The Value Of Dual-phase Enhanced Multi-slice Spiral CT In The Evaluation Of Renal Function In Unilateral Hydronephrosis

Objective: Multi-slice spiral CT dual-phase enhanced scanning is used to obtain indexes such as the degree of renal cortical enhancement,the width of renal pelvis separation and the thickness of renal parenchyma to explore the diagnostic value of unilateral hydronephrosis side renal function,and it is expected to provide an effective and convenient method for clinical evaluation of renal function.Methods: From August 2017 to October 2019,60 patients with unilateral hydronephrosis diagnosed by ultrasound or CT were enrolled in Changsha Central Hospital Affiliated to University of South China.All patients underwent renal CT dual-phase enhanced scanning and SPECT renal dynamic imaging.According to different renal function groups,the differences between groups were analyzed and compared.Spearman correlation analysis was conducted between the renal cortical enhancement,the width of renal pelvis separation and the thickness of parenchymal obtained by CT scan and GFR measured by renal dynamic imaging.Logistic regression analysis was used to predict the occurrence of abnormal renal function by CT related indexes.Then the value of renal function evaluation was evaluated according to themeasurement indexes corresponding to the area under ROC curve and the best cutoff value.P<0.05 was considered statistically significant.Results: The results of difference analysis among the four classifications of renal function showed that the age of severe renal function injury group was significantly older than that of normal group(P<0.05).There was no significant difference in the width of renal pelvis separation between the normal renal function group and the mildly impaired group,the mildly impaired group and the moderately impaired group,this index was statistically significant among other groups.The thickness of renal parenchyma in the affected group with moderate and severe renal impairment was smaller than that in the normal group and the mildly impaired group,and the difference was statistically significant(P<0.05).The degree of cortical enhancement in the cortical phase of the normal renal function group in the affected side is greater than that in the severely impaired group.The degree of cortical enhancement in the nephrographic phase of normal group was greater than that of the moderately and severely impaired group,and the degree of cortical enhancement in the mildly impaired group was greater than that of the severely impaired group,with the difference was statistically significant(P<0.05).There were significant differences in hydronephrosis GFR among four groups(P<0.05).There was no statistically significant difference between the four groups in the affected side position,gender and healthy side kidney index(P>0.05).Spearman correlation analysis showed that the width of the renalpelvis separation on the affected side was negatively correlated with GFR,with the correlation coefficients r=-0.722(P<0.01).While the thickness of renal parenchyma and the degree of cortical enhancement in the cortical and nephrographic phase were positively correlated with GFR,the correlation coefficients were r=0.834,0.498,and 0.685,respectively(P<0.01).According to logistic regression analysis,the width of the renal pelvis separation was a positive predictor of abnormal renal function(OR>1),and the thickness of renal parenchyma,the degree of cortical enhancement in the cortical and parenchymal phase were negative predictor of abnormal renal function(OR<1),all of which were statistically significant(P<0.05).According to the ROC curve,it can be seen that the four indicators of CT prediction of renal function have diagnostic value(P<0.05).When the width of the renal pelvis separation is more than 13.3mm,the thickness of renal parenchyma is less than 17.9mm,the degree of cortical enhancement in the cortical phase is less than 0.705,and the degree of cortical enhancement in nephrographic phase is less than 1.425,it can be judged as abnormal renal function.Conclusion : 1.MSCT measurement of renal cortical enhancement,the width of renal pelvis separation,and the thickness of renal parenchymal can be used as a semi-quantitative method for clinical evaluation of hydronephrosis and renal function,but there are certain limitations to the evaluation of mild renal impairment.2.The width of renal pelvis separation and the degree ofcortical enhancement in parenchymal phase are more valuable for judging abnormal renal function.