Imaging the Internal Auditory Canal with an 8 × 2 Transceiver Array Head Coil at 7T

Area of Science:

• Radiology
• Medical Imaging
• Neuroscience

Background:

• 7T neuroimaging faces challenges with B1+ strength, homogeneity, and B0 susceptibility, particularly in inferior brain regions.
• Standard imaging coils often struggle to provide adequate signal quality for detailed anatomical assessment in these areas.

Purpose of the Study:

• To evaluate the effectiveness of a decoupled 8x2 transceiver coil and shim insert for imaging the internal auditory canal (IAC) and inferior brain at 7T.
• To compare the performance of the new transceiver coil against the standard Nova 8/32 coil for specific neuroimaging applications.

Main Methods:

• Comparison of B1+ field strength, B0 susceptibility, and T2 sampling perfection with application-optimized contrasts by using flip angle evolution (SPACE) sequences.
• Acquisition of T2-weighted turbo spin echo (T2 TSE) images in 8 healthy adults using a Terra 7T system.
• Blind evaluation of IAC and surrounding structures by two neuroradiologists using a 5-point Likert scale.

Main Results:

• The standard Nova 8/32 coil exhibited reduced B1+ strength in inferior regions compared to the whole brain.
• The new transceiver coil maintained consistent B1+ performance across the entire brain, including inferior regions.
• SPACE images acquired with the transceiver coil showed significantly better performance, with higher scores for IAC visualization (4.0 ± 0.8) compared to the Nova coil (2.5 ± 0.8).

Conclusions:

• The decoupled 8x2 transceiver coil demonstrates superior B1+ performance in inferior brain regions at 7T.
• Improved B1+ homogeneity facilitates enhanced visualization of the IAC and other inferior brain structures using T2-weighted imaging.
• This technology advances the capability of 7T MRI for detailed anatomical assessment of challenging brain areas.