Objective:To access the efficacy of monoenergetic imaging from spectral CT combined with metal artifact reduction for orthopedic implants (O-MAR) on reducing contrast hardening artifacts in the vein on the injection side, and determining the optimal monoenergetic spectral range to improve the display of axillary lymph node.Methods:A total of 35 patients with breast cancer who underwent chest-enhanced CT scans were enrolled in this retrospective study. The original data were reconstructed to obtain a total of 35 sets of images, including one conventional image, 17 groups of monoenergetic images, and 17 groups of monoenergetic+O-MAR images. The areas of interest were delineated in the high and low-density artifact area on the injection side of the same layer contrast agent, and the contralateral ectopectoralis. The CT value and its standard deviation (SD) were recorded respectively, the artifact area was measured, and the number of axillary lymph nodes was recorded. The difference in CT values (ΔCT 1, ΔCT 2) and the artifact index (AI1 and AI 2) of the high and low-density artifact areas relative to the contralateral ectopectoralis in the same layer were calculated respectively. Friedman test and Wilcoxon signed-rank test were used to compare the differences of ΔCT, AI, artifact area, and number of lymph nodes among the three imaging modalities, and the Kappa test was used to compare the differences in subjective evaluation. Results:As the energy level increased, compared to the conventional image, monoenergetic image, ΔCT 1 absolute value, ΔCT 2 absolute value, AI 1, and AI 2 showed a trend of initially low and then high, artifact area decreased, and the number of detected lymph nodes increased ( P<0.01). Compared to other energy levels, when the monoenergetic image was 100 keV, ΔCT 1 value, 140 keV for ΔCT 2 value, 120 keV for AI 1 value, and 130 keV for AI 2 value were close to zero, and the number of detected lymph nodes was highest at 110-200 keV. In contrast, in the monoenergetic+O-MAR images, ΔCT 1 absolute value showed a trend of initially low and then high, but, ΔCT 2 absolute value, AI 1, AI 2, and artifact area all significantly decreased, whereas the number of detected lymph nodes significantly increased (χ 2 values were 916.23, 895.93, 387.08, 519.41, 890.10, and 1027.98, respectively. All P<0.01). Compared to other energy levels, when the monoenergetic+O-MAR image was at 100 keV, ΔCT 1 value was close to zero, while ΔCT 2 value became close to zero with increasing energy level, and the number of detected lymph nodes was highest at 110-200 keV. As the energy level increased, the ΔCT 1, AI 1, AI 2, and artifact area of monoenergetic+O-MAR images were significantly smaller than those of monoenergetic images at the same energy level, and the number of detected lymph nodes was significantly higher than that of monoenergetic images ( P<0.01). The subjective scores for 110-200 keV monoenergetic images and 100-200 keV monoenergetic+O-MAR images were both higher than 4, and the score for monoenergetic+O-MAR images was significantly higher than that of single-energy spectrum images. The agreement between the two radiologists in assessing subjective scores was good. Conclusion:At 100-120 keV level, spectral CT monoenergetic combined with O-MAR imaging technique has the best performance in removing hardening-induced artifacts of chest-enhanced CT contrast agent and detecting and displaying axillary lymph nodes.

Objective:To investigate the infection status of Yersinia in the main host animals of plague in Xiahe and Luqu counties, the Himalayan marmot plague foci of Gansu Province, and to provide a basis for exploring the epidemic status of plague in these foci. Methods:Samples of the ileocecal region and contents, pharyngeal swabs (or tongue roots), and blood of the main host animals of plague in Xiahe County and Luqu County where the plague were active in the 1950s and 1960s were collected from 2014 to 2018. The Yersinia isolation, virulence determination and F1 antibody detection were performed, respectively. Results:Totally 24 strains of Yersinia were detected in 958 samples of ileocecal region and contents with a bacterial detection rate of 2.51%, which were 13 strains of Yersinia enterocolitia (Y.e), 1 strain of Yersinia kristensenii (Y.k), 2 strains of Yersinia frederiksenii/ intermedia (Y.f/i), 6 strains of Yersinia intermedia (Y.i), 1 strain of Yersinia aldouae (Y.a) and 1 strain of Yersinia massiliensis (Y.m). Totally 19 strains of Yersinia were detected in 958 samples of pharyngeal swabs (or tongue roots), and the detection rate was 1.98%, which were 8 strains of Y.e, 1 strain of Yersinia pseudotuberculosis (Y.p), 4 strains of Y.k, 1 strain of Y.f/i, 4 strains of Y.i, and 1 strain of Yersinia ruckeri (Y.r). The virulence types of 21 strains of Y.e were ail -ystA -ystB +yadA -virF -rfbc -, ail -ystA -ystB -yadA -virF -rfbc -, respectively, accounting for 9.52% (2/21) and 90.48% (19/21), none were pathogenic. The results of F1 antibody in 1 079 serum samples were all negative. Conclusions:Yersinia are widely found in the pharynx and intestines of the main host animals of plague in Xiahe and Luqu counties, and the Y.e detected are all non-pathogenic strains. The results of this investigation can provide clues for further study on the preservation of Yersinia pestis in host animals and their living environment.

Objective To type Yersinia pestis isolated from Gansu Province,and to study the trend of diffreent strains in different administrative regions and different years.Methods Totally 193 strains were enrolled in this study,including 9 strains of Ganning Dauricus type,18 strains of Aerjin type,45 strains of Qilian type and 121 strains of Qingzang type.These strains were genotyped by clustered regularly interspaced short palindromic repeats (CRISPR),and genotypes were named according to international standard.Genotyping by CRISPR in different administrative regions and different years of Gansu Province was explored.Results Two clusters (Ca7 and Cb4),including four genotypes (genotypes 7,22,24 and 26) were classified by CRISPR.From the point of view of origin,genotype 24 was the main genotype in Akesai 36.36％ (16/44),Subei 36.17％ (17/47),Yumen 50.00％ (5/10) and Su'nan 38.67％ (29/75);the main genotype of Xiahe and Huining was genotype 26 (4/7);the main genotype of Shandan was genotype 22 (1/1).From the point of view of time,the main genotype of Yersiniapestis in Gansu Province during the years of 1960-1969,1970-1979 and 1980-1989 was genotype 26 [53.33％ (8/15),60.00％ (6/10) and 48.28％ (14/29)];the main genotype was genotype 22 [40.91％ (18/44)] during the years of 1990-1999;and the main genotype was genotype 24 [43.16％ (41/95)] during the years of 2000-2009.Conclusion Four genotypes of Yersiniapestis in Gansu Province are quite different in different administrative regions and different years.

We investigated the common diseases in patients from village clinics and compared them to those of the general population in rural areas of Jiangsu Province.We found that the treatment rates of chronic diseases such as hypertension and diabetes mellitus were quite low.Village clinics should play a more active role in health record management,healthcare education,and management of chronic diseases for the farmers.