Canavan disease: diffusion magnetic resonance imaging findings

Area of Science:

• Neurology
• Radiology
• Biophysics

Background:

• Canavan disease is a rare, fatal genetic neurodegenerative disorder.
• It affects myelin development, leading to severe neurological impairment.
• Histopathology shows edematous, gelatinous brain tissue with vacuolization.

Observation:

• A 15-month-old boy with Canavan disease presented with characteristic diffusion magnetic resonance imaging (MRI) findings.
• Restricted diffusion (high signal on b=1,000 mm2/s images, low apparent diffusion coefficient [ADC] values) was observed in multiple brain regions.
• Affected areas included peripheral white matter, globi pallidi, thalami, brainstem, dorsal pons, and dentate nuclei.

Findings:

• ADC values in affected regions ranged from 0.42 to 0.56 x 10(-3) mm2/s.
• Normal ADC values in unaffected deep frontal white matter were higher (0.68-0.92 x 10(-3) mm2/s).
• The observed restricted diffusion pattern is consistent with altered water molecule states.

Implications:

• The findings suggest that the restricted diffusion in Canavan disease may result from a gel-like state of water molecules in affected brain tissue.
• This contrasts with the typical sol state observed in healthy brain tissue.
• Diffusion MRI may offer insights into the biophysical properties of brain tissue in Canavan disease and other white matter disorders.