Radiomics model-based algorithm for preoperative prediction of pancreatic ductal adenocarcinoma grade.

OBJECTIVE: To develop diagnostic radiomic model-based algorithm for pancreatic ductal adenocarcinoma (PDAC) grade prediction. METHODS: Ninety-one patients with histologically confirmed PDAC and preoperative CT were divided into subgroups based on tumor grade. Two histology-blinded radiologists independently segmented lesions for quantitative texture analysis in all contrast enhancement phases. The ratio of densities of PDAC and unchanged pancreatic tissue, and relative tumor enhancement (RTE) in arterial, portal venous, and delayed phases of the examination were calculated. Principal component analysis was used for multivariate predictor analysis. The selection of predictors in the binary logistic model was carried out in 2 stages: (1) using one-factor logistic models (selection criterion was p < 0.1); (2) using regularization (LASSO regression after standardization of variables). Predictors were included in proportional odds models without interactions. RESULTS: There were significant differences in 4, 16, and 8 texture features out of 62 for the arterial, portal venous, and delayed phases of the study, respectively (p < 0.1). After selection, the final diagnostic model included such radiomics features as DISCRETIZED HU standard, DISCRETIZED HUQ3, GLCM Correlation, GLZLM LZLGE for the portal venous phase of the contrast enhancement, and CONVENTIONAL_HUQ3 for the delayed phase of CT study. On its basis, a diagnostic model was built, showing AUC for grade ≥ 2 of 0.75 and AUC for grade 3 of 0.66. CONCLUSION: Radiomics features vary in PDAC of different grades and increase the accuracy of CT in preoperative diagnosis. We have developed a diagnostic model, including texture features, which can be used to predict the grade of PDAC. KEY POINTS: • A diagnostic algorithm based on CT texture features for preoperative PDAC grade prediction was developed. • The assumption that the scanning protocol can influence the results of texture analysis was confirmed and assessed. • Our results show that tumor differentiation grade can be assessed with sufficient diagnostic accuracy using CT texture analysis presented in this study.

Computed tomography-based radiomics approach in pancreatic tumors characterization.

Radiomics (or texture analysis) is a new imaging analysis technique that allows calculating the distribution of texture features of pixel and voxel values depend on the type of ROI (3D or 2D), their relationships in the image. Depending on the software, up to several thousand texture elements can be obtained. Radiomics opens up wide opportunities for differential diagnosis and prognosis of pancreatic neoplasias. The aim of this review was to highlight the main diagnostic advantages of texture analysis in different pancreatic tumors. The review describes the diagnostic performance of radiomics in different pancreatic tumor types, application methods, and problems. Texture analysis in PDAC is able to predict tumor grade and associates with lymphovascular invasion and postoperative margin status. In pancreatic neuroendocrine tumors, texture features strongly correlate with differentiation grade and allows distinguishing it from the intrapancreatic accessory spleen. In pancreatic cystic lesions, radiomics is able to accurately differentiate MCN from SCN and distinguish clinically insignificant lesions from IPMNs with advanced neoplasia. In conclusion, the use of the CT radiomics approach provides a higher diagnostic performance of CT imaging in pancreatic tumors differentiation and prognosis. Future studies should be carried out to improve accuracy and facilitate radiomics workflow in pancreatic imaging.

Metastasis of endometrial cancer to right hemidiaphragm: A case report.

INTRODUCTION: Tumors of the diaphragm are uncommon. The overwhelming number of cases is metastatic combined with metastases to the liver, lungs and other organs. Only a minority of cases are described as solitary lesions. CASE PRESENTATION: Fifty-five years old female with a history of radical curative surgery for pT3N0M0 endometrial cancer eight years ago was admitted to the Department of Thoracic Surgery with a feeling of discomfort in the right hypochondrium. The contrast-enhanced MDCT revealed a large, well-circumscribed lesion of the right hemidiaphragm deforming upper contour of the liver. A clear boundary between the lesion and the liver suggested former's diaphragmatic origin. PET-CT did not show any distant metastasis. Intraoperative revision revealed a tumor growing from the dome of the diaphragm with well-defined contours and without any signs of lung involvement. The diaphragmotomy was performed. The morphological study with immunohistochemistry showed an endometrial carcinoma metastasis to the diaphragm. CONCLUSION: The diaphragm lesions can have various etiology, but a probability of tumor metastasis after a previous radical surgery should not be excluded. Preoperative differential diagnostics can be difficult, leaving surgical treatment followed by a pathology study as the most informative diagnostic method of tumor morphology.