Purpose To compare radiation dose and image quality of different scan modes for CT pulmonary angiography (CTPA) including high-pitch flash mode, dual energy CT (DECT) mode, 128-slice mode of dual source CT and 64-slice CT mode. Materials and Methods One hundred and sixty-seven patients with suspected pulmonary embolism were retrospectively studied. All the patients underwent CTPA. Twenty patients were selected randomly from the patients scanned by high-pitch flash mode. Patients who were scanned by the other three modes were selected with body mass index and age matched those in high-pitch flash mode, with 20 patients in each group. Two radiologists assessed signal-to-noise ratio (SNR) and image quality with 5-piont scale. Dose parameters of volume CT dose index (CTDIvol), dose length product (DLP), and effective dose (ED) were compared among the four groups. Results Mean CTDIvol, DLP and ED were (3.72±0.74) mGy, (137.5±28.7) mGy · cm, and (2.34±0.41) mSv for Flash mode;(5.31±1.21) mGy, (181.6±34.5) mGy· cm and (3.24±0.57) mSv for DECT mode;(5.66±1.47) mGy, (198.7±42.1) mGy·cm and (3.58±0.63) mSv for 128-CT mode;and (6.75±1.68) mGy, (231.5±54.2) mGy·cm and (4.21±0.89) mSv for 64-CT mode. There was no significant difference of SNR and image quality among the four modes (P>0.05). Conclusion There are no significant difference of image quality among the four groups. Flash mode allows for minimum radiation dose compared to other modes. DECT mode and 128-CT mode get higher radiation dose with no difference between them. 64-CT mode gets the highest radiation dose.

To analyze the mutations of F12 genein one pedigree with congenital factor FXII (FXII) deficiency , and investigatethe molecular mechanisms of FXII deficiency . Methods Activated partial thromboplastin time(APTT),Prothrombin time(PT), FXII activity(FXII:C), FXII antigen(FXII:Ag) and other coagulant parameters were tested in the proband and his family members .5'and 3'UTR,all exons and their exon-intron boundaries of F12 gene were analyzed by direct sequencing .The detected mutations were confirmed by reverse sequencing .100 healthy persons were as normal controls .Results The proband showed a markedly prolonged APTT (106.4s), the FXII:C and FXII:Ag were 2.0% and 1.0%, respectively .Hissecond daughter and granddaughter had slightly prolonged APTT , and other family members are normal.The FXII:C and FXII:Ag of family members were also decreased ( his son, 23.0% and 21. 0%;his elder daughter , 23.0%and 23.0%;his second daughter ,24.0%and 23.0%;hisgranddaughter , 23.0%and 23.0%).The phenotype of all members is consistent with cross -reactive material negative . Nucleotide sequencing analysis showed that the proband had missense mutations in the F 12 gene, including one homozygous mutationc.1556T >G ( p.Leu519Arg) and a commonly reported single nucleotide polymorphism site within the promoter region of the F 12 gene (46T/T) .Sequencing results from the proband 'children demonstrate them as carriers of a heterozygous missense mutation .The proband 's wife is normal and with 46C/C in the promoter region .Conclusion The c.1556T>G in exon 13 is a novel mutation .This mutation affects FXIIcatalytic function , associated with a reduced level of FXII .

Objective:To study the distribution and antibiotics resistance of the main pathogens of neonatal purulent meningitis in different regions of China.Methods:A retrospective descriptive clinical epidemiological study was conducted in children with neonatal purulent meningitis which admitted to 18 tertiary hospitals in different regions of China between January 2015 to December 2019. The test results of blood and cerebrospinal fluid, and drug sensitivity test results of the main pathogens were collected. The distributions of pathogenic bacteria in children with neonatal purulent meningitis in preterm and term infants, early and late onset infants, in Zhejiang Province and other regions outside Zhejiang Province, and in Wenzhou region and other regions of Zhejiang Province were analyzed. The chi-square test was used for statistical analysis.Results:A total of 210 neonatal purulent meningitis cases were collected. The common pathogens were Escherichia coli ( E. coli)(41.4%(87/210)) and Streptococcus agalactiae ( S. agalactiae)(27.1%(57/210)). The proportion of Gram-negative bacteria in preterm infants (77.6%(45/58)) with neonatal purulent meningitis was higher than that in term infants (47.4%(72/152)), and the difference was statistically significant ( χ2=15.54, P=0.001). There were no significant differences in the constituent ratios of E. coli (36.5%(31/85) vs 44.8%(56/125)) and S. agalactiae (24.7%(21/85) vs 28.8%(36/125)) between early onset and late onset cases (both P>0.05). The most common pathogen was E. coli in different regions, with 46.7%(64/137) in Zhejiang Province and 31.5%(23/73) in other regions outside Zhejiang Province. In Zhejiang Province, S. agalactiae was detected in 49 out of 137 cases (35.8%), which was significantly higher than other regions outside Zhejiang Province (11.0%(8/73)). The proportions of Klebsiella pneumoniae, and coagulase-negative Staphylococcus in other regions outside Zhejiang Province (17.8%(13/73) and 16.4%(12/73)) were both higher than those in Zhejiang Province (2.9%(4/137) and 5.1%(7/137)). The differences were all statistically significant ( χ2=14.82, 12.26 and 7.43, respectively, all P<0.05). The proportion of Gram-positive bacteria in Wenzhou City (60.8%(31/51)) was higher than that in other regions in Zhejiang Province (38.4%(33/86)), and the difference was statistically significant ( χ2=6.46, P=0.011). E. coli was sensitive to meropenem (0/45), and 74.4%(32/43) of them were resistant to ampicillin. E. coli had different degrees of resistance to other common cephalosporins, among which, cefotaxime had the highest resistance rate of 41.8%(23/55), followed by ceftriaxone (32.4%(23/71)). S. agalactiae was sensitive to penicillin, vancomycin and linezolid. Conclusions:The composition ratios of pathogenic bacteria of neonatal purulent meningitis are different in different regions of China. The most common pathogen is E. coli, which is sensitive to meropenem, while it has different degrees of resistance to other common cephalosporins, especially to cefotaxime.