Objective To evaluate the value of the periportal free air(PPFA) sign at computed tomography(CT) in distinguishing between upper and lower gastrointestinal(GI) tract perforation. Methods CT images of 62 patients with surgically proven GI tract perforation were retrospectively analyzed. 62 cases included upper and lower GI tract perforation in 35 cases and 27 cases,respective-ly. When there was free air in the periportal area,it was defined as positive periportal free air(PPFA) sign. The difference of PPFA sign in upper and lower GI tract perforation, and the sensitivity, specificity, positive predictive value, negative predictive value and ac-curacy of PPFA sign in diagnosing gastrointestinal perforation were analysed respectively. Results The PPFA sign was seen in 33 of 35(94%) patients with upper GI tract perforation,but only in 10 of 27 (37%) patients with lower GI tract perforation,there was sig-nificant difference between them(P<0.05). For diagnosis of super GI perforation with PPFA sign, the sensitivity, specificity, positive predictive value,negative predictive value and accuracy were 94% (33/35), 63%(17/27), 770%(33/43), 89%(17/19) and 81% (50/ 62), respectively. Conclusion The PPFA sign is a useful finding in distinguishing between upper and lower GI tract perforation.

Clinics in the Olympic venues make a critical component in the medical service system for Olympic venues. The clinic in the fencing hall is cited as an example in this paper, which introduced the experiences and lessons learnt from the site preparation, personnel deployment and management, rules and regulations, and drug/instrumentation readiness.

Objective:To assess the value of amide proton transfer weighted (APTw) imaging in the evaluation of pH changes in infarct core (IC) and ischemic penumbra (IP) in subacute cerebral infarction.Methods:The data of twenty-three subacute cerebral infarction patients with unilateral steno-occlusive disease of the middle cerebral artery (subacute infarction group) from April to November 2019 in the First Affiliated Hospital of Dalian Medical University were prospectively analyzed. Fifteen healthy volunteers were enrolled in this study as the control group. All subjects underwent conventional MRI, DWI, 3D-pseudo continuous arterial spin labeling (3D-pCASL) and APTw sequences. Based on DWI images, relative cerebral blood flow (rCBF) and APTw images to determine the region of IC, blood flow penumbra [cerebral blood flow(CBF)-DWI mismatch area, IP CBF] and metabolic penumbra (APTw-DWI mismatched area, IP APT). 3D ROIs were used to semi-automatically measure the APTw signals and the volume of IC and IP CBF of the patients in subacute infarction group. The comparison of APTw signals between the infarct side and the contralateral side in the subacute infarction group, the comparison of bilateral APTw signals in the control group, and the comparison of APTw signals in the IC and IP CBF regions were performed by paired-sample t test or Wilcoxon signed-rank test. The paired-sample t test or Mann-Whitney U test was used to compare the APTw signals between the two groups. The Friedman test was applied to compare the difference of volumes among IP CBF1.5, IP CBF2.5 and IP APT . Results:There was no significant difference of the APTw signals among the IC, the contralateral side in the subacute infarction group and the control group ( P>0.05). The APTw signals of IP CBF and IC of the infarction group were statistically different ( P<0.05). Compared with the contralateral side of IP CBF1.5 (3.7±1.7, -1.84±1.48, 5.57±2.75), the APTwmax (3.07±1.41, t=-3.012, P=0.006), APTw min [-1.30 (-1.74, -0.57), Z=-2.099, P=0.036], and APTwmax-min(4.51±2.58, t=-3.273, P=0.003) signals in the IP CBF1.5 were decreased ( P<0.05). Compared with the contralateral side of IP CBF2.5 [-1.53 (-2.80, -0.91), 5.31±2.61], the APTw min [-1.08 (-1.60, -0.49), Z=-2.616, P=0.009] and APTwmax-min (4.41±2.72, t=-3.228, P=0.004) signals in the IP CBF2.5 were decreased. The volumes of IP CBF1.5 [107.51(50.08, 138.61)mm 3], IP APT [99.00 (53.27, 121.335) mm 3] and IP CBF2.5 [89.91 (51.53, 139.87) mm 3] were successively reduced (χ2=7.913, P=0.019), and the volume of IP CBF2.5 was significantly smaller than that of IP CBF1.5 ( P=0.037). Conclusion:The acid-base metabolism in the IC of subacute cerebral infarction is not obvious, but the blood flow penumbra has local acid-base metabolism imbalance, and the range of metabolic penumbra coincides with the blood flow penumbra.

Objective: To investigate the prevalence of flat feet and associated factors in school aged children in Kunming City, to provide evidence supporting the prevention of flat feet. Methods: From December 2021 to February 2022, 4 444 children aged 7-13 in five primary schools in Kunming were screened for flat feet with the optical foot assessment and recording device. The incidence of flatfoot was counted, and Logistic regression was used to analyze the influencing factors of flatoccurrence. Results: The overall prevalence rate was 29.10%, of which 21.79% were mild, 52.43% were moderate, 25.78% were severe, 89.10 % were bipedal, and 10.90% were monopedal. The prevalence rates in the 7-year old and 13-year old groups were 36.91% and 10.43%, respectively, and the risk in the former was 5.00 times that in the latter( OR=5.00, 95%CI =3.22-7.52). The prevalence rates in rural and urban students were 38.53%, 22.46%, respectively, and the risk in the former was 2.17 times that in the latter( OR=2.17, 95%CI =1.90-2.47). The prevalence of flat feet in male and female students were 34.21%, 23.29%, respectively, and the risk in male students was 1.71 times higher than that in female students( OR=1.71, 95%CI =1.50-1.95). The incidence of flat feet correlated with BMI, and the risk of flat feet was higher in the group with overweight and obese groups than normal( OR=1.31, 1.10, P < 0.01). Conclusion The prevalence of flat feet in school age children aged 7-13 years decreased with age. The prevalence and risk of flat feet is lower in girls than boys, and the incidence and risk of flat feet are lower in urban than rural children. The incidence of flat feet in most children is moderate, and the risk increased with increasing BMI. For school aged children with flat feet, early prevention, detection and treatment are needed.

Objective:To explore the consistency of MRI fast field echo resembling a CT using restricted echo-spacing (FRACTURE) and CT in the evaluation of knee and ankle bone changes.Methods:From November 2020 to November 2021, seventeen patients who underwent CT and MRI FRACTURE examinations of knee joint or ankle joint in the First Affiliated Hospital of Dalian Medical University were retrospectively collected, including 14 patients with knee joint examinations and 3 patients with ankle joint examinations. According to the number of joint components, 80 components were included, including 14 for femur and patella, 17 for tibia and fibula, and 3 for talus, scaphoid, medial cuneiform, medial cuneiform, lateral cuneiform and calcaneus, respectively. The fracture, hyperosteogeny, and bone destruction of the joint bones were evaluated by two observers using CT and FRACTURE images, respectively. Kappa test was used to analyze the consistency of CT and FRACTURE images between observers in the evaluation of joint bone lesions.Results:The Kappa values (95%CI) of the consistency evaluation of fracture, hyperosteogeny, and bone destruction by CT and FRACTURE images were 0.925 (0.823-1.027), 0.905 (0.799-1.011) and 0.895(0.752-1.038) respectively for observer 1, and were 0.963 (0.892-1.034), 0.933 (0.843-1.023) and 0.886 (0.731-1.041) respectively for observer 2. The Kappa values (95%CI) of the consistency evaluation of fracture, hyperosteogeny, and bone destruction by observers 1 and 2 via CT images were 1.000 (1.000-1.000), 0.937(0.851-1.023) and 0.945 (0.839-1.051) respectively, and that by FRACTURE images were 0.962 (0.888-1.036), 0.966 (0.899-1.033) and 0.836 (0.656-1.016) respectively.Conclusion:For the evaluation of fracture, hyperosteogeny, and bone destruction of knee joint and ankle joint, MRI FRACTURE sequence is highly consistent with CT.

Objective:To establish a multilocus sequence typing (MLST) assay for Corynebacterium ( C.) striatum, explore the population structure and evolution relationship of clinical isolates of C. striatum. Methods:Seven housekeeping genes ( gyrA, gyrB, hsp65, sodA, secA1, rpoB, 16S rRNA) were amplified with PCR by using self-designed specific primers and sequenced. Then, the sequences were assembled with software SeqMan. The gene diversity and gene recombination characteristics were evaluated by using software DnaSP 5.10.01 and Splits tree 4.14.2. The phylogenetic tree and the minimum spanning tree were constructed based on the sequence types (ST) characteristics by using software MEGA 7.0.14 and BioNumerics, respectively. In addition, the genetic evolutionary relationship among STs were analyzed by using software eBURST 3.0. Results:The expected amplification products of seven sites selected in all the test strains were obtained. Splits tree showed that the clustering of all C. striatum strains was consistent, suggesting that gene recombination is the potential driving force for the evolution of C. striatum. All of the 344 C.striatum strains were divided into 72 STs by MLST and 85.7% of the strains formed clonal complexes. CC19 was the predominant clonal complex, whereas ST16 in the clonal complex was detected in the most strains. ST had a certain geographic clustering and a certain correlation with the isolation time. Conclusions:C. striatum showed high genetic diversity in China and CC19 was the predominant clonal complex. The MLST assay established in this study can be used for the typing of C. striatum, but further improvement is needed.

Purpose/Significance To deeply analyze the research progress on the application of medical knowledge graph in the field of stroke,to discuss the problems of the development of stroke knowledge graph in China,and to put forward suggestions for the construc-tion of stroke knowledge graph.Method/Process By reviewing and analyzing the relevant literature,the application of medical knowledge graph in the field of stroke is sorted out and summarized.Result/Conclusion There are still many deficiencies in the development of stroke knowledge graph in China,and in the future,in-depth research can be carried out from four aspects,namely,expanding the ap-plication scope of knowledge graph,promoting the fusion of knowledge graph,developing more efficient algorithms,and upgrading to cog-nitive graph by joint artificial intelligence(AI).

Objective:To investigate the computed tomography (CT) features of adenocarcinoma of esophagogastric junction (AEG) after neoadjuvant chemotherapy.Methods:The retrospective and descriptive study was conducted. The clinicopathological data of 59 patients with AEG who underwent neoadjuvant chemotherapy in Peking University Cancer Hospital from February 2010 to November 2014 were collected. There were 51 males and 8 females, aged from 46 to 82 years, with a median age of 63 years. All the 59 patients underwent enhanced CT examination before and after neoadjuvant chemotherapy. Observation indicators: (1) pathological examination and neoadjuvant chemotherapy of patients with AEG; (2) results of CT examination in patients with AEG, including ① qualitative indicators of CT and ② quantitative indicators of CT. Measurement data with skewed distribution were represented as M( P25, P75) or M (range), and comparison between groups was analyzed using the Mann-Whitney U test. Count data were described as absolute numbers, and comparison between groups was analyzed by the chi-square test. Results:(1) Pathological examination and neoadjuvant chemotherapy of patients with AEG: of the 59 patients with AEG, high-differentiated adenocarcinoma was observed in 1 patient, moderate-differentiated adenocarcinoma in 40 patients, and low-differentiated adenocarcinoma in 18 patients. Effective response to neoadjuvant chemotherapy was observed in 13 patients, including 6 patients of pathological tumor regression grading (pTRG) 0 and 7 of pTRG 1; poor response was observed in 46 patients, including 12 patients of pTRG 2 and 34 patients of pTRG 3. (2) Results of CT examination in patients with AEG. ① Qualitative indicators of CT: for the 13 patients with effective response to neoadjuvant chemotherapy, 13 had the presence of ulcers, 5 had layered enhancement, 10 had infiltration of adventitia surface, and 2 had positive extramural venous invasion (EMVI) before neoadjuvant chemotherapy; after neoadjuvant chemotherapy, 13 had shallowed or disappeared ulcers, 7 patients had changed enhancement pattern, 3 had infiltration of adventitia surface, and 1 had positive EMVI. For the 46 patients with poor response to neoadjuvant chemotherapy, 28 had the presence of ulcers, 18 had layered enhancement, 37 had infiltration of adventitia surface, and 22 had positive EMVI before neoadjuvant chemotherapy; after neoadjuvant chemotherapy, 23 had shallowed or disappeared ulcers, 7 patients had changed layered enhancement pattern, 33 had infiltration of adventitia surface and 21 had positive EMVI, respectively. There was no significant difference in the layered enhancement or infiltration of adventitia surface before neoadjuvant chemotherapy between patients with different treatment response ( χ2=0.002, 0.000, P>0.05). There were significant differences in the presence of ulcers and positive EMVI before neoadjuvant chemotherapy between patients with different treatment response ( χ2=5.591, 4.421, P<0.05). After neoadjuvant chemotherapy, there were significant differences in the changes of layered enhancement pattern, infiltration of adventitia surface and positive EMVI between patients with different treatment response ( χ2=6.359, 10.090, 4.728, P<0.05); while there was no significant difference in the shallowed or disappeared ulcers between patients with different treatment response ( χ2=1.239, P>0.05). ② Quantitative indicators of CT: for the 13 patients with good response to neoadjuvant chemotherapy, the maximum tumor height, the maximum tumor area, enhanced CT value of the lesion before neoadjuvant chemotherapy were 1.37 cm(0.94 cm, 1.88 cm), 8.9 cm 2 (4.7 cm 2, 9.9 cm 2), 53 HU(47 HU, 63 HU), respectively. After neoadjuvant chemotherapy, the above indicators were 1.17 cm(0.79 cm, 1.29 cm), 4.4 cm 2(2.5 cm 2, 6.1 cm 2), 30 HU(25 HU, 53 HU), respectively. The change rates of the maximum tumor height, the maximum tumor area, and enhanced CT value of the lesion were -23%(-42%, 9%), -51%(-60 %, -21%), -44%(-51%, 19%), respectively. For the 46 patients with poor response to neoadjuvant chemotherapy, the maximum tumor height, the maximum tumor area, enhanced CT value of the lesion were 1.57 cm(1.21 cm, 1.96 cm), 9.4 cm 2(6.6 cm 2, 13.1 cm 2), 60 HU(53 HU, 66 HU) before neoadjuvant chemotherapy, respectively. After neoadjuvant chemotherapy, the above indicators were 1.16 cm(0.94 cm, 1.37 cm), 6.2 cm 2(4.8 cm 2, 8.1 cm 2), 55 HU(47 HU, 65 HU), respectively. The change rates of the maximum tumor height, the maximum tumor area, and enhanced CT value of the lesion were -27%(-38%, -9%), -33%(-47%, -12%), -9%(-22%, 9%), respectively. There was no significant difference in the maximum tumor height, the maximum tumor area, enhanced CT value of the lesion before neoadjuvant chemotherapy between patients with different treatment response ( Z=-1.372, -1.372, -1.331, P>0.05). There was no significant difference in the maximum tumor height after neoadjuvant chemotherapy between patients with different treatment response ( Z=-0.503, P>0.05), while there were significant differences in the maximum tumor area and CT value of the lesion ( Z=-2.743, -3.049, P<0.05). There was no significant difference in the change rate of the maximum tumor height or the maximum tumor area between patients with different treatment response ( Z=0.000, -1.481, P>0.05), while there was a significant difference in the change rate of CT value of the lesion ( Z=-3.231, P<0.05). Conclusion:Effective response of AEG to neoadjuvant chemotherapy was characterized by the changes in tumor layered enhancement pattern, reduction in the maximum tumor area, reduced CT value of the lesion, negative infiltration of adventitia surface, and negative EMVI.

Objective:To investigate the change of syndesmotic volume via CT scan in Danis-Weber B type ankle fracture, aiming to provide a non-invasive diagnostic method for Danis-Weber B type ankle fracture combined with syndesmotic injury.Methods:Retrospective analysis was performed on 48 patients with Danis-Weber B type ankle fractures in Shanghai Sixth People′s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine from January 2018 to March 2022, including 30 males and 18 females, aging (43.71±19.41) years. Ankle CT scans and three-dimensional reconstructions were performed before surgery and at the last follow-up, measuring the syndesmotic volume between the tibiotalar joint and 1, 3 and 5 cm above the ankle and compared with each other. Intraoperative exploration was used as the gold standard for the syndesmotic injury. Based on the results of exploration of the syndesmotic injury, patients were divided into simple ankle fracture group (fracture group, 25 cases) and ankle fracture combined with syndesmotic injury group (fracture + ligament group, 23 cases). The sensitivity and specificity of this diagnostic method were statistically evaluated. The assessments at the last follow-up were performed to value the clinical effect of surgery. The metric data conforming to the normal distribution were expressed as mean ± standard deviation ( ± s), and the t-tests were used for comparison between groups. The measurement data of skewed distribution were expressed as quartile M( Q1, Q3), and nonparametric tests were used for intergroup comparison. Counting data were expressed as number of cases and percentage (%), and Chi-square test were used for intergroup comparison. Results:In the fracture group, there were no statistically significant differences of the syndesmotic volume at 1, 3, and 5 cm above the ankle joint before surgery and at the last follow-up ( P=0.219, 0.269, 0.103). On the contrary, the volume above were statistically significant in the fracture + ligament group ( P<0.001). There were statistically significant differences in syndesmotic volume between the two groups at 1, 3, and 5 cm above the ankle joint preoperatively ( P=0.005, 0.004, 0.038). By contrast, there were no statistical differences between the two groups postoperatively ( P=0.082, 0.155, 0.249). For the sensitivity and specificity of Danis-Weber B type ankle fractures combined with syndesmotic injury, they were 92% and 67% at 1 cm above the ankle joint, 69% and 87% at 3 cm above the ankle joint, and 62% and 87% at 5 cm above the ankle joint, respectively. The last follow-up clinical function score indicated a good surgical outcome. Conclusions:Volumetric measurement via CT scan is one of the diagnostic methods for evaluating Danis-Weber B type ankle fracture combined with syndesmotic injurys. Open resection internal fixation combined with elastic fixation of the ankle fracture combined with syndesmotic injurys can significantly reduce the lower tibiofibular volume, and the efficacy is definite.

Objective:To investigate the efficacy of CT imaging features in evaluating occult peritoneal metastasis (OPM) of diffuse infiltrating gastric cancer (Borrmann Type Ⅳ).Methods:Totally 101 patients with locally advanced Borrmann type Ⅳ gastric cancer were retrospectively collected who were admitted to Peking University Cancer Hospital from March 2014 to March 2021. The patients were divided into OPM group (53 cases) and the non-OPM group (48 cases) according to the results of preoperative CT and laparoscopic exploration/peritoneal cytology examination. The pathological examination results were recorded, including the degree of histological differentiation and Lauren classification. The evaluation indicators included the tumor center position, the number of tumor-occupied portions, involved orientation, mucosal broadband sign, stratified enhancement, serosa invasion, increased density of peripheral fat tissue, and enlarged lymph nodes. The maximum thickness of the primary tumor, average CT value of the primary tumor (arterial phase, venous phase, and delayed phase), difference between venous phase and arterial phase, difference between delayed phase and venous phase, and pattern of the enhanced curve were recorded. The Mann-Whitney U or Chi-square test was used to compare the differences of pathological and CT features between two groups. The multivariate logistic regression was used to screen independent predictors and establish a nomogram. The receiver operating characteristic curve was used to evaluate the performance of the nomogram in predicting OPM, and the Hosmer-Lemeshow test was used to test the model′s goodness of fit. Results:There was statistical significance in the seven indicators between the OPM and non-OPM groups, including tumor-occupied portions of stomach, mucosal broadband sign, stratified enhancement, serosa invasion, increased density of peripheral fat tissue, the enhanced curve pattern and the degree of histological differentiation ( P<0.05). Among them, the degree of histological differentiation (OR=0.19, P=0.033), stratified enhancement (OR=7.02, P=0.005) and serosa invasion (OR=14.27, P<0.001) were independent predictors of OPM. The nomogram was established based on the three significant features. The area under the curve for predicting OPM was 0.826 (95%CI 0.745-0.908), the sensitivity was 0.566 and the specificity was 0.938. The Hosmer-Lemeshow test showed a good agreement between the OPM risk predicted by the nomogram and the actual risk ( P=0.525). Conclusions:The CT features of Borrmann type Ⅳgastric cancer complicated with OPM have specific characteristics. The diagnosis model based on the degree of histological differentiation, stratified enhancement, and serosa invasion had high efficacy in evaluating OPM.