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Simultaneous 3D T1$$ {\mathrm{T}}_1 $$, T2$$ {\mathrm{T}}_2 $$, and fat‐signal‐fraction mapping with respiratory‐motion correction for comprehensive liver tissue characterization at 0.55T
PurposeTo develop a framework for simultaneous three‐dimensional (3D) mapping of T1$$ {\mathrm{T}}_1 $$, T2$$ {\mathrm{T}}_2 $$, and fat signal fraction in the liver at 0.55 T.MethodsThe proposed sequence acquires four interleaved 3D volumes with a two‐echo Dixon readout. T1$$ {\mathrm{T}}_1 $$ and...
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Published in: | Magnetic resonance in medicine 2024-12, Vol.92 (6), p.2433-2446 |
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Main Authors: | , , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Online Access: | Get full text |
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Summary: | PurposeTo develop a framework for simultaneous three‐dimensional (3D) mapping of T1$$ {\mathrm{T}}_1 $$, T2$$ {\mathrm{T}}_2 $$, and fat signal fraction in the liver at 0.55 T.MethodsThe proposed sequence acquires four interleaved 3D volumes with a two‐echo Dixon readout. T1$$ {\mathrm{T}}_1 $$ and T2$$ {\mathrm{T}}_2 $$ are encoded into each volume via preparation modules, and dictionary matching allows simultaneous estimation of T1$$ {\mathrm{T}}_1 $$, T2$$ {\mathrm{T}}_2 $$, and M0$$ {M}_0 $$ for water and fat separately. 2D image navigators permit respiratory binning, and motion fields from nonrigid registration between bins are used in a nonrigid respiratory‐motion‐corrected reconstruction, enabling 100% scan efficiency from a free‐breathing acquisition. The integrated nature of the framework ensures the resulting maps are always co‐registered.ResultsT1$$ {\mathrm{T}}_1 $$, T2$$ {\mathrm{T}}_2 $$, and fat‐signal‐fraction measurements in phantoms correlated strongly (adjusted r2>0.98$$ {r}^2>0.98 $$) with reference measurements. Mean liver tissue parameter values in 10 healthy volunteers were 427±22$$ 427\pm 22 $$, 47.7±3.3 ms$$ 47.7\pm 3.3\;\mathrm{ms} $$, and 7±2%$$ 7\pm 2\% $$ for T1$$ {\mathrm{T}}_1 $$, T2$$ {\mathrm{T}}_2 $$, and fat signal fraction, giving biases of 71$$ 71 $$, −30.0 ms$$ -30.0\;\mathrm{ms} $$, and −5$$ -5 $$ percentage points, respectively, when compared to conventional methods.ConclusionA novel sequence for comprehensive characterization of liver tissue at 0.55 T was developed. The sequence provides co‐registered 3D T1$$ {\mathrm{T}}_1 $$, T2$$ {\mathrm{T}}_2 $$, and fat‐signal‐fraction maps with full coverage of the liver, from a single nine‐and‐a‐half‐minute free‐breathing scan. Further development is needed to achieve accurate proton‐density fat fraction (PDFF) estimation in vivo. |
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ISSN: | 0740-3194 1522-2594 |
DOI: | 10.1002/mrm.30236 |