Sub-millisecond 2D MRI of the vocal fold oscillation using single-point imaging with rapid encoding

Area of Science:

• Magnetic Resonance Imaging
• Biomedical Engineering
• Physiology

Background:

• Conventional MRI's slow spatial encoding limits its use for rapid physiological motion.
• Previous methods achieved high temporal resolution but were limited in encoding motion in multiple directions.

Purpose of the Study:

• To introduce a novel, fast MRI acquisition method.
• To demonstrate the feasibility of imaging rapid, two-dimensional vocal fold motion with sub-millisecond resolution.

Main Methods:

• Extended phase encoding to a second direction using single-point imaging with rapid encoding (SPIRE).
• Acquired 2D vocal fold oscillation data in the coronal view, gated by electroglottography (EGG).
• Used iterative reconstruction with total variation (TV) constraint and simulated the sequence with a motion phantom.

Main Results:

• Acquired dynamic images of vocal folds during phonation (150 and 165 Hz) in two volunteers.
• Achieved a temporal resolution of approximately 600 µs, visualizing periodic vocal fold motion.
• Simulations confirmed SPIRE's necessity for effective 2D motion encoding.

Conclusions:

• SPIRE is a novel MRI method capable of imaging rapidly oscillating structures.
• This technique provides the first dynamic images of vocal fold oscillations in the coronal plane.