Understanding gamma ventral capsulotomy: Potential implications of diffusion tensor image tractography on target...

Area of Science:

• Neurosurgery
• Neuroimaging
• Computational Neuroscience

Background:

• The utility of tractography in gamma ventral capsulotomy (GVC) planning remains under investigation.
• Understanding the spatial arrangement of orbitofrontal cortex (OFC) fibers within the anterior limb of the internal capsule (ALIC) is crucial for precise surgical targeting.

Purpose of the Study:

• To delineate the spatial distribution of medial and lateral OFC fibers traversing the ALIC.
• To identify quantitative tractography parameters that distinguish patients with obsessive-compulsive disorder (OCD) from those with Parkinson's disease (PD) or morbid obesity undergoing functional neurosurgery.

Main Methods:

• Diffusion tensor image tractography was performed on 20 patients (5 OCD, 9 PD, 6 morbid obesity) between 2013 and 2016.
• OCD patients underwent GVC, while PD and morbid obesity patients received deep brain stimulation implants.
• Tracts were reconstructed using Brainlab Elements software.

Main Results:

• Medial OFC fibers were consistently located inferior to lateral OFC fibers within the ALIC, though individual variations in topography were observed.
• Fiber tract volumes for both medial and lateral OFC were significantly lower in PD and morbid obesity patients compared to OCD patients.
• Patient demographics (age) differed significantly across the three groups (P < 0.001).

Conclusions:

• A general topographical standard for medial and lateral OFC fibers exists within the ALIC, with lateral OFC fibers positioned higher than medial OFC fibers.
• Quantitative tractography reveals significant differences in OFC fiber tract statistics among patients with OCD, PD, and morbid obesity, suggesting potential utility in surgical planning.