Differentiation of atypical parkinsonian syndromes with routine MRI

Objective: To evaluate the use of routine MRI in differentiating between patients with progressive supranuclear palsy (PSP), multiple system atrophy (MSA), corticobasal degeneration (CBD) and control subjects. Methods: Two neuroradiologists rated blindly and independently axial TX-weighted and proton density MR images of 54 patients with MSA, 35 patients with PSP, 5 patients with CBD, and 44 control subjects. Results: More than 70% of patients with PSP and more than 80% of patients with cerebellar predominant MSA could be classified correctly with 0.5-T or 1.5-T scans, and no patient in these groups was misclassified. In the remaining patients an unequivocal differentiation could not be made. However, only approximately 50% of patients with parkinsonism-predominant MSA could be classified correctly, and 19% of them (all of whom had had 0.5-T scans) were misclassified. Conclusions: Characteristic findings on routine MRI, either 1.5 T or 0.5 T, can contribute to the identification of MSA and PSP. However, in a minority of patients no unequivocal diagnosis can be made using MRI findings alone.