Acoustic noise-optimized VERSE pulses.

Area of Science:

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

Background:

• Variable-rate selective excitation (VERSE) RF pulses in MRI reduce RF power but can increase gradient noise.
• High-field MRI systems frequently employ VERSE techniques, exacerbating gradient noise issues.
• Acoustic resonance frequencies in gradient systems contribute to high sound pressure levels during MRI.

Purpose of the Study:

• To develop an algorithm for calculating VERSE pulse modulation from constant slice selection gradients.
• To minimize acoustic resonance frequencies and reduce sound pressure levels.
• To simultaneously decrease specific absorption rate (SAR) in MRI.

Main Methods:

• An algorithm was developed to compute VERSE pulse modulation.
• The algorithm avoids known acoustic resonance frequencies of the gradient system.
• The method was validated using four distinct slice-selective RF pulse shapes: Sinc, Gaussian, and two Shinnar-LeRoux pulses.

Main Results:

• Sound measurements demonstrated a reduction in mean sound pressure level by up to 13 dB.
• Specific absorption rate (SAR) was reduced by 55% concurrently.
• The algorithm effectively modulated RF pulses while mitigating acoustic noise and RF power.

Conclusions:

• The presented algorithm offers an effective strategy for reducing acoustic noise and RF power in MRI.
• This technique enhances patient comfort and safety in high-field MRI environments.
• The findings suggest a significant improvement in MRI operational efficiency and patient experience.