A Novel Design of Implantable Esophageal Stent to Reduce the MRI RF-Induced Heating

In this work, the magnetic resonance imaging (MRI) radio frequency (RF)-induced heating mechanism for an esophageal stent is discussed from the prospective of forward scattering and the reciprocity theorem. We conclude that the RF-induced heating largely depends on the induced currents on the surfac...

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Bibliographic Details
Published in:IEEE transactions on electromagnetic compatibility 2017-06, Vol.59 (3), p.805-812
Main Authors: Dawei Li, Xiaohe Ji, Jianfeng Zheng, Changwang Pan, Ji Chen, Kainz, Wolfgang
Format: Article
Language:English
Subjects:
Electromagnetic heating
Electromagnetics
Esophagus
Forward scattering
Heating
Implants
Magnetic resonance imaging
Magnetic resonance imaging (MRI)
Mathematical model
medical implants
MRI safety
NMR
Nuclear magnetic resonance
Radio frequency
radio frequency (RF)-induced heating
Reciprocity
Reciprocity theorem
specific absorption rate (SAR)
stent
Stents
Surgical implants
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Summary:In this work, the magnetic resonance imaging (MRI) radio frequency (RF)-induced heating mechanism for an esophageal stent is discussed from the prospective of forward scattering and the reciprocity theorem. We conclude that the RF-induced heating largely depends on the induced currents on the surface of the stent. Based on this understanding, a novel implantable segmented stent structure is developed to reduce the RF-induced heating of an esophageal stent under MRI procedures. By using a segmented structure, the specific absorption rate (SAR) for a 10-mm-radius and 98-mm-length stent decreased from 53.0 to 14.2 W/kg at a whole-body average SAR of 2 W/kg, and the maximum temperature rise over 15-min MRI exam is reduced from 4.52 to 1.72°C. The simulated results and experimental measurements agree with each other within the combined uncertainty and demonstrate the effectiveness of the structured stent design. Related to RF-induced heating, this novel design can be used to develop inherently safe esophageal stents.
ISSN:0018-9375
1558-187X
DOI:10.1109/TEMC.2016.2625812