Experimental brain abscess: enhanced sonography and pathologic correlation.

A new sonographic contrast agent, gelatin-encapsulated nitrogen microbubbles, was introduced intraarterially to enhance the high-resolution sonographic scan of an experimental brain abscess. The echogenicity produced by the microbubbles correlated closely to the site and distribution of abscess neovascularity. The contrast agent aided in the detection of small necrotic centers in the late stages of abscess evolution when these centers were not visualized on noncontrast sonograms. The echogenic effect of the microbubbles was maximum immediately after injection; it decreased by 5 min and had virtually disappeared at 15 min.