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) address colons (and one optional double colon) separate up to 8 groups of 16 bits in hexadecimal representation. In a URL a colon follows the initial scheme name (such as HTTP and FTP), and separates a port number from the hostname or IP address. In BASIC, it is used as a separator between the statements or instructions in a single line, which is represented in other languages via the semicolon. In Forth, a colon "precedes" definition of a new word. Haskell uses a colon (pronounced as "cons", short for "construct") as an operator to add an element to the front