Objective:To investigate the value of nomogram model based on CT features in differentiating ectopic pancreas (EP) from gastrointestinal stromal tumors (GIST) with a long diameter less than 3 cm.Methods:This study was a case-control study. The clinical and imaging data of 43 patients with EP and 90 patients with GIST confirmed by pathology in the Affiliated Hospital of Guizhou Medical University from August 2013 to March 2024 were retrospectively analyzed. Preoperative CT images were analyzed to obtain qualitative features (number of lesions, location, morphology, growth pattern, borders, cystic degeneration, calcification, ulceration, catheter sign, central umbilication) and quantitative features (lesion long diameter, short diameter, long/short diameter, lesion and normal pancreas arterial-phase and venous-phase CT values, and enhancement ratio). Statistical analyses, including independent sample t-tests, Mann-Whitney U tests, χ2 tests, and Fisher exact tests, were performed to compare CT characteristics between the two groups. Binary logistic regression analysis was used to obtain independent predictors to identify the two groups, to establish a joint model, and to draw a nomogram. The discriminative performance of the independent predictors and the combined model was assessed using receiver operating characteristic (ROC) curves, while calibration curves were used to evaluate model fit. Results:The differences in age, location, morphology, border, catheter sign, central umbilication, short diameter, long/short diameter, arteriovenous phase enhancement CT value and arteriovenous phase enhancement ratio were statistically significant between the EP group and the GIST group (all P<0.05). The logistic analysis showed that the differences in age ( OR=0.920, 95% CI 0.885-0.956, P<0.001), border ( OR=5.994, 95% CI 2.111-17.022, P=0.001), long/short diameter ( OR=7.820, 95% CI 1.841-33.224, P=0.005), and venous phase enhancement ratio ( OR=8.847, 95% CI 1.103-70.972, P=0.040) were the independent predictors for distinguishing EP from GIST, and the area under the ROC curve (AUC) were 0.782 (95% CI 0.698-0.866), 0.684 (95% CI 0.600-0.767), 0.705 (95% CI 0.607-0.803), and 0.693 (95% CI 0.605-0.781), respectively. Combined age, border, long diameter/short diameter and venous phase enhancement ratio were plotted in a nomogram with an AUC of 0.881 (95% CI 0.817-0.945), sensitivity and specificity of 74.4% and 93.3%, respectively. The calibration curve demonstrated a strong agreement between predicted and actual probabilities (Hosmer-Lemeschow test, P=0.267). Conclusions:CT imaging reveals significant differences between EP and small GISTs (<3 cm). EP is more likely when patients are younger and lesions exhibit indistinct borders, a higher long-to-short diameter ratio, and greater venous-phase enhancement. The nomogram derived from CT features provides a valuable tool for differentiating EP from GIST.

Objective:To investigate the value of nomogram model based on CT features in differentiating ectopic pancreas (EP) from gastrointestinal stromal tumors (GIST) with a long diameter less than 3 cm.Methods:This study was a case-control study. The clinical and imaging data of 43 patients with EP and 90 patients with GIST confirmed by pathology in the Affiliated Hospital of Guizhou Medical University from August 2013 to March 2024 were retrospectively analyzed. Preoperative CT images were analyzed to obtain qualitative features (number of lesions, location, morphology, growth pattern, borders, cystic degeneration, calcification, ulceration, catheter sign, central umbilication) and quantitative features (lesion long diameter, short diameter, long/short diameter, lesion and normal pancreas arterial-phase and venous-phase CT values, and enhancement ratio). Statistical analyses, including independent sample t-tests, Mann-Whitney U tests, χ2 tests, and Fisher exact tests, were performed to compare CT characteristics between the two groups. Binary logistic regression analysis was used to obtain independent predictors to identify the two groups, to establish a joint model, and to draw a nomogram. The discriminative performance of the independent predictors and the combined model was assessed using receiver operating characteristic (ROC) curves, while calibration curves were used to evaluate model fit. Results:The differences in age, location, morphology, border, catheter sign, central umbilication, short diameter, long/short diameter, arteriovenous phase enhancement CT value and arteriovenous phase enhancement ratio were statistically significant between the EP group and the GIST group (all P<0.05). The logistic analysis showed that the differences in age ( OR=0.920, 95% CI 0.885-0.956, P<0.001), border ( OR=5.994, 95% CI 2.111-17.022, P=0.001), long/short diameter ( OR=7.820, 95% CI 1.841-33.224, P=0.005), and venous phase enhancement ratio ( OR=8.847, 95% CI 1.103-70.972, P=0.040) were the independent predictors for distinguishing EP from GIST, and the area under the ROC curve (AUC) were 0.782 (95% CI 0.698-0.866), 0.684 (95% CI 0.600-0.767), 0.705 (95% CI 0.607-0.803), and 0.693 (95% CI 0.605-0.781), respectively. Combined age, border, long diameter/short diameter and venous phase enhancement ratio were plotted in a nomogram with an AUC of 0.881 (95% CI 0.817-0.945), sensitivity and specificity of 74.4% and 93.3%, respectively. The calibration curve demonstrated a strong agreement between predicted and actual probabilities (Hosmer-Lemeschow test, P=0.267). Conclusions:CT imaging reveals significant differences between EP and small GISTs (<3 cm). EP is more likely when patients are younger and lesions exhibit indistinct borders, a higher long-to-short diameter ratio, and greater venous-phase enhancement. The nomogram derived from CT features provides a valuable tool for differentiating EP from GIST.

Objective To evaluate CT vs.MRI in the intrapancreatic and relevant extrapancreatic findings of acute pancreatitis (AP).Methods The clinical data and image findings of 52 AP cases from Jan 2015 to Jun 2017 were analyzed retrospectively.Results CT is comparable to MRI in the diagnostic value of pancreatic enlargement and pancreatic necrosis (all P ＞ 0.05).Compared to CT,MRIwas superior in detecting the peripancreatic exudes,thickening of renal fascia,pleural effusion and abdominal wall edema (all P ＜ 0.01).In favor of MRI,there was significant difference in detection of gallbladder stones and choledocholithiasis,and hepatic swelling,hepatic fatty infiltration.Conclusions Both CT and MRI are significantly helpful to the early precise diagnosis of AP,while MRIis superior in showing etiology,pancreatic hemorrhage and necrosis,extrapancreatic lesions.

Objective To investigate the diagnostic value of calcification and cystic lesion of CT findings in differentiating pancreatic head ductal carcinoma (PHDA)from mass-forming chronic pancreatitis (MFCP)of the pancreatic head.Methods The clinic data and CT findings of 30 cases with PHDA and 24 cases with MFCP of the pancreatic head,which were confirmed by surgery and pathology were analyzed retrospectively.The images were reviewed independently by two expert radiologists with a double-blind method.An independent sample t test and chi-square test were used to compare the data of imaging findings between two groups.Results ① Calcification was found in 14 cases (58.33%)with MFCP and in 3 cases (10%)with PHDA (P＜0.001).The percentage of patchy,punctate and mixed calcification were 28.57% (n=4),14.29% (n=2)and 57.14% (n=8)in MFCP,0% (n=0),66.67% (n=2)and 33.33% (n=1) in PHDA,respectively.② Necrotic cyst was founded in 7 cases (29.17%)with MFCP and 18 cases (60%)with PHDA(P＜0.05). Pseudocysts were demonstrated in 14 cases (58.33%)with MFCP and in 3 cases (10%)with PHDA (P＜0.001).Honeycombed change with tension within or around the lesion were demonstrated only in patients with MFCP.In addition,normal tissue of the pancreas was found within the lesion in 11 cases (45.83%)of MFCP and none in PHDA,which showed significant difference between two groups.Conclusion Mixed calcification and honeycomb with tension of CT findings are of significant value in differentiating PHDA from MFCP of the pancreatic head.