Controlling Signal Artifact With Software Threshold Imaging for Magnetic Resonance-Guided Laser Interstitial Thermal...

Area of Science:

• Neurosurgery
• Medical Imaging
• Oncology

Background:

• Magnetic resonance-guided laser interstitial thermal therapy (MRgLITT) employs intraoperative temperature mapping for intracranial ablations.
• Signal artifact at the target site can impede visualization of temperature imaging and thermal damage estimates, hindering procedural decision-making.
• The causes and effects of this signal artifact are not fully understood, but software settings may contribute.

Purpose of the Study:

• To investigate the impact of MRgLITT software threshold settings on the generation of signal artifact during intracranial ablations.

Main Methods:

• Thermal data from 33 MRgLITT procedures using the Visualase MRI-guided Laser Ablation System were reprocessed at varying threshold values (35-60).
• Artifact growth rates were analyzed in relation to threshold adjustments using linear regression.
• Correlations between artifact growth rates and laser power/duration were assessed using Pearson correlations.

Main Results:

• A significant increase in artifact area (13% per 1-point threshold increase) was observed in 28 of 33 patients (R2 > 0.99).
• Artifact growth rates did not correlate with laser power (r = 0.15) or duration (r = 0.0049).
• One artifact-free case developed artifact at a threshold of 60.

Conclusions:

• Signal artifact in MRgLITT appears multifactorial, influenced by both tissue properties and software configurations.
• Reducing software threshold values is a practical method for neurosurgeons to minimize procedure-related artifact.