Optimized gradient spoiling of UTE VFA-AFI sequences for robust T₁ estimation with B₁-field correction

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Biomedical Engineering
• Medical Physics

Background:

• Accurate T1 relaxation time quantification in MRI is hindered by B1 field inhomogeneities.
• Tissues with short T2* values present challenges for conventional MRI due to insufficient signal.
• Actual Flip angle Imaging (AFI) combined with ultra-short echo-time (UTE) sequences enables signal quantification in short T2* tissues.

Purpose of the Study:

• To develop an improved B1 field correction technique for MRI.
• To reduce the acquisition time required for accurate B1 mapping.
• To enhance the quantification of T1 relaxation times, especially in challenging tissues.

Main Methods:

• Proposed a novel spoiling scheme for the Actual Flip angle Imaging (AFI) sequence.
• Integrated the new spoiling scheme with ultra-short echo-time (UTE) MRI sequences.
• Validated the method using phantom studies and preliminary in vivo data.

Main Results:

• Achieved accurate B1 correction maps with a significantly reduced acquisition time.
• Demonstrated the effectiveness of the novel spoiling scheme in overcoming AFI's limitations.
• Showcased the potential for improved T1 quantification in tissues with short T2* values.

Conclusions:

• The novel AFI spoiling scheme offers efficient and accurate B1 correction.
• This method significantly reduces MRI acquisition time for B1 mapping.
• The technique holds promise for enhanced quantitative MRI in various clinical applications.