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. Author manuscript; available in PMC: 2009 Aug 1.
Published in final edited form as: Ultrasonics. 2008 Apr 14;48(4):279–296. doi: 10.1016/j.ultras.2008.04.004

FIGURE 6.

FIGURE 6

Spectra acquired during 10 ms pulses at four different locations in the rabbit brain. The white arrows indicate the locations of the fundamental frequency of the ultrasound (260 kHz), as well as the second and third harmonics. (a)–(d): Spectra from sonications without Optison®. (e)–(h): Spectra from sonications at the same locations and exposure levels with Optison®. The sonication that produced the spectrum in (e) did not result in BBBD; in (f)–(h), BBB disruption was observed. In (g) and (h), the frequency spectrum was accompanied by wideband acoustic emission, which is indicated by a hump at approximately 650 kHz (black arrow), the central frequency of the receiver. The additional peaks (especially at lower frequencies) were artifacts in the signals presumably induced in the cables extending out of the MRI room. They were also observed in signals obtained with the ultrasound driving system disabled. (a), (e): 0.14 MPa; (b), (f): 0.29 MPa; (c), (g): 0.40 MPa; (d), (h): 0.57 MPa). Figure reproduced from [109] with permission.