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Hemodynamically self-corrected ΔADC analysis in idiopathic normal pressure hydrocephalus
Marina Takatsuji-Nagaso1, Tosiaki Miyati2, Naoki Ohno2
11 Department of Radiology, Kouseiren Takaoka Hospital , Takaoka, Toyama , Japan.
The British Journal of Radiology
|February 15, 2019
Summary
Idiopathic normal pressure hydrocephalus (iNPH) shows increased hemodynamic-independent water fluctuation due to altered brain biomechanics. This finding aids in understanding iNPH and its effects on brain tissue.
Area of Science:
- Neuroimaging
- Biophysics
- Neurology
Background:
- Idiopathic normal pressure hydrocephalus (iNPH) is characterized by increased cerebrospinal fluid volume and ventricular dilation.
- The exact mechanisms causing brain water fluctuation in iNPH remain unclear.
- Previous studies suggest hemodynamic factors contribute to water fluctuation, but independent contributions are less understood.
Purpose of the Study:
- To investigate the cause of heightened brain water fluctuation in iNPH.
- To assess hemodynamic-independent changes in apparent diffusion coefficient during the cardiac cycle (ΔADC) in iNPH patients.
- To differentiate iNPH from other conditions with similar ventricular enlargement.
Main Methods:
- Utilized electrocardiographically synchronized diffusion echo-planar imaging (b = 0, 500, 1000 s/mm²) in healthy volunteers, patients with atrophic ventricular dilation, and iNPH patients.
- Measured cardiac cycle ΔADC and maximum ADC (ADCpeak) in frontal white matter.
- Calculated self-corrected ΔADC by dividing ΔADC by ADCpeak to account for perfusion-related diffusion and isolate hemodynamic-independent changes.
Main Results:
- Self-corrected ΔADC was significantly elevated in the iNPH group compared to healthy controls and the atrophic ventricular dilation group.
- No significant differences in ADCpeak values were observed among the three groups, indicating perfusion was not the primary driver of the observed ΔADC changes.
- The findings suggest altered biomechanical properties of the brain contribute to increased water fluctuation in iNPH.
Conclusions:
- The increased self-corrected ΔADC in iNPH is attributed to alterations in the brain's biomechanical properties.
- Self-corrected ΔADC analysis provides valuable insights into hemodynamically independent water fluctuation and perfusion in iNPH.
- This analytical approach offers simultaneous information on biomechanical properties, perfusion, and water fluctuation, advancing understanding of iNPH pathophysiology.
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