Objective To study the application value of iodixanol in gemstone spectral imaging with low CT dosage.Methods Forty hundred and twenty -six cancer patients with normal kidney function were selected .All of them underwent enhanced gemstone spectral CT scan with low dosage .They were individed into two groups with random number table,including observation group(n=213) and control group(n=213).The observation group was injected isotonic iodixanol ( 270 mgI/mL ) intravenously , while the control group was injected hypertronic iohexol (350mgI/mL) intravenously.With the same injection speed,the acute adverse reaction within 1h and delayed adverse reaction between 1h～7d were recorded.Meanwhile,the changes of Scr and Ccr ,the occurrence rate of contrast -induced nephropathy(CIN) and short -term prognosis were also recorded.Results Fifty-three patients occurred acute adverse reaction,among them 18 cases(8.45％) were in the observation group,35 cases(16.43％) were in the control group,there was statistically significant difference between the two groups (χ2 =10.791,P<0.05).Three patients(1.50％) of the control group occurred delayed adverse reaction ,no one was in the observation group .The adverse reaction disappeared after some time .Two kinds of contrast media caused slight increase of Scr and decrease of Ccr,but there were no statistically significant differences between them (all P>0.05).Conclusion The intrave-nous injection of iodixanol can reduce the occurrence of acute adverse reaction ,will not increase the incidence of CIN . It can be used safely .

Objective To investigate the computed tomography (CT) features of solitary nodular invasive mucinous lung adenocarcinoma (IMA) in stage IA and establish its prediction model. Methods We included 53 lesions of 53 patients with stage-IA IMA and 141 control lesions of 141 patients with invasive non-mucinous lung adenocarcinoma (NIMA) that were confirmed by surgical pathology in our hospital from January 2017 to December 2019. Univariable analysis was used to compare the demographics and CT signs of the two groups. Multivariable logistic regression analysis was performed to determine the main factors influencing solitary nodular IMA. A risk score prediction model was constructed based on the regression coefficients of the main influencing factors. A receiver operating characteristic (ROC) curve was used to assess the performance of the model. Results The univariable analysis showed significant differences between the two groups in age, largest nodule diameter, tumor-lung interface, lobulation, spiculation, air-bronchogram or vacuole sign, vessel abnormalities (P < 0.05). The spiculation sign was different between the two groups, which was longer and softer in the IMA group while shorter and harder in the NIMA group. There was no significant difference in sex, nodule shape, or pleural retraction (P > 0.05), but irregular shapes were slightly more frequent in the IMA group. The multivariable logistic regression analysis showed that obscure tumor-lung interface (odds ratio (OR = 20.930, P < 0.05), air-bronchogram or vacuole sign (OR = 7.126, P < 0.05), spiculation sign (OR = 4.207, P < 0.05), and vessel abnormalities (OR = 0.147, P < 0.05) were the main influencing factors. The prediction model based on those factors’ regression coefficients had an area under the ROC curve of 0.829 (P < 0.05). Conclusion Compared with those with NIMA, patients with solitary nodular IMA in stage IA were older and more likely to have the CT features of obscure tumor-lung interface, air-bronchogram or vacuole sign, and longer and softer spiculation. Based on the regression coefficients of tumor-lung interface, air-bronchogram or vacuole sign, spiculation, and vessel abnormalities, the risk score prediction model showed good predictive performance for solitary nodular IMA.