A novel topical probe for MRI: the flat, truncated line probe

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Radiofrequency (RF) Probe Design

Background:

• Conventional loop surface probes in MRI have limitations in B1 field direction and RF fringe electric field shielding.
• Achieving local homogeneity and impedance matching with traditional probes can be challenging.

Purpose of the Study:

• To describe the construction and imaging characteristics of novel flat, truncated line probes (FTLPs).
• To compare the performance of FTLPs against conventional loop surface probes.

Main Methods:

• Construction of FTLPs with a flattened, single-loop design and specific conductor dimensions.
• Evaluation of B1 field direction, RF fringe electric field shielding, local homogeneity adjustment, and impedance matching capabilities.
• Signal-to-noise ratio (S/N) comparison with a commercial probe (Phillips R2) using phantoms and body imaging.

Main Results:

• FTLPs exhibit perpendicular B1 field direction and inherent RF fringe electric field shielding.
• Local homogeneity adjustment and impedance matching to RF line impedance are achievable.
• In phantom studies, FTLPs showed a 20% greater S/N at the surface but lower at 5 cm depth compared to the R2 probe.
• In body imaging, FTLPs demonstrated equal S/N at 5 cm depth and approximately double the surface S/N compared to the R2 probe.

Conclusions:

• FTLPs represent a novel design for local MRI probes with distinct advantages over conventional loop probes.
• The unique design of FTLPs allows for improved S/N performance, particularly at the surface during body imaging.
• FTLPs offer enhanced control over imaging parameters and reduced loading effects from lossy samples.