| [Objective]To explore the value of CT features and radiomics in the differential diagnosis of gastric ectopic pancreas(GEP)and gastric stromal tumor(GST)with the long diameter of less than 3 cm.[Methods]The clinical and CT data of 40 GEP patients and 54 GST patients were retrospectively analyzed,and the age,gender,clinical symptoms,history of digestive diseases,endoscopic ultrasonography and CT results of the two groups were compared.CT findings of the two groups were compared,including long diameter,short diameter,the ratio of long diameter to short diameter(LD/SD),contour,location,border,growth pattern,density,mucosa continuity,prominent enhancement of overlying mucosa,surface dimple,central catheter sign,peritumoral fat-line,the CT attenuation,enhancement attenuation and enhancement grade of each stage.The CT attenuation,enhancement attenuation and enhancement grade between GEP and pancreas were compared.Then the DICOM images of 94 patients were exported,ITK-SNAP software was used to delineate the region of interest,PyRadiomics software was used to extract the radiomics features,and support vector machine(SVM)algorithm was used to model for differential diagnosis between the training set and validation set.Diagnostic efficiency was evaluated by the area under the curve(AUC)of receiver operating characteristic(ROC)curve.[Results]GEP patients was younger than GST patients,and the difference was statistically significant(P<0.001).The diagnostic accuracies of endoscopic ultrasonography and CT for GST were higher than that for GEP.the differences were statistically significant(both P<0.001).There were significant differences in LD/SD,contour,location,border and surface dimple between the two groups(all P<0.05).LD/SD of GEP had the larger LD/SD,and most of GEP lesions were ovoid and round,located in the distal and middle part of the stomach,well or ill defined,and the surface dimple was observed.However,GST lesions were mostly round,located in the proximal and middle of the stomach,well defined and a rare surface dimple.The CT attenuation in plain scan,the CT attenuation and enhancement attenuation in arterial phase and venous phase of GEP were higher than those of GST;most GEP showed significant enhancement,while most GST showed mild to moderate enhancement,the differences were statistically significant(all P<0.05).The CT attenuation in plain scan,the CT attenuation and enhancement attenuation in arterial phase of GEP were lower than those of GST,while the enhancement attenuation values in venous and delayed phase were higher than those of the pancreas.GEP and the pancreas showed obvious enhancement in arterial phase,but the pancreas showed more obviously,and showed mild to moderate enhancement in the delayed phase.And the differences were statistically significant(all P<0.05).A total of 5 features of plain scan,8 features of arterial phase,7 features of venous phase and 4 features of delayed phase were filtrated.The plain scan model,arterial phase model,venous phase model and delayed phase model and the combined phase model with 24 features were established respectively,and the differential diagnosis efficacy was analyzed.The combined phase model had the highest diagnostic efficacy on both the training set and the validation set with the AUC of 0.99(95%CI 0.98～1)and 0,92(95%CI 0.82～1),respectively.[Conclusions]CT features and radiomics have a good value in the differential diagnosis of GEP and GST ≤3 cm in length diameter.The patients’ age,lesions’ LD/SD,contour,location,border and surface dimple have differences between GEP and GST.The CT attenuation in plain scan,the CT attenuation and enhancement attenuation in arterial phase and venous phase of GEP are higher than those of GST.Most GEP show significant enhancement,while most GST show mild to moderate enhancement in the arterial phase.The model with the filtered radiomics features from the plain scan,arterial phase,venous phase and delayed phase has the best diagnostic efficacy... |
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