Linnemeyer Hannah, Shellock Frank G, Ahn Christina Y
Loyola Marymount University, 1 LMU Drive, Los Angeles, CA 90045.
Keck School of Medicine, University of Southern California and, Institute for Magnetic Resonance Safety, Education, and Research, Playa Del Rey, CA 90293.
Magn Reson Imaging. 2014 Apr;32(3):297-302. doi: 10.1016/j.mri.2013.11.003. Epub 2013 Dec 7.
A patient with a breast tissue expander may require a diagnostic assessment using magnetic resonance imaging (MRI). To ensure patient safety, this type of implant must undergo in vitro MRI testing using proper techniques. Therefore, this investigation evaluated MRI issues (i.e., magnetic field interactions, heating, and artifacts) at 3-Tesla for a breast tissue expander with a remote port.
A breast tissue expander with a remote port (Integra Breast Tissue Expander, Model 3612-06 with Standard Remote Port, PMT Corporation, Chanhassen, MN) underwent evaluation for magnetic field interactions (translational attraction and torque), MRI-related heating, and artifacts using standardized techniques. Heating was evaluated by placing the implant in a gelled-saline-filled phantom and MRI was performed using a transmit/receive RF body coil at an MR system reported, whole body averaged specific absorption rate of 2.9-W/kg. Artifacts were characterized using T1-weighted and GRE pulse sequences.
Magnetic field interactions were not substantial and, thus, will not pose a hazard to a patient in a 3-Tesla or less MRI environment. The highest temperature rise was 1.7°C, which is physiologically inconsequential. Artifacts were large in relation to the remote port and metal connector of the implant but will only present problems if the MR imaging area of interest is where these components are located.
A patient with this breast tissue expander with a remote port may safely undergo MRI at 3-Tesla or less under the conditions used for this investigation. These findings are the first reported at 3-Tesla for a tissue expander.
植入乳房组织扩张器的患者可能需要进行磁共振成像(MRI)诊断评估。为确保患者安全,此类植入物必须采用适当技术进行体外MRI测试。因此,本研究评估了一款带远程端口的乳房组织扩张器在3特斯拉磁场环境下的MRI相关问题(即磁场相互作用、发热和伪影)。
使用标准化技术,对一款带远程端口的乳房组织扩张器(Integra乳房组织扩张器,型号3612 - 06,标准远程端口,PMT公司,明尼苏达州查哈森)进行磁场相互作用(平移吸引力和扭矩)、MRI相关发热及伪影的评估。通过将植入物置于充满凝胶盐水的体模中来评估发热情况,并在报告的全身平均比吸收率为2.9瓦/千克的MR系统中,使用发射/接收射频体线圈进行MRI检查。使用T1加权和梯度回波(GRE)脉冲序列对伪影进行特征描述。
磁场相互作用并不显著,因此在3特斯拉及以下的MRI环境中不会对患者构成危害。最高温度上升为1.7°C,从生理角度来看无关紧要。与植入物的远程端口和金属连接器相关的伪影较大,但只有当感兴趣的MR成像区域位于这些部件所在位置时才会出现问题。
在本研究使用的条件下,植入这款带远程端口乳房组织扩张器的患者在3特斯拉及以下磁场环境中可安全地接受MRI检查。这些发现是首次在3特斯拉磁场环境下针对组织扩张器的报道。