MRI CSF Flowmetry in Differentiation between Normal Pressure Hydrocephalus and Involutional Brain Atrophy

Background: Phase contrast (PC) cine magnetic resonance imaging (MRI) is a valuable imaging method in estimating cerebrospinal fluid (CSF) dynamics that concerns several disease processes. The aim of this work was to estimate the usefulness of cine- PC MRI CSF flowmetry in patients with normal pressure hydrocephalus (NPH) and to differentiate them from involutional brain atrophy.

Methods: This prospective study included 30 patients with overlapping symptoms of NPH with involutional brain changes and 10 healthy volunteers as controls with no clinical symptoms and normal imaging results. Two imaging planes were applied: one in the sagittal plane with plane velocity encoded in the caudo-cranial direction for a qualitative assessment & one in the axial plane with through-plane velocity encoded in the caudo-cranial direction for quantitative measurements.

Results: Pathological CSF flow dynamics in NPH, peak systolic velocity and systolic SV values were greater than controls; these findings imply that cases with NPH had hyper dynamic aqueductal CSF flow. In cerebral atrophy, blood flow to the brain is reduced; we reported lower peak systolic velocity and lower SV values compared to healthy participants, suggesting hypo dynamic CSF circulation.

Conclusion: PC MRI CSF flowmetry is shown to be a valuable method especially in the elderly, in diagnosing NPH & differentiating it from age associated brain atrophy where differentiation based on conventional and clinical radiological basis may be complicated.