MR Evaluation of CSF Fistulae

Purpose: To evaluate the role of MR imaging in the localisation of cerebrospinal fluid (CSF) fistulae. Material and Methods: A total of 36 consecutive unselected patients with either clinically proven CSF leakage (n=26) or suspected CSF fistula (n=10) were prospectively evaluated by MR. All MR examinations included fast spin-echo T2-weighted images in the 3 orthogonal planes. Thin-section CT was performed following equivocal or negative MR examination. MR and CT findings were correlated with surgical results in 33 patients. Results: CSF fistula was visualised as a dural-bone defect with hyperintense fluid signal continuous with that in the basal cisterns on T2-weighted images. MR was positive in 26 cases, in 24 of which the fistula was confirmed surgically. In 2 patients the CSF leakage was directly demonstrated on MR. MR sensitivity of 80% compared favourably with the reported 46-81% of CT cisternography (CTC). No significant difference in MR sensitivity in detecting CSF fistula was found between active and inactive leaks Conclusion: MR is recommended as the first investigation for detecting a CSF fistula owing to its efficacy and to its freedom from the potential complications encountered with CTC.