PET examination of the monoamine transporter with [11c]β‐CIT and [11c]β‐CFT in early parkinson's disease

Abstract

The monoamine transporter was studied in 4 healthy controls and 5 patients with early Parkinson's disease (PD), who had not received any antiparkinsonian medication, by means of positron emission tomography (PET) using two novel ligands, [¹¹C]β-CIT and [¹¹C]β-CFT. Both ligands showed highest uptake in the striatum. There was intermediate accumulation of activity in the thalamus and midbrain, which was more marked for [¹¹C]β-CIT than for [¹¹C]β-CFT. In the cortical areas, uptake of both ligands was not different from that seen in the cerebellum. In the controls, the putamen-to-cerebellum and caudate-to-cerebellum ratios for [¹¹C]β-CFT were higher than those for [¹¹C]β-CIT (putamen: 3.15± 0.39 for [¹¹C]β-CFT, and 1.84 ±0.10 for [¹¹C]CIP-CIT caudate: 3.15±0.31 for [llC]P-CFT, and 1.95±0.17 for [¹¹C]β-CIT). Reduction from mean control value in PD patients was greater for [¹¹C]β-CFT (45% in the putamen contralateral to the predominant symptoms, P < 0.001) than for [¹¹C]β-CIT(20%, P > 0.05). [¹¹C]β-CFT uptake in the caudate nucleus was also diminished in PD patients (to 80% of the control mean, P < 0.05), whereas [¹¹C]β-CIT was within normal range (reduced to 90% of the control mean). These results indicate that both [¹¹C]β-CIT and [¹¹C]β-CFT are useful PET ligands to study brain monoamine transporter in healthy controls and in patients with PD. However, [¹¹C]β-CFT seems superior to [¹¹C]β-CIT in this respect.