Comparison of different MR venography techniques for detecting transverse sinus stenosis in idiopathic intracranial hypertension.

Cerebral venous outflow abnormalities, as transverse sinuses (TSs) stenosis,may underlie a picture of idiopathic intracranial hypertension (IIH). To identify the best non-invasive MR venography (MRV) technique for exploring the disturbance of flow of TSs in IIH patients, we compared three dimensional phase contrast (3-DPC) MRV images, acquired with different velocity encodings (15 and 40 cm/s) with two-dimensional time-of-flight (2D-TOF) MR images in 6 subjects with IIH and 12 age-matched normal controls. In both groups, we also measured flow velocity in TSs by using single slice 2D-CINE PC acquisitions. In all subjects with IIH, 3D-PC showed marked flow disturbance in the mid-lateral portion of both TSs when velocity encoding (VENC) was set to 15 cm/s while only a slightly irregular flow in TSs was detected when VENC was set to 40 cm/s or when 2D-TOF was used. By contrast, 3D-PC (VENC 15 and 40) and 2D-TOF techniques were comparable in detecting TS signal flow in normal controls. Measures of flow velocity, by using 2D-CINE PC, revealed a three-fold increase of velocity at the level of the flow disturbance in IIH patients compared to normal controls (p<0.0001), suggesting a marked stenosis of mid-lateral portion of TSs in these patients. Setting the VENC to 15 cm/s on 3D-PC MRV may represent the best technical approach for visualizing disturbances of flow in TSs in subjects with symptoms suggestive of IIH.