Association between contrast-enhanced MR images and blood-brain barrier disruption following transcranial focused ultrasound.
OBJECTIVE
To investigate the correlation between the contrast-enhanced magnetic resonance imaging (MRI) signal and the duration of blood-brain barrier (BBB) disruption induced by focused ultrasound (FUS).


METHODS
FUS was applied to 45 rat brains in the presence of microbubbles, and these rats were scanned on a 3T MRI system at several timepoints. The rat brains were then studied using contrast-enhanced spin echo T1-weighted images. At the same time, BBB disruption was evaluated based on Evans blue (EB) extravasation. The relationship between the normalized signal intensity change of the MRI and EB extravasation was analyzed by least-squares linear regression and the calculation of correlation coefficients.


RESULTS
When MRI enhancement was quantitatively evaluated by EB extravasation, a strong correlation between the normalized signal intensity change of the MRI and EB extravasation was identified during BBB disruption after sonication. However, the correlation coefficient decreased as BBB closure occurred after sonication ended.


CONCLUSIONS
The contrast-enhanced MRI signal can potentially be used to evaluate the amount of chemotherapeutic agents entering the targeted tissue, but the accuracy of the assessment will be affected by the time interval since sonication.
Yang
Feng-Yi
FY
Department of Biomedical Imaging and Radiological Sciences, School of Biomedical Science and Engineering, National Yang-Ming University, Taipei, Taiwan. fyyang@ym.edu.tw
Horng
Shih-Cheng
SC
Lin
Yu-Shi
YS
Kao
Yi-Hsuan
YH
D000818:Animals; D001812:Blood-Brain Barrier / Q000000981:diagnostic imaging* / Q000473:pathology*; D003287:Contrast Media; D004195:Disease Models, Animal; D005070:Evans Blue; D005119:Extravasation of Diagnostic and Therapeutic Materials; D007090:Image Interpretation, Computer-Assisted; D016014:Linear Models; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D017585:Ultrasonography, Doppler, Transcranial / Q000009:adverse effects* / Q000379:methods
D003287:Contrast Media; D005070:Evans Blue