Objective To investigate the methods and effects of abdominal and pelvic shielding for pediatric chest CT examinations.Methods The 705-D phantom made by Computerized Imaging Reference Systems (CIRS) was used to replace a 5-year-old child,thermoluminescent dosimeters were set in the abdomen and pelvis to measure the organ and tissue doses.Chest scans were conducted with the routine protocol for pediatric chest CT examinations.Doses to main organs and tissues in the abdomen and pelvis were measured after chest CT scans without lead apron,with lead apron covering anterior of the abdomen and pelvis and with apron wrapping same part,respectively.Results Absorbed doses to some abdominal organs near the irradiation field were up to several mGy in a procedure of pediatric chest CT examination.There were statistically significant differences among the dose values for three different scans at the same location (x2 =16.00,P ＜ 0.05).Statistically significant difference was also found between the dose values for scans,which were measured with wrapping and covering approaches (Z =-2.52,P ＜ 0.05).Compared to the doses in the condition of no shielding,the doses in testis and colon reduced by 71.2％ and 42.3％,respectively,if the abdomen and pelvis was wrapped with a lead apron (0.35 mm Pb),and reduced by 55.9％ and 26.1％,respectively,if the same lead apron was used to cover the anterior of the abdomen and pelvis.Conclusions In pediatric chest CT examinations,the use of a lead apron can effectively shield the abdomen and pelvis,and plays an important role in protection of the gonad and colon.The wrapping measure is worth being recommended.

Objective To investigate rare and atypical imaging manifestations of abdominal lesions associated with IgG4-related disease (IgG4-RD).Methods Forty-one patients with IgG4-RD proved histopathologically or clinically were investigated retrospectively.All the patients underwent precontrast and dynamic enhancement scan of the abdomen.CT was performed in 32 patients and MR imaging in 27 patients (including both of CT and MRI in 18 patients).Whether tissue and organs of the abdomen were involved was observed,especially rare and atypical imaging manifestations including focal pancreatic lesion,pseudocyst and (or) abscess as well as calcification of pancreas,peripheral blood vessels of pancreas involvement and mass-like lesions were existed.Involvement of the organs including liver,gallbladder,spleen,gastrointestinal tract,mesentery and their manifestations were also observed.Results One to four abdominal organs were involved,the numbers of involved organs were as follows:one organ in 13 patients (31.7％),two organs in 12 patients (29.3％),three organs in 13 patients (31.7％),and four organs in 4 patients (7.3％).The most commonly involved organ of the abdomen was the pancreas which was found in 35 patients.Abdominal extrapancreatic lesions were found in 33 patients.Focal involvement of pancreas as a rare manifestation showed in 11 cases (11/35,31.4％).The patterns were focal and multifocal.Rare cases showed pseudocysts (3/35,8.6％) and abscess was found in 1 case.Capsule-like rim was present around the pancreas lesions in 25 cases.Ten cases showed thick and wide rim with unclear boundaries with adjacent blood vessels,and 7 of them showed the peripheral blood vessels surrounded.Bile duct involvement was observed in 26 patients,and gallbladder involvement was observed in only 2 of them.Rare renal involvement patient has mass-like lesion,with hypointensity on T2WI,then showed decreased enhancement and gradually delayed enhancement.One retroperitoneal fibrosis patient also showed mass-like lesion as an atypical and rare manifestation.Three IgG4-related liver inflammatory pseudotumors were found in 2 patients.Lesions showed iso or hypointensity on T2WI,continuously enhancement,with abnormal edge ring.Mesentery involvement was found in 1 patient.Conclusion Several abdominal lesions associated with IgG4-RD have rare and atypical imaging manifestations.There are specific imaging characteristics,which are helpful for most accurate diagnosis of IgG4-RD.

Objective To investigate the feasibility of subtraction coronary computed tomography angiography (Sub-CCTA) for the diagnosis of coronary heart disease in the segment with severe calcification.Methods A retrospective analysis was performed on 27 patients who underwent clinically indicated digital subtraction angiography (DSA) and CCTA using a 320-detector row CT.Compared with the results of DSA,sensitivity,specificity,positive predictive value,negative predictive value and accuracy of Con-CCTA and Sub-CCTA were calculated.The clinical diagnostic accuracy of the two imaging methods was evaluated using the receiver operating characteristic (ROC) curve.The stenosis of coronary segments was divided into four grades (Ⅰ,Ⅱ,Ⅲ,Ⅳ).Kappa coefficient was used to measure agreement between two imaging methods.Image quality of 4-scale grade scoring method was used and t test was conducted.Results A total of 52 segments with severe calcification were evaluated.The scores of image quality in Con-CCTA and Sub-CCTA were 2.8 ± 0.5 and 3.4 ± 0.7,respectively.There was significant difference between them (t =5.9,P ＜ 0.05).Compared with the result of DSA as the golden standard,the Kappa coefficients were 0.55 and 0.81 respectively in Con-CCTA and Sub-CCTA for the quantitative evaluation of the severe calcified segments.The sensitivity,specificity,positive predictive value and negative predictive value and accuracy of Con-CCTA were 81.0％,63.1％,63.1％,81.1％ and 70.8 ％;and for Sub-CCTA they were 90.5 ％,85.2％,82.1 ％,92.0％ and 87.5 ％ respectively.Compared with Con-CCTA,the area under the ROC curve of Con-CCTA and Sub-CCTA were 0.84 (95％CI:0.70-0.93) and 0.96 (95％ CI:0.86-1.00),respectively,and the difference was statistically significant (P =0.03).Conclusions Sub-CCTA can improve the diagnostic accuracy of coronary artery stenosis in severe calcified segment.Application of subtraction technique in CCTA can reduce or even eliminate the artifacts caused by severe calcified plaque,and has a good clinical application prospect.

Objective: To investigate the clinical avalue of real time threshold manual triggering technique in the lower extremity arterial CT angiography .Methods :A total of 70 patients with clinically suspected lower extremity arterial disease underwent lower extremity arterial CT examination ,and the patients were randomly divided into two groups .In the first group 35 patients ,the automatic threshold triggering technique was used .After the threshold reached to 150 Hu ,6 s was delayed before scanning .The other group of 35 patients with manual triggering was used to observe the time density curve .When the peak value was stable ,scanning was started at once .The delay time of the two groups was analyzed and the image quality of the two groups was evaluated .The image quality evaluation included the branch level ,the smooth degree of the arterial edge , the interference of the vein and the CT value of the arterial segment .Results:There were significant differences in the starting delay time of the two trigger modes (P=0 .002 ,P<0 .05) ,and the auto trigger group was earlier than the manual triggering group .Between the two trigger modes ,there was no significant difference in the distal branches and vessel edge of abdominal‐iliac artery and femoral popliteal artery display ability .In the lower limb artery ,the image quality of manual triggering group was higher than that of the automatic trigger group ,the two groups had statistical significance (P=0 .004 , P=0 .003) .The same as to the distal branch and the edge of the vessel of the foot (P=0 .003 ,P=0 .003) .Two sets of images in the lower limb vein interference score had no significant difference ( P> 0 .05 ) .CT value had no significant difference in abdominal‐iliac artery ,femoral‐calf and popliteal arteries between the two groups ,while that in the dorsalis pedis artery had statistical significance between the two groups (P=0 .006) .Four levels of CT values in manual triggering group were higher than those in the automatic trigger group .Conclusions :Real time threshold manual triggering technique takes into account the individual differences of patients ,so the patient's delay scan time can be evaluated better and higher quality of lower extremity arterial images can be acquired .

Objective To analyze the clinical characteristics and drug resistance of 57 patients with Salmonella infection, and to understand the sensitivity of Salmonella to commonly used antibiotics. Methods Clinical data of 57 Salmonella infection patients admitted in our hospital from January 2016 to February 2019 were collected. After hospitalization, routine examinations such as hematuria and stool were carried out, and fecal bacterial culture and drug sensitivity tests were performed. Results Among the 57 patients, the highest incidence of clinical symptoms was abdominal pain and diarrhea (57 cases, 100%), with an average of 7.46±2.03 times. The others were nausea and vomiting (45 cases, 78.95%), fever (43 cases, 75.44%), headache (34 cases, 59.65%), tenesmus (26 cases, 45.61%) and dehydration (25 cases, 43.86%). The results of stool routine examination showed that 51 cases (89.47%) were positive for fecal leukocytes and 45 cases (78.95%) were positive for fecal occult blood test. The results of urine routine test showed that 45 cases (78.95%) were positive for proteinuria and 38 cases (66.67%) for occult blood test. The results of blood routine examination showed that the average value of leukocyte count was (9.98±4.22)×10⁹/L, neutrophils accounted for 79%, and C-reactive protein was (60.15±32.48)mg/L. The results of drug sensitivity showed that the resistant strains to cephalosporins and quinolones accounted for a large proportion of the total strains. Conclusion The main symptoms of Salmonella infection in this area were abdominal pain and diarrhea. Fecal examination and routine urine examination were more valuable for diagnosis. The detection of resistance to quinolone and cephalosporin antibiotics should be strengthened to provide a basis for rational use of drugs.

Objective : To used Toll⁃like receptor 4( TLR4) inhibitor ( TAK⁃242) investigate the role of TLR4 in the early stage of acetaminophen (APAP) Ⅳinduced acute liver injury in mice. Methods : Fifty⁃eight male institute of cancer research( ICR) mice were randomly divided into control group ( normal control group , solvent control group , inhibitor control group) and experimental group (APAP 4 ⁃ hour group , APAP + TAK⁃242 4 ⁃ hour group , APAP 12 ⁃ hour group , APAP + TAK⁃242 12 ⁃ hour group) . Mice in the experimental group were given a single dose of APAP (300 mg/kg) and TAK⁃242 (3 mg/kg) were given intraperitoneal injection 3 ⁃ hour before APAP injection. The serum alanine aminotransferase (ALT) level and liver index of mice in each group were compared ; HE staining showed pathological changes of liver tissue;the level of high mobility group box⁃1 (HMGB1) was determined by immunohistochemistry;the levels of TLR4 , HMGB1 and nuclear factor kappa B(NF⁃κB) protein were detected by Western blot;the levels of monocyte chemoattractant protein⁃1( MCP⁃1) , interleukin( IL) Ⅳ1β , tumor necrosis factor⁃α ( TNF⁃α ) and IL⁃6 genes were determined by real⁃time fluorescence quantitative PCR ( RT⁃qPCR) . The content of IL⁃6 in liver tissue was determined by enzyme linked immunosorbent assay (ELISA) . Results : HE staining showed liver tissue of mice obvious swelling and congestion of in APAP group at 4 ⁃hour and typical lobular central necrosis in APAP group at 12 ⁃ hour;the degree of liver necrosis in APAP + TAK⁃242 groups at 4 ⁃ hour and 12⁃ hour was less than that in APAP group at the same time point. Compared with the normal control group , serum ALT level , liver index , TLR4 , HMGB1 , NF⁃κB protein content , MCP⁃1 , IL⁃1β , TNF⁃α , IL⁃6 gene levels and IL⁃6 content in liver tissue of APAP 4 ⁃ hour group increased ; serum ALT level , liver index , HMGB1 protein content and IL⁃6 content in liver tissue increased in APAP 12 ⁃ hour group. Compared with APAP 4 ⁃ hour group , serum ALT level , liver index , TLR4 , HMGB1 , NF⁃κB protein content , MCP⁃1 , IL⁃1β , TNF⁃α , IL⁃6 gene level and IL⁃6 content in liver tissue decreased in APAP + TAK⁃242 4 ⁃ hour group. Compared with APAP 12 ⁃hour group , the levels of TLR4 , HMGB1 protein and MCP⁃1 , IL⁃1β , TNF⁃α genes in APAP + TAK⁃242 12 ⁃ hour group decreased. Conclusion nhibition of TLR4 may inhibit TLR4/HMGB1 pathway to reduce the inflammatory response in the early stage of acetaminophen⁃induced acute liver injury in mice.

Objective To investigate the MRI features of primary retroperitoneal leiomyosarcoma(PRLS).Methods Thirty-three cases of pathologically confirmed PRLS were analyzed retrospectively,and their multi-parameter MRI features were analyzed qualitatively and quantitatively.Results Of the 33 PRLS,24 cases were located in the renal hilum,inferior vena cava,or the area around the bifurcation of the iliac vessels.Twenty-four cases had relatively intact capsule,25 cases had necrosis,and 15 cases had coagulated geographic necrosis.The mean diameter of the tumors was(9.9±5.1)cm,ranging from 3.0 to 20.7 cm,among which 27 cases with a diameter larger than 5 cm.The tumor parenchyma of the 33 PRLS all showed significantly high signal intensity on diffusion weighted imaging(DWI),and significantly low signal intensity on apparent diffusion coefficient(ADC)map.The tumor parenchyma showed moderate to obvious degree of progressive enhancement,and the signal intensity value of the tumor in each phase after contrast injection was higher than that of the psoas major muscle(P＜0.001).Conclusion PRLS are usually large but have a relatively intact capsule and are closely related to the major retroperitoneal veins.The coagulated geographic necrosis,significantly limited diffusion of water molecules,and progressive enhancement pattern all show certain MRI characteristics.

Objective To investigate whether Toll-like receptor 4 (TLR4) inhibition affects liver regeneration during acetaminophen (APAP)-induced liver injury in mice, as well as the mechanism of TLR4 involved in liver regeneration. Methods A total of 78 male CD-1 mice were divided into nine groups using a random number table, i.e., three control groups (normal control group, solvent control group, inhibitor control group) with 6 mice in each group and six experimental groups (APAP 24-hour group, TAK-242+APAP 24-hour group, APAP 48-hour group, TAK-242+APAP 48-hour group, APAP 72-hour group, TAK-242+APAP 72-hour group) with 10 mice in each group. The mice in the experimental groups were given a single dose of intraperitoneally injected APAP (300 mg/kg), and TAK-242 was intraperitoneally injected at a dose of 3 mg/kg at 3 hours before APAP administration. Serum and liver tissue samples were collected at different time points. The biochemical method was used to measure the serum level of alanine aminotransferase (ALT); HE staining was used to observe liver pathological changes; RT-PCR, Western blot, and immunohistochemistry were used to measure the expression levels of Cyclin D1, PCNA, Ki-67, STAT3, and p-STAT3. The t -test was used for comparison of normally distributed continuous data between two groups; a one-way analysis of variance was used for comparison between multiple groups, and the least significant difference t -test was used for further comparison between two groups. The Mann-Whitney U test was used for comparison of non-normally distributed continuous data between two groups, and the Kruskal-Wallis H test was used for comparison between multiple groups and further comparison between two groups. Results Compared with the normal control group, the APAP 24-hour and 48-hour groups had a significantly higher serum level of ALT (both P < 0.05), and the TAK-242+APAP 24-hour and 48-hour groups had a significantly higher serum level of ALT than the APAP group at the same time point (both P < 0.05). HE staining showed typical central lobular necrosis in the liver of APAP-treated mice, and the TAK-242+APAP 24-hour and 48-hour groups had a significantly larger necrotic area than the APAP group at the same time point (both P < 0.05). RT-PCR, Western blot, and immunohistochemistry showed that the TAK-242+APAP 24-hour, 48-hour, and 72-hour groups had significantly lower mRNA and protein expression levels of Cyclin D1 than the APAP group at the same time point (all P < 0.05); the TAK-242+APAP 24-hour, 48-hour, and 72-hour groups had a significantly lower mRNA expression level of PCNA than the APAP group at the same time point (all P < 0.05), and the TAK-242+APAP 24-hour and 48-hour groups had a significantly lower protein expression level of PCNA than the APAP group at the same time point (all P < 0.05); the TAK-242+APAP 24-hour and 72-hour groups had a significantly lower mRNA expression level of Ki-67 than the APAP group at the same time point (all P < 0.05), and the TAK-242+APAP 24-hour, 48-hour, and 72-hour groups had a significantly lower protein expression level of Ki-67 than the APAP group at the same time point (all P < 0.05). In addition, the TAK-242+APAP 24-hour and 48-hour groups had a significantly lower phosphorylation level of STAT3 than the APAP group at the same time point (both P < 0.05). Conclusion TLR4 may promote liver regeneration by increasing the phosphorylation level of STAT3 during APAP-induced liver injury in mice.

【Objective】 To develop and verify a kinetic method for the determination of prekallikrein activator (PKA) content. 【Methods】 The optimal reaction conditions were determined by comparing the factors of pH and ionic strength of different sample dilution buffers, incubation time of each procedure, and incubation temperature. The accuracy, specificity, precision, linearity, stability and durability of the method were validated. 【Results】 The sample was diluted with 0.05 mol/L Tris-HCl buffer (pH8.5, containing 0.15 mol/L NaCl) and incubated by prekallikrein (PK) at 37℃ for 20 min. After that, the substrate S-2302 was added. Within 10 min before the measurement, the absorbance change rate reached △A405/min. The validation results indicated that the linear range of the method was (0.5~4.0)IU/mL, while the recovery of calibration standard was 96.9%~103.7% with the R² value more than 0.99. The specificity test showed that human serum albumin, excipients of intravenous human immunoglobulin (pH4), low pH and protein content had no significant effect on the detection of PKA, The recovery rates of standard sample solution in the specificity experiment were 98.0% (0.9% sodium chloride solution), 95.3% (0.46% sodium caprylate solution), 96.7% (10% maltose solution, pH4.0), 94.0%(20%BSA), and 94.0%(5%BSA, pH4.0), respectively. The accuracy and precision of the method can meet requirements in the range between 0.5 and 4.0 IU/mL. The inter-batch recovery rate of quality control samples were between 96.4%~109.5% with the coefficients of variation(CV) between 0.2%~6.9%, while the intra-batch recovery rate were between 101.5%~102.9% with the CV between 2.6%~5.9%. The linearity, accuracy and precision of the assay can meet the requirements when PK and S-2302 were placed at room temperature for less than 6 hours, with the recovery rate of quality control samples between 94.9%~109.9%. The end-point method and kinetic method were used to determine the PKA in 20 batches of human serum albumin, and the consistency showed that there was no significant difference between the two methods(P>0.05). 【Conclusion】 A kinetic method for determination of PKA content with good linearity, specificity, accuracy, precision, stability and durability has been established. Compared with the method in ChP, the new method is more convenient, accurate and rapid to determine the content of PKA in human albumin and human immunoglobulin (pH4) for intravenous injection.