Combined Tissue Imaging Technique: Deconvolved Inverse Scattering Impedance Imaging with Account of the Second Harmonic Signal

Abstract

Ultrasound tissue harmonic imaging (THI) can greatly improve the diagnostic quality of images. While a large transducer bandwidth is necessary for this technique, the axial resolution is still limited in THI. Technological limitations for THI are also more pronounced at higher frequencies because of the small size of transducer. The depth of penetration is also less due to higher attenuation. Here we describe a new combined imaging technique: Born‐approximation deconvolved inverse scattering (BADIS) imaging and tissue harmonic imaging (THI). BADIS technique deconvolves the incident pulse from the reflected pulse, and uses the resulting impulse response to produce an image of the acoustic impedance distribution. These images are free of speckle and have improved axial resolution. BADIS allows the use of lower frequencies than those would be required by the pulse‐echo method to achieve the same axial resolution. To provide further improvement we took into account of the nonlinear properties of tissue and implemented the second harmonic signal generated due to this nonlinearity in BADIS technique. We obtained results of soft tissue imaging that demonstrated the improvement of the image quality in comparison with the common pulse‐echo imaging technique.