Clinical Scorecard: Utilizing Functional Magnetic Resonance Imaging (fMRI) to Enhance Planning of Laser Interstitial Thermal Therapy (LITT) Near Critical Brain Areas

At a Glance

Key Highlights

• fMRI enables precise localization and lateralization of functional language and motor areas relative to lesions to guide LITT trajectory planning.
• Use of fMRI-validated cortical functional regions as seeds for tractography improves delineation of eloquent cortex and subcortical tracts.
• Intraoperative temperature safety points based on fMRI data help maintain safe ablation margins and reduce postoperative neurological deficits.

Guideline-Based Recommendations

Diagnosis

• Perform preoperative fMRI including multiple language tasks and motor mapping to lateralize and localize functional areas near lesions.
• Use high-resolution MRI and diffusion tensor imaging (DTI) for anatomical and tractographic correlation with fMRI activation maps.

Management

• Incorporate fMRI data into surgical navigation software (e.g., BrainLAB) for trajectory planning and intraoperative guidance during LITT.
• Plan LITT trajectories to avoid fMRI-identified eloquent cortex and critical subcortical tracts, adjusting approach based on functional mapping.
• Consider alternative surgical approaches (e.g., open resection with mapping) if fMRI shows lesion involvement of critical functional areas.

Monitoring & Follow-up

• Use intraoperative MRI thermography with safety points derived from fMRI to monitor ablation and prevent thermal injury to eloquent regions.
• Confirm probe positioning with intraoperative imaging before ablation and adjust as needed based on real-time feedback.

Risks

• Potential for unintended thermal damage to adjacent normal brain tissue causing postoperative motor or language deficits.
• Limitations in cortical or subcortical mapping during ablation due to physiologic movement affecting targeting accuracy.
• Increased patient discomfort and cost associated with awake neurologic assessment or immobilization adjuncts.

Patient & Prescribing Data

Patients with intracranial lesions near eloquent brain areas undergoing evaluation for LITT

fMRI-guided planning can identify patients unsuitable for LITT due to high risk of functional deficits, guiding alternative treatment decisions

Clinical Best Practices

• Integrate multi-task fMRI language and motor paradigms to robustly identify functional cortical areas preoperatively.
• Overlay fMRI activation maps onto anatomical MRI and DTI images for comprehensive surgical planning.
• Use fMRI-validated functional seeds for deterministic tractography to delineate critical white matter tracts.
• Employ stereotactic registration with fiducials or intraoperative CT to enhance targeting accuracy.
• Apply intraoperative MRI thermography with fMRI-derived safety margins to monitor ablation and protect eloquent cortex.
• Review fMRI data collaboratively with neurosurgeons and neuroradiologists to optimize trajectory and treatment decisions.

References

• Laser interstitial thermal therapy (LITT) efficacy and indications
• fMRI language mapping methods
• BrainLAB surgical navigation system
• Monteris NeuroBlate system for LITT