Proton magnetic resonance spectroscopy in corticobasal degeneration and progressive supranuclear palsy

Background:   Corticobasal degeneration (CBD) and progressive supranuclear palsy (PSP) each have distinctive clinical features, but diagnosis is often uncertain. Our purpose was to evaluate whether localized, single-voxel proton magnetic resonance spectroscopy (¹H-MRS) could distinguish between typical CBD and PSP patients.
Methods:   The study included 10 patients with CBD, nine with PSP and eight age-matched normal healthy subjects. A single-voxel method of 8 cm³ (2 × 2 × 2 cm) was used for ¹H-MRS. The volume of interest was selected at the frontoparietal cortex and the lentiform nucleus.
Results:   Patients with CBD had significantly reduced ratios of N-acetylaspartate to choline-containing compounds (NAA/Cho), N-acetylaspartate to creatine and phosphocreatine (NAA/Cr) in the frontoparietal cortex and lentiform nucleus compared with the normal subjects. Patients with PSP had significantly reduced NAA/Cho and NAA/Cr ratios in the lentiform nucleus, but not in the frontoparietal cortex compared with normal subjects. There was a significant difference in the NAA/Cho in the frontoparietal lobe between CBD and PSP patients.
Conclusion:   ¹H-MRS may indicate different regional patterns of neuronal involvement in CBD and PSP. We suggest that this could be helpful in the differentiation and diagnostic evaluation of CBD and PSP patients.