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.     

Gates法测定肾小球滤过率的精确性及与病理对照分析

Objective To evaluate the precision of GFR using Gates method and compared with the results from renal pathological changes. Methods Twenty-seven patients whose 99Tcm-DTPA renograms had no obvious uptake phase were enrolled in Group A, and 27 patients whose 99Tcm-DTPA renograms had obvious uptake phase were enrolled in Group B. The measurement of GFR by Gates method was compared to the creatinine clearance measured and predicted by Cockroft-Gault (C-G), modification of diet in renal disease (MDRD) and SCr level. Renal pathological changes in two groups were compared using Pearson correlation and t test analysis. Results In Group A, GFR determined by Gates method did not show correlation with that estimated by C-G or 1/SCr (r = 0. 357,0. 376, both P ＞0.05), but was significantly correlated with GFR estimated by MDRD(r = 0. 440, P ＜ 0.05). In Group B, GFR determined by Gates method showed significantly correlation among GFR estimated by MDRD, C-G, and 1/SCr (r =0. 471, 0. 527,0. 452, all P ＜ 0.05). Renal tubulointerstitial damage score in Group A was higher than that in Group B (7.15±2.32, 3.70±3.06, t=4.66, P ＜0.001). Conclusions GFR determined by Gates method is less precise when 99Tcm-DTPA renogram has no obvious uptake phase than that when 99Tcm-DTPA renogram has obvious uptake phase. Renal tubulointerstitial damage is a strong indicator of no obvious uptake phase in 99Tcm-DTPA renogram.     

Gates法测定肾小球滤过率的精确性及与病理对照分析

目的 探讨Gates法测定GFR的精确性,及其与肾病理改变之间的相互关系,获得Gates法测定GFR的适用范围.方法 选取99Tcm-DTPA肾功能曲线中双肾均无明显b段（即无超滤液形成段,A组）及双肾均有明显b段（B组）肾病患者各27例,比较Gates法测定GFR与CockcroftGault（C-G）公式、肾病膳食改良试验（MDRD）方程评估GFR及SCr之间的相关性,2组间病理结果（肾小球硬化分数和肾小管间质病变分数）差异行t检验比较.结果 线性相关分析证实：A组中,Gates法测定的GFR与C-G公式、1/SCr之间无明显相关性（r=0.357,0.376,P均＞0.05）与MDRD方程估算的GFR有明显相关性（r=0.440,P＜0.05）;B组中,Gates法测定的GFR与C-G公式、MDRD方程估算的GFR及1/SCr之间有正相关性（r=0.471,0.527,0.452,P均＜0.05）.A组肾小球硬化分数与B组差异无统计学意义,分别为0.26±0.24,0.27±0.21（t=-0.146,P＞0.05）,A组肾小管间质病变分数与B组差异有统计学意义,且较B组严重,分别为7.15±2.32,3.70±3.06（t=4.663,P＜0.001）.结论 99Tcm-DTPA肾功能曲线中双肾均无明显b段时,Gates法测定GFR的精确度明显低于双肾有明显b段者;99Tcm-DTPA肾功能曲线中双肾无明显b段与肾小管间质严重病变相关.     

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.     

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.     

99mTc-DTPA测得空勤人员肾小球滤过率与血浆内皮素含量的关系

目的 观察飞行员肾小球滤过率（ＧＦＲ）特点及其与血浆内皮素（ＥＴ）含量的关系。方法 采用单丸子射计算机断层摄影术（ＳＰＥＣＴ）,用＾９９ｍ锝－二乙撑三胺五乙酸（＾９９ｍＴｃ－ＤＴＰＡ）示踪剂,与放射免疫分析法（ＲＩＡ）结合,对４６名飞行员,３０名地勤人员和３０名肾病病人（均为男性）进行ＧＦＲ和ＥＴ含量测定,并分析它们之间的。结果 飞行员ＥＴ与ＧＦＲ飞行员和地勤人员。年龄与肾总ＧＦＲ存在负相关病人Ｅ     

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.     

不同肾小球滤过率检测方法在多囊肾肾功能评价中的临床价值

目的探讨99Tcm-二亚乙基三胺五乙酸（99Tcm-DTPA）肾动态显像Gate's法及血肌酐估测法在多囊肾各时期肾小球滤过率（GFR）检测中的应用价值。方法选择2006年1月至2018年9月未行透析治疗的多囊肾患者59例。参考美国慢性肾脏病及透析的临床实践指南,依据慢性肾病（CKD）分期（1~5期）,以双血浆法测定GFR为参考标准,将多囊肾患者分为3组。A组:GFR ≥ 60 mL/（min·1.73m2）,CKD分期为1~2期,共19例;B组:60 mL/（min·1.73 m2）>GFR ≥ 30 mL/（min·1.73 m2）,CKD分期为3期,共23例;C组:GFR < 30 mL/（min·1.73 m2）,CKD分期为4~5期,共17例。将Gate's法、血肌酐估测法测定的GFR分别与双血浆法测定的结果进行配对t检验和Pearson相关分析。结果（1）血肌酐估测法测得的A、B、C 3组的GFR分别为（85.43±19.77）、（46.56±15.48）、（20.96±11.3）mL/（min·1.73 m2）,双血浆法测得的GFR分别为（80.58±16.2）、（42.66±7.63）、（18.61±7.21）mL/（min·1.73 m2）,两者间的差异均无统计学意义（t=-1.462、-1.592、-1.791,均P>0.05）,且均有很好的相关性（r=0.69、0.68、0.92,均P < 0.05）。（2）Gate's法测得的A、B、C 3组的GFR分别为（75.39±20.75）、（42.86±18.95）、（25.85±14.91）mL/（min·1.73 m2）,与双血浆法测定的GFR比较,两者在A、B组中的差异均无统计学意义（t=1.255、-0.061,均P>0.05）,且均有很好的相关性（r=0.55、0.62,均P < 0.05）;但是,两者在C组中的差异有统计学意义（t=-2.132,P < 0.05）,且无明显相关性（r=0.36,P>0.05）。结论Gate's法可很好地评估多囊肾CKD分期为1~3期的患者的肾功能GFR,但对CKD分期为4~5期的患者不适合。血肌酐估测法可有效评价多囊肾CKD各时期的肾功能GFR。     

Clearance kinetics of solutes used to measure glomerular filtration rate

Agents used to measure glomerular filtration rate (GFR) give a biexponential plasma disappearance curve on multiple peripheral venous sampling between 20 min and 4 h after intravenous injection. These two exponentials are generally regarded to represent equilibration of agent throughout the extracellular fluid (ECF) space and renal clearance, respectively. In seven subjects undergoing diagnostic arteriography, arterial and antecubital venous plasma samples were obtained up to 60 min in five and up to 120 min in two following simultaneous intravenous injection of 99Tcm-diethylene triamine pentaacetate (99Tcm-DTPA) and inulin. The count rate from 99Tcm was simultaneously recorded over the calf with a collimated scintillation probe in five subjects up to 60 min post-injection. The arterial and venous time-concentration curves were interpolated and subtracted to give a curve of the arterio-venous (A-V) concentration difference, which was then integrated. Arterial time-concentration curves display three exponentials, the first of which has the largest amplitude and disappears by about 20 min. The A-V concentration difference becomes zero at about the same time. The integral of the A-V concentration difference, which represents activity in the interstitial space of the forearm, has a time course consistent with the second compartment of a model of two compartments in series (the first being plasma) and a time course that is reciprocally similar to the first exponential of the triexponential arterial plasma curve. The curve externally recorded by scintillation probe has a shape consistent with a signal that is the composite of interstitial 99Tcm-DTPA and plasma 99Tcm-DTPA activities. The arterial plasma clearance curve of GFR agents is triexponential; the first exponential reflects equilibration of agent between plasma and the interstitial space of carcass tissue (mainly muscle and skin). The second exponential is minor compared with the first; it is not clear what it represents. The third exponential reflects renal clearance.     

肾小球滤过率的临床相关因素研究

目的 探讨肾小球滤过率（GFR）与多种临床因素的相关关系。方法 用^99Tc^m－DTPA清除率测定50例肾功能正常者和72例肾功能不全者（其中原发病为慢性肾炎者46例，其他疾病者26例）GFR，同时采血测血清肌酐（SCr）、尿素氮、尿酸、K^ 、Na^ 、Ca^2 、血红蛋白，并测心率、尿比重、24时尿蛋白定量、平均动脉压、体重指数、体表面积，记录受检者年龄、测定GFR所用核素剂量。将各组及不同原发病的GFR分别与同组的上述各临床因素进行简单相关分析，对与GFR有相关关系的上述临床因素再与GFR作多元相关分析。结果 在肾功能正常、肾功能不全组中，GFR均与SCr呈负相关（r分别为－0．449和－0．275，P均＜0．05），与其他临床因素的相关关系则各不相同。结论 在肾功能正常及不同原发病引起的肾功能不全者中，SCr是反映GFR的理想指标。     

Indexing glomerular filtration rate to suit children.

In order to be able to compare individuals of differing size, glomerular filtration rate (GFR) is conventionally indexed to body surface area (BSA). This does not, however, suit children because they naturally have a relatively high BSA simply because of their small size. The aim of the study was to identify an appropriate simple whole-body variable based on height and weight suitable for indexing GFR that would be simultaneously appropriate for both children and adults. METHODS: A database of 532 routine clinical GFR measurements, each based on 3 venous blood samples obtained between 2 and 4 h after injection of (51)Cr-ethylenediaminetetraacetic acid, was analyzed to give GFR and, using only the half-time of the slope of the clearance curve, the quotient GFR to extracellular fluid volume (ECV). BSA was obtained from the Haycock formula, which is based on height and weight raised to indices to give units of area. Both GFR and GFR/ECV were corrected for the 1-compartment assumption using previously published empiric correction formulas. ECV was obtained by dividing GFR by GFR/ECV. An equation analogous to Haycock's was derived in which the indices of height and weight were varied to give an iterative best fit to ECV instead of BSA. RESULTS: GFR, ECV, and BSA increase as functions of age until about age 13 y, corresponding to a BSA of about 1.35 m(2), which was taken as the cutoff point between children and adults. As humans grow, their ratio of height to effective radius changes as a nonlinear function of surface area. Humans must therefore change shape as they grow. Moreover, the ECV-to-weight ratio decreases as a function of body size, suggesting that humans also change body composition as they grow. The new equation, giving an iterative best fit to ECV, was ECV = weight(0.6469) x height(0.7236) x 0.02154. ECV, either measured or estimated from the new equation, corresponding to a BSA of 1.73 m(2), was 12.9 L. Expressed as values normalized to the corresponding average adult values, the new equation and the second-order polynomial fit to ECV were superimposed as they increased as functions of BSA or weight. In contrast, normalized BSA and normalized weight were respectively larger and smaller than normalized ECV in children. GFR indexed to the new equation correlated more closely with GFR indexed to ECV than did GFR indexed to BSA and, along with GFR/ECV, showed a greater fall as a function of age than did GFR/BSA. CONCLUSION: When required in absolute units rather than as a rate of turnover of ECV, GFR is appropriately indexed to indices of height and weight as defined by this new equation, which avoids disadvantages to children from indexing to BSA. This unmasks higher values of filtration function in children than have hitherto been recognized.     

A simple method for measuring severely reduced glomerular filtration rate

OBJECTIVE: The purpose of this study was to develop a simpler method to measure severely reduced glomerular filtration rate (GFR) for patients with a GFR below 30 mL/min. METHOD: The GFR was measured in 24 patients using both the 51Cr EDTA slope-intercept method (the conventional method) and 99mTc-DTPA with our proposed simpler GFRn method. RESULTS: The correlation coefficient was 0.92 between the 2 methods, with a slope of 0.97 and an intercept of 2 mL/min. CONCLUSION: Our simplified method for measuring GFR is accurate for most patients with severely reduced GFR. Errors are acceptably small in patients with severely reduced GFR when edema or dehydration are present. If extrarenal (liver) clearance is significant, however, a urine sampling method is required for an accurate GFR measurement.     

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.     

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.