[Experimental comparison of temporal bone imaging protocol optimization between 10 µm otology CT and multi-slice CT].

Objective: To evaluate different protocol optimization strategies for temporal bone between10 µm otology CT and multi-slice CT (MSCT). Methods: Ten adult skull specimens (20-sides temporal bones) were prospectively enrolled. From October to November 2020, the temporal bones were scanned under four different imaging conditions using 10 µm otology CT (90 kV, 120 mAs; 90 kV, 140 mAs; 100 kV, 120 mAs; 100 kV, 140 mAs) and MSCT (120 kV, 220 mAs; 120 kV, 310 mAs; 140 kV, 160 mAs; 140 kV, 220 mAs), respectively. The image quality was subjectively scored using 5-grade scores, and the contrast noise ratio (CNR) of the image was measured. The absorbed dose of tissues and organs under different imaging conditions was measured by thermoluminescence dosimeter, and the effective dose was calculated. The figure of merit (FOM) is defined as the ratio of the square of the mean CNR to the effective dose. χ2 test was used to compare the difference of subjective scores of different scanning parameter groups, and paired t test was used to analyze and compare the difference of image CNR of different scanning parameter groups. The image quality, radiation dose and FOM of the combination of recommended parameters of the two devices were analyzed and compared. Results: For 10 µm otology CT, under 100 kV condition, the CNR of 140 mAs group was better than that of 120 mAs group (11.27±1.85 vs 10.26±1.38, P<0.001). There was no significant difference in subjective scores between the two groups [5.00 (4.00, 5.00) vs 5.00 (4.25, 5.00), P=0.264]. For MSCT, under 120 kV condition, the subjective scores and CNR of 310 mAs group were better than those of 220 mAs at 120 kV [4.00(3.00, 4.00) vs 3.00(3.00, 3.00),P=0.002;5.24±0.62 vs 4.60±0.62,P<0.001]. According to the principle of image quality-radiation dose optimization, the combination of 100 kV with 120 mAs and 120 kV with 310 mAs are recommended for 10 µm otology CT and MSCT, respectively. The subjective scores and CNR of 10 µm otology CT images were better than those of MSCT (5.00 (4.25, 5.00) vs 4.00 (3.00, 4.00), 10.26±1.38 vs 5.48±0.22, P<0.001). The effective dose was 1/3 of that of MSCT (82.99 µSv vs 252.56 µSv), and the FOM was 11.16 times of that of MSCT (1 268.44 mSv-1 vs 113.71 mSv-1). Conclusion: The temporal bone image quality of newly developed 10 µm otology CT is significantly better than that of MSCT, and its effective dose is lower than that of MSCT, which has more accurate and safer application potential.

Effect of LGR4 on synovial cells and inflammatory factors in rats with traumatic osteoarthritis.

OBJECTIVE: Traumatic arthritis is one of the most common diseases in orthopedics. LGR4 is involved in bone formation and bone development. However, the role of LGR4 in synovial cells of rats with traumatic osteoarthritis has not been reported. MATERIALS AND METHODS: Sprague Dawley (SD) rats were randomly divided into the control group and model group. The Real Time-Polymerase Chain Reaction (RT-PCR), Western blot, and Enzyme-Linked Immunosorbent Assay (ELISA) were used to analyze the expression of LGR4 in synovial tissue and synovial fluid. Synovial cells were isolated and cultured, followed by transfection of LGR4-pcDNA3.1 plasmid into cells. Cell proliferation was analyzed by MTT and EdU assay, and the Caspase-3 activity was assessed using the Caspase-3 activity kit. The secretion of the inflammatory factors interleukin-1 (IL-1), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) was detected by ELISA. NF-κB signaling pathway changes were evaluated by the Western blot. RESULTS: In the model group, LGR4 mRNA expression in synovial tissue was significantly decreased, and the secretion of LGR4 in the synovial fluid was significantly decreased compared with the control group (p<0.05). LGR4 protein expression in the synovial membrane in the model group tissue was reduced. The transfection of LGR4-pcDNA3.1 plasmid into synovial cells promoted the LGR4 expression, inhibited the proliferation of synoviocytes, increased the Caspase-3 activity, the secretion of IL-1, TNF-α, and IL-6, as well as the decreased expression of NF-κB with a statistical significance, compared with the control group (p<0.05). CONCLUSIONS: LGR4 expression is reduced in the rat model of traumatic osteoarthritis. The upregulation of LGR4 expression can inhibit the secretion of the inflammatory factors and inhibit the proliferation of the synovial cells by regulating NF-κB signaling pathway, which may alleviate the development of the joint inflammation.