Radio frequency magnetic field mapping of a 3 Tesla birdcage coil: experimental and theoretical dependence on sample properties.
The RF B(1) distribution was studied, theoretically and experimentally, in phantoms and in the head of volunteers using a 3 T MRI system equipped with a birdcage coil. Agreement between numerical simulation and experiment demonstrates that B(1) distortion at high field can be explained with 3D full-...
| Main Authors: | , , , |
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| Format: | Journal article |
| Language: | English |
| Published: |
2001
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| _version_ | 1797098620530458624 |
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| author | Alecci, M Collins, C Smith, M Jezzard, P |
| author_facet | Alecci, M Collins, C Smith, M Jezzard, P |
| author_sort | Alecci, M |
| collection | OXFORD |
| description | The RF B(1) distribution was studied, theoretically and experimentally, in phantoms and in the head of volunteers using a 3 T MRI system equipped with a birdcage coil. Agreement between numerical simulation and experiment demonstrates that B(1) distortion at high field can be explained with 3D full-Maxwell calculations. It was found that the B(1) distribution in the transverse plane is strongly dependent on the dielectric properties of the sample. We show that this is a consequence of RF penetration effects combined with RF standing wave effects. In contrast, along the birdcage coil z-axis the B(1) distribution is determined mainly by the coil geometry. In the transverse plane, the region of B(1) uniformity (within 10% of the maximum) was 15 cm with oil, 6 cm with distilled water, 11 cm with saline, and 10 cm in the head. Along z the B(1) uniformity was 9 cm with phantoms and 7 cm in the head. |
| first_indexed | 2024-03-07T05:12:14Z |
| format | Journal article |
| id | oxford-uuid:dbf34409-9a72-441e-a699-f27626fdcf24 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T05:12:14Z |
| publishDate | 2001 |
| record_format | dspace |
| spelling | oxford-uuid:dbf34409-9a72-441e-a699-f27626fdcf242022-03-27T09:14:18ZRadio frequency magnetic field mapping of a 3 Tesla birdcage coil: experimental and theoretical dependence on sample properties.Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:dbf34409-9a72-441e-a699-f27626fdcf24EnglishSymplectic Elements at Oxford2001Alecci, MCollins, CSmith, MJezzard, PThe RF B(1) distribution was studied, theoretically and experimentally, in phantoms and in the head of volunteers using a 3 T MRI system equipped with a birdcage coil. Agreement between numerical simulation and experiment demonstrates that B(1) distortion at high field can be explained with 3D full-Maxwell calculations. It was found that the B(1) distribution in the transverse plane is strongly dependent on the dielectric properties of the sample. We show that this is a consequence of RF penetration effects combined with RF standing wave effects. In contrast, along the birdcage coil z-axis the B(1) distribution is determined mainly by the coil geometry. In the transverse plane, the region of B(1) uniformity (within 10% of the maximum) was 15 cm with oil, 6 cm with distilled water, 11 cm with saline, and 10 cm in the head. Along z the B(1) uniformity was 9 cm with phantoms and 7 cm in the head. |
| spellingShingle | Alecci, M Collins, C Smith, M Jezzard, P Radio frequency magnetic field mapping of a 3 Tesla birdcage coil: experimental and theoretical dependence on sample properties. |
| title | Radio frequency magnetic field mapping of a 3 Tesla birdcage coil: experimental and theoretical dependence on sample properties. |
| title_full | Radio frequency magnetic field mapping of a 3 Tesla birdcage coil: experimental and theoretical dependence on sample properties. |
| title_fullStr | Radio frequency magnetic field mapping of a 3 Tesla birdcage coil: experimental and theoretical dependence on sample properties. |
| title_full_unstemmed | Radio frequency magnetic field mapping of a 3 Tesla birdcage coil: experimental and theoretical dependence on sample properties. |
| title_short | Radio frequency magnetic field mapping of a 3 Tesla birdcage coil: experimental and theoretical dependence on sample properties. |
| title_sort | radio frequency magnetic field mapping of a 3 tesla birdcage coil experimental and theoretical dependence on sample properties |
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