Iimuro F T
Division of Metallurgy, Institute for Medical and Dental Engineering, Tokyo Medical and Dental University, Japan.
Dent Mater J. 1994 Jun;13(1):76-88. doi: 10.4012/dmj.13.76.
The use of a rare earth magnetic attachment system as a means of retaining dentures or maxillofacial prostheses results in artifacts, when magnetic resonance imaging (MRI) is used as a diagnostic tool. In such cases, the artifact is not caused by the magnet itself, but by the ferromagnetic stainless steel keeper that is placed in the body. This report evaluates such ferromagnetic stainless steel devices with respect to magnetic resonance imaging artifacts. A grid phantom and a 0.2 Tesla superconducting system were used to assess the imaging artifacts. The magnetic properties, shape, composition and size of ferromagnetic stainless steel devices were analyzed to study the relation MRI artifacts and ferromagnetic materials. The higher the magnetic permeability was, the greater the artifact produced. The size and volume of the material directly influence the artifact produced. The artifact size can be attenuated by the sequence used to obtain the images.
当使用磁共振成像（MRI）作为诊断工具时，使用稀土磁性附着系统来固定假牙或颌面修复体，会产生伪影。在这种情况下，伪影不是由磁体本身引起的，而是由置于体内的铁磁性不锈钢保持器导致的。本报告针对磁共振成像伪影对这类铁磁性不锈钢装置进行评估。使用网格体模和0.2特斯拉超导系统来评估成像伪影。分析铁磁性不锈钢装置的磁性、形状、成分和尺寸，以研究MRI伪影与铁磁材料之间的关系。磁导率越高，产生的伪影越大。材料的尺寸和体积直接影响所产生的伪影。通过获取图像所使用的序列，可使伪影尺寸减小。
