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A quantitative pressure and microbubble‐size dependence study of focused ultrasound‐induced blood‐brain barrier opening reversibility in vivo using MRI
Author(s) -
Samiotaki Gesthimani,
Vlachos Fotios,
Tung YaoSheng,
Konofagou Elisa E.
Publication year - 2012
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.23063
Subject(s) - microbubbles , ultrasound , parenchyma , blood–brain barrier , sonication , biomedical engineering , focused ultrasound , chemistry , in vivo , mechanical index , nuclear magnetic resonance , materials science , magnetic resonance imaging , pathology , medicine , central nervous system , radiology , chromatography , physics , microbiology and biotechnology , biology , endocrinology
Focused ultrasound in conjunction with the systemic administration of microbubbles has been shown to open the blood‐brain barrier (BBB) selectively, noninvasively and reversibly. In this study, we investigate the dependence of the BBB opening's reversibility on the peak‐rarefactional pressure (0.30–0.60 MPa) as well as the microbubble size (diameters of 1–2, 4–5, or 6–8 μm) in mice using contrast‐enhanced T 1 ‐weighted (CE‐ T 1 ) MR images (9.4 T). Volumetric measurements of the diffusion of Gd‐DTPA‐BMA into the brain parenchyma were used for the quantification of the BBB‐opened region on the day of sonication and up to 5 days thereafter. The volume of opening was found to increase with both pressure and microbubble diameter. The duration required for closing was found to be proportional to the volume of opening on the day of opening, and ranged from 24 h, for the smaller microbubbles, to 5 days at high peak‐rarefactional pressures. Overall, larger bubbles did not show significant differences. Also, the extent of BBB opening decreased radially towards the focal region until the BBB's integrity was restored. In the cases where histological damage was detected, it was found to be highly correlated with hyperintensity on the precontrast T 1 images. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.