Clinical usefulness of MRI in multisystem atrophy

Voxel based comparison of glucose metabolism in the differential diagnosis of the multiple system atrophy using statistical parametric mapping

OBJECTIVE

A differential diagnosis of idiopathic parkinsonian disease (IPD) and multiple system atrophy (MSA) is difficult due to their common signs and symptoms. The aim of this 18F-2-fluoro-2 deoxyglucose (18F-FDG) positron emission tomography (PET) study was to compare the regional cerebral glucose metabolism in MSA with that in IPD by statistical parametric mapping (SPM) and image registration.

METHODS

The 18F-FDG PET images of MSA and IPD patients were assessed by SPM and image registration to determine metabolic patterns that may be useful in differentiating between the two groups. Eleven patients with MSA, eight patients with IPD and 22 healthy controls participated in the study.

RESULTS

The IPD patients were found to have a significant glucose hypometabolism in comparison with the healthy controls in the prefrontal, lateral frontal, and parietotemporal cortices, and the cingulate and caudate areas (p< or =0.01, 100 voxel-level). In patients with MSA, hypometabolism was observed in the putamen, pons, and cerebellum in comparison with the healthy controls and IPD patients.

CONCLUSION

The voxel-based analysis of 18F-FDG PET images showed detailed differences between IPD and MSA, which may be useful in differentiating the two disease entities, as evidenced by the correlation of glucose metabolism with disease severity and dopamine agonist medication. The mapping analysis of 18F-FDG PET images might be a useful adjunctive method of a differential diagnosis for parkinsonism in a clinical setting.

Different metabolic patterns analysis of Parkinsonism on the 18F-FDG PET

Idiopathic Parkinson's disease (IPD), progressive supranuclear palsy (PSP) and multiple system atrophy (MSA) are the most common movement disorders associated with neurodegenerative disease. A clinical differential diagnosis of IPD and atypical Parkinsonian disorders, such as MSA and PSP, is often complicated by the presence of symptoms common to both groups. Since Parkinsonism has a different pathophysiology in the cortical and subcortical brain structures, assessing the regional cerebral glucose metabolism may assist in making a differential diagnosis of Parkinsonism. The 18F-FDG PET images of IPD, MSA and PSP were assessed using statistical parametric mapping (SPM) in order to determine the useful metabolic patterns. Twenty-four patients with Parkinsonism: eight patients (mean age 67.9 +/- 10.7 years; M/F: 3/5) with IPD, nine patients (57.9 +/- 9.2 years; M/F: 4/5) with MSA and seven patients (67.6 +/- 4.8 years; M/F: 3/4) with PSP were enrolled in this study. All patients with Parkinsonism and 22 age-matched normal controls underwent 18F-FDG PET, (after 370 MBq 18F-FDG). The three groups and the individual IPD, MSA and PSP patients were compared with a normal control group using a two-sided t-test of SPM (uncorrected P < 0.01, extent threshold > 100 voxel). The IPD, MSA and PSP groups showed significant hypometabolism in the cerebral neocortex compared to the normal control group. The MSA group showed significant hypometabolism in the putamen, pons and cerebellum compared to the normal controls and IPD groups. In addition, PSP showed significant hypometabolism in the caudate nucleus, the thalamus, midbrain and the cingulate gyrus compared to the normal controls, the IPD and the MSA groups. In conclusion, an assessment of the 18F-FDG PET images using SPM may be a useful adjunct to a clinical examination when making a differential diagnosis of Parkinsonism.

Characterization of ataxias with magnetic resonance imaging and spectroscopy

A wide variety of autosomal transmitted ataxias exist and their ultimate characterization requires genetic testing. Common clinical characteristics among different ataxia types complicate the choice of the appropriate genetic test. Magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) generally show cerebellar or cerebral atrophy and perturbed metabolite levels which differ between ataxias. In order to help the clinician accurately identify the ataxia type, reported MRI and MRS data in different brain regions are summarized for more than 60 different types of autosomal inherited and sporadic ataxias.