Omnipaque Versus Gastroview as Oral Contrast for Abdominal and Pelvic CT

Participants must be scheduled for a CT scan prior to enrollment in this study. Informed consent will be obtained from patients acceptable to be included in the study. It will be noted if there is a history of gastrointestinal surgery and if the patient is nauseated before the contrast is administered.

Patients will be randomized to receive either a standardized dilution of Gastroview or Omnipaque orally. The two agents will be prepared to have nearly equivalent iodine concentration. No flavoring agent (ie Crystal Light) will be added. The plan is to mix the agents per manufacturer recommendation as follows:

Omnipaque 350 26cc in 974 cc of water (9.0g iodine) Gastroview 25cc in 1000cc of water (9.17g iodine)

The time the patients start and stop consuming the contrast as well as the volume taken and time from first drink to start of the scan will be recorded by a blinded investigator. Patients will be asked to drink 900cc. Technical staff will report any side effects or complications observed.

After completion of the CT scan, patients will fill in a survey rating the taste of the agent on a 5 point scale, and will be asked to report any side effects. Planned rating scale is as follows:

• 2=Dislike very much
• 1=Dislike moderately 0=Neither like nor dislike

• 1=Like moderately
• 2=Like very much

A taste test between the two agents will then be administered by a blinded investigator. Patients will be given 30 cc of each agent. The order in which the agents are administered will be randomized. Patients will be asked to rate preference, if any, for either agent on a 3 point scale. Potential bias related to which agent was administered for the CT will analyzed from the data.

Planned rating scale is as follows:

• 1- A is better 0 -no difference

• 1- B is better

Patients will be contacted by telephone the day after the CT to assess for any delayed side effects such as diarrhea, constipation, and abdominal cramping experienced in the 24 hours following.

Bowel opacification will be rated by 2 body imagers blinded to the agent the patient received. Degree of opacification of the stomach, duodenum, jejunum, and ileum will be rated on a 4 point scale. If contrast has reached the colon, ascending, transverse, descending and sigmoid will be similarly evaluated. Four point rating scale is as follows:

0= absent opacification

• minimal (<25% of analyzed segments opacified)
• good (>25 % and < 75% of analyzed segments opacified)
• excellent (> 75% of analyzed segments opacified)

Description of tests/procedures to be performed. Patients will undergo contrast enhanced abdominal pelvis CT as ordered by the referring clinician. Patients will be randomized to either dilute Omnipaque or dilute Gastroview for oral contrast. Both agents will be in a concentration of 9 mg of iodine/ml, and a volume of 900 cc.

Inclusion criteria

• Patients at least 19 years of age scheduled for outpatient contrast enhanced abdominal pelvic CT at The Kirklin Clinic in Birmingham Alabama as part of clinical care with the patient's provider will be screened for eligibility.

Exclusion criteria

• Not competent to give consent.
• Pregnant.
• Known allergy to either of the contrast agents.
• Loss of sense of taste or smell.
• Contraindication to oral administration such as aspiration risk.