Periventricular hyperintensity in children with hydrocephalus.

Area of Science:

• Pediatric neurology
• Neuroimaging
• White matter diseases

Background:

• Children with hydrocephalus often exhibit a periventricular white matter hyperintensity (halo) on MRI.
• The cause of this halo has been debated, with two main hypotheses: pulsatile cerebrospinal fluid (CSF) flow or anatomical changes in white matter.

Purpose of the Study:

• To differentiate between the CSF flow and anatomical change hypotheses for the hydrocephalus halo.
• To investigate the underlying mechanisms of the halo using advanced neuroimaging techniques.

Main Methods:

• A multicenter study compared 19 children with hydrocephalus to 52 controls.
• Ventricle enlargement was quantified using the frontal-occipital horn ratio.
• Diffusion tensor imaging (DTI) analyzed fractional anisotropy (FA), mean diffusivity, axial diffusivity, and radial diffusivity in the corpus callosum and posterior limb of the internal capsule.

Main Results:

• The halo was present in 16/19 hydrocephalus patients but absent in controls.
• Hydrocephalus patients showed significantly decreased FA and increased mean/radial diffusivity in the corpus callosum.
• Alterations in FA and axial diffusivity were also observed in the posterior limb of the internal capsule, correlating with ventricle size.

Conclusions:

• The study's findings strongly support the hypothesis that the halo in pediatric hydrocephalus results from structural white matter changes.
• These structural changes, rather than pulsatile CSF flow, are the primary cause of the observed periventricular hyperintensity.