Putaminal hyperintensity on T1-weighted MR imaging in patients with the Parkinson variant of multiple system atrophy

A hyperintense putaminal rim, putaminal hypointensity, and putaminal atrophy on T2-weighted MR images are findings suggestive of parkinsonian-dominant multiple system atrophy (MSA-P). However, putaminal hyperintensity on T1-weighted images, which has not been discussed in previous reports, is also frequently observed in patients with MSA-P. Here, we investigated whether putaminal hyperintensity on T1-weighted images is helpful to diagnose MSA-P.

Patients with MSA-P (n = 17), Parkinson disease (PD; n = 37) and progressive supranuclear palsy (PSP; n = 11), and healthy control subjects (n = 16) were enrolled in this study. Two examiners, who were blind to the diagnoses, independently rated the putaminal hyperintensity on T1-weighted images (T1H), hyperintense putaminal rim on T2-weighted images (T2H), putaminal hypointensity on T2-weighted images (T2 L), and putaminal atrophy by using a visual analog scale, and performed a receiver operating characteristic (ROC) analysis. The area under the curve (AUC; minimum, 0.5; maximum, 1.0) was automatically calculated as a positive parameter, indicating its usefulness to differentiate between diseases.

For differentiating patients with MSA-P from healthy control subjects, AUC values were 0.983 for T1H, 0.923 for T2H, 0.726 for T2 L, and 0.967 for putaminal atrophy. Between MSA-P and PD, the respective AUC values were 0.990, 0.921, 0.739, and 0.923; and between MSA-P and PSP, the respective AUC values were 0.984, 0.923, 0.727, and 0.967.

All putaminal findings except T2 L were useful for the diagnosis of MSA-P. T1H was superior to T2H to differentiate MSA-P from other diseases.