Coil optimization for low-field MRI: a dedicated process for small animal preclinical studies

Area of Science:

• Biomedical Engineering
• Medical Imaging

Background:

• Accurate quantification of small biological volumes is crucial for preclinical research.
• Existing magnetic resonance imaging (MRI) coils often lack the sensitivity for small-volume analysis, especially on low-field systems.

Purpose of the Study:

• To develop and validate a method for fast in vivo quantification of small volumes (down to 25 µL) using optimized low-field MRI coils.
• To enhance the signal-to-noise ratio (SNR) for improved imaging of small biological samples.

Main Methods:

• Developed an analytical model to optimize MRI coil design for maximum SNR based on object size and shape.
• Designed and characterized custom low-field MRI coils using saline phantoms to validate the model.
• Applied the optimized coils for in vivo quantification of intradermal gel injections in rabbits and imaging intervertebral disks in rat tails.

Main Results:

• The analytical model successfully guided the design of high-SNR MRI coils tailored for small volumes.
• Demonstrated feasibility of quantifying ~200 µL intradermal gel in rabbits and imaging rat tail intervertebral disks.
• Achieved high-quality imaging results not possible with standard commercial coils on the available low-field MRI system.

Conclusions:

• The developed coil optimization method enables fast, accurate small-volume quantification using low-field MRI.
• This approach significantly expands the capabilities of low-cost preclinical research, offering new opportunities for in vivo studies.
• Optimized custom coils are essential for overcoming limitations of commercial coils in specialized small-volume MRI applications.