How to assess active contact coordinates in deep brain stimulation surgery? Comparison of three methods for determining the position of the active contact.

To date there is still no agreement in the literature on postoperative active contact coordinate (ACc) acquisition. The aim of the study is to test if the use of three methods commonly adopted in the literature for ACc acquisition (stereotactic X-rays (RXc), postoperative MRI (MRIc) and calculation of the expected ACc) for the same active contact (ACo) lead to significant differences. In our series of 176 ACo, mean euclidean distances were 1.2 +/- 0.3, 2.1 +/- 1.3, and 2.5 +/- 1.6 mm between MRIc and RXc, RXc and EXc, and MRIc and EXc, respectively. Statistically significant differences along the three axes were found. Our results indicate that final ACc depends on the method adopted to acquire them. MRI and X-rays lead to a similar ACc acquisition. The difference between the EXc and the direct visualization methods (X-rays and MRI) is significantly higher.