热解石墨泡沫：一种被动磁导率匹配材料。
Pyrolytic graphite foam: a passive magnetic susceptibility matching material.
机构信息
Berkeley/UCSF Bioengineering Joint Graduate Group, University of California, Berkeley, California 94720, USA.
出版信息
J Magn Reson Imaging. 2010 Sep;32(3):684-91. doi: 10.1002/jmri.22270.
PURPOSE
To evaluate a novel soft, lightweight cushion that can match the magnetic susceptibility of human tissue. The magnetic susceptibility difference between air and tissue produces field inhomogeneities in the B(0) field, which leads to susceptibility artifacts in magnetic resonance imaging (MRI) studies.
MATERIALS AND METHODS
Pyrolytic graphite (PG) microparticles were uniformly embedded into a foam cushion to reduce or eliminate field inhomogeneities at accessible air and tissue interfaces. 3T MR images and field maps of an air/water/PG foam phantom were acquired. Q measurements on a 4T tuned head coil and pulse sequence heating tests at 3T were also performed.
RESULTS
The PG foam improved susceptibility matching, reduced the field perturbations in phantoms, does not heat, and is nonconductive.
CONCLUSION
The susceptibility matched PG foam is lightweight, safe for patient use, adds no noise or MRI artifacts, is compatible with radiofrequency coil arrays, and improves B(0) homogeneity, which enables more robust MR studies.
目的
评估一种新型柔软、轻便的衬垫，使其能够匹配人体组织的磁化率。空气和组织之间的磁化率差异会在 B(0)场中产生磁场不均匀性，从而导致磁共振成像 (MRI) 研究中的磁化率伪影。
材料和方法
将热解石墨 (PG) 微颗粒均匀嵌入泡沫衬垫中，以减少或消除可接近的空气和组织界面处的磁场不均匀性。对空气/水/PG 泡沫体模进行了 3T MR 图像和磁场图采集。还在 4T 调谐头线圈上进行了 Q 测量和 3T 脉冲序列加热测试。
结果
PG 泡沫改善了磁化率匹配，减少了体模中的磁场干扰，不会发热且不导电。
结论
具有匹配磁化率的 PG 泡沫轻便、安全，不会增加噪声或 MRI 伪影，与射频线圈阵列兼容，并改善了 B(0) 均匀性，从而能够进行更稳健的磁共振研究。
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