Widespread diffusion changes differentiate Parkinson's disease and progressive supranuclear palsy

Abstract

BackgroundParkinson's disease (PD) and progressive supranuclear palsy – Richardson's syndrome (PSP-RS) are often represented by similar clinical symptoms, which may challenge diagnostic accuracy. The objective of this study was to investigate and compare regional cerebral diffusion properties in PD and PSP-RS subjects and evaluate the use of these metrics for an automatic classification framework.Material and methodsDiffusion-tensor MRI datasets from 52 PD and 21 PSP-RS subjects were employed for this study. Using an atlas-based approach, regional median values of mean diffusivity (MD), fractional anisotropy (FA), radial diffusivity (RD), and axial diffusivity (AD) were measured and employed for feature selection using RELIEFF and subsequent classification using a support vector machine.ResultsAccording to RELIEFF, the top 17 diffusion values consisting of deep gray matter structures, the brainstem, and frontal cortex were found to be especially informative for an automatic classification. A MANCOVA analysis performed on these diffusion values as dependent variables revealed that PSP-RS and PD subjects differ significantly (p < .001). Generally, PSP-RS subjects exhibit reduced FA, and increased MD, RD, and AD values in nearly all brain structures analyzed compared to PD subjects. The leave-one-out cross-validation of the support vector machine classifier revealed that the classifier can differentiate PD and PSP-RS subjects with an accuracy of 87.7%. More precisely, six PD subjects were wrongly classified as PSP-RS and three PSP-RS subjects were wrongly classified as PD.ConclusionThe results of this study demonstrate that PSP-RS subjects exhibit widespread and more severe diffusion alterations compared to PD patients, which appears valuable for an automatic computer-aided diagnosis approach.

Neuroimaging Advances in Parkinson's Disease and Atypical Parkinsonian Syndromes

“…PSP patients with vertical supranuclear gaze palsy exhibited lower FA values in the midbrain vs. those with slowness of vertical saccades, highlighting the role of midbrain atrophy in vertical ocular dysfunction (146). PSP-RS patients also showed more severe and widespread diffusion abnormalities vs. PD, which reflects greater microstructural damage as consistent with greater overall brain atrophy often found in PSP-RS than in PD cases (147). Moreover, damage to the SCPs may be detected in both PSP-RS and PSP-parkinsonism subtypes (130,145).…”

“…When the two subtypes were directly compared, PSP-RS patients showed decreased FA and increased D in the left SCP vs. PSP-parkinsonism patients (145). Computer-aided diagnosis of PSP and its subtypes may be possible using diffusion-weighted/DTI measures (145,147).…”

Modern Brainstem MRI Techniques for the Diagnosis of Parkinson's Disease and Parkinsonisms

“…The highest AUC for PD vs. PSP was in the LC (0.94). In the same vein, Talai et al (65) found AUCs of 0.95 and 0.97 based on DTI metrics in the midbrain for PD vs. PSP. DTI abnormalities in the midbrain of patients with PSP reflect microstructural changes that precede the macrostructural changes revealed by midbrain atrophy (65).…”

Neuroimaging in Vascular Parkinsonism

“…Lower FA and higher MD values suggest increasing disruption of white matter tracts and water content, respectively. FA in substantia nigra was shown to be reduced in IPD compared with healthy control, while FA was reduced and MD was increased in pons, cerebellum, MCP and putamen in MSA when compared with IPD and healthy controls, and FA was reduced and MD was increased in frontal white matter, midbrain, basal ganglion and SCP in PSP when compared with IPD [74–76]. DTI is an emerging research tool to differentiate IPD and other neurodegenerative parkinsonism.…”