Abstract
Focused ultrasound (FUS) with microbubbles has been discovered to locallyincrease the permeability of blood-brain barrier (BBB). However, bioeffects suchas erythrocyte extravasations and brain tissue damage may accompany. Therefore,development of a real-time imaging method to visualize occurrence of braininjury during opening of BBB by FUS is chief to improve the safety of thistechnology. The purpose of this study is to investigate the feasibility of usingthe high-frequency ultrasound imaging technique including contrast-enhanced andB-mode two images to monitor the transient responses of BBB disruption (BBBD)induced by FUS. We observed that BBBD with extensive hemorrhage and ischemia in1-MHz FUS with 1.1 MPa. The bright spots from the blood clots scatteringappeared in B-mode images and correspond to the map without perfusion in thecontrast-enhanced images. In addition, a relative safe power to BBBD withoutsuch bioeffects was 0.3 MPa. The results indicated that location of hyperechoicspots correlates with hemorrhage areas and the ischemia region consistent withthe BBBD areas under the cases of high FUS power. That reflected high-frequencyultrasound can provide the information of microhemorrhage and transient ischemiainformation during BBB open by FUS. © 2010 IEEE.