| 초록 |
Magnetic resonance imaging (MRI) is a high-resolution and clinically important imaging modality, which offers anatomical information, enabling diagnosis and prognosis of disease. A considerable effort has been investigated for the development of responsive MRI contrast agents capable of specifically indicating their local microenvironment such as pH, enzymatic activities, or redox status. In the presence of biological target, a switch in MRI contrast is triggered by the change of the relaxation efficiency which is derived from the variation of rotational dynamics or exchange rate of coordinated water, etc. Here, we introduce a new design principle of magnetism-based distance-dependent modulation of the relaxation efficiency. This magnetic resonance tuning (MRET) phenomenon occurs between a paramagnetic element and a superparamagnetic element, where the T1 MRI signal is tuned ON or OFF depending on the separation distance between the two elements. |
