RESEARCH: Diffusion-weighted MRI differentiates the Parkinson variant of multiple system atrophy from PD

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Neurology 2002 Feb 26;58(4):575-80

Diffusion-weighted MRI differentiates the Parkinson

variant of multiple system atrophy from PD.

Schocke MF, Seppi K, Esterhammer R, Kremser C, Jaschke

W, Poewe W, Wenning GK.

Both authors contributed equally to this article. From

the Departments of Radiology (Drs. Schocke,

Esterhammer, Kremser, and Jaschke) and Neurology (Drs.

Seppi, Poewe, and Wenning), University of Innsbruck,

Austria.

Objective and Background: Routine MRI as well as MR

volumetry and MRS have been shown to contribute to the

differential diagnosis of the Parkinson variant of

multiple system atrophy (MSA-P) and PD. However, it is

currently unknown whether diffusion-weighted imaging

(DWI) discriminates these disorders.

METHODS: Ten patients with MSA-P (mean age, 64 years)

were studied, 11 with PD (mean age, 64 years), and

seven healthy volunteers (mean age, 59 years) matched

for age and disease duration. Regional apparent

diffusion coefficients (rADC) were determined in

different brain regions including basal ganglia, gray

matter, white matter, substantia nigra, and pons.

RESULTS: Patients with MSA-P had higher putaminal rADC

(median 0.791 x 10(3)/mm(2)/s) than both patients with

PD (median 0.698 x 10(3)/mm(2)/s, p < 0.001) and

healthy volunteers (median 0.727 x 10(3)/mm(2)/s, p <

0.001). There were no significant differences in

putaminal rADC between patients with PD and healthy

volunteers. Moreover, none of the putaminal rADC

values in the PD and control group surpassed the

lowest value in the MSA-P group. There were no

significant group differences in the rADC values

in other brain regions such as pons, substantia nigra,

globus pallidus, caudate nucleus, thalamus, or gray

and white matter. Putaminal rADC values correlated

significantly with Unified PD Rating Scale OFF scores

in patients with MSA as measured by the Spearman rank

test.

CONCLUSION: DWI, even if measured in the

slice direction only, is able to discriminate MSA-P

and both patients with PD and healthy volunteers on

the basis of putaminal rADC values. The increased

putaminal rADC values in Parkinson variant of multiple

system atrophy are likely to reflect ongoing striatal

degeneration, whereas most neuropathologic studies

reveal intact striatum in PD. Diffusion-weighted

imaging may represent a useful diagnostic tool that

can provide additional support for a diagnosis of

Parkinson variant of multiple system atrophy.

PMID: 11865135 [PubMed - in process]

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