Noninvasive assessment of chronic rejection in kidney transplant recipients with linear probe shear wave elastography

To compare linear and convex probe shear wave elastography (SWE) for the diagnosis of chronic rejection in renal transplant recipients.

In this prospective study, 84 patients (42 with stable and 42 with unstable graft function) underwent SWE examinations using linear and convex probes. Elasticity values, resistive index (RI), and laboratory parameters (creatinine, eGFR, and proteinuria) were analyzed. Chronic rejection was confirmed by biopsy in patients with unstable graft function.

Linear probe SWE values were significantly higher in patients with rejection than in those without rejection (15.91 vs. 12.3 kPa, p < 0.05). A cutoff value of 15.45 kPa predicted rejection with 66.7% sensitivity and 80% specificity (AUC: 0.76). Convex probe SWE showed no diagnostic utility. Linear SWE values correlated with elevated creatinine levels (p < 0.05), increased proteinuria (p < 0.05), and reduced eGFR (r = -0.436). RI values were not predictive.

Linear probe SWE provides superior performance compared with convex probe SWE in detecting chronic rejection, representing a potential noninvasive tool to support biopsy decisions and monitor fibrosis.