Stretchable coil arrays: application to knee imaging under varying flexion angles

Area of Science:

• Medical Imaging
• Biomedical Engineering
• Materials Science

Background:

• Current Magnetic Resonance Imaging (MRI) receiver arrays require precise positioning for optimal image quality.
• Fitting standard coils to diverse patient anatomies, especially joints, presents challenges in achieving close contact and comfort.
• Geometric adjustability and ease of handling are crucial for high-density receiver arrays in MRI.

Purpose of the Study:

• To design and evaluate a stretchable MRI receiver coil array with enhanced geometric adaptability.
• To assess the impact of coil stretchability on signal-to-noise ratio (SNR) and imaging performance.
• To demonstrate the utility of stretchable coils for in vivo imaging of complex anatomies like the human knee.

Main Methods:

• Constructed stretchable coil arrays using braided wire conductors on an elastic textile substrate.
• Conducted MRI experiments at 3 Tesla (T) to measure SNR yield.
• Investigated the SNR effects of coil stretching, with and without preamplifier matching adjustments.
• Evaluated four- and eight-channel arrays in phantoms and for in vivo knee imaging.

Main Results:

• Stretchable coil arrays automatically conform to anatomical shapes, ensuring close coupling.
• MRI experiments demonstrated high signal-to-noise ratio (SNR) yield from the stretchable coils.
• In vivo knee imaging showed uniform coverage across varying flexion angles (up to 60°).

Conclusions:

• Stretchable MRI receiver coils offer significant geometric adjustability and patient comfort.
• The developed coils maintain high SNR and uniform image coverage during joint motion.
• This technology advances MRI capabilities for dynamic imaging of anatomies requiring close coil conformance.