Rapid single-scan T2*-mapping using exponential excitation pulses and image-based correction for linear background...

Area of Science:

• Magnetic Resonance Imaging
• Quantitative Imaging
• Biomedical Engineering

Background:

• Accurate T(2)* mapping is crucial for various MRI applications.
• Static magnetic field inhomogeneities introduce significant errors in T(2)* quantification.
• Existing methods often require long acquisition times or complex post-processing.

Purpose of the Study:

• To develop and validate a fast, quantitative T(2)* mapping method.
• To correct for static magnetic field inhomogeneities.
• To enable accurate T(2)* fitting with reduced acquisition time.

Main Methods:

• Utilized multiple gradient-echo (multi-GE) imaging with an exponential excitation pulse.
• Obtained field gradient maps from phase information for modulus data correction.
• Excluded data with significant signal loss due to field inhomogeneities.
• Applied additional correction for in-plane field gradients.

Main Results:

• Achieved accurate T(2)* values in phantom experiments up to 200 microT/m field gradients.
• Demonstrated errors not exceeding 15% for gradients up to 300 microT/m.
• Acquisition time was 15 seconds per slice for a 256x256 matrix, 1mm in-plane resolution, and 2mm slice thickness.
• In vivo T(2)* values at 3T showed excellent agreement with literature.

Conclusions:

• The developed method provides fast and accurate quantitative T(2)* mapping.
• Correction for magnetic field inhomogeneities significantly improves T(2)* quantification accuracy.
• This technique holds promise for efficient and reliable MRI-based tissue characterization.