Differential Tissue Harmonic Imaging (D-THI)

Previous technology reduced imaging artifacts by detecting the second harmonics generated by nonlinear effects. However, since the second harmonics are high-frequency signals limited to a narrow frequency band, the sensitivity and image resolution are low, resulting in body surface examinations.

To overcome this problem, Canon developed Differential Tissue Harmonic Imaging (D-THI) which simultaneously transmits two types of ultrasound waves with different frequencies and creates a composite wave of the second harmonic and the differential harmonic (as well as the second harmonic) generated by the nonlinear effects in the received waveforms. This composite waveform consists solely of the reflected wave components due to nonlinear effects and achieves a wide bandwidth from low to high frequencies.

As a result, high-resolution images with good sensitivity can be acquired in both superficial and deep regions while retaining the advantages of conventional diagnostic ultrasound technology, such as fewer image artifacts.