Relationship between clinical features of Parkinson's disease and presynaptic dopamine transporter binding assessed with [123I]IPT and single-photon emission tomography

IPT [N-(3-iodopropen-2-yl)- 2beta-carbomethoxy-3beta-(4-chlorophenyl) tropane] is a new cocaine analogue which allows the presynaptic dopamine transporters to be imaged with single-photon emission tomography (SPET) as early as 1-2 h post injection. In the present study [123I]IPT SPET was performed in patients with Parkinson's disease (PD) to analyse the relationship between specific dopamine tansporter binding and clinical features of the disease. Twenty-six PD patients (Hoehn and Yahr stages I-IV, age range 40-79 years) and eight age-matched controls were studied. SPET imaging was performed 90-120 min after injection of 160-185 MBq [123I]IPT using a triple-head camera. For semiquantitative evaluation of specific [123I]IPT binding, ratios between caudate, putamen and background regions were calculated. Specific [123I]IPT uptake was significantly reduced in PD patients compared to controls. Most patients showed a marked asymmetry with a more pronounced decrease in [123I]IPT binding on the side contralateral to the predominant clinical findings. The putamen was always more affected than the caudate. [123I]IPT binding was significantly correlated with disease duration (r=-0.7, P