Fig. 4
Low-intensity focused ultrasound (LIFU)-driven phase transition and PFP@PDM-PEG ultrasound imaging. A Optical microscopy images of PFP@PDM-PEG irradiated with LIFU (2 W cm−2) for 0–4 min. Scale bar: 200 μm. B Ultrasound images of PFP@PDM-PEG after LIFU irradiation with various parameters. C In vivo ultrasound images of US mode, CEUS mode and the parametric peak intensity (PI) color map under LIFU irradiation. Quantitative analysis of the mean intensity in the corresponding US mode D and CEUS mode E. Quantitative analysis of the mean intensity in B mode F and CEUS mode G at different time points (n = 3, t test, *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001)