Use of Electrical Impedence to Measure Lean Body Weight as a Determinant of the Dose of Contrast Media for Abdominal CT

Use of Electrical Impedence to Measure Lean Body Weight as a Determinant of the Dose of Contrast Media for Abdominal CT

There are several different methods that can be used to determine the dose of iodinated contrast material for a CT scan. These include a standard fixed dose, a dose based on total body weight, a dose based on body mass index, a dose based on lean body weight, and a dose based on estimated lean body weight. The fixed dose method uses a predetermined amount of contrast material for all patients having a CT scan of the abdomen regardless of size. This is the standard procedure currently used at Duke. The other methods use the patient's weight, either the total body weight or lean body weight, to determine the amount of contrast necessary for the CT exam. For this study, the investigators will use the fixed dose, total body weight, the lean body weight, and estimated lean body weight methods. The purpose of this study is to evaluate these five methods of determining the IV contrast volume and which may be best for abdominal CT scanning.

Inclusion Criteria:

• male or non-lactating, non-pregnant females
• 18 years or older who are able to give written informed consent

Exclusion Criteria:

• a chronic underlying liver disease such as cirrhosis, fatty infiltration of the liver or glycogen storage diseases
• patients with a prolonged cardiac transit time such as those with a congested heart failure, a history of prior cardiac valve replacement, or restrictive/constrictive pericarditis
• patients having undergone any other radiological procedure utilizing iodinated contrast with the 24 hours prior to the CT exam
• patients above a certain total body weight (440 lbs.) due to limitation of the scales themselves (determined by manufacturer)
• any subjects with a history of hypersensitivity to iodine-containing compounds or renal insufficiency (serum creatinine >1.8)
• subjects with implanted electronic devices (pacemakers, defibrillators, insulin pumps, etc.)