Double-contrast barium enema bowel. Double-contrast barium enema A double-contrast barium enema is a form of contrast radiography in which x-rays of the colon and rectum are taken using two forms of contrast to make the structures easier to see. A liquid containing barium (that is, a radiocontrast agent) is put into the rectum. Barium is a silver-white metallic compound that outlines the colon and rectum on an x-ray and helps show abnormalities. Air is also put into the rectum and colon to further enhance the x-ray. Double-contrast barium enemas are less invasive than a colonoscopy and have comparatively fewer issues in a viable
Colon (punctuation) of a list: while a double colon codice_3 is read as "has type of" (compare scope resolution operator): The ML languages (including Standard ML and OCaml) have the above reversed, where the double colon (codice_3) is used to add an element to the front of a list; and the single colon (codice_5) is used for type guards. MATLAB uses the colon as a binary operator that generates vectors, as well as to select particular portions of existing matrices. In Python, which uses indentation to indicate blocks, the colon is used in statements to indicate that the next line is the