Cerebrospinal fluid rhinorrhea: evaluation with metrizamide cisternography.

Metrizamide computed tomographic cisternography was used to examine 27 patients (19 males and eight females, 14-59 years old) clinically suspected of having cerebrospinal fluid fistulae with rhinorrhea. Twenty-one fistulae were traumatic and six were spontaneous. Five to 6 ml of metrizamide (or lopamidol, two cases) were injected by lumbar puncture at a concentration of 185-200 mg I/ml for direct coronal and axial computed tomographic sections of the skull base. Cerebrospinal fluid rhinorrhea was present at the time of examination in 12 of 27 cases. Results were evaluated according to three criteria: (1) metrizamide passage through the bony and dural defect; (2) demonstrable site of the fracture and/or bony defect; and (3) metrizamide visualized within a paranasal sinus, nasal cavity, or cotton pledget. The examination was considered positive when criterion 1 alone was present and when 2 and 3 were associated. In 15 of 27 cases, cisternography was positive, with the exact site of cerebrospinal fluid leakage demonstrated in 10 patients. In six cases, the results were not definitive; only one of the criteria (2 or 3) was fulfilled. In six cases, cisternography was normal. Seventeen patients underwent surgery. The site of cerebrospinal fistulae was ethmoidal in nine cases, frontoethmoidal in seven, sphenoidal in two, and sphenoethmoidal in one. The relative value of metrizamide computed tomographic cisternography compared with other diagnostic studies, polytomography, positive or negative contrast studies, and radionuclides, is discussed. Diagnostic pitfalls include artifacts and partial volume effect.