Biological correlates of diffusivity in brain abscess

Area of Science:

• Neuroimaging
• Infectious Diseases
• Biophysics

Background:

• Restricted diffusion in brain abscesses is attributed to pus composition.
• Previous studies linked diffusion changes to cell density in tumors.

Purpose of the Study:

• To investigate the relationship between apparent diffusion coefficient (ADC) and pus characteristics in brain abscesses.
• To determine the primary factor responsible for restricted diffusion in brain abscesses.

Main Methods:

• Diffusion-weighted imaging (DWI) was performed on 41 patients with brain abscesses.
• Apparent diffusion coefficient (ADC) values were correlated with quantified viable cell density, viscosity, and protein content of abscess pus.
• Cell density was modeled within restricted and unrestricted lesion volumes.

Main Results:

• A significant inverse correlation was found between restricted ADC and viable cell density in both pyogenic and tuberculous brain abscesses.
• Mean restricted ADC was 0.65 ± 0.01 x 10⁻³ mm²/s for pyogenic and 0.60 ± 0.04 x 10⁻³ mm²/s for tuberculous abscesses.
• Viable cell density was identified as the main biological parameter influencing restricted diffusion.

Conclusions:

• Viable cell density is the primary determinant of restricted diffusion in brain abscesses.
• The etiological agent does not influence the relationship between cell density and diffusion restriction.
• DWI can effectively assess cellularity in brain abscesses.