Relationship between 123I-FP-CIT-SPECT and motor severity in drug-naive patients with Parkinson's disease

Although functional imaging is useful for the diagnosis and pathophysiological evaluation of Parkinson's disease (PD), little is known about the relationship between functional imaging findings and PD clinical features. The objective of this study was to determine the relationship between 123I-FP-CIT-SPECT findings and motor symptoms, in particular gait disturbance. The study included 46 drug-naive patients with early-stage PD. The specific binding ratios (SBRs) in the striatum and its subregions, namely anterior/posterior putamen and caudate nucleus, were calculated in patients who underwent 123I-FP-CIT-SPECT. Motor symptoms were evaluated using the modified Hoehn and Yahr (HY) stage and the Unified Parkinson's Disease Rating Scale (UPDRS) part III. Gait disturbance was evaluated by the mean gait cycle duration and the mean gait acceleration amplitude measured with a wearable sensor. The mean SBRs of the striatum and anterior putamen were significantly associated with the modified HY stage and UPDRS part III score. The mean SBR of the caudate nucleus was significantly associated with the UPDRS part III score. The mean striatal SBR was also significantly associated with the mean gait cycle duration and mean gait acceleration amplitude. The mean striatal SBR, as determined by 123I-FP-CIT-SPECT, was significantly associated with motor severity and gait severity in drug-naive patients with PD. •Striatal DAT binding correlates with motor severity in early-stage PD.•Striatal DAT binding correlates with gait disturbance in early-stage PD.•Possible floor effect should be considered when evaluating DAT binding.