Memory Tract Sparing Using Diffusion Tensor Imaging in Radiation Planning of Primary Brain Tumors

Area of Science:

• Neuro-oncology
• Radiation Oncology
• Cognitive Neuroscience

Background:

• Radiation therapy (RT) is crucial for brain tumors but can cause cognitive decline, particularly affecting the hippocampus.
• Hippocampal avoidance whole-brain RT with memantine shows promise for preserving cognition in brain metastases patients.

Purpose of the Study:

• To assess the safety and dosimetric feasibility of integrating diffusion tensor imaging (DTI)-based memory fiber tract sparing into RT planning for primary brain tumors.
• To evaluate the potential of this technique to preserve cognitive function.

Main Methods:

• A prospective trial included patients with primary brain tumors undergoing RT.
• DTI was used to map memory white matter tracts, which were contoured with hippocampi in treatment planning software.
• Volumetric modulated arc therapy (VMAT) plans incorporated memory fiber dose constraints.

Main Results:

• Contouring of memory fibers and hippocampi was successful in 12 low-grade glioma patients.
• VMAT plans achieved dose constraints for memory fibers (average mean dose 10.1 Gy).
• Cognitive assessment scores (Montreal Cognitive Assessment) showed a trend towards preservation post-treatment (average change -0.7, P=0.07).

Conclusions:

• DTI-guided RT planning with VMAT can spare the hippocampus and associated white matter tracts.
• This approach shows potential for preserving cognitive function in brain tumor patients.
• Further validation in larger cohorts is warranted.