Dopamine Transporter Imaging Predicts Mortality in a Long-Term Follow-Up after Subthalamic Deep Brain Stimulation in Parkinson's Disease.

INTRODUCTION

Deep brain stimulation of the subthalamic nucleus (STN-DBS) is an efficient treatment for advanced Parkinson's disease (PD), when oral medication no longer provides satisfactory symptom control or causes disabling side effects. However, long-term outcomes vary considerably, and reliable preoperative biomarkers remain lacking. Dopamine transporter single-photon emission computed tomography (DAT SPECT) provides an indirect in vivo measure of presynaptic striatal dopaminergic degeneration in the basal ganglia. In patients evaluated for STN-DBS, DAT SPECT with [123I]FP-CIT supported the clinical diagnosis. This study aimed to examine whether preoperative DAT SPECT predicts the long-term outcome after STN-DBS surgery.

METHODS

Fifty-five patients with PD underwent DAT SPECT before STN-DBS surgery. Motor symptoms were assessed in ON and OFF medication states before surgery, and at long-term follow-up, 8-14 years after surgery. Cognition was assessed before surgery and at the long-term follow-up, and clinical data were curated retrospectively from medical records.

RESULTS

Lower DAT striatal specific binding ratio (SBR) significantly correlated with longer disease duration, indicating greater dopaminergic loss. Reduced striatal SBR predicted increased mortality during the long-term follow-up. Regional analyses revealed that this association was driven by the caudate nucleus. Furthermore, greater caudate compared to putaminal involvement, reflected by a higher putaminal/caudate uptake ratio, was related to longer disease duration and increased mortality. Preoperative DAT SPECT measures were not associated with DBS effect, cognitive function, or depression.

CONCLUSION

Dopamine transporter imaging provides valuable insight into the pathophysiology and disease progression of PD. Although DAT SPECT did not predict the therapeutic effect of STN-DBS, this study demonstrates that DAT SPECT captures aspects of disease progression and survival in PD. These results highlight the value of assessing the dopaminergic system before advanced treatment, as DAT SPECT may provide prognostic indicators that could complement the preoperative evaluation.