The effect of levodopa therapy on dopamine transporter SPECT imaging with( 123)I-FP-CIT in patients with Parkinson's disease.
OBJECTIVE
The aim of this study was to evaluate, by means of (123)I-FP-CIT SPECT, the effect of chronic treatment with levodopa on striatal dopamine transporter (DAT) in patients with Parkinson's disease.


METHODS
Fifteen patients under stable levodopa/carbidopa monotherapy were imaged twice: at baseline on medication and after at least 20 days of treatment wash-out. DAT levels were assessed from SPECT imaging for the entire striatum, the right and left striatum, the right and left putamen and the right and left caudate, as a ratio of regional brain activities using the formula: (striatal region of interest-occipital)/occipital.


RESULTS
During levodopa wash-out, despite a worsening in patients' clinical disability (H&Y mean stage 2.53+/-0.58 versus 1.73+/-0.45 on therapy, p<0.001), striatal( 123)I-FP-CIT levels were not significantly different from those at baseline in any of the brain regions examined.


CONCLUSIONS
The results of this study suggest that levodopa does not affect( 123)I-FP-CIT brain imaging and confirm that it is not necessary to withdraw this medication to measure DAT levels with SPECT.
Schillaci
Orazio
O
Department of Biopathology and Diagnostic Imaging, University Tor Vergata, Rome, Italy. oschil@tiscalinet.it
Pierantozzi
Mariangela
M
Filippi
Luca
L
Manni
Carlo
C
Brusa
Livia
L
Danieli
Roberta
R
Bernardi
Giorgio
G
Simonetti
Giovanni
G
Stanzione
Paolo
P
D000368:Aged; D000978:Antiparkinson Agents / Q000008:administration & dosage; D016477:Artifacts; D001921:Brain / Q000000981:diagnostic imaging* / Q000187:drug effects / Q000378:metabolism*; D050483:Dopamine Plasma Membrane Transport Proteins / Q000378:metabolism*; D004347:Drug Interactions; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007980:Levodopa / Q000008:administration & dosage*; D008297:Male; D008657:Metabolic Clearance Rate / Q000187:drug effects; D008875:Middle Aged; D010300:Parkinson Disease / Q000000981:diagnostic imaging* / Q000188:drug therapy / Q000378:metabolism*; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods; D014326:Tropanes / Q000493:pharmacokinetics
D000978:Antiparkinson Agents; D050483:Dopamine Plasma Membrane Transport Proteins; D019275:Radiopharmaceuticals; D014326:Tropanes; C087552:2-carbomethoxy-8-(3-fluoropropyl)-3-(4-iodophenyl)tropane; D007980:Levodopa