Switching of MRI Contrast Agents with Ultrasound

Purpose The utility of (super)paramagnetic agents to enhance contrast in MRI has been for some time demonstrated in human studies. The contrast provided by these agents arises from their ability to achieve reductions in T1 and T2*. Another approach to designing contrast agents is to consider the use of ultrasound (US). We have developed a method involving the application of US in MRI in the presence of antibody coated magnetic nanoparticles to generate contrast. It is intersting to control their effect on MRI by additional parameters, which can be switched on and off externally, and depend on the properties of the surrounding tissue. Also, it suggests the use of low concentrations of the magnetic nanoparticles.