Objective To analyze the value of 18F-fluorodeoxyglucose (FDG) posotron emission tomography/computed tomography (PET/CT) in the detection of relapsing polychondritis (RP) in fever of unknown origin (FUO) patients.Methods Retrospective analysis of the clinical data of 3 patients with FUO,who were final clinical diagnosed as RP,were conducted.Clinical symptoms,laboratory tests and 18F-FDG PET/CT image data were analyzed,and literature were reviewed.Results Three patients with FUO,2 had increased FDG uptake in PET/CT in multiple cartilages,including ear,nose,trachea/bronchial and rib cartilage (SUVmax 2.5-7.5),which were consistent with RP.One case with a history of RP,PET/CT detected pulmonary infla rrmatory lesions which might be the cause of fever.At the same time,PET/CT showed RP presentation in CT with nasal and airway structure changes,but there was no abnormal FDG uptake.Conclusion 18F-FDG PET/CT has an important clinical value in diagnosis and differential diagnosis of RP,and also in follow-up and clinical response observation.

Objective:To further understand the etiological distribution of fever of unknown origin (FUO) in patients underwent 18F-fluorodeoxyglucose (FDG) PET/CT imaging, and to explore the significance of 18F-FDG PET/CT in the diagnosis of different types of diseases in FUO patients. Methods:From January 2013 to August 2019, the clinical and PET/CT image data of 466 FUO patients (194 males, 272 females, age: 3-91(52.7±20.9) years) in Peking University People′s Hospital were retrospectively analyzed. The etiological distribution of FUO patients was analyzed according to the final clinical diagnosis. PET/CT imaging manifestations were analyzed for different types of diseases in FUO patients. The role of 18F-FDG PET/CT in differential diagnosis for FUO was evaluated through clinical questionnaire. Data were analyzed by using χ2 test. Results:The common disease types in FUO patients were rheumatic and immune disease (48.7%, 227/466), infection (28.5%, 133/466) and malignant tumor (11.2%, 52/466). For PET/CT imaging, 95.5% (445/466) of the patients were positive, of which 313 (70.3%, 313/445) were found to have focal lesions, and the other 132 (29.7%, 132/445) showed only nonspecific abnormal uptake. Lesions in different types of diseases were varied in the location, morphological changes as well as FDG uptake. The results of the questionnaire showed that PET/CT imaging could benefit 95.9% (447/466) of the patients in the FUO diagnosis and treatment. PET/CT reached direct etiological diagnosis of malignant tumors more frequently than other types of diseases ( χ2 values: 14.408-25.466, all P<0.001). PET/CT helped or directly reached the etiological diagnosis of rheumatologic diseases more frequently than infection and unknown cause group( χ2 values: 7.922, 9.647, both P<0.05). Conclusion:18F-FDG PET/CT imaging has high clinical value in the diagnosis of FUO etiology and can provide multilevel diagnostic information.

In order to help the standardized residency training of nuclear medicine residents, the standardized residency training base of nuclear medicine residents in Peking University People's Hospital, combined with forty-five nuclear medicine departments of teaching hospital, established the WeChat official account of "Standardized Residency Training of Nuclear Medicine" and submitted one teaching case per week. The appearance of the WeChat official account of "Standardized Residency Training of Nuclear Medicine" has made up for the shortcomings of insufficient teaching cases in a single training base, strengthened the training of residents' imaging diagnostic thinking, and promoted mutual learning among the bases. By writing teaching cases, instructors and residents have opened up ideas, increased knowledge, improved self-learning ability, and cultivated imaging diagnostic thinking. With the flexible and practical features of the WeChat official account, the consciousness and sustainability of residents' learning have been enhanced.

Objective·To explore the expression of sorting nexin 1(SNX1)in colorectal cancer(CRC)and its impact on the proliferation and migration of CRC cells.Methods·Transcriptomic data and clinical pathological information of CRC were obtained from The Cancer Genome Atlas(TCGA),Genotype-Tissue Expression(GTEx),and Gene Expression Omnibus(GEO)databases for enrichment analysis with Gene Set Enrichment Analysis(GSEA)software.The expression of SNX1 in CRC tissues and cells was detected by quantitative real-time polymerase chain reaction(qPCR),Western blotting,and immunohistochemistry staining(IHC).Small interfering RNA(siRNA)was used to knock down the expression of SNX1 to observe its effect on tumor cell proliferation and migration.Correlation analysis was conducted to explore the potential molecular mechanisms underlying SNX1-mediated CRC cell migration,and mRNA level validation was performed in SNX1 knockdown cell lines.Results·Analysis of CRC patients data in TCGA and tissue microarrays revealed that SNX1 expression was downregulated in CRC tissues and correlated with tumor diameter and distant metastasis.Knockdown of SNX1 enhanced tumor cell proliferation and migration.The expression of SNX1 was negatively correlated with metastasis associated in colon cancer 1(MACC1),mesenchymal to epithelial transition factor(MET),and Notch;knockdown of SNX1 led to upregulation of these genes.Silencing SNX1 resulted in the downregulation of the epithelial marker cadherin 1(CDH1)and the upregulation of vimentin(VIM)and Snail family transcriptional repressor 1(SNAI1).Conclusion·SNX1 expression was significantly downregulated in CRC tissues and correlated with patient prognosis.Low expression of SNX1 enhanced the proliferation and migration of CRC cells and was associated with the MACC1-MET pathway and EMT.SNX1 may serve as a potential biomarker for poor prognosis and a novel therapeutic target in CRC.