Spectrum of magnetic resonance abnormalities in leigh syndrome with emphasis on correlation of diffusion-weighted imaging findings with clinical presentation.

Background: Leigh syndrome (LS) is a progressive neurodegenerative disorder of infancy/early childhood secondary to mitochondrial dysfunction. Imaging plays a pivotal role in the diagnosis of LS with certain typical magnetic resonance imaging (MRI) findings considered as a part of diagnostic criteria. We appraised various MRI findings on conventional MRI sequences and also assessed potential correlation between diffusion abnormalities and patient's clinical presentation. Aims: Our aim was to describe various patterns of central nervous system involvement in LS and to assess the correlation of diffusion-weighted imaging abnormalities with clinical presentation. Settings and Design: The design of the study was retrospective comprising 8 children with LS who had MRI between years 2014 and 2019. Subjects and Methods: Eight children between the age group of 4 months 8 years with LS based on clinical presentation, elevated lactate levels in CSF/Blood, and typical MRI findings were included in the study. Results and Conclusions: Brainstem was involved all (100%) patients while basal ganglia was affected in 5 (62.5%) children. Cerebral white matter involvement was present in 3 (37.5%) children, cerebellar in 2 (25%) children while spinal, corpus callosum, and thalamic involvement were observed in one (12.5%) patient each. Diffusion restriction was observed in 6 children, all of them presented with altered sensorium. Conventional MRI serves as an excellent tool for the diagnosis of LS in children with clinical suspicion. Acute encephalopathy frequently presents with diffusion restriction corresponding to active lesions. Hence, diffusion restriction on MRI predicts the activity of lesions in patients with LS.