Abstract:

BACKGROUND: After focused ultrasound irradiation, focused regional organizations will form the strong echo phenomenon in the corresponding position of the B-mode images, which may form acoustic impedance difference in the soft tissue and may disrupt the damage detection.
OBJECTIVE: To propose an imaging method based on the empirical mode decomposition and subtraction method for the detection of tissue lesion induced by high intensity focused ultrasound.
METHODS: Combined the advantage of empirical mode decomposition with that of subtraction method, ultrasonic echo signal was decomposed adaptively by empirical mode decomposition method, and then, subtraction method was executed to the denoised. Finally, monitoring image of lesions was completed after Hilbert transformation and log conversion.
RESULTS AND CONCLUSION: The experiments of bovine liver in vitro were implemented. The differential images combined with the empirical mode decomposition were acquired as well as corresponding B-mode images and the differential images. The results of experiment showed that the proposed method can characterize the high intensity focused ultrasound induced lesions in soft tissue effectively. It can identify the smaller lesions which can not be detected in B-mode images and offer higher contrast and resolution than that of the differential images.