Investigation of the significance of quantitative MRI parameters in differentiating PSP from MSA patients.

Abstract

Objective: To investigate the utility of quantitative MRI parkinsonism indices in discriminating between progressive supranuclear palsy (PSP) and multiple system atrophy (MSA) patients.

Methods: In our study including PSP and MSA patients, we calculated the radiological measures including superior cerebellar peduncle width, middle cerebellar peduncle width, third ventricle width, 3rdV/bifrontal width, pons/mesencephalon (P/M) ratio, P/M ratio 2.0, magnetic resonance parkinsonism index (MRPI), and MRPI 2.0 values. We also constituted a PMS scale to increase the discrimination power.

Results: Comparisons between PSP and MSA patients revealed significant differences in the mesencephalon area, third ventricle width, 3rdV/bifrontal width, P/M ratio, P/M ratio 2.0, MRPI, and MRPI 2.0 values (p < 0.01 for all). The AUC values were acceptable for the third ventricle width, the 3rdV/bifrontal width ratio, the P/M ratio, the P/M 2 ratio, the MRPI and the MRPI-2. In distinguishing PSP, 0 points on the PMS scale had a negative predictive value (NPV) of 91%, whereas 3 points had a positive predictive value (PPV) of 85.7%.

Conclusion: None of the MRI parameters reached a good diagnostic AUC in distinguishing PSP from MSA. However, the PMS scale we propose in this study may provide high PPVs and NPVs for differential diagnosis during desk-based evaluation.