Finding the right tests…
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Finding the right tests…
CT Scan
CT sinogram/fistulogram maps a sinus tract or fistula, an abnormal channel that opens onto your skin, often after surgery, an infection, or a chronic wound that will not heal. A small catheter is placed into the opening and a contrast dye is injected directly into the tract, then CT images are taken to trace its path. Unlike a standard contrast CT, the dye goes straight into the tract rather than into a vein, so it clearly outlines the channel's course, length, and any connection to deeper organs or cavities. This helps your doctor understand what is causing the wound to persist and plan treatment.
This scan traces the path, length, and depth of a sinus tract or fistula from its skin opening, and checks whether it connects to an organ, cavity, or area of infection. Your report describes the tract's course and any abscess or foreign material found along the way.
A sinus tract is a channel with one opening, usually on the skin. A fistula is an abnormal connection between two structures, such as the bowel and the skin. Both can develop after surgery, an infection, or conditions like Crohn's disease, and both can be mapped the same way.
A thin catheter is gently placed into the tract's skin opening. Contrast dye is injected directly through the catheter, not into a vein, and CT images are taken as the dye fills the channel.
- The course and length of the tract - Whether it connects to the bowel, bladder, or another organ - Any pocket of infection or abscess nearby - Retained material inside the tract, if present
This scan is often done for a wound or opening that will not heal, especially after surgery, or to check whether a fistula has closed after treatment. It is generally avoided when there are signs of a severe, spreading infection, since injecting a tract in that setting can be unsafe.
Reactions to the contrast dye used here are uncommon but possible, so tell your doctor about any past allergic reaction. As with any CT scan, it involves a small amount of radiation, so tell the centre if you are or might be pregnant.
A thin catheter is placed into the skin opening of the tract, and the dye is injected directly through it, not into a vein like most contrast CT scans.
A sinus tract has one opening, usually on the skin, and ends blindly or in an abscess. A fistula is an abnormal connection between two structures, such as the bowel and the skin. Both are imaged the same way.
You may feel some pressure as the catheter is placed and the contrast is injected. Tell the technologist if you feel significant discomfort during the procedure.
If there are signs of a severe or spreading infection, this scan may not be appropriate at that time. Your doctor will assess whether it's safe to proceed.
This page is general information about the test, not medical advice. Your own report's reference ranges apply — please discuss your results with your doctor.
It maps the tract and checks for connections to deeper structures or hidden infection, which can help explain a non-healing wound. Your doctor will interpret the findings alongside your history.
A regular contrast CT injects dye into a vein. This scan injects dye directly into the tract itself through a catheter, which outlines the channel more precisely.
Preparation can vary depending on the location of the tract. Ask your doctor or the centre for instructions specific to you.