The Role of the Glymphatic System Avaluated Thourgh mr Imaging in the Diagnosis and Management of NPH

The goal of this observational study is to evaluate the role of DTI-ALPS in the diagnostic and therapeutic management of NPH The main questions it aims to answer are: * Whether the glymphatic system (GS) is actually impaired in NPH * Whether DTI-ALPS index can predict the positive response to tap test (TT) and to ventriculo-peritoneal shunt (VPS) surgery. A healthy control group of patients (HC group) matched for age with the study group, will undergo MR with DTI-ALPS study