The Feasibility Study Of IVIM-DWI For Evaluating Split Renal Function In Children With CAKUT

Purpose:The aim of this study was to investigate the relationship between parameters with intravoxel incoherent motion?IVIM?model of diffusion weighted imaging?DWI?and single-nephron glomerular filtration rate?SNGFR?measured by ^99mTC-DTPA renal dynamic scintigraphy,and to further analyse the feasibility of DWI IVIM model in evaluating single kidney renal function in children with congenital abnormalities of the kidney and urinary tract?CAKUT?.Methods:34 children patients with CAKUT?74 kidneys?from Wuhan Children's Hospital who underwent ^99mTC-DTPA renal dynamic scintigraphy and renal magnetic resonance imaging?MRI?from December 2017 to December 2018 were retrospective analyzed.The patients were divided into three groups according to isotope renographic SNGFR:normal renal function group?GFR?40 mL/min,34 cases?,mild reduction group?20?GFR<40mL/min,25 cases?,and moderate-to-severe reduction group?GFR<20 mL/min,15cases?.DWI images were analyzed by IVIM model to obtain true diffusion coefficient?D?,pseudo diffusion coefficient?D^*?,and perfusion fraction?f?of each renal cortex.D,D^*and f values of renal cortex.Between different groups were compared statistically using one-way analysis of variance?ANOVA?,and Student-Neuman-Keuls?SNK?test was used for further comparisons between specific group pairs.The correlative relationship between these parameters and SNGFR was examined by bivariate Spearman correlation test.P<0.05 were considered statistically significant.Results:The normal distribution test showed that D did not completely satisfy normal distribution,but D^*and f?P>0.05?satisfied.The homogeneity test results showed that the D did not satisfy homogeneity of the variance?P<0.05?,but D^*and f satisfied.The differences among groups was compared statistically using one-way ANOVA.The F values of D,D^*and f were 3.577?P=0.033?,12.517?P<0.001?and 27.940?P<0.001?,respectively.The SNK test was used to further compare between specific group pairs.In the D,there was no significant difference among the three groups,and D did not satisfy the homogeneity of the variance.Therefore,although the result of one-way ANOVA?P<0.05?,the result was not considered statistically significant.Between specific group pairs,in the D^*,there were statistically significant differences.In the f,there was no difference between normal renal function group and mild reduction group,and significant differences were found between moderate-to-severe reduction group and the two other groups.Spearman correlation analysis revealed that there were positive correlations between SNGFR and D?r=0.350,P=0.002?,between SNGFR and D^*?r=0.687,P<0.001?,and between SNGFR and f?r=0.706,P<0.001?.Conclusion:In IVIM-DWI,D^*was most sensitive to differentiate the nomal renal function from the abnormity,which maybe use to evaluate renal dysfunction early.There is a correlation between D,D^*and f values and SNGFR,and the correlation between f and SNGFR is most significant,so f can provide more accurate information of renal function.Preliminary results imply that DWI IVIM model has the value in evaluating renal function in children with CAKUT.The combination analysis of D^*and f was promising way to accurately evaluate renal function of children with CAKUT early.