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Finding the right tests…
CT Scan
CT cisternography images the CSF-filled cisterns around your brain after contrast is introduced directly into the fluid around your spinal cord through a lumbar puncture. Doctors order it mainly for suspected cerebrospinal fluid leaks, such as clear, watery drainage from the nose after a head injury, sinus surgery, or without any obvious cause. As the contrast mixes with your spinal fluid and reaches the base of the skull, a CT scan can pinpoint the exact spot where fluid is escaping through a bone defect. This scan is usually done after a plain high-resolution CT has already shown one or more possible defect sites that need to be confirmed.
There's no lab measurement from this scan. A radiologist watches for contrast leaking out of the CSF space into the nose, sinuses, or middle ear, which confirms both that a leak exists and exactly where it is. The report describes the leak site rather than giving a number.
Cisterns are the fluid-filled spaces around your brain where cerebrospinal fluid, or CSF, normally collects. This scan uses contrast dye placed directly into that fluid to make a leak visible on CT.
- A small amount of iodine-based contrast is injected into the spinal fluid through a lumbar puncture, similar to a spinal tap - You're positioned so the contrast flows upward and pools around the base of the skull - A CT scan then captures images while the contrast is in the cisterns, showing whether it escapes through a bone defect
The main reason is a suspected CSF leak, most often causing clear fluid to drip from the nose or ear. According to NIH's StatPearls resource, most CSF leaks follow head trauma, with a smaller share caused by procedures such as sinus or pituitary surgery. Cisternography is typically brought in when a plain scan has already found more than one possible defect and doctors need to work out which one is actually leaking, or when a defect is present without a clear leak on the initial images.
It's injected into the fluid around your spinal cord through a lumbar puncture, much like a spinal tap, rather than through a vein in your arm.
Most people feel a brief sting from the local anaesthetic and some pressure during the puncture. Ask the centre what to expect and how they manage discomfort during the procedure.
A regular head CT can show a bone defect, but it can't always confirm whether fluid is actively leaking through it. Cisternography adds contrast into the CSF itself so a leak becomes visible.
Clear, watery drainage from the nose or ear, especially after a head injury, sinus surgery, or without any clear cause, is the most common reason. Tell your doctor if you notice a salty taste at the back of your throat, which can be a sign of CSF drainage.
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.
Yes, positioning helps the contrast flow to the area being checked. The centre will explain exactly what's needed before and during your scan.
As with any lumbar puncture, there's a small chance of headache, discomfort at the injection site, or a reaction to the contrast. Discuss your specific risk with your doctor beforehand.
It's considered a reliable method for localizing CSF leaks, but no test finds every leak every time. Your doctor may combine it with other imaging, like MRI cisternography, if the picture stays unclear.