Objective To compare with the advantage or shortage of several scan series in imaging of normal articular cartilage in knee.The MR manifestation were observed and thickness of different location of cartilage in knee in different series were calulated.Methods The knees of 30 healthy volunteers were imaged with five different MR imaging sequences including T 1-weighted,proton density-weighted,T 2-weighted FSE,STIR and 3D-FS-SPGR.The value of CNR were determined for cartilage versus a saline fluid phantom,marrow fat,and muscle.The MR 2D and 3D manifestation were observed and thickness of different location of cartilage in knee in different series were calculated.Results The value of CNR of 3D-FS-SPGR for cartilage versus a saline fluid phantom,marrow fat,and muscle were compared with other sequences and were significantly different.The values of cartilage thickness with 3D-FS-SPGR were more than those with other series.The mulplaner appearance was observed.There was five-plane manifestation when cartilage thickness was more than 4 mm.The value of cartilage thickness of male and female were 2.63 mm and 2.52 mm,respectively.Conclusion 3D-FS-SPGR sequences have significant advantage compared with other series in imaging normal articular cartilage of knee.The cartilage is show clearly than other sequences.The value of cartilage thickness with 3D-FS-SPGR is more accurate.Moreover it can also provide much information adding to 3D construction of cartilage.

Objective To recognize CT signs of parapharyngeal space (PPS) changing in nasopharyngeal carcinoma (NPC) further.Methods 30 patients with proven NPC by biopsy were performed CT and MR scanning before radiotherapy. Results According to CT findings,four types of PPS display in 30 cases were found,each of which was observed and compared with MR findings and were as follows: (1)PPS ,which had no changing on CT, showed fat-filled triangular space continuously on MRI. (2) PPS, which became narrow and linear hypodense on CT,showed that fat intensity was pressed, but continuously on MRI; (3) PPS, which became narrow and linear hyperdense on CT,showed fat intensity,was pressed exceedingly but continuously either on MRI. (4)PPS,which was diminished on CT, showed the mass occupied PPS and lateral pterygoid muscles was pushed, medial fatty space of which was diminished, but intensity of medial or lateral pterygoid muscles was normal or abnormal on MRI. Conclusion (1)When PPS becomes narrow on CT,whether PPS shows hyperdense or hypodense,the mass makes a breakthrough PPS. (2) When PPS is diminished completely on CT,the mass steps PPS to the infratemporal fossa.

Objective To explore the feasibility of using glycophorin A somatic mutation in peripheral erythrocytes,in order to evaluate the cancer risk of occupational medical exposure to ionizing radiation.Methods Totally 336 medical radiation workers were recruited as three groups (general radiation group,computer tomography group,intervention and radiation treatment group) and 112 healthy adults were selected as control by using stratified random cluster sampling method,where 176 medicalradiation workers and 58 health controls had a MN-heterozygous type.The erythrocytes were fixed and bound with fluorescent-labeled monoclonal antibody,and the glycophorin A somatic mutation frequency was assayed by a modified BR6-1W1 method using a FACScan flow cytometer.The individual susceptibility to radiation was investigated using micronuclei test and 3-Aminobenzamide index test.Results The GPA somatic mutation frequency of medical-radiation workers was significantly higher than that of healthy control ( t =2.29 - 11.48,P ＜ 0.05 ).In particular,the NO GPA aberration frequency of interventional radiology workers was much higher than that of the general medical diagnostic workers (t =2.01,P ＜ 0.05).In addition,the NO GPA variant frequency changed significantly with the years of radiation service,cumulative doses,and 3AB index.However,the NN GPA variant frequency was only associated with the years of radiation service,and no significant correlations were found between NN GPA variant frequency and cumulative dose of radiation exposure or 3AB index. Conclusions GPA mutation frequency,especially NO GPA mutation frequency could be used as a sensitive biomarker to predict the DNA damage and individual susceptibility for the population exposed to professional low-dose ionizing radiation.

Objective To establish the pipeline and evaluate the feasibility of high-throughput sequencing method used in the detection of severe pneumonia pathogens.Methods Clinical control study was used.Bronchi alveolar lavage fluids (BALF) samples from 76 patients with severe pneumonia (treatment group) and 18 patients with tracheal malacia (control group) and without clinical detected pathogens were collected during March 2015 to December 2016 in Shenzhen Children′s Hospital.The pathogens in the samples were detected using clinical tests and high-throughput sequencing respectively.The results of high-throughput sequencing were confirmed by real-time quantitative PCR and the high-throughput sequencing method used in the detection of severe pneumonia pathogens was evaluated.The χ2 test was used to analyze the correlation of detection rate between the high-throughput sequencing group and the non high-throughput sequencing group.Results The pipeline and method of high-throughput sequencing used in the severe pneumonia pathogens detection was established.The pipeline included sample collection, DNA extraction, library construction, sequencing, and bioinformatic analysis.In 76 cases of patients with severe pneumonia, the results of high-throughput sequencing in 66 cases of bronchoalveolar lavage fluid specimens were positive.The sensitivity was 86.84%, which was significantly higher than the total sensitivity of traditional clinical detection methods including bacterial culture, immunofluorescence and quantitative PCR(68.42%,52/76),χ2=7.426,P<0.001.A total of 13 pathogens were detected in 66 positive samples of high-throughput sequencing, including Mycoplasma pneumoniae, Streptococcus pneumoniae, Haemophilus influenzae and adenovirus, etc.Nine kinds of pathogens were detected in these samples through non-high-throughput sequencing.In the experimental group, the results obtained by clinical test and high-throughput (80.26%) were entirely consistent in 61 samples and not completely consistent in 15 samples (19.74%) specimens.These inconsistent results were mainly concentrated in the detection of adenovirus, Streptococcus pneumoniae and Haemophilus influenzae through high-throughput sequencing, whereas clinical cultures and immunofluorescence methods were not able to detect these pathogens.PCR validation showed that there was no significant difference between the results of high-throughput sequencing and the PCR tests (χ2=0.517,P=0.472), and the difference between the results of high-throughput sequencing and traditional clinical detection methods was statistically significant (χ2=11.671,P<0.001).Conclusion The method for the detection of severe pneumonia pathogens based on high-throughput sequencing is highly sensitive and can detect unknown pathogens, which is superior to those used in traditional clinical detection.

Objective To understand the epidemiological characteristics, genomic variations and macrolide resistance of Bordetella pertussis ( B. pertussis) strains circulating in Shenzhen with clinical data analysis, genotype profiling, phylogenetic analysis and antimicrobial susceptibility test. Methods Clinical data of patients with pertussis in Shenzhen Children's Hospital were collected from the electronic medical re-cord system. Genome sequences of 31 B. pertussis isolates were analyzed with next-generation sequencing and de novo assembled. Multilocus sequence typing (MLST) was performed to identify their sequences types. Sequence alignment by BLASTn was used to identify virulence genotypes and mutations in 23S rRNA gene. A phylogenetic tree was constructed to analyze the relationships among them. E-test was used to identify ma-crolide resistance. Results All of the 31 B. pertussis strains were identified as sequence type-2 (ST-2) by MLST with diverse virulence genotypes. Two were prn-deficient strains. Based on the phylogenetic tree, all of the isolates were distant from vaccine strains. Nineteen isolates were resistant to erythromycin with A2047G mutation in 23S rRNA. Conclusions The virulence genotypes of B. pertussis strains in Shenzhen were diverse with increasing non-vaccine genotypes. Macrolide-resistant strains were prevalent. This study might provide reference for improving the prevention, management and vaccination strategy of pertussis.

Objective:To compare carotid endarterectomy (CEA) and carotid artery stenting (CAS) in perioperative, medium and long term prognosis of patients with carotid artery stenosis.Methods:A retrospective analysis was performed on 1 329 cases of carotid artery stenosis treated at Department of Vascular Surgery, Beijing Anzhen Hospital from Jan 2011 to Aug 2020, as all cases being divided into CAS group and CEA group.Results:There were significant differences in age ( t=0.098, P=0.023) and drinking habits ( χ2=8.055, P=0.005) between the two groups. There were more unstable plaques in CEA group ( χ2=4.392, P=0.038), and more bilateral lesions in CAS group ( χ2=9.673, P=0.038). In perioperative period, there were more mannitol use in CEA group ( χ2=78.614, P<0.001), more incision/puncture site complications ( χ2=5.158, P=0.035), lung infection ( χ2=6.355, P=0.013), cerebral hyperperfusion syndrome (CHS) ( χ2=5.158, P=0.035) and extracranial nerve injury ( χ2=23.760, P<0.001) in CEA group than in CAS group, and more acute renal failure in CAS group ( χ2=10.393, P=0.001). There was no significant difference in survival rate and ischemic stroke, myocardial infarction, cerebral hemorrhage and renal insufficiency between the two groups (all P>0.05). The mean survival time of CAS group was 53.195 months (95% CI: 52.040-54.350), and 54.492 months (95% CI: 53.790-55.195) in CEA group ( P=0.051). Conclusions:Patients in CEA group had more unstable plaque and a lower perioperative stroke rate. CEA group had higher risk of CHS,while CAS was with lower postoperative lung infection rate and less wound local complications. There was no significant difference in long-term survival between the two groups.