MR diagnosis of CSF fistulas using a 3D-CISS sequence.

We compared a new MR method for diagnosis of CSF fistulas with CT cisternography. Material and methods: In a prospective case study we examined 35 patients with posttraumatic CSF fistulas and compared the results with the intraoperative findings. The MR investigation was performed using a 1.0T whole body MR-system. We used a strongly T-2*-weighted 3D-CISS sequence. The examinations were performed in prone position, in patients with severe CSF rhinorrhoea additionally in supine position. Results: The sensitivity and specificity of the MR method (88.9% and 95.1%) is higher compared with CT cisternography (77.8% and 87.8%). The reason for the lower sensitiviy of CT compared with MRI are complex fracture systems, involving several paranasal cavities in patients with false positive results in CT cisternography. Reasons for the lower specificity of CT cisternography are false negative results in patients with small dural lesions below 2 mm(2). Conclusion: Using a new method MRI can detect CSF fistulas. The MR method is superior to CT cisternography, is noninvasive, the administration of contrast and agent is no longer neccessary.