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Objective:To explore the effectiveness of deep learning image reconstruction (DLIR) algorithm compared to adaptive statistical iterative reconstruction (ASIR-V) algorithm in improving the quality of low-dose brain CT images.Methods:Retrospective inclusion of patients who underwent brain CT examination in the People's Liberation Army General Hospital from November 2021 to August 2022. Four different algorithms were used to reconstruct low-dose CT scans of all patients to obtain 30% intensity ASIR-V (ASIR-V-30%) images, low intensity DLIR (DLIR-L) images, medium intensity DLIR (DLIR-M) images, and high intensity DLIR (DLIR-H) images. The regions of interest were selected from four sets of images, including superficial white matter, superficial gray matter, deep white matter, and deep gray matter, and their CT values and standard deviations were measured for calculating signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR).Subjective evaluation of image quality was conducted by three neuroimaging physicians based on the Likert 5-component scale. The objective and subjective scores of the 4 groups of images were analyzed using ANOVA or Kruskal Wallis. If there are overall differences, pairwise comparisons were conducted within the group.Results:A total of 109 patients were enrolled, including 104 males and 5 females, aged 65-110 years (89.16 ± 9.53) years. The radiation exposure of brain CT low-dose scanning was (0.93 ± 0.01)mSv, significantly lower than that of conventional scanning (2.92 ± 0.01) mSv ( t = 56.15, P < 0.05). The differences in objective image quality analysis of ASIR-V-30%, DLIR-L, DLIR-M, and DLIR-H images of low-dose CT in SNR deep gray matter, SNR deep white matter, SNR superficial gray matter, SNR superficial white matter, CNR deep gray white matter, and CNR superficial gray white matter were statistically significant( F =98.23, 72.95, 68.43, 58.24, 241.13, 289.91, P < 0.05). Among them, DLIR-H images had the lowest noise in deep gray matter, deep white matter, superficial gray matter, and superficial white matter, and had statistically significant differences compared to other image groups ( t = 167.43, 275.46, 182.32, 361.54, P < 0.05). The subjective score of DLIR-H image quality was superior to ASIR-V-30%, DLIR-L, and DLIR-M, with the statistically significant difference ( t = 7.25, 8.32, 9.63, P < 0.05). Conclusions:Compared with ASIR-V, DLIR algorithm can effectively reduce image noise and artifacts in low-dose brain CT, and improve SNR and CNR. The subjective and objective image quality evaluation of DLIR-H is the best.

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<p><b>OBJECTIVE</b>To evaluate the diagnostic efficacy of IFIR-FIESTA technique in detecting renal artery stenosis in elderly patients.</p><p><b>METHODS</b>Twenty-seven aged patients underwent both IFIR-FIESTA and 3D CE-MRA examinations. The imaging quality and renal artery stenosis grades were evaluated. Kappa test was used to assess the consistency between the two methods. With CE-MRA as the reference, the diagnostic sensitivity, specificity, accuracy, PPV and NPV for IFIR-FIESTA were calculated in detecting renal artery stenosis.</p><p><b>RESULTS</b>The images by the two methods were 100% qualified for diagnosis, although the image quality of CE-MRA was significantly better. IFIR-FIESTA and CE-MRA showed excellent consistency in detecting renal artery stenosis. With CE-MRA as the reference, the diagnostic sensitivity, specificity, accuracy, PPV and NPV for IFIR-FIESTA were 97.1%, 100%, 98.1%, 100%, and 95% in detecting renal artery stenosis, respectively.</p><p><b>CONCLUSION</b>IFIR-FIESTA is feasible as a routine examination for detecting renal artery stenosis in elderly patients.</p>

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Twenty-four patients with parapharyngeal space tumors were treated from 1964 to 1999.There were 11 males and 13 females,ranging in age from 10 to 71 years old.Among 24 patients, benign tumors were 17(70.8%),malignant tumors 7(29.2%).The diagnosis of these tumors were biopsy and CT scaning .Pathologic results showed that the original tumors were salivary gland tissue in 11(45.8%),cranial nerve in 7(29.2%),vascular tissue in 2(8.3%)and the unidentified in 4(16.7%).The surgical approaches for these tumors were neck side incision in 19,through mouth in 5.Results showed that 4 malignant tumors were died in one year,3 cases did not clear;the prognosis of 17 benign tumors were well.