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 non-ionic low-osmolar contrast agent is installed into the 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 visualize 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