Combinatorial Anatomic and Functional Neural Tract Mapping for Stereotactic Radiosurgery Planning

Area of Science:

• Neurosurgery
• Radiology
• Medical Imaging

Background:

• Stereotactic radiosurgery (SRS) is a key treatment for brain metastases (BMs).
• Increased SRS use necessitates better methods to predict and manage radiation-induced neurologic toxicity.
• Factors like patient age, genetics, prior treatments, dose, volume, and location influence injury risk.

Purpose of the Study:

• To develop and validate a systematic approach for integrated risk assessment in SRS patients.
• To identify and quantify the proximity of target lesions to critical neural structures.
• To mitigate radiation-induced neurologic toxicity through precise risk evaluation.

Main Methods:

• Combined patient-specific imaging with a reference neuroanatomical/functional atlas.
• Validated lesion proximity to neural tracts using functional MRI (fMRI) and diffusion tensor imaging MRI (DTI-MRI).
• Estimated dose-volume exposure to critical tracts like the corticospinal tract (CST).

Main Results:

• Successfully identified proximity of a thalamic/midbrain metastasis to the corticospinal tract (CST).
• DTI-MRI validated the CST's location relative to the target lesion.
• Enabled estimation of CST dose-volume exposure for treatment planning.

Conclusions:

• Merging pretreatment MRI with neuroanatomical atlases and fMRI/DTI-MRI offers a valuable method for screening individual SRS patients for neural risks.
• This approach can enhance understanding of dose tolerances for various neural structures.
• Further studies with larger cohorts can refine risk assessment and treatment strategies.