[¹⁸F]FDG-PET is superior to [¹²³I]IBZM-SPECT for the differential diagnosis of parkinsonism.
OBJECTIVE
Imaging of regional cerebral glucose metabolism with PET and striatal dopamine D2/D3 receptors (D2R) with SPECT improves the differential diagnosis of parkinsonism. We prospectively investigated 1) the diagnostic merits of these approaches in differentiating between Lewy body diseases (LBD; majority Parkinson disease [PD]) and atypical parkinsonian syndromes (APS); 2) the diagnostic value of [¹⁸F]fluorodeoxyglucose (FDG)-PET to differentiate among APS subgroups.


METHODS
Ninety-five of 107 consecutive patients with clinically suspected APS referred for imaging were recruited. [¹⁸F]FDG-PET scans were analyzed by visual assessment (including individual voxel-based statistical maps). Based on a priori defined disease-specific patterns, patients with putative APS were differentiated from LBD (first level) and allocated to the subgroups multiple system atrophy (MSA), progressive supranuclear palsy (PSP), or corticobasal degeneration (CBD) (second level). [¹²³I] iodobenzamide (IBZM)-SPECT datasets were subjected to an observer-independent regions-of-interest analysis to assess striatal D2R availability. Movement disorder specialists made final clinical diagnoses after a median follow-up time of 12 months.


RESULTS
Seventy-eight patients with clinically verified APS (n = 44) or LBD (n = 34) were included in the statistical analysis. The area under the receiver operating characteristic curve for discrimination between APS and LBD was significantly larger for [¹⁸F]FDG-PET (0.94) than for [¹²³I]IBZM-SPECT (0.74; p = 0.0006). Sensitivity/specificity of [¹⁸F]FDG-PET for diagnosing APS was 86%/91%, respectively. Sensitivity/specificity of [¹⁸F]FDG-PET in identifying APS subgroups was 77%/97% for MSA, 74%/95% for PSP, and 75%/92% for CBD.


CONCLUSIONS
The diagnostic accuracy of [¹⁸F]FDG-PET for discriminating LBD from APS is considerably higher than for [¹²³I]IBZM-SPECT. [¹⁸F]FDG-PET reliably differentiates APS subgroups.
Department of Neurology, University of Freiburg, Germany. sabine.hellwig@uniklinik-freiburg.de
Sabine
S
Hellwig
Florian
F
Amtage
Annabelle
A
Kreft
Ralph
R
Buchert
Oliver H
OH
Winz
Werner
W
Vach
Timo S
TS
Spehl
Michel
M
Rijntjes
Bernhard
B
Hellwig
Cornelius
C
Weiller
Christian
C
Winkler
Wolfgang A
WA
Weber
Oliver
O
Tüscher
Philipp T
PT
Meyer
D000368:Aged; D003937:Diagnosis, Differential; D019788:Fluorodeoxyglucose F18; D005500:Follow-Up Studies; D006801:Humans; D007462:Iodobenzenes; D020961:Lewy Body Disease / Q000175:diagnosis; D008297:Male; D008875:Middle Aged; D019578:Multiple System Atrophy / Q000175:diagnosis; D019636:Neurodegenerative Diseases / Q000175:diagnosis; D010300:Parkinson Disease / Q000175:diagnosis; D020734:Parkinsonian Disorders / Q000175:diagnosis*; D049268:Positron-Emission Tomography / Q000379:methods*; D013494:Supranuclear Palsy, Progressive / Q000175:diagnosis; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*
D007462:Iodobenzenes; C426805:idobenzamide; D019788:Fluorodeoxyglucose F18