Automated Optimization of Subcortical Cerebral MR Imaging−Atlas Coregistration for Improved Postoperative Electrode Localization in Deep Brain Stimulation

Abstract

BACKGROUND AND PURPOSE:The efficacy of deep brain stimulation in treating movement disorders depends critically on electrode localization, which is conventionally described by using coordinates relative to the midcommissural point. This approach requires manual measurement and lacks spatial normalization of anatomic variances. Normalization is based on intersubject spatial alignment (coregistration) of corresponding brain structures by using different geometric transformations. Here, we have devised and evaluated a scheme for automated subcortical optimization of coregistration (ASOC), which maximizes patient-to-atlas normalization accuracy of postoperative structural MR imaging into the standard Montreal Neurologic Institute (MNI) space for the basal ganglia.

Stimulation sites in the subthalamic nucleus projected onto a mean 3-D atlas of the thalamus and basal ganglia

“…The hypointense zone in MRI does not tightly correspond to the STN [12,19] [14,18,20,23]. Our finding of the median of the optimal stimulation sites in the dorso-lateral STN agrees with reports that stimulation in the dorso-lateral STN [5,22] improves motor symptoms in PD patients.…”

Scaling of Movement Is Related to Pallidal γ Oscillations in Patients with Dystonia

“…Correct placement of the DBS electrode was confirmed by intraoperative microelectrode recordings and direct macrostimulation in all patients. Moreover, localization of DBS electrodes was verified by postoperative MRI (Berlin) or stereotactic CT (Hannover) imaging using automated normalization and contact localization in standard Montreal Neurological Institute (MNI) stereotactic space coordinates [methods are described in more detail in the study by Schönecker et al (2009)] in all patients (except for case 16 and 22 where image quality of postoperative CT was not sufficient). Evaluation of clinical efficacy of chronic DBS on motor symptoms revealed an overall mean improvement of 46.5% [using TWSTRS (Toronto Western spasmodic torticollis rating scale, case 1-8 and 10 -22) and BFMDRS (Burke-Fahn-Marsden dystonia rating scale, case 9) at least 3 months after DBS surgery], which further supported correct placement of DBS electrodes in our patients.…”

Functional and effective connectivity in subthalamic local field potential recordings of patients with Parkinson’s disease

“…Notably, despite this careful electrode selection, and because of the limited accuracy of the post-operative imaging method in the average range of 1-2 mm (Scho¨necker et al, 2009), one cannot exclude the possibility of detecting neuronal interactions also in the very close vicinity of STN (e.g., zona incerta). However, the use of such small bipolar derivations allows studying connectivity between local sources primarily within STN.…”

“…For the analysis of connectivity, the bipolar channels were grouped into pairs, with three channel pairs for the connections in each STN (left STN: L01-12, L12-23, and L01-23; right STN: R01-12, R12-23, and R01-23). Notably, in comparison to other studies of connectivity involving STN (e.g., Klostermann et al, 2007;de Solages et al, 2010;Hirschmann et al, 2011;Litvak et al, 2011) an advantage of the present study is that we used an anatomical reconstruction of the electrode trajectory (Scho¨necker et al, 2009) for analyzing only those bipolar channels with at least one contact in STN (see Hohlefeld et al, 2012, for details and for the justification of including contact pairs in the analysis). The present selection approach ensures that if in a given bipolar channel (e.g., channel 23) both contacts were outside of STN (for channel 23 this would mean that the dorsal end of the electrode track being out of STN), then this channel was excluded and no coherence was calculated between this channel and others.…”