Statistical Shape Analysis of Subthalamic Nucleus in Patients with Parkinson Disease

Subthalamic nucleus (STN) is the most targeted localization in the treatment of Parkinson disease (PD) with deep brain stimulation. However, no studies have been found in the literature about possible shape changes of STN in the literature. We aimed to investigate possible shape changes in the STN and the relationship between shape changes and disease duration in PD patients by using statistical analysis.

Patients who were diagnosed with idiopathic PD and controls were enrolled in this study. Age, sex, and disease duration of all cases were recorded. Turbo-spin-echo T2-weighted axial series parallel to the skull base in each case containing midbrain images were obtained, including the whole STN. Standard anatomic landmarks were selected and marked on each digital image using a special software in all cases. Statistical geometric shape and deformation analysis of STN was performed in 2 groups.

Forty-three patients with PD and 50 age/sex-matched controls were enrolled in this study. There were statistically significant left and right STN shape differences between the groups. Maximum deformation was seen in the dorsolateral parts of both STNs. General shape variability of the STNs was found on the left (0.096) and right (0.049).

Significant shape differences and remarkable deformation of STN are seen in patients with PD compared with controls. Maximum deformation was observed in the dorsolateral part of the STN, and with the increase in the duration of the PD, shape differences and deformations became more prominent.