In this study, we finally constructed the DLRAD model for preoperative prediction of MVI status in ICC patients. The proposed model combined radiomics features from the intratumoral region and the 2mm peritumoral region, and introduced deep transfer learning features based on RENET34, which showed satisfactory prediction performance. Based on the MVI results predicted by this model, we can judge the prognosis of patients, and this finding has important implications for clinical decision making because it can help physicians to more accurately assess the risk of patients and thus formulate individualized treatment plans.
In the process of model building, different machine learning methods are suitable for different tasks, and choosing appropriate algorithms can improve the accuracy and efficiency of the analysis. The model was initially trained and validated by applying different machine learning algorithms for model building, including LR, SVM, KNN and NB. The results showed that the LR and SVM methods were more suitable for our task and better able to analyze the radiomics data, which was consistent with the results of previous studies[21, 22].
In addition to the tumor itself, the peritumoral area is also an important predictor of MVI. Fiz et al[23]. performed non-invasive identification of MVI in intrahepatic cholangiocarcinoma by preoperative PET/CT radiomics features. The results showed that the inclusion of peritumoral features further improved the prediction performance. However, this study did not compare peritumoral features of different sizes and was based on a single-center study of 74 patients. In our study, we not only considered the imaging features inside the tumor, but also focused on the characteristics of the peritumoral region. Through comparative analysis, we found that the features of the peritumoral region had obvious incremental value for the prediction accuracy of the model. This further demonstrates the value of radiomics in the preoperative evaluation of tumors and provides more comprehensive information for clinical practice. In addition, the internal validation cohort model results suggest that the appropriate regional tumor weeks has contribution value, the construction of a model according to the tumor and tumor area 1 mm, 2 mm, 3 mm build the model of AUC LR respectively (0.757, 0.792, 0.645), and the SVM (0.732, 0.754, 0.627); in the external validation cohort LR, (0.744, 0.795, 0.897) and SVM (0.778, 0.94, 0.897) were used. Because the number of external validation cohorts was too limited, we could not conclude that the incremental value of a 2mm peritumoral region on model performance was higher, although this pattern was observed in the internal validation cohorts.
Deep learning techniques have shown great potential for tumor diagnosis and prediction[24, 25]. By analyzing a large amount of tumor image data, deep learning models can extract meaningful features from images, and then predict the pathological characteristics of tumors. Since there are relatively few ICC patients and renet34 transfer learning is more suitable for tasks with relatively limited samples, we used this model to predict microvascular invasion in this study and achieved satisfactory accuracy.
This study has the following advantages over previous studies[23, 26, 27]. First, we explored the value of different machine learning methods for MVI prediction. Secondly, the application of deep transfer learning algorithm improved the prediction accuracy of the model and further enriched the research methods of radiomics. In addition, we extracted features from both intratumoral and peritumoral regions, which more comprehensively reflected the characteristics of the tumor. Nonetheless, this study has some limitations. In future research, we can further explore more advanced deep learning models and optimization algorithms to improve the prediction accuracy and generalization ability of the model. At the same time, we need to expand the sample size to improve the reliability and generalizability of the study, and "virtual biopsy" is our goal.