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Quantitative Magnetic Resonance Imaging of Skeletal Muscle Disease
Published on: December 18, 2016
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Field inhomogeneity correction for qDESS mapping: application to rapid bilateral knee imaging
Marco Barbieri1, Lauren E Watkins1,2, Valentina Mazzoli1
1Department of Radiology, Stanford University, Stanford, CA, USA.
Magma (New York, N.Y.)
|May 4, 2023
Summary
A new flip angle correction method improves quantitative MRI mapping for osteoarthritis research. This technique enhances the accuracy of bilateral knee imaging, aiding in the detection of subtle biological changes and improving osteoarthritis assessment.
Area of Science:
- Biomedical Imaging
- Osteoarthritis Research
- Quantitative Magnetic Resonance Imaging (qMRI)
Background:
- Bilateral knee imaging is crucial for understanding osteoarthritis (OA) asymmetry.
- Quantitative double-echo in steady-state (qDESS) MRI provides simultaneous bilateral knee T1 mapping and high-resolution morphometry.
- Flip angle (FA) inaccuracies due to field inhomogeneities can compromise T1 measurement accuracy in qDESS.
Purpose of the Study:
- To develop and validate a pixel-wise flip angle (FA) correction method for quantitative double-echo in steady-state (qDESS) T1 mapping.
- To improve the accuracy and robustness of bilateral knee T1 measurements in the presence of magnetic field inhomogeneities.
- To enhance the sensitivity of qDESS T1 mapping for detecting osteoarthritis-related changes.
Main Methods:
- A novel pixel-wise FA correction method was developed for qDESS T1 mapping, utilizing an auxiliary T1 map to determine the actual FA.
- The technique was validated using phantom and in vivo simultaneous bilateral knee imaging.
- Longitudinal T1 measurements of femoral cartilage in healthy participants were performed to assess the association between FA variation and T1 values.
Main Results:
- The FA correction effectively mitigated T1 variations caused by magnetic field inhomogeneities.
- Left-right symmetry in T1 measurements improved after FA correction (from 0.69 to 0.74).
- The dependence of T1 values on FA was significantly reduced post-correction, with the linear coefficient decreasing from 24.3 ± 1.6 ms to 4.1 ± 1.8 ms, becoming non-significant (p > 0.01).
Conclusions:
- Flip angle correction is essential for mitigating qDESS T1 mapping sensitivity to field inhomogeneities.
- The proposed method enhances the robustness of bilateral qDESS T1 mapping, improving the detection of true biological changes.
- This approach facilitates more accurate and efficient evaluation of osteoarthritis pathophysiology in longitudinal and cross-sectional studies.
