Fig. 1.

Experimental settings and BBB disruption in mice by MRI-guided focused ultrasound. (A) Diagram and protocol for BBB opening used in this experiment. Mice in the supine position were placed on the sonication table in the MR scanner. The ultrasound beam was focused through the intact skull on the target in the brain. (B and C) MR monitoring of BBB disruption and photographs of harvested brains showing BBB disruption induced by focused ultrasound. (B) Representative example with BBB disruption achieved by 0.6-MPa (peak negative-pressure amplitude) focused ultrasound exposure. (Upper) The BBB opening was easily monitored by leakage of the MR contrast agent into the brain parenchyma on axial (AX) and coronal (COR) MR images (arrows). (Lower Left) The location of the BBB opening was confirmed by trypan blue staining of the affected area. (Lower Right) No apparent macroscopic damage related to BBB disruption can be seen. (C) Magnitude of BBB disruption in the animal presented in B monitored by the MR-intensity change. Absolute values of the MR intensity of the sonicated target (○) and the contralateral side (control; ●) are plotted for repeated image acquisitions after sonication. Data are presented as the mean ± SD of four voxels.