Multiple system atrophy and progressive supranuclear palsy. Diminished striatal D2 dopamine receptor activity demonstrated by 123I-IBZM single photon emission computed tomography.
OBJECTIVE
To measure D2 dopamine receptors in the striatum in patients with multiple system atrophy and progressive supranuclear palsy by I 3-iodo-6-methoxybenzamide labeled with iodine I 123 (123I-IBZM) single photon emission computed tomography and differentiate them from control subjects.


METHODS
Survey with the following as retrospective criterion standards: (1) parkinsonism, (2) negative apomorphine test, and (3) no or only slight reaction to dopaminergic medication.


METHODS
Ambulatory or hospitalized care in an academic referral center.


METHODS
Twenty-one patients with parkinsonism not responding to dopaminergic medication (17 with multiple system atrophy and four with progressive supranuclear palsy) and 21 control subjects without parkinsonism.


METHODS
In vivo imaging by single photon emission computed tomography using the D2 dopamine receptor specific radioligand 123I-IBZM.


METHODS
Striatum/occipital cortex ratio of count rate density as semiquantitative measurement for striatal D2 dopamine receptor density.


RESULTS
A highly significant loss of striatal uptake of 123I-IBZM was observed in the patients in comparison to the control subjects with little or no overlap between values.


CONCLUSIONS
The hypothesized loss of D2 receptors in multiple system atrophy has been confirmed. Use of 123I-IBZM single photon emission computed tomography may be a cost-effective alternative to positron emission tomography in the differential diagnosis of parkinsonism and in the selection of patients for dopaminergic therapy.
van Royen
E
E
Department of Nuclear Medicine, Academic Medical Centre, University of Amsterdam, The Netherlands.
Verhoeff
N F
NF
Speelman
J D
JD
Wolters
E C
EC
Kuiper
M A
MA
Janssen
A G
AG
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001284:Atrophy; D001549:Benzamides / Q000493:pharmacokinetics; D002490:Central Nervous System / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology*; D065127:Dopamine D2 Receptor Antagonists; D006801:Humans; D008875:Middle Aged; D010300:Parkinson Disease / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000378:metabolism; D011759:Pyrrolidines / Q000493:pharmacokinetics; D017448:Receptors, Dopamine D2 / Q000378:metabolism*; D013494:Supranuclear Palsy, Progressive / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000378:metabolism; D015899:Tomography, Emission-Computed, Single-Photon
D001549:Benzamides; D065127:Dopamine D2 Receptor Antagonists; D011759:Pyrrolidines; D017448:Receptors, Dopamine D2; C055743:3-iodo-2-hydroxy-6-methoxy-N-((1-ethyl-2-pyrrolidinyl)methyl)benzamide