intravenous bolus

in·tra·ve·nous bo·lus

a relatively large volume of fluid or dose of a drug or test substance given intravenously and rapidly to hasten or magnify a response; in radiology, rapid injection of a large dose of contrast medium to increase opacification of blood vessels.

in·tra·ve·nous bo·lus

(in'tră-vē'nŭs bō'lŭs) 1. A relatively large volume of fluid or dose of a drug or test substance given intravenously and rapidly to hasten or magnify a response. 2. radiology Rapid injection of a large dose of contrast medium to increase opacification of blood vessels.