Hydrocephalus is characterized by excessive accumulation of cerebrospinal fluid (CSF) in the ventricles of the brain. One of the forms of hydrocephalus is called "normal pressure", although one of the main signs is precisely an alteration of the intracranial pressure (ICP), it is here called active hydrocephalus (HA). Although MRI is the reference radiological modality for the characterization of HA. The Evan's and DESH index are radiological diagnostic criteria based on the dilation and morphology of the CSF compartments. These morphological indices remain insensitive and specific. In recent years, advances in Phase Contrast (MRI-PC) and Diffusion (MRI-DTI) MRI have generated new biomarkers of brain viability. The aim of this study is to characterize by MRI the impact of hydrocephalus on brain fluids and tissues.

Inclusion Criteria:

• For Patients with hydrocephalus:
• Age > 55,
• Ventricular dilation: Evans Index > 0.3;
• Patients with cognitive impairment, and gait disturbances and/or urinary incontinence or a combination of these three symptoms;
• Absence of other neurological diseases that could cause ventriculomegaly, information and non-opposition.
• For Controls:
• Age ≥ 55;
• No ventricular dilation: Evans Index < 0.3;
• Individuals who have no neurological or psychiatric disease;
• No neurological deficit.
• No history of neurosurgery or head trauma;
• signed informed consent;
• affiliation to a social security scheme.

Exclusion Criteria:

• All patients who have a neurological disease other than active hydrocephalus will be excluded;
• Individuals unable to sign or understand consent;
• Individuals with psychiatric, neurological or medical development;
• Individuals under treatment with psychoactive drugs;
• Individuals who cannot tolerate an MRI examination;
• Any individual with implant, pacemaker, prosthesis and ferromagnetic object