Characteristics of unintentional injuries reported to Shanghai hospitalized injury surveillance system， 2017‒2020 / 上海预防医学

ObjectiveTo analyze the characteristics of hospitalized unintentional injuries and to provide evidence for formulating injury prevention and control strategies. MethodsDescriptive analysis was conducted on injury information of unintentional injury cases reported from 22 monitoring hospitals during 2017 to 2020 by injury surveillance system. The composition ratio index was used to analyze and explore the distribution（population， time and place）of injuries related to different causes. The disease burden was described by the length of hospital stay and hospitalization cost. ResultsA total of 32 716 hospitalized unintentional injury cases were reported from 22 monitoring hospitals. The male to female ratio was 1.18∶1. The majority of males were aged 15‒64 years and the majority of females were aged over 45 years. The top three causes of injuries were falls， traffic-related and blunt injury. Injuries occurred more frequently in July and August. 42.81% of the cases occurred at home. Fracture cases accounted for 75.79%. The median length of hospital stay was 10 days and the median cost was 15 431.50 yuan. The share of both falls and non-motor vehicle accidents increased year by year. ConclusionFalls among elderly people and road traffic injuries are the main causes of hospitalized unintentional injuries， and sharp or blunt instrument injuries are more severe in the male workforce. Considering high direct and indirect economic losses from injuries， steps should to be taken to improve injury surveillance system and to implement injury prevention and control strategies targeted on key groups and key injuries.

Application of a deep machine learning technique for low dose renal CT perfusion / 中华放射医学与防护杂志

Objective To assess the ability of a deep machine learning technique for improving the quality of one-stop renal low dose CTP images.Methods Twenty-one cases who underwent renal noncontrast CT,triple-phase contrast enhanced CT,and CT perfusion (CTP) were collected prospectively.Revolution CT scanner was used with the scan protocol as followed:120 kVp,20 mA for CTP and 100 mA for triple-phase conctrast enhancement,axial scan,ASIR-V80％,rotation 0.5 s,coverage area for z-axial 160 mm,thickness 5 mm.A total of 15 phases were obtained for the first 28 s and then scanned once at 39,43,47,51,63,83,113,213,353,593 s for CTP,which the phases at the 22,51 and 153 s were the cortical phase,medullary phase and excretory phase,respectively.All CTP data was reconstructed with a deep machine learning technique pixel shine A7 model.The data before and after reconstruction was in group A and in group B,respectively.Compared the all data of cortex in the cortical phase and CTP parameters between the two groups.Results There were significant differences of CT values of SD of cortex (9.04 ± 1.77 and 5.75 ± 1.00,respectively),CT values of SD of elector spinae (8.52 ±2.28 and 5.67 ±0.98,respectively),CNR(16.28 ±6.61 and 28.90 ±1.50,respectively) and SNR (21.41 ± 6.67 and 30.65 ± 7.67,respectively) between the two groups (t=1.562,6.286,5.925,-5.892,-17.274,P＜0.05).The SD of images after PS-B was lower than that before PS-B significantly and SNR was improved obviously.There were no differences of cortical blood flow (BF),blood volume (BV),time to peak (TP) and medullary permeability of surface (PS) between the two groups (P ＞ 0.05).Conclusions The reconstruction of deep machine learning PixelShine technique PS-A7 can reduce the noise of images obtained with low tube current,improve the SNR and can not effect the CTP parameters.

Influence on image quality in low-dose colonography with adaptive statistical iterative reconstruction algorithm / 中华放射医学与防护杂志

Objective To evaluate the feasibility of adaptive statistical iterative reconstruction-V (ASIR-V) to improve image quality in low-dose CT colonography.Methods A series of thirty artificial polyps were established by ligation in an isolated segment of porcine colon.Volume data was acquired on Revolution CT scanner (GE,USA) with High Definition scan mode and different scan parameter combinations:120 kVp with different mAs (10,30,50,70,90,100,120,140,160,180,200,220,240,260,respectively).Images were reconstructed with six different ASIR-V levels of 0 (filtered back projection,FBP),10％,30％,50％,70％ and 90％.Two radiologists were blinded to measure and analyze the objective data independently,including image noise (SD),signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR).The kappa test was used to assess interobserver agreement in subjective image quality score.ICC test was used to examine the consistency of the measurements between two observers.SD,SNR,CNR were performed for statistical analysis in different tube current and different levels of ASIR-V using variance analysis (ANOVA).Results Interobserver agreement for subjective image quality score was good with a kappa value of 0.683.The variation of the tube current(r =0.734,P =0.000) and ASIR-V level(r =0.220,P =0.044) is related to the subjective score of image quality.Under the condition of the same tube current,image quality score of 50％ ASIR-V reconstruction was the highest.Two objective data consistency is good.The differences of image noise (F =423.58,P ＜ 0.05),SNRs(F =124.26,P ＜ 0.05) and CNRs (F =1 030.17,P ＜ 0.05) of different tube current and different levels of ASIR-V reconstruction were statistically significant.In the same tube current,with increased levels of ASIR-V,image noise reduced,CNRs increased.Only in 10,120,140,160,220,240,260 mA,the differences of SNRs were statistically significant(F =8.75-31.36,P ＜ 0.05).For the same level of ASIR-V reconstruction,with the increase of tube current,the image noise decreased,SNR and CNR increased gradually.Conclusions In the CT colonography,the application of ASIR-V algorithm can significantly reduce the noise and enhance the image contrast noise ratio and improve image quality.ASIR-V algorithm with 50％ has better performance in reducing CT image noise.

PixelShine Algorithm in Enhancing the Quality of Reconstructed Abdominal Arterial Phase CT Image / 中国医学影像学杂志

Purpose To explore the feasibility of denoising algorithm-PixelShine algorithm based on deep learning to enhance the quality of abdominal arterial phase CT images rebuilt by 70 kVp combined with adaptive statistical iterative reconstruction-Veo (ASiR-V). Materials and Methods Abdominal arterial phase images of 33 patients [body mass index (BMI) BMI≤20 kg/m2] scanned by GE Revolution CT were retrospectively analyzed (group A) using 70 kVp tube voltage and 50% ASiR-V technique. PixelShine algorithm B2 mode was applied to post-process group A images to obtain PixelShine image (group B). Two observers rated the image quality of the two groups via a 5-point rating system. The consistency of the rating was analyzed. The difference in ratings, noise, virtual signal-to-noise ratio (SNR) of liver and pancreas and contrast noise ratio (CNR) were compared between the two groups of images. Results The image quality rating of group A and B were(3.12±0.33) scores and(3.97±0.53) scores respectively,noise value(14.50±1.42)HU vs(10.05±1.80)HU, liver virtual SNR 4.51±0.53 vs 6.78.±1.27,liver virtual CNR 0.89±0.55 vs 1.42±0.81,pancreatic virtual SNR 9.51±1.69 vs 13.87±3.26, and pancreatic virtual CNR 5.83±1.66 vs 8.48±2.46.The quality rating of images,liver and pancreas virtual SNR,CNR in group B were all higher than those in group A, and the image noise of group B decreased about 31% compared with that of group A, the difference was statistically significant (P<0.05). Conclusion Post-processing with PixelShine algorithm can improve the image quality of 70 kVp abdominal arterial phase, significantly reduce image noise, and increase image SNR and CNR.

Impact of pixel shine algorithm based on deep machine learning on image quality of abdominal low-dose plain CT scanning in patients with high body mass index / 中国医学影像技术

Objective To investigate the impact of deep machine learning Pixel Shine (PS) algorithm on image quality of abdominal low-dose plain CT scanning in BMI≥25 kg/m2 patients.Methods A total of 59 patients (BMI≥25 kg/m2) who underwent abdominal CT scan were collected.The patients were divided into group A (100 kVp,n=30) and B (120 kVp,n=29) according to the tube voltage.According to different reconstruction algorithms and treatment methods,patients in group A were divided into A1 (FBP),A2 (FBP+PS),A3 (50％ASiR-V) and A4 (50％ASiR-V+PS) subgroups,while in group B were divided into B1 (FBP) and B2 (50％ASiR-V) subgroups.CT and SD values of right hepatic lobe and right erector spinae were measured,then SNR and CNR of liver and CT dose index of volume (CTDIvol) were calculated.The consistency of parameters measured by two observers was evaluated.Results The consistency of parameters measured by two observers was good (all ICC＞0.80).There was no statistical difference of CT values of liver and erector among A1-A4 subgroups (all P＞0.05),whereas statistical differences of SD values of liver and erector spinae,also of SNR and CNR of liver were found (all P＜0.001).Among A1-A4 subgroups,SDA4 ＜SDA2 ＜SDA3 ＜SDA1,SNRA4 ＞SNRA2 ＞SNRA3 ＞ SNRA1 (all P＜0.001) was observed.There was no significant difference of CNR between A1 and A3 subgroup (P=0.078),while CNRA4＞ CNRA2＞ CNRA3 or CNRA1 (P＜0.001) was noticed.SD values of the liver in subgroup A2 was lower than subgroup B1,and A4 was lower than B2 subgroup (all P＜0.001),and SNR and CNR increased significantly in A2 and A4 subgroups (all P＜0.001).CTDIvol of group A was lower than that of group B (P＜0.001).Conclusion Deep machine learning PS algorithm can improve image quality of abdominal low-dose plain CT scanning in high-BMI patients.

Influence of arterial data on Revolution CT perfusion parameters of renal cell carcinoma / 中国医学影像技术

Objective To explore the effect of whole renal perfusion imaging removal of arterial phase data on perfusion parameters of renal clear cell carcinoma using Revolution CT.Methods Perfusion imaging with Revolution CT was retrospectively analyzed in 10 patients with pathologically proven clear cell renal cell carcinoma.The z-direction coverage model was used in perfusion imaging,and the images were analyzed with CT Perfusion 4D software.All images were analyzed twice.All 23 phases data was included in group A and only 16 phases except arterial data (9-15 phases) were selected in group B.The abdominal aorta on the level of right hilus was chosen to be the input artery,and the perfusion parameter maps were obtained,including blood flow (BF),blood volume (BV),mean transit time (MTT),permeability of surface (PS).Every perfusion parameters of lesions and contralateral normal cortex,lesions and normal cortex in both groups were compared.Results The BF and PS of lesions were lower than those of normal cortex in both groups (both P＜0.05).There was no statistical difference in BV and MTT between lesions and normal cortex in both groups (all P＞0.05).There was no statistical difference in all perfusion parameters of renal clear cell carcinoma between group A and group B (all P＞0.05).The difference of BF in normal cortex between the two groups was statistically significant (P 0.009),and the difference of the PS,BV,MTT had no statistically significant (all P＞0.05).Conclusion When the duration time of renal CTP is 600 s,there is no difference between including and excluding arterial phase in all perfusion parameters of renal clear cell carcinoma.

The value of dual energy spectral CT in the differential diagnosis of mass type colorectal adenocarcinoma from colorectal adenoma / 中华放射学杂志

Objective To assess the value of spectral CT imaging in distinguishing mass type colorectal adenocarcinoma from colorectal adenoma. Methods Forty patients underwent preoperative abdominal dual energy spectral CT scan were analyzed restrospectively, including 17 with colorectal adenomas and 23 with mass type colorectal adenocarcinomas proven by endoscopic and surgical pathology. All patients underwent plain and three-phase enhanced CT scanning. The conventional polychromatic CT value and its pre- and postcontrast CT values, monochromatic CT value of 40 to 100 keV, the slope of spectral curve and iodine(water) concentration were measured, and the maximum diameter of the lesion was recorded. The maximum diameters of the lesions and imaging parameter differences between the adenomas and adenocarcinomas in plain and three-phase enhanced scan were analyzed with independent sample t tests. The data of the parameters with significant differences were further analyzed by ROC curves. Results The maximum diameters of the adenomas and mass type adenocarcinomas were (1.97 ± 0.54), (2.32±0.53) cm respectively, and there was no statistically significant difference (t=-2.011, P=0.051). There was no statistically differences of the conventional polychromatic CT value and its pre-and postcontrast CT values between the two groups in 4 phases (P>0.05). However, in the arterial phase, the CT values of adenomas were significantly lower than those of adenocarcinomas at low (40, 50 keV) energy (P0.05). The slope of spectral curve and the iodine(water) concentration both showed significant differences in the arterial phase between the two groups (P0.05).The largest area under the ROC curve of the iodine(water) concentration in the arterial phase was 0.757 in differentiating adenomas and mass type adenocarcinomas, with sensitivity of 73.9%and specificity of 82.4%at the cut-off of 21.02 mg/cm3. Conclusion Spectral CT imaging is valuable in differentiating colorectal adenoma from mass type colorectal adenocarcinoma with the parameters of the arterial phase.

Wide detector CT perfusion imaging features of adrenal adenoma / 中国医学影像技术

Objective To investigate the features of CT perfusion (CTP) parameters of adrenal adenoma (AA) using wide detector CT.Methods The wide detector CT scanning data of 21 patients with pathologically confirmed AA were retrospectively analyzed.CT perfusion (CTP) imaging was performed with the axis mode covering by 16 cm detector and ASiR-V50％.The image acquisition of CTP was performed after 6 s of injection of contrast media.Totally 26 consecutive volume acquisitions were contained.The arterial,venous and delayed phase images were obtained at the time of 22 s,51 s and 153 s after the injection,respectively.The blood flow (BF),blood volume (BV),mean transit time (MTT),time to peak (TP) and permeability of surface (PS) values of AA (group A) and contralateral normal adrenal gland (group B) were measured.All parameters between the two groups were compared,and the radiation dose was assessed.ROC curves were used to assess the diagnostic efficiency of CT perfusion parameters for AA.Results BV,MTT and PS values of group A were statistically lower than those of group B (all P＜0.05).There was no statistical difference of BF and TP values between the two groups (both P＞0.05).The area under the ROC curve (AUC) of BV,MTT and PS was 0.780,0.762 and 0.831,respectively.The sensitivity and specificity of diagnosis of AA was 95.2％ and 81.0％,respectively,when the threshold of PS was 1.37 ml/(100g · min).The effective dose (ED) of CT plain and CTP (including three-phase enhanced scan) were (3.20 ± 0.57) mSv and (19.98 ± 1.95) mSv.Conclusion Wide detector CT perfusion imaging can provide high-quality conventional three-phase enhanced images for diagnosis of AA,and provide effective quantitative perfusion data at the same time.PS value shows strong capability for diagnosis of AA.

Influence of Duration of Scan Acquisition on Perfusion Parameters of Whole Renal Perfusion by Wide Detector Multidetector CT / 中国医学影像学杂志

Purpose To explore the influence of duration of scan acquisition on perfusion parameters in whole renal perfusion with Revolution CT.Materials and Methods Fortytwo patients without pathologic changes in bilateral kidneys were divided into group A (with short perfusion time) and group B (with long perfusion time) according to the duration time of the perfusion scan.The Revolution CT axial scan mode was used for perfusion scan,and the width of detector was 16 cm.The perfusion CT series were performed in 50 seconds,each comprising 25 volumes with identical parameters (80 kVp,200 mA) in group A.The perfusion CT series were performed in 594 seconds,each comprising 23 volumes with identical parameters (120 kVp,55 mA) in group B.The source datasets were post-processed with CT Perfusion 4D software,and the perfusion parameter maps were obtained when right renal abdominal aorta was taken as entry artery.Perfusion parameters of bilateral kidneys were compared within and between group A and group B,respectively.CT dosage index of volume (CTDIvol) and dose length product (DLP) were recorded.The effective dose (ED) was calculated and compared.Results There were no statistical difference in all parameters between bilateral kidneys within each group (P＞0.05).However,blood volume,time to peak,and permeability surface in the cortex and medulla of bilateral kidneys all showed differences between the above two groups (P＜0.05).The mean transit time in the medulla between the two groups was different (P＜0.05),but neither the blood flow in the medulla and cortex nor the mean transit time of the cortex had difference between the two groups (P＞0.05).The effective radiation doses were (23.10± 4.39)mSv in group A and (23.19±0.00) mSv in group B,respectively (without statistic difference:P＞0.05).Conclusion CT perfusion parameters with different duration time show differences in whole renal perfusion;therefore,scanning time needs to be set according to the clinical application.

Feasibility of low radiation dose and iodine contrast medium in 70 kVp abdominal CTA in low body mass index patients / 中国医学影像技术

Objective To explore the feasibility of reducing radiation dose and iodine contrast medium in 70 kVp abdominal CTA imaging in low-body mass index (BMI;≤22 kg/m2) patients.Methods The 48 patients with suspected abdominal vascular diseases and low BMI (≤22 kg/m2) underwent abdominal CTA.All patients were divided into two groups according to tube voltage and contrast intake randomly.The parameters of group A (n=27) were contrast intake 300 mgI/kg,70 kVp,the conditions of group B (n=21) were contrast intake 500 mgI/kg,120 kVp,and the other conditions were the same in both groups.The image quality of right renal arterial images was evaluated by two observers simultaneously (5-scale).The consistency and difference between the two observers were analyzed.The CT values of abdominal aorta,celiac trunk,superior mesenteric artery,common hepatic artery,pancreatic artery and erector spinae,SD values of erector spinae on the level of right renal hilus were measured respectively in both groups.The CT values of abdominal aorta and its main branches,the CNR of abdominal aorta,the volume CT dose index (CTDIvol),dose-length product (DLP) and overall iodine intake in each group were compared.Results The scoring of right renal arterial images in both groups were 5.00 (1.00),the results showed a good consistency (Kappa=0.932,0.911).The CT values of abdominal aorta,superior mesenteric artery,common hepatic artery and pancreatic artery in group A were all more than those of in group B (all P＜0.05).The CNR of group A was higher than that of group B (P＜0.05).The CTDIvoland DLP in group A decreased by 73.36％ and 74.41％ compared with group B.The overall iodine intakes in group A and group B were (46.33±6.43)ml and (84.31±10.71)rnl,respectively.The overall iodine intake of group A decreased by 45.05％ compared with group B.Conclusion For patients with low BMI (≤22 kg/m2),a 70 kVp tube current abdominal CTA scanning can significantly increase the contrast of images of abdominal artery and its branches.Meanwhile,the radiation dose and overall iodine intake can obviously decrease.

Feasibility of whole-liver one-stop examination with Revolution CT / 中国医学影像技术

Objective To explore the feasibility of axial whole-liver one-stop examination with Revolution CT.Methods Totally 19 patients were underwent upper-abdominal enhanced examination with Revolution CT and acquired whole-liver CT perfusion (CTP),vein phase and balanced phase enhanced images.Two observers recorded the rank and peak CT value corresponding to time-density curve (TDC) of abdominal aorta and portal vein respectively on the CTP images.The perfusion parameters including blood flow (BF),blood volume (BV),hepatic arterial fraction (HAF),mean transit time (MTT),time to peak (TP) of left and right liver lobe were measured.The images of hepatic artery CTA and portal vein CTV were reconstructed and the arterial phase enhanced images were extracted using the images corresponding to abdominal aorta and portal vein peak TDC.And the radiation dose of CT perfusion and one-stop examination were recorded.The differences between perfusion parameters of left and right liver lobe were compared and the consistency of two observers were analyzed.Results The differences between BV and MTT of left and right liver lobe were statistical significance (both P＜0.05).The subjective scores of hepatic artery CTA,portal vein CTV and arterial phase images were greater than 1 point.The two observers were in great consistence (Kappa＞0.6).The effective radiation dose in perfusion phase and one-stop examination were 14.47 mSv and 21.29 mSv.Conclusion With low radiation dose,Revolution CT axial wholeliver perfusion one-stop examination can provide multiple quantitative parameters of liver CTP and clear hepatic artery CTA,portal vein CTV and 3 phase enhanced scan images,which has broadly prospective in clinical application.

Feasibility of one-stop examination with wide detector CT for axial perfusion of pancreas / 中国医学影像技术

Objective To explore the feasibility of one-stop examination with Revolution CT for axial perfusion of normal pancreas.Methods Thirteen patients who received axial perfusion scan by one-stop examination with Revolution CT were analyzed as perfusion group.Two radiologists measured pancreatic CT perfusion (CTP) parameters independently and selected optimal phase for CTA and three phases of enhanced images.The effect dose (ED) was calculated.Eighteen patients who underwent abdominal enhanced CT and CTA with spiral scan were included as control group.Patients in both groups had no pancreatic disorders.The interobserver variation of CTP parameters was estimated.Two independent radiologists separated the superior pancreaticoduodenal artery (SPDA) image into 5 points according to image quality,and the consistency was assessed.The subjective points of SPDA image quality of two groups was compared.CT value,images noise,CNR and SNR of SPDA on CTA images and those of pancreas on three phases enhanced scan images between two groups were compared.Results ICC values of all CTP parameters were higher than 0.75.The ED of perfusion protocol was (24.52±-0.01)mSv.The subjective image scores of SPDA on CTA images in both groups were both 5,the consistency was good (Kappa=0.629,0.769).The CT value,CNR,and SNR of SPDA on CTA images of CTP group were higher than those of control group (all P＜0.05).The CT value,CNR,and SNR of pancreas of CTP group were higher than those of control group in venous phase and balanced phase (all P＜0.05).Conclusion The pancreatic CT one-stop examination can be performed by Revolution CT scanner with maximum detector width with acceptable radiation dose,from which pancreatic CT perfusion data,enhanced images with high quality and better CTA images can be extracted.

The detection value of single source-dual energy CT for bladder cancer with hematoma / 实用放射学杂志

Objective To assess the utility of single source-dual energy CT for distinguishing bladder cancer from hematoma. Methods We retrospectively identified 14 patients with postoperative or follow-up bladder hematoma who had undergone dual energy protocol (40-140 keV)scanning by single source-dual energy CT.The subjective scoring of tumor detection and image quality,the optimal monochrome images and iodine-water images were evaluated by two radiologists who didn’t know the results.The consistency of two observers was analyzed by Kappa test.Mann-Whitney U test was used to compare the difference between the two kinds of diseases and ROC curve was used to analyze the diagnostic efficiency.The statistical differences of image quality scoring among different images were obtained by using Mann-Whitney U test.Results The consistency of the two observers about scoring of lesion detection was good for all groups.There were statistical differences between two groups in non-enhanced phase and arterial phase of mixed-energy images,non-enhanced phase,arterial phase and delayed phase of optimal monochromatic images,and all phase of iodine-water images. The AUC of iodine-water images in the four phases (0.985,1.000,0.955,0.924,respectively)were all higher than that of polychrome unenhanced and arterial phase images (0.909,0.909).The diagnostic efficiency of arterial phase on iodine-water images was the highest.Sensitivity and specificity were both 100% when score was greater than 2.5.There was no statistical difference between two kinds of diseases on non-enhanced phase,delayed phases of mixed-energy or monochromatic images(P >0.05).There were no statistical differences in image quality scoring among the three groups with the same phases (P>0.05).Conclusion Optimal monochromatic images and iodine-water images of single source-dual energy CT are more effective than conventional CT in distinguishing bladder cancer from hematoma.

Relationship of correction coefficient and measuring position in spectral CT imaging / 中国组织工程研究

BACKGROUND:In spectral CT imaging study, the selection of scanning parameters is considered by most researchers, but the effects of measuring position are often overlooked. Actual measurement found that different measurement location had significant impact on the result of the measurement. Through measurement and mathematical model of a large amount of data, we can correct the measurement results of different location. The results with real data alignment are higher. OBJECTIVE:To explore effects of different measuring positions on results in spectral CT imaging, and to optimize correction coefficients. METHODS:GE standard water phantom was applied to orderly obtain 5 combined scanning parameters with 552 groups of data. Size measurement method was divided into two measuring range:ROI1 and ROI2. We selected 10 points to measure CT value, including Center, North, South, West and East. The measurement data of ROI1 and ROI2 were classified and screened based on the same sequence. Mathematical modeling and probability statistics analysis were used to optimize correction coefficient, get calibration function and draw experimental simulation curve. RESULTS AND CONCLUSION:(1) Measuring methods of ROI1 were superior to the ROI2’s on water phantom in spectrum CT. (2) To different scanning sequences, the measuring results were different. To the same scanning sequences, the measurements for different positions on water phantom in spectrum CT had remarkable influence on the measuring results, which varied from points to points. (3) Through setting up mathematical modeling, using method of statistical analysis, we could get the correction function on different measuring positions. (4) Above results confirmed that compared with the theoretical model and the experimental data of spectral CT scanning parameters, the coefficients of position can be adjusted, which can optimize the measuring results.

Analysis of willingness and influencing factors for usage of pre-exposure prophylaxis among male u-niversity students who have sex with men / 中华行为医学与脑科学杂志

Objective To analyze the willingness and influencing factors for usage of pre-exposure prophylaxis(PrEP) among male students who have sex with men (MSM) in universities of Guangxi. Meth-ods 295 MSM students in universities were recruited by Snow-balling methods. Questionnaires were self-administered to collect social demographic information,AIDS related risky sexual behaviors and willingness for usage of PrEP. Logistic regression was employed for univariate and multivariate analysis. Results Of the 295 MSM,58(19.7%)had ever heard PrEP,265(89.8%) said that they would like to use PrEP. Multivari-ate logistic regression analysis showed that those who had found partners through friends ( OR=11.419,95%CI:1.363~95.641), those who would advise his friend to use PrEP ( OR=87.946,95%CI:13.660-566. 222),those who concerned the convenience to gain the medicine ( OR=119.652,95%CI:3.765-3802.184) and those who said that they could take medicine every day ( OR=88.245,95%CI:10.237-760.696) were more likely to accept PrEP. The subjects whose partners would be angry if they stick to use condoms( OR=0.106,95%CI:0.019-0.606),and those who suspected the effectiveness of drugs( OR=0.010,95%CI:0. 001-0.112) were less likely to accept PrEP. Conclusion The acceptability of PrEP is high in university students'MSM. The safety of drugs and the convenience to gain the medicine are the main influencing factors for usage of PrEP.Using of PrEP should be strengthened to the MSM.

Effect of Low Contrast Dose and Low Tube Voltage Combined with Adaptive Statistical Iterative Reconstruction in the Image Quality of Abdominal CT Angiography / 中国医学影像学杂志

Purpose To investigate the effect of low contrast dose and low tube voltage combined with adaptive statistical iterative reconstruction (ASIR) on image quality of abdominal CT angiography. Materials and Methods 139 patients with body mass index (BMI) 0.80) in both groups, the subjective score of group A and group B were 4.60±0.51 and 3.81±0.76, respectively, and the difference was statistically significant (Z= - 6.86, P0.05). The total amount of iodine dose in group A and group B was 270 mg and 350 mg respectively, with a 22.86% reduce of the total iodine for each patient in A group than in B group. Conclusion For patients with BMI<22 kg/m2, it is feasible to use low dose contrast medium with low tube voltage and ASIR, which may not only improve the image quality of abdominal CTA but also reduce the radiation dose and iodine content.

Application value of optimal energy imaging technique of monoenergetic dual-energy computed tomography in feeding arteries examination of rectal cancer / 中华消化外科杂志

Objective To explore the application value of optimal energy imaging technique of monoenergetic dual-energy computed tomography (DECT) in feeding arteries examination of rectal cancer.Methods The clinical data of 33 patients with rectal cancer who were admitted to the First Affiliated Hospital of Dalian Medical University from July 2012 to July 2014 were analyzed retrospectively.The polychromatic and monochromatic images of feeding arteries of tumors were reconstructed and evaluated using a subjective image quality score of 5-point scale by 2 observers.The consistency and scores of evaluation were analyzed by the κ test and MannWhitney U test.The CT value of feeding arteries of tumors and hip muscle,image noise and contrast to noise ratio (CNR) were measured and calculated by 2 observers,and were compared by the independent sample t test.The consistency of data between the 2 observers were measured by the intra-class correlation coefficients (ICC).Results Inferior mesenteric arteries were contributor of blood supply of tumors in all the 33 patients,including 4 cases with right inferior rectal artery as contributor of blood supply of tumors,2 cases with bilateral inferior rectal artery.Among patients with abnormal blood vessels,there were 8 patients with left colic artery and sigmoid artery having common trunk,4 patients with left colic artery originated from Inferior mesenteric artery,1 patient with absence of left colic artery.The 0-,1-,2-,3-,4-score polychromatic image quality of feeding arteries of tumors were detected in 0,13,13,5,2 patients and 0,11,14,6,2 patients by 2 observers,respectively.The 0-,1-,2-,3-,4-score monochromatic image quality of feeding arteries of tumors were detected in 0,0,7,7,19 patients and 0,0,6,9,18 patients by 2 observers,respectively.Good interobserver agreement was found for the evaluation of subjective scores (κ =0.864,0.897).The subjective scores of image quality of feeding arteries in the polychromatic images and in the monochromatic images were 1.9 ± 0.9 and 3.4 ± 0.8,with significant difference (Z =-5.21,P ＜ 0.05).The latter was superior to the former.The ICC values of the CT values of feeding arteries of tumor,hip muscle,image noise and CNR were 0.953,0.907,0.839,0.964 and 0.966,0.933,0.952,0.962 from the 2 observers,with a good consistency.The CT values of feeding arteries of tumor,gluteal muscles,image noise and CNR in the polychromatic images and in the monochromatic images were (234 ± 52)HU and (412±83)HU,(57±9)HU and (71 ±15)HU,(21 ±3)HU and (31 ±6)HU,9 ±3 and 11 ±4,respectively,with significant differences (t =-18.65,-4.44,-14.14,-6.55,P ＜ 0.05).The levels of monochromatic images of 33 patients were 51-61 keV,with a median of 55 keV.Conclusion The optimal energy imaging technique of monoenergetic DECT can improve the angiographic quality of feeding arteries in patients with rectal cancer.

A Preliminary Study of Energy Spectrum CT on Showing Feeding Arteries of Gastrointestinal Tract Malignant Tumors with Low Concentration Contrast Medium / 中国医学影像学杂志

PurposeTo investigate the effects of the low concentration contrast medium combined with optimal single source spectral imaging on displaying feeding arteries of gastrointestinal tract malignant tumors.Materials and Methods Seventy-one patients of body mass index (BMI) >25 kg/m2 with gastrointestinal tract malignant tumors were prospectively studied. All the cases were randomly divided into two groups: high concentration group (33 cases with high concentration contrast medium of 350 mgI/ml in routine scan) and low concentration group (38 cases with low concentration contrast medium of 270 mgI/ml in optimal single source spectral imaging). The optimal single source images were generated automatically. The subjective image scores, CT value of the tumor feeding arteries, image noise, contrast-to-noise ratio (CNR) and CT dose index of volume (CTDIvol) of optimal single source spectral images in two groups were compared. Results The optimal single source of low concentration group were 51-60 keV. The subjective image score of low concentration group was higher than high concentration group (Z=-4.280,P0.05).Conclusion The low concentration contrast medium with optimal single source spectral imaging in patients with large BMI may improve CTA image quality of feeding arteries of gastrointestinal tract malignant tumors without increasing radiation dose.

A systematic evaluation on the quality of Meta-analysis in articles published in the Chinese Journal of Gastrointestinal Surgery from 1998 to 2014 / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To assess the methodological quality and reporting quality on Meta-analysis being published in the Chinese Journal of Gastrointestinal Surgery.</p><p><b>METHODS</b>Computerized literature searching was carried out in Wanfang Medical Online to collect articles that Meta-analysis was used in the Chinese Journal of Gastrointestinal Surgery since it was founded till July, 2014. Manual retrieval was also conducted. Two researchers independently screened for literature and extracted data. Qualities on methodologies or on the processes of reporting and reviewing were evaluated by both AMSTAR and PRISMA scales.</p><p><b>RESULTS</b>Forty-two papers on meta-analyses were included in this study. Results on the quality of methodology evaluation showed that the lowest and highest scores were 6 and 9 respectively, the median score was 7. Two articles (4.8%) were rated as high, 40 articles (95.2%) as moderate and 0 articles (0%) as low. Although the quality of methodology was above the average, however, there were still some problems seen in some papers as the conflict of interest was not stated, the list of studies (included and excluded) was not provided, a comprehensive literature search was not performed, the likelihood of publication bias was not assessed, etc. Results on the quality of reporting evaluation showed that the lowest and highest scores were 14 and 22 respectively, the average score was 18.43 ± 2.03, 3 articles (7.1%) scored less than 15 points, 35 articles (83.3%) scored 15.5-21 points, and 4 articles (9.6%) scored 21.5-27 points. The included reviews had high quality on the titles of the report, inclusion criteria, rationale of introduction, synthesis of results, results of individual. However, the abstract, objectives of introduction, scheme and registered, inclusion criteria, research screening, additional analysis, conclusion limitations, funding support etc. were lack of comprehensive reports.</p><p><b>CONCLUSIONS</b>Articles on Meta-analysis published in the Chinese Journal of Gastrointestinal Surgery are of high quality. The Chinese Journal of Gastrointestinal Surgery can provide better evidence for clinical decision to gastrointestinal surgeons. However, both of qualities on methodology and reports sill call for continuous improvement.</p>

Optimization and standardization of imaging parameters for 16-slice spiral CT angiography in intracranial and cervical arteries / 中国医学影像技术

Objective To explore the optimization and standardization of imaging parameters for 16-slice spiral CT angiography in intracranial and cervical arteries. Methods Sixty patients were randomly divided into three groups, and the automatic bolus tracking thresholds of 100, 150 and 180 HU in the descending aorta were used respectively. The CT values of artery and vein among three groups were compared. Other 40 patients were randomly divided into A and B group and underwent CTA with different slice thickness and pitch, and the difference in arterial display were compared. Results The carotid and intracranial arteries in all three groups were well displayed. No statistical difference was found in enhancement CT values of three points of common carotid artery and internal carotid artery among three groups (P>0.05), while the differences of CT values in same level vein among three groups were significant (P<0.05). There was no significant difference in the average score of display degree between group A and B. Conclusion Imaging parameters for 16-slice spiral CT angiography in intracranial and cervical arteries are recommended as follows:100 HU (threshold), 120 kV, 280 mA, 1.25 mm (thickness), 1.375:1 (pitch), 0.5 s/r and 16×0.625 mm (effective thickness).