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World J Gastrointest Surg. Jan 27, 2024; 16(1): 21-28
Published online Jan 27, 2024. doi: 10.4240/wjgs.v16.i1.21
Added value of ratio of cross diameters of the appendix in ultrasound diagnosis of acute appendicitis
Feng-Wa Gu, Si-Ze Wu
Feng-Wa Gu, Si-Ze Wu, Department of Ultrasound, The First Affiliated Hospital of Hainan Medical University, Haikou 570102, Hainan Province, China
Author contributions: Gu FW participated in the study design, obtained the materials, analyzed the data, and wrote the first manuscript; Wu SZ participated in the study design, data obtaining and analysis, and wrote and revised the manuscript; all authors read and approved the final manuscript.
Institutional review board statement: The study was approved by the ethics committee of First Affiliated Hospital of Hainan Medical University.
Informed consent statement: No informed consent was required, because the data are anonymized.
Conflict-of-interest statement: No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article.
Data sharing statement: Technical appendix, statistical code, and dataset available from the corresponding author at wsz074@aliyun.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: Si-Ze Wu, MD, Chief Doctor, Professor, Department of Ultrasound, The First Affiliated Hospital of Hainan Medical University, No. 31 Longhua Road, Haikou 570102, Hainan Province, China. wsz074@aliyun.com
Received: October 2, 2023
Peer-review started: October 2, 2023
First decision: December 6, 2023
Revised: December 13, 2023
Accepted: December 28, 2023
Article in press: December 28, 2023
Published online: January 27, 2024
Processing time: 114 Days and 16.3 Hours
Abstract
BACKGROUND

The maximum outer diameter (MOD) of the appendix is an essential parameter for diagnosing acute appendicitis, but there is space for improvement in ultrasound (US) diagnostic performance.

AIM

To investigate whether combining the ratio of the cross diameters (RATIO) of the appendix with MOD of the appendix can enhance the diagnostic performance of acute appendicitis.

METHODS

A retrospective study was conducted, and medical records of 233 patients with acute appendicitis and 112 patients with a normal appendix were reviewed. The MOD and RATIO of the appendix were calculated and tested for their diagnostic performance of acute appendicitis, both individually and in combination.

RESULTS

The RATIO for a normal appendix was 1.32 ± 0.16, while for acute appendicitis it was 1.09 ± 0.07. The cut-off value for RATIO was determined to be ≤ 1.18. The area under the receiver operating characteristic curve (AUC) for diagnosing acute appendicitis using RATIO ≤ 1.18 and MOD > 6 mm was 0.870 and 0.652, respectively. There was a significant difference in AUC between RATIO ≤ 1.18 and MOD > 6 mm (P < 0.0001). When comparing the combination of RATIO ≤ 1.18 and MOD > 6 mm with MOD > 6 mm alone, the combination showed increased specificity, positive predictive value (PPV), and AUC. However, the sensitivity and negative predictive value decreased.

CONCLUSION

Combining RATIO of the appendix ≤ 1.18 and MOD > 6 mm can significantly improve the specificity, PPV, and AUC in the US diagnosis of acute appendicitis.

Keywords: Acute appendicitis; Diameter; Ratio; Diagnosis; Ultrasound

Core Tip: The maximum outer diameter (MOD) of the appendix has been an essential criterion for diagnosing acute appendicitis, but there is room for improvement in terms of sensitivity, specificity, and accuracy. In this study, we established a new parameter, the ratio of cross diameters on the transverse section of the appendix, for diagnosing acute appendicitis using ultrasound imaging. Combining this parameter with the MOD of the appendix can enhance diagnostic performance, making it more valuable in clinical practice.