Pulse sequence and timing of contrast-enhanced MRI for assessing blood-brain barrier disruption after transcranial focused ultrasound in the presence of hemorrhage.
OBJECTIVE
To optimize the timing of contrast-enhanced magnetic resonance imaging (MRI) that best indicates blood-brain barrier (BBB) disruption induced by focused ultrasound (FUS) along with an ultrasound contrast agent (UCA) and to verify that the contrast-enhanced spin-echo MRI sequence can indicate the degree and location of BBB disruption in the presence of hemorrhage better than a gradient-echo sequence.


METHODS
Sonication was applied to 12 rat brains with four different doses of UCA to cause variable degrees of hemorrhage. Two imaging sequences were performed to acquire T1-weighted (T1W) images at two time-points after the administration of a T1-shortening contrast agent. The contrast enhancement at the sonicated regions was quantified and correlated against Evans blue (EB) staining.


RESULTS
The spin-echo T1W images at 10 minutes post-contrast enhancement showed the best correlation with EB staining in both quantity of EB extravasation (r = 0.812; P < 0.01) and spatial distribution (r = 0.528, P < 0.01). This capability was more robust than the gradient-echo sequence.


CONCLUSIONS
Our results suggest that contrast-enhanced T1W spin-echo sequence acquired in the early phase post-contrast enhancement should be considered to monitor the degree and location of BBB disruption under the possibility of hemorrhage induced by FUS.
Weng
Jun-Cheng
JC
Center for Optoelectronic Biomedicine, College of Medicine, National Taiwan University, Taipei, Taiwan.
Wu
Sheng-Kai
SK
Yang
Feng-Yi
FY
Lin
Win-Li
WL
Tseng
Wen-Yih Isaac
WY
D000818:Animals; D001812:Blood-Brain Barrier / Q000473:pathology*; D001921:Brain / Q000473:pathology; D003287:Contrast Media / Q000494:pharmacology; D005070:Evans Blue / Q000494:pharmacology; D006470:Hemorrhage / Q000473:pathology*; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D013010:Sonication; D013997:Time Factors; D014463:Ultrasonography / Q000379:methods
D003287:Contrast Media; D005070:Evans Blue