A fistulogram (sometimes called a sinogram) is a specialized, live X-ray scan (fluoroscopy) used to check an abnormal tunnel or passageway in your body, known as a fistula or sinus tract. A fistula can form between two organs, or between an organ or bone and the surface of your skin (often due to chronic infection or surgery).
During the procedure, a liquid dye (contrast) is gently injected into the opening of the tract on your skin. X-ray images are taken as the dye fills the tunnel, showing exactly where the tract goes and whether it connects to any internal organs or bones.
Common Indications for a Fistulogram
- Mapping the path of an abnormal tract (fistula) draining fluid or pus onto the skin.
- Investigating suspected connections between organs, such as between the bowel and bladder or skin.
- Checking for sinus tracts arising from chronic bone infections (osteomyelitis).
- Assessing healing or leakage after surgeries.
- Checking the integrity of a surgically created fistula (like an AV fistula for dialysis) before use.
What exactly does a fistulogram show?
The scan shows the exact path, length, and depth of the abnormal tunnel. It also shows if the tract branches out, ends in a blind pocket, or connects to deeper organs, blood vessels, or bones.
How should I prepare for a fistulogram?
No special diet or fasting is required for most scans. If your fistula is located in your abdomen or pelvis, you may be asked to fast or follow a clear liquid diet the day before. Dress in comfortable, loose clothing that is easy to remove.
Do I need to stop taking medication?
No. Continue all your usual medications. If you have any allergies—especially to contrast dye, iodine, or latex—tell your referring doctor and the scan team beforehand.
What happens when I arrive for my scan?
You will change into a hospital gown. The radiographer will guide you to the fluoroscopy room and ask you to lie down on the X-ray table. The area around the opening of the fistula on your skin will be cleaned with a sterile solution.
How is the procedure performed?
You will lie down on the X-ray table. The doctor will gently insert a small, soft plastic tube (catheter) or a blunt-tipped needle into the opening of the fistula on your skin. They will slowly inject the contrast dye through the tube. The radiographer will take live X-ray images from different angles to track where the fluid flows. Once the images are complete, the tube is removed, and the area is cleaned and bandaged.
How long does a fistulogram take?
The procedure typically takes about 20 to 40 minutes, depending on the size and complexity of the abnormal tract.
Is there any discomfort?
You may feel a mild pressure or a warm sensation as the contrast dye is injected to fill the tract. While it can be uncomfortable, it is generally not painful. Let the team know if the pressure becomes painful, and they will adjust the injection speed.
Are there risks?
Yes, but they are very low. There is a small risk of introducing infection into the tract, causing temporary worsening of pain, or a mild allergic reaction to the contrast dye. The scan uses a low dose of radiation, similar to a few months of natural background radiation.
Can children have this scan?
Yes. Children can have this scan safely if requested by their doctor. The team uses smaller catheters and lower radiation doses tailored for children.
Can I have this scan if I am pregnant?
Pregnancy Precaution
Tell your doctor or radiographer if you are pregnant or think you might be. Because this scan uses X-rays, alternative tests (like MRI or ultrasound) are usually considered during pregnancy to protect the unborn baby from radiation.
When will I get my results?
The radiologist will review the images immediately. A written report and the scan images will be sent to your referring doctor or handed to you within a few hours.
What if the scan finds something?
The scan is done specifically to map the tract. Once your referring doctor (often a surgeon) receives the map, they will discuss treatment options with you, which may include surgery to close the tract or antibiotic therapy.
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.
Questions to ask the fluoroscopy team
- What exact question should this examination answer, and is a radiation-free or non-invasive alternative suitable?
- Which contrast route and agent will be used, and what preparation, pregnancy, breastfeeding, allergy, kidney, diabetes, or medicine instructions apply to me?
- Will a catheter, internal examination, sedation, or pain relief be needed, and may I stop the procedure if I am uncomfortable?
- What symptoms require urgent help afterward, when will the signed report be ready, and who will explain the result?
Sources and further reading
- RadiologyInfo.org: Fluoroscopy
- American College of Radiology: Manual on Contrast Media
- RadiologyInfo.org: Radiation safety for children
Conclusion
A fistulogram may outline part of a tract, but narrow branches, blocked segments, or communication beyond the contrast-filled lumen can be missed. Bring dressings if requested and ask whether CT, MRI, ultrasound, endoscopy, or surgery is also needed.