Results: CT Clinical Practice: Oral Contrast

Timing of oral contrast infusion

1. The doctors I scan for are having a battle between Oral Hypaque and Barium. We have our patients drink 1 hour prior to the exam, using hypaque and kool-aide. In some cases, the entire colon is not opacified. Some of the Rads are fine with this stating the entire colon does not need to be opacified unless looking for extravasation, whereas others state they need the entire colon filled, and want the patients drinking for 2-3 hours, or go back to using barium. What do you suggest, and is there any literature on colon opacification?

Answer: Your comments are correct, and we typically do not worry about contrast in the colon on routine cases, especially with newer higher resolution scanners. This winter there may be new contrast agents on the market, with faster transit times.

2. I'm a CT tech. Can you tell me what is the optimal oral contrast dosing and how much for abd/pelvis CT. I want to make sure the contrast is in the entire colon, and the small intestine when we scan the patients. We use barium and flavored gastrograffin.

Answer: For oral contrast to reach the colon with any regularity, you will need to wait 90 -120 minutes after giving 1000 cc of 3% hypaque or gastrograffin.

3. Our new radiologists wanted some info to see what other hospitals are doing for trauma CT scans and oral waiting times

Answer: When a trauma CT is needed, we "just do it", as NIKE says. It is great to get some oral contrast into the bowel, but especially with a 4/8/10/16 slice MDCT you can get great studies with little if any oral, as long as a good IV bolus is used. However, delaying the cans will often put the patient at risk, so "Just do it."

4. The radiologist I work with has commented on the lack of contrast in the descending colon. This is an issue with inpatients and ER patients. We use only gastrograffin @ 3% for all of these patients . Please advise on total volume and delay times after drinking based on specific diagnosis of AP, diverticulitis, obstruction and non-specific epigastric pain.

Answer: To get contrast in the descending colon, routinely via PO, you will need a 2-3 hour wait or so in most patients. If you really need the left colon distended, we use a dilute 3% hypaque as a rectal enema.