Targeted radiofrequency field mapping using 3D reduced field-of-view-catalyzed double-angle method

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Medical Physics
• Biomedical Engineering

Background:

• Accurate radiofrequency field (B(1)(+)) mapping is crucial for quantitative MRI.
• Existing methods often lack spatial specificity, limiting analysis to specific regions of interest.
• Developing targeted mapping techniques can improve precision in B(1)(+) assessment.

Purpose of the Study:

• To develop a targeted volumetric radiofrequency field (B(1)(+)) mapping technique.
• To provide region-of-interest specific B(1)(+) information.
• To enable precise B(1)(+) measurements in localized areas.

Main Methods:

• Utilized a three-dimensional (3D) reduced field-of-view (FOV) inner-volume turbo spin echo-catalyzed double-angle method (DAM).
• Acquired targeted B(1)(+) maps and compared them with full-FOV maps in phantoms and human subjects.
• Demonstrated targeted volumetric abdominal B(1)(+) mapping in a healthy volunteer.

Main Results:

• Targeted reduced-FOV images showed no aliasing artifacts.
• High correlation between targeted and full-FOV B(1)(+) maps, with minimal root-mean-squared error (<0.4% in phantom, <0.8% in brain).
• Abdominal B(1)(+) maps revealed minor variations in the kidneys and liver.

Conclusions:

• The proposed 3D reduced-FOV catalyzed DAM is a rapid, simple, and accurate method for targeted volumetric B(1)(+) mapping.
• This technique is easily implementable for RF field mapping in small, targeted regions.
• Offers potential for improved quantitative MRI analysis in specific anatomical areas.