Contrast Harmonic Imaging

Ultrasound contrast harmonic imaging (UCHI) is a medical imaging technique that combines ultrasound waves and contrast agents (microbubbles) to produce detailed images of internal organs and blood vessels with improved resolution and contrast. The technique utilizes systemically injected microbubbles, which are excited by the ultrasound waves and produce harmonic frequencies that are different from the fundamental frequency of the ultrasound waves. These harmonic frequencies are then used to enhance the imaging of the microbubbles by separating their echoes from the linear-like surrounding tissue.
We are developing advanced techniques to improve UCHI by triggering a robust frequency mixing effect within the microbubbles. This increases the nonlinear content emitted by the microbubbles, resulting in improved image contrast. One such technique is the use of a dual-frequency waveform, which triggers a frequency mixing effect within the microbubbles’ backscattered echoes, generating the sum and difference frequency of the two transmitted frequencies, in addition to their harmonics. The presence of additional nonlinear components amplifies the microbubbles’ signal, leading to an increase in the resulting harmonic image quality and contrast. Additionally, by using a broadband transducer, it is possible to include both the difference and sum frequencies, further improving image contrast.