T2*-weighted MRI differentiates multiple system atrophy from Parkinson's disease

To compare the ability of T2*-weighted gradient echo (GE) and T2-weighted fast spin echo images to distinguish between patients with idiopathic PD and multiple system atrophy (MSA), the authors studied 15 patients with probable MSA, 40 patients with PD, and 17 healthy control subjects. Hypointense putaminal signal changes were more often observed in MSA than in PD using T2* but not T2-weighted images, indicating that T2*-weighted GE sequences are of diagnostic value for patients with parkinsonism.     

Levodopa-induced sleepiness in the Parkinson variant of multiple system atrophy.

Recent observations suggest that levodopa can induce irresistible sleep onset in multiple system atrophy (MSA). Therefore, we assessed sleepiness during a levodopa challenge in 17 MSA compared with 23 Parkinson's disease (PD) patients using the Stanford Sleepiness Scale (SSS). SSS scores during the levodopa challenge compared with baseline were significantly increased in the MSA compared with the PD group. These findings suggest greater potential of levodopa to induce sleepiness in MSA compared with PD, which may be related to differences in basal ganglia and brainstem pathology between the two disorders.     

Voxel-based morphometry detects cortical atrophy in the Parkinson variant of multiple system atrophy.

To determine magnetic resonance imaging (MRI) patterns of brain atrophy in parkinsonian syndromes, we applied voxel-based morphometry (VBM) to segmented gray matter, white matter, and cerebrospinal fluid compartments of T(1)-weighted brain volumes of 12 patients with probable multiple system atrophy-parkinson variant (MSA-P) and 12 Parkinson's disease patients, comparing them with 12 normal controls matched for age. In comparison to controls, a cortical atrophy pattern was observed in MSA-P patients with significant clusters of volume loss in primary sensorimotor cortices bilateral, supplementary motor areas bilateral, right premotor cortex, prefrontal cortex bilateral (middle frontal gyri) and insular cortices bilateral; subcortical atrophy occurred bilaterally in caudate nuclei and putamen as well as in the midbrain. Furthermore, an enlargement of the cerebrospinal fluid compartment was found in the lateral ventricles, third ventricle, perimesencephalic and cerebellomedullar cavities. In PD patients, significant atrophy only occurred in left caudate head with enlargement of left lateral ventricle. Comparing MSA-P to PD patients, MSA-P showed a similar cortical pattern of atrophy as compared to controls. We conclude that VBM reveals selective cortical atrophy in patients with MSA-P affecting primary and higher order motor areas as well as prefrontal and insular cortices. Further studies are required to determine clinical and/or subclinical correlates of cortical atrophy in MSA-P.     

Diffusion-weighted magnetic resonance imaging differentiates Parkinsonian variant of multiple-system atrophy from progressive supranuclear palsy.

Progressive supranuclear palsy (PSP) and the parkinsonian variant of multiple-system atrophy (MSA-P) may present with a similar phenotype. Magnetic resonance diffusion-weighted imaging (DWI) has been shown to be a sensitive discriminator of MSA-P from Parkinson's disease (PD). We studied 20 PSP, 11 MSA-P, 12 PD patients and 7 healthy controls in order to investigate whether regional apparent diffusion coefficients (rADCs) help distinguish PSP and MSA-P; whether rADCs are correlated with clinical disease severity scores; and the relationship between brainstem and cerebellar volumes and rADCs in PSP and MSA-P. The Unified Parkinson's Disease Rating Scale, Hoehn and Yahr score, Mini Mental State Examination, and frontal assessment battery were recorded in all patients. Regional ADCs were measured in the middle cerebellar peduncle (MCP), caudal and rostral pons, midbrain, decussating fibers of the superior cerebellar peduncle, thalamus, putamen, globus pallidus, caudate nucleus, corpus callosum, frontal and parietal white matter, as well as the centrum semiovale. In MSA-P, rADCs in the MCP and rostral pons were significantly greater than in PSP (P < 0.001 and 0.009) and PD (P < 0.001 and = 0.002). Stepwise logistic regression revealed that the MCP rADC distinguishes MSA-P from PSP with a sensitivity of 91% and a specificity of 84%. Increased brainstem rADCs were associated with motor deficit in MSA-P and PSP. Increased rADCs in the pons and MCP were associated with smaller pontine and cerebellar volumes in MSA-P. rADCs distinguish MSA-P from PSP. These have a clinical correlate and are associated with reduced brainstem and cerebellar volumes.     

Eye of the tiger-like MRI in parkinsonian variant of multiple system atrophy

Parkinsonian variant of multiple system atrophy (MSA-P) clinically presents as autonomic dysfunction with parkinsonian features. Parkinsonian features include bradykinesia, rigidity, tremor, postural instability and poor levo-dopa response. Neuropathologically, MSA-P is characterized by selective neuronal loss and gliosis mainly affecting the putamen and caudate nucleus, substantia nigra, olivopontocerebellar pathway and intermediolateral cell column of the spinal cord. Therefore, the target of magnetic resonance imaging (MRI) is focused on signal changes or volume reduction on putamen, including putaminal slit, gliosis by diffusion studies and reduction of putaminal volume. There have been no reports describing clinical manifestations of MSA-P with imaging abnormalities over globus pallidus. Here, we describe three patients with typical presentations of MSA-P with autonomic dysfunction and disturbances of axial motor function with minimal appendicular symptoms, including postural instability and gait difficulties. MRI showed symmetrical hyperintensity over the center of globus pallidus surrounded by a mild low-signal rims at T2-weighted image that is similar to that of eye of the tiger sign except for the marked hypointense rims. Dopamine transporter scans showed symmetric reduction of uptake over bilateral basal ganglia. This is the first report concerning these unusual imaging findings in MSA-P patients and we believe there is a subgroup of MSA-P with clinical presentation of axial impairment and symmetrically abnormal signal changes of globus pallidus in MRI.     

Cerebrospinal fluid analysis differentiates multiple system atrophy from Parkinson's disease.

We investigated whether cerebrospinal fluid (CSF) analysis discriminates between idiopathic Parkinson's disease (PD; n = 35) and multiple system atrophy (MSA; n = 30). The median CSF concentration of the neurotransmitter metabolites 5-hydroxyindolacetic acid (5-HIAA) and 3-methoxy-4-hydroxyphenylethyleneglycol (MHPG) was reduced significantly (49-70%) in MSA compared to PD. In contrast, several brain-specific proteins (tau, neuron-specific enolase, myelin basic protein) were elevated (130-230%) in MSA compared with those in PD. A combination of CSF tau and MHPG discriminated PD from MSA (adjusted odds ratios: tau, 27.2; MHPG, 0.14). Our data suggest that the more progressive and widespread neurodegenerative nature of MSA, as compared with PD, is reflected in the composition of CSF. We propose that CSF analysis may become part of the diagnostic work-up of patients with parkinsonian syndromes.     

Cerebral atrophy in multiple system atrophy by MRI

Cranial magnetic resonance images (MRI) of the cerebral areas of 40 patients with multiple system atrophy (MSA) and of 61 age-matched controls were analyzed. The cerebral area of MSA patients was 131. 95+/-15.89 cm(2) (mean+/-S.D.), which was significantly smaller than that of normal controls at 149.01+/-10.93 cm(2) (P<0.0001). All 23 MSA cases subjected to the MRI study over a 1-year period showed progressive cerebral atrophy, and the atrophy rate was 2.46+/-1. 66%/year. There were no significant differences within the MSA subtypes or between gender. The progression of cerebral atrophy in MSA correlated more with duration (r=-0.634) than age (r=-0.421). We conclude that MRI findings throughout the course of MSA suggest progressive cerebral atrophy, which is common in all subtypes and reflects duration of the disease rather than age.     

Subcortical atrophy and perfusion patterns in Parkinson disease and multiple system atrophy

BackgroundThe clinical differentiation between Parkinson disease (PD) and multiple system atrophy (MSA) is difficult.ObjectivesArterial spin labeling (ASL) is an advanced MRI technique that obviates the use of an exogenous contrast agent for the estimation of cerebral perfusion. We explored the value of ASL in combination with structural MRI for the differentiation between PD and MSA.MethodsNinety-four subjects (30 PD, 30 MSA and 34 healthy controls) performed a morphometric and ASL-MRI to measure volume and perfusion values within basal ganglia and cerebellum. A region-of-interest analysis was performed to test for structural atrophy and regional blood flow differences between groups.ResultsMSA patients showed higher subcortical atrophy than both PD patients and HC, while no differences were observed between the latter. MSA and PD showed lower volume-corrected perfusion values than HC in several cerebellar areas (Crus I, Crus II, right VIIb, right VIIIa, right VIIIb), right caudate and both thalami. MSA and PD patients displayed similar perfusion values in all aforementioned areas, but the right cerebellar area VIIIb (lower in MSA) and right caudate and both thalami (lower in PD). Similar results were obtained when comparing PD and MSA patients with the parkinsonian variant.ConclusionsA perfusion reduction was equally observed in both MSA and PD patients in cerebellar areas that are putatively linked to cognitive (i.e., executive) rather than motor functions. The observed hypo-perfusion could not be explained by atrophy, suggesting the involvement of the cerebellum in the pathophysiology of both MSA and PD.     

Loss of dopaminergic responsiveness in a double lesion rat model of the Parkinson variant of multiple system atrophy.

The Parkinson variant of multiple system atrophy (MSA-P) is a distinct atypical parkinsonian disorder with a loss of dopaminergic neurons comparable to that found in Parkinson's disease (PD). The additional loss of striatopallidal projections is thought to account for levodopa unresponsiveness in MSA-P. Whereas histological features of MSA-P have been successfully reproduced in the double lesion rat model, loss of levodopa responsiveness has so far not been demonstrated. In the current study, 6-hydroxydopamine (6-OHDA) induced unilateral lesions of the substantia nigra produced a marked contralateral forelimb stepping deficit, which improved significantly after challenge with levodopa (P < 0.001). This response was abolished by the subsequent striatal quinolinic acid (QA) lesion. In the cylinder test, the marked asymmetry observed after 6-OHDA lesioning was reversed by levodopa to baseline levels. After QA, cylinder test performance under levodopa failed to reach baseline (P = 0.001) or 6-OHDA + levodopa (P = 0.002) levels. Nigral cell loss (90% +/- 5%) correlated with both stepping test (r = 0.608; P = 0.008) and cylinder test results (r = 0.656; P = 0.005). Lesion extent of the dorsal striatum correlated significantly with the loss of levodopa response (r = 0.593; P = 0.01) in the stepping test. These findings contribute further to the behavioral characterization of the double lesion rat model of MSA, improving its value in the evaluation of future neurorestorative strategies.     

REM sleep behaviour disorder differentiates pure autonomic failure from multiple system atrophy with autonomic failure

Ten patients with primary autonomic failure, followed up in aprospective clinical and laboratory study, were finally diagnosed aspure autonomic failure or multiple system atrophy with autonomic failure. Polysomnographic studies were performed in all patients. Whereas all four patients with multiple system atrophy complained ofsleep related episodes suggesting REM sleep behaviour disorder (RBD)confirmed by polysomnography, RBD remained absent in the remaining sixpatients with pure autonomic failure. The data indicate that RBD is animportant clinical feature, often heralding multiple system atrophy,but which is absent throughout the course of pure autonomic failure;its recognition can thus be useful in the prognostic evaluation ofearly primary autonomic failure syndromes.

     

多系统萎缩的临床与MRI特征

目的探讨多系统萎缩(MSA)的临床与MRI特征及其对临床亚型诊断的意义。方法回顾性分析28例MSA患者的临床及MRI资料。结果橄榄脑桥小脑萎缩(OPCA)以小脑体征(75.0%)突出,MRI表现为脑桥萎缩(91.7%)、小脑蚓部萎缩(91.7%),第四脑室扩大(83.8%),T2WI出现脑桥、小脑对称性高信号(63.6%)及脑桥十字征;纹状体黑质变性(SND)以锥体外系症状(80.0%)明显,MRI改变多位于基底节核团,表现为壳核萎缩(60.0%),T2WI示壳核外侧缘缝隙样高信号(80.0%);ShyDrager综合征(SDS)以自主神经症状(81.8%)为主,出现早且重,MRI未见特异性变化。结论MRI有助于提高MSA及其亚型诊断。脑桥萎缩、T2WI高信号改变,尤其是脑桥十字征的出现有助于OPCA诊断;壳核萎缩与T2WI壳核外侧缘缝隙样高信号改变支持SND诊断。     

Cardiovascular autonomic nervous system evaluation in Parkinson disease and multiple system atrophy

BackgroundAutonomic nervous system dysfunction (ANSd) heralds or follows motor symptoms (MS) in Parkinson disease (PD), but may precede years and progress more rapidly in multiple system atrophy (MSA). Cardiac dysautonomia severity correlates with disabling symptoms thus a Cardiac Autonomic Nervous System Evaluation protocol (CANSEp) is useful to assess ANSd in PD and MSA patients.Methods and resultsConsecutive patients with PD or MSA were studied. The severity of MS was quantified with UPDR III and Hoehn/Yahr scales. CANSEp consisted of the 5-test Ewing protocol (EP) and Heart Rate Variability analysis (HRVa), in time-domain (TD) and frequency-domain (FD).36 patients with parkinsonian symptoms (23 PD, 13 MSA) and 40 healthy controls were studied. Parkinsonism was more severe in MSA, comparing UPDR III and Hoehn/Yahr scales (p < 0.0001). Higher EP's scores were found in MSA (mean 5.1 ± 1.98) compared to PD (mean 3.5 ± 2) and controls (score 0.25 ± 0.1). TD and FD-HRVa were abnormal in PD and MSA, compared to controls. In PD depression of vagal tone was predominant during sleep, whereas in MSA depression of sympathetic tone prevailed during daily activity.ConclusionsWhereas its specificity is very high, the sensitivity of the EP was only 43.5% in PD and 76.9% in MSA. HRVa improved diagnosis accuracy in 10 patients, unidentified by the EP alone, with overall sensitivity of 65.2% in PD and 92.3% in MSA. Thus CANSEp provides a better assessment of cardiovascular dysautonomia in parkinsonian syndromes, useful to differentiate PD from MSA and to address clinical and pharmacological management.     

Evaluating posterolateral linearization of the putaminal margin with magnetic resonance imaging to diagnose the Parkinson variant of multiple system atrophy.

The objective was to develop a simple method for evaluating putaminal atrophy in patients with the Parkinson variant of multiple system atrophy (MSA-P). We used magnetic resonance imaging to study 9 patients with MSA-P, 24 patients with cerebellar variants of multiple system atrophy (MSA-C), 38 patients with Parkinson's disease (PD), and 27 healthy control subjects. Posterolateral linearization of the putaminal margin was semiquantitatively scored and the putaminal area per intracranial area was calculated as the adjusted putaminal area. There was a negative correlation between the linearization scores and adjusted putaminal areas (r = -0.43, P < 0.001), such that the mean adjusted putaminal area in the group without putaminal linearization (0.0148 +/- 0.0022) was greater than that of the group with linearization (0.0124 +/- 0.0029, P < 0.005). Moreover, the occurrence of putaminal linearization was significantly higher in MSA-P patients (88.8%) than in MSA-C (8.3%), PD (7.9%) and healthy subjects (7.4%; P < 0.005). Putaminal linearization was a highly sensitive (0.89) and specific (0.91) measure for differentiating MSA-P. Our results suggest that evaluating posterolateral putaminal linearization is useful for assessing putaminal atrophy and for differentiating MSA-P from MSA-C, PD, and healthy subjects.