Prediction of renal allograft chronic rejection using a model based on contrast-enhanced ultrasonography

Abstract

Objective: To evaluate the application of contrast-enhanced ultrasonography (CEUS) for the diagnosis of renal allograft chronic rejection (CR).

Methods: A total of 104 patients who were suspected to have AR or CR were enrolled in this study (derivation group, n = 66; validation group, n = 38). Before biopsy, all patients received an ultrasound examination.

Results: In the CR group, rising time (RT) and time to peak (TTP) of medulla (RTm and TTPm, respectively) were significantly longer compared to those in the AR group. The kidney volume was significantly decreased in the CR group but was increased in the AR group. In the derivation group, age, change in kidney volume, and TTPm were identified as independent predictors by multivariate analysis. Based on the multivariate analysis results and area under receiver operating characteristic (ROC) curves (AUROCs) of individual markers, we constructed a new index as follows: P = -5.424 + 0.074 × age -9.818 × kidney volume change + 0.115 × TTPm; New Index = e^P /(1 + e^P ). The new index discriminates CR from AR and had better AUROCs than any other parameters.

Conclusion: In conclusion, the new index provides a new diagnosis model for CR.

Keywords: contrast media; diagnostic test; graft Rejection; renal transplantation; ultrasonography.

Figure 1

CEUS quantification measurement and TIC. A, The 4 regions of interest were demonstrated. Yellow circle: segmental artery; green circle: interlobar artery; purple dotted circle: medulla; purple solid circle: cortex. B, In AR and CR kidneys, the TIC was coarse, especially in the AR kidney, with apparent ups and downs. In addition, the peak of the TIC for CR was sharper than AR

Figure 2

Comparison of renal function and ultrasound features between AR and CR patients in the derivation group. A, SCr; (B) eGFR; (C) RI; (D) kidney volume change; (E) RTm; (F) TTPm; (G) New index between the AR and CR groups; (H) New index between the TCMR and ABMR groups in CR patients. Data are expressed as the mean ± SD

Figure 3

Area under ROC curves. AUROCs estimated the diagnostic performance of the new index, age, RTm, TTPm, eGFR and kidney volume change in the derivation group (A) and validation group (B)

Figure 4

Comparison of renal function and ultrasound features between AR and CR patients in the validation group. A, SCr; (B) eGFR; (C) RI; (D) Kidney volume change; (E) RTm; (F) TTPm; (G) New index between the AR and CR groups; (H) New index between the TCMR and ABMR groups in CR patients. Data are expressed as the mean ± SD