Diagnostic accuracy of dual-energy CT-based nomograms to predict
lymph node metastasis in gastric cancer
Received: 19 January 2018 /Revised: 5 April 2018 /Accepted: 12 April 2018
European Society of Radiology 2018
Objectives To develop and validate a dual-energy CT based nomogram for the preoperative prediction of lymph node metastasis
(LNM) in patients with gastric cancer (GC).
Methods A total of 210 surgically confirmed GC patients (159 males, 51 females; mean age: 59.8 ± 7.7 years, range: 28-79 years)
who underwent spectral CT scans were retrospectively enrolled and split into a primary cohort (n = 140) and validation cohort (n
= 70). Clinical information and follow-up data including overall survival (OS) and progression-free survival (PFS) were collect-
ed. The iodine concentration (IC) of the primary tumors at the arterial phase (AP) and venous phase (VP) were measured and then
normalized to the aorta (nICs). Univariate, multivariable logistic regression and Cox regression analyses were performed to
screen predictive indicators for LNM and outcome. A nomogram for risk factors of LNM was developed, and its performance
was measured using the ROC, accuracy and Harrell’s concordance index (C-index).
Results Tumor thickness, Borrmann classification and ICVP were independent predictors of LNM. The nomogram was signif-
icantly associated with LN status (p < 0.001). It yielded an AUC of 0.793 [95% confidence interval (95% CI), 0.678-0.908] and
an accuracy of 0.757 (95% CI, 0.640-0.852) in the internal-validation cohort. The nomogram also exhibited a prognostic ability
with C-indices of 0.675 (95% CI, 0.571-0.779; p < 0.001) for PFS and 0.643 (95% CI, 0.518-0.768; p =0.025)forOS.
Conclusion This study presented a dual-energy quantification-based nomogram, which can be used to facilitate the preoperative
individualized prediction of LNM in patients with GC.
• This study first developed and internally validated a dual-energy CT-based nomogram to predict lymph node metastasis in
patients with gastric cancer.
• The nomogram incorporated the clinical risk factors and iodine concentration, which would enable superior preoperative
individual prediction of lymph node metastasis and add more information for the optimal therapeutic strategy.
• The nomogram also exhibited a significant prognostic ability for progression-free and overall survival.
Keywords Gastric cancer
Lymph node metastasis
AP Arterial phase
AUC Area under the curve
EUS Endoscopic ultrasonography
GC Gastric cancer
GSI Gem spectral imaging
IC Iodine concentration
LNM Lymph node metastasis
MRI Magnetic resonance imaging
MVD Microvessel density
Jing Li and Mengjie Fang contributed equally to this work.
* Jianbo Gao
Department of Radiology, The First Affiliated Hospital of Zhengzhou
University, No. 1, East Jianshe Road, Zhengzhou 450052, Henan,
Department of Radiology, The Affiliated Cancer Hospital of
Zhengzhou University (Henan Cancer Hospital),
Zhengzhou 450008, Henan, China
CAS Key Laboratory of Molecular Imaging, Institute of Automation,
Chinese Academy of Sciences, Beijing 100190, China
University of Chinese Academy of Sciences, Beijing 100190, China