Korean J Transplant.  2022 Nov;36(Supple 1):S123. 10.4285/ATW2022.F-2408.

Quantitative ultrasound for non-invasive evaluation of rejection in renal transplantation

• Lee JY
• Kim DG
• Ahn JH
• Lee T
• Choi SO
• Han BG

• KMID: 2535639
• DOI: http://doi.org/10.4285/ATW2022.F-2408

Abstract

Background
This study aimed to investigate the predictive efficacy of shear-wave elastography, superb microvascular imaging(SMI), and contrast-enhanced ultrasound (CEUS) for allograft rejection in kidney transplant without graft dysfunction.
Methods
From January 2021 to November 2021, 72 consecutive patients who underwent both allograft biopsy and ultrasound were evaluated. Blood test results were obtained within a week of the ultrasound examination. Ultrasound examinations were performed before protocol biopsy. Resistive index (RI), tissue viscoelasticity, vascular index, and quantitative CEUS parameters were measured. The patients were divided based on biopsy results into the rejection and no rejection groups.
Results
Among the 72 patients, 21 patients had pathological characteristics of acute rejection. RI of allograft was significantly higher in the rejection group (P=0.007). There were no significant between-group differences in vascular indices of SMI, mean elasticity, and mean viscosity. Meanwhile, among the parameters obtained by time-intensity curve on CEUS, the cortical and medullary ratios of average contrast signal intensity, peak enhancement, wash-in area AUC, wash-in perfusion index, wash-out AUC, and wash-in and wash-out AUC were significantly different between the two groups (P<0.05). In the receiver operating char-acteristic curve analysis for predicting allograft rejection, the AUC was 0.853 for the combination of six CEUS parameters, RI, and blood urea nitrogen.
Conclusions
Among non-invasive quantitative ultrasound measurements, CEUS parameters are the most useful for diagnosing subclinical allograft rejection. Furthermore, the combination of CEUS parameters, RI, and blood urea nitrogen may be helpful for the early detection of renal allograft rejection.