Dopamine transporter imaging predicts motor responsiveness to levodopa challenge in patients with Parkinson's disease: A pilot study of DATSCAN for subthalamic deep brain stimulation

Imaging studies are necessary prior to subthalamic deep brain stimulation (STN-DBS). Dopamine transporter (DAT) imaging is a powerful tool for visualizing dopamine terminals in the striatum, but its usefulness in STN-DBS is unclear. Here, we retrospectively investigated the relationship between motor symptoms and the specific binding ratio (SBR) on DAT imaging in patients with Parkinson's disease (PD). We included 23 consecutive patients (9 female; 14 male) who were evaluated for DBS eligibility between October 2013 and October 2014 and subsequently received bilateral STN-DBS. Correlation and simple regression analyses were performed on SBR values and clinical parameters before and after surgery. SBR value was negatively correlated with Unified Parkinson's Disease Rating Scale (UPDRS) motor score in the "ON" state before surgery (rs=-0.637, p=0.001) and positively correlated with the reduction of the levodopa equivalent daily dose by surgery (r=0.422, p=0.045). A simple regression analysis revealed that SBR value was positively correlated with UPDRS motor score improvement after levodopa challenge before surgery (p=0.001, R2=0.423). DAT imaging may be useful in STN-DBS candidate selection and the identification of the therapeutic mechanism of STN-DBS in patients with advanced PD and motor symptom fluctuations.