Real time sonoelastographic evaluation of renal allografts in correlation with clinical prognostic parameters: comparison of linear and convex transducers according to segmental anatomy.

Abstract

Background: Renal transplantation is the treatment of choice in end-stage renal disease. Chronic allograft dysfunction is the leading cause of chronic allograft failure. Surveillance biopsy is the only reliable tool to detect early fibrosis in the allograft. There is a need for non-invasive methods for the detection of early development of renal allograft fibrosis. Aims: To analyse the reliability of sonographic elasticity index and resistive index measurements in the evaluation of renal transplant fibrosis using linear and convex transducers according to segmental anatomy. Materials and methods: Elasticity index and resistive index were measured in 28 renal transplants and correlated with clinical prognostic parameters. Donor age above 50 years old, post transplantation time over 60 months and serum creatinine level above 1.5 mg/dl were defined as poor prognostic parameters. Results: Renal transplant recipients with serum creatinine level above 1.5 mg/dl demonstrated higher mean elasticity index (p=0.006) with a convex probe and higher elasticity index in the middle segments both with a convex and a matrix linear probe (p=0.026, p=0.001). Renal transplant recipients with post-transplantation time of 60 months and more demonstrated higher resistive index values in the middle segments (p=0.016). Conclusions: Convex probe was able to detect the changes in mean stiffness better than the matrix linear probe. The measurements from subsegments might suggest that diffuse changes in stiffness can truly be detected in the middle segments or that fibrotic processes start from the middle segments of the renal transplants. Further studies correlated with histopathology are required to validate the findings.