Sonochemically produced fluorocarbon microspheres: A new class of magnetic resonance imaging agent

Publisher Website
Google Scholar
Abstract
With the intent of increasing the signal‐to‐noise ratio (SNR) of fluorine magnetic resonance imaging and enabling new applications, we have developed a novel class of agents based on protein encapsulation of fluorocarbons. Microspheres formed by high‐intensity ultrasound have a gaussian size distribution with an average diameter of 2.5 μm. As with conventional emulsions, these microspheres target the reticuloendothelial system. However, our sonochemically produced microspheres, because of a high encapsulation efficiency, show increases in the SNR of up to 300% compared to commercially available emulsions. We also demonstrate an increase in the circulation life‐time of the microspheres within the bloodstream by more than 30‐fold with a chemical modification of the outer surface of the microsphere. Finally, by encapsulating mixtures of fluorocarbons that undergo solid/liquid phase transitions, we can map temperature in the reticuloendothelial system, with signal changes of approximately 20‐fold over a 5°C range.