Fig. 3

Female patient aged 65 years old presented by memory disturbance, gait apraxia, and urinary incontinence. MRI (a) axial FLAIR at the level of the lateral ventricle showing hydrocephalus (Evan index = 0.33). b Sagittal T2 WI showing the signal void sign at the aqueduct (white arrow). c 3D DRIVE image showing patent normal aqueduct. d CSF flow in the aqueduct of Sylvius as shades of white. Sagittal phase image in systole showing (e) velocity-time curve showing CSF in both diastole (above the base line) and systole (below the base line). PDV = 3.9 cm/s, PSV = 5.8 cm/s. Vmax = (3.9 + 5.8)/2 = 4.85 cm/s. f CSF flow curve associated table demonstrating the following: forward flow volume = 131 μl, and backward flow volume = 156 μl, and so the SV = (131 + 156)/2 = 143.5 μl/cycle. Aqueduct area = 0.122 cm². So the maximum flow was calculated as following: maximum flow = 4.85 × 0.122 = 0.5917 cm³/s. The diagnosis is hyperdynamic CSF circulation consistent with NPH