MARKER COMPOSITIONS

摘要

This invention relates to a set of aqueous marker compositions, each composition having a selected 1/Ti value which is substantially invariant over an at least 10 DEG C temperature range between 15 and 40 DEG C and preferably over an at least +/- 2 % magnetic field strength range about a selected field strength value between 0.01 and 5T and comprising an aqueous matrix material having a non-zero 1/Ti temperature dependence within said temperature range with distributed therein a first paramagnetic material having a Ti relaxivity which is substantially invariant within said range(s) and/or a second paramagnetic material having within said range(s) a Ti relaxivity which has a non-zero temperature dependence of opposite polarity to the temperature dependence of 1/Ti of said matrix material, said set containing a plurality of said compositions with different selected 1/Ti values preferably encompassing at least the range 1.0 to 2.5 s<-1>, said set preferably comprising at least one said composition containing said second paramagnetic material and at least one said composition containing said first paramagnetic material, where i in Ti is 1 or 2.