van Heeswijk Ruud B, Uffmann Kai, Comment Arnaud, Kurdzesau Fiodar, Perazzolo Chiara, Cudalbu Cristina, Jannin Sami, Konter Jacobus A, Hautle Patrick, van den Brandt Ben, Navon Gil, van der Klink Jacques J, Gruetter Rolf
Laboratory for Functional and Metabolic Imaging, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
Magn Reson Med. 2009 Jun;61(6):1489-93. doi: 10.1002/mrm.21952.
Lithium is widely used in psychotherapy. The (6)Li isotope has a long intrinsic longitudinal relaxation time T(1) on the order of minutes, making it an ideal candidate for hyperpolarization experiments. In the present study we demonstrated that lithium-6 can be readily hyperpolarized within 30 min, while retaining a long polarization decay time on the order of a minute. We used the intrinsically long relaxation time for the detection of 500 nM contrast agent in vitro. Hyperpolarized lithium-6 was administered to the rat and its signal retained a decay time on the order of 70 sec in vivo. Localization experiments imply that the lithium signal originated from within the brain and that it was detectable up to 5 min after administration. We conclude that the detection of submicromolar contrast agents using hyperpolarized NMR nuclei such as (6)Li may provide a novel avenue for molecular imaging.
锂广泛应用于心理治疗。锂-6同位素具有长达数分钟的固有纵向弛豫时间T(1)，这使其成为超极化实验的理想候选对象。在本研究中，我们证明了锂-6能够在30分钟内轻松实现超极化，同时保持长达一分钟左右的极化衰减时间。我们利用其固有的长弛豫时间在体外检测500 nM的造影剂。将超极化的锂-6注射到大鼠体内，其信号在体内的衰减时间约为70秒。定位实验表明，锂信号源自大脑内部，并且在注射后长达5分钟都可检测到。我们得出结论，使用诸如锂-6等超极化核磁共振核来检测亚微摩尔级的造影剂可能为分子成像提供一条新途径。
