Ultrasound shear wave elastography for the evaluation of renal pathological changes in adult patients

Objective: Many studies have conflicting findings in using shear wave elastography (SWE) to assess renal fibrosis. This study reviews the use of SWE to evaluate pathological changes in native kidneys and renal allo-grafts. It also tries to elucidate the confounding factors and care taken to ensure the results are consistent and reliable. Methods: The review was carried out according to the Preferred Reporting Items for SystematicReviews and Meta-Analysis guidelines. Literature search was conducted in Pubmed, Web of Science and Scopus data-base up to 23 October 2021. To evaluate risk and bias applicability, the Cochrane risk -of bias tool and GRADE was used. The review was registered under PROSPERO CRD42021265303.Results: A total of 2921 articles were identified. 104 full texts were examined and 26 studies included in system-atic review. 11 studies performed on native kidneys and 15 studies on transplanted kidney. A wide range of impact factors was found that affect the accuracy of SWE of renal fibrosis in adult patientsConclusions: Compared to point SWE, two-dimensional SWE with elastogram could enable better selection of the region of interest in kidneys, leading to reproducible results. Tracking waves were attenuated as the depth from skin to region of interest increased, therefore, SWE is not recommended for overweight or obese patients. Variable transducer forces might also affect SWE repro-ducibility, thus, training of operators to ensure consistent operator-dependent transducer forces may be helpful. Advances in knowledge: This review provides a holistic insight on the efficiency of using SWE in evaluating pathological changes in native and transplanted kidneys, thereby contributing to the knowledge of its utilisation in clinical practice.

Automated summary

This study reviews the use of shear wave elastography (SWE) in assessing renal fibrosis, highlighting the factors that affect its accuracy and reproducibility. The study suggests that two-dimensional SWE with elastogram provides better results in selecting the region of interest in kidneys compared to point SWE. However, SWE is not recommended for overweight or obese patients. Training of operators to ensure consistent transducer forces may also improve SWE reproducibility.