Middle cerebellar peduncles and Pontine T2 hypointensities in ARSACS

Magnetic resonance imaging (MRI) of autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) cases in Quebec and Europe was reported to show linear hypointensities in T2-weighted and Fluid Attenuated Inversion Recovery (FLAIR) images of the pons. We attempted to clarify the characteristics of the brain MRI findings in ARSACS cases.

Eight Japanese early-onset ataxia patients with ARSACS confirmed molecularly were investigated. We performed neurological examination, SACS gene analysis, and MRI in the patients.

Hypointensity lesions in the middle cerebellar peduncles in addition to the pons were observed in T2-weighted and FLAIR images in all eight cases. Although superior cerebellar atrophy was seen in all cases, this MRI finding might not be specific for ARSACS. Upper cervical cord and medulla oblongata atrophy was not observed in 3 of the 7 patients examined.

Not only pontine but also middle cerebellar peduncle hypointensity lesions observed in T2-weighted and FLAIR images could be specific findings for ARSACS even in cases with variable clinical phenotypes.