肾动态显像法与双血浆法测定肾小球滤过率的对比分析

目的:对肾动态显像法测定肾小球滤过率(glomerular filtration rate,GFR)与双血浆法进行比较,以评价肾动态显像法测定肾小球滤过率的可靠性.方法:原发或继发慢性肾脏病患者54例,按常规方法进行肾动态显像,采用仪器中的处理程序(Gates法)进行图像处理得到GFR;静脉注射锝-99m-二乙三胺五乙酸(99Tcm-DTPA)后2h及4 h取血,测定1 mL血浆中的放射性计数,用双血浆法计算公式求得GFR,对肾动态显像法与双血浆法测得的GFR进行相关性分析,并比较两者测得的GFR与血清尿素(urea)及肌酐(creatinine,Cr)水平的关系.结果:肾动态显像法与双血浆法测得的GFR值具有良好的相关性(r=0.8815,P＜0.01),两者的直线回归方程为,GFR(肾动态显像法)=0.661 4 GFR(双血浆法) 21.89;肾动态显像法与双血浆法测得的GFR与urea及Cr的相关性直线相近,表明二者几乎以相同的数量关系反映肾功能的变化;2例偏瘦的病人和1例偏胖的病人两种方法测得的GFR差异较大.结论:一般情况下肾动态显像法测得的GFR能够可靠地反映肾功能的变化,与双血浆法测得的GFR相符合,但对于特殊体形的患者,肾动态显像法测得的GFR可能会有较大的偏差.

Measurement of glomerular filtration rate with renal dynamic imaging:comparison with two-sample method

Objective:To compare the estimation of glomerular filtration rate(GFR)by renal dynamicimaging with that estimated by two-sample method and evaluate the reliability of measurement of GFR byrenal dynamic imaging.Methods:The study was performed in 54 patients(33 males and 21 females;aged 15 to 82 years)with primary or secondary chronic nephrosis.The patients were intravenously bolusinjected with 185 MBq/1 mL of (99)~Tc~m-DTPA 20 min after drinking 300 mL of water.Renal dynamic ima-ging was performed and the image was processed according to standard procedure(Gates' method)to ob-tain GFR.3mL of blood was withdrawn 2h and 4h postinjection,respectively,and radioactivity of 1mLplasma was measured.GFR was calculated by the formula of two-sample method.The correlation ofGFRs measured by renal dynamic imaging and by two-sample method was analyzed using regression anal-ysis.The correlations of GFRs determined by the two methods with urea and creatinine were also meas-ured.Results:The GFR measured by renal dynamic imaging was slightly lower than that measured bytwo-sample method.Excellent correlation was obtained by two methods with r=0.881 5 and P<0.01.The linear regression equation was GFR(renal dynamic imaging method)=0.661 4GFR(two-samplemethod) 21.89.The related lines of GFRs measured by the two methods with urea or creatinine weresimilar,which indicated the two methods were similar in identifying the changes in renal function.GFRsmeasured by the two methods showed good agreement for most of patients except three patients who weretoo thin or too fat.Conclusion:Generally,GFR obtained by renal dynamic imaging is reliable for identi-fying the changes in renal function and correlated well with GFR obtained by two-sample method.Butgreat error may be obtained with specific individuals,such as too thin or too fat subjects.