Progressive Supranuclear Palsy: New Brain Stem Measurement and its Clinical Correlations

Objective: To detect the value of mid-sagittal MRI measurements of the midbrain and pons in the diagnosis of Progressive Supranuclear Palsy (PSP) and to differentiate it from mimics [Parkinson Disease (PD) and Multiple-System Atrophy of the Parkinson Type (MSA-P)], and to what extend these radiological measurements correlate with the clinical aspects of PSP. Methods: MRI of 13 patients with PSP, 25 patients with PD, and 10 patients with MSA-P, as well as 20 age-matched controls were prospectively studied. The areas of the midbrain tegmentum and the pons were measured on mid-sagittal MRI using the display tools. The ratio of the area of the midbrain to the area of the pons was also evaluated in all subjects. Patients were also evaluated clinically using Hoehn and Yahr Scale, UPDRS and MMSE scale in addition to full general, neurological assessment and routine laboratory investigations. Results: The average midbrain area of the patients with PSP (57 mm^2 ) was significantly smaller than that of the patients with PD (101 mm^2 ) and MSA-P (97.9 mm^2 ) and that of the age-matched control group (116.9 mm^2). There was no overlap between patients with PSP and patients with PD or normal control subjects regarding midbrain area values. However, patients with MSA-P showed some overlap of the values of individual areas with values from patients with PSP. The ratio of the area of the midbrain to the area of pons inpatients with PSP (0.123) was significantly smaller than that in those with PD (0.207) and MSA-P (0.265) and in normal control subjects (0.235). Also, use of the ratios allowed differentiation between PSP groups and the MSA-P group. Good significant correlation was observed between various radiological measurements studied and disease duration, staging and severity. Conclusion: The mid-sagittal MRI measurements of the midbrain area can differentiate between the PSP from PD, MSA-P and normal aging and these radiological measurements correlated well with the clinical aspects of the syndrome of PSP.