Evaluation of CSF leaks: High-resolution CT compared with contrast-enhanced CT and radionuclide cisternography

BACKGROUND AND PURPOSE: Radiologic evaluation of CSF leaks is a diagnostic challenge that often involves multiple imaging studies with the associated expense and patient discomfort. We evaluated the use of screening noncontra st high-resolution CT in identifying the presence and site of CSF rhinorrhe a and otorrhea and compared it with contrast-enhanced CT cisternography and radionuclide cisternography. METHODS: We retrospectively reviewed the imaging studies and medical record s of all patients who were evaluated for CSF leak during a 7-year period. F orty-two patients with rhinorrhea and/or otorrhea underwent high-resolution CT of the face or temporal bone and then had CT cisternography and radionu clide cisternography via lumbar puncture. The results of the three studies were compared and correlated with the surgical findings in 21 patients. RESULTS: High-resolution CT showed bone defects in 30 of 42 patients (71%) with CSF leak. High-resolution, radionuclide cisternography and CT cisterno graphy did not show bone defects or CSF leak for 12 patients (29%) who had clinical evidence of CSF leak. Among the 30 patients with bone defects, 20 (66%) had positive results of their radionuclide cisternography and/or CT c isternography. For the 21 patients who underwent surgical exploration and r epair, intraoperative findings correlated with the defects revealed by high -resolution CT in all cases, High-resolution CT identified significantly mo re patients with CSF leak than did radionuclide cisternography and CT ciste rnography, with a moderate degree of agreement. CONCLUSION: Noncontrast high-resolution CT showed a defect in 70% of the pa tients with CSF leak, No radionuclide cisternography or CT cisternography s tudy produced positive results without previous visualization of a defect o n high-resolution CT. CT cisternography and radionuclide cisternography may be reserved for patients in whom initial high-resolution CT does not ident ify a bone defect or for patients with multiple fractures or postoperative defects.