Fig. 4

MRI changes in sonicated myocardium. Axial T1w MRI revealed little contrast enhancement following pFUS at 1 (d–f) and 3 MPa (g–i) compared to sham controls (a–c). However, pFUS at 6 MPa resulted in significant hyperintensities in the regions of pFUS (j–l). Contrast enhancement in pFUS targeted regions (l) was not observed in untreated myocardium (k). 3D reconstruction confirmed hyperintensities were distinctly located around the sonicated myocardium (j). Images were normalized to the mean signal intensity of each heart for a group-wise comparison. m Fold changes of in intensities were significant (p < 0.05) in hearts treated at 6 MPa. n Hyperintensities following pFUS at 6 MPa are not observed 24 h post-sonication