The Evaluation of Advanced Ultrasonography Applications in The Assessment of Transplanted Kidneys

Abstract

Introduction: Living donor kidney transplantation is the preferred treatment for end-stage renal disease, offering superior long-term survival, cost-effectiveness, and enhanced quality of life. This study explores non-invasive advanced ultrasound techniques such as shear wave elastography (SWE), tomographic 3D ultrasound (3DUS), Veno-arterial index (VAI), and micro flow imaging (MFI) for post-transplant monitoring. Additionally, a systematic review and meta-analysis assess the role of contrast-enhanced ultrasound in evaluating post-transplant renal complications. Method: A prospective observational cohort study involving 165 post-graft transplant patients between 2020 and 2023. Participants were categorised into three groups based on graft function status: stable, dysfunctional, and failed. Each group comprised 55 patients. Conventional ultrasound scans, combined with advanced ultrasound applications, were performed during routine follow-up appointments. Intra- and inter-observer agreement studies were undertaken to determine the reproducibility of tomographic 3DUS and SWE. Results: Participants (58±11.4 years, 51.5% women) had an average BMI of 24.9±3.5, with predominant ethnicities being White British (15.8%) and Arab (13.9%). Most received deceased grafts (89.1%), had no cardiovascular disease (84.8%), no diabetes mellitus (80%), and hypertension (55.2%). Tomographic 3DUS outperformed 2DUS in grading transplant renal artery stenosis (AUC 0.91 vs. 0.03 and 0.008, respectively). SWE stiffness exhibited significant differences across graft statuses (P < 0.001), with strong predictive ability (AUC 0.94–0.99). VAI also varied significantly (P < 0.001) and achieved high sensitivity and specificity for transplant failure (VAI 0.64, 90% sensitivity, 94% specificity) and dysfunction/failure (VAI 0.52, 83% accuracy). MFI showed promise with a higher AUC (0.82) compared to colour Doppler (0.74). Conclusion: Advanced ultrasounds offer reliable, cost-effective, and repeatable monitoring of post-transplant graft complications. They serve as early predictors, facilitating timely management. Integrating these techniques into clinical practice can enhance patient outcomes, reduce invasiveness, and improve care for graft recipients. Ongoing research and validation are crucial for optimal clinical application.