Lipid-coated uniform microbubbles for earlier sonographic detection of brain tumors.

Rapid technological improvements have fostered the continued clinical development of intraoperative neurosonology, despite the fact that no suitable contrast media have been available for ultrasound studies. Because they can be made of uniform size (99% are less than 4.5 mum in diameter) and are thought to cross disruptions in the tumor vessels, artificial lipid-coated microbubbles can fill this gap. Furthermore, these microbubbles are stable in vitro for at least 6 months, with an in vivo halflife of 20 hours or more. This study demonstrated that lipid-coated microbubbles injected intravascularly can intensify echoes from rat brain gliomas. Specifically, when this standardized microbubble contrast agent was injected intravenously daily in rats, the time to visual ultrasonic detection of developing brain tumors (C-6 gliomas) was 4.09 days (n = 11) after tumor inoculation, versus 6.67 days (n = 9) to detection without microbubble injection (Z = -3.71, p = 0.0004).