One-day protocol for imaging of the nigrostriatal dopaminergic pathway in Parkinson's disease by [123I]FPCIT SPECT.
Parkinson's disease is characterized by degeneration of dopaminergic neurons, resulting in loss of dopamine transporters in the striatum. Recently, the tracer 1231-N-omega-fluoropropyl-2beta-carbomethoxy-3beta-(4-iodoph enyl)nortropane (FPCIT) was developed for imaging dopamine transporters with SPECT. The purpose of this study was to develop an [123I]FPCIT SPECT protocol for routine clinical studies.


METHODS
We examined the time course of [123I]FPCIT binding to dopamine transporters in 10 healthy volunteers and 19 patients with Parkinson's disease.


RESULTS
We found that the time of peak specific striatal [123I]FPCIT binding was highly varied among subjects, but specific binding peaked in all controls and patients within 3 h postinjection. Between 3 and 6 h, the ratio of specific-to-nonspecific striatal [123I]FPCIT binding was stable in both groups, although, as expected, it was significantly lower in patients. In the patients, [123I]FPCIT binding in the putamen was lower than in the caudate nucleus, and contralateral striatal binding was significantly lower than ipsilateral striatal binding. The subgroup of patients with hemi-Parkinson's disease showed loss of striatal dopamine transporters, even on the ipsilateral side.


CONCLUSIONS
For routine clinical [123I]FPCIT SPECT studies, we recommend imaging at a single time point, between 3 and 6 h postinjection, and using a tissue ratio as the outcome measure. The [123I]FPCIT SPECT technique is sensitive enough to distinguish control subjects from patients with Parkinson's disease, even at an early stage of the disease.
D001921:Brain / Q000000981:diagnostic imaging* / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism*; D016022:Case-Control Studies; D004298:Dopamine / Q000378:metabolism*; D050483:Dopamine Plasma Membrane Transport Proteins; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes; D008297:Male; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D008875:Middle Aged; D009419:Nerve Tissue Proteins; D009662:Nortropanes; D010300:Parkinson Disease / Q000000981:diagnostic imaging* / Q000378:metabolism; D019275:Radiopharmaceuticals; D013997:Time Factors; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D014326:Tropanes