Computed tomography (CT) cisternography is an imaging technique used to diagnose CSF rhinorrhea or CSF otorrhea (CSF leaks), as CT allows the assessment of the bones of the base-of-skull.
- pre-contrast CT is performed with thin slices
- 3-10 mL of an iodinated nonionic low-osmolar contrast agent is installed into thecal sac after lumbar puncture
- the patient is then tilted with foot-end elevation and a CT scan is performed with thin slices; manoeuvres that provoke an active leak, such as head hanging or sneezing, are performed to visualise intermittent or occult leaks
- post-contrast images are then compared with the pre-contrast image to see where the CSF and the contrast are leaking out
- radionuclide cisternography is more sensitive but has poor anatomic resolution compared to CT cisternography