Comparison between CT Net enhancement and PET/CT SUV for N staging of gastric cancer: A case series

Background:The therapeutic approach of gastric cancer strictly depends on TNM staging mainly pro-vided by CT and PET/CT. However, the lymph node size criterion as detected by MDCT causes a poordifferential diagnosis between reactive and metastatic enlarged lymph nodes with low specificity values.Our study aims to compare 320-row CT Net enhancement andfluorine-18fluoro-2-deoxy-D-glucosepositron emission tomography/computed tomography (F-FDG PET/CT) SUV for N staging of gastriccancer.Materials and methods:45 patients with histologically proven gastric cancer underwent CT and F-FDGPET/CT. Two radiologists in consensus evaluated all images and calculated the CT Net enhancement andF-FDG PET/CT SUV for N staging, having the histologicalfindings as the reference standard. CT and F-FDGPET/CT sensitivity, specificity, diagnostic accuracy, positive and negative predictive values (PPV and NPV)were evaluated and compared by using the Mc Nemar test.Results:The histological examination revealed nodal metastases in 29/45 cases (64%). CT Net enhance-ment obtained sensitivity, specificity, accuracy, PPV and NPV of 90%, 81%, 87%, 90% and 81%, respectively.F-FDG PET/CT SUV obtained sensitivity, specificity, accuracy, PPV and NPV of 66%, 88%, 73%, 90% and 58%,respectively. No statistically significant difference between the two imaging modalities was found(p¼0.1).Conclusion:CT Net enhancement represents an accurate tool for N staging of gastric cancer and could beconsidered as the CT corresponding quantitative parameter of F-FDG PET/CT SUV. It could be applied inthe clinical practice for differentiating reactive lymph nodes from metastatic ones improving accuracyand specificity of CT.©2017 The Author(s). Published by Elsevier Ltd on behalf of IJS Publishing Group Ltd. This is an openaccess article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).