Arcuate fasciculus tractography integrated into Gamma Knife surgery

Area of Science:

• Neurosurgery
• Radiation Oncology
• Medical Imaging

Background:

• Gamma Knife surgery (GKS) can cause speech disturbances.
• The arcuate fasciculus (AF) is crucial for speech production.
• Integrating AF tractography into GKS planning may mitigate speech deficits.

Purpose of the Study:

• To evaluate the efficacy of integrating arcuate fasciculus (AF) tractography into Gamma Knife surgery (GKS) treatment planning.
• To assess the relationship between radiation dose to the AF and the incidence of post-GKS speech disturbances.

Main Methods:

• Retrospective integration of AF tractography using diffusion tensor (DT) MR imaging into GKS planning for 12 patients with arteriovenous malformations near the AF.
• Coregistration of DT tractography and stereotactic 3D imaging data on a treatment planning workstation.
• Assessment of delivered radiation doses and posttreatment aphasia incidence.

Main Results:

• AF tractography was not feasible in 2 patients with pre-existing motor aphasia.
• Aphasia developed in 2 patients post-GKS: conduction aphasia with 30 Gy to frontal AF, motor aphasia with 9.6 Gy to temporal AF.
• No speech dysfunction observed with 10.0-16.8 Gy to frontal AF fibers and 3.6-5.2 Gy to temporal AF fibers.

Conclusions:

• A 10-Gy radiation dose to the frontal AF is tolerated during GKS, but not to the temporal AF.
• Integration of AF tractography is recommended for GKS planning, particularly for lesions near temporal language fibers.
• This approach can help minimize the risk of post-GKS speech disturbances.