Magnetic resonance imaging brain volumetric study as a promising structural imaging marker in patients with Parkinson’s disease

Abstract

Identifying biomarkers for neurodegenerative diseases is a challenging mission because of the difficulty of direct accessibility to the brain. Currently, the use of Magnetic Resonance Imaging (MRI) in the diagnosis of Parkinson’s disease (PD) is only to exclude secondary Parkinsonism. Our study aimed to evaluate if measuring the volume of substantia nigra (SN) by using MRI volumetry technique could be a potential imaging marker for the diagnosis of PD and to explore its association with disease severity. This case–control study included 40 patients with PD and 40 age- and sex-matched healthy controls. Patients with PD were classified into mild/moderate and severe/very severe groups according to the Hoehn and Yahr scale. Substantia nigra volumetry assessment was performed using an automated MRI volumetric pipeline. The ipsilateral and contralateral SN volumes measured in cmʒ were significantly higher in the control group compared to the mild/moderate and severe/very severe group. However, we did not find significant difference between the mild/moderate and severe/very severe groups. The ipsilateral SN cutoff volume was ≤ 0.37305 cmʒ with sensitivity and specificity of 85% and 77.5% respectively (lateralized, while the contralateral SN cutoff volume was ≤0.35914 cmʒ with sensitivity and specificity of 87.5% and 82.5% respectively. Magnetic Resonance Imaging volumetry may represent a potential MRI-based imaging biomarker for the diagnosis and follow up of PD. It might help distinguish mild PD from healthy individuals. However, its role in disease progression tracking -although noticed in our current study, yet it cannot be confidentially established and still requires a longitudinal validation and larger sample size.