[(123)I]beta-CIT SPECT is a useful method for monitoring dopaminergic degeneration in early stage Parkinson's disease.
OBJECTIVE
To examine the validity of [(123)I]beta-CIT SPECT for monitoring the progression of dopaminergic degeneration in Parkinson's disease; to investigate the influence of short term treatment with D(2)receptor agonists on striatal [(123)I]beta-CIT binding; and to determine the sample size and frequency of SPECT imaging required to demonstrate a significant effect of a putative neuroprotective agent.


METHODS
A group of 50 early stage Parkinson's disease patients was examined. Two SPECT imaging series were obtained, 12 months apart. The mean annual change in the ratio of specific to non-specific [(123)I]beta-CIT binding to the striatum, putamen, and caudate nucleus was used as the outcome measure.


RESULTS
A decrease in [(123)I]beta-CIT binding ratios between the two images was found in all regions of interest. The average decrease in [(123)I]beta-CIT binding ratios was about 8% in the whole striatum, 8% in the putaminal region, and 4% in the caudate region. Comparison of scans done in nine patients under two different conditions-in the off state and while on drug treatment-showed no significant alterations in the expression of striatal dopamine transporters as measured using [(123)I]beta-CIT SPECT. Power analysis indicated that to detect a significant (p < 0.05) effect of a neuroprotective agent with 0.80 power and 30% of predicted protection within two years, 216 patients are required in each group when the effects are measured in the whole putamen.


CONCLUSIONS
[(123)I]beta-CIT SPECT seems to be a useful tool to investigate the progression of dopaminergic degeneration in Parkinson's disease and may provide an objective method of measuring the effectiveness of neuroprotective treatments. Short term treatment with a D(2)agonist does not have a significant influence on [(123)I]beta-CIT binding to dopamine transporters. If the latter finding is replicated in larger groups of patients, it supports the suitability of [(123)I]beta-CIT SPECT for examining the progression of neurodegeneration in patients being treated with D(2)receptor agonists.
Winogrodzka
A
A
Department of Neurology, Vrije Universiteit Medical Centre, The Netherlands. a.winogrodzka@vumc.nl
Bergmans
P
P
Booij
J
J
van Royen
E A
EA
Stoof
J C
JC
Wolters
E C
EC
D000978:Antiparkinson Agents / Q000627:therapeutic use; D052160:Benzothiazoles; D002421:Caudate Nucleus / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology; D003042:Cocaine / Q000031:analogs & derivatives*; D003342:Corpus Striatum / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology; D018450:Disease Progression; D005260:Female; D006801:Humans; D008297:Male; D009410:Nerve Degeneration / Q000473:pathology*; D010300:Parkinson Disease / Q000000981:diagnostic imaging* / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology*; D010479:Pergolide / Q000627:therapeutic use; D000077487:Pramipexole; D011699:Putamen / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology; D019275:Radiopharmaceuticals; D017448:Receptors, Dopamine D2 / Q000378:metabolism; D015203:Reproducibility of Results; D013844:Thiazoles / Q000627:therapeutic use; D015899:Tomography, Emission-Computed, Single-Photon; D016896:Treatment Outcome
D000978:Antiparkinson Agents; D052160:Benzothiazoles; D019275:Radiopharmaceuticals; D017448:Receptors, Dopamine D2; D013844:Thiazoles; D010479:Pergolide; C069723:2beta-carbomethoxy-3beta-(4-iodophenyl)tropane; D000077487:Pramipexole; D003042:Cocaine