Atlas-based identification of targets for functional radiosurgery

Area of Science:

• Neurosurgery
• Medical Imaging
• Computational Neuroscience

Background:

• Functional brain disorders like Parkinson's disease, dystonia, and epilepsy often resist medical treatment, necessitating surgical interventions.
• Deep brain stimulation (DBS) and radiosurgery are key surgical approaches, targeting specific brain regions such as the subthalamic nucleus (STN), globus pallidus pars interna (GPi), and centromedian nucleus of the thalamus (CMN).
• Accurate targeting is crucial, but radiosurgery lacks electrophysiological confirmation, relying solely on anatomical MRI, posing a challenge for precise treatment planning.

Purpose of the Study:

• To develop and validate an atlas-based method for accurate identification of surgical targets in the brain for functional neurosurgery.
• To improve the precision of targeting for procedures like deep brain stimulation (DBS) and radiosurgery.
• To establish a reliable method for aligning neuroanatomical atlases with patient-specific imaging for treatment planning.

Main Methods:

• Utilized the Talairach and Tournoux atlas to identify coordinates for STN, GPi, and CMN, transforming them to the Montreal Neurological Institute (MNI) electronic atlas.
• Created binary masks for target nuclei and deformed the MNI atlas onto patient MRI-T1 scans using affine and nonrigid registration techniques.
• Calculated the minimum distance between implanted electrodes and target masks, validating the method by correlating this distance with clinical outcomes in ten DBS cases.

Main Results:

• The MNI atlas registration to patient space was successful in all cases, with registration errors below the critical 2mm threshold.
• A strong correlation was observed between electrode-mask distance and clinical outcomes: larger distances indicated poorer outcomes, while closer proximity predicted clinical improvement.
• The method demonstrated high accuracy, with successful registration and a clear link between precise targeting and positive patient results.

Conclusions:

• The proposed atlas-based method provides a valuable tool for accurate target identification in functional neurosurgery and radiosurgery.
• This technique enhances treatment planning by enabling precise localization of deep brain nuclei.
• The method's applicability extends to various functional treatments, offering a standardized approach to neurosurgical targeting.