Molecular imaging using hyperpolarized13C

K Golman, L E Olsson, O Axelsson, S Månsson, M Karlsson, J S Petersson
2003 British Journal of Radiology  
MRI provides unsurpassed soft tissue contrast, but the inherent low sensitivity of this modality has limited the clinical use to imaging of water protons. With hyperpolarization techniques, the signal from a given number of nuclear spins can be raised more than 100 000 times. The strong signal enhancement enables imaging of nuclei other than protons, e.g. 13 C and 15 N, and their molecular distribution in vivo can be visualized in a clinically relevant time window. This article reviews
more » ... le reviews different hyperpolarization techniques and some of the many application areas. As an example, experiments are presented where hyperpolarized 13 C nuclei have been injected into rabbits, followed by rapid 13 C MRI with high spatial resolution (scan time ,1 s and 1.0 mm in-plane resolution). The high degree of polarization thus enabled mapping of the molecular distribution within various organs, a few seconds after injection. The hyperpolarized 13 C MRI technique allows a selective identification of the molecules that give rise to the MR signal, offering direct molecular imaging. Imaging of hyperpolarized agents The concentration of a hyperpolarized imaging agent may be 0.5 M in the injection syringe and decrease to 1-20 mM in vivo, due to dilution in the vascular system. This is far below the typical 1 H concentration of 80 M, but since the hyperpolarization can enhance the signal up to
doi:10.1259/bjr/26631666 pmid:15572334 fatcat:tnae34ng4bbnzi5q6e7txcm374