Short echo time dual-frequency MR Elastography with Optimal Control RF pulses
Abstract Magnetic Resonance Elastography (MRE) quantifies the mechanical properties of tissues, typically applying motion encoding gradients (MEG). Multifrequency results allow better characterizations of tissues using data usually acquired through sequential monofrequency experiments. High frequenc...
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| Format: | Article |
| Language: | English |
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Nature Portfolio
2022-01-01
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| Series: | Scientific Reports |
| Online Access: | https://doi.org/10.1038/s41598-022-05262-3 |
| _version_ | 1819349699121905664 |
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| author | Pilar Sango-Solanas Kevin Tse Ve Koon Eric Van Reeth Helene Ratiney Fabien Millioz Cyrielle Caussy Olivier Beuf |
| author_facet | Pilar Sango-Solanas Kevin Tse Ve Koon Eric Van Reeth Helene Ratiney Fabien Millioz Cyrielle Caussy Olivier Beuf |
| author_sort | Pilar Sango-Solanas |
| collection | DOAJ |
| description | Abstract Magnetic Resonance Elastography (MRE) quantifies the mechanical properties of tissues, typically applying motion encoding gradients (MEG). Multifrequency results allow better characterizations of tissues using data usually acquired through sequential monofrequency experiments. High frequencies are difficult to reach due to slew rate limitations and low frequencies induce long TEs, yielding magnitude images with low SNR. We propose a novel strategy to perform simultaneous multifrequency MRE in the absence of MEGs: using RF pulses designed via the Optimal Control (OC) theory. Such pulses control the spatial distribution of the MRI magnetization phase so that the resulting transverse magnetization reproduces the phase pattern of an MRE acquisition. The pulse is applied with a constant gradient during the multifrequency mechanical excitation to simultaneously achieve slice selection and motion encoding. The phase offset sampling strategy can be adapted according to the excitation frequencies to reduce the acquisition time. Phantom experiments were run to compare the classical monofrequency MRE to the OC based dual-frequency MRE method and showed excellent agreement between the reconstructed shear storage modulus G′. Our method could be applied to simultaneously acquire low and high frequency components, which are difficult to encode with the classical MEG MRE strategy. |
| first_indexed | 2024-12-24T19:04:40Z |
| format | Article |
| id | doaj.art-d4627aba95724110a7a5dd4835778fca |
| institution | Directory Open Access Journal |
| issn | 2045-2322 |
| language | English |
| last_indexed | 2024-12-24T19:04:40Z |
| publishDate | 2022-01-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | Scientific Reports |
| spelling | doaj.art-d4627aba95724110a7a5dd4835778fca2022-12-21T16:43:08ZengNature PortfolioScientific Reports2045-23222022-01-0112111210.1038/s41598-022-05262-3Short echo time dual-frequency MR Elastography with Optimal Control RF pulsesPilar Sango-Solanas0Kevin Tse Ve Koon1Eric Van Reeth2Helene Ratiney3Fabien Millioz4Cyrielle Caussy5Olivier Beuf6Univ Lyon, INSA Lyon, Inserm, UCBL, CNRS, CREATIS, UMR5220, U1294Univ Lyon, INSA Lyon, Inserm, UCBL, CNRS, CREATIS, UMR5220, U1294Univ Lyon, INSA Lyon, Inserm, UCBL, CNRS, CREATIS, UMR5220, U1294Univ Lyon, INSA Lyon, Inserm, UCBL, CNRS, CREATIS, UMR5220, U1294Univ Lyon, INSA Lyon, Inserm, UCBL, CNRS, CREATIS, UMR5220, U1294Univ Lyon, INSERM, INRA, INSA Lyon, UCBL, CarMen LaboratoryUniv Lyon, INSA Lyon, Inserm, UCBL, CNRS, CREATIS, UMR5220, U1294Abstract Magnetic Resonance Elastography (MRE) quantifies the mechanical properties of tissues, typically applying motion encoding gradients (MEG). Multifrequency results allow better characterizations of tissues using data usually acquired through sequential monofrequency experiments. High frequencies are difficult to reach due to slew rate limitations and low frequencies induce long TEs, yielding magnitude images with low SNR. We propose a novel strategy to perform simultaneous multifrequency MRE in the absence of MEGs: using RF pulses designed via the Optimal Control (OC) theory. Such pulses control the spatial distribution of the MRI magnetization phase so that the resulting transverse magnetization reproduces the phase pattern of an MRE acquisition. The pulse is applied with a constant gradient during the multifrequency mechanical excitation to simultaneously achieve slice selection and motion encoding. The phase offset sampling strategy can be adapted according to the excitation frequencies to reduce the acquisition time. Phantom experiments were run to compare the classical monofrequency MRE to the OC based dual-frequency MRE method and showed excellent agreement between the reconstructed shear storage modulus G′. Our method could be applied to simultaneously acquire low and high frequency components, which are difficult to encode with the classical MEG MRE strategy.https://doi.org/10.1038/s41598-022-05262-3 |
| spellingShingle | Pilar Sango-Solanas Kevin Tse Ve Koon Eric Van Reeth Helene Ratiney Fabien Millioz Cyrielle Caussy Olivier Beuf Short echo time dual-frequency MR Elastography with Optimal Control RF pulses Scientific Reports |
| title | Short echo time dual-frequency MR Elastography with Optimal Control RF pulses |
| title_full | Short echo time dual-frequency MR Elastography with Optimal Control RF pulses |
| title_fullStr | Short echo time dual-frequency MR Elastography with Optimal Control RF pulses |
| title_full_unstemmed | Short echo time dual-frequency MR Elastography with Optimal Control RF pulses |
| title_short | Short echo time dual-frequency MR Elastography with Optimal Control RF pulses |
| title_sort | short echo time dual frequency mr elastography with optimal control rf pulses |
| url | https://doi.org/10.1038/s41598-022-05262-3 |
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