Quantifying cerebellar atrophy in multiple system atrophy of the cerebellar type (MSA-C) using three-dimensional gyrification index analysis

Diffusion Tensor Magnetic Resonance Imaging for Differentiating Multiple System Atrophy Cerebellar Type and Spinocerebellar Ataxia Type 3

Multiple system atrophy cerebellar type (MSA-C) and spinocerebellar ataxia type 3 (SCA3) demonstrate similar manifestations, including ataxia, pyramidal and extrapyramidal signs, as well as atrophy and signal intensity changes in the cerebellum and brainstem. MSA-C and SCA3 cannot be clinically differentiated through T1-weighted magnetic resonance imaging (MRI) alone; therefore, clinical consensus criteria and genetic testing are also required. Here, we used diffusion tensor imaging (DTI) to measure water molecular diffusion of white matter and investigate the difference between MSA-C and SCA3. Four measurements were calculated from DTI images, including fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity (RD), and mean diffusivity (MD). Fifteen patients with MSA-C, 15 patients with SCA3, and 30 healthy individuals participated in this study. Both patient groups demonstrated a significantly decreased FA but a significantly increased AD, RD, and MD in the cerebello-ponto-cerebral tracts. Moreover, patients with SCA3 demonstrated a significant decrease in FA but more significant increases in AD, RD, and MD in the cerebello-cerebral tracts than patients with MSAC. Our results may suggest that FA and MD can be effectively used for differentiating SCA3 and MSA-C, both of which are cerebellar ataxias and have many common atrophied regions in the cerebral and cerebellar cortex.

Cerebellar atrophy and its contribution to motor and cognitive performance in multiple system atrophy

Objective

Neuroanatomical differences in the cerebellum are among the most consistent findings in multiple system atrophy (MSA) patients. This study performed a detailed cerebellar morphology in MSA patients and its two subtypes: MSA-P (parkinson's symptoms predominate) and MSA-C (cerebellar symptoms predominant), and their relations to profiles of motor and cognitive deficits.

Materials and methods

Structure MRI data were acquired from 63 healthy controls and 61 MSA patients; voxel-based morphometry and the Spatially Unbiased Infratentorial Toolbox cerebellar atlas were performed to identify the cerebellar gray volume changes in MSA and its subtypes. Further, the gray matter changes were correlated with the clinical motor/cognitive scores.

Results

Patients with MSA exhibited widespread loss of cerebellar volume bilaterally, relative to healthy controls. In those with MSA-C, gray matter loss was detected from anterior (bilateral lobule IV-V) to posterior (bilateral crus I/II, bilateral lobule IX, left lobule VIII) cerebellar lobes. Lower anterior cerebellar volume negatively correlated with disease duration and motor performance, whereas posterior lobe integrity positively correlated with cognitive assessment. In patients with MSA-P, atrophy of anterior lobe (bilateral lobules IV-V) and posterior lobe in part (left lobule VI, bilateral IX) was evident; and in left cerebellar lobule IX, gray matter loss negatively correlated with motor scores. Direct comparison of MSA-P and MSA-C group outcomes showed divergence in right cerebellar crus II only.

Conclusions

Our data suggest that volumetric abnormalities of cerebellum contribute substantially to motor and cognitive performance in patients with MSA. In patients with MSA-P and MSA-C, affected regions of cerebellum differed.

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Cerebellum atrophy contributed substantially to motor and cognitive behavior in MSA.

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Lower cerebellum IV-V volume was correlated with MSA-C disease duration and severity

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Cerebellum atrophy in one side may imply symptoms onset on contralateral

MRI supervised and unsupervised classification of Parkinson's disease and multiple system atrophy

BACKGROUND

Multimodal MRI approach is based on a combination of MRI parameters sensitive to different tissue characteristics (eg, volume atrophy, iron deposition, and microstructural damage). The main objective of the present study was to use a multimodal MRI approach to identify brain differences that could discriminate between matched groups of patients with multiple system atrophy, Parkinson's disease, and healthy controls. We assessed the 2 different MSA variants, namely, MSA-P, with predominant parkinsonism, and MSA-C, with more prominent cerebellar symptoms.

METHODS

Twenty-six PD patients, 29 MSA patients (16 MSA-P, 13 MSA-C), and 26 controls underwent 3-T MRI comprising T2*-weighted, T1-weighted, and diffusion tensor imaging scans. Using whole-brain voxel-based MRI, we combined gray-matter density, T2* relaxation rates, and diffusion tensor imaging scalars to compare and discriminate PD, MSA-P, MSA-C, and healthy controls.

RESULTS

Our main results showed that this approach reveals multiparametric modifications within the cerebellum and putamen in both MSA-C and MSA-P patients, compared with PD patients. Furthermore, our findings revealed that specific single multimodal MRI markers were sufficient to discriminate MSA-P and MSA-C patients from PD patients. Moreover, the unsupervised analysis based on multimodal MRI data could regroup individuals according to their clinical diagnosis, in most cases.

CONCLUSIONS

This study demonstrates that multimodal MRI is able to discriminate patients with PD from those with MSA with high accuracy. The combination of different MR biomarkers could be a great tool in early stage of disease to help diagnosis. © 2018 International Parkinson and Movement Disorder Society.

The involvement of supratentorial white matter in multiple system atrophy: a diffusion tensor imaging tractography study

It has been assumed that cognitive disorder and visual-spatial disturbance in multiple system atrophy of the predominantly cerebellar type (MSA-C) are attributable to degradation of cerebellar function. The purpose of this study was to use diffusion tensor imaging (DTI) tractography to determine if patients with MSA-C characterized in part by visual-spatial disorders and cognitive disorders have changes of the structural connectivity network of nerve fibers, and to further describe the structural connectivity network. The study included 20 patients with MSA-C and 30 age- and sex-matched healthy controls. A 1.5T magnetic resonance imaging (MRI) scanner was used to obtain images for DTI tractography. Image preprocessing was done by large deformation diffeomorphic metric mapping. Whole-brain connectivity analysis was carried out. The patients had decreased numbers of long association fibers connecting the right parietal lobe to the frontal lobe. The commissural fibers and short association fibers connecting the bilateral frontal and occipital lobes and the number of short association fibers at the bilateral frontal and occipital region were also decreased significantly. The patients had a significant decrease in fiber density in the cerebellum compared to the healthy subjects. Our results provide DTI evidence suggesting that frontal and occipital white matter is involved in patients with MSA-C. This finding may correlate with their clinical symptoms such as cognitive disturbance as well as visual-spatial impairment. Therefore, cognitive disturbance and visual-spatial deficits in MSA-C might not be due to cerebellar lesions only as is widely believed but also involve cerebral lesions.

Progression of alpha-synuclein pathology in multiple system atrophy of the cerebellar type

AIMS

The aim of this study was to identify early foci of α-synuclein (α-syn pathology) accumulation, subsequent progression and neurodegeneration in multiple system atrophy of the cerebellar type (MSA-C).

METHODS

We analysed 70-μm-thick sections of 10 cases with MSA-C and 24 normal controls.

RESULTS

MSA-C cases with the lowest burden of pathology showed α-syn glial cytoplasmic inclusions (GCIs) in the cerebellum as well as in medullary and pontine cerebellar projections. Cerebellar pathology was highly selective and severely involved subcortical white matter, whereas deep white matter and granular layer were only mildly affected and the molecular layer was spared. Loss of Purkinje cells increased with disease duration and was associated with neuronal and axonal abnormalities. Neocortex, basal ganglia and spinal cord became consecutively involved with the increasing burden of α-syn pathology, followed by hippocampus, amygdala, and, finally, the visual cortex. GCIs were associated with myelinated axons, and the severity of GCIs correlated with demyelination.

CONCLUSIONS

Our findings indicate that cerebellar subcortical white matter and cerebellar brainstem projections are likely the earliest foci of α-syn pathology in MSA-C, followed by involvement of more widespread regions of the central nervous system and neurodegeneration with disease progression.

Change in the cortical complexity of spinocerebellar ataxia type 3 appears earlier than clinical symptoms

Patients with spinocerebellar ataxia type 3 (SCA3) have exhibited cerebral cortical involvement and various mental deficits in previous studies. Clinically, conventional measurements, such as the Mini-Mental State Examination (MMSE) and electroencephalography (EEG), are insensitive to cerebral cortical involvement and mental deficits associated with SCA3, particularly at the early stage of the disease. We applied a three-dimensional fractal dimension (3D-FD) method, which can be used to quantify the shape complexity of cortical folding, in assessing cortical degeneration. We evaluated 48 genetically confirmed SCA3 patients by employing clinical scales and magnetic resonance imaging and using 50 healthy participants as a control group. According to the Scale for the Assessment and Rating of Ataxia (SARA), the SCA3 patients were diagnosed with cortical dysfunction in the cerebellar cortex; however, no significant difference in the cerebral cortex was observed according to the patients’ MMSE ratings. Using the 3D-FD method, we determined that cortical involvement was more extensive than involvement of traditional olivopontocerebellar regions and the corticocerebellar system. Moreover, the significant correlation between decreased 3D-FD values and disease duration may indicate atrophy of the cerebellar cortex and cerebral cortex in SCA3 patients. The change of the cerebral complexity in the SCA3 patients can be detected throughout the disease duration, especially it becomes substantial at the late stage of the disease. Furthermore, we determined that atrophy of the cerebral cortex may occur earlier than changes in MMSE scores and EEG signals.

Volumetric changes in cerebellar regions in adolescent idiopathic scoliosis compared with healthy controls

BACKGROUND CONTEXT

Adolescent idiopathic scoliosis (AIS) is a three-dimensional spinal deformation that affects adolescents, especially girls. The etiopathogenesis of this disease remains uncertain, and studies have been carried out to understand its cause and related organs. Previous studies suggest that AIS is probably related to the cerebellum dysfunction, which could also be related to the abnormality in morphology of the cerebellum.

PURPOSE

The purpose of the study is to investigate the relationship between AIS and the volume and morphology of cerebellum.

STUDY DESIGN/SETTING

The study design of the cerebellum segmentation and volume quantification involved the following four steps: whole-brain normalization, cerebellum isolation, mapping with the statistical cerebellum template, and cerebellum regional volume correction.

PATIENT SAMPLE

In particular, high-resolution T1-weighted magnetic resonance images of 50 AIS patients with the right-thoracic curves (ie, Cobb angle ≥20°) and 40 age-matched normal controls were acquired. The exclusion criteria included history of head injury, back injury, severe headache, weakness or numbness in any limbs, urinary incontinence, nocturnal enuresis, and any space-occupying lesion found on magnetic resonance (MR) images.

OUTCOME MEASURES

The AIS subjects were all with moderate-to-severe curves (ie, Cobb angle ≥20°) (9 moderate and 41 severe; mean Cobb angle 48.7°, range 20°-90°).

METHODS

The cerebellum was parcellated to 28 regions by mapping with a well-recognized probabilistic MR cerebellum atlas. Student t test of each cerebellar region and the correction for multiple comparisons were performed.

RESULTS

The volumes of four regions, namely right VIIIa, right VIIIb, left X, and right X, were significantly increased by approximately 7.43% to 8.25% in the AIS compared with the control group. Statistically, the results suggested that the cerebellar volume in AIS patients was larger compared with normal controls in the cerebellum regions of prepyramidal-prebiventer and intrabiventer fissures, intrabiventer and secondary fissures, and floccular-nodular (X)-posterolateral fissure to the inferior hemispheric margin.

CONCLUSIONS

The functions of the affected regions involve motor control, somatosensory, working memory, language, and response to visual stimulation. We conclude that the volume difference could be compensatory consequences in the central nervous system because of the persistent effort in AIS patients to maintain the body balance given the asymmetric spine.

Cortical shape and curvedness analysis of structural deficits in remitting and non-remitting depression

In morphometric neuroimaging studies, the relationship between brain structural changes and the antidepressant treatment response in patients with major depressive disorder has been explored to search depression-trait biomarkers. Although patients were treated with serotonin-related drugs, whether the same treatment resulted in remission and non-remission in depressed patients is currently under investigation. We recruited 25 depressed patients and 25 healthy controls and acquired volumetric magnetic resonance imaging of each participant. We used the shape index and curvedness to classify cortical shapes and quantify shape complexities, respectively, in studying the pharmacological effect on brain morphology. The results showed that different regions of structural abnormalities emerged between remitting and non-remitting patients when contrasted with healthy controls. In addition to comparing structural metrics in each cortical parcellation, similar to the traditional voxel-based morphometric method, we highlighted the importance of structural integrity along the serotonin pathway in response to medication treatment. We discovered that disrupted serotonin-related cortical regions might cause non-remission to antidepressant treatment from a pharmacological perspective. The anomalous areas manifested in non-remitting patients were mainly in the frontolimbic areas, which can be used to differentiate remitting from non-remitting participants before medication treatment. Because non-remission is the failure to respond to treatment with serotonin-related drugs, our method may help clinicians choose appropriate medications for non-remitting patients.

Recent advances in structural MRI in Parkinson’s disease and atypical parkinsonian syndromes

SUMMARY In the past 2 years, technical developments in conventional and advanced MRI, such as ultra-high-field MRI or mapping of brain mineralization, has allowed novel insights into the nature of Parkinson’s disease (PD) and atypical parkinsonian syndromes, which may aid diagnostic accuracy and differential diagnosis. In addition, sophisticated post-processing analyses, such as morphometry- and surface-based classifications and automated whole-brain analyses, have become available; in PD, this has led to direct visualization of structural substantia nigra abnormalities, monitoring disease progression or screening for brain atrophy associated with dementia. Based on conventional MRI, new MRI rating scales have been established for progressive supranuclear palsy and multiple system atrophy and have been further assessed with a view to their diagnostic accuracy. Clinicopathological series of patients with tauopathies imply that correlations between clinical syndromes, imaging patterns and underlying histopathology are not always strong. Here, some of the issues related to conventional and advanced MRI for the diagnostic accuracy of PD and atypical parkinsonian syndromes are reviewed.