Observational Study
Copyright ©The Author(s) 2024. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Transplant. Mar 18, 2024; 14(1): 89255
Published online Mar 18, 2024. doi: 10.5500/wjt.v14.i1.89255
Comparison of resistive index and shear-wave elastography in the evaluation of chronic kidney allograft dysfunction
Ameet Kumar Jesrani, Syed M Faiq, Rahma Rashid, Tariq Ali Kalwar, Rehan Mohsin, Tahir Aziz, Nida Amin Khan, Muhammed Mubarak
Ameet Kumar Jesrani, Syed M Faiq, Nida Amin Khan, Department of Radiology, Sindh Institute of Urology and Transplantation, Karachi 74200, Sindh, Pakistan
Rahma Rashid, Muhammed Mubarak, Department of Pathology, Sindh Institute of Urology and Transplantation, Karachi 74200, Sindh, Pakistan
Tariq Ali Kalwar, Tahir Aziz, Department of Transplantation, Sindh Institute of Urology and Transplantation, Karachi 74200, Sindh, Pakistan
Rehan Mohsin, Department of Urology, Sindh Institute of Urology and Transplantation, Karachi 74200, Sindh, Pakistan
Author contributions: Jesrani AK, Faiq SM, Rashid R, Kalwar TA, Mohsin R, Aziz T, Khan NA, and Mubarak M, all eight authors contributed significantly and equally to the preparation of the manuscript; Jesrani AK and Kalwar TA conceived and designed the study; Jesrani AK, Kalwar TA, Khan NA, and Faiq SM performed the research; All eight participated in primary and final drafting; Mubarak M critically reviewed and finalized the draft; All read and approved the final manuscript.
Institutional review board statement: The study was reviewed and approved by the Sindh Institute of Urology and Transplantation Institutional Review Board, No. 387.
Informed consent statement: All study participants, or their legal guardian, provided informed written consent prior to study enrollment.
Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article.
Data sharing statement: The data is available with the first author of the study and can be shared on reasonable request at drmubaraksiut@yahoo.com.
STROBE statement: The authors have read the STROBE Statement—checklist of items, and the manuscript was prepared and revised according to the STROBE Statement—checklist of items.
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: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Muhammed Mubarak, MD, Professor, Department of Pathology, Sindh Institute of Urology and Transplantation, Chand Bibi Road, DFMC, Karachi 74200, Sindh, Pakistan. drmubaraksiut@yahoo.com
Received: October 25, 2023
Peer-review started: October 25, 2023
First decision: January 12, 2024
Revised: January 18, 2024
Accepted: February 27, 2024
Article in press: February 27, 2024
Published online: March 18, 2024
Abstract
BACKGROUND

Detection of early chronic changes in the kidney allograft is important for timely intervention and long-term survival. Conventional and novel ultrasound-based investigations are being increasingly used for this purpose with variable results.

AIM

To compare the diagnostic performance of resistive index (RI) and shear wave elastography (SWE) in the diagnosis of chronic fibrosing changes of kidney allograft with histopathological results.

METHODS

This is a cross-sectional and comparative study. A total of 154 kidney transplant recipients were included in this study, which was conducted at the Departments of Transplantation and Radiology, Sindh Institute of Urology and Transplantation, Karachi, Pakistan, from August 2022 to February 2023. All consecutive patients with increased serum creatinine levels and reduced glomerular filtration rate (GFR) after three months of transplantation were enrolled in this study. SWE and RI were performed and the findings of these were evaluated against the kidney allograft biopsy results to determine their diagnostic utility.

RESULTS

The mean age of all patients was 35.32 ± 11.08 years. Among these, 126 (81.8%) were males and 28 (18.2%) were females. The mean serum creatinine in all patients was 2.86 ± 1.68 mg/dL and the mean estimated GFR was 35.38 ± 17.27 mL/min/1.73 m2. Kidney allograft biopsy results showed chronic changes in 55 (37.66%) biopsies. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of SWE for the detection of chronic allograft damage were 93.10%, 96.87%%, 94.73%, and 95.87%, respectively, and the diagnostic accuracy was 95.45%. For RI, the sensitivity, specificity, PPV, and NPV were 76.92%, 83.33%, 70.17%, and 87.62%, respectively, and the diagnostic accuracy was 81.16%.

CONCLUSION

The results from this study show that SWE is more sensitive and specific as compared to RI in the evaluation of chronic allograft damage. It can be of great help during the routine follow-up of kidney transplant recipients for screening and early detection of chronic changes and selecting patients for allograft biopsy.

Keywords: Shear wave, Sonoelastography, Resistive index, Chronic allograft changes, Biopsy, Histopathology

Core Tip: Kidney transplantation is the treatment of choice for patients with end-stage kidney disease. Although short-term outcomes have improved markedly, chronic allograft damage remains a formidable challenge. Early detection of chronic changes is crucial for the optimal well-being of the graft. Biopsy is the gold standard but is invasive, and prone to sampling error and interobserver variation. The resistive index on Doppler is routinely used for the assessment of renal allograft status but its value in chronic renal allograft dysfunction is unclear. Shear wave sonoelastography is a novel imaging technique that has shown promising results in a number of studies.