Before the test: It is important that the colon and rectum are emptied before this test to
provide the best images. This is why the preparation for this test is similar to that for a
double-contrast barium enema or colonoscopy. You will probably be told to follow a clear
liquid diet for a day or 2 before the test. You will also be given instructions for taking strong
laxatives and/or enemas the night before or morning of the exam. You will probably be in the
bathroom quite a bit.