AUTHOR=Song Gesheng , Li Panpan , Wu Rui , Jia Yuping , Hong Yu , He Rong , Li Jinye , Zhang Ran , Li Aiyin 

TITLE=Development and validation of a high-resolution T2WI-based radiomic signature for the diagnosis of lymph node status within the mesorectum in rectal cancer

JOURNAL=Frontiers in Oncology

VOLUME=Volume 12 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/oncology/articles/10.3389/fonc.2022.945559

DOI=10.3389/fonc.2022.945559

ISSN=2234-943X

ABSTRACT=Purpose: To explore the feasibility of a high-resolution T2-weighted imaging (HR-T2WI) based radiomics prediction model for diagnosing metastatic lymph nodes within mesorectum in rectal cancer.
Method: A total of 604 lymph nodes (306 metastatic and 298 non-metastatic) from 166 patients were obtained. All patients underwent HR-T2WI examination and total mesorectal excision (TME) surgery. Four kinds of segmentation methods were used to select region of interest (ROI), including method 1 along the border of lymph nodes (LNs); method 2 along the expanded border of LNs with additional 2-3mm; method 3 covering the border of LNs only; method 4 a circle region only within LNs. A total of 1,409 features were extracted for each method. Variance threshold method, Select K Best and Lasso algorithm were used to reduce the dimension. All LNs were divided into training and validation sets. 5-fold cross validation was used to build the logistic model, which was evaluated by the receiver operating characteristic (ROC) with four indicators including area under curve (AUC), accuracy (ACC), sensitivity (SE) and specificity (SP). Three radiologists with different working experience in diagnosing rectal diseases assessed LN metastasis respectively. The diagnostic efficiencies with each of four segmentation methods and three radiologists were compared each other.
Results: For the test set, the AUCs of four segmentation methods were 0.820, 0.799, 0.764 and 0.741; the ACCs were 0.725, 0.704, 0.709 and 0.670; the SEs were 0.756, 0.634, 0.700 and 0.589; and the SPs were 0.696, 0.772, 0.717 and 0.750, respectively. There was no statistically significant difference in AUC between the four methods(p>0.05). The method 1 had the highest values of AUC, ACC and SE. For three radiologists, the overall diagnostic efficiency was moderate. The corresponding AUCs were of 0.604, 0.634 and 0.671, the ACCs were of 0.601, 0.632 and 0.667, the SEs were of 0.366, 0.552 and 0.392, and the SPs were of 0.842, 0.715 and 0.950, respectively.
Conclusions: 
The proposed HR-T2WI-based radiomic signature exhibited a robust performance on predicting mesorectal LN status and could potentially be used for clinicians in order to determine the status of metastatic LNs in rectal cancer patients.