The role of neuroimaging in the diagnosis of the atypical parkinsonian syndromes in clinical practice

Abstract

Atypical parkinsonian disorders (APD) are a heterogenous group of neurodegenerative diseases such as: progressive supranuclear palsy (PSP), multiple system atrophy (MSA), cortico-basal degeneration (CBD) and dementia with Lewy bodies (DLB). In all of them core symptoms of parkinsonian syndrome are accompanied by many additional clinical features not typical for idiopathic Parkinson's disease (PD) like rapid progression, gaze palsy, apraxia, ataxia, early cognitive decline, dysautonomia and usually poor response to levodopa therapy. In the absence of reliably validated biomarkers the diagnosis is still challenging and mainly based on clinical criteria. However, robust data emerging from routine magnetic resonance imaging (MRI) as well as from many advanced MRI techniques such as: diffusion weighted imaging (DWI) and diffusion tensor imaging (DTI), magnetic resonance spectroscopy (MRS), voxel-based morphometry (VBM), susceptibility-weighted imaging (SWI) may help in differential diagnosis. The main aim of this review is to summarize briefly the most important and acknowledged radiological findings of conventional MRI due to its availability in standard clinical settings. Nevertheless, we present shortly other methods of structural (like TCS - transcranial sonography) and functional imaging (like SPECT - single photon emission computed tomography or PET - positron emission tomography) as well as some selected advanced MRI techniques and their potential future applications in supportive role in distinguishing APD.

An update on advances in magnetic resonance imaging of multiple system atrophy

“…1 a ‘‘Hot cross-bun sign’’ seen on an axial T2-weighted MRI in a patient with MSA-C; b putaminal hypointensity with a hyperintense “putaminal rim” sign on an axial T2-weighted MRI in a patient with MSA-P. Images adapted from [9] …”

Differentiation of neurodegenerative parkinsonian syndromes by volumetric magnetic resonance imaging analysis and support vector machine classification

“…MRI can aid in the differential diagnosis of Parkinson's disease (PD) and other neurodegenerative parkinsonian syndromes (PS) like PSP or MSA. [1][2][3] For structural cranial MRI, a variety of discriminative markers has been reported, both qualitative signs [4][5][6][7] and quantitative measures assessing the atrophy of midbrain, pons, and cerebellar peduncles. [8][9][10][11][12][13] Determination of these measures, however, is user dependent and time-consuming.…”

Positron emission tomography neuroimaging in neurodegenerative diseases: Alzheimer’s disease, Parkinson’s disease, and amyotrophic lateral sclerosis

“…PSP is clinically characterised by a vertical gaze dysfunction, extrapyramidal features and cognitive decline. The specific glucose uptake pattern in PSP is characterised by bilateral reduction of metabolism in midline frontal regions and in the brainstem [60,88,89]. The evaluated sensitivity and specificity rates in the clinical diagnosis of PSP with the 18 F-FDG-PET visual reading are 60% and 96%, respectively, and with SPM-supported reading they account for 85% and 99% [89].…”

“…The glucose uptake pattern in DLB is characterised by a predominant occipito-parietal hypometabolism with the preservation of the posterior cingulate region presenting a 'cingulate island sign' on PET scans (Tab. 2) [9,59,60]. Revised criteria for the clinical diagnosis of probable and possible DLB have included 18 F-FDG PET imaging as a supportive biomarker.…”

“…MSA is characterised by a combination of parkinsonism, autonomic dysfunction, and cerebellar ataxia. Bilateral cerebellar and putaminal hypometabolism are distinguishing PET features of the disease [60,88,89]. Cerebellar hypometabolism is present in both patients with cerebellar dysfunction (MSA--C) and those without ataxia (MSA-P) [89].…”