Objective To analyze the CT features of solitary pulmonary nodules(SPN) in patients with malignant tumor with the aim of improving its diagnosis and differential diagnosis in this special background .Methods From May 2014 to De-cember 2018, the CT data of 76 pathologically confirmed SPNs in patients with malignant tumor were retrospectively analyzed . The CT features of SPNs, including density, morphology and change of peripheral lung field and adjacent structures, were mainly analyzed.The characteristics of different types of nodules and their differences were summarized .Results Among the 76 SPNs, there were 41(53.9％) primary lung cancers, 14(18.5％) metastatic tumors, and 21(27.6％) benign lesions(in-cluding 12 inflammatory nodules, 7 tuberculous nodules and 2 benign tumors).Of all nodules, there were 57(75％) solid nodules, including 23(40.4％) primary lung cancers which mainly manifested as nodules with rough margin , close to adjacent vessel and bronchus and usually had internal or edge features(19, 82.6％), 14(24.6％) metastatic tumors which mainly showed as round or oval, homogeneous density, smooth margin nodules(12, 85.7％), and 18(31.6％) inflammatory nodules which mainly showed as lesions with rough and blurred margin accompanied by peripheral patch or fibrosis (14, 77.8％). There were 19(25％) sub-solid nodules, including 18(94.7％) primary lung cancers, which mainly manifested as nodules with heterogeneous density and clear border(14, 77.8％).There was only 1(5.3％) sub-solid inflammatory nodule.Conclu-sion The pathological nature of SPNs in patients with malignant tumors is various .Understanding their CT characteristics is helpful for diagnosing and differentiating and providing useful information for further treatment .

Objective:To investigate the characteristics of thymus in patients with COVID-19, and to analyze the CT features and dynamic changes of thymus.Methods:Data of 241 patients diagnosed with COVID-19 admitted to Chongqing Three Gorges Central Hospital from Jan. to Mar. 2020 were retrospectively analyzed, and 242 consecutive subjects were selected as the control group from Nov. to Dec. 2019. The thymus classification, size, and average CT values between COVID-19 patients and the control group were compared, as well as those among different clinical types for COVID-19 patients, before and after treatment, were analyzed.Results:① The attenuation of the thymus: 64.7% (156/241) complete fatty replacement thymus, 17.8% (43/241) predominantly fatty thymus, 11.2% (27/241) approximately one-half fatty and one-half soft-tissue-attenuation thymus, and 6.2% (15/241) predominantly soft-tissue thymus in COVID-19 patients were found. 48.3% (117/242) complete fatty replacement thymus, 25.6% (62/242) predominantly fatty thymus, 10.3% (25/242) approximately one-half fatty and one-half soft-tissue-attenuation thymus, and 15.7% (38/242) predominantly soft-tissue thymus were found in the control group. Complete fatty replacement thymus was an independent factor affecting COVID-19 in 40 to 59 years old patients ( OR=3.071, P=0.000) . The rate of complete fatty replacement thymus: severe or critical type > common type > mild type. ② Size: There was no statistical difference of the thymus size between COVID-19 patients and the control group ( P>0.05) , no statistical difference among the mild type, common type and severe or critical type ( P>0.05) , no statistical difference between before and after treatment ( P>0.05) , and there was no correlation with treatment duration ( r=0.047, r=0.071) . ③ Density: There was no statistical difference of the CT value of thymus between COVID-19 patients and the control group ( P>0.05) , no statistical difference among the mild, common and severe type ( P>0.05) . One patient had a 17 HU increase in thymus density after treatment, but there was no statistical difference in 78 patients in thymus CT values between before and after treatment ( P>0.05) , and there was no correlation with treatment duration (r=0.013) . Conclusions:COVID-19 patients have a high rate of complete fatty replacement thymus. And the heavier the clinical classification, the higher the rate of complete fatty replacement thymus. Complete fatty replacement thymus is a risk factor for COVID-19 patients in 40 to 59 years old.

Objective:To explore the alteration of structural network, cognitive scores in patients with anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis, as well as the relationship between cognitive impairment and changes of structural networks in patients with NMDAR encephalitis.Methods:This study was a retrospective study. A total of 39 patients with anti-NMDAR encephalitis were recruited as the autoimmune encephalitis group (AE group) from the First Affiliated Hospital of Chongqing Medical University between September 2012 to December 2019, and 32 healthy volunteers with normal results of routine head MR examinations and no history of central nervous system diseases were recruited as the health control group (HC group). There were 16 males and 23 females, aged from 13 to 66 (34±15) years, with duration of disease from 11 to 110 (31±20) days in AE group, and there were 16 males and 23 females, aged from 13 to 66 (34±15) years in HC group. All subjects underwent diffusion tensor imaging (DTI) scan and cognitive function evaluation. The brain structural networks of two groups were constructed by deterministic fiber tracking techniques, and the differences of global topological properties [clustering coefficient (C p), shortest path length (L p), local efficiency (E loc), global efficiency (E glob), normalized C p (γ), normalized L p (λ), small-worldness (σ)] and local topological properties between two groups were analyzed by the graph theory approch. The correlations between characteristics of brain structural networks and cognitive function scores were further analyzed. Results:There was no significant difference in age and gender distribution between the AE group and HC group ( P>0.05). The C p [0.005(0.004, 0.007)], γ (1.76±0.13), λ (0.51±0.03) and σ value (1.57±0.13) of AE group were decreased when compared with HC group [the values were 0.007(0.004,0.017), 2.13±0.63, 0.55±0.06 and 1.73±0.36 each] ( Z=-939.00, t=-3.58, t=-4.16, t=-2.58, P<0.05). Compared with HC group, nodal efficiencies in the left middle frontal gyrus (orbital part), left and right supplementary motor areas, left olfactory cortex, left gyrus rectus, bilateral insula, left postcentral gyrus, left paracentral lobule and right heschl gyrus were changed ( P<0.05). There were five identical hub regions which contains the left middle occipital gyrus, bilateral supplementary motor areas and precuneus in both groups. However, in the AE group, three hub regions of the left middle occipital gyrus and bilateral middle temporal gyrus were reduced, and the left precentral gyrus was increased as hub region. The nodal efficiencies of the left supplementary motor areas ( r=0.393, P=0.013), right supplementary motor areas ( r=0.384, P=0.016) and left paracentral lobule ( r=0.356, P=0.026) were positively correlated with the montreal cognitive assessment scores. Conclusion:The white matter is extensively impaired in anti-NMDAR encephalitis patients and the changes of topological properties in several brain regions are correlated with cognitive decline.