Objective To study the distribution characteristics of intraperitoneal free gas and the location value of the site of gastrointestinal perforation using multi-slice CT (MSCT).Methods 60 cases of gastrointestinal perforation were retrospectively collected.The distribution of the intraperitoneal free gas in CT image was analyzed and observed.The digestive tract were divided to the upper digestive tract and the lower digestive tract by Treitz ligament.The distribution of the intraperitoneal free gas was analyzed using χ2 test.The distribution of the intraperitoneal free gas between each different perforational site was analyzed.Results 38 cases of the site of gastrointestinal perforation located in upper gastrointestinal tract and 22 cases located in lower gastrointestinal tract,there was statistically significant difference between the upper digestive tract and the lower digestive tract about the distribution of the intraperitoneal free gas(χ2=22.33,P<0.001).In the cases of upper gastrointestinal tract perforation,13 cases of the site located in stomach and 25 cases located in doudenum,there was no statistically significant difference between stomach and duodenum(χ2=1.97,P>0.05).In the cases of lower gastrointestinal tract perforation,11 cases of the site located in bowel and 11 cases located in colon,there was statistically significant difference between bowel and colon(χ2=8.98,P<0.05).Conclusion The MSCT distribution of the intraperitoneal free gas has important value in localization diagnosis of gastrointestinal perforation.

Objective:To assess the diagnostic value of whole-lesion intravoxel incoherent motion diffusion weighted imaging (IVIM-DWI) in differentiating benign and malignant thyroid nodules based on turbo spin echo (TSE) sequence.Methods:Totally 57 patients with thyroid nodules diagnosed by pathology were prospectively collected at the Affiliated Lianyungang Hospital of Xuzhou Medical University from March 2019 to December 2019. A total of 62 nodules were included for analysis, including 27 benign nodules and 35 malignant nodules. All patients underwent routine MRI scan and IVIM-DWI based on TSE sequence before surgery. The regions of interest were drawn along the edge of the lesion on multiple consecutive slices to cover the entire nodule, and the apparent diffusion coefficient (ADC), diffusivity (D), pseudo-diffusivity (D *) and quantitation of perfusion fraction (f) values were measured, and the mean value of the multilayer measurement was recorded for further analysis. The differences of the parameters between benign and malignant thyroid nodules were analyzed using independent samples ttest (normal distribution) and Mann-Whitney U test (non-normal distribution). The diagnostic efficacy of parameters with statistical significance was evaluated using the receiver operating characteristics (ROC) curve. Results:The ADC, D and D *values in the malignant nodules were lower than those in benign nodules, the differences were statistically significant ( t=3.821, P=0.001; t=2.034, P=0.046).There were no statistical differences of D * and f values ( t=-1.170, P=0.247; Z=-0.559, P=0.577).The optimal cut-off values of ADC and D were 1.90×10 -3mm 2/s and 1.10×10 -3mm 2/s, with both sensitivity of 81.5%, specificity of 73.5% and 61.8%, respectively. The area under ROC curve of ADC and D were 0.782 and 0.688, and the statistical difference was found ( Z=2.098, P=0.040). Conclusion:The whole-lesion IVIM parameters (ADC and D) based on the TSE sequence provide imaging features for preoperative differentiation of benign and malignant nodules of the thyroid gland.