Multiple system atrophy

• MRI has high specificity for differentiating MSA from Parkinson disease
  • T2 hyperintensities in the pontocerebellar tracts:
    • Pons - hot cross bun sign
    • Middle cerebellar peduncles - middle cerebellar peduncle sign
    • Inferior cerebellar peduncles - inferior cerebellar peduncle sign
    • Cerebellum
  • Abnormal putaminal signal
    • reduced signal on T2*, GRE or SWI sequences relative to the globus pallidus and red nucleus
    • abnormally high T2 linear rim surrounding the putamen (putaminal rim sign) seen at 1.5 T (this is normal at 3 T)
  • Disproportionate atrophy
    • Putamen
    • Pons
    • Middle cerebellar peduncle
    • Cerebellum