The value of the dopamine D2/3 receptor ligand 18F-desmethoxyfallypride for the differentiation of idiopathic and nonidiopathic parkinsonian syndromes.
We evaluated the utility of the selective dopamine D(2/3) receptor ligand (18)F-desmethoxyfallypride ((18)F-DMFP) for the differential diagnosis of patients with idiopathic parkinsonian syndrome (IPS) and nonidiopathic parkinsonian syndrome (non-IPS). On the basis of the superior sensitivity of PET, we hypothesized that (18)F-DMFP should have properties for the differential diagnosis of these syndromes superior to what has been reported for the more conventional SPECT procedures.


METHODS
A series of 81 patients with parkinsonism (26 women, 55 men; mean age +/- SD, 68 +/- 11 y) were included in this retrospective analysis. A 30-min (18)F-DMFP PET recording was acquired starting 1 h after injection of the tracer (180-200 MBq, intravenously). The specific binding (SB) in divisions of the striatum was calculated relative to the occipital cortex using an observer-independent semiautomatic volume-of-interest-based technique. The optimal SB threshold was defined by means of receiver-operating-characteristic analysis, which was also used for the evaluation of the diagnostic performance of SB, ratios between striatal subregions, and absolute asymmetries in SB.


RESULTS
Significant differences (P < 0.001) were found in striatal SB between IPS and non-IPS, most notably in the posterior putamen, for which the diagnostic power for discrimination of IPS and non-IPS was the highest (sensitivity, 87%; specificity, 96%; and accuracy, 91%). A further gain of diagnostic power (sensitivity, 92%; specificity, 96%; and accuracy, 94%) was obtained through discriminant analysis combining 3 parameters: SB of the posterior putamen, the posterior-to-anterior putamen ratio, and the posterior putamen-to-caudate ratio.


CONCLUSIONS
(18)F-DMFP PET is useful for the differential diagnosis of IPS and non-IPS in patients with parkinsonism. The findings are consistent with relative sparing of D(2/3) receptors in the dopamine-denervated putamen of IPS patients, in contrast to a more substantial loss of striatal dopamine receptors in non-IPS patients. The PET procedure for this differential diagnosis was superior to the reported experience with (123)I-iodobenzamide SPECT.
Department of Nuclear Medicine, University of Munich, Munich, Germany. christian.lafougere@med.uni-muenchen.de
Christian
C
la Fougère
Gabriele
G
Pöpperl
Johannes
J
Levin
Björn
B
Wängler
Guido
G
Böning
Christopher
C
Uebleis
Paul
P
Cumming
Peter
P
Bartenstein
Kai
K
Bötzel
Klaus
K
Tatsch
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003937:Diagnosis, Differential; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008024:Ligands; D008297:Male; D008875:Middle Aged; D017072:Neostriatum / Q000378:metabolism; D010300:Parkinson Disease / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000378:metabolism*; D049268:Positron-Emission Tomography; D012372:ROC Curve; D017448:Receptors, Dopamine D2 / Q000378:metabolism*; D050637:Receptors, Dopamine D3 / Q000378:metabolism*; D012189:Retrospective Studies; D012457:Salicylamides / Q000378:metabolism*; D012680:Sensitivity and Specificity
D008024:Ligands; D017448:Receptors, Dopamine D2; D050637:Receptors, Dopamine D3; D012457:Salicylamides; C100958:desmethoxyfallypride