Fig 8. A, Narrow-necked aneurysm in 3D-TOF. Loss of signal intensity is observed in the aneurysm sac because of disturbed flow predominant in the center and proximal border of the sac and neck. B, The same aneurysm coiled with a 20% VER without silicon. Coils cause a major disturbance in the flow and a major loss of signal intensity explaining the overestimation of filling with 3D-TOF evaluations.