CT Scan of Abdomen and Pelvis (with contrast)

What it is

Without dye, the liver, the bowel wall, a lymph node and a pocket of pus all sit at roughly the same shade of grey on a CT image. Injecting an iodine-based contrast agent changes that: tissues with a rich blood supply take it up and brighten, tissues that are dead or walled off do not, and the difference is what makes a diagnosis visible. This code covers a single imaging pass over the abdomen and pelvis, timed to catch the dye at the moment it has reached the organs. Some protocols also have the patient drink a contrast liquid an hour or two earlier so the bowel is outlined from the inside as well.

Why it is done

• To work up abdominal pain when the suspicion is appendicitis, diverticulitis, a bowel obstruction or a perforation
• To find the source of an unexplained fever, where a collection of pus can hide deep in the abdomen with nothing to feel from the outside
• To look for cancer, to see how far a known cancer has spread, and to measure whether tumors are shrinking on treatment
• To map anatomy before an operation, or to plan the route for a needle biopsy or a drain

What to expect

An IV goes into a hand or arm vein. Many centers ask for a few hours of fasting first, and some hand the patient a contrast drink to finish before the scan. When the injection runs, most people feel a wave of warmth moving through the body, taste metal, and feel as though they have wet themselves — all of it passes in under a minute and none of it means anything is wrong. The scan takes a few minutes. Patients on metformin, with kidney trouble, or with a past reaction to iodine contrast are asked about it beforehand, because it changes how the dose is handled.

Questions worth asking

• Is the contrast agent itself billed as a separate supply line, on top of the scan?
• If I drank oral contrast that then went unused because the plan changed, am I still charged for it?
• I was scanned in the emergency department. Is there a facility fee here that an outpatient imaging center would not have charged?
• If the radiologist recommends a follow-up scan in three or six months, will that repeat be covered at the same benefit level, or treated as a new diagnostic study against my deductible?