The diagnosis of CSF rhinorrhea by metrizamide CT scanning

A case of cerebrospinal fluid rhinorrhea is presented in which routine diagnostic evaluation failed to disclose the site of leakage. Computerized tomography (CT) scanning with metrizamide, a nonionic contrast medium, provided not only documentation of the leak but also demonstrated the actual sinus involved. Metrizamide cisternography with CT scanning is a valuable technique in the evaluation of CSF rhinorrhea. It may only be used when an active leak is present. The patient described in this report lost several drops of CSF from the nose per minute in the face-down position. Neurotoxicity may be avoided by routine pre-examination medication with valium or phenobarbital. Mixing of the contrast agent with CSF is diminished by injecting in the subarachnoid space at C1-C2. The methods used in this examination and their indications are described, and the literature concerning metrizamide toxicity and pharmacologic properties reviewed.