Table 4.

Criteria for the differentiation of progressive supranuclear palsy, MSA-P, and MSA-C on routine MRI in a patient with atypical parkinsonism

Progressive supranuclear palsyMSA-PMSA-C
* On 0.5-T scan.
MSA-P = multiple system atrophy with predominant parkinsonism; MSA-C = MSA with predominant cerebellar features.
Midbrain diameter on axial scans < 17 mmHyperintense putaminal rimDilatation of the fourth ventricle
Signal increase in the midbrainPutaminal hyperintensity*Atrophy of the medulla, dentate nucleus, middle cerebellar peduncles, pons, inferior olives
Dilatation of the third ventricleAtrophy of the dentate nucleusSignal increase in the cerebellum, middle cerebellar peduncles, pons (hot-cross bun sign), inferior olives
Frontal or temporal lobe atrophyDilatation of the fourth ventricle
Signal increase in the globus pallidus*Signal increase in the cerebellum, middle cerebellar peduncles, pons (hot-cross bun sign)
Atrophy or signal increase of the red nucleus