In a CT scan, abnormalities may be seen in 87% of patients and it should be made with both oral and intravenous contrast. Among imaging studies, MRI has the best tissue contrast, which aids in the identification of masses within the GI tract (intramural masses). Intravenous contrast material is needed to evaluate lesion vascularity. Preferred imaging modalities in the evaluation of GISTs are CT and MRI,: 20–21  and, in selected situations, endoscopic ultrasound. CT advantages include its ability to demonstrate evidence of nearby organ invasion, ascites, and metastases. The ability of an MRI to produce images in multiple planes is helpful in determining the bowel as the organ of origin (which is difficult when the tumor is very large), facilitating diagnosis. Small GISTs
Since GISTs arise from the bowel layer called muscularis propria (which is deeper to the mucosa and submucosa from a luminal perspective), small GIST imaging usually suggest a submucosal process or a mass within the bowel wall. In barium swallow studies, these GISTs most commonly present with smooth borders forming right or obtuse angles with the nearby bowel wall, as seen with any other intramural mass. The mucosal surface is usually intact except for areas of ulceration, which are generally present in 50% of GISTs. Ulcerations fill with barium causing a bulls eye or target lesion appearance. In contrast-enhanced CT, small GISTs are seen as smooth, sharply defined intramural masses with homogeneous attenuation.
It is on the World Health Organizations List of Essential Medicines.Inspired by the response to the 1997 outbreak in Nigeria, the WHO, Médecins Sans Frontières, and other groups created the International Coordinating Group on Vaccine Provision for Epidemic Meningitis Control, which manages global response strategy. ICGs have since been created for other epidemic diseases. Types
Neisseria meningitidis has 13 clinically significant serogroups, classified according to the antigenic structure of their polysaccharide capsule. Six serogroups, A, B, C, Y, W-135, and X, are responsible for virtually all cases of the disease in humans. Quadrivalent (Serogroups A, C, W-135, and Y)
There are three vaccines available in the United States to prevent meningococcal disease, all quadrivalent in nature, targeting serogroups A, C, W-135, and Y:

three conjugate vaccines (MCV-4), Menactra, Menveo and MenQuadfi. The pure polysaccharide vaccine Menomune, MPSV4, was discontinued in the United States in 2017.Menveo and MenQuadfi are approved for medical use in the European Union. Menactra and Menveo
The first meningococcal conjugate vaccine (MCV-4), Menactra, was licensed in the U.S. in 2005 by Sanofi Pasteur; Menveo was licensed in 2010 by Novartis. Both MCV-4 vaccines have been approved by the Food and Drug Administration (FDA) for people 2 through 55 years of age. Menactra received FDA approval for use in children as young as 9 months in April 2011 while Menveo received FDA approval for use in children as young as two months in August 2013. The Centers for Disease Control and Prevention (CDC) has not made recommendations for or against its use in children less than two years.