abstract |
A contrast-enhancing agent that has a saturation magnetization of at least 1.5 Tesla and that, when contacted with MRI radiation, provides a first gray scale response that is substantially uniform and that has a resolution of at least about 1 millimeter. When the contrast-enhancing agent is repeatedly contacted with said MRI radiation over a period of at least one year, it will repeatedly produce gray scale responses which are substantially identical to the first gray scale response. |