The Value Of ^99mTc-DMSA Static Renal Imaging In Calibration Of GFR By Gates Method And The Relationship Between Single Kidney Volume And Its Corresponding GFR

Objective:The purpose of this study was to investigate the effect of renal ROI and renal depth on the determination of single kidney GFR in infants with congenital hydrophrosis in^99mTc-DMSA static renal imaging calibrated renal dynamic imaging and the relationship between single kidney volume and corresponding GFR in infants with congenital hydrophrosis measured by ^99mTc-DMSA static renal imaging and renal ultrasound.Methods:According to the degree of hydronephrosis,38 children with congenital hydronephrosis within 12 months were divided into normal group,mild hydronephrosis group,moderate hydronephrosis group and severe hydronephrosis group.Within one week,the patients received ultrasonic examination,diuretic renal dynamic imaging and static imaging respectively,and lateral collection of both kidneys was performed after the completion of dynamic and static imaging.The kidney depth was obtained by lateral image and Tonnesen formula,and the difference of kidney depth obtained by three methods was analyzed.At the same time,a GFRsingle,d GFRsingle and ad GFRsingle measured by renal ROI,renal depth and renal area-depth corrected by renal static imaging were compared with g GFRsingle measured by conventional Gates method.The kidney depth and single kidney GFR obtained by different methods were tested for normality,and then the results of one-way analysis of variance were used.The kidney depth measured by different methods was compared by LSD method afterwards.The g GFRsingle group was regarded as the control group by Dunnett method,and all other groups were compared with it.P<0.05 was considered statistically significant.Then,the kidney length diameter,width and thickness measured by ultrasound and static renal imaging were substituted into the formula for the improvement of pediatric kidney volume:Length×width×thickness×0.674,each kidney volume was obtained,and the corresponding kidney function was calculated to obtain unit volume renal function（GFR/unit volume,ml/cm3）.Paired T-test was used for measurement data,and p<0.05 was considered statistically significant.Pearson correlation analysis was performed for kidney volume measured by ultrasound and corresponding single kidney GFR in different groups,and respective regression equations were obtained.Results:1.In the mild hydrosis group,there were differences in renal depth measured by renal dynamic imaging,static imaging and Tonnesen formula（F value:36.37,45.75,all P<0.05）,and pair comparison showed statistically significant differences（t value:3.90,3.78,18.80,7.10,11.74,19.78,all P<0.05）.In the moderate and severe hydronephrosis group,the kidney depth measured by the three methods also had similar results（F value:53.74,57.46,P<0.05;t value:4.70,3.97,12.05,15.97,12.80,15.132.90,10.28,12.56,2.70,12.98,15.17,all P<0.05）.There was no significant difference in renal depth between the two kinds of imaging in the normal group（F value:35.48,52.60,P<0.05;t value:2.02,2.15,P value:0.099,0.057）.2.a GFRsingle of all groups was smaller than g GFRsingle,but the values were similar,and there was no statistical significance in normal kidney（F value:3.13,7.34,P<0.05;T-value:-2.02,-1.58,P value:0.099,0.131）,while abnormal kidney（abnormal left kidney:F=4.81,P=0.004;t=-4.35,P<0.05;Abnormal right kidney:F=2.98,P=0.038;t=-5.91,P<0.05）and mild（F=2.95,P=0.038;t=-4.78,P=0.001）,moderate to severe（F=6.55,P<0.05;t=-3.49,P=0.003）The difference of hydronephrosis kidney was statistically significant.d GFRsingle of all groups was significantly higher than g GFRsingle,and the differences were statistically significant（t value:5.62,6.45,4.69,P<0.05）.ad GFRsingle was between a GFRsingle and d GFRsingle,and there were statistically significant differences in the values of right kidney in normal group,abnormal kidney,and both kidneys in mild and moderate hydronephrosis groups（t value:2.87,2.23,4.35,3.47,2.41,all P<0.05）.3.The left and right kidney diameters,widths and renal volumes measured by static renal imaging in normal group and mild hydrosis group were slightly larger than those obtained by renal ultrasound,while renal function per unit volume was smaller than those obtained by renal ultrasound.On the contrary,the left and right kidney diameter,width and kidney volume in the severe hydronephrosis group were slightly smaller than those obtained by renal ultrasound,while the renal function per unit volume was larger than those obtained by renal ultrasound,and there were statistical differences in the results among all groups（p<0.05）,but the trend of the results obtained by both groups was consistent.4.In static renal imaging,the minimum unit volume renal function of normal kidney was about 1.62ml/cm3（left kidney）,while in ultrasound,the maximum unit volume renal function of normal kidney was about 2.20ml/cm3（right kidney）,and the right kidney was significantly higher than the left kidney.In the normal left kidney and the left and right kidney groups with mild hydrosis,there was a high positive correlation between the two groups（normal left kidney r=0.865,mild hydrosis left kidney r=0.872,right kidney r=0.822）.There was a moderate positive correlation between normal right kidney and left and right kidney with severe hydronephrosis（normal right kidney r=0.783;Severe hydrosis:left kidney:r=0.542,right kidney:r=0.798）,and the correlation between the two was the least in the severe hydrosis group（r=0.542）.According to kidney ultrasound,kidney volume in different groups was linearly correlated with its corresponding GFR,and linear regression equations of different groups were obtained,indicating that kidney volume in different states corresponds to different kidney functions.Conclusion:1.Static imaging correction of renal hydronephrosis ROI can improve the accuracy of GFR of affected kidney,especially the renal function of children with moderate and severe congenital hydronephrosis.2.The kidney depth measured by static renal imaging lateral method is more accurate than that measured by dynamic renal imaging lateral method.3.The unit volume renal function of the normal kidney was about 1.62-2.20ml/cm³,which was significantly higher in the right kidney than in the left kidney,and the unit volume renal function of the affected kidney also decreased with the gradual aggravation of hydronephrosis.