A twenty-channel radio frequency coil for improved magnetic resonance imaging of the optic nerve

The purpose of this thesis was to design and construct a radio frequency (RF) coil array for imaging the optic nerve on a 3 Tesla magnetic resonance imaging (MRI) scanner. The goal of the work was to increase signal-to-noise ratio (SNR) from the eye orbits to the optic chiasm, compared to the SNR of a clinical 12-channel coil design used at our institution for imaging the optic nerve. The coil utilized a mask fiberglass former that allowed a good fit to many different head sizes. The new coil design used 20 channels arranged in a RF coil array, with coils positioned for optimal signal sensitivity along the length of the optic nerve. The 20-channel and commercially available coils were compared with one another based on the achievable SNR along the optic nerve pathway and on their parallel imaging capability. The Optic Nerve Coil provided 35% greater SNR at the optic chiasm and ∼300% near the orbit compared with the 12-channel commercial coil. The improved signal-to-noise ratio allowed for higher resolution diffusion tensor imaging, and the increased number of channels and their associated positions allowed for improved parallel imaging capability relative to the current 12-channel commercial coil. Patient images showed plaques in the images that correlated well with patient histories of bilateral and unilateral optic nerve disease. The new 20-channel coil has increased the diagnostic power of MRI for optic neuritis imaging.