Your doctor may have special instructions for you in preparation for your test. He or she might prescribe a special diet or use of a laxative, depending on the type of test. If you have not received such instructions or if you do not understand them, check with your doctor in advance.
For some tests your doctor may tell you not to eat for several hours before having the test. This is to prevent any food from coming back up and entering your lungs during the test. You may be allowed to drink small amounts of clear liquids; however, check first with your doctor.
If you are on hemodialysis and treated with a gadolinium-based contrast agent (GBCA), your doctor may perform hemodialysis immediately after you receive the contrast agent .