On T2-weighted MRI of the pons, a cruciform area of hyperintensity resembling a hot cross bun is seen in the basis pontis. This finding is most classically associated with:

• A Progressive supranuclear palsy
• B Multiple system atrophy, cerebellar type ✓
• C Central pontine myelinolysis
• D Pontine infarction from basilar occlusion

Explanation

The hot cross bun sign reflects selective degeneration of transverse pontocerebellar fibres and median raphe neurons with relative sparing of the corticospinal tracts, which remain dark and form the cross arms. It is described classically in multiple system atrophy cerebellar type. Central pontine myelinolysis gives a central triangular or bat wing hyperintensity that spares the periphery, not a cruciform pattern.

Reference: Grainger and Allison Diagnostic Radiology, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.