Bilateral orthogonality generative acquisitions method for homogeneous T 2 * images using parallel transmission at 7...

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Biomedical Engineering

Background:

• Transmit field inhomogeneity is a major challenge in high-field MRI, particularly at 7T.
• Existing methods struggle to achieve uniform $$ contrast, especially in specific image regions.

Purpose of the Study:

• To develop a novel method for generating homogeneous $$ images using parallel-transmission (pTx) systems at 7T.
• To overcome the limitations of transmit field inhomogeneity in MRI acquisitions.

Main Methods:

• Introduced a bilateral orthogonality generative acquisitions method utilizing four low-angle gradient-echo (GRE) acquisitions.
• Acquired images in circularly polarized mode and a modified mode with a phase shift, alongside single-channel acquisitions.
• Demonstrated the method in dual-channel and eight-channel pTx systems with phantom and in vivo whole-brain experiments.

Main Results:

• The novel method produced more homogeneous $$ contrast compared to existing techniques.
• Improvements were particularly notable in low-intensity regions of circularly polarized-mode images.

Conclusions:

• The developed method is easy to implement and robust for generating homogeneous $$ images.
• It is effective across pTx systems with varying channel numbers, outperforming ratio of two GRE acquisitions and TIAMO methods.