Impact of nanovectors in multimodal medical imaging

Medical imaging is currently revolutionizing the diagnosis and treatment of a variety of diseases. Several imaging modalities have been developed based on advances in science and engineering. The impact of these imaging tools has been further improved with the advent of various modern chemistries, leading to the development of contrast agents that serve further to localize the detection of diseased tissues. Several researchers are recently involved in engineering contrast agents that can generate contrast differences between tissues in multiple imaging modalities, enabling cross-referenced determination of anomalies. To establish these multimodal imaging agents, nanovectors have gained significance due to their key physicochemical properties.  The major focus of this review is on the engineering strategies of nanovectors for multimodal medical imaging. The review conceives the basic principles, major parameters, and limitations of imaging modalities, namely, magnetic resonance imaging (MRI), computed tomography (CT), and fluorescence imaging at the beginning. Drawbacks of traditional contrast agents and the demand for new contrast agents are established. The importance of multimodal imaging and the need for a single contrast agent for these imaging applications are elaborated. Finally, the advantages, limitations, and design considerations of nanovectors based on magnetic and metallic nanoparticles with surface modifications to reduce toxicity and enable targeted delivery as multimodal imaging agents are also emphasized.