Snapshot whole-brain T₁ relaxometry using steady-state prepared spiral multislice variable flip angle imaging.

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Quantitative MRI
• Neuroimaging

Background:

• Variable flip angle (VFA) imaging is a standard for whole-brain T1 quantification.
• Conventional VFA relaxometry is time-consuming due to the need for multiple image acquisitions at different flip angles.

Purpose of the Study:

• To accelerate whole-brain T1 mapping at 1.5 Tesla using efficient spiral non-Cartesian imaging.
• To enable faster T1 quantification in the human brain.

Main Methods:

• Utilized radiofrequency spoiled gradient-echo imaging at two optimized flip angles.
• Employed an interleaved 2D multislice sequence with high spoiling efficiency.
• Accelerated acquisition using a spiral trajectory with 10 interleaves and dedicated magnetization preparation for rapid steady-state.

Main Results:

• Achieved whole-brain T1 maps at clinically relevant resolution in 40 seconds (0.7 s/slice) with high reproducibility.
• Successfully delineated white and gray matter T1 peaks using whole-brain T1 histograms.
• Demonstrated good agreement of T1 values with a reference method in selected regions of interest.

Conclusions:

• Fast spiral k-space trajectory significantly accelerates whole-brain VFA T1 mapping.
• Achieved an order-of-magnitude speed improvement compared to conventional Cartesian sampling.
• The developed method offers a clinically relevant and reproducible approach for rapid T1 quantification.