Retrospective Study
Copyright ©The Author(s) 2019. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Apr 28, 2019; 25(16): 1986-1996
Published online Apr 28, 2019. doi: 10.3748/wjg.v25.i16.1986
Dual energy computed tomography for detection of metastatic lymph nodes in patients with hepatocellular carcinoma
Yu-Rong Zeng, Qi-Hua Yang, Qing-Yu Liu, Jun Min, Hai-Gang Li, Zhi-Feng Liu, Ji-Xin Li
Yu-Rong Zeng, Qi-Hua Yang, Qing-Yu Liu, Ji-Xin Li, Department of Radiology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, Guangdong Province, China
Jun Min, Department of Hepatobiliary Surgery, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, Guangdong Province, China
Hai-Gang Li, Department of Pathology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, Guangdong Province, China
Zhi-Feng Liu, Department of Radiology, Zengcheng District People’s Hospital of Guangzhou, Guangzhou 511300, Guangdong Province, China
Author contributions: Zeng YR and Yang QH contributed equally to this work; Zeng YR, Yang QH, and Liu QY designed the research; Zeng YR, Yang QH, Min J, Li HG, and Liu ZF performed the research; Li JX contributed technical guidance and operation; Zeng YR, Yang QH, Min J, and Liu ZF analyzed the data; Zeng YR, Yang QH, and Liu QY wrote the paper.
Institutional review board statement: The study was reviewed and approved by the institutional review board of Sun Yat-sen Memorial Hospital.
Informed consent statement: Informed consent was waived by the ethics committee of Sun Yat-sen Memorial Hospital.
Conflict-of-interest statement: There is no conflict of interest associated with any of the senior author or other coauthors who contributed their efforts in this manuscript.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (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: Qing-Yu Liu, PhD, Attending Doctor, Professor, Department of Radiology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, 107 West Yanjiang Road, Guangzhou 510120, Guangdong Province, China. liuqy@mail.sysu.edu.cn
Telephone: +86-13694201711 Fax: +86-20-81332702
Received: February 2, 2019
Peer-review started: February 6, 2019
First decision: March 5, 2019
Revised: March 14, 2019
Accepted: March 24, 2019
Article in press: March 24, 2019
Published online: April 28, 2019
Processing time: 83 Days and 13.6 Hours
ARTICLE HIGHLIGHTS
Research background

Regional lymph node metastasis in patients with hepatocellular carcinoma (HCC) is not uncommon, and is often under- or misdiagnosed. Regional lymph node metastasis is associated with a negative prognosis in patients with HCC, and surgical resection of lymph node metastasis is considered feasible and efficacious in improving the survival and prognosis. It is critical to characterize lymph node preoperatively. There is currently no consensus regarding the optimal method for the assessment of regional lymph nodes in patients with HCC.

Research motivation

Dual-energy computed tomography (CT) can provide quantitative information with monochromatic spectral images, material decomposition images, spectrum curves, and effective atomic number images. The role of dual-energy CT parameters in the evaluation of malignant lymph nodes has been reported with excellent results. However, there have been no dual-energy CT studies regarding lymph node assessment in HCC.

Research objectives

The main objective of our study was to evaluate the diagnostic value of dual energy CT parameters [such as iodine concentrations (IC), normalized IC (NIC), and slope of the spectral curve (λHU)] in regional lymph node assessment for HCC patients.

Research methods

In this retrospective study, a total of 156 lymph nodes (33 patients with 104 non-metastatic and 10 patients with 52 metastatic) from 43 patients were finally included. According to the lymph node status, the lymph nodes were divided into group P (52 metastatic) and group N (104 non-metastatic). According to the active hepatitis diagnosis standard, the lymph nodes in groups P and N were further divided into an active hepatitis group (group P1, n = 34; group N1, n = 73) and a non-active hepatitis group (group P2, n = 18; group N2, n = 31), respectively. All patients underwent three-phase dual-energy CT scan preoperatively [arterial phase (AP), portal phase (PP), and delayed phase (DP)]. The maximal short axis diameter (MSAD), IC, NIC, and λHU of each group in the AP, PP, and DP were analyzed.

Research results

The MSAD, IC, NIC, and λHU showed statistical differences between groups P and N (P < 0.05 for all) in dual-energy CT scans in all the three phases. The diagnostic value of IC, NIC, and λHU in the PP to distinguish benign from metastatic lymph nodes was the best among the three phases (AP, PP, and DP), with a sensitivity up to 81.9%, 83.9%, and 81.8%, and specificity up to 82.4%, 84.1% and 84.1%, respectively. To distinguish benign from metastatic lymph nodes, the diagnostic value of combined analyses of MSAD with IC, NIC, or λHU in PP was superior to the dual energy CT parameters alone, with a sensitivity up to 84.5%, 86.9%, and 86.2%, and a specificity up to 83.0%, 93.6% and 89.8%, respectively. Between groups P1 and P2 and groups N1 and N2, only IC, NIC, and λHU between groups N1 and N2 in the PP had a statistically significant difference (P < 0.05).

Research conclusions

Dual-energy CT parameters (IC, NIC, and λHU) are sensitive and specific, and can help to differentiate benign from metastatic lymph nodes in patients with HCC, especially in PP CT scans. The diagnostic efficacy of combined analysis of MSAD with IC, NIC, or λHU values is superior to using any single parameter alone. Active hepatitis does not deteriorate the capabilities for characterization of metastatic lymph nodes.

Research perspectives

The future direction in this field will probably focus on the comparison of diagnostic efficacy of different imaging methods to differentiate benign from metastatic lymph nodes in patients with HCC, e.g., between dual-energy CT and magnetic resonance imaging.