Accelerated liver water T₁ mapping using single-shot continuous inversion-recovery spiral imaging

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Medical Physics
• Radiology

Background:

• Conventional liver T1 mapping techniques are limited by long breath-holds or scan times, susceptibility to B0 inhomogeneities, and complex signal processing.
• Accurate liver T1 quantification is crucial for diagnosing and monitoring various liver diseases.
• Existing methods often struggle with efficiency and robustness in clinical settings.

Purpose of the Study:

• To accelerate multi-slice liver water-selective T1 (wT1) mapping acquisition within a single breath hold.
• To enhance k-space sampling efficiency for improved T1 mapping.
• To develop a robust and repeatable liver wT1 mapping technique.

Main Methods:

• A continuous inversion-recovery (IR) Look-Locker method combined with a single-shot gradient echo spiral readout and Dixon processing was developed.
• Sequence parameters were optimized for rapid acquisition at 3 Tesla.
• Simulations assessed the influence of fat, B0 inhomogeneities, and TE; validation was performed in phantoms, volunteers, and patients.

Main Results:

• The proposed method achieved a scan time of 1.2 seconds per slice, enabling nine-slice acquisition in an 11-second breath hold.
• Results demonstrated robustness to B0 inhomogeneities and good repeatability, outperforming the MOLLI method in agreement with MRS.
• Phantom and volunteer studies showed good agreement with MRS, and patient scans successfully visualized liver lesions, confirming clinical feasibility.

Conclusions:

• Rapid, repeatable, multi-slice liver water T1 mapping is achievable in a single breath hold using a continuous IR Look-Locker method with spiral acquisition.
• The technique eliminates the need for a B0 map, simplifying the process.
• This method is suitable for clinical applications requiring efficient and accurate liver T1 quantification.