Prominent atrophy of the midbrain, and superior colliculus. The basal ganglia are normal. No changes in the putamen that are usually associated with MSA-P. No changes in the pons to suggest MSA-C. No abnormal iron accumulation noted.
Volume loss also involves the left frontal lobe and insula. Dilated lateral, 3rd and 4th ventricles with prominent bilateral Sylvian fissures. Small subependymal cyst noted along the right frontal horn. No definite transependymal oedema demonstrated. The aqueduct is patent with prominent CSF flow void. Quantitative measurements of flow are within normal range (not shown). No downward bowing of the floor of the third ventricle.
No abnormal diffusion restriction.
Midbrain to pons ratio: 0.15 MRPI: 28.25
Conclusion:
Findings are most in keeping with PSP.