Peters Josh P, Assaf Charbel, Brahms Arne, Them Kolja, Gerdsen Mirco, Herges Rainer, Hövener Jan-Bernd, Pravdivtsev Andrey N
Section Biomedical Imaging, Molecular Imaging North Competence Center (MOIN CC), Department of Radiology and Neuroradiology, University Hospital Schleswig-Holstein, Kiel University, Am Botanischen Garten 14, 24118, Kiel, Germany.
Otto Diels Institute for Organic Chemistry, Kiel University, Otto-Hahn Platz 4, 24098 Kiel, Germany.
Sci Adv. 2025 Sep 12;11(37):eadx2316. doi: 10.1126/sciadv.adx2316.
Gadolinium-based contrast agents revolutionized magnetic resonance imaging (MRI) by accelerating spin relaxation. In contrast, agents that decelerate relaxation were hitherto unknown. Such agents are highly desirable for metabolic imaging with hyperpolarized tracers such as N-pyridine, 1,4-C-succinate, and 1-N-nicotinamide, where valuable polarization decays rapidly, especially at low fields during transfer between polarizer and scanner. Here, we report on a previously unrecognized effect in which the tracers' longitudinal and transverse relaxation rates in aqueous solution are substantially reduced by adding nicotinamide, urea, glycerol, or dendrons. The impact on longitudinal relaxation is particularly pronounced at low magnetic fields and near the tracer's p where can be tripled. This mitigates polarization loss during transfer, so hitherto unsuitable, fast-relaxing molecules can be used now. This way, we achieved the N hyperpolarization of nearly 30% for 1-N-nicotinamide. This chemically induced deceleration of nuclear spin relaxation (CIDER) was confirmed using magnetic field-cycling experiments and offers broad potential for hyperpolarized magnetic resonance and beyond.
基于钆的造影剂通过加速自旋弛豫彻底改变了磁共振成像（MRI）。相比之下，此前尚不知道有能减缓弛豫的造影剂。对于使用超极化示踪剂（如N - 吡啶、1,4 - C - 琥珀酸盐和1 - N - 烟酰胺）进行代谢成像而言，这类造影剂是非常需要的，因为在极化剂与扫描仪之间转移时，尤其是在低场情况下，宝贵的极化会迅速衰减。在此，我们报告一种先前未被认识到的效应，即通过添加烟酰胺、尿素、甘油或树枝状分子，水溶液中示踪剂的纵向和横向弛豫速率会大幅降低。在低磁场以及接近示踪剂的p值（此处弛豫速率可增加两倍）时，对纵向弛豫的影响尤为显著。这减轻了转移过程中的极化损失，因此现在可以使用此前不合适的、快速弛豫的分子。通过这种方式，我们实现了1 - N - 烟酰胺近30%的N超极化。这种化学诱导的核自旋弛豫减速（CIDER）通过磁场循环实验得到了证实，并为超极化磁共振及其他领域提供了广阔潜力。
