RF aitifacts caused by metallic implants or instruments which get more prominent at 3 T: an in vitro study
RF aitifacts caused by metallic implants or instruments which get more prominent at 3 T: an in vitro study
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DOI：
10.1016/j.mri.2004.12.009
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发表时间：
2005-04-01
影响因子：
2.5
通讯作者：
Schick, F
中科院分区：
文献类型：
--
作者：
Graf, H;Lauer, UA;Schick, F
在体内或邻近具有高导电性的金属装置可能导致被调查组织中RF振幅B-1的显着改变，特别是在RF频率增加时，如果满足特定的电磁共振条件。在B-0=0.2, 1.5和3t时系统地研究了rf -金属相互作用效应，分析了铜线（d=1 mm， L=53和27 cm）以及以下钛或镍钛诺制成的器械和植入物的相关图像伪影：活检针、髋关节假体、血管支架和动脉瘤夹。样品在gd - dtpa掺杂的140 mM NaCl溶液中使用高读出带宽的自旋回波（SE）序列进行检测。采用自动变送器调节V-T、v -自动变送器电压V-T和手动降低变送器电压V-T检测B-1增强。在0.2 T时，超出支架管腔区域的屏蔽，没有观察到射频效应。在1.5 T时，铜线产生明显的射频伪影。在3t时，髋关节假体和活检针也出现射频伪影。在较低场强下具有明显腔内屏蔽的支架，在其外表面附近显示明显的B增强。©2005 Elsevier Inc.版权所有。
Metallic devices with high electrical conductivity inside or adjacent to the body might lead to marked alterations of the RF amplitude B-1 in the tissue under investigation, especially at increased RF frequency, and if specific conditions for electromagnetic resonance are fulfilled. RF-metal interaction effects were investigated systematically at B-0=0.2, 1.5 and 3 T analyzing correlated image artifacts for copper wires (d=1 mm, L=53 and 27 cm), and for following instruments and implants made of titanium or nitinol: biopsy needles, hip prostheses, vascular stents and aneurysm clips. The samples were examined in Gd-DTPA-doped 140 mM NaCl solution using spin-echo (SE) sequences with high readout bandwidth. Automatic transmitter adjustment V-T,V-auto and manually reduced transmitter voltage V-T were applied in order to detect B-1 enhancement. At 0.2 T, beyond the shielding of the luminal region of the stents, no RF effects were observed. At 1.5 T, the copper wires caused distinct RF artifacts. At 3 T, RF artifacts also appeared for the hip prostheses and the biopsy needles. Stents with pronounced luminal shielding at lower field strength revealed marked B, enhancement close to their outer surface. © 2005 Elsevier Inc. All rights reserved.