Changes in Ventricular and Cortical Volumes following Shunt Placement in Patients with Idiopathic Normal Pressure Hydrocephalus

• Published in: American journal of neuroradiology : AJNR Vol. 42; no. 12; pp. 2165 - 2171
• Main Authors: Cogswell, P M, Murphy, M C, Senjem, M L, Botha, H, Gunter, J L, Elder, B D, Graff-Radford, J, Jones, D T, Cutsforth-Gregory, J K, Schwarz, C G, Meyer, F B, Huston, 3rd, J, Jack, Jr, C R
• Format: Journal Article
• Language: English
• Published: United States American Society of Neuroradiology 01.12.2021
• Subjects: Adult Brain; Aged; Editor's Choice; Female; Functional; Humans; Hydrocephalus - pathology; Hydrocephalus, Normal Pressure - diagnostic imaging; Hydrocephalus, Normal Pressure - pathology; Hydrocephalus, Normal Pressure - surgery; Magnetic Resonance Imaging - methods; Male; Retrospective Studies; Treatment Outcome; Ventriculoperitoneal Shunt
• ISSN: 0195-6108; 1936-959X
• DOI: 10.3174/ajnr.A7323

While changes in ventricular and extraventricular CSF spaces have been studied following shunt placement in patients with idiopathic normal pressure hydrocephalus, regional changes in cortical volumes have not. These changes are important to better inform disease pathophysiology and evaluation for copathology. The purpose of this work is to investigate changes in ventricular and cortical volumes in patients with idiopathic normal pressure hydrocephalus following ventriculoperitoneal shunt placement. This is a retrospective cohort study of patients with idiopathic normal pressure hydrocephalus who underwent 3D T1-weighted MR imaging before and after ventriculoperitoneal shunt placement. Images were analyzed using tensor-based morphometry with symmetric normalization to determine the percentage change in ventricular and regional cortical volumes. Ventricular volume changes were assessed using the Wilcoxon signed rank test, and cortical volume changes, using a linear mixed-effects model ( < .05). The study included 22 patients (5 women/17 men; mean age, 73 [SD, 6] years). Ventricular volume decreased after shunt placement with a mean change of -15.4% ( < .001). Measured cortical volume across all participants and cortical ROIs showed a mean percentage increase of 1.4% ( < .001). ROIs near the vertex showed the greatest percentage increase in volume after shunt placement, with smaller decreases in volume in the medial temporal lobes. Overall, cortical volumes mildly increased after shunt placement in patients with idiopathic normal pressure hydrocephalus with the greatest increases in regions near the vertex, indicating postshunt decompression of the cortex and sulci. Ventricular volumes showed an expected decrease after shunt placement.