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T1 -corrected quantitative chemical shift-encoded MRI
Xiaoke Wang1,2, Timothy J Colgan1, Louis A Hinshaw1,2
1Department of Radiology, University of Wisconsin, Madison, Wisconsin.
Magnetic Resonance in Medicine
|November 15, 2019
Summary
A new MRI method improves liver fat quantification by correcting for T1 effects, reducing bias and enhancing accuracy. This variable flip angle-chemical-shift encoded MRI (VFA-CSE-MRI) shows promise for precise proton density fat-fraction (PDFF) measurements.
Area of Science:
- Medical Imaging
- Magnetic Resonance Imaging
- Quantitative MRI
Background:
- Proton density fat-fraction (PDFF) quantification is crucial for assessing liver conditions.
- Traditional chemical-shift encoded MRI (CSE-MRI) methods can be susceptible to noise and bias, particularly T1-related inaccuracies.
- Improving the accuracy and reliability of PDFF measurements is essential for clinical diagnosis and research.
Purpose of the Study:
- To develop and validate a T1-corrected CSE-MRI technique for improved PDFF quantification.
- To enhance noise performance and reduce bias in liver fat fraction measurements.
- To assess the feasibility of the new method in a clinical setting.
Main Methods:
- Development of a variable flip angle (VFA)-CSE-MRI method with joint-fit reconstruction.
- Evaluation using computer simulations and phantom experiments to investigate bias sources.
- Comparison of noise performance between VFA-CSE-MRI and low flip angle (LFA)-CSE-MRI.
- Prospective pilot study in patients undergoing liver MRI to quantify PDFF before and after contrast administration.
Main Results:
- VFA-CSE-MRI demonstrated accuracy and insensitivity to B1 inhomogeneities in simulations and phantoms.
- Joint-fit reconstruction eliminated T1-related bias and offered marginal noise improvement compared to LFA-CSE-MRI.
- Pilot study in 25 patients showed strong correlation and agreement between VFA-CSE-MRI and LFA-CSE-MRI PDFF measurements pre- and post-contrast.
- High R-squared values (0.97 and 0.93) and good agreement were observed in patient data.
Conclusions:
- Joint-fit VFA-CSE-MRI is a feasible method for T1-corrected PDFF quantification in the liver.
- The method is robust against B1 inhomogeneities and effectively eliminates T1 bias.
- While offering marginal SNR advantages for typical liver T1 values, it significantly improves quantitative accuracy.
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