Large-volume FUS-BBBO delivery outcome using different strategies. (a) Photographs of the ex vivo brain slices containing the brainstem from all mice treated by interleaved-bolus (upper left), interleaved-infusion (bottom left), serial-bolus (upper right), and serial-infusion (bottom right). (b) Corresponding fluorescence images of the brain slices shown in (a). Scale bar = 5 mm. (c) Group analysis of the fluorescence intensities for different strategies. (d) Quantification of the spatial homogeneity of Evans blue distribution. A lower coefficient of variation indicates higher homogeneity. (Multiple comparisons with Brown-Forsythe and Welch ANOVA corrected by Dunnett’s post-hoc test: * p < 0.05, ** p < 0.01). FUS parameters: center frequency =1.5 MHz, peak negative pressure = 0.45 MPa, pulse repetition frequency = 5 Hz, cycle number = 10,000, pulse length = 6.67 ms, total sonication duration = 3 minutes.