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Copyright ©The Author(s) 2020. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Radiol. Aug 28, 2020; 12(8): 156-171
Published online Aug 28, 2020. doi: 10.4329/wjr.v12.i8.156
Role for contrast-enhanced ultrasound in assessing complications after kidney transplant
Giuseppe Como, Jacopo Da Re, Gian Luigi Adani, Chiara Zuiani, Rossano Girometti
Giuseppe Como, Institute of Radiology, University Hospital S. Maria della Misericordia, Udine 33100, Italy
Jacopo Da Re, Chiara Zuiani, Rossano Girometti, Institute of Radiology, Department of Medicine, University of Udine, University Hospital S. Maria della Misericordia, Udine 33100, Italy
Gian Luigi Adani, Department of Medicine, General Surgery and Transplantation, University Hospital S. Maria della Misericordia, Udine 33100, Italy
Author contributions: Girometti R designed the review and its content; Como G and Da Re J wrote the manuscript; Girometti R and Adani GL edited the manuscript; Da Re J, Zuiani C and Girometti R performed literature research; Como G and Zuiani C obtained and elaborated the images; Adani GL edited the figures and figures captions; all the Authors revised the manuscript.
Conflict-of-interest statement: Authors declare no conflict of interests for this article.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Corresponding author: Rossano Girometti, MD, Associate Professor, Institute of Radiology, Department of Medicine, University of Udine, University Hospital S. Maria della Misericordia, 15, p.le Santa Maria della Misericordia, Udine 33100, Italy. rgirometti@sirm.org
Received: March 28, 2020
Peer-review started: March 28, 2020
First decision: April 22, 2020
Revised: April 30, 2020
Accepted: July 18, 2020
Article in press: July 18, 2020
Published online: August 28, 2020
Processing time: 148 Days and 24 Hours
Abstract

Kidney transplantation (KT) is an effective treatment for end-stage renal disease. Despite their rate has reduced over time, post-transplant complications still represent a major clinical problem because of the associated risk of graft failure and loss. Thus, post-KT complications should be diagnosed and treated promptly. Imaging plays a pivotal role in this setting. Grayscale ultrasound (US) with color Doppler analysis is the first-line imaging modality for assessing complications, although many findings lack specificity. When performed by experienced operators, contrast-enhanced US (CEUS) has been advocated as a safe and fast tool to improve the accuracy of US. Also, when performing CEUS there is potentially no need for further imaging, such as contrast-enhanced computed tomography or magnetic resonance imaging, which are often contraindicated in recipients with impaired renal function. This technique is also portable to patients’ bedside, thus having the potential of maximizing the cost-effectiveness of the whole diagnostic process. Finally, the use of blood-pool contrast agents allows translating information on graft microvasculature into time-intensity curves, and in turn quantitative perfusion indexes. Quantitative analysis is under evaluation as a tool to diagnose rejection or other causes of graft dysfunction. In this paper, we review and illustrate the indications to CEUS in the post-KT setting, as well as the main CEUS findings that can help establishing the diagnosis and planning the most adequate treatment.

Keywords: Contrast-enhanced ultrasound; Kidney transplant; Post-renal transplant complications; Graft function; Ultrasound contrast agents

Core tip: Contrast-enhanced ultrasound (CEUS) allows an accurate assessment of renal graft status. When the examination is performed by experienced operators, CEUS is a fast and safe technique that can complement ultrasound even at patients’ bedside. This can maximize the cost-effectiveness and speed of the diagnostic process in patients in whom computed tomography or magnetic resonance imaging are contraindicated due to impaired renal function. CEUS is able to exploit main vascular, urological, and parenchymal complications, improving the diagnostic performance of grayscale ultrasound and color Doppler examination.