A Preliminary Study Of Real-time Shear-wave Elastography(2D-SWE) For Assessing Tissue Lesions In Chronic Allograft Nephropathy

Objective : The real-time shear-wave elastography(2D-SWE)technique was used to evaluate the correlation between tissue hardness and pathological changes of chronic allograft nephropathy(CAN).The differences of clinical parameters between patients with normal renal function and patients with renal dysfunction and their correlation with tissue hardness were compared.Methods:152 patients with allogeneic kidney transplantation treated in Xiangya Third Hospital of Central South University from January 2021 to March 2022 were randomly selected.99 patients who met the inclusion criteria were divided into normal renal function group(group A)and dysfunction group(group B)according to whether there was renal transplantation dysfunction.The size(length,width and thickness),peak systemic velocity(PSV),resistance index(RI),hardness value of cortex and medulla(SWE value)and other parameters.All the transplanted kidneys in the dysfunction group underwent diagnostic puncture biopsy.The differences of clinical parameters between the two groups were compared,the relationship between graft cortex and medulla hardness and related parameters was analyzed,and the correlation between tissue hardness and pathological Banff semi quantitative score in patients with can was evaluated.Results:(1)Compared with group A and group B,there were significant differences in SWE value of cortex and medulla,peak systolic velocity of interlobar artery and creatinine value(P < 0.001).The cortex and medulla SWE and creatinine levels in group B were significantly higher than those in group A,and the peak systolic velocity of interlobar artery was significantly lower than that in group A.There was no significant difference in age,sex composition ratio,body mass index(BMI),transplantation time,transplanted kidney size and resistance index(RI)between the two groups(P > 0.05).(2)The SWE value of cortex in group A was correlated with age,creatinine value and BMI.There was a weak negative correlation between age(r =-0.382,P < 0.05)and BMI(r =-0.427,P < 0.05),and a weak positive correlation between creatinine(r = 0.301,P < 0.05).There was a weak negative correlation between medullary SWE value and BMI in group A(r =-0.310,P < 0.05).SWE values of cortex and medulla in group B were not correlated with clinical parameters(P > 0.05).(3)Cortical stiffness was positively correlated with peritubular capillary vasculitis(r = 0.434,P = 0.007),total Banff score of acute lesions(i + t + v + g + ptc)(r = 0.464,P = 0.004),degree of interstitial fibrosis(r = 0.452,P = 0.005),arterial hyaline degeneration(r = 0.526,P= 0.001),total Banff score of chronic lesions(ci + ct + cv + cg + mm + ah)(r = 0.585,P < 0.001),Banff total score of all basic lesions(i + t + v + g+ ptc + ci + ct + cv + cg + mm + ah)(r = 0.719,P < 0.001);Medullary hardness was positively correlated with peritubular capillary vasculitis(r= 0.587,P < 0.001),total Banff score of acute lesions(r = 0.423,P =0.009),degree of interstitial fibrosis(r = 0.363,P = 0.027),intimal fiber thickening(r = 0.338,P = 0.041),arterial hyaline degeneration(r = 0.581,P < 0.001),total Banff score of chronic lesions(r = 0.499,P = 0.002),and Banff total score of all basic lesions(r = 0.621,P < 0.001);The level of creatinine was positively correlated with interstitial inflammation(r =0.356,P = 0.030)and total Banff score of acute lesions(r = 0.411,P =0.012);There was no correlation between cortical and medullary hardness and interstitial fibrosis/tubular atrophy(IFTA)grade(P > 0.05).Conclusion:(1)Compared with normal transplanted kidneys,the hardness of cortex and medulla of of dysfunctional transplanted kidney increased significantly,the peak systolic velocity of interlobar artery decreased significantly.(2)The correlation between the hardness of transplanted kidney cortex and medulla and the Banff total score of tissue-based lesions was better than that of blood creatinine.The level of blood creatinine was related to the acute pathological changes of transplanted kidney tissue.(3)The hardness of transplanted kidney cortex and medulla was correlated with a variety of tissue-based lesions,and had the best correlation with Banff total score.