Objective To explore the application of 18F-FDG PET/CT combined with high-resolution CT (HRCT) in the same scanner on diagnosis of lung cancer, and its influencing factors. Methods 50 patients, in which some cannot supply HRCT raw date and under highly suspicion of being lung cancer, some were postoperative lung cancer and metastasis of lung cancer, were examined by 18F-FDG PET/CT combined with HRCT in the same scanner. Results 50 patients were all successful (100%) on PET/CT scans after preparation, injection, rest and breathing exercises;46 cases (92%) were successful on PET/CT combined with HRCT scans;4 cases (8%) failed on HRCT scans. Ma-lignant lesions were found in 35 cases, with the metastasis of 21 cases;4 in 6 cases of postoperative lung cancer were found metastasis;9 cases of benign pulmonary nodules need to be observed sequentially. Conclusion 18F-FDG PET/CT combined with HRCT in the same scan-ner is valuable on diagnosis of lung cancer. The diagnostic accuracy and sensitivity significantly increase. It is a non-invasive new imaging technology and systemic metastasis can be observed.

Objective To differentiate cerebral parenchymal hemorrhage from contrast extravasation based on the imaging characteristics of a high-density shadow within the brain parenchyma,which is demonstrated on early(within 24 hours)plain CT scan in patients with acute ischemic stroke after receiving mechanical thrombectomy(MT).Methods The clinical data of 77 patients with ischemic stroke caused by acute large-vessel occlusion,who received MT and whose early plain CT scan(performed within 24 hours after MT)showed a high-density shadow within the brain parenchyma,were retrospectively analyzed.According to the results of CT reexamination performed at 24-48 hours after treatment,the patients were divided into parenchymal hemorrhage group(n=38,43 sites)and pure contrast extravasation group(n=39,47 sites).The direct signs(including location distribution,maximum CT value,volume,mixed density sign)and the indirect signs(including local space-occupying effect,intraventricular high density,subarachnoid high density)of the post-thrombectomy intraparenchymal high-density(PTIH)shadow displayed on early CT images after MT were analyzed.The differences in imaging characteristics between the two groups were analyzed by using t-test,Mann-Whitney rank sum test,chi-square test,Fisher exact test and multivariate logistic regression analysis.Results The space-occupying effect(28/38 versus 9/39,P=0.003)and intraventricular high density lesion(5/38 versus 0/39,P=0.025)were more likely to occur in the parenchymal hemorrhage group than in the pure contrast extravasation group.The newly-developed 90 PTIH lesions included 43 parenchymal hemorrhage foci and 47 contrast extravasation foci.Multivariate logistic regression analysis showed that the differences in the PTIH volume and mixed density sign between the two groups were statistically significant(both P＜0.05,OR=2.93 and OR=9.24 respectively).The optimal critical value of PTIH volume for diagnosing cerebral parenchymal hemorrhage was 9.3 cm3.Conclusion The space-occupying effect and intraventricular high density are the indirect signs for judging a newly-developed PTIH to be a cerebral parenchymal hemorrhage.PTIH volume ≥9.3 cm3 and mixed density sign are the direct signs for judging a newly-developed PTIH to be a cerebral parenchymal hemorrhage.