Significance of MRI in Diagnosis and Differential Diagnosis of Parkinson’s Disease

Abstract

The differential diagnosis of parkinsonian syndromes is considered one of the most challenging in neurology, even for movement disorder specialists. Despite published consensus operational criteria for the diagnosis of Parkinson’s disease (PD) and the various atypical parkinsonian disorders (APDs) such as progressive supranuclear palsy, multiple system atrophy, and corticobasal syndrome, the clinical separation of APDs from PD carries a high rate of misdiagnosis. However, an early differentiation between APD and PD, each characterized by a largely different natural history, is crucial for determining the prognosis and choosing a treatment strategy. Despite limitations, the different modern magnetic resonance (MR) techniques have undoubtedly added to the differential diagnosis of neurodegenerative parkinsonism. Conventional MRI with visual assessment of T₂- and T₁-weighted imaging as well as various advanced MRI techniques offer objective measures and may therefore be useful tools in the diagnostic workup of PD and APDs. In clinical practice, conventional MRI is a well-established method for the exclusion of symptomatic parkinsonism due to other pathologies such as tumors, cerebral ischemia or inflammatory diseases. Furthermore, over the past two decades, advances in MR techniques have enabled to quantitatively illustrate abnormalities in the basal ganglia and infratentorial structures in APDs by methods such as magnetic resonance volumetry, diffusion-weighted imaging, magnetization transfer imaging and proton magnetic resonance spectroscopy. This article aims to review research findings on the value of MRI techniques in the differential diagnosis of neurodegenerative parkinsonian disorders.

Frontal Corpus Callosum Alterations in Progressive Supranuclear Palsy but Not in Parkinson's Disease

“…These findings expand the previously known results of conventional and diffusion-weighted MRI [6,34,35,36,37]. In a recent DTI study in PSP, metrics of the CC and superior cerebellar peduncles were found to be the best predictors of global disease severity scale scores [38]; here, an alternative postprocessing cascade was used, estimating the diffusion tensor using the DTIfit toolbox (http://www.fmrib.ox.ac.uk/fsl/).…”

“…a ‘classical' presentation classified as Richardson's syndrome (PSP-RS) and a subtype characterized by a more Parkinson's disease (PD)-like presentation in the early disease course classified as PSP-parkinsonism (PSP-P) [4]. In the diagnostic workup, magnetic resonance imaging (MRI) signs of PSP include prominent midbrain and pons atrophy, which have been combined in the conventional MR parkinsonism index [5,6]. Volumetric/morphometric MRI studies have shown frontal atrophy in PSP [7,8] and have demonstrated tissue loss in fronto-/mesiotemporal cortices and prefrontal regions in addition to the central midbrain and basal ganglia [9,10].…”

Diffusion Tensor Imaging in Idiopathic Parkinson's Disease and Multisystem Atrophy (Parkinsonian Type)

“…Mahlknecht et al [22] offer an updated overview of MRI-based methods for the differentiation of PD and AP. Characteristic differences of regional ADC and FA values between PD and MSAp patients as well as compared to healthy controls have been previously described.…”

Susceptibility-Weighted Imaging Improves the Diagnostic Accuracy of 3T Brain MRI in the Work-Up of Parkinsonism

“…First, abnormalities that have been validated for the evaluation of parkinsonian syndromes were scored. [3][4][5]25 Second, selected abnormalities were grouped in a score typical for a given disease. Atrophy and T2 hypointensity changes of the putamen, pontine atrophy, hot cross bun sign, cerebellar atrophy, and T2 hyperintense signal changes of the middle cerebellar peduncle were combined in the "MSA" score.…”

“…[3][4][5] New MR imaging techniques have become available for clinical practice in recent years, including susceptibility-weighted imaging. SWI is sensitive to magnetic susceptibility differences in tissues such as blood, calcification, and iron deposition.…”