Development of Clinical Contrast Agents

The story of MRI CAs began with X-ray CAs. DTPA (diethyltriaminepentaacetic acid) was widely used as a chelate for the detoxification and solubilization of bismuth, which is a metal ion in X-ray CAs [3], DTPA attracted the attention of scientist, who developed Gd-DTPA as the first paramagnetic complex in MRI clinical studies [4], It was initially applied to image the central nervous system (CNS). However, owing to its superior anatomical contrast enhancement, it was later applied to the imaging of cardiovascular and neurovascular systems, and in oncology [5], 

The development of Gd and lanthanide (Ln) complexes for uses as MRI CAs has given rise to a rich lanthanide chemistry. However, the multidisciplinary field of monitoring physiological changes remains a challenge, as in vivo parameters such as pH, partial oxygen pressure (pOi), 

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