义,故尚不能认为体质量会影响pGFRlbm,造成对pGFRlbm的高估或低估。结论:LBM较BSA能更好地校正GFR,是提高gGFR及pGFR相关性的很好选择。     

兴趣区设置对Gates法测定肾小球滤过率的影响

目的:探讨肾脏及本底兴趣区ROI的勾画方式对Gates法测定肾小球滤过率(GFR)的影响.方法:对41例患者行肾动态显像,并按不同ROI勾画法计算GFR.改变本底ROI位置、大小、本底与肾脏ROI距离及肾脏ROI大小、局部偏离,观察GFR变化;将各GFR与标准Gates法GFR比较,观察结果偏离程度及导致结果偏离的因素.结果:①logistic多因素分析表明,本底ROI位置、大小、本底与肾脏ROI间距离以及"肾脏ROI大小、局部偏离"均是影响GFR的重要因素(χ2分别为250.9,73.9,53.5,215.8,P=0.000);②本底位于肾脏正下方较大范围内或肾脏ROI在外下方局部外偏时GFR与标准Gates法十分接近;本底ROI、肾脏ROI的其它各种改变均可对GFR产生较大程度的影响.结论:①Gates法GFR测定时,ROI勾画须注意多种影响因素的作用.②本底ROI设置于肾脏正下方(20～160)象素大小、(0～16)象素距离范围内可减少本底大小、距离对GFR影响.     

慢性肾脏病患者肾小球滤过率经验公式比较

目的比较肾脏疾病饮食改良研究方程式(MDRD)、新慢性肾脏疾病流行病学合作研究方程式(CKD-EPI)以及胱抑素C(Cys C)估算公式(eGFR-Cys)对慢性肾脏病(CKD)患者肾小球滤过率(GFR)的预测性能。方法测定93例CKD患者的99mTc-二乙烯三胺戊乙酸(DTPA)血浆清除率(rGFR)作为GFR金标准,另用MDRD、CKD-EPI和eGFR-Cys公式分别计算GFR估测值(eGFR),并将rGFR与3种公式计算的eGFR进行比较。结果相对于rGFR,CKD-EPI公式偏倚为-3.4±10.7ml/(min·1.73m2),eGFR-Cys公式为-4.8±11.9ml/(min·1.73m2),MDRD公式为-5.4±10.4ml/(min·1.73m2),三者间差异均无统计学意义。对于rGFR测定值30%误差范围内GFR估测值的百分率,CKD-EPI公式e、GFR-Cys公式、MDRD公式分别为74.2%7、2.0%和64.5%,差异无统计学意义。当rGFR>60ml/(min·1.73m2)时,CKD-EPI公式30%准确度(75.7%±5.1%)明显高于MDRD公式(54.1%±7.7%,P<0.05)。以放射性核素法的GFR作为标准,以rGFR≤60ml/(min·1.73m2)作为GFR受损标准,进行3种eGFR诊断GFR受损性能的受试者工作特征(ROC)曲线分析,MDRD eGFR的ROC曲线下面积为0.862,CKD-EPI为0.863,eGFR-Cys为0.877,3个曲线下面积的差异无统计学意义。结论 3个公式对GFR的估算能力基本相似。CKD-EPI公式和eGFR-Cys公式是否可以取代MDRD公式尚需进一步研究。     

肾小球滤过率评估方程在亲属肾移植供者评估中的适用性比较

目的以99mTc-DTPA血浆清除率为标准,对24 h内生肌酐清除率(Ccr)、Cockcroft-Gault(CG)方程和简化MDRD方程进行比较,评价三种方程在评估亲属肾移植供者肾功能中的应用价值。方法选择2004—2010年在我院进行评估的40例亲属肾移植供者,所有患者同步检测99mTc-GFR、血、尿肌酐等,将Ccr、C-G方程和简化MDRD方程估算的肾小球滤过率(GFR)用体表面积(BSA)标准化,与BSA标准化的99mTc-DTPA测得的GFR(99m Tc-GFR)进行比较。结果 Ccr、MDRD-GFR、CG-GFR与99mTc-GFR相关系数r分别为:0.74、0.81、0.86;三种方程的GFR估算值与99mTc-GFR差异均有显著统计学意义(P<0.01)。结论三种方程的GFR估算值与99mTc-GFR均有较好的相关性,其中以C-G方程最好,其次为简化MDRD方程,Ccr最低,但三种方程估算值与99mTc-GFR测定值差异均存在显著统计学意义。C-G方程较适合应用于亲属肾移植供者肾功能的初步评价。     

99Tcm-DTPA法肾小球滤过率在肾癌患者术前肾功能评价中的临床意义

目的 探讨99Tcm-DTPA法肾小球滤过率(GFR)在肾细胞癌(RCC)患者术前肾功能评价中的临床意义.方法　 99例RCC患者,其中行根治性肾切除术(RN)者89例,行保留肾手术(NSS)者10例.术前行99Tcm-二亚乙基三胺五乙酸(99Tcm-DTPA)显像测定GFR.比较RCC患者和对照组(正常供肾者)的GF...     

Measurement of glomerular filtration rate with 99mTc-DTPA: A comparison of gamma camera methods

A comparison has been made between three gamma camera methods for estimation of glomerular filtration rate (GFR) using ^99mTc-DTPA in a group of 27 patients with widely different renal function. Plasma clearance of ^99mTc-DTPA by multiple blood sampling was used as the reference. Percentage uptake of chelate in the bladder and kidneys at 20 min after injection gave the lowest standard error of 8.0 ml/min. Techniques using early uptake of isotope in the kidneys at 2 min after injection gave less accurate estimates. Correction for the vascular activity in the renal region of interest improved the results for the 2 min uptake technique. Gamma camera techniques provide rapid estimates of GFR which are less accurate than those obtained by plasma clearance of labelled chelate.     

Normalisation of glomerular filtration rate measurements

The result of a glomerular filtration rate (GFR) measurement on a particular patient is of limited use to the referring physician since normal GFR values vary widely with the patient's age and build, etc. To overcome this problem, it is usual to normalise the measured GFR by dividing it by the patient's surface area and multiplying the result by the surface area of a standard man. This transforms the measurement onto a scale which applies to all patients, young and old, large and small, where normal values fall within a well-defined range and where the degree of renal impairment can be quantified. We have examined the generally accepted surface area (SA) and the less well-known extracellular volume (ECV) normalisation methods of GFR measurements in a series of 110 patients. The results show that both methods produce essentially the same result; however, ECV normalisation is theoretically more correct, can be found directly without the patient's ECV being measured and does not require the use of empirical formulae. Mathematical justification for ECV normalisation is presented, and a proposed distribution pattern for the normalised measurement is introduced. A simple mathematical model shows that accurate GFR measurements can be made in the presence of an enlarged ECV, but normalisation of these will produce misleading low values.     

Estimation of glomerular filtration rate using 99mTc-DTPA and the gamma camera

Two methods of glomerular filtration rate estimation have been evaluated, based on the intravenous administration of ^99mTc-DTPA and the measurement of renal time activity curves by means of a computer linked gamma camera. A single 20 min plasma sample was also required. These methods were designed to minimize the component of error arising from decay statistics. One method was based on using a constant fraction of the cardiac activity in lieu of a perirenal region of interest for the background correction, the other was based on deconvolution by a constrained least squares technique. The first method, based on modifying the background correction, led to poor results (residual standard deviation 18.9 ml/min when compared with the plasma clearance method). The second method, based on constrained least squares deconvolution, worked as well as previously reported methods (residual standard deviation 14.5 ml/min) and appears suitable for clinical use.     

亲属活体肾供者肾小球滤过率与年龄的相关性及其临床意义

目的 探讨亲属活体肾供者肾小球滤过率(GFR)与年龄的相关性及其临床意义,为活体肾供者的选择提供客观的依据.方法161名亲属活体肾供者按年龄分为4组:第1组20～29岁(n=52),第2组30～39岁(n=44),第3组40～49岁(n=38),第4组≥50岁(n=27);同时以55岁为界,分为老年供肾组(＞55岁,n=24)和中青年供肾组(≤55岁,n=137).利用99Tcm-二亚乙基三胺五乙酸肾动态显像法定量测量供肾者GFR,对比分析不同年龄组间GFR的特性.结果 亲属活体供肾者双肾GFR为(89.55±12.87)ml·min-1·(1.73 m2)-1,不同年龄组(1～4组)GFR分别为:(88.27±12.29)ml·min-1·(1.73 m2)-1、(91.85±14.51)ml·min-1·(1.73 m2)-1、(89.25±11.26)ml·min-1·(1.73 m2)-1和(88.24±13.20)ml·min-1·(1.73 m2)-1,各组间GFR差异无统计学意义(F=2.09,P=0.10);老年供肾组与中青年供肾组GFR分别为(88.57±13.14)ml·min-1·(1.73 m2)-、(89.44±10.34)ml·min-1·(1.73 m2)-1,两组间GFR差异无统计学意义(F=1.31,P=0.25).经相关性分析,亲属供肾者GFR与年龄变化无明显相关性(r=-0.033,P=0.69).活体肾移植后供肾者均未发生严重并发症,血清肌酐、血清尿素氮均于短期内恢复正常水平,肝肾功能均正常.结论 亲属活体肾供者GFR与年龄变化无明显相关性,对于指导活体供体的选择有重要意义.     

单血浆法与双血浆法99Tcm-DTPA血浆清除率的比较

目的在慢性肾脏病(CKD)不同分期比较体表面积标准化单血浆法与双血浆法99Tcm-DTPA血浆清除率(sGFR和tGFR)测定肾小球滤过率(GFR)的可靠性.方法入选患者男107例,女83例,平均年龄(50.3±4.9)岁.分别用单血浆法和双血浆法测定CKD患者99Tcm-DTPA血浆清除率,在CKD不同分期比较sGFR和tGFR的相关性和偏离程度,并建立直线回归方程.结果当tGFR≥30 ml·min-1·(1.73 m2)-1时,sGFR与tGFR的平均绝对偏差百分数显著小于tGFR＜30 ml·mia-1·(1.73 m2)-1时(P＜0.001),相关系数大于后一组;可建立直线回归方程tGFR=-3.552+1.147×sGFR(r=0.973,P＜0.001).结论当tGFR＜30 ml·min-1·(1.73m2)-1时,sGFR显著偏离tGFR;当tGFR≥30ml·min-1·(1.73 m2)-1时,sGFR与tGFR显著相关,可用sGFR估计tGFR.     

肾脏常规皮质髓质CT平扫及增强扫描与肾功能的相关性研究

目的 探讨肾脏常规皮质、髓质CT平扫与增强扫描与肾小球滤过率(GFR)的关系.方法 回顾性分析35例单侧肾后性梗阻性肾积水患者16层螺旋CT平扫与增强皮质期影像.以SPECT的GFR为参考标准,将35例患者按照肾功能结果分为4组:正常组,轻、中、重度肾功能损害组.测量计算患肾肾皮、髓质增强程度及各项比值.采用单因素方差分析比较上述指标的差异,采用Pearson法与GFR进行相关性分析.结果 肾功能正常组及轻、中、重度受损组患肾肾皮质增强程度(CT皮增-CT皮平)分别为(154.98±28.70)、(122.67±39.32)、(81.30±32.94)和(57.60±23.49)HU、增强后患侧与健侧皮质的CT值比值(CT患皮/CT健皮)分别为0.97±0.09、0.79±0.18、0.64±0.24和0.51±0.13、患侧及健侧髓质的CT值比值(CT患髓/CT健髓)分别为0.98±0.26、0.89±0.18、0.86±0.31和0.75±0.28、患侧皮髓质CT值比值(CT患皮/CT患髓)分别为2.76±0.35、2.35±0.79、1.83±0.68和1.73±0.28、患侧皮髓质CT值比值与健侧皮髓质CT值比值之比[(CT患皮/CT患髓)/(CT健皮/CT健髓)]分别为1.00±0.28、0.89±0.34、0.75±0.17和0.69±0.14,差异有统计学意义(P<0.05).肾皮质CT值增强程度与GFR呈高度正相关(r=0.887,P<0.01),肾髓质CT值增强程度与GFR无相关性(r=0.203,P>0.05),患侧与健侧皮质增强CT比值与GFR呈高度正相关(r=0.872,P<0.01),患侧及健侧髓质增强CT比值与GFR呈中度正相关(r=0.504,P<0.01),患侧皮髓质增强CT值比值与GFR呈高度正相关(r=0.772,P<0.01),患侧皮髓质增强CT比值与健侧皮髓质增强CT比值之比与GFR呈中度正相关(r=0.663,P<0.01).以皮质期CT患皮/CT患髓高(≥2.60)、较高(2.20～2.59)、中(1.80～2.19)、低(<1.80)为判断肾功能正常、轻度损害、中度损害与重度损害的标准,对35例患肾功能SPECT结果对照,两种分组的符合率为80.0%.结论 GFR分级定量分析,不同GFR分组各肾皮质相关CT增强指标差异有统计学意义,且与GFR呈正相关,其中患侧皮髓质增强CT值比值适用于对单、双侧梗阻患者单肾功能进行评价,可对肾后性梗阻积水肾功能损害作出半定量诊断,相对于CT灌注简单方便,X线辐射剂量低.     

Gates法测定2型糖尿病肾病患者肾小球滤过率

目的 探讨2型糖尿病肾病患者99Tcm-DTPA GFR测定的时间影响及GFR对2型糖尿病肾功能异常早期诊断的临床意义.方法 招募健康志愿者11名,其中男6名,女5名,年龄47～79(61.45±7.90)岁;社区2型糖尿病肾病患者56例,其中男31例,女25例,年龄45～75(60.98±6.96)岁,均应用99Tcm-DTPA肾动态显像测定GFR.分别取注药后第2分钟和第3分钟图像勾画ROI,根据Gates分析方法,计算总肾及分肾GFR.利用SPSS 15.0软件对数据进行Pearson相关分析和两样本t检验.结果 2型糖尿病肾病患者的GFR与SCr[(84.90±14.38) μnol/L]呈负相关:注射99Tcm-DTPA后第2分钟双肾、左肾和右肾GFR均与SCr呈负相关(r=-0.599、-0.553和-0.529,均P＜0.001);第3分钟双肾、左肾和右肾GFR也均与SCr呈负相关(r=-0.652、-0.636和-0.470,均P≤0.001).2型糖尿病肾病患者双肾、左肾和右肾第3分钟GFR分别为(69.77±11.00)、(33.12±5.74)和(37.34±9.81) ml/min,低于健康对照组[(97.89±5.98)、(46.60±4.91)和(51.28±4.20) ml/min;t=-8.212、-7.233和-4.069,均P＜0.001].结论 建议对2型糖尿病肾病患者选择注射99Tcm-DTPA后第3分钟的放射性计数测定GFR;GFR测定对糖尿病肾病患者肾功能异常早期诊断具有重要意义.     

The kinetic basis of glomerular filtration rate measurement and new concepts of indexation to body size

As measurement of glomerular filtration rate (GFR) is now generally the responsibility of departments of nuclear medicine, it is important for nuclear medicine physicians and scientists to understand the pharmacokinetics of the indicators and radiotracers that are used, generally known as filtration markers. The single-injection, non-steady state technique is almost universally used, departments varying in how many blood samples are taken: rarely multisample clearance, which does not assume a single compartment of tracer distribution, commonly clearance based on a limited number of blood samples between 2 and 4 h after injection, which assumes a single compartment of distribution, and often a single sample at a defined time point. The volume of distribution, V _d , of a filtration marker is close to extracellular fluid volume (ECFV). GFR and ECFV are both overestimated by the assumption of a single compartment by amounts that are functions of the rate of plasma clearance, Z. Residence time, T, of tracer in its V _d is equal to V _d divided by Z. Z and T can both be measured from a multisample clearance curve, whereupon V _d is the product of Z and T. GFR is usually indexed to patient size by expressing it in relation to body surface area (BSA), which in turn is calculated from an equation based on the patients height and weight. An equation in common use was described by Haycock et al. and is BSA=0.024265×weight^0.5378×height^0.3964. An alternative indexation variable is ECFV. GFR per unit ECFV is close to the rate constant, ₃, of the terminal exponential of the plasma clearance curve. It is in fact slightly higher than this rate constant by an amount that is a function of the rate constant itself. The discrepancy between GFR/ECFV and ₃ arises from the development of a concentration gradient between interstitial fluid and plasma, which in turn produces an extrarenal veno-arterial gradient throughout the body. Indexing GFR to ECFV not only has physiological attractions (especially in children) but is technically simple because it requires measurement only of ₃ (slope-only technique). A disadvantage, however, is a lack of robustness in comparison with the conventional slope/intercept method, which measures tracer dilution as well as ₃. Nevertheless, the advantages of indexation to ECFV can still be exploited by changing the constants of an equation of the Haycock type so that the equation becomes a predictor of ECFV rather than BSA. A recently described equation is ECFV=0.02154×weight^0.6469×height^0.7236. Indexation to ECFV abolishes differences that arise between children and adults when GFR is indexed to BSA.     

Longitudinal assessment of glomerular filtration rate by gamma camera and portable external detector

Noninvasive isotope chelate methods to assess glomerular filtration rate (GFR) are less accurate than blood sampling. However, some measurement errors would be expected to be constant for an individual, and repeat estimations may be less variable. In 18 patients, estimates of GFR were obtained by 2 gamma camera techniques and a portable external detector at a mean interval of 1 year, to assess accuracy in predicting a change of GFR. Errors in these techniques were not significantly better than those predicted from two independent estimates. Most GFR measurement error for noninvasive methods appears to be random.