title: Comparison of diffusion-weighted imaging and [123I]IBZM-SPECT for the differentiation of patients with the Parkinson variant of multiple system atrophy from those with Parkinson's disease.
abstract: Both dopamine D2 receptor (D2R) binding single-photon emission computed tomography (SPECT) with [123I]iodobenzamide (IBZM) and diffusion-weighted imaging (DWI) have been shown to contribute to the differential diagnosis of patients with the Parkinson variant of multiple system atrophy (MSA-P) and Parkinson's disease (PD). We aimed to compare these two routinely available functional imaging modalities in differentiating patients with MSA-P from PD. For this purpose, results obtained by DWI and IBZM-SPECT were intraindividually compared in a cross-sectional study of 15 MSA-P and 17 PD patients matched for age and disease duration. The activity ratios of striatal to frontal cortex uptake (S/FC ratio) were used as a semiquantitative measure of the relative density of basal ganglia dopamine receptors labeled by IBZM. Regional apparent diffusion coefficients (rADC) were determined in the striatum. MSA-P patients had significantly lower S/FC ratios and significantly higher striatal rADCs than both PD patients and healthy volunteers. There were no significant differences in S/FC ratios and striatal rADC between PD patients and healthy volunteers. Sensitivity of IBZM-SPECT versus DWI for the differentiation of MSA-P from PD was 80% versus 93%, specificity 71% versus 100%, the predictive accuracy 75% versus 97%, the positive predictive value 71% versus 100%, and the negative predictive value 80% versus 94%. Striatal rADCs had a significant higher overall predictive accuracy than D2R binding with IBZM. In summary, our data suggest that DWI may be more accurate compared to IBZM-SPECT in the differential diagnosis of MSA-P versus PD.
authors.affiliation: Department of Neurology, University of Innsbruck, Innsbruck, Austria.
authors.forename: Klaus
authors.initials: K
authors.lastname: Seppi
authors.forename: Michael F H
authors.initials: MF
authors.lastname: Schocke
authors.forename: Eveline
authors.initials: E
authors.lastname: Donnemiller
authors.forename: Regina
authors.initials: R
authors.lastname: Esterhammer
authors.forename: Christian
authors.initials: C
authors.lastname: Kremser
authors.forename: Christoph
authors.initials: C
authors.lastname: Scherfler
authors.forename: Anja
authors.initials: A
authors.lastname: Diem
authors.forename: Werner
authors.initials: W
authors.lastname: Jaschke
authors.forename: Gregor K
authors.initials: GK
authors.lastname: Wenning
authors.forename: Werner
authors.initials: W
authors.lastname: Poewe
mesh_terms: D001479:Basal Ganglia / Q000098:blood supply; D001549:Benzamides; D003287:Contrast Media; D003342:Corpus Striatum / Q000098:blood supply*; D003430:Cross-Sectional Studies; D038524:Diffusion Magnetic Resonance Imaging; D005500:Follow-Up Studies; D005625:Frontal Lobe / Q000098:blood supply*; D006801:Humans; D008875:Middle Aged; D019578:Multiple System Atrophy / Q000150:complications* / Q000175:diagnosis* / Q000000981:diagnostic imaging; D010300:Parkinson Disease / Q000150:complications* / Q000175:diagnosis* / Q000000981:diagnostic imaging; D011237:Predictive Value of Tests; D011759:Pyrrolidines; D012680:Sensitivity and Specificity; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: D001549:Benzamides; D003287:Contrast Media; D011759:Pyrrolidines; C055743:3-iodo-2-hydroxy-6-methoxy-N-((1-ethyl-2-pyrrolidinyl)methyl)benzamide