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ObjectiveTo investigate the value of reduced field-of-view DWI （r-FOV DWI） in quantitative assessment of axial spondyloarthritis. MethodsA total of 112 patients with chronic back pain or suspected axial spondyloarthritis receiving full field-of-view DWI （f-FOV DWI） and reduced field-of-view DWI （r-FOV DWI） from December 2019 to December 2021 were enrolled. Next， subjective image quality assessment （anatomical detail， artifacts， distortion， overall image quality） and objective image quality assessment including （signal to noise ratio and contrast to noise ratio） were conducted by two experienced radiologists. In addition， the Apparent Diffusion Coefficient （ADC） values of three groups （active group， inactive group， and control group） on the two DWI sequences were measured by the two radiologists， respectively. Finally， the consistency of measurement between the two researchers was evaluated and the differences in ADC values was compared. Results102 patients were included and were divided into three groups， including the active group （n=32）， inactive group （n=29）， and control group （n=41） according to ASAS diagnostic criteria. All subjective and objective image quality metrics were rated in favor of r-FOV DWI images compared with f-FOV DWI images ［overall image quality： DWI 4（3~4） vs. 3（3~3） and SNR： 6.58（5.05~10.38） vs. 4.46（2.37~10.04）， CNR： 2.04（-1.14~8.29） vs. 0.97（-8.19~7.12）；P＜0.05］. Inter-rater consistency of the two researchers were 0.60~0.74. According to the AUC curve， group inactive vs. control showed r-FOV DWI was better than f-FOV DWI. In other groups （lesion vs. control， active vs. inactive）， there were no differences between both sequences（P＜0.05）. ConclusionThe subjective image quality score and signal to noise ratio of r-FOV DWI were higher than those of f-FOV DWI， which could be used for quantitative assessment of axial spondyloarthritis.
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Aim To establish an in vitro fluorescence spectrophotometry based on the end-product malondialdehyde(MDA)for evaluating hydroxyl radical-scavenging ability, and compare the advantages and disadvantages of fluorescence and visible methods.Methods The reaction time, temperature, and the concentration of key reactant deoxyribose were investigated and optimized respectively.Under different solvent conditions, sensitivity and the measurement window of two methods were compared.The hydroxyl radical scavenging ability of tanshinone I was determined by these two methods.Results The optimal temperature and time was 37 °C and 60 min, and the concentration of deoxyribose was 2.8 mmol·L-1.The limit of detection for the fluorescence method(4.49 nmol·L-1)was much lower than that of the visible spectrophotometry(39.15 nmol·L-1).The ratio of model/control(the measurement window)of the fluorescence method was much larger than that of visible spectrophotometry in both the aqueous system and the organic system(containing DMSO).Within the concentrations of 62.5 mg·L-1-1 000 mg·L-1, tanshinone I showed scavenging ability on hydroxyl radicals in a concentration-dependent manner using the fluorescence method, but the visible method could not.Conclusions In contrast to visible method, fluorescence method has the advantages of higher sensitivity and stronger anti-interference ability to the color of test substance and the specificity of solvents.By virtue of large measurement window, it can be applied to evaluating the effect of fat-soluble test substances.