Weber B P, Goldring J E, Santogrossi T, Koestler H, Tziviskos G, Battmer R, Lenarz T h
Department of Otolaryngology, Medizinische Hochschule Hannover, Germany.
Am J Otol. 1998 Sep;19(5):584-90.
This study aimed to investigate the compatibility of the Clarion 1.2 magnet-containing cochlear implant with a 1.5-tesla (T) and 0.3-T magnetic resonance imager.
Cochlear implants restore functional hearing to patients with sensorineural deafness. With the rapidly increasing number of patients with cochlear implants, there is a need to investigate the implant's magnetic resonance imaging (MRI) compatibility.
The authors tested the potential torque and force on the metallic components of the implant, heating of the implant and surrounding tissue, unintentional output, implant damage, and image distortion. Tests were performed in both a 1.5-T and 0.3-T MRI.
The torque experienced by the implant in the 1.5-T MRI (0.19 nm) was large enough that it could potentially cause implant movement in some patients. An acceptable amount of torque (0.04 nm) was found in the 0.3-T MRI. Image distortion occurred in the area directly around the implant with a radius of up to 60 mm in the 1.5-T MRI and 100 mm in the 0.3-T MRI. In both MRI units, there was no detectable temperature increase or unintentional output. There was no implant damage except that with worst-case conditions, the internal magnet was demagnetized by 78.5% with the 1.5-T unit and 3.36% with the 0.3-T unit.
The authors recommend patients with cochlear implants avoid imaging in a 1.5-T MRI. The results suggest that the 0.3-T MRI poses little or no risks to patients with cochlear implants.
本研究旨在调查Clarion 1.2含磁铁人工耳蜗与1.5特斯拉（T）和0.3 T磁共振成像仪的兼容性。
人工耳蜗可恢复感音神经性聋患者的功能性听力。随着人工耳蜗植入患者数量的迅速增加，有必要研究该植入物的磁共振成像（MRI）兼容性。
作者测试了植入物金属部件上的潜在扭矩和力、植入物及周围组织的发热情况、意外输出、植入物损坏以及图像失真。测试在1.5 T和0.3 T MRI中均进行。
在1.5 T MRI中，植入物所受扭矩（0.19纳米）足够大，在某些患者中可能导致植入物移动。在0.3 T MRI中发现了可接受的扭矩量（0.04纳米）。在1.5 T MRI中，植入物周围半径达60毫米的区域以及在0.3 T MRI中半径达100毫米的区域出现了图像失真。在两个MRI设备中，均未检测到温度升高或意外输出。除了在最坏情况下，1.5 T设备使内部磁铁退磁78.5%，0.3 T设备使内部磁铁退磁3.36%外，未发生植入物损坏。
作者建议人工耳蜗植入患者避免在1.5 T MRI中进行成像。结果表明，0.3 T MRI对人工耳蜗植入患者几乎不构成风险或无风险。
