Comparative Investigation of Intravenously Administered Omnipaque and Isovue: Effects on Serum Creatinine Concentration in Outpatients

For patients without known kidney disease, it is exceptionally rare for the administration
of CT contrast agents to injure the kidneys, and those rare injuries that do occur are
almost always temporary (a week or two) and heal. Indeed, significant injuries are so rare
that the kidney function in patients is not routinely checked after they receive CT contrast
agents. There are many brands of contrast media in common use across the United States, and
it has been thought in the past that all are similarly low in risk. The purpose of this
study is to examine whether two different contrast materials might differ in their risk to
the kidneys. We will perform a direct comparison of Omnipaque-300 (iohexol, 300 mg I/ml)
and Isovue-300 (Iopamidol, 300 mg I/ml) low osmolality contrast agents to determine their
relative CIN rates (as measured by serum creatinine concentration) in low-risk patients.

Inclusion Criteria:

- Patients 18 years of age and older

- Patients referred for a contrast-enhanced CT examination. Such contrast- enhanced CT
examinations include, but are not limited to, certain examinations of the head, neck,
chest, abdomen, pelvis, etc.

Exclusion Criteria:

- Patients less than age of 18 years of age

- Pregnant patients

- Patients unable to provide written informed consent

- Patients in whom there are contraindications to the administration of intravenous
contrast material (as detailed in out Department of Radiology intravenous contrast
material use guidelines), including renal contraindications (such as a University of
Michigan laboratory record of most recent serum creatinine concentration of >1.5
mg/dl or an estimated glomerular filtration rate (EGFR) <60 ml/min); if no serum
creatinine is available, patients will be receive contrast material based on
departmental guidelines

- Patients who are undergoing therapy with agents purported to reduce the risk of CIN
(such as acetylcysteine, theophylline, or intravenous hydration)

- Patients who are unable to provide the follow-up serum creatinine concentration
measurements

- Patients undergoing CT examinations that utilize a higher concentration of iodine
(for example, 370 mg I/ml contrast material)

- Patients who have experienced allergic-like reactions to contrast; including patients
who receive corticosteroid/antihistamine premedication to reduce the risk of an acute
allergic-like reaction

- Patients who do not receive the study criterion for dose of contrast material; and
patients in whom a contrast extravasation of more than 5 ml occurs (so that it is not
possible to determine how much contrast material the patient received as a direct
intravenous injection)

- Patients participating in other investigational drug, contrast material, or device
trials