Fractional Anisotropy Predicts Shunt Responsiveness in Normal Pressure Hydrocephalus: A DTI-Based Clinical Study
Francesco Corrivetti1, Matteo de Notaris1, Carmine Franco Muccio2
1Unit of Neurosurgery, University Hospital "San Giovanni di Dio e Ruggi D'Aragona", University of Salerno, Salerno, Italy.
Background:
Normal Pressure Hydrocephalus (NPH) is a treatable form of dementia that can mimic other neurodegenerative disorders. Diffusion tensor imaging (DTI) has emerged as a promising tool to assess white matter alterations in NPH. This study investigated the diagnostic role of Fractional Anisotropy (FA) values and their relationship with clinical outcome.
Methods:
Nineteen patients with probable NPH underwent preoperative MRI with DTI sequences and cerebrospinal fluid (CSF) tap test. Responders were treated with shunt surgery. FA maps were generated, and regions of interest (ROIs) were placed in the periventricular white matter, corpus callosum (genu and splenium), and cerebral peduncles.
Results:
Of the 19 patients, 14 responded to the tap test and 12 underwent shunting. FA values were significantly lower in non-responders. Within responders, triventricular-shaped ventricular enlargement showed higher FA values than the communicating type. The corpus callosum demonstrated the lowest FA values among responders, while triventricular enlargement correlated with better postoperative outcomes.
Conclusions:
FA represents a reliable marker of white matter integrity in NPH. Higher values, particularly in triventricular enlargement, were associated with favorable surgical outcomes. Incorporating FA analysis into routine MRI protocols could improve diagnostic accuracy and guide treatment planning in NPH patients.
