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.
- Magnetic resonance imaging
- Temperature mapping
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging