Post-operative assessment in Deep Brain Stimulation based on multimodal images: registration workflow and validation

Abstract

ObjectMovement disorders in Parkinson disease patients may require functional surgery, when medical therapy isn't effective. In Deep Brain Stimulation (DBS) electrodes are implanted within the brain to stimulate deep structures such as SubThalamic Nucleus (STN). This paper describes successive steps for constructing a digital Atlas gathering patient's location of electrodes and contacts for post operative assessment. Materials and Method12 patients who had undergone bilateral STN DBS have participated to the study. Contacts on post-operative CT scans were automatically localized, based on black artefacts. For each patient, post operative CT images were rigidly registered to pre operative MR images. Then, pre operative MR images were registered to a MR template (super-resolution Collin27 average MRI template). This last registration was the combination of global affine, local affine and local non linear registrations, respectively. Four different studies were performed in order to validate the MR patient to template registration process, based on anatomical landmarks and clinical scores (i.e., Unified Parkinson's disease rating Scale). Visualisation software was developed for displaying into the template images the stimulated contacts represented as cylinders with a colour code related to the improvement of the UPDRS. ResultsThe automatic contact localization algorithm was successful for all the patients. Validation studies for the registration process gave a placement error of 1.4 +/-0.2 mm and coherence with UPDRS scores. ConclusionThe developed visualization tool allows post-operative assessment for previous interventions. Correlation with additional clinical scores will certainly permit to learn more about DBS and to better understand clinical side-effects.

Anatomo-clinical atlases correlate clinical data and electrode contact coordinates: Application to subthalamic deep brain stimulation

“…The proposed anatomo-clinical atlases were created to provide the A c c e p t e d M a n u s c r i p t 21 surgeons with additional assistance for better understanding of DBS-related phenomena. It could find its application in pre-operative planning (Dawant et al, 2007;Stancanello et al, 2008) as well as for postoperative assessment (Lalys et al, 2009). As targeting is mainly based on the surgeon's knowledge and experience, it could serve as an additional source of information obtained from retrospective studies for reducing time and predicting motor outcome and possible post-operative adverse-effects.…”

PyDBS: an automated image processing workflow for deep brain stimulation surgery

“…Atlas registration is performed over five processing steps (Fig. 5), including both linear and non-linear registrations and taking a similar global-to-local approach to the one previously described by Lalys et al [19]. Firstly, all non-brain voxels are masked out of both images, followed by rigid coregistration of both (six degrees of freedom [DOF]).…”

Construction and assessment of a 3-T MRI brain template

“…We studied the impact on patient-to-template image registration of our final template compared with the improved version of the Colin27 template (Aubert-Broche et al, 2006). We applied the same registration workflow to a set of 15 patients with idiopathic Parkinson's diseases (Lalys et al, 2009).…”

“…Our T1-T2 mixed template further improves contrast of basal ganglia, such as the subthalamic nucleus and the globus pallidus, which are targets of DBS in patients with movement disorder. Our templates would be useful in the preoperative workflow for improved DBS targeting (Stancanello et al, 2008;Dawant et al, 2007;Guo et al, 2005), as well for postoperative assessment (Lalys et al, 2009). Such high-resolution low-noise templates could also be used to evaluate and improve atlas-based image processing methods, such as segmentation (Scherrer el al., 2008;Pohl et al, 2006).…”