Contrast Studies & Labs
Certain imaging studies require contrast media in order to identify structures within an organ or system. This technique allows visualization of soft tissue structures and evaluation of size, shape and position.
CT and X-rays that require contrast typically use iodine or barium compounds. Depending on the study, they can be performed with contrast as well as without and with contrast.
Magnetic resonance imaging (MRI) functions through different principles and utilizes different contrast agents. These compounds are typically gadolinium-based and work by altering the magnetic properties of nearby hydrogen nuclei. Importantly, MRI studies need to be performed without and with contrast so that the radiologist can differentiate between different tissues and even different types of disease.
Depending on the contrast agent used, certain labs (e.g., creatinine or BUN) must be drawn to minimize the chance of a patient having an adverse reaction to an MRI, CT, X-ray or other study performed with contrast.
Referring providers who know exactly which approach to contrast is needed for a particular exam are encouraged to indicate this on the order request.
However, when there is uncertainty, Wake Radiology strongly recommends that referring practices select the box indicating “contrast as determined by radiologist” when ordering any type of CT or MRI study. This approach:
- Allows Wake Radiology to perform the correct study the first time around
- Eliminates unnecessary duplicate exams
- Reduces the number of phone calls need during the scheduling process as well as additional paperwork needed to cancel and recreate an order with the final exam code
Providers who would like to discuss the Wake Radiology contrast recommendation for any given patient are invited to contact our radiologists by calling our physician hotlines.
Creatinine labs for contrast studies
Wake Radiology offices have an iSTAT device onsite so we can obtain a patient’s creatinine level if they need a contrast-enhanced procedure.
If your office doesn’t have labs on file (or if they are outdated), simply write “Creatinine Labs” on the order or check the “draw for Creatinine level if medically indicated” box on our Main Order Form under CT and MRI exams. Wake Radiology will do the rest.
Labs for creatinine levels are drawn on the same day as the exam for your patient’s convenience. This also ensures that their imaging procedure is performed safely and efficiently.
The importance of creatinine levels
Some imaging studies require IV contrast to help certain areas of the body better present during an image. The most commonly used contrast materials can cause problems for patients with renal disease.
Creatinine is a chemical waste product that’s produced by muscle metabolism and, to a smaller extent, by eating meat. Healthy kidneys filter creatinine and other waste products from a patient’s blood. If a patient’s kidneys aren’t functioning properly, an increased level of creatinine may accumulate in their blood. A serum creatinine test measures the level of creatinine in the blood and provides an estimate of how well the kidneys are filtering (estimated glomerular filtration rate or eGFR). This test helps determine who is at higher risk so precautions can be taken.
The following patients must have eGFR in the time frame specified in the table below.