New MRI diagnostic methods in Parkinson's disease: evaluating nigral degeneration

Abstract

Research Center of Neurology, Moscow, Russia Parkinson's disease (PD) is a progressive neurodegenerative disorder with a characteristic pathological hallmark of loss of the dopaminergic neurons in the compact part of the substantia nigra in the midbrain. Despite the significant progress made in learning about this disease, early diagnosis continues to be a complex clinical issue. Currently, many studies are focused on finding and implementing meaningful markers which are valid for the early PD diagnosis. One of the most promising areas in that field is investigation of specific changes in the substantia nigra, found when examining the nigrosomes (specific clusters of the dopaminergic neurons) and neuromelanin, using high-field magnetic resonance imaging (MRI). This article presents the current understanding of the structural and functional organization of the substantia nigra, and examines in detail the new informative MRI-markers of neurodegeneration in PD: the loss of dorsolateral nigral hyperintensity (disappearance of the nigrosome-1) and a reduction in the intensity/area of the magnetic resonance signal from the substantia nigra when imaging the neuromelanin. We present our own experience of using the abovementioned technologies to diagnose PD, by analysing susceptibility-weighted images and images taken in neuromelanin-sensitive MRI mode.

Keywords

• parkinson's disease
• diagnosis
• neuroimaging
• mri
• substantia nigra
• nigrosome
• neuromelanin