| 摘要 |
Homologs of Diester-DTPA-Paramagnetic compounds (such as dimethyl acetyl diethylene triamine triacetic acid) provide excellent contrast agents for magnetic resonance imaging (MRI). The magnetic dipole generated by the unpaired electron within the paramagnetic (PM) atom, causes a local reduction in the bulk magnetic field of the MRI system. The resulting shorting of the T1 (spin lattice) relaxation time in the local hydrogen protons within the area of interest, causes an intense "free induction signal" and a corresponding modulation in the collected scanning data. The tissue or organ of interest appears on the MRI display highlighted in white. Background tissue is displayed as darker or lower intensity greys. The ester homologs replace two carboxylic acids to form functional ester groups on the DTPA chelator. The homologs cause the Diester-DTPA-PM contrast agents to go into solution readily, and promotes organ selectivity.
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