Notification:
We are currently experiencing intermittent issues impacting performance. We apologize for the inconvenience.
By Topic

Contrast agent kinetics in the rabbit brain during exposure to focused ultrasound

Sign In

Cookies must be enabled to login.After enabling cookies , please use refresh or reload or ctrl+f5 on the browser for the login options.

Formats Non-Member Member
$31 $13
Learn how you can qualify for the best price for this item!
Become an IEEE Member or Subscribe to
IEEE Xplore for exclusive pricing!
close button

puzzle piece

IEEE membership options for an individual and IEEE Xplore subscriptions for an organization offer the most affordable access to essential journal articles, conference papers, standards, eBooks, and eLearning courses.

Learn more about:

IEEE membership

IEEE Xplore subscriptions

3 Author(s)
Goertz, D.E. ; Sunnybrook Health Sci. Centre, Toronto, ON ; Wright, C. ; Hynynen, K.

The objective of this study was to investigate the kinetics of contrast agent concentration within the brain when it is subjected to pulsed focused ultrasound. An ultrasound imaging array was mounted within the aperture of a 1.68 MHz focused therapy transducer. Experiments were performed in the brains of rabbits that had undergone craniotomies, with the therapy beam focus localized within one hemisphere. Pulse lengths of 10 ms were employed at repetition rates of 0.1-2 Hz and acoustic powers of 0.1-1 watts. Contrast imaging was performed for up to 9 minutes following the bolus injection of Definity. Contrast signal power was then quantified in regions of interest within the acoustic focus of the therapy beam, as well as in the contra-lateral hemisphere. Following the injection of the contrast agent, signals peaked within 10 seconds and then underwent a period of slow decay. Individual therapy pulses resulted in microbubble depletion within the focus for powers >=0.25 W, with full recovery of signal occurring within 1-3 seconds, depending on transmit power. As the pulse repetition rates increased, agent reperfusion between pulses was incomplete and the concentration within the beam was progressively diminished, to a degree dependent upon both power and repetition rates. These results demonstrate that microbubble concentration can be substantially influenced by destruction induced by therapeutic ultrasound pulses. The kinetics of this effect may therefore be a significant factor influencing the efficiency of BBB breakdown.

Published in:

Ultrasonics Symposium, 2008. IUS 2008. IEEE

Date of Conference:

2-5 Nov. 2008