Magnetic resonance imaging for the diagnosis of Parkinson's disease

Abstract

The differential diagnosis of parkinsonian syndromes is considered one of the most challenging in neurology and error rates in the clinical diagnosis can be high even at specialized centres. Despite several limitations, magnetic resonance imaging (MRI) has undoubtedly enhanced the diagnostic accuracy in the differential diagnosis of neurodegenerative parkinsonism over the last three decades. This review aims to summarize research findings regarding the value of the different MRI techniques, including advanced sequences at high- and ultra-high-field MRI and modern image analysis algorithms, in the diagnostic work-up of Parkinson's disease. This includes not only the exclusion of alternative diagnoses for Parkinson's disease such as symptomatic parkinsonism and atypical parkinsonism, but also the diagnosis of early, new onset, and even prodromal Parkinson's disease.

Keywords: Atypical parkinsonism; MRT; Multiple system atrophy; Parkinson's disease; Progressive supranuclear palsy.

Fig. 1

Secondary causes of parkinsonism. This figure shows examples of secondary causes of parkinsonism. a Normal pressure hydrocephalus with disproportionally dilated lateral ventricles and periventricular hyperintensities suggesting transependymal flow on an axial T2 image. b Brainstem tumor mass (glioma) on an axial T2 image. c Severe leucencephalopathy with multiple  white matter lesions on an axial T2 image in a patient with vascular parkinsonism. d Central nervous system toxoplasmosis with contrast enhanced lesions (also in the basal ganglia) on a contrast-enhanced axial T1 image in a HIV-positive patient. e Hypoxic basal ganglia lesions (putaminal signal increases on an axial T2 image) after carbon monoxide poisoning. f Olfactory meningioma as an example for a frontal space-occupying lesion on an axial T2 image. Modified from Neuroimaging of Movement Disorders, Structural MRI in Idiopathic Parkinson Disease and Parkinsonism, Volume 44 of the series Current Clinical Neurology, 2013, pp 105-128, Mueller C et al., with permission of Springer

Fig. 2

This figure illustrates a selection of MRI features that were shown to be typical findings in atypical parkinsonian disorders. a The hot cruss bun sign on an axial T2 image in a patient with multiple system atrophy (MSA). b Putaminal atrophy with the putaminal hyperintense rim (arrow) on an axial T2 image in a patient with MSA. c Putaminal atrophy with putaminal hypointensity on an axial T2 image in a patient with MSA. d Atrophy of the pons and the cerebellum on a midsagittal T1 image as a common finding in MSA reflecting olivopontocerebellar atrophy. e The hummingbird sign (atrophy of the rostral midbrain tegmentum) on a midsagittal T1 image and f the morning glory flower sign (concavity of the lateral margin of the tegmentum) on an axial T2 image reflecting midbrain atrophy in progressive supranuclear palsy patients. Modified from Neuroimaging of Movement Disorders, Structural MRI in Idiopathic Parkinson Disease and Parkinsonism, Volume 44 of the series Current Clinical Neurology, 2013, pp 105-128, Mueller C et al., with permission of Springer

Fig. 3

Pragmatic approach to reading a MRI in a patient presenting with early parkinsonism. 1 With higher field MRI using neuromelanin-sensitive MRI or iron-sensitive sequences (lack of DNH). 2 Such as radiotracer-imaging studies (e.g. presynaptic dopaminergic imaging such as dopamine-transporter-SPECT or myocardial postganglionic sympathetic imaging such as metaiodobenzylguanidine-scintigraphy). 3 Refer to qualitative (such as atrophy or signal changes) or quantitative changes (using quantitative assessment of regional cerebral atrophy or quantitative structural MR-based techniques such as diffusion imaging or iron-sensitive sequences). BG basal ganglia, SN substantia nigra, PD Parkinson’s disease, MSA multiple system atrophy, PSP progressive supranuclear palsy, SCP superior cerebellar peduncle, MCP middle cerebellar peduncle