Rapid high-resolution T₁ mapping using a highly accelerated radial steady-state free-precession technique

Area of Science:

• Magnetic Resonance Imaging
• Medical Physics
• Biomedical Engineering

Background:

• T1 mapping is crucial in clinical MRI protocols but often limited by slice coverage, resolution, or acquisition time.
• Existing T1 mapping techniques face challenges in balancing speed, resolution, and coverage.
• A novel approach is needed to overcome these limitations for efficient clinical application.

Purpose of the Study:

• To develop and validate a fast, multi-slice, high-resolution T1 mapping technique.
• To address the limitations of current T1 mapping methods in terms of speed and spatial resolution.
• To enable more comprehensive and efficient T1-weighted imaging in clinical settings.

Main Methods:

• A multi-slice inversion-recovery radial steady-state free precession (IR-radSSFP) pulse sequence was developed and implemented at 3T.
• Principal component (PC) based reconstruction was employed to enhance image quality and resolution.
• The technique was evaluated using computer simulations, phantom studies, and in vivo imaging of healthy volunteers and patients.

Main Results:

• Computer simulations optimized the flip angle to 20° for accurate T1 estimation.
• In vivo imaging achieved high spatial resolutions (e.g., 0.69x0.69x2.00 mm in brain, 0.83x0.83x3.00 mm in abdomen).
• The technique generated 84 brain slices in 3 minutes and 10 abdominal slices in a single breath-hold, with repeatable T1 values (1.7-2.7% coefficient of variation).

Conclusions:

• The multi-slice IR-radSSFP technique combined with PC reconstruction enables fast, high-resolution T1 mapping.
• This method overcomes previous limitations in slice coverage and acquisition time.
• The demonstrated technique is motion-insensitive and yields repeatable T1 values comparable to literature, showing significant potential for clinical use.