Shear wave elastography in transplant kidney and its correlation with renal doppler parameters and eGFR

Chronic allograft nephropathy is the most common cause of graft failure and is characterized by interstitial fibrosis and tubular atrophy, this study evaluated the role of shear-wave sonoelastography in the differentiation of stable renal allograft from allograft dysfunction & establish the correlation of parenchymal stiffness values with resistive index (RI), serum creatinine level, estimated glomerular filtration rate (eGFR).A prospective study of 40 patients who had undergone renal transplantation was conducted between October 2018 and July 2020.Patients were classified as having stable allograft and allograft dysfunction on the basis of clinical parameters practised in our institution.Receiver operating characteristic curve were drawn to obtain a cut off value with maximum sensitivity and specificity.Pearson's correlation was used to evaluate different renal parameters and their correlation with the shear wave elastography (SWE) value.In this study 27 patients had graft dysfunction and 13 had stable graft.Use of the threshold value of 8.23kPa for SWE resulted in a sensitivity of 70% and specificity of 100% for the differentiation of stable allograft from allograft dysfunction.Parenchymal stiffness showed inverse correlation with eGFR (r = -.756,P<0.001) and a direct correlation with RI (r-0.42,P = 0.003) and serum creatinine level (r = 0.76, P<0.001).SWE helps to differentiate stable allograft from allograft dysfunction.The direct correlation with RI & serum creatinine level and inverse correlation of parenchymal stiffness with eGFR show that SWE reflects functional status of the renal allograft.