Navigator readouts with optimized processing improve spinal cord and gray matter segmentability in multi-echo...

Area of Science:

• Medical Imaging
• Neuroimaging
• Magnetic Resonance Imaging (MRI)

Background:

• Multi-echo gradient-echo (ME-GRE) MRI of the spinal cord (SC) is prone to artifacts from breathing-induced magnetic field fluctuations.
• Conventional navigator processing methods are often ineffective for SC due to its unique anatomy and small size.

Purpose of the Study:

• To evaluate the impact of a novel SC-specific navigator processing technique on SC and gray matter (GM) segmentability in ME-GRE acquisitions.
• To assess improvements in image quality and segmentation performance using the optimized navigator correction.

Main Methods:

• ME-GRE MRI scans of the SC were acquired at 3T in ten volunteers, with and without a centerline navigator readout.
• A recently developed SC-specific method was used to process the navigator echo data.
• Image quality was assessed using contrast-to-noise ratio (CNR), qualitative segmentation ratings, and automatic segmentation algorithm performance.

Main Results:

• Optimized navigator correction significantly improved quantitative image quality, especially GM-white matter CNR at multiple SC levels.
• Qualitative assessments showed a preference for navigator-corrected images, particularly for GM segmentability in the lumbosacral region.
• Automatic GM segmentation remained robust with navigator correction, even in cases where uncorrected scans failed due to artifacts.

Conclusions:

• Navigator processing optimized for SC imaging enhances image quality and segmentability in ME-GRE acquisitions.
• This improved technique holds promise for both clinical diagnostics and research applications involving spinal cord imaging.