CT-based MRI distortion correction reveals systematic coordinate discrepancies in subthalamic nucleus deep brain...

Area of Science:

• Neurosurgery
• Medical Imaging
• Neurology

Background:

• Accurate subthalamic nucleus (STN) targeting is crucial for deep brain stimulation (DBS) efficacy.
• Magnetic resonance imaging (MRI) geometric fidelity is essential for precise STN targeting.
• The impact of MRI distortion correction on STN coordinates is not well understood.

Purpose of the Study:

• To evaluate if CT-based MRI distortion correction systematically alters anatomically defined STN target coordinates.
• To quantify the shifts in STN coordinates resulting from MRI distortion correction.

Main Methods:

• Retrospective analysis of 30 adult patients with normal intracranial imaging.
• Acquisition of 1-mm axial T2-weighted MRI and 1-mm brain CT scans.
• Identification of bilateral STN targets on corrected and uncorrected MRI datasets by blinded raters.

Main Results:

• Mean Euclidean distance between corrected and uncorrected STN coordinates was 1.655 mm, exceeding the 1.0 mm threshold in all patients.
• Significant shifts observed primarily along lateral (X) and anteroposterior (Y) axes.
• Consistent directional displacement of uncorrected targets (lateral, posterior, inferior) relative to corrected targets.

Conclusions:

• CT-based MRI distortion correction induces substantial and systematic shifts in STN target coordinates.
• Corrected and uncorrected MRI workflows are not interchangeable for STN DBS planning.
• This highlights the need for careful consideration of distortion correction in DBS targeting strategies.