ObjectiveTo assess the feasibility of intravoxel incoherent motion diffusion-weighted imaging (IVIM) in evaluating microvessel density (MVD) and microvascular invasion (MVI) of hepatocellular carcinoma (HCC).MethodsRat models were established to be scanned by IVIM. HCC lesions corresponding to IVIM image were examined pathologically to get data of MVD and MVI. Spearman correlation analysis was used to compare the apparent diffusion coefficient (ADC), D, D*, and f with MVD, independent samples t test was used to compare ADC, D, D*, and f between MVI (+) and MVI (–) groups.ResultsFifty HCC lesions were included finally. ADC and D values both showed a negative correlation with MVD (r=–0.406, P=0.003; r=–0.468, P=0.001), D* and f showed no statistical correlation with MVD (P=0.172, 0.074, respectively). The differences in ADC and all the IVIM parameters (D, D*, and f) between MVI (+) and MVI (–) HCCs were not statistically significant (P=0.393, 0.395, 0.221, 0.550).ConclusionADC and D can be used to evaluate MVD of HCC, but ADC and IVIM parameters were limited in evaluating MVI.
Objective To determine feasibility of texture analysis of CT images for the discrimination of nonhypervascular pancreatic neuroendocrine tumor (PNET) from pancreatic ductal adenocarcinoma (PDAC). Methods CT images of 15 pathologically proved as PNETs and 30 PDACs in West China Hospital of Sichuan University from January 2009 to January 2017 were retrospectively analyzed. Results Thirty best texture parameters were automatically selected by the combination of Fisher coefficient (Fisher)+classification error probability combined with average correlation coefficients (PA)+mutual information (MI). The 30 texture parameters of arterial phase (AP) CT images were distributed in co-occurrence matrix (18 parameters), run-length matrix (10 parameters), and autoregressive model (2 parameters). The distribution of parameters in portal venous phase (PVP) were co-occurrence matrix (15 parameters), run-length matrix (10 parameters), histogram (1 parameter), absolute gradient (1 parameter), and autoregressive model (3 parameters). In AP and PVP, the parameter with the highest diagnostic performance were both Teta2, and the area under curve (AUC) value was 0.829 and 0.740 (P<0.001,P=0.009), respectively. By the B11 of MaZda, the misclassification rate of raw data analysis (RDA)/K nearest neighbor classification (KNN), principal component analysis (PCA)/KNN, linear discriminant analysis (LDA)/KNN, and nonlinear discriminant analysis (NDA)/artificial neural network (ANN) was 28.89% (13/45), 28.89% (13/45), 0 (0/45), and 4.44% (2/45), respectively. In PVP, the misclassification rate of RDA/KNN, PCA/KNN, LDA/KNN, and NDA/ANN was 35.56% (16/45), 33.33% (15/45), 4.44% (2/45), and 11.11% (5/45), respectively. Conclusions CT texture analysis is feasible in the discrimination of nonhypervascular PNET and PDAC. Teta2 is the parameter with the highest diagnostic performance, and in AP, LDA/KNN modality has the lowest misclassification rate.
Objective To access the diagnostic performance of CT texture analysis to differentiate atypical pancreatic solid pseudopapillary tumor (SPT) from pancreatic ductal adenocarcinoma (PDAC). Methods CT images of 26 patients with pathologically proved atypical SPT and 52 patients with PDAC were analyzed. 3D regions of interest (ROIs) on arterial phase (AP) and portal venous phase (PVP) images were drawn by ITK-Snap software. A.K. software (GE company, USA) was used to extract texture features for the discrimination of atypical SPT and PDAC. After removing redundancy (by a correlation analysis through R software), texture features were selected by single-factor and multi-factor logistic regression, and logistic regression model was finally established. Receiver operating characteristic (ROC) analysis was performed to assess the diagnostic performance of single texture feature and logistic model. Results A total of 792 texture features ［396 of AP, 396 of PVP］ from AP and PVP CT images were obtained by A.K. software. Of these, 61 texture features (35 of AP, 26 of PVP) were selected by R software (result of correlation analysis showed that correlation coefficient >0.7). Two texture features, including MinIntensity and Correlation_AllDirection_offset1_SD, were selected to establish logistic model. The sensitivity and specificity of these 2 texture features were 71.15% and 76.92%, 63.46% and 76.92% respectively, the area under curve ( AUC) were 0.740 and 0.754 respectively. The model’s sensitivity and specificity were 73.08% and 80.77% respectively, the AUC value was 0.796. There was no significance among the model, MinIntensity, and Correlation_AllDirection_offset1_SD (P>0.05). Conclusions CT texture analysis of 3D ROI is a quantitative method for differential diagnosis of atypical SPT from PDAC.
Objective To explore CT features that can be used to identify nonhypervascular pancreatic neuroendocrine neoplasm (pNEN) and pancreatic ductal adenocarcinoma (PDAC). Methods The patients with pathologically confirmed the pNEN and PDAC were retrospectively included from May 2010 to May 2017. The CT features were analyzed. The CT features were extracted by the multivariate logistic regression, and their diagnostic performances were calculated. Results Forty patients with the nonhypervascular pNEN (33 unfunctional, 7 functional) and 80 patients with the PDAC were included in this study. The features of significant differences between the nonhypervascular pNEN and the PDAC included: the location, long diameter, margin, uniform lesions, calcification, and vascular shadows of the lesion (P<0.05). The margin ［OR=14.63, 95% CI (2.82, 75.99)］, calcification ［OR=4.00, 95% CI (1.03, 15.59)］, and location ［OR=3.09, 95% CI(1.19, 7.99)］ of the lesion could independently identify the nonhypervascular pNEN. The multivariate logistic regression model of the differential diagnosis of the nonhypervascular pNEN and PDAC was obtained through the CT features of significant differences. The diagnostic sensitivity was 70.00%, 95% CI (53.5,83.4); specificity was 83.54%, 95% CI (73.5, 90.9); and area under the receiver operating curve was 0.824, 95% CI (0.743, 0.887). Conclusions Multivariate logistic regression model of CT features is helpful for differential diagnosis of nonhypervascular pNEN and PDAC. Features of margin and calcification of lesion are more valuable in differential diagnosis of nonhypervascular pNEN and PDAC.
ObjectiveTo investigate current status and hot issues of pancreatic neuroendocrine neoplasm (pNEN) imaging research.MethodsThe literatures focusing on pNEN and published from 1998 to 2018 were retrieved from the core database of Web of Science. The quantitative analysis of literatures was then conducted by using the CiteSpace software based on the bibliometrics method. The research trend was then summarized systematically and the potential research fronts and focuses were explored.ResultsA total of 190 articles in the field of pNEN imaging research were retrieved, and the top three countries in the literatures were the United States, Germany, and Italy. The clustering of co-citation of pNEN included the endoscopic ultrasound, current diagnosis, prospective evaluation, cystic pancreatic neuroendocrine tumor, hypervascular neuroendocrine tumor, nonfunctioning pancreatic neuroendocrine tumor, intravoxel incoherent motion, and metastastic lesion. The hot of keywords in the field of pNEN included the fine needle aspiration, CT, diagnosis, pancreas, cancer, neuroendocrine tumor, neoplasm, carcinoma, and management. The hot keywords clustering had the neuroendocrine tumor, pancreatic mass size, non-hyperfunctioning neuroendocrine tumor, CT appearance, metastatic lesion, ancillary studies, somatostatin analogues, somatostatinoma, intraoperative ultrasound, and multiple endcorine neoplasia 1.ConclusionAccurate imaging diagnosis of pNEN is still a hot issue in this field.