Differentiating progressive supranuclear palsy from Parkinson's disease by MRI-based dynamic cerebrospinal fluid flow

The purpose of this study was to clarify the difference between PSP and PD from the viewpoint of dynamic cerebrospinal fluid (CSF) flow focusing on the midbrain aqueduct.

Thirty-three PD patients (mean age 69.2±7.9) and 35 PSP patients (mean age 70.5±6.6) were included in this study. CSF flow was calculated by 15 images in an equidistant magnetic resonance imaging (MRI) sequence that was taken throughout a cardiac cycle.

Absolute values of the velocity (time points of 2-6 and 12-15, *p<0.05), and the width of the CSF velocity (Vheight) (PSP, 5.1±2.3cm/s; PD, 6.0±1.6cm/s, p<0.05) effectively discriminated PSP from PD patients. On the other hand, conventional MRI measurements discriminated well the midbrain aqueduct area (Area) (PSP, 7.7±2.6mm(2); PD, 5.4±1.8mm(2), p<0.01). Two cutoff value lines (Vheight: 4.75, Area: 5.77) of the ROC curve analysis established two areas for discriminating PSP from PD.

In the present dynamic CSF flow study, it was newly found that mean velocity of each time point and Vheight showed a more significant decline in PSP than in PD patients, providing a sensitive biomarker for differentiating them. The combination of Vheight and Area could further discriminate PSP from PD patients.