Introduction: The role of tractography in Gamma Ventral Capsulotomy (GVC) planning is still unclear. This paper aims to describe the spatial distribution of medial OFC and lateral OFC fibers passing through anterior internal capsule and analyze quantitative tractography parameters that differentiate Obsessive-Compulsive Disorder (OCD) individuals from other functional patients
Methods: Twenty patients undergoing functional stereotactic procedures, between 2013 and 2016 were included in this study. Obsessive-compulsive disorders (OCD) patients underwent GVC (single shot 150 Gy and 4mm collimators). Parkinson’s disease (PD) and Morbid Obesity patients were submitted to deep brain stimulation (DBS) implants in the subthalamic nucleus, pallidum internum, or hypothalamus. Diffusion tensor image (DTI) tractography was reconstructed using Brainlab Elements software (Brainlab AG, Feldkirchen, Germany). Deterministic fiber tracking (fractional anisotropy=0.15, minimum fiber length=50 mm, maximal angulation=13) was used in all cases to reconstruct fibers from OFC.
Results: Nine Parkinson disease, six morbid obesity, and five OCD patients were included with a mean age of, respectively, 65.4 9.1, 41.0 8.2 and 31.2 5.5, which are statistically different from each other (p<0,001). Fourteen patients (70%) were men. A total of 40 cerebral hemispheres were analyzed. Medial OFC fibers are localized more inferior in the AIC than the lateral OFC fibers in all hemispheres, but the level of intersection and exact topography of fiber bundles are variable among individuals. Both medial and lateral OFC fiber tracts of Parkinson disease and morbid obesity patients have lower volume than, respectively, medial and lateral counterparts of OCD patients (p<0,001).
Conclusions: Medial and lateral OFC tract fibers have a general standard distribution in anterior internal capsule (lateral OFC higher than medial OFC fibers).
Patient Care: We could improve results of GVC based on fiber tracking singularities
Learning Objectives: There are differences between obesity, Parkinson and OCD patients regarding fiber tracts statistics, what could support OCD fiber tracking singularities that justify additional studies trying to identify specific targets based on DTI tractography.