Simulated field maps for susceptibility artefact correction in interventional MRI

Area of Science:

• Medical Imaging
• Neurosurgery
• Image Processing

Background:

• Intraoperative MRI (iMRI) aids precise image-guided neurosurgery.
• Diffusion-weighted MRI (DW-MRI) is crucial for nerve tract visualization but suffers from susceptibility artifacts near air-tissue boundaries.
• Existing artifact correction methods using field maps are challenging, especially with historical data.

Purpose of the Study:

• To present and validate a method for simulating magnetic field maps from structural MRI scans.
• To assess the effectiveness of simulated field maps in correcting DW-MRI susceptibility artifacts.
• To improve image quality for neurosurgical applications.

Main Methods:

• Automatic air-tissue segmentation of iMRI scans.
• Simulation of magnetic field maps using segmented structural MRI data.
• Application of both acquired and simulated field maps for DW-MRI artifact correction.

Main Results:

• Close agreement observed between acquired and simulated field maps.
• Statistically significant reduction in susceptibility artifacts in DW-MRI data corrected with simulated field maps near the resection.
• Acquired field maps provided superior artifact reduction across all brain regions evaluated.

Conclusions:

• Simulated field maps effectively reduce susceptibility artifacts, particularly near surgical resection sites.
• Accurate air-tissue segmentation is critical for successful field map simulation.
• The simulation technique is adaptable for various iMRI and neurosurgical procedures.