A virtually 1H-free birdcage coil for zero echo time MRI without background signal

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Radiofrequency (RF) Coil Design
• Biophysics

Background:

• Zero echo time (ZTE) MRI enables efficient imaging of tissues with rapid transverse relaxation.
• High bandwidths in ZTE MRI can lead to artifacts from external radiofrequency (RF) signals, particularly from RF coils.
• Minimizing RF coil signal is crucial for reducing background artifacts in ZTE MRI.

Purpose of the Study:

• To design a birdcage RF coil that is virtually free of 1H signal for improved ZTE MRI.
• To overcome sensitivity to artifacts caused by external RF signals in high-bandwidth ZTE MRI.

Main Methods:

• Designed a transmit-receive birdcage RF coil for 7T MRI, specifically avoiding 1H-containing materials.
• Employed purely mechanical connections and ferromagnetic materials for signal spoiling.
• Tested the coil for residual 1H signal using ZTE phantom and in vivo joint imaging.

Main Results:

• No detectable 1H signal above noise level was observed in standard ZTE imaging.
• Negligible background artifacts were present in phantom images, even with extended dead times.
• High-quality ZTE MRI images of human joints were successfully acquired.

Conclusions:

• A virtually 1H-free birdcage coil enables ZTE MRI practically free of background signal.
• This coil design is effective even at high bandwidths, overcoming previous limitations.
• The developed coil significantly enhances the quality and reliability of ZTE MRI.