Not for emergencies. For any urgent or life-threatening symptom, call 911 or go to the ER immediately. If you experience a reaction to contrast after a scan — call the imaging facility and seek emergency evaluation. DOD is not an emergency service.
CT With Contrast: What Patients Should Know
Many CT scan protocols use intravenous iodinated contrast agents to improve visualization of blood vessels, solid organs, and certain tissue types. Contrast CT requires kidney function assessment (eGFR) for patients at risk, and allergy history review before administration.
Educational content only. Contrast safety and protocol decisions are made by licensed providers and imaging facilities. DOD does not perform or interpret CT scans.
Quick Answer
CT with contrast uses an intravenous iodinated contrast agent to improve visibility of blood vessels, organ enhancement, and tissue characterization. Risks include contrast-associated kidney injury (especially with impaired kidney function) and allergic-type reactions. An eGFR test may be required before contrast CT. Metformin may need to be held. The ordering provider specifies whether contrast is needed. DOD can review CT order requests (with or without contrast) for eligible patients in supported states.
Types of CT Contrast
Intravenous (IV) Iodinated Contrast
Administered through a vein — highlights blood vessels and solid organ vascularity; most common CT contrast type
Oral Contrast
Ingested by the patient before the scan — opacifies the stomach and bowel to help differentiate bowel from other structures
CT Angiography (CTA)
Specifically timed IV contrast injection to image arteries or veins — requires precise contrast timing and bolus tracking
Rectal Contrast
Less commonly used — administered via rectum to opacify the colon in specific clinical situations
Kidney Function (eGFR) and CT Contrast
Patients with impaired kidney function may be at higher risk from iodinated IV contrast. The ACR Manual on Contrast Media provides guidance on eGFR thresholds and risk stratification for contrast CT. Many facilities require a recent eGFR/creatinine result before contrast administration in at-risk patients — typically patients with diabetes, chronic kidney disease, age over 60, hypertension, or a single kidney.
Lab Orders — eGFR and What Patients Should KnowFrequently Asked Questions — CT With Contrast
Sources
- ACR Manual on Contrast Media — American College of Radiology (ACR)
- Contrast Material — Patient Information — RadiologyInfo.org (ACR / RSNA)
- CT Scans — MedlinePlus (NIH)
Related Education and Order Pages
Need a Provider Review for a CT Scan Order?
$40 virtual provider review. Contrast appropriateness determined by reviewing provider.
Start Virtual Consult — $40Not for emergencies. Orders not guaranteed.
Educational content only. DOD does not perform or interpret CT scans. Contrast decisions are made by licensed providers and imaging facilities.