Validation of Renal Function using Multiphasic Ratios between Renal Cortex and Medulla in Kidney Recipients

ABSTRACT

OBJECTIVE: To verify the multiphase ratio of Computer Tomography-value between the renal cortex and renal medulla, which can be used to concisely evaluate renal function in kidney recipients. METHODS: Fifty-eight kidney recipients were retrospectively enrolled and divided into the Normal group(eGFR≥90 mL/min/1.73m2) and Abnormal group(eGFR<90 mL/min/1.73m2) according to Chronicle Kidney Disease Epidemiology Collaboration (eGFR(CKD-EPI)) and the Modular of Diet in Renal Disease (eGFR(MDRD)) formulas respectively. The multiphasic ratios between the renal cortex and medulla in the arterial phase and venous phase were noted as A(RatioC/M) and V(RatioC/M), and the difference between those two was recorded as D(RatioC/M). Correlation/regression analysis, student t-test, and ROC curves analysis were used to test the ability of multiphasic ratios to assess renal function. RESULTS: Both A(RatioC/M) and V(RatioC/M) were moderately correlated with eGFR(CKD-EPI) (Y =20.41*X + 28.20, r=0.40 (95%Cl, 0.13-0.58), P<0.01; Y =-16.57*X + 109.8, r=-0.29 (95%Cl, -0.51--0.04), P=0.03) and eGFR(MDRD) (Y =23.72*X + 23.52, r=0.38 (95%Cl, 0.13-0.58), P<0.01; Y =-19.88*X + 119.5, r=-0.30 (95%Cl, -0.52--0.05), P=0.02). However, D(RatioC/M) was strongly positive correlated with eGFR(CKD-EPI) (Y = 30.95*X + 60.71, r=0.61 (95%Cl,0.42-0.75), P<0.001) and eGFR(MDRD) (Y = 36.47*X + 61.01, r=0.62 (95%Cl, 0.44-0.76), P<0.001), respectively, and both regression lines were not significant different (slope P=0.496, intercept P=0.378). The differences in D(RatioC/M) between the two groups were significant (all P<0.05). The ROC curve analysis provided the cutoff values of D(RatioC/M) for assessing eGFR (AUC0.863 and AUC0.822, all P<0.001). CONCLUSION: The D(RatioC/M) can be used to assess renal function for kidney recipients.