CSF rhinorrhea from a transclival meningocele demonstrated with metrizamide CT cisternography

A 63-year-old woman with a 10-year history of intermittent cerebrospinal fluid (CSF) rhinorrhea was found to have a transclival meningocele. After pluridirectional tomography demonstrated a bone defect in the clivus, the diagnosis was established by means of computerized tomography (CT) by comparing the absorption coefficients of a soft-tissue mass within the sphenoid sinus before and after the injection of metrizamide into the lumbar subarachnoid space. An increase of 39 absorption units clearly indicated the movement of CSF from the prepontine subarachnoid space into the sphenoid sinus. This case illustrates the value of metrizamide CT cisternography in the evaluation of patients with CSF rhinorrhea.