Deep brain stimulation (DBS) is used to reduce the motor symptoms such as rigidity or bradykinesia, in patients
with Parkinson's disease (PD). The Subthalamic Nucleus (STN) has emerged as prime target of DBS in idiopathic PD.
However, DBS surgery is a difficult procedure requiring the exact positioning of electrodes in the pre-operative selected
targets. This positioning is usually planned using patients' pre-operative images, along with digital atlases, assuming that
electrode's trajectory is linear. However, it has been demonstrated that anatomical brain deformations induce electrode's
deformations resulting in errors in the intra-operative targeting stage. In order to meet the need of a higher degree of
placement accuracy and to help constructing a computer-aided-placement tool, we studied the electrodes' deformation in
regards to patients' clinical data (i.e., sex, mean PD duration and brain atrophy index). Firstly, we presented an automatic
algorithm for the segmentation of electrode's axis from post-operative CT images, which aims to localize the electrodes'
stimulated contacts. To assess our method, we applied our algorithm on 25 patients who had undergone bilateral STNDBS.
We found a placement error of 0.91±0.38 mm. Then, from the segmented axis, we quantitatively analyzed the
electrodes' curvature and correlated it with patients' clinical data. We found a positive significant correlation between
mean curvature index of the electrode and brain atrophy index for male patients and between mean curvature index of the
electrode and mean PD duration for female patients. These results help understanding DBS electrode' deformations and
would help ensuring better anticipation of electrodes' placement.