Fig. 1
Establishment of BBBD conditions for the FUS parameters. (A) Representative contrast-enhanced T1 weighted MR images and relative MR signal intensity of contrast agents in the mouse brain after sonication with FUS parameters: 0.25 MPa (three left panels) and 0.42 MPa (three right panels). Time series (6, 12, and 18 min) of coronal MR images showed localized BBBD at four targeted points of the thalamus region and contrast changes. (B) The line graph illustrates the relative MR signal intensity corresponding to BBB permeability changes at the three time-points after contrast agent injection (n = 3, P = 0.0002; two-tailed Student’s t-test). Scale bars are 2 mm. (C–D) The Ktrans mapping and mean values in the sonicated area of the hippocampus region for each FUS parameter are presented for comparison (n = 3, P < 0.0001; two-tailed Student’s t-test). (E) Representative acoustic emission spectra of before (black line) and after (red line) BBB-opening according to 0.25 MPa and 0.42 MPa. The black arrows indicate the locations of the fundamental frequency of the ultrasound and the second, third, and fourth harmonics. Arrowheads indicate subharmonics and ultraharmonics. (F) The bar graph presents the mean value of the cavitation dose calculated by integrating all spectra (n = 3, *P < 0.05; two-tailed Student’s t-test). (G–H) Histological analysis of the mouse brain after BBB opening with H&E (G) and FJC (H) staining. The black arrows in H&E stained tissue indicate petechiae (scale bar = 50 μm) (G). Degenerating neurons showed green fluorescence (FJC-positive cells, green color; DAPI, blue; scale bar = 10 μm) (H). (I) The intensity of FJC-positive cells measured and converted to relative intensity compared with the contralateral region (mean ± SD, multiple ROIs (n = 20) per hemisphere, P < 0.001; two-tailed Student’s t-test)