北海道脳神経疾患研究所医誌第21巻

2010．12．P71〜74

Diagnostic Values of Diffusion Weighted Imaging
for Differentiating Multiple System Atrophy from Parkinson's Disease
Kazuya SAKO, M.D., Akiko TAKEUCHI, M.D., Takenori ABE, M.D., Hisataka TANAKA, M.D.,
Atsuko NIHIRA, M.D., and Masahiro MIZOBUCHI, M.D.
Department of Neurology, Nakamura Memorial Hospital and Hokkaido Brain Research Foundation, Sapporo,Japan
Abstract:
We investigated apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values using diffusionweighted imaging (DWI) MRI in multiple system atrophy (MSA) and Parkinson's disease (PD) to assess the differential diagnostic values. Differentiation of MSA from PD is clinically important because these disorders manifest dissimilar treatment response and prognosis. Recently, quantitative analysis of DWI associated values was reported tobe useful for detecting the early imaging changes of MSA. We measured ADC and FA values in the pons, bilateral
middle cerebellar peduncle and putamen comparing MSA and PD patients. We placed circular shaped regions ofinterest (ROI) in the each area. Subjects were 10 probable MSA patients (mean age 66 years, mean disease duration 5.5 years) and 15 Parkinson's disease patients (mean age 70 years, mean disease duration 8.1 years). Normal
Heart/ Mediastinum ratio of cardiac MIBG scintigraphy was applied to confirm the further supporting evidence ofMSA. ADC values in the all ROIs of pons, middle cerebellar peduncle, and putamen indicated significantly higher
in MSA than PD. ADC values averaging all ROIs seemed best to discriminate MSA from PD. ADC values tend tobe higher correlating with longer disease duration and severer clinical symptoms in MSA patients. We found no significant correlation with disease duration nor severity in PD patients. FA values in MSA patients showed lower inthe pons and middle cerebellar peduncle, but in the putamen compared with PD. Lower FA values in the pons andmiddle cerebellar peduncle were detected as longer duration and severer symptoms in MSA. ADC and FA values inthe brainstem and putamen of MSA patients were revealed to differ from PD. The changes of these values tended tobe evident in the more advanced MSA patients, suggesting these quantitative manners might reflect pathologicalprogression in MSA. DWI appears to be a useful diagnostic tool for differential diagnosis of MSA from PD.
Keywords: Multiple system atrophy, Diffusion weighted imaging, Apparent diffusion coefficient, Fractional
anisotropy (FA)−71−

Introduction:
Differentiation of parkinsonian variant of multiple
system atrophy (MSA) from Parkinson's disease (PD)is clinically important because these disorders manifest dissimilar treatment response and prognosis.
Characteristic MRI findings of MSA, such as dorsolateral putaminal hyperintensity (DPH) or hot cross bun(HCB) sign, were not always obvious especially in theearly stage of the disease. Recently, quantitative
analysis of diffusion weighted imaging (DWI) associated values were reported to be useful for detecting
the early imaging changes of MSA. We therefore
investigated apparent diffusion coefficient (ADC) andfractional anisotropy (FA) values using DWI methods
in MSA and PD to assess the differential diagnosticvalues.
Methods:
Subjects were 10 probable MSA cases (mean age65.4 years, mean disease duration 5.5 years) and 15
PD cases (mean age 70.1 years, mean disease duration 8.1 years). Table 1 summarized profiles of subjects including Hohen-Yahr (H-Y) stages. H-Y stages
were supposedly applied for the estimation of motor

Fig. 1 H/M ratio of cardiac MIBG scintigraphy: MSA vs.
PD
Normal H/M > 2.0

ratio in PA tended to decrease lower than 1.8. We
measured regional ADC (rADC) and regional FA(rFA) values in the pons, bilateral middle cerebellar
peduncles (MCP) and putamens comparing MSA andPD cases. We performed with 1.5 T MR scanner(TR/TE=3000/60, b=1000, Siemens, Germany) and circular shaped regions of interest (ROI) were placed in
the each areas (Fig. 2).

Table 1 Characteristics of subjects
disability of MSA cases in order to make a rough comparison. Profiles of both groups were well matchedand statistical significant differences were not evident. Normal Heart/Mediastinum (H/M) ratio of cardiac MIBG (meta-iodobenzylguanidine) scintigraphy
was also applied to confirm the further supporting
evidence for MSA (Fig. 1). On the other hand, H/M

Fig. 2 ROIs placed in each area in MRI
Upper left: ROIs for putamens in ADC image
Upper right: ROIs for pons and MCPs in ADC
image
Lower left: ROIs for putamens in FA image
Lower right: ROIs for pons and MCPs in FA image※ Values averaging in 6 ROIs for putamen※ Values averaging in 3 ROIs pons and MCPs forpons−72−

Results:
ADC values averaging the each ROIs of pons (ponsand MCPs) and putamens (bilateral putamens) indicated significantly higher in MSA than PD (Fig. 3).
ADC values averaging all ROIs seemed best to discriminate MSA from PD. FA values in MSA patients
showed lower in the pons, but in the putamens com-Fig. 5 rADC and rFA in relation to the duration of MSA

Fig. 3 rADC values in MSA vs. PD
Left: Putaminal rADC, Right: Pontine rADC

Fig. 6 rADC and rFA in relation to motor disability (H-Y)
of MSA

Fig. 4 rFA values in MSA vs. PD
Left: Putaminal rADC, Right: Pontine rADC

pared with PD (Fig. 4). ADC values tend to be higher
correlating with longer disease duration and severer
motor symptoms in MSA patients (Fig. 5). No significant correlation with disease duration nor severity inPD patients (not shown). Lower FA values in the pons
were detected as longer duration and severer motor
symptoms in MSA (Fig. 6).

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Discussion:
Conventional MRI changes suggesting MSA such as
DPH or HCB sign reportedly fail to distinguish MSA
from PD up to nearly half of early staged cases 1).
Reduction of H/M ratio of cardiac MIBG scintigraphyis proven to be useful for diagnosing PD, but the decision must be cautious since some cases of MSA also
show the diminished ratio. Köllensperger describedthat DWI was superior to MIBG scintigraphy in thedifferential diagnosis of parkinsonian variant of MSA
versus PD2). Several investigators have indicatedclinical advantages of DWI utilizing ADC and/or FA
values in discriminating MSA from PD2-6). DWI values can detect early pathological involvement prior toconventional MRI in MSA. Ito demonstrated combined analysis of both ADC and FA values in all ROIs
including pons, cerebellum and putamen, was more
useful than only one4). Our data also supported thesimilar tendency.
These alterations of DWI values in brainstem could
be detected even in parkinsonian variant of MSA.
Subtle early degenerative changes in brainstem may
explain these results. We showed that increased total
ADC and reduced pontine FA values were correlated
well with the disease duration and motor severity.
Quantitative DWI values may provide potent markersof disease progression.

2) Köllensperger M, Seppi K, Liener C, et al: Diffusionweighted imaging best discriminates PD fromMSA-P: A comparison with tilt table testing andheart MIBG scintigraphy. Mov Disord, 2007; 22:1771-1776.
3) Schocke MF, Seppi K, Esterhammer R, et al: Diffusion-weighted MRI differentiates the Parkinson
variant of multiple system atrophy from PD. Neurology, 2002; 58: 575-580.
4) Ito M, Watanabe H, Kawai Y, et al: Usefulness of
combined fractional anisotropy and apparent diffusion coefficient values for detection of involvementin multiple system atrophy. J Neurol Neurosurg
Psychiatry, 2007; 78: 722-728.
5) Seppi K, Schocke MF, Prennschuetz-Schuetzenau
K, et al: Topography of putaminal degeneration in
multiple system atrophy: a diffusion magnetic resonance study. Mov Disord, 2006; 21: 847-852.
6) Kanazawa M, Shimohata T, Terajima K, et al:
Quantitative evaluation of brainstem involvementin multiple system atrophy by diffusion-weighted
MR imaging. J Neurol, 2004; 251: 1121-1124.

Conclusions:
ADC and FA values in pons and putamen of MSA
patients were revealed to differ from PD. Thechanges of these values tended to be evident in themore advanced MSA patients, suggesting these quantitative manners might reflect pathological progression in MSA. DWI appears to be a useful diagnostic
tool for differential diagnosis of MSA from PD.
References:1) Schrag A, Kingsley D, Phatouros C, et al: Clinicalusefulness of magnetic resonance imaging in multiple system atrophy. J Neurol Neurosurg Psychiatry, 1998; 65: 65-71.

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