MRI BRAIN Abnormalities in a Case of Spinocerebellar Ataxia (SCA)

Spinocerebellar ataxia (SCA) comprises of a group of neurodegenerative disorders characterized by progressive cerebellar ataxia (either alone or in combination with other neurological system involvement). They are currently classified into various subtypes based on the underlying genetic defect. Currently, there are about 40 subtypes of SCA, referred to as SCA 1, SCA2, ….SCA 40.

MRI brain is the preferred imaging modality in a patient suspected to have spinocerebellar ataxia.

T1W Axial MRI showing atrophy of cerebellum and pons

FLAIR Axial MRI showing atrophy of pons (red circle), linear antero-posterior hyperintensity in pons(yellow arrow) and atrophy of cerebellum (purple circle)

T2W Sagittal MRI showing atrophy of pons (predominantly anteriorly)

In the above MRI images, the following signs of SCA are seen:

1. Atrophy of pons, predominantly anterior pons
2. Atrophy of cerebellum
3. Linear antero-posterior hyperintensity in pons

In some cases, cruciform hyperintensity can be seen in pons, which is referred to as “hot cross bun” sign. This sign is also seen in multi-system atrophy.