Hyperpolarized lithium-6 as a sensor of nanomolar contrast agents.
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.
van Heeswijk
Ruud B
RB
Laboratory for Functional and Metabolic Imaging, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
Uffmann
Kai
K
Comment
Arnaud
A
Kurdzesau
Fiodar
F
Perazzolo
Chiara
C
Cudalbu
Cristina
C
Jannin
Sami
S
Konter
Jacobus A
JA
Hautle
Patrick
P
van den Brandt
Ben
B
Navon
Gil
G
van der Klink
Jacques J
JJ
Gruetter
Rolf
R
D000818:Animals; D001921:Brain / Q000378:metabolism*; D003287:Contrast Media / Q000032:analysis / Q000493:pharmacokinetics*; D007554:Isotopes / Q000493:pharmacokinetics; D008094:Lithium / Q000493:pharmacokinetics*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D008657:Metabolic Clearance Rate; D015336:Molecular Probe Techniques; D015335:Molecular Probes; D049329:Nanostructures / Q000737:chemistry*; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D051381:Rats; D017207:Rats, Sprague-Dawley
D003287:Contrast Media; D007554:Isotopes; D015335:Molecular Probes; D019275:Radiopharmaceuticals; D008094:Lithium