Unger E C, Fritz T A, Tilcock C, New T E
Department of Radiology, University of Arizona Health Sciences Center, Tucson 85724.
J Magn Reson Imaging. 1991 Nov-Dec;1(6):689-93. doi: 10.1002/jmri.1880010613.
The contrast agents gadolinium-DTPA (diethylenetriaminepentaacetic acid), Gd-DOTA (tetraazacyclododecanetetraacetic acid), and Gd-HP-DO3A (1,4,7-tris[carboxymethyl]-10-[2' hydroxypropyl]-1,4,7,10-tetraazacyclododecane) are used in humans as extracellular contrast agents. Although free Gd+ ion is toxic, the intact Gd3+ complexes are rapidly excreted and are relatively nontoxic. Decomplexation with release of free gadolinium is a relevant clinical concern in patients with altered renal clearance. Blood pool contrast agents currently under development may have longer clearance half-lives and be more prone to decomplexation. The present study was designed to evaluate the clearance of liposomally encapsulated Gd3+ complexes (DTPA, DOTA, and HP-DO3A). The macrocyclic compounds had more rapid and complete clearance than DTPA (P less than .05). Parallel studies with carbon-14 and Gd-153-labeled complexes showed significant differences (P less than .05) in the amount of these isotopes retained in the heart, kidney, lungs, and spleen, providing strong supportive evidence for in vivo decomplexation.
钆 - DTPA（二乙三胺五乙酸）、钆 - DOTA（四氮杂环十二烷四乙酸）和钆 - HP - DO3A（1,4,7 - 三[羧甲基] - 10 - [2' - 羟丙基] - 1,4,7,10 - 四氮杂环十二烷）等造影剂在人体中用作细胞外造影剂。尽管游离的钆离子具有毒性，但完整的钆络合物能迅速排出，且相对无毒。对于肾清除率改变的患者，钆的游离释放导致的脱络合是一个相关的临床问题。目前正在研发的血池造影剂可能具有更长的清除半衰期，并且更容易发生脱络合。本研究旨在评估脂质体包裹的钆络合物（DTPA、DOTA和HP - DO3A）的清除情况。大环化合物的清除比DTPA更快且更完全（P小于0.05）。对碳 - 14和钆 - 153标记的络合物进行的平行研究表明，这些同位素在心脏、肾脏、肺和脾脏中的保留量存在显著差异（P小于0.05），为体内脱络合提供了有力的支持证据。
