Correlation Evaluation Between The Renal Apparent Diffusion Coefficient And The Split Renal Filtration Function In Infants With Congenital Hydronephrosis

ObjectiveTo explore the relationship between ADC values measured from DWI and the glomerular filtration rate(GFR) of infants with congenital hydronephrosis;To explore the value of kidney ADC in evaluating the split renal function of infants congenital hydronephrosis.MethodsThirty healthy infants were examined with renal DWI on a 1.5T MR unit using b values including 500s/mm2,700s/mm2,1000s/mm2 and 1500s/mm2. The picture quality,signal intensities(SI),signal-to-noise ratio(SNR) on DWI were compared with the renal ADC value of normal parenchyma using analysis of variance(ANOVA), P＜0.05.Forty-six infants with congenital hydronephrosis were examined with DWI (b=0,700s/mm2) on a 1.5T MR unit and renal scintigraphy using 99mTc-DTPA.ADC value of the renal hilus section and slip GFR were measured,and the 46 patients were divided into four groups according to the GFR:renal insufficient compensation group, renal insufficient decompansation group, renal functiona depletion group and urinemia group. The renal ADC values between normal control group,obstruction contralateral normal renal and four groups were statistically compared by analysis of variance(ANOVA),and the dependablity between ADC and split GFR were analysed using Pearsons correlation test,.P<0.05. ResultsThere was a statistically significant difference in picture quality,SI,SNR and ADC values of DWI among the four groups at different b values.The ADC values of the normal kidneys were about 1.61±0.05×10-3 mm2/s when b equals 700s/mm2.There was a statistically significant difference between the renal ADC values of four hydronephrotic groups,and the mean ADC values of hydronephrotic groups were significantly lower than that of the normal kidneys. In hydronephrotic kidneys, there was a positive correlation between ADC values and split GFR(r=0.744).The ADC values of the obstruct kidneys were lower than that of the normal ones,and there was no correlation between ADC values and split GFR (r=0.194).ConclusionsIn our study, the optimal b values in evaluating the kidney of healthy infants is 700 s/mm2 and the mean ADC values of the normal infants'kidneys were 1.61±0.05×10-3mm2/s at b=700s/mm2.The mean ADC values of infants'congenital hydronephrotic kidneys were significantly lower than that of the normal kidneys and there was a positive correlation between ADC values and split GFR. The renal ADC values could reflect the renal filtration function of congenital hydronephrosis, and it may become a new way which is no harm to evaluate the split renal functional.MR routine sequence combine with DWI sequence can provide information of the renal functional and morphologic at the same time.