Diffusion tensor imaging in idiopathic normal pressure hydrocephalus: clinical and CSF flowmetry correlations

Area of Science:

• Neuroimaging
• White Matter Integrity
• Cerebrospinal Fluid Dynamics

Background:

• Idiopathic normal pressure hydrocephalus (iNPH) is a neurological disorder characterized by gait disturbance, urinary incontinence, and cognitive impairment.
• White matter changes are a hallmark of iNPH, but their precise characterization and correlation with clinical status remain areas of active research.
• Diffusion tensor imaging (DTI) is a non-invasive MRI technique sensitive to white matter microstructure.

Purpose of the Study:

• To analyze quantitative diffusion tensor imaging (DTI) parameters in patients with idiopathic normal pressure hydrocephalus (iNPH).
• To determine the correlation between DTI parameters, clinical scores (Mini-Mental State Examination, Frontal Assessment Battery), and cerebrospinal fluid (CSF) flowmetry data in iNPH patients.

Main Methods:

• Fifteen iNPH patients and 15 age-matched controls underwent DTI and CSF flowmetry.
• Quantitative DTI parameters (fractional anisotropy, mean diffusivity, axial diffusivity, radial diffusivity) were calculated in nine cerebral regions using atlas-based tract-mapping.
• DTI parameters were correlated with clinical scores and CSF flowmetry data in iNPH patients.

Main Results:

• Significantly lower fractional anisotropy in the forceps minor and motor cortex of iNPH patients compared to controls.
• Significantly higher mean axial diffusivity in the genu of the corpus callosum and forceps minor in iNPH patients.
• A correlation was observed between forceps minor fractional anisotropy and the Frontal Assessment Battery score; no significant correlations were found between DTI parameters and CSF flowmetry or Mini-Mental State Examination scores.

Conclusions:

• Diffusion tensor imaging (DTI) serves as a non-invasive biomarker for white matter alterations in idiopathic normal pressure hydrocephalus (iNPH).
• The forceps minor region demonstrates significant white matter changes and is a key area for DTI analysis in iNPH.
• DTI shows a stronger correlation with clinical status in iNPH compared to CSF flowmetry, supporting its integration into routine iNPH diagnostic protocols.