Recent Advances in PET-MR Hybrid contrast agent

Abstract

<strong>Introduction</strong>: All of the Imaging modalities have advantages and disadvantages alone. So if we want to have the best and perfect image, combining these modalities produces something we desired. PET-MR images consist of morphologic and metabolic data. MRI and PET provide high spatial and contrast resolution and high sensitivity and molecular information respectively. Hybrid PET-MR devices need Hybrid contrast agent that can be used for both of modalities. <strong>Materials and Methods:</strong> Hybrid PET-MR contrast agents have several advantages in some cases imaging separately is used. For this purpose, unimodal approach method is underuse. In this method contrast agents for one of both techniques, given nonsimultaneously or simultaneously, are used to obtain multiparametric information. Other method is bimodal approach that A bimodal imaging agent is generated with the goal of providing an enhanced contrast agent for a specific purpose. the most logical use of this approach is to add a radionuclide component to an MR contrast agent, hence providing:

Better quantification (PET vs MR imaging), and Better whole body detectability, for guiding high-resolution MR imaging.

Most used MR contrast agent is SPION. To produce hybrid contrast agents in this method, a dextran-coated SPION is binded to a chelator like DOTA or DTPA or something else and PET tracer which is mentioned and sometimes an antibody or a peptide or agent of other modalities of imaging. <strong>Results:</strong> These agents are therefore capable of monitoring physicochemical properties in vivo and detecting enzyme deficiency or disorders. One of the most important use of hybrid contrast agents are in oncology. Lymph node imaging, tumor neoangiogenesis imaging and diffusion- weighted imaging (DWI) involve in applications of contrast agents. <strong>Conclusion:</strong> The use of PET-MR hybrid contrast agents is spreading daily and many project in different fields are performing and developed in recent years. Hybrid contrast agents are the most part of Medical Imaging in future.