Excitation System for Magnetic Resonance Elastography Using Micro MRI
Magnetic resonance elastography (MRE) is a nondestructive method for measuring the hardness and softness of living tissue by means of magnetic resonance imaging (MRI) coupled with mechanical excitation of the subject. The shear modulus of a tissue is related to the velocity of transverse waves propa...
| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
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The Japan Society of Mechanical Engineers
2012-12-01
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| Series: | Journal of Biomechanical Science and Engineering |
| Subjects: | |
| Online Access: | https://www.jstage.jst.go.jp/article/jbse/7/4/7_463/_pdf/-char/en |
| _version_ | 1811225551914926080 |
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| author | Shigeru TADANO Kazuhiro FUJISAKI Hayato SUZUKI Seishin TAKAO Mikio SUGA Itsuro KAJIWARA Toru YAMAMOTO Yu JIANG Gen NAKAMURA |
| author_facet | Shigeru TADANO Kazuhiro FUJISAKI Hayato SUZUKI Seishin TAKAO Mikio SUGA Itsuro KAJIWARA Toru YAMAMOTO Yu JIANG Gen NAKAMURA |
| author_sort | Shigeru TADANO |
| collection | DOAJ |
| description | Magnetic resonance elastography (MRE) is a nondestructive method for measuring the hardness and softness of living tissue by means of magnetic resonance imaging (MRI) coupled with mechanical excitation of the subject. The shear modulus of a tissue is related to the velocity of transverse waves propagating through it, and local movements are obtained from MRI phase images. Micro MRI systems are available for high-resolution MRE measurements of soft materials. Longitudinal waves are effective for long-distance wave propagation from small excitation areas in micro MRI systems, and the transverse waves produced by the longitudinal waves can be used for elastography. This study proposes an excitation system comprising a high-power vibration generator and bar-shaped vibration transmitter made from an elastic material. The transmission characteristics of the glass-fiber-reinforced plastic bar-shaped transducer were evaluated by measuring the accelerations at its base and tip. The performance of the excitation system, which focused on the effects of frequency and amplitude, was investigated for measuring storage and loss modulus distributions in agarose gel. This system could transfer longitudinal waves with an amplitude of 0.5 mm and frequency between 50 and 250 Hz, without significant damping. Moreover, the excitation capabilities for gel phantoms were evaluated by MRE using 0.3T micro MRI equipment. A large amplitude of 0.5 mm and high frequency of 250 Hz produced less data scatter than smaller amplitudes and lower frequencies. MRE performance improved upon using strong excitations. |
| first_indexed | 2024-04-12T09:09:13Z |
| format | Article |
| id | doaj.art-6fd712bba3404ab0a39698d94cffa0cd |
| institution | Directory Open Access Journal |
| issn | 1880-9863 |
| language | English |
| last_indexed | 2024-04-12T09:09:13Z |
| publishDate | 2012-12-01 |
| publisher | The Japan Society of Mechanical Engineers |
| record_format | Article |
| series | Journal of Biomechanical Science and Engineering |
| spelling | doaj.art-6fd712bba3404ab0a39698d94cffa0cd2022-12-22T03:39:00ZengThe Japan Society of Mechanical EngineersJournal of Biomechanical Science and Engineering1880-98632012-12-017446347410.1299/jbse.7.463jbseExcitation System for Magnetic Resonance Elastography Using Micro MRIShigeru TADANO0Kazuhiro FUJISAKI1Hayato SUZUKI2Seishin TAKAO3Mikio SUGA4Itsuro KAJIWARA5Toru YAMAMOTO6Yu JIANG7Gen NAKAMURA8Division of Human Mechanical Systems and Design, Graduate School of Engineering, Hokkaido UniversityDivision of Human Mechanical Systems and Design, Graduate School of Engineering, Hokkaido UniversityDivision of Human Mechanical Systems and Design, Graduate School of Engineering, Hokkaido UniversityCooperative Department of Medical Physics and Engineering, Graduate School of Medicine, Hokkaido UniversityDepartment of Medical System Engineering, Faculty of Engineering, Chiba UniversityDivision of Human Mechanical Systems and Design, Graduate School of Engineering, Hokkaido UniversityDivision of Biomedical Science and Engineering, Faculty of Health Science, Hokkaido UniversityDepartment of Mathematics, Faculty of Science, Hokkaido UniversityDepartment of Mathematics, Faculty of Science, Hokkaido UniversityMagnetic resonance elastography (MRE) is a nondestructive method for measuring the hardness and softness of living tissue by means of magnetic resonance imaging (MRI) coupled with mechanical excitation of the subject. The shear modulus of a tissue is related to the velocity of transverse waves propagating through it, and local movements are obtained from MRI phase images. Micro MRI systems are available for high-resolution MRE measurements of soft materials. Longitudinal waves are effective for long-distance wave propagation from small excitation areas in micro MRI systems, and the transverse waves produced by the longitudinal waves can be used for elastography. This study proposes an excitation system comprising a high-power vibration generator and bar-shaped vibration transmitter made from an elastic material. The transmission characteristics of the glass-fiber-reinforced plastic bar-shaped transducer were evaluated by measuring the accelerations at its base and tip. The performance of the excitation system, which focused on the effects of frequency and amplitude, was investigated for measuring storage and loss modulus distributions in agarose gel. This system could transfer longitudinal waves with an amplitude of 0.5 mm and frequency between 50 and 250 Hz, without significant damping. Moreover, the excitation capabilities for gel phantoms were evaluated by MRE using 0.3T micro MRI equipment. A large amplitude of 0.5 mm and high frequency of 250 Hz produced less data scatter than smaller amplitudes and lower frequencies. MRE performance improved upon using strong excitations.https://www.jstage.jst.go.jp/article/jbse/7/4/7_463/_pdf/-char/enmagnetic resonance imagingelastographyviscoelasticityexcitationwave propagation |
| spellingShingle | Shigeru TADANO Kazuhiro FUJISAKI Hayato SUZUKI Seishin TAKAO Mikio SUGA Itsuro KAJIWARA Toru YAMAMOTO Yu JIANG Gen NAKAMURA Excitation System for Magnetic Resonance Elastography Using Micro MRI Journal of Biomechanical Science and Engineering magnetic resonance imaging elastography viscoelasticity excitation wave propagation |
| title | Excitation System for Magnetic Resonance Elastography Using Micro MRI |
| title_full | Excitation System for Magnetic Resonance Elastography Using Micro MRI |
| title_fullStr | Excitation System for Magnetic Resonance Elastography Using Micro MRI |
| title_full_unstemmed | Excitation System for Magnetic Resonance Elastography Using Micro MRI |
| title_short | Excitation System for Magnetic Resonance Elastography Using Micro MRI |
| title_sort | excitation system for magnetic resonance elastography using micro mri |
| topic | magnetic resonance imaging elastography viscoelasticity excitation wave propagation |
| url | https://www.jstage.jst.go.jp/article/jbse/7/4/7_463/_pdf/-char/en |
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