RESUMO
OBJECTIVE: This study aims to investigate the value of gemstone spectral imaging (GSI) combined with an 80 mm wide-body detector in head-neck CTA. METHODS: Ninety patients with head-neck CTA were prospectively selected and randomly divided into a control group and a test group, with 45 patients in each group. The control group was scanned conventionally. With a tube voltage of 100 kVp and detector width of 40 mm, a 70 ml contrast agent was injected at a flow rate of 5.0 ml/s. The test group used GSI. With a tube current fixed of 445 mAs and a detector width of 80 mm, the contrast agent was injected at a flow rate of 3.5 ml/s and 0.6 ml/kg body weight, and the 55 keV virtual monoenergetic images (VMIs) were automatically reconstructed. Finally, the target vessel CT values, background noise (BN), signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), subjective scores, contrast agent dose, CT dose index volume (CTDIvol), and dose length product (DLP) were recorded. The DLP was converted to the effective dose (ED). RESULTS: The target vessel CT values, BN, SNR, CNR, and subjective scores of the two groups were not statistically significant (all P > 0.05), and the image quality of both groups was the same and met the diagnostic requirements. The contrast agent dose and effective dose (ED) in the test group were approximately 44% and 26% lower than that of the control group, respectively (all P < 0.05). CONCLUSION: In head-neck CTA examination, the Revolution CT GSI combined with an 80 mm wide-body detector can reduce the contrast agent dose and radiation dose while ensuring image quality.
RESUMO
OBJECTIVE: Autophagy is a programmed cell death procedure, which has essential functions in tumorigenesis. However, its temporal expression and function under different status are yet to be determined. This study aims to investigate the temporal expression of autophagy and its possible function in 7,12-dimethylbenz[a]anthracene (DMBA)-induced hamster buccal-pouch cancer model (HBPCM). METHODS: A total of 50 hamster buccal-pouch tumorigenesis models were established by painting DMBA for 4, 8, 10 and 13 weeks. The expression and subcellular localization of LC3, Beclin 1 and Bcl-2 in buccal lesions were evaluated by immunohistochemical staining and Western blotting. DNA damage was observed by immunohistochemical staining of 8-oHdG. The relationship between Beclin 1 and Bcl-2 was analyzed by immunofluorescence colocalization. RESULTS: The expression levels of LC3 and Beclin 1 associated with autophagy in the experimental buccal pouch of HBPCM were significantly upregulated after 4 weeks (P<0.05), but gradually downregulated after 13 weeks of HBPCM induction. By contrast, the expression level of Bcl-2 was significantly upregulated after 13 weeks. The co-localized regions of Bcl-2 and Beclin 1 peaked after 4 weeks and then decreased gradually. The DNA damage in epithelial cells increased slightly after 4 weeks, and then rapidly decreased over the next 2 months. CONCLUSION: Autophagy is motivated by a tumor suppressor that diminishes carcinogen-induced DNA damage. However, autophagy is gradually suppressed, which may be attributed to the interaction between Bcl-2 and Beclin 1. This result indicates that the promotion of autophagy may suppress malignant transformation and provide new insights on future potential treatments of HBPCM.
