Magnetic resonance imaging (MRI)

What it is

Magnetic resonance imaging (MRI) is an imaging test that uses magnetic fields and radio waves (not radiation) to create detailed pictures of the brain. It is a mainstay for evaluating hydrocephalus, its cause, and the surrounding anatomy.

Understanding Magnetic resonance imaging (MRI)

MRI provides excellent detail of the brain's structure, allowing the team to assess ventricle size, identify the level and cause of a blockage (such as aqueductal stenosis, a tumor, or a malformation), and evaluate associated conditions. Because it does not use radiation, MRI is well suited to children who may need repeated imaging, though it takes longer than CT and young children may need sedation to stay still. Specialized MRI sequences, including CSF flow studies (cine phase-contrast MRI), can assess CSF movement — for example, to evaluate flow through the aqueduct or across an ETV opening. MRI is central to diagnosis and treatment planning.

Why it matters

Understanding MRI helps families see why this detailed, radiation-free test is central to evaluating hydrocephalus — showing the cause and level of a blockage and guiding treatment — while recognizing it takes longer and may require sedation in young children.