Image AnalysisMR and cerebral MR venographies of the brain were performed on all subjects, using a 1.5 T scanner (GE Medical Systems, Milwaukee, WI). Brain MR consisted of sagittal T1- and transverse T2-weighted spin echo sequences with a slice thickness of 5 mm and an interslice gap of 1 mm. MRV was performed using 3D-PC techniques as described elsewhere . All brain MR and MR venographies were analyzed by the same neuroradiologist, who were blinded to each patient's history. We classified the transverse sinus (TS) stenosis (TSS) as present or absent. TSS was considered present when the signal flow was poor or lacking (flow gap) in the mid-lateral portion of the transverse sinus (unilateral TSS) or in both transverse sinuses (BTSS).