In fluoroscopy, a special dye called contrast media is sometimes used to help create a clearer view of internal structures like blood vessels, organs, the gastrointestinal tract, or joints. This dye helps doctors better distinguish and outline these areas on the imaging screen, making it easier to diagnose or monitor specific conditions.
Depending on the procedure, contrast can be administered in different ways, such as orally, rectally, or through a vein. For more detailed information on contrast, please visit our comprehensive FAQ section on contrast media.
About this scan
Filling the Consent form and Questionnaire
Complete a form noting any allergies, past experiences with contrast, and your consent to proceed. This preparation helps to ensure that the contrast is used safely and effectively.
If you have additional questions or concerns, don’t hesitate to discuss them with your healthcare provider before agreeing to the procedure.
Before your appointment
Will I have to fast?
Fasting is not required solely because contrast is used. It depends on the examination, aspiration risk, and whether sedation or anesthesia is planned. Follow the center's exact instructions.
During the scan
What are the types of contrast used in fluoroscopy?
Contrast choice depends on the body system and route. Barium and water-soluble iodinated agents may be swallowed or given rectally; iodinated contrast can also be injected into blood vessels, joints, the bladder, uterus, ducts, or fistulas. Kidney-function assessment is mainly relevant when iodinated contrast enters the bloodstream and is based on individual risk rather than required for everyone.
Are there any side effects from the contrast agent?
Effects depend on route and agent. Warmth or a metallic taste can occur with intravenous iodinated contrast; barium more often causes constipation or abdominal discomfort and can be dangerous if it leaks through a perforation or is aspirated. Allergic-like reactions mainly concern agents entering the bloodstream. Report the exact contrast and reaction you previously experienced; shellfish or "iodine" allergy alone does not identify a specific contrast allergy.
Safety and special situations
What are the important limitations and safety checks?
Fluoroscopy shows movement or anatomy during a specific examination, but it does not guarantee a diagnosis or exclude every abnormality. Image quality and interpretation can be limited by positioning, movement, body size, retained contrast, overlying structures, incomplete filling, or the patient's ability to complete the study. Further endoscopy, ultrasound, CT, MRI, laboratory testing, or tissue sampling may still be needed.
Fluoroscopy uses ionising radiation. Dose varies with the body area, examination complexity, equipment, patient size, and imaging time; the team should use the lowest exposure that still answers the clinical question. Tell the team before the examination if you are or may be pregnant. Pregnancy does not create a universal ban: the referrer and imaging team should decide whether to defer, modify, or proceed when the expected benefit outweighs the risk.
Contrast and preparation are procedure-specific. Barium, water-soluble iodinated contrast, intravenous contrast, and contrast placed into a joint, bladder, uterus, duct, or fistula have different risks. Tell the team about prior reactions, swallowing or aspiration problems, suspected perforation, kidney or thyroid disease, diabetes, medicines, and recent contrast studies. Do not fast, stop medicines, interrupt breastfeeding, or take bowel preparation or antibiotics based only on a general webpage; follow the center's written instructions.
Sources and summary
Sources and further reading
Conclusion
Contrast can make a fluoroscopic examination diagnostically useful, but agents and risks are not interchangeable. Safe selection depends on route, suspected perforation or aspiration, prior reaction, kidney and thyroid risk when relevant, pregnancy, and the precise clinical question.