Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan.
Acta Biomater. 2013 Sep;9(9):8433-9. doi: 10.1016/j.actbio.2013.05.017. Epub 2013 May 24.
Susceptibility artifacts generated in magnetic resonance (MR) images were quantitatively evaluated for various metals using a three-dimensional (3-D) artifact rendering to demonstrate the correlation between magnetic susceptibility and artifact volume. Ten metals (stainless steel, Co-Cr alloy, Nb, Ti, Zr, Mo, Al, Sn, Cu and Ag) were prepared, and their magnetic susceptibilities measured using a magnetic balance. Each metal was embedded in a Ni-doped agarose gel phantom and the MR images of the metal-containing phantoms were taken using 1.5 and 3.0 T MR scanners under both fast spin echo and gradient echo conditions. 3-D renderings of the artifacts were constructed from the images and the artifact volumes were calculated for each metal. The artifact volumes of metals decreased with decreasing magnetic susceptibility, with the exception of Ag. Although Sn possesses the lowest absolute magnetic susceptibility (1.8×10(-6)), the artifact volume from Cu (-7.8×10(-6)) was smaller than that of Sn. This is because the magnetic susceptibility of Cu was close to that of the agarose gel phantom (-7.3×10(-6)). Since the difference in magnetic susceptibility between the agarose and Sn is close to that between the agarose and Ag (-17.5×10(-6)), their artifact volumes were almost the same, although they formed artifacts that were reversed in all three dimensions.
采用三维（3-D）伪影渲染技术对磁共振（MR）图像中的易感性伪影进行定量评估，以证明磁性易感性与伪影体积之间的相关性。使用磁天平测量了十种金属（不锈钢、Co-Cr 合金、Nb、Ti、Zr、Mo、Al、Sn、Cu 和 Ag）的磁性。将每种金属嵌入到 Ni 掺杂琼脂糖凝胶模型中，并在 1.5 和 3.0 T MR 扫描仪上，在快速自旋回波和梯度回波条件下，拍摄含有金属的模型的 MR 图像。从图像构建伪影的 3-D 渲染图，并计算每个金属的伪影体积。金属的伪影体积随着磁性易感性的降低而减小，但 Ag 除外。尽管 Sn 具有最低的绝对磁性易感性（1.8×10（-6）），但来自 Cu（-7.8×10（-6））的伪影体积小于 Sn 的伪影体积。这是因为 Cu 的磁性易感性接近琼脂糖凝胶模型的磁性易感性（-7.3×10（-6））。由于琼脂糖和 Sn 之间的磁性易感性差异接近于琼脂糖和 Ag 之间的差异（-17.5×10（-6）），尽管它们形成了在所有三个维度上都相反的伪影，但它们的伪影体积几乎相同。
