Local Specific Absorption Rate in High-Pass Birdcage and Transverse Electromagnetic Body Coils for Multiple Human Body Models in Clinical Landmark Positions at 3T
Local Specific Absorption Rate in High-Pass Birdcage and Transverse Electromagnetic Body Coils for Multiple Human Body Models in Clinical Landmark Positions at 3T
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DOI：
10.1002/jmri.22544
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发表时间：
2011-05-01
影响因子：
4.4
通讯作者：
Hancu, Ileana
中科院分区：
文献类型：
--
作者：
Yeo, Desmond T. B.;Wang, Zhangwei;Hancu, Ileana
目的：利用电磁(EM)模拟来研究体型的影响。3T磁共振成像(MRI)中标志性位置和射频(RF)体线圈类型对峰值局部特定吸收率(SAR)的影响。材料和方法：通过数值计算4个人体模型(HBMS)在3个标志性位置(头部、心脏、骨盆)的峰值局部SAR，以高通鸟笼和横向电磁3T体线圈为例进行比较。在正常扫描模式下，局部SAR值被归一化到IEC全身平均SAR值2.0W/kg。与以前的报告一致，峰值局部SAR值通常出现在颈肩区域、横档附近或电学性质差异很大的组织之间。HBM类型对局部SAR峰值有显著影响，HBM越结实，四肢向梯级延伸，显示出最高的SAR。在以头部和心脏为中心的位置，也有较高的峰值SAR的趋势。所研究的线圈类型的影响在统计学上并不显著。结论：峰值局部SAR的大变异性表明需要包括多个HBM或地标位置。在评估车身线圈的安全性时。建议包括手臂靠近横档的HBM，以创建物理上可实现的高SAR场景。
Purpose: To use electromagnetic (EM) simulations to study the effects of body type. landmark position, and radiofrequency (RF) body coil type on peak local specific absorption rate (SAR) in 3T magnetic resonance imaging (MRI).Materials and Methods: Numerically computed peak local SAR for four human body models (HBMs) in three landmark positions (head, heart, pelvic) were compared for a high-pass birdcage and a transverse electromagnetic 3T body coil. Local SAR values were normalized to the IEC whole-body average SAR limit of 2.0 W/kg for normal scan mode.Results: Local SAR distributions were highly variable. Consistent with previous reports, the peak local SAR values generally occurred in the neck-shoulder area, near rungs, or between tissues of greatly differing electrical properties. The HBM type significantly influenced the peak local SAR, with stockier HBMs, extending extremities towards rungs, displaying the highest SAR. There was also a trend for higher peak SAR in the head-centric and heart-centric positions. The impact of the coil types studied was not statistically significant.Conclusion: The large variability in peak local SAR indicates the need to include more than one HBM or landmark position. when evaluating safety of body coils. It is recommended that an HBM with arms near the rungs be included to create physically realizable high-SAR scenarios.