MR imaging in progressive supranuclear palsy and Shy-Drager syndrome.

Previous reports have suggested that putaminal hypointensity in T2-weighted images at high field strength (1.5 T) magnetic resonance (MR) is a common finding in atypical parkinsonian syndromes, including progressive supranuclear palsy (PSP) and Shy-Drager syndrome (SDS). We have reviewed nine patients with PSP and five with SDS, selected on strict clinical criteria. Only in one PSP patient was abnormal signal intensity (putaminal hypointensity more marked than pallidal) found. However, hypointensity was often marked in the substantia nigra and occasionally in the superior colliculi. Focal midbrain atrophy, involving particularly the upper part of the quadrigeminal plate, was obvious in five cases. In general there was no uniformity of findings and MR appears unable to consistently support the clinical diagnosis of PSP. In SDS patients the findings were more uniform, with hypointensity in the putamen, superior or equal to that of the pallidum. At low or intermediate field strength, there was absence of magnetic susceptibility effect in the putamen, which appeared hyperintense. This was probably because of increased water content due to gliosis and/or cell loss. The constancy of the MR findings in our SDS series suggests a supportive diagnostic role for MR imaging.