 The lateral ventricles and the third ventricle are enlarged, not significantly changed since the previous study. The fourth ventricle appears normal size. In the mid to distal aqueduct there is a focal low signal area on 3D sagittal BFFE sequence (series 301, image 20/51) that may represent point of narrowing, but it could also represent partial volume artifact.Flow images demonstrates bidirectional flow signal anterior and posterior to the brainstem thorough the foramen magnum. However, there is no identifiable flow signal across the aqueduct.There are no diffusion abnormalities. There are scattered susceptibility signals throughout the brain, most likely due to old blood products.
1. Low signal intensity is seen in the mid to distal aqueduct on 3D BFFE sagittal scan. This may represent the point of narrowing of the aqueduct; however, it could also represent partial volume artifact.2. There is no flow signal across the aqueduct on phase contrast MRA.