Brain stem venous congestion due to dural arteriovenous fistulas of the cavernous sinus

Background. Venous congestion of the brain stem due to dural arteriovenous fistulas (DAVFs) in the cavernous sinus is rare and presents therapeutic challenges. To assess the prognosis of patients with symptomatic DAVFs and brain stem dysfunction, we evaluated the degree of venous ischemia by examining pre- and post-treatment magnetic resonance images (MRI) in 2 patients presenting with venous congestion of the brain stem. Methods. A 56-year-old woman with left hemiparesis and a 70-year-old woman with gait disturbance attributable to right cavernous sinus DAVFs were referred to our hospital. In both cases, T2-weighted magnetic resonance imaging (MRI) disclosed a hyperintensity lesion in the brainstem due to venous congestion. Findings. Both patients underwent open surgery for direct embolization of the cavernous sinus because there were no approach routes for transvenous embolization. The patient whose pretreatment MRI demonstrated Gd enhancement continued to manifest neurological deficits and persistence of the abnormal hyperintensity on post-treatment T2-weighted MRI. In the other patient whose pretreatment MRI showed no Gd enhancement, treatment produced a complete response of her neurological deficit and disappearance of the abnormal hyperintensity area. Conclusions. We tentatively conclude that lesions corresponding to hyperintensity areas on non-Gd-enhanced, T2-weighted MRI may reflect a reversible condition whereas lesions identified as hyperintense areas on GD-enhanced T2-weighted MRI may be indicative of irreversibility.