Accelerated DESPOT1 with variable parameters for 3D T1 brain mapping

Area of Science:

• Magnetic Resonance Imaging
• Quantitative MRI
• Biomedical Engineering

Background:

• Driven equilibrium single pulse observation of T1 (DESPOT1) is a standard for clinical 3D T1 brain mapping.
• Conventional DESPOT1 protocols are inefficient due to fixed parameters and linear modeling, limiting acquisition speed.

Purpose of the Study:

• To introduce a variable DESPOT1 (vDESPOT1) acquisition and modeling strategy.
• To improve scan efficiency and accelerate 3D T1 brain mapping acquisition.

Main Methods:

• vDESPOT1 employs SPGR acquisitions with optimized TRs, BWs, and FAs.
• Dictionary-based reconstruction is utilized for faster T1 mapping.
• The vDESPOT1 method was validated against DESPOT1 and IR-SE in phantoms and human subjects.

Main Results:

• vDESPOT1 achieved a ~40% reduction in scan time compared to conventional DESPOT1.
• Reconstruction time was reduced by approximately 50x due to dictionary-based methods.
• Variable bandwidth (BW) improved efficiency without significantly impacting T1 signal-to-noise ratio (SNR).

Conclusions:

• vDESPOT1 offers significant time improvements for 3D brain T1 mapping.
• The technique is valuable for dynamic MRI applications, including thermal therapy monitoring and DCE-MRI.
• vDESPOT1 is suitable for imaging in anatomies prone to motion, such as the heart, liver, and lungs.