Current situation and cost-effectiveness of 18F-FDG PET/CT for the diagnosis of fever of unknown origin and inflammation of unknown origin: A single-center, large-sample study from China.

PURPOSE: 18F-FDG PET/CT has an important role in the evaluation of fever of unknown origin (FUO) and inflammation of unknown origin (IUO). Our study was to investigate the current status of the inclusion of 18F-FDG PET/CT within FUO/ IUO diagnostic work-up and evaluate the cost-effectiveness of it in China. METHODS: A total of 741 FUO/IUO patients admitted to our hospital from January 2012 to December 2019 were retrospectively reviewed. The clinical characteristic, medical expenses to reach diagnosis and the proportion of definite etiological diagnosis achieved upon hospital discharge were compared between patients examined by 18F-FDG PET/CT (18F-FDG PET/CT group) and patients not examined by 18F-FDG PET/CT (non-18F-FDG PET/CT group). RESULTS: The mean age, proportion of critically-ill patients, proportion of rheumatologic diseases, the number of examinations and hospitalisation days to reach diagnosis in the 18F-FDG PET/CT group were significantly higher than those in the non-18F-FDG PET/CT group. The mean medical costs of 18F-FDG PET/CT group were significantly higher than those of non-18F-FDG PET/CT group, whereas the proportion of definite etiological diagnosis achieved upon hospital discharge of 18F-FDG PET/CT group was significantly higher than that of non-18F-FDG PET/CT group. The mean hospitalisation days and mean medical costs before diagnosis were significantly lower in patients who undertook 18F-FDG PET/CT ≤ 7 days after hospital admission than those in patients who undertook 18F-FDG PET/CT > 7 days after hospital admission. CONCLUSIONS: 18F-FDG PET/CT is mostly used in critically-ill and hard-to-diagnose FUO/IUO patients currently in China, which may conceal its cost-effective advantage. While the early use of 18F-FDG PET/CT according to patient characteristics and etiological clues could help to reduce hospitalization stay, limit medical costs, thus producing its diagnostic effect to the great extent.

Diffuse pulmonary metastases with negative ¹8FDG positron emission tomography/computed tomography and positive post-radioiodine therapy scan of papillary thyroid cancer.

A female papillary thyroid cancer patient with diffuse micronodular pulmonary metastases was confirmed only by post radioactive iodine (RAI) therapy whole body scan (RxWBS). Her diagnostic iodine-131 whole body scan (DxWBS), chest CT and 18FDG PET/CT scan were all negative. Attention and pitfalls of this case concerning surgical and RAI dose management are against current international guidelines on thyroid cancer.

[Murine model of Graves disease induced by thyroid-stimulating hormone receptor gene transfected via liposome].

OBJECTIVE: To compare the efficacy of different expression vectors, target genes, and immunization procedures in transfecting mice via liposome to construct murine model of Graves disease. METHODS: We linked pCDNA3.1(+) and pUBC to full-length human TSHR and TSHR A subunit cDNA to yield four plasmids, which were later injected intramascularly or subcutaneously into female Balb/c mice via liposome. The blood anti-TSHR antibody (TRAb) were determined and the body weight were measured after each immunization. Serum thyroid hormone levels were measured after the animals were sacrificed. RESULTS: In mice immunized with pUBC, no significant variance with control in weight nor serum TRAb concentration was observed. Weight gain in pCDNA3.1(+) group was significantlyly slower than controls (p<0.05), and serum TRAb concentration was also significantly elevated. In pCDNA group, animals immunized with TSHR A subunit (TSHRA subgroup) as the target gene revealed even significantly slower weight gain (p<0.001) and even faster TRAb elevation than those immunized with full length TSHR. Significantly higher FT4 (p=0.023) was observed in TSHRA and TSHR subgroups, which was reversely correlated to weight gain, but no significant difference (p>0.05) in FT3 was observed. Weight gain and TRAb concentration mainly varied in the later period of immunization. CONCLUSIONS: Immunization with pCDNA3.1(+) and TSHR A subunit gene together with higher immunization frequency increases the chance of model induction. Furthermore, FT4 is a better indicator for assessing the thyroid function in this model.