Persistent diffusion abnormalities in the brain stem of three children with mitochondrial diseases

Area of Science:

• Neuroimaging
• Mitochondrial Diseases
• Pediatric Neurology

Background:

• Kearns-Sayre syndrome and Leigh syndrome are rare mitochondrial disorders affecting multiple organ systems, including the central nervous system.
• Brainstem involvement is a common feature in these conditions, often leading to significant neurological deficits.
• Diffusion-weighted imaging (DWI) is a sensitive MRI technique for detecting changes in water diffusion within brain tissue.

Observation:

• Serial DWI studies were performed on two children with Kearns-Sayre syndrome and one child with Leigh syndrome over extended periods (1.0–4.2 years).
• Persistent hyperintense signals were consistently observed in the pontine and mesencephalic tegmenta in all patients.
• The apparent diffusion coefficient (ADC) values in these affected brainstem regions remained consistently low throughout the observation period.

Findings:

• Low ADC values in the pontine and mesencephalic tegmenta indicate restricted water diffusion.
• This pattern suggests the presence of cytotoxic edema and/or spongiform degeneration as the underlying pathological process in these brainstem lesions.
• The persistence of these DWI findings over time highlights the chronic nature of the neuropathology in these mitochondrial disorders.

Implications:

• DWI can serve as a valuable tool for monitoring disease progression and characterizing brainstem lesions in pediatric mitochondrial disorders.
• Understanding the specific pathological basis (cytotoxic edema, spongiform degeneration) of these lesions can inform future therapeutic strategies.
• This study contributes to the neuroimaging literature on Kearns-Sayre syndrome and Leigh syndrome, emphasizing the utility of serial DWI in evaluating brainstem pathology.