PurposeGas is rarely studied or reported to be used as a contrast agent of stomach MRI examination because it might lead to susceptibility artifacts, the purpose of this study is to evaluate the application value of gas as a contrast agent of stomach MRI examination.Materials and Methods Sixty patients who were supposed to have upper abdominal MRI examination were enrolled, all patients were given intramuscular injection of 654-2, gas from oral ingestion of aerogenic powder was used as contrast agent, MRI examinations were then executed and images quality of MRI were analyzed and classified. Results All 60 patients felt it acceptable for the taste of aerogenic powder, only 5 cases felt uncomfortable during swallowing; no adverse reactions were observed in all the 60 cases. Excellent gas contrast medium filling of the stomach cavity were confirmed with CT scanning in 57 cases (95%). Gas acted as a negative contrast agent in the stomach cavity with good continuity and uniform signal; and the proximal part of the stomach and duodenum was well displayed. There were 21 cases (35.0%) classified as grade 0 about their image quality; 25 cases (41.7%) as grade 1; 6 cases (10.0%) as grade 2; 8 cases (13.3%) as grade 3, with total 52 cases (86.7%) with image quality which could meet the requirement of clinical diagnosis. Cases of grade 0-2 showed coronary T2WI images with vivid stomach contour and clear stomach wall with no artifacts; axial FS-T2WI images with few artifacts, relative clear stomach contour and good display of stomach wall; less artifact could be found in axial TIWI image with good display of stomach wall; axial T2WI images showed more artifacts and gastric wall was displayed not clear enough. Cases classified as grade 3 showed coronal T2WI, FS-T2WI, T1WI and T2WI axial images with significant artifacts, vague outline, distortions or ghosting of the contour of stomach and tumor.Conclusion As contrast agent for gastric MRI examination, gas is safe, homogeneously distributed with stable signal characteristic and is easy for patients to tolerate.

Objective: This study aimed to analyze and summarize the implementation of the primary prevention program for stroke in Shanghai rural community and evaluate its preventive effect. Methods: A cluster sampling method was used to select approximately 50 000 community natural population from a town in Fengxian District of Shanghai. A primary stroke prevention program was established and implemented in the community from 2008 to 2010 and from 2012 to 2015. The prevention program inclueded stroke health education for the whole population, screening of high risk population of stroke, and therapeutic intervention and management plan for individuals aged≥50 years. The intervention measures were followed up every 2 months. From 2008 to 2015, new stroke cases were monitored dynamically and reviewed annually with classification of stroke diagnosis. The effect of community primary prevention of stroke program was evaluated by the dynamic changes in stroke incidence. Results: From 2008 to 2015, a total of 422 600 individuals were monitored, including 20 500 men and 217 600 women. In 2008, 7 828 individuals were screened and 2 129 individuals were at high risk of stroke were screened, with a high risk rate of 27.2%. In 2012, 2 877 individuals were screened, and 725 individuals were at high risk of stroke were screened, with a high risk rate of 25.2%. The standardized incidence of stroke in this community was 158.1, 105.4, 86.6, 77.6, 89.3, 77.4, 50.7, and 42.3 per 100 000 respectively. The overall incidence image roughly showed a downward trend except 2012(trend test P<0.01). There was no significant difference in the incidence of stroke between men and women in each year. The incidence of stroke increased significantly with age (trend test P<0.01). The age composition of stroke patients is slightly different between different sexes. The proportion of male patients with stroke aged <70 years was significantly higher than that of female patients with stroke, while the proportion of female patients with stroke age>70 years was significantly higher than that of male patients with stroke (P<0.01). Cerebral hemorrhage, cerebral infarction, and subarachnoid hemorrhage accounted for 20.76%, 75.14%, and 4.10%, respectively. Conclusion Based on lifestyle intervention and treatment and control of risk factors, screening high-risk individuals for therapeutic intervention in community population can significantly reduce the incidence of stroke.