| 摘要 |
<p>A coated instrument for use in a magnetic resonance imaging (MRI) system, a method for designing such an instrument, and an MRI method including the steps of positioning a coated instrument (constructed in accordance with the invention) and a target in the imaging region of an MRI system, and operating the MRI system to produce an image showing both the target and the instrument. The instrument has a non-electrically conductive body covered by an electrically conductive, ultra-thin coating on at least part of the body. The thickness of the coating is determined (preferably experimentally) to be just large enough to cause the instrument to be positively shown in an MR image produced by the MRI system, but not so large as to obscure or distort unacceptably the image of a target (e.g., a typical target, such as human tissue, with which the instrument is to be imaged) in the same MR image (where both the instrument and target are in the MRI system's imaging region when the MRI system produces the MR image). The ultra-thin coating actually creates an imaging artifact which is sufficient to cause the instrument to be visible, but not so significant as to unacceptably distort the image of the intended target. In some preferred embodiments, the coating is a metal whose thickness is 2000 Angstroms or less. In other preferred embodiments, the coating is a metal whose thickness is of the same order of magnitude as its skin depth with respect to the radio frequency (RF) of the MRI system's RF field.</p> |
