A comparison of fMRI presurgical mapping techniques with intraoperative brain mapping-based validation

Area of Science:

• Neuroimaging
• Neurosurgery
• Medical Imaging

Background:

• Resting-state functional MRI (rsfMRI) offers a potential alternative to task-based fMRI (tbfMRI) for preoperative risk assessment and intraoperative guidance, especially in patients unable to perform tbfMRI.
• Direct electrical stimulation (DES) serves as the gold standard for intraoperative functional mapping, providing ground truth for comparing fMRI techniques.

Purpose of the Study:

• To compare the accuracy of tbfMRI, single-echo rsfMRI (sTE-rsfMRI), and multiecho rsfMRI (mTE-rsfMRI) for functional sensory-motor mapping.
• To evaluate the suitability of rsfMRI as a preoperative tool by comparing its mapping accuracy against tbfMRI using DES as the reference standard.

Main Methods:

• Investigated 16 preoperative patients undergoing sensory-motor mapping of hands and feet.
• Compared spatial accuracy of tbfMRI (voxel size 1.8x1.8x3.2 mm³), sTE-rsfMRI (2x2x2.2 mm³), and mTE-rsfMRI (3x3x3 mm³) against DES coordinates.
• Utilized general linear models for tbfMRI, seed-based analysis (SBA) for rsfMRI, and receiver-operating characteristic (ROC) curves to assess accuracy and agreement.

Main Results:

• All fMRI methods demonstrated comparable accuracy to DES at a 2 mm distance cutoff, with minor differences in unthresholded distances (~2 mm).
• sTE-rsfMRI showed slightly reduced accuracy compared to tbfMRI at a 3 mm cutoff, while mTE-rsfMRI also exhibited mildly worse performance.
• Relative accuracy differences between sTE-rsfMRI and mTE-rsfMRI were minor when using consistent distance cutoffs, with no significant differences found between fMRI methods in statistical models.

Conclusions:

• Seed-based analysis rsfMRI exhibits comparable accuracy to tbfMRI for functional sensory-motor mapping, indicating its potential utility for presurgical mapping.
• The findings suggest rsfMRI is a viable alternative for patients unable to undergo tbfMRI, though further investigation into sTE-rsfMRI and mTE-rsfMRI relative accuracy is warranted.
• Direct electrical stimulation response significantly influenced mapping outcomes, highlighting its critical role in validating fMRI-based presurgical assessments.