Comparison of multicenter MRI protocols for visualizing the spinal cord gray matter

Area of Science:

• Radiology and Medical Imaging
• Neuroimaging
• Biomedical Engineering

Background:

• Spinal cord gray-matter imaging is crucial for various clinical applications but presents significant technical challenges.
• Optimizing Magnetic Resonance Imaging (MRI) protocols is essential for enhancing the visualization of spinal cord gray matter.

Purpose of the Study:

• To compare the effectiveness of different MRI protocols at 1.5 Tesla (T), 3T, and 7T for visualizing spinal cord gray matter.
• To evaluate quantitative metrics for assessing image quality and contrast-to-noise ratio in spinal cord MRI.

Main Methods:

• Collected in vivo cervical spinal cord MRI data from nine centers across 1.5T, 3T, and 7T scanners.
• Developed automated segmentation and co-registration techniques, calculating signal-to-noise ratio (SNR) and white/gray matter contrast-to-noise ratio.
• Utilized synthetic phantom data for metric validation and conducted qualitative assessments by experienced radiologists on a large multicenter dataset (N=267).

Main Results:

• Qualitative image quality was comparable between 3T and 7T, with higher spatial resolution at increased field strengths.
• Image quality at 1.5T was generally moderate to low.
• Proposed quantitative metrics demonstrated robustness, though SNR_single showed limitations with partial-volume effects.

Conclusions:

• Established quality assessment criteria and quantitative metrics for spinal cord gray-matter visualization.
• The analyzed protocols and open-source code provide a benchmark for optimizing future spinal cord MRI protocols.
• 3T and 7T MRI protocols show superior performance for gray matter visualization compared to 1.5T.