Objective To investigate the effect of different radiation doses on the accuracy of iodine quantification and CT value of virtual monochromatic image with a muti-spectral CT iodine phantom using second-generation dual-layer detector spectral CT(DLCT).Methods The second-generation DLCT scan abdominal phantom was used,which consisted of six different concentrations of iodine rods at 4,8 and 12 g/L.The scan parameters were set at 100,120 and 140 kVp tube voltages,and six radiation exposure sequences were scanned at each tube voltage:5,10,15,20,25 and 30 mGy.Measure the iodine concentration value and the CT value at the single level of 50,70 and 100 keV,and calculate the absolute error value of iodine concentration and CT value under different radiation exposure.SPSS 22.0 software single factor analysis of variance was used to compare the difference between the io-dine concentration and the absolute error of CT value under different Radiation exposure,and LSD method was used to compare the two groups.Results The absolute error of CT value of 4 g/L iodine rod with 10～30 mGy scanning at 100 keV energy level was significantly higher than that of 12 g/L and 8 g/L(P＜0.05),and the absolute error of iodine concentration measurement of other iodine rods with different concentrations at different Radiation exposure had no statistical difference.Conclusions The second-generation double-layer detector spectral CT has high meas-urement stability for iodine concentration quantification and CT value accuracy under conditions of radiation dose greater than 5 mGy.

Objective:To investigate the feasibility of coronary CT angiography(CCTA)-feature tracking(FT) for assessing global and regional myocardial strain in patients with heart failure(HF).Methods:From July 2019 to December 2020, twenty-five patients diagnosed with HF from Peking Union Medical College Hospital were prospectively enrolled into the study. All patients underwent retrospective electrocardiogram-gated CCTA and cardiac MR (CMR) imaging within 7 days. CCTA-FT and CMR-FT were undertaken using cvi 42 dedicated commercial software to measure global and regional strain parameters, including global peak radial strain (GPRS), global peak circumferential strain (GPCS) and global peak longitudinal strain (GPLS), as well as peak radial strain (PRS), peak circumferential strain (PCS) and peak longitudinal strain (PLS) of left ventricular basal segment, middle segment and apical segment. Conventional left ventricular functional parameters were also calculated, including left ventricular ejection fraction (LVEF), left ventricular stroke volume (LVSV) and left ventricular mass index (LVMI). Paired t test or Wilcoxon signed-rank test was used to compare the differences of measurements between CCTA group and CMR group. Pearson or Spearman correlation analysis was used to analyze the correlation between the two groups. Inter-and intra-observer consistence in CCTA group was evaluated by intraclass correlation coefficient (ICC) analysis. Results:The effective radiation dose of CCTA examination was 6.00 (4.86,7.63) mSv. Inter-and intra-observer consistence in CCTA group was excellent, and the ICC value was 0.85-0.98. In the overall strain parameters, GPCS in CCTA group[-8.10%(-10.32%, -5.20%)] was significantly lower than that of CMR group[-8.49%(-13.79%, -5.95%)] ( Z=-2.15, P=0.031). There was no significant difference in GPRS and GPRS between the two measurement methods ( P>0.05). Strong correlations were observed between GPRS, GPCS and GPLS ( r=0.65, 0.63, 0.71,all P<0.001). For local strain parameters, PCS in the middle segment and apical segment of CCTA group were lower than those of CMR group ( Z=-2.17, -2.62, all P<0.05). There were no significant differences in PCS of basal segment, PRS and PLS of all segments between groups (all P>0.05). The PCS and PLS of basal segment, PRS of middle segment and PRS of apical segment were moderately correlated ( r=0.46, 0.52, 0.58, 0.53, P<0.05); The other local strain parameters were strongly correlated, the range of r value was from 0.64 to 0.70 (all P<0.001). For left ventricular functional parameters, LVEF, LVSV and LVMI showed no significant differences between groups ( P>0.05), and the correlation was extremely strong ( r=0.90, 0.89, 0.96, all P<0.001). Conclusions:The repeatability of CCTA-FT technique in measuring myocardial strain was good, and the correlation of parameters measured by CCTA-FT technique and CMR-FT technique was excellent. Therefore, CCTA-FT technique can be used as a new noninvasive and simple method to evaluate myocardial motor function.

Objective:To explore the feasibility in evaluating segmental extracellular volume (ECV) using dual-layer spectral detector CT in patients with heart failure with various percentages of delayed hyper-enhanced volume, using MRI as a reference.Methods:Twenty-seven patients with heart failure in Peking Union Medical College Hospital were prospectively enrolled in this study from July 2019 to January 2021. All the patients underwent both CT late iodine enhancement and MR late gadolinium enhancement imaging within a week. According to percentages of hyper-enhanced volume on cardiac MR image, myocardial segments were classified into 3 groups: 0-4% (group A), 5%-49% (group B) and 50%-100% (group C). ECV images were independently observed by 2 experienced radiologists. The correlation and agreement between CT-ECV and MRI-ECV for the whole myocardial assessment and for the segmental assessment were evaluated using Spearman correlation and Bland-Altman analysis. Inter-observer agreement was assessed using the ICC.Results:Of the 27 patients, 432 segments were analyzed, with 199 segments in group A, 151 segments in group B and 82 segments in group C. In the whole myocardial analysis, the CT-ECV and MRI-ECV were 32.25% (28.04%, 34.28%) and 32.27% (28.35%, 34.77%), respectively. A good correlation was found between CT-ECV and MRI-ECV ( r=0.969, P<0.001). Bland-Altman analysis between CT-ECV and MRI-ECV showed a small bias (0.4%), with 95% limits of agreement of -6.9% to 7.8%. as for the segmental myocardial assessment, the CT-ECV was 28.23% (26.18%, 29.92%) for group A, 33.29% (30.16%, 35.96%) for group B and 40.22% (34.06%, 46.70%) for group C. There was statistically significant difference in ECV among three groups (all P<0.001). Good correlations between CT-ECV and MRI-ECV were found in group A ( r=0.614, P<0.001), group B ( r=0.852, P<0.001) and group C ( r=0.953, P<0.001). Bland-Altman analysis between CT-ECV and MRI-ECV showed a small bias 2.0% (95% limits of agreement:-17.6%-21.6%) in group A, a small bias -0.4% (95% limits of agreement: -13.8%-12.9%) in group B and a small bias -1.8% (95% limits of agreement: -17.4%-13.9%) in group C. The ICC values between 2 observers were 0.877 and 0.945 on CT-ECV and MRI-ECV, respectively. Conclusions:The larger percentage of hyper-enhanced volume on cardiac MR image, the stronger correlation are between the CT-ECV and MRI-ECV. CT-ECV may be taken as an alternative tool for quantitative evaluation of myocardial tissue in patients with heart failure.

Objective:To explore the clinical effect of Bobath manipulation combined with traditional Chinese medicine fumigation and intradermal acupuncture on shoulder hand syndrome(SHS) after stroke.Methods:From April 2017 to August 2019, 80 patients with SHS after stroke admitted to the People's Hospital of Deqing County were selected, and they were divided into control group and observation group according to the random digital table method, with 40 cases in each group.The control group was treated by Bobath therapy, and the observation group was treated by Bobath therapy combined with acupuncture(intradermal acupuncture) and traditional Chinese medicine fumigation.After 8 weeks of treatment, the ROM scale, FMA scale, BI scale and VAS scores were used to evaluate the improvement in the mobility of the shoulder and wrist joints, motor function of the upper limbs, quality of life and pain, and the clinical efficacy of the two groups was compared.Results:Compared with before treatment, the ROM scale score of all dimensions of shoulder and wrist mobility, FMA scale score and BI scale score of all patients after treatment increased significantly, and the VAS score decreased significantly, the differences were statistically significant(all P<0.05). Compared with the control group after treatment, the improvement of the indicators mentioned above of the observation group were better[shoulder joint flexion ROM score: (154.83±25.63)points vs.(133.82±22.03)points; shoulder joint abduction ROM score: (152.36±25.68)points vs.(133.35±19.96 )points; shoulder joint external rotation ROM score: (75.87±14.69)points vs.(60.82±16.57 )points; wrist joint palm flexion ROM score: (73.94±14.37)points vs.(57.37±9.47)points; wrist joint back extension ROM score: (60.83±7.61)points vs.(42.27±6.37 )points; FMA scale score: (45.74±6.82)points vs.(34.19±4.07)points; BI scale score: (70.36±12.09)points vs.(58.70±12.53)points; VAS score: (1.05±0.49)points vs.(3.37±1.14)points, t=3.703, 3.715, 3.257, 5.576, 7.964, 3.037, 8.746, 3.153, all P<0.05]. The total effective rate of the observation group was significantly higher than that of the control group[97.5%(39/40) vs.62.5%(25/40), χ 2=15.313, P<0.05)]. Conclusion:The combination of Bobath therapy with traditional Chinese medicine fumigation and intradermal acupuncture can improve the pain degree, joint mobility disorder, upper limb motor function and quality of life of SHS patients, the efficacy is better than single Bobath therapy.The clinical effect is accurate, and it is worthy of further promotion and application.

Objective:To evaluate the feasibility of high concentrated contrast media combined with monochromatic images to improve image quality with double low scanning in dual-layer spectral coronary CT angiography.Methods:Fifty-six patients with suspected coronary artery disease were enrolled and randomly separated into two groups. All patients were scanned at 120 kVp in step-and-shoot mode using a dual-layer detector CT (IQon spectral CT). Patients were either injected with 18 ml high concentration contrast medium(400 mgl/ml) at 2 ml/s (group A) or 45 ml contrast medium (370 mgl/ml) at 4 ml/s (group B). Forty to 80 keV monoenergetic images with 10 keV increment and conventional image (group A2) were reconstructed for group A, conventional poly-energetic image was reconstructed for group B. Region of interest was placed on aorta root (AO), middle segment of left anterior descending (LAD), left circumflex (LCX) and right coronary artery (RCA) to measure the attenuation and noise, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). Image quality was assessed by two reviewers independently with a 4-point scale on image quality (1-undiagnostic,4-excellent). The objective and subjective image evaluation were compared using the Kruskal-Wallis test. The Steel Dwass was used for multiple comparisons between monoenergetic images in Group A and conventional images in Group B, after the Kruskal-Wallis test.Results:There were significant differences among the attenuation, noise, SNR and CNR of group B, group A2, and monoenergetic images(all P<0.001).The CT value in the aortic root was significantly higher at 40-50 keV monoenergetic images than that in group B(all P<0.05), and similarly, the CT value in LAD,LCX and RCA at 40 keV were superior than that in group B(all P<0.001). There was no significant difference in the noise of the aortic root among 40 keV image, group A2 and group B(all P>0.05),while the noise in the 50-80 keV monoenergetic images were significantly lower than that in Group B(all P<0.001). The SNR and CNR in the aortic root were significantly higher at 40-60 keV monoenergetic images than that in group B(all P<0.001).The SNR in LAD and RCA at 40，50 keV and the CNR in LAD and RCA at 40-60 keV were higher than that in group B(all P<0.01).The SNR at 40-60 keV and CNR at 40-70 keV in LCX were superior than that in group B(all P<0.05). There were significant differences among the subjective image quality score of group B, group A2, and monoenergetic images(all P<0.001).The subjective image quality score of 40，50 keV images were not significantly different from that in group B (all P>0.05),while the score in 60-80 keV image and group A2 were lower than that of Group B(all P<0.001). Conclusion:40，50 keV low monochromatic images derived from dual-layer spectral detect CT combined with high concentrated contrast media can provide comparable or superior image quality with double low scanning in CCTA study.

Caliciviridae Infections ; prevention & control ; therapy ; Disease Outbreaks ; prevention & control ; Humans ; Norovirus ; Practice Guidelines as Topic

Objective To investigate the changes and clinical significance of the frequency of circulating CD4+ CD25+ regulatory T cells (Treg) in nonalcoholic fatty liver (NAFL) patients.Methods CD4+ CD25+ Treg in the peripheral blood from 50 NAFL patients and 50 healthy subjects were quantitatively analyzed using flow cytometry. Group t test or Mann-Whitney U test and Spearman's rank correlation test were used for statistical analysis.Results The proportion of circulating CD4+CD25+ Treg in NAFL patients was (5.39 ± 1.94)％,which was significantly higher than that in healthy controls [(4.21±1.52)％](t=3.385,P＜0.01).Further analysis revealed that the frequency of Treg was positively correlated with triglyceride (TG) level and body mass index (r=0.307 and 0.251,respectively; P=0.002 and 0.012,respectively),and negatively correlated with high density lipoproteincholesterol (HDL-C) (r=-0.306,P=0.002).Meanwhile,Treg in patients with high body mass index,high TG,low HDL-C,hypertension and metabolic syndrome (MS) were all higher than those in controls (t=2.294,2.533,3.154,2.010 and 4.454,respectively; all P＜0.05).But there was no significant difference between patients with high fasting blood glucose and controls (U=1143.500,P=0.471).Conclusion The increased frequency of peripheral Treg in NAFL patients may have some relations with the imbalance of proinflammation and anti-inflammation in NAFL patients who coexisting with MS.

Objective To study on plasmid-mediated quinolone-resistant in Escherichia coli strains isolated from fecal samples of chicken and swine from the nine farms around our country.Methods Antimi-crobial susceptibility testing was carried out by broth microdilution testing,gyrA,gyrB,parC,qnr and aac (6')- Ⅰ b-cr were examined by PCR,and the products were sequenced.Conjugation experiment was carried out to proved that the plasmid-mediated quinolone resistance was transferable.Results In the total 818 animal isolates,qnr and aac genes were detected in 38 (4.6%) and 75 (9.2%) strains.The qnrA,qnrB,and qnrS genes were detected in 1 (0.1%),9 (1.1%) and 28 (3.4%) of the isolates.All isolates were negative for qnrC,qnrD genes.Conclusion There is a close relationship between high level quinolone resistance and plasmid-mediated quinolone resistance.The results of the current study highlight food-producing animals as a potential reservoir of antimicrobial-resistant bacteria and clinically important resistance genes.More attention should be paid to the surveillance of such strains.

Objective To characterize the roles of different quinolone resistance mechanisms in quinolone-resistant Escherichia coli isolates,including different topoisomerase point mutations,efflux pumps and outer membrane proteins.Methotis Through homologous gene recombination methods,different quinolone-resistant mechanisms of E. coli mutants were constructed and the susceptibility changes of these mutants to different antimicrobials were measured.Resuits Efflux pumps AcrAB and outer membrane protein TolC played different roles in different E. coli isolates.Compared with other mechanisms,the mutations in topoisomerases played a dominant role in quinolone resistance.Only the mutations jn parC had no effect on quinolone resistance,which further confirmed parC was the secondary target of quinolones in E.coli.Fluoroquinolone susceptible E.coli would automatically become highly resistant to quinolones after acquiring the point mutations in both gyrA(S83L,D87N)and parC(S80I,A108V),but not requiring the over-expres-sion of efflux.Conclusion The mutations in topoisomerases play a dominant role in E.coli quinolone resistance,and the mutations in both gyrA and parC are required.

Objective To characterized the Salmonella enterica serotype typhimurium isolates recovered during 2002 to 2005 from outpatients in Tongji Hospital, Wuhan China. Methods The 36 isolates from Tongji Hospital were characterized by antimicrobial-susceptibility testing and screened for class Ⅰ integrons, beta-lactamase genes, qnr, aac(6')-Ib-cr and mutations in the quinolone resistance determining regions (QRDRs) by PCR and DNA sequence analysis. All isolates were also characterized by pulsed-fieldgel electrophoresis (PFGE) to determine the genetic relateness among these isolates. Results All isolates displayed multidrug resistance and most of them harbored class Ⅰ integrons. Ciprofloxacin-resistant isolates showed significant difference compared with ciprofloxacin-susceptible isolates after PFGE analysis. All 31 ciprofloxacin resistant isolates carried at least three mutations in the QRDR of GyrA and ParC. Three ciprofloxacin resistant isolates had accumulated additional mutation in ParE. Five isolates harboring the OXA-30. Enzyme showed intermediate resistant to eefepime. Conclusions Fluoroquinolone-resistant Salmonella typhimurium isolates were widely distributed among the outpatients in Wuhan and the resistant isolates accumulated multiple antimicrobial resistant mechanisms and showed unique genetic profiles. The state and local health authority must remain vigilant for the emergence of Salmonella typhimurium resistant to both third generation cephalosporins and fluoroquinolonos.