Objective:To investigate the effect of different acquisition duration of brain image of 18F-florbetaben(18F-FBB)positron emission tomography(PET)on standardized uptake value(SUV).Methods:Eight subjects who underwent 18F-FBB PET examination in Chinese PLA General Hospital from May 2021 to June 2021 were selected,including 5 persons of healthy control and 3 patients with mild cognitive impairment(MCI).All subjects underwent 18F-FBB PET imaging,and the dynamic PET images of them on brains were continuously acquired for 20 min between 90 and 110 min after the 18F-FBB injection was injected as(3.7-5.5 MBq/kg).Under the situation that other reconstruction parameters did not change,the images were reconstructed at 0-1,0-3,0-5,0-10,0-15 and 0-20 min,respectively.The same of region of interest(ROI)ranges were delineated in bilateral frontal cortex,bilateral temporal cortex,bilateral parietal cortex,posterior cingulate gyrus and cerebellar cortex of each group of images.And then,the corresponding mean standardized uptake value(SUVmean)of each region was obtained.The differences of SUVmean values of different ROI values between each group of data images and the images of 0-20 min were compared and analyzed.Results:There were significant differences in SUVmean between the acquired images in 0-1,0-3,0-5 and 0-10 min and the acquired standard images of 0-20 min(t=-7.569--2.410,P<0.05),respectively.There were no significant differences in SUVmean between the acquired images of 0-15 min and the acquired standard images of 0-20 min in the bilateral frontal lobe,bilateral temporal lobe,bilateral parietal cortex and posterior cingulate gyrus(P>0.05),only there was significant difference in the cerebellar cortex area between them(t=-5.597,P<0.001).Conclusion:The results of 15 min can reach to the similar results of 20 min in acquiring images,which can shorten the time of examination,and enhance the degrees of comfort and cooperation of patients in examination.It has clinical application value.

Objective:To construct a prediction model for ventilator-associated pneumonia (VAP) in mechanically ventilated preterm infants in the neonatal intensive care unit (NICU) and to test its clinical effect.Methods:This was a cross-sectional study. A total of 740 preterm infants admitted to the NICU for mechanical ventilation from July 2018 to June 2023 were retrospectively selected as the study subjects, and were divided into the modeling set (518 cases) and the validation set (222 cases) according to the ratio of 7∶3 using the computer-generated random number method. The modeling set was divided into the VAP group (181 cases) and the non-VAP group (337 cases) according to whether VAP occured, and 21 clinical characteristics were analyzed, using single factor difference analysis to screen predictive factors, the independent risk factors of VAP in mechanically ventilated preterm infants were determined by multivariate Logistic regression analysis, and the nomogram model was made by R software. Then, the nomogram model was tested by validating the data of the validation set. The receiver operating characteristic (ROC) curve, Hosmer-Lemeshow goodness-of-fit test, calibration curve and clinical decision curve were used to evaluate the efficacy and practical value of the model.Results:There were 88 males and 93 females in the VAP group, with 156 cases of gestational age<34 weeks and 25 cases of gestational age≥34 weeks. There were 155 males and 182 females in the non-VAP group, with 196 cases of gestational age<34 weeks and 141 cases of gestational age≥34 weeks. Birth weight ( OR=0.114, 95% CI 0.044-0.268, P<0.05) and oral care of breast milk ( OR=0.124, 95% CI 0.0.057-0.249, P<0.05) were protective factors for VAP in mechanically ventilated preterm infants, and Apgar score at 5 min after birth ( OR=2.895, 95% CI 1.318-6.419, P<0.05), serum prealbumin at 72 h of mechanical ventilation ( OR=4.837, 95% CI 2.643-9.063, P<0.05), gastric contents reflux ( OR=6.754, 95% CI 3.156-15.240, P<0.05), and time of mechanical ventilation ( OR=7.784, 95% CI 3.491-18.160, P<0.05) were independent risk factors for VAP in mechanically ventilated preterm infants. The area under the curve (AUC) of the ROC curve of the modeling set was 0.929 (95% CI 0.907-0.950, P<0.01), and the validation set (AUC) was 0.917 (95% CI 0.882-0.952, P<0.01), the model has good discrimination. The C indices of the modeling set and the validation set were 0.93 and 0.92 respectively by sampling 500 times by the Bootstrap method, indicating that the model had good consistency, and the decision curve suggested that the prediction model was far from the extreme curve and the net return value was high, indicating that the nomogram prediction model constructed this time had high prediction value. Conclusions:Birth weight, Apgar score at 5 min after birth, time of mechanical ventilation, oral care of breast milk, serum prealbumin at 72 h of mechanical ventilation, and gastric contents reflux are independent influencing factors for VAP in mechanically ventilated preterm infants. The nomogram prediction model constructed can provide a visual and simple evaluation tool for early identification of high-risk children and reducing the occurrence of VAP.

Objective:To investigate the effects of apolipoprotein E (APOE) ε4 allele on β-amyloid (Aβ) deposition in subcortical structures and functional connectivity (FC) between brain regions in patients with Alzheimer′s disease (AD). Methods:Forty-three patients with probable mild/moderate AD were prospectively enrolled from the First Medical Centre, Chinese PLA General Hospital between January 2023 and October 2023, including 23 APOE ε4+ patients (12 males and 11 females, age (74.8±8.4) years), 20 APOE ε4- patients (14 males and 6 females, age (77.6±8.9) years) and 20 normal cognitive volunteers (NC) (15 males and 5 females, age (75.3±6.2) years). All subjects underwent 11C-Pittsburgh compound B (PIB) PET/MR brain imaging. The differences of gray matter volume (GMV) in subcortical structures (hippocampus, amygdala) among the three groups were analyzed by one-way analysis of variance and least significant difference (LSD) t test. Independent-sample t test and Pearson correlation analysis were used to analyze difference in Aβ deposition between APOE ε4+ patients and APOE ε4- patients, and the correlation between subcortical structure and brain FC. Results:The GMV of bilateral amygdala between NC group and APOE ε4+ gene carrier group, and between APOE ε4+ and APOE ε4- gene carrier groups were significantly different ( F=6.43, P=0.002; P values: 0.002, 0.003). Significant difference of GMV was observed in the bilateral hippocampus among three groups ( F=5.34, P=0.030). Abnormal PIB uptake was detected in both the hippocampus and amygdala of both APOE ε4+ and APOE ε4- gene carrier groups, with a more pronounced effect observed in the APOE ε4+ group ( t values: 3.14, 2.19, P values: 0.032, 0.009). Taking the hippocampus as the seed point, there was no obvious abnormality in the whole brain connectivity map among APOE ε4+, APOE ε4- carriers and NC groups. With the amygdala as the seed point, the whole brain connectivity in the APOE ε4+ gene carrier group was significantly reduced, and the connectivity between the amygdala and the cingulate gyrus, parietal lobe and temporal lobe was significantly reduced in the APOE ε4+ gene carrier group compared with NC group, while the connectivity between the amygdala and the whole brain was not significantly reduced in the APOE ε4- gene carrier group. Aβ deposition in amygdala was positively correlated with FC coefficients of frontal brain regions, gyrus rectus, right middle occipital gyrus and left temporal lobe ( r values: 0.56-0.70, all P<0.05). Conclusion:APOE influences GMV and Aβ deposition of hippocampus and amygdala, and FC of amygdala, and may be involved in the pathological mechanism of cognitive impairment.

Objective:To compare the accuracy of visual qualitative assessment and semi-quantitative analysis for 18F-florbetaben ( 18F-FBB) β-amyloid (Aβ) imaging in the diagnosis of Alzheimer′s disease (AD) and to explore their clinical application value. Methods:From January 2019 to October 2019, 17 patients (8 males, 9 females, age (74.1±8.5) years) with mild/moderate-stage clinically probable AD and 17 cognitive normal control (NC; 9 males, 8 females, age (64.5±6.3) years) were prospectively enrolled in this study. All patients underwent dynamic 18F-FBB PET/CT brain imaging in the Chinese PLA General Hospital. Visual qualitative assessment and semi-quantitative analysis methods were used to analyze PET brain imaging results. The difference of standardized uptake value ratio (SUVR) between the two methods was analyzed by using independent sample t test. The consistency of the two methods and clinical results was analyzed by Kappa test. The cut-off value of SUVR for the diagnosis of AD was determined by receiver operating characteristic (ROC) curve. Results:The sensitivity, specificity and accuracy of visual qualitative assessment to diagnose AD were 14/17, 16/17 and 88.2% (30/34). The global SUVR of NC and AD group were 1.09±0.85 and 1.75±0.25 ( t=-10.263, P<0.001), and the composite SUVR were 1.16±0.57 and 1.89±0.15 ( t=-10.789, P<0.001), respectively. The cut-off value of SUVR for the diagnosis of AD was 1.47, with the sensitivity of 15/17, the specificity of 16/17 and the accuracy of 91.2%(31/34). The visual qualitative assessment and semi-quantitative analysis had good consistency with clinical diagnosis results with Kappa value of 0.765 and 0.824 respectively (both P<0.001). Conclusion:The visual qualitative assessment and semi-quantitative analysis methods used in 18F-FBB Aβ imaging to diagnose AD patients show high accuracy and can provide effective value for clinical diagnosis, but the visual qualitative assessment method is concise and easy to grasp, which is worth further promotion and use in clinical.

Objective Based on the data of scientific research output in a top three hospital in Beijing from 2015 and 2016,stochastic frontier analysis is conducted to estimate the efficiency of scientific research performance in different departments of this hospital,so as to draw the impetus for the growth of departments.Methods According to the results of the stochastic frontier model,comprehensive analysis and evaluation are conducted for the research performance of various departments.Results The overall average technical efficiency of the hospital is 0.44,and improvement space for the technical efficiency of scientific research performance is still 0.56.There are significant differences in the technical efficiency of each department.Among the four major categories,the D section is higher than the technical efficiency of class A,B and C departments.Conclusions The overall technical efficiency of the hospital is not high,the level of scientific research output of the four types of departments is not balanced,which should be emphasized in the improvement of scientific research performance level.

Objective Discussion on the methods of retrospectively selecting peer review experts based on the results of review.Methods Based on the review data of peer reviewers,peer review experts are retrospectively selected based on the voting,rating and comprehensive evaluations,as well as their variations and errors during the review.Results Through the retrospective selection of peer reviewers,there is a better convergence of reviews,which assures the quality of future peer reviews.This method is superior to the prospective selection of peer reviewers.Conclusions Based on the results of the review,retrospective selection of peer review experts is feasible and helpful for the selection of high-level peer review experts,which can improve the quality of peer review and standardize peer review.

Objective To study the dynamic changes of scientific research efficiency of 51 departments in a top three hospitals in Beijing from 2014 to 2016,and to provide reference information for improving the efficiency of scientific research in hospital departments.Methods The CCC model of DEA,BCC model were used for lateral analysis,and then Malmquist index was used for longitudinal analysis.Results There were 12 (23.53％) departments in 2014,11 (21.57％) departments in 2015,9 (17.65％) departments in 2016 data envelopment analysis was valid,from 2014 to 2016,41 (80.39％) departments of the hospital increased the total factor productivity.Conclusions The total factor productivity of the 51 departments in the hospital increased from 2014 to 2016,and technological progress was the main reason for its growth.

Objective Based on the three years' peer review data of a project fund,the results of fund peer review were analyzed and evaluated,to provide references for further improvement of the peer review and management.Methods Based on the fund's peer review results of 2145 projects in three years,descriptive statistics,single-item identification index were adopted,as well as RJ normality test,t-test and other statistical methods,to analyze and assess the overall data of fund,project categories,individual scores,etc.Results The score distribution of the three year peer review project of the fund is almost normal distribution,and the overall consistency of peer review shows a better trend.The analysis shows that the peer review experts of the fund have better consistency in terms of project innovation,rationality and characteristics.While there were differences in the peer review of applicability.Conclusions The three year peer review data of the fund show that three years' evaluation results are reliable,reasonable,and the quality of evaluation is good,showing a better development trend in both project quality and expert consistency.

Objective To explore different clinical and pathological features of thymomas with and without myasthenia gravis(MG),and accumulate the experience of perioperative managements.Methods Patients with thymoma admitted by our department between June 2010 and June 2016,were retrospectively reviewed.Results Of the 273 patieuts,150 were males and 143 were fenales(median age:48 years).115 of all patients(42.1％) were combined with paraneoplastic diseases.There was no mortality during perioperative period.Video-assisted Thoracoscopic surgery was successfully performed for 246 cases(90.1％).The female thymoma patients with with MG(TMG) were more than those without MG and thymic hyperplasia (53.0％ VS 39.5％,P =0.036).Compared to the thymoma patients without MG and thymic hyperplasia,the TMG was associated with younger age of onset [(46.6 ± 12.9) years VS.(50.6 ± 14.32) years,P =0.026],longer hospital stay [(18.3 ± 9.4)days VS.(14.6 ±5.7) days,P =0.000],higher postoperative complications morbidity(22.0％ VS.11.6％,P =0.027).Although the TMG has a lower recurrence rate,there was no significant difference between the two groups for recurrence rate(0 VS.2％,P =0.274).Conclusion Extended thymectomy should be recommended for thymoma and thymic hyperplasia whether combined with or without paraneoplastic diseases.