Metal coordinated pyrrole-based macrocycles as contrast agents for magnetic resonance imaging technologies: Synthesis and applications.

The number of scientific reports on the field of imaging in biomedical sciences is rising massively, with the emergence of “noninvasive” in vivo imaging technologies, of which Magnetic Resonance Imaging (MRI) is considered to be among the top techniques in modern Medical Imaging. These techniques manage to detect events at molecular and cellular levels, providing a faster diagnostic evaluation to oncology patients and consequently hastening drug development processes. Of the many contrast agents developed by Organic Chemists during the last decades, tetrapyrrolic macrocycles like porphyrins and related compounds, like phthalocyanines, represent some of the oldest, most widely studied chemical structures in biomedical applications. These macrocyclic structures display intrinsic affinity for tumor localization, and their well-described photosensitizing and photophysical features allured many scientists toward their potential use as contrast agents in a variety of in vivo imaging technologies, namely in the MRI technique. Furthermore, a special emphasis is put on the development of multimodal contrast agents, which may be the future of Medical Imaging. This review intends to give an insight on developments on MRI technologies involving tetrapyrrolic-based contrast agents for cancer detection. It is a Chemist’s view, regarding the synthesis of the crucial contrast agents, selecting influential milestones over the last few decades on this field, along with pertinent reflections pointing to future guidelines. [ABSTRACT FROM AUTHOR]