2009 Fiscal Year Final Research Report
Development of No Induction Stent That Visualizes in Stent Lumen in MR Imaging
| Project/Area Number |
19591418
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Radiation science
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| Research Institution | Okayama University |
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Principal Investigator |
KOTO Hirokazu Okayama University, 大学院・保健学研究科, 教授 (60127511)
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| Co-Investigator(Kenkyū-buntansha) |
KURODA Masahiro 岡山大学, 大学院・保健学研究科, 教授 (50225306)
KANAZAWA Susumu 岡山大学, 大学院・医歯薬学総合研究科, 教授 (20243511)
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| Project Period (FY) |
2007 – 2009
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| Keywords | MRI / ステント / 可視化 / ステント内腔 / RF磁場 / 誘導磁場 |
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| Research Abstract |
In case that strictures are caused in the hollow viscera such as coronary artery, biliary tact, and esophagus, metallic cylinders consisting mesh pattern (called as stent) are inserted in the strictures in order to expand the narrowed portions. It is required to diagnose the presence of re-stricture in the stent after treatment, but we cannot diagnose the stent lumen using the MRI device.
We found out the causes of the above phenomenon in the MRI diagnosis using the simulation with the finite element method, as follows: The eddy currents are induced in the stent by the RF magnetic fields, B_1, applied for exciting the protons in the human body, and the eddy currents induce the associated magnetic fields. The induced magnetic fields arise so as to counterbalance the applied RF magnetic fields, B_1. As a result, the RF magnetic fields in the stent are decreased, and the flip angle of the protons becomes small.
This considerations led us to the valuable idea for visualizing the stent lumen, that is, the stent must be fabricated so as to have a solenoid-pattern structure, and the solenoidal stent must be placed in the MRI device so as to the central axis of the stent being perpendicular to the direction of the applied RF magnetic fields, B_1.
In the experiment, the lumen in the solenoidal stent was visualized by placing the central axis of the stent being perpendicular to the direction of the applied RF magnetic fields, B_1
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