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Radiology. 2001 Sep;220(3):640-6.

Noninvasive MR imaging-guided focal opening of the blood-brain barrier in rabbits.

Author information

1
Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, 75 Francis St, Boston, MA 02115, USA. kullervo@bwh.harvard.edu

Abstract

PURPOSE:

To determine if focused ultrasound beams can be used to locally open the blood-brain barrier without damage to surrounding brain tissue and if magnetic resonance (MR) imaging can be used to monitor this procedure.

MATERIALS AND METHODS:

The brains of 18 rabbits were sonicated (pulsed sonication) in four to six locations, with temporal peak acoustic power ranging from 0.2 to 11.5 W. Prior to each sonication, a bolus of ultrasonographic (US) contrast agent was injected into the ear vein of the rabbit. A series of fast or spoiled gradient-echo MR images were obtained during the sonications to monitor the temperature elevation and potential tissue changes. Contrast material-enhanced MR images obtained minutes after sonications and repeated 1-48 hours later were used to depict blood-brain barrier opening. Whole brain histologic evaluation was performed.

RESULTS:

Opening of the blood-brain barrier was confirmed with detection of MR imaging contrast agent at the targeted locations. The lowest power levels used produced blood-brain barrier opening without damage to the surrounding neurons. Contrast enhancement correlated with the focal signal intensity changes in the magnitude fast spoiled gradient-echo MR images.

CONCLUSION:

The blood-brain barrier can be consistently opened with focused ultrasound exposures in the presence of a US contrast agent. MR imaging signal intensity changes may be useful in the detection of blood-brain barrier opening during sonication.

PMID:
11526261
DOI:
10.1148/radiol.2202001804
[Indexed for MEDLINE]

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