Application of ultrasonography elastography in chronic transplanted kidney renal insufficiency: a narrative review

Chronic renal allograft dysfunction, driven by fibrosis, remains a major challenge post-transplantation. Traditional biomarkers lack sensitivity for early detection, and biopsy involves certain risks. This review evaluates ultrasound elastography, particularly shear wave elastography (SWE), as a noninvasive tool for assessing graft fibrosis and guiding timely interventions.

A comprehensive literature search was conducted of the PubMed and China National Knowledge Infrastructure (CNKI) databases (2010-2024), including studies in English and Chinese. Keywords included "ultrasound elastography", "transplanted renal insufficiency", "postoperative monitoring of transplanted kidneys" and "two-dimensional shear wave elastography".

SWE demonstrates promise in detecting early fibrosis before functional decline, with transplanted kidneys' superficial location enhancing feasibility. Studies indicate that SWE correlates with histopathological fibrosis (Banff scores) and graft dysfunction (e.g., estimated glomerular filtration rate decline and proteinuria). However, technical challenges include anatomical anisotropy, perfusion variability, and viscoelastic complexity, leading to inconsistent results. Innovations such as shear wave dispersion slope analysis improve rejection prediction, while high-frequency SWE enhances the assessment of chronic lesions. Among the notable clinical applications of SWE include its potential to reduce reliance on biopsy and the prediction of graft viability.

SWE is potentially transformative for noninvasive graft monitoring, enabling early intervention and personalized care. Standardization of protocols and multicenter validation are critical to addressing the current limitations. Future research should focus on establishing normative stiffness values, refining viscoelastic models, and validating prognostic utility to influence clinical guidelines and policy frameworks for transplant management.