Contrast materials, also called contrast agents or contrast media, are used to improve the accuracy of medical images produced by x-rays, computed tomography (CT), and magnetic resonance (MR) imaging. Although rare, allergic reactions to IV contrast can occur in a minority of patients. RAF takes a proactive stance on consulting with our referring physicians in order to prepare patients for these studies in advance. Our goal is to make medical imaging tests both comfortable and safe for your patients.
What are the IV contrast agents that you use?
We use two basic types of IV contrast agents, iodinated contrast for x-ray studies (ex: CT, IVP) and gadolinium-based contrast for MRI.
Which patients receiving IV contrast need premedication:
- Patients who have only had vasovagal reactions, nausea, vomiting, or contrast-induced renal dysfunction do NOT need steroid/antihistamine premedication. These drugs will not prevent or alleviate these symptoms.
- MILD REACTIONS – hives, nasal congestion, itching, mild shortness of breath can be performed at any facility and require the premedication as described below.
- SEVERE REACTIONS – laryngeal edema, severe shortness of breath, or anaphylactoid response need to be discussed with a radiologist prior to scheduling to determine if an alternative test can answer the clinical question. Scan location in these instances would depend on the clinical scenario. Call (540) 741-1571 to speak to a radiologist.
What about patients with history of anaphylaxis?
- Patients with prior severe life-threatening reaction to ANY substance, other than iodinated contrast, that required hospitalization are recommended to have our standard premedication protocol prior to iodinated IV contrast injection.
- Patients with prior anaphylactic reactions to imaging contrast agents (ex: iodinated contrast for CT, gadolinium for MRI) need to be discussed with a radiologist prior to scheduling to determine if an alternative test could be performed. This includes any reaction that required urgent medical care. Call (540) 741-1571 to speak to a radiologist.
What is the suggested premedication protocol? Where can these patients be imaged?
- Prednisone: 50 mg by mouth at 13 hours, 7 hours, and 1 hour before contrast media injection.
- Diphenhydramine (Benadryl®): 50 mg by mouth 1 hour before contrast medium
PLEASE NOTE: Patients receiving premedication can be scheduled at any of our locations EXCEPT for MINS (Medical Imaging of North Stafford).
Any patients requiring Benadryl premedication will need to be accompanied by a driver due to the associated drowsiness from this medication. Patients receiving premedication can be scheduled at any of our locations EXCEPT for MINS (Medical Imaging of North Stafford).