Purpose: To study the clinical usefulness and sensitivity of MR cisternography as noninvasive study in the diagnosis of CSF fistula in patients with clinical diagnosis CSF rhinorrhea or otorrhea.
Method: Thirty-five patients with clinically diagnosed CSF leakage were examined for site of dural tear with MR cisternography with additional plain high-resolution CT in some cases from Jan. 1999 to Dec.2002. The MR imaging technique was performed as a heavily T2 weighted fast spin echo study with fat suppression in axial, coronal and sagittal projections. Criteria for positive results were demonstrable fistular tract connecting subarachnoid space to paranasal sinus/petrous bone, and/or dural discontinuity, and/or bone defect with pneumocephalus, and/or presence of brain herniation. Eighteen of the patients subsequently had exploratory surgery for fistula. Sensitivity analysis of the surgical results was compared with the findings at MR cisternography.
Result: MR cisternography showed significant correlation with surgical findings with sensitivity of 89%. Additional high resolution CT were complete agreement with site of fistular tract. The pathogenesis of CSF leakage was related to trauma (86%). The commonly found dural/bony defect and location of connecting fislular tract were cribriform plate and ethmoid sinus of 58%, 55% respectively.
Conclusion: In the presence of clinically diagnosed CSF leakage, the combination of MR cisternography and plain high-resolution CT are highly accurate in locating the site and extent of CSF fistula and should be considered a viable noninvasive alternative to CT cisternography and Tc-99m-DTPA cisternography.