Accelerated B 1 + $$ {\mathrm{B}}_1^{+} $$ mapping and robust parallel transmit pulse design for heart and prostate...

Area of Science:

• Medical Imaging
• Magnetic Resonance Imaging (MRI)

Background:

• Parallel transmit (pTx) technology enhances MRI performance.
• Optimizing RF pulse design is crucial for image quality and efficiency.

Purpose of the Study:

• To assess the impact of reduced k-space sampling on $$ mapping.
• To evaluate the effect on phase shimming and dynamic/universal parallel transmit (pTx) RF pulse design at 7 Tesla.

Main Methods:

• Channel-wise 3D $$ maps were acquired in healthy subjects for cardiac and prostate regions.
• Universal and individual phase shims and 4kT-point pulses were designed using accelerated $$ maps.
• Performance was evaluated based on coefficients of variation (CoV), $$ efficiencies, and specific energy doses (SED).

Main Results:

• Universal phase shims improved homogeneity and $$ efficiency compared to default shims.
• Individual phase shims based on accelerated $$ maps further enhanced performance.
• Tailored 4kT-pulses using accelerated $$ maps significantly reduced CoVs and/or specific energy doses.

Conclusions:

• Accelerated $$ maps facilitate the design of tailored pTx pulses for cardiac and prostate imaging at 7T.
• This approach optimizes homogeneity, $$ efficiency, and specific energy dose beyond universal pulse designs.