Incorporation of Brain Connectomics for Stereotactic Radiosurgery Treatment Planning

Neurosurgeons have integrated neuroanatomy-based tractography to avoid critical structures during dose planning. However, they have yet to integrate more comprehensive connectome networks for radiosurgical planning.

A young man presented with a Spetzler-Martin Grade 3 right temporal arteriovenous malformation.

As proof of concept, we incorporated connectomic networks including default mode network, optic radiation and central executive network into the Gamma Knife radiosurgical treatment planning workflow. Connectome networks were created from T1 anatomic and diffusion-weighted images magnetic resonance images using Quicktome software. The resulting networks were voxel-encoded in the magnetic resonance images, imported into GammaPlan, and segmented by image thresholding. The GammaPlan Lightning optimizer was used to create radiosurgical plans with a dose of 20 Gy to the 50% isodose line delivered to the arteriovenous malformation nidus both with and without treating these networks as risk structures. When taking into account the connectome networks, a maximum dose restriction of 14 Gy was placed on each network during lightning dose planning. With default mode network, optic radiation, and central executive network as risk structures, the maximum dose and V 12Gy were reduced by 23.4% and 88.3%, 20% and 34.3%, and 29.8% and 63.2%, respectively.

We were able to incorporate connectomes into radiosurgical dose planning approaches. This allowed for dose reductions to the networks while still achieving delivery of a therapeutic dose to the target volume.