Change in Morphological Features of Enlarged Subarachnoid Spaces Following Treatment in Idiopathic Normal Pressure Hydrocephalus

Background Focally enlarged sulci (FES) are areas of proposed extraventricular fluid entrapment that may occur within idiopathic normal pressure hydrocephalus (iNPH) with radiographic evidence of disproportionately enlarged subarachnoid‐space hydrocephalus (DESH), and should be differentiated from atrophy. Purpose To evaluate for change in FES size and pituitary height after shunt placement in iNPH. Study type Retrospective. Subjects A total of 125 iNPH patients who underwent shunt surgery and 40 age‐matched controls. Field Strength/Sequence 1.5 T and 3 T. Axial T2w FLAIR, 3D T1w MPRAGE, 2D sagittal T1w. Assessment FES were measured in three dimensions and volume was estimated by assuming an ellipsoid shape. Pituitary gland height was measured in the mid third of the gland in iNPH patients and controls. Statistical tests Wilcoxon signed‐rank test for comparisons between MRI measurements; Wilcoxon rank sum test for comparison of cases/controls. Significance level was P