Neuroimaging in rabies.

Area of Science:

• Veterinary Neurology
• Infectious Diseases
• Neuroimaging

Background:

• Rabies is a fatal neurological disease with limited treatment options once symptoms appear.
• Neuroimaging, particularly Magnetic Resonance Imaging (MRI), has shown abnormalities in the central nervous system of rabies-infected individuals.
• Previous MRI studies in humans and dogs revealed lesions in various neuroanatomical locations.

Purpose of the Study:

• To investigate the utility of advanced neuroimaging techniques in characterizing brain abnormalities and blood-brain barrier (BBB) status in rabies.
• To compare MRI findings in different forms of rabies (furious vs. paralytic) in dogs.
• To assess the potential of diffusion tensor imaging (DTI) in providing quantitative data on white matter integrity.

Main Methods:

• Magnetic Resonance Imaging (MRI) was performed on humans and dogs infected with rabies virus.
• Diffusion-weighted imaging (DWI) and diffusion tensor imaging (DTI) were utilized in a cohort of normal and rabies-infected dogs.
• Fractional anisotropy (FA) and mean diffusivity (MD) maps were generated from DTI data.

Main Results:

• MRI revealed abnormalities in various brain structures, including the brainstem, hippocampus, hypothalamus, basal ganglia, and white matter.
• The blood-brain barrier (BBB) remained intact in conscious patients/dogs but showed leakage upon progression to coma.
• DTI analysis in dogs demonstrated intact BBB, absence of vasogenic edema, and preservation of neuronal structures, except in the brainstem of paralytic rabies cases.

Conclusions:

• Neuroimaging, especially advanced techniques like DTI, offers valuable in vivo insights into central nervous system infections like rabies.
• MRI findings, including BBB status, can aid in the diagnosis and understanding of rabies pathogenesis.
• Advanced diffusion imaging techniques provide quantitative data for assessing neuronal and white matter integrity in rabies.