Post-Transplant Ultrasound Findings in Pediatric Kidney Recipients: A Longitudinal Experience From the Children's...

Ultrasonography is routinely used after pediatric kidney transplantation, but the prevalence and longitudinal pattern, and prognostic value of abnormal findings are not well defined. We described the frequency and temporal trends of post-transplant ultrasound abnormalities in children and evaluated their association with graft outcomes.

We retrospectively included patients (< 18 years) who underwent kidney transplantation at Children's Medical Center Hospital between 2018 and 2024. Sonographic features (parenchymal changes, peritransplant collections, urinary tract abnormalities, and Doppler indices) were recorded within six predefined follow-up windows. We used descriptive statistics and Kaplan-Meier survival curves stratified by the presence of any abnormal ultrasound finding at each window. Analyses were performed in R (version 4.3).

Sixty-three patients (mean age 12.0 ± 3.9 years) were included. Abnormal findings were present in 43%-56% of scans across follow-up windows. Peritransplant collections (33.9%) and hematomas (24.6%) were common early findings, whereas hydronephrosis and increased echogenicity became more frequent over time. Resistive index elevation (> 0.8) was uncommon (< 3.5%). Three-year graft survival was 55.7%. Any abnormality on baseline ultrasound was associated with lower 36 month survival (40.9% vs. 73.1%, log-rank p = 0.025), while abnormalities detected at later windows were not associated with survival differences.

Abnormal ultrasound findings were common after pediatric kidney transplantation, particularly in the early postoperative period. Baseline abnormalities were associated with poorer long-term graft survival, which may reflect perioperative complications or early allograft injury. This supports the clinical value of baseline ultrasound for early risk stratification and guiding the follow-up intensity.