Predictive value of contrast‐enhanced ultrasonography for the early diagnosis of renal dysfunction after kidney transplantation: A systematic review and meta‐analysis

Objectives We aimed to evaluate the changes in renal cortical microperfusion and quantitative contrast‐enhanced ultrasonography (CEUS) parameters after kidney transplantation, and to determine the evidence‐based value of CEUS in predicting renal dysfunction. Methods The Embase, MEDLINE, Web of Science, and Cochrane Library databases were searched for relevant studies published from 2000 to 2023 on the use of CEUS to assess the renal cortical microcirculation after kidney transplantation. Subject terms and related keywords were combined, and a meta‐analysis and systematic review were performed according to the Preferred Reporting Items for Systematic reviews and Meta‐Analyses guidelines. Results The search yielded six studies involving 451 patients with moderate to high overall quality. The peak intensity (standardized mean difference [SMD]: −0.64, 95% confidence interval [CI] −1.13 to −0.15, p = 0.01) of CEUS was significantly lower in patients with renal dysfunction than in those with stable renal function. However, the time to peak (SMD: 0.28, 95% CI 0.04 to 0.52, p = 0.02) was significantly shorter in patients with renal dysfunction than in those with stable renal function. The total renal cortical microperfusion and renal cortical perfusion intensity were decreased, and the perfusion time was prolonged, in patients with renal dysfunction after kidney transplantation. Conclusion CEUS parameters can reflect real‐time changes in renal cortical microperfusion, thus providing a basis for the early diagnosis of renal dysfunction after kidney transplantation. Contrast‐enhanced ultrasonography (CEUS) is a noninvasive imaging technique used to diagnose renal cortical function after kidney transplantation. CEUS parameters that can be used to reach such a diagnosis have not been standardized. This meta‐analysis provides an evidence basis for CEUS evaluation after kidney transplantation by evaluating the changes in renal cortical microperfusion and quantitative CEUS parameters after kidney transplantation.