Relaxivity of Gd-based contrast agents on X nuclei with long intrinsic relaxation times in aqueous solutions

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• 作者：Ruud B. van Heeswijk ; Sabrina Laus ; Florence D. Morgenthaler ; Rolf Gruetter
• 关键词：Gadolinium complexes ; Carbon-13 ; Lithium-6 ; Relaxivity ; Contrast agents
• 刊名：Magnetic Resonance Imaging
• 出版年：2007
• 期刊代码：188_0730725x
• 类别：med
• 出版时间：July 2007
• 卷：25
• 期：6
• 页码：821-825
• 文件大小：340 K

摘要

The relaxivity of commercially available gadolinium (Gd)-based contrast agents was studied for X-nuclei resonances with long intrinsic relaxation times ranging from 6 s to several hundred seconds. Omniscan in pure ¹³C formic acid had a relaxivity of 2.9 mM⁻¹ s⁻¹, whereas its relaxivity on glutamate C1 and C5 in aqueous solution was 0.5 mM⁻¹ s⁻¹. Both relaxivities allow the preparation of solutions with a predetermined short T₁ and suggest that in vitro substantial sensitivity gains in their measurement can be achieved.

⁶Li has a long intrinsic relaxation time, on the order of several minutes, which was strongly affected by the contrast agents. Relaxivity ranged from 0.1 mM⁻¹ s⁻¹ for Omniscan to 0.3 for Magnevist, whereas the relaxivity of Gd-DOTP was at 11 mM⁻¹ s⁻¹, which is two orders of magnitude higher. Overall, these experiments suggest that the presence of 0.1- to 10-μM contrast agents should be detectable, provided sufficient sensitivity is available, such as that afforded by hyperpolarization, recently introduced to in vivo imaging.