Objective To investigate perfusion imaging and parameters of normal pancreas by dual-source CT and to evaluate the appropriate perfusion imaging scan.Methods Sixty-six subjects with normal pancreas underwent low-dose pancreatic perfusion and plain scan.CT images were sent to a separate workstation via a network.The blood flow (BF)and blood volume (BV)of pancreas head,body and tail were measured using the VPCT Body software and analyzed by one-way ANOVA.Then the time-density curve of pancreas was drawn,and the enhancement peak time and the corresponding CT value were also measured.Results The average BF values of pancreas head,body and tail were (1 1 6.09 ± 31.83)mL·100 g-1 ·min-1 ,(1 1 9.72±32.50)mL·100 g-1 ·min-1 , (1 14.65±31.42)mL·100 g-1 ·min-1 ,and the mean BV values were (29.83 ±1 9.07)mL/100 g,(30.39 ± 1 9.38)mL/100 g, (28.82±1 9.22)mL/100 g,respectively.The perfusion parameters in different pancreatic parts were not statistically different.The mean enhancement peak time was (27.92 s±4.52)s,(28.02±5.34)s in pancreas head,(27.40±4.36)s in pancreas body,(27.34±4.57)s in pancreas tail.On plain image,the average CT value of pancreas was (41.43±5.88)HU.However,on enhanced image,the mean CT value was (95.96±18.44)HU in normal pancreas [(96.73±19.71)HU in pancreas head,(98.45±17.52)HU in body,(92.69±18.1 7)HU in tail].Conclusion The perfusion parameters including blood flow and blood volume in pancreatic head,body and tail are identical. The mean enhancement peak time is (27.92±4.52)s,and the corresponding enhancement CT value is (95.96±18.44)HU.

Objective To observe the display and source of the artery located at anterolateral region next to pancreatic head on en-hanced CT,and to investigate its clinical value.Methods Imaging data of 200 consecutive patients who underwent abdominal CT scan were collected,and their CT images were analyzed.The reconstructed images were obtained at a post-processing workstation. After reconstruction,the display rate,source and branches of the artery located at anterolateral region next to pancreatic head were analyzed,and the diameters of these vessels were measured.Results The arterial vessel located at anterolateral region next to pan-creatic head was found on axial CT image in arterial phase with a display rate of 100%.By using post-reconstruction images,most vessels were gastroduodenal artery with mean diameter of 0.33 cm± 0.05 cm,and other ones were pancreaticoduodenal artery or right gastroomental artery.Conclusion The artery located at anterolateral region next to pancreatic head can be found on axial ab-dominal CT image in the arterial phase.Most vessels are gastroduodenal artery with a fixed position and traveling.

Objective To explore the application value of monoexponential, biexponential models multiple b values diffusion weighted imaging(DWI) in distinguishing pancreatic cancer from non-tumorous pancreas.Methods Subjects comprised 37 pancreatic cancers confirmed by clinical or surgery.Pancreas multiple b values DWI was performed using 3.0T scanner.Standard apparent diffusion coefficient (ADCstandard) was calculated using monoexponential diffusion model.Pure diffusion coefficient (ADCslow), pseudodiffusion coefficient (ADCfast) and perfusion fraction (f) were calculated using intravoxel incoherent motion(IVIM) diffusion model.Parameters of pancreatic cancers and non-tumorous pancreas were compared using independent samples t test.Results Mean ADCslow value of pancreatic cancer was higher than that of non-tumorous pancreas (0.611×10-3 mm2/s vs 0.521×10-3 mm2/s,P=0.037).Mean ADCfast and f values of pancreatic cancer were lower than that of non-tumorous pancreas (5.066×10-3 mm2/s vs 7.188×10-3 mm2/s,P=0.035;55.8% vs 64.0%,P=0.016;respectively).ADCslow of pancreatic cancer was positively correlated to ADCstandard (r=0.824,P=0.000).ADCfast of pancreatic cancer was negatively correlated to f(r=-0.558,P=0.000).Conclusion ADCslow, ADCfast and f derived from IVIM-DWI model can distinguish pancreatic cancer from non-tumorous pancreas.IVIM-DWI may be a promising and non-invasive tool for early diagnosing and differentiating pancreatic carcinoma from non-tumorous pancreas.

Objective To evaluate the value of DWI and ADC value in monitoring the chemotherapy response of advanced gastric carcinoma dynamically.Methods 42 advanced gastric carcinoma patients who were confirmed by histopathology underwent T2 WI and DWI examinations at pre-chemotherapy,post-chemotherapy 3 d,7 d,30 d and 60 d respectively.The longest diameters of tumor pre-chemotherapy and post-chemotherapy 60 d were measured on axial T2 WI,meanwhile the ADC values at different time points were calculated.The mean ADC value among pre-and post-chemotherapy of each group (PR and SD)was compared.Results The ADC value of PR group increased gradually.The mean ADC value before therapy was statistically lower than those at differ-ent time points post-chemotherapy (P < 0.05).The ADC value of SD group increased gradually from pre-chemotherapy to post-chemotherapy 30 d,and then the ADC value decreased at post-chemotherapy 60 d.The differences of the mean ADC values in differ-ent time points were statistically significant (P < 0.05).Conclusion DWI and ADC value can dynamically,quantitatively and early detect and monitor the chemotherapy response of advanced gastric carcinoma.

Objective To analyze preoperative CT angiography (CTA)imaging features of cervical arteries in patients with acute type A aortic dissection followed by postoperative neurological dysfunction (ND),and the correlations between risk factors and ND.Methods Clinical and imaging data of 110 patients who underwent repair of acute type A aortic dissection were analyzed retrospectively.The samples were categorized into two groups based on the presence or absence of ND.The clinical,perioperative and imaging data were compared between the ND group and the non ND (NND)group.Univariate and multivariate analyses were performed to identify predictors related with ND.Results A total of 100 patients were finally included in this study,and 18 patients(18%)developed with ND after aortic surgery.No significant differences in clinical and perioperative variables were observed between the ND group and the NND group (P＞0.05).However,on preoperative CT images,a dissection entry localized in the aortic arch (94.4% in the ND group), common carotid artery tear (83.3% in the ND group)and unilateral internal carotid artery density decrease (44.4% in the ND group) were all significantly higer than those in th NND group (P＜0.05 ).No significant difference were observed in true lumen stenosis of ascending aorta (P=0.053),retrograde dissection (P=0.913)and intimal tear (P=0.267)between ND group and NND group.The Logistic regression analysis revealed that a dissection entry localized in aortic arch (OR=21.325,P=0.008),common carotid artery tear (OR=14.441,P=0.022)and unilateral internal carotid artery density decrease (OR=9.141,P=0.024)were independent determinants of postoperative ND.Conclusion Preoperative CTA of cervical arteries can provide more imaging features,that may be indicative of postoperative ND.

Objective To investigate the methods of screening specific aptamers for (EpCAM)Gpositive prostate cancer (PCa)cells by cellGSELEX technique.Methods A random DNA library was designed to screen EpCAMGspecific DNA aptamers from human prostate cancer cells expressing EpCAM molecule by cellGSELEX technique.After 12 rounds of in vitro screening,DNA products were cloned and sequenced.Flow cytometry and cellular immunofluorescence were used to detect the specific binding ability of aptamers to target cells.Results Two aptamers of Ep1 and Ep2 were selected.Both of them could specifically bind to EpCAMGpositive cancer cells LNCap,PCG3 ,DU1 45 , and HEK293T cells transfected with target molecule.The binding rates of Ep1 were 61.0%,74.3%,5 9.1% and 60.3%.The binding rates of Ep2 were 65.1%,77.8%,54.2% and 58.3%.Neither of them could bind to HEK293T cells transfected with empty vector with the binding rate of 5.4% in Ep1 and 3.3% in Ep2,respectively.Flow cytometry analysis and confocal images indicated that the EpCAM aptamers could specifically recognize human PCa cells expressing EpCAM,but could not bind to EpCAMGnegative cells.Conclusion EpCAM aptamers derived from cellGSELEX technology can recognize and bind to EpCAMGpositive PCa cells specifically,which may provide new ideas for the specific diagnosis and targeted therapy of prostate cancer,and lay an experimental basis for the other specific diagnosis and treatment schemes of malignant tumors.

Objective: To explore the effect of breastfeeding duration on age at adiposity rebound, and provide a scientific theoretical basis for identifying early life factors of obesity in children and adolescents, while promoting early intervention. Methods: In September 2019, first graders from a primary school in Minhang District, Shanghai, were selected to participate in this study, and their growth information was retrospectively collected. The natural cubic spline function was used to fit the body mass index trajectory of the subjects from 1 to 80 months, and age at adiposity rebound was calculated. A total of 6 148 subjects were selected, and complete data of adiposity rebound timing and breastfeeding duration were obtained. A multiple linear regression model was used to analyze the relationship between these two variables. Results: The average breastfeeding duration of all children included in the study was (3.71±3.28) months, and most of the subjects (69.63% for male and 70.45% for female) were breastfed for less than 4 months. A positive linear relationship was found between them [male, B =0.16(0.02-0.30), female, B =0.34(0.18- 0.51 ), total, B =0.23(0.12-0.34), P <0.05]. The linear relationship was determined using the multivariate model. Conclusion Breastfeeding duration independently affected age at adiposity rebound. Prolonging the duration of breastfeeding within 24 months of age may help to delay the timing of adiposity rebound,and thus reduce later risks of overweight and obesity.

Objective: To explore the influence of birth weight and growth patterns during infancy on overweight and obesity among first grade primary school pupils, so as to provide a theoretical basis for the formulation of early life prevention and intervention policies. Methods: In 2019, data related to routine physical examinations were collected for primary school pupils in the Minhang District of Shanghai, and information regarding birth and follow ups was collected retrospectively. Physical examination data of 4 434 pupils at 12 months of age were obtained. A multiple linear regression model was used to analyze the relationship between growth patterns during infancy and body mass index (BMI) in the first grade of primary school. A generalized linear model was employed to analyze the relationship between birth weight and growth patterns during infancy and overweight and obesity in the first grade of primary school. A hierarchical analysis was conducted. Results: A linear relationship was observed between growth patterns during infancy and BMI and the BMI Z score of first grade primary school pupils [ β(β 95%CI)=0.30(0.24-0.35),0.12(0.10- 0.15 ), P <0.01]. In addition to subjects classified as small for gestational age (SGA), catch up growth during infancy was identified among subjects who were classified as appropriate for gestational age (AGA) and large for gestational age (LGA). LGA at birth and catch up growth during infancy were independent risk factors for overweight and obesity among first grade primary school children ( RR =1.31-1.55, P <0.05). The hierarchical analysis showed that catch up growth increased the risk of overweight and obesity among first grade primary school pupils classified as AGA [ RR(RR 95%CI )=1.74(1.42-2.14),1.87(1.56-2.26)], and increased the risk of obesity among first grade primary school pupils classified as SGA and LGA [ RR(RR 95%CI )=3.74(1.04-13.49),3.24(1.62-6.46)]( P <0.05). Among those who exhibited catch up growth during infancy, LGA increased the risk of obesity among first grade primary school pupils ( RR= 2.60 , 95%CI=1.35-5.02, P <0.01), but not the risk of being overweight ( P =0.13). Conclusion Birth weight and growth patterns during infancy have an impact on overweight and obesity among children in the first grade of primary school. It is suggested that attention should be paid to growth and physical development in early life for those classified as LGA and AGA, and catch up growth in children should be closely monitored.

Objective: To explore the characteristics of the adiposity peak and rebound in early life among first year primary school students with different body weight measures, so as to provide scientific evidence for the development of prevention interventions to manage childhood overweight and obesity. Methods: A total of 2 330 first year primary school students who received routine physical examinations from September to December in 2019 were selected. According to body mass index (BMI) status, participants were divided into three categories:healthy weight, overweight, and obese. The BMI growth trajectories of the three groups were fitted by gender using the generalized additive mixed model from 1 to 80 months, retrospectively. Each subject s age at the adiposity peak and rebound, and associated BMI values, were calculated. Results: The prevalence of overweight and obesity was 16.31 % (380/ 2 330 ) and 16.09% (375/2 330), respectively. For first year students with obesity, the BMI value continued to be higher than their overweight or healthy weight counterparts during the first 80 months of life. The age at the adiposity peak for these students, whose BMI status varied, was about nine months. However, the BMI of children with overweight or obesity was much higher than that of healthy weight subjects. Age at adiposity rebound was 72 months for healthy weight children, 52 to 55 months in children defined as overweight, and 22 to 23 months in children with obesity. For healthy weight children, the fitted value of BMI at the adiposity rebound was less than that of overweight and obese children. Conclusion Age at the adiposity peak was largely similar among first year students with different BMI patterns; however, age at adiposity rebound was different. Age at adiposity rebound among children with obesity was much earlier than that of other subjects, and their BMI values were much higher.

Purpose To explore the application of intra voxel incoherent motion diffusionweighted imaging (IVIM-DWI) quantitative parameters in evaluating the pathological stage of pancreatic cancer by comparing the manifestations of IVIM-DWI in patients with pancreatic cancer in different differentiaed degrees as there lacked effective screening instrument for the early diagnosis of pancreatic cancer.Materials and Methods Sixteen patients with pathologically proved pancreatic cancer (10 with high-moderation differentiation while 6 with low differentiation) were enrolled,and 3.0T MRI was used to conduct pancreatic DWI with multiple b values.IVIM double-exponential model was used to analyze the measurement parameters of DWI with multiple b values,so as to measure the slow apparent diffusion coefficient (ADCslow),fast apparent diffusion coefficient (ADCfast) and filling fraction (f).Results The ADCslow value was evidently lower in patients with high-moderate differentiated pancreatic cancer than those with low differentiated pancreatic cancer [(0.546± 0.041)× 10-3 mm2/s vs.(0.677± 0.120)× 10-3 mm2/s,P＜0.05],and f value was notably higher in patients with high-moderate differentiated pancreatic cancer than those with low differentiated pancreatic cancer [(59.3 ± 8.8)％ vs.(41.7±22.4)％,P＜0.05].The area under the curve of ADCslow was higher than that of f when distinguishing high-moderate differentiated and low differentiated pancreatic cancer (0.850＞0.750).The sensitivity and specificity were 100.00％ and 83.33％ when ADCslow ≤ 0.599×10-3 mm2/s,and were 100.00％ and 66.67％ when f＞44.7％ in distinguishing high-moderate differentiated and low differentiated pancreatic cancer,respectively.Conclusion ADCslow and f,as the quantitative parameters for IVIM-DWI,can distinguish high-moderate differentiated and low differentiated pancreatic cancer,and predict the pathological stage of pancreatic cancer before operation.Moreover,they also have high diagnostic efficacy in distinguishing high-moderate differentiated and low differentiated pancreatic cancer.