Ultrasound phantom-free regularized local attenuation imaging

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Clinical ultrasound imaging provides different imaging modes for the purpose of diagnosis and therapy follow-up. Gray-scale B-mode imaging gives anatomy information, Doppler modes are used for measuring flow and tissue motion, and elastography modes allow assessing the mechanical property of tissues. Very recently, major ultrasound radiology manufacturers started releasing speed of sound, attenuation, and backscatter packages for tissue characterization and imaging. Those imaging modes enter into the category known as "quantitative ultrasound" (QUS) imaging, which aims providing a signature of a fundamental physical property of a tissue based on its interaction with propagating ultrasound waves. This application aims to further develop one of these QUS imaging methods, namely the quantification of the local attenuation known to change with pathology. The field of QUS imaging specifically aims to provide sub-resolution characteristics of acoustic scatterers or cells for the purpose of biological tissue characterization. One drawback of some of these methods is the requirement of a calibration phantom measurement to compensate for confounding effects of scanner and wave interaction characteristics with the insonified tissue. In this proposal, a phantom-free regularized local attenuation measurement method is proposed for applications in diagnostic imaging of liver diseases. The theoretical framework of the method relies on the assumption of similar wave diffraction effects at different frequencies within the bandwidth of the transmitted compression wave. Validation of the proposed imaging method will rely on computer simulations, in vitro gel phantom experiments and processing of clinical radiofrequency images. Robustness will be assessed by considering various conditions of background noise, homogeneous or heterogeneous tissues, attenuation contrasts, and presence or not of an inclusion (tumor) with different tissue characteristics. Ground truth measurements will be available for comparison with the proposed imaging method. Technological innovations will be made in line with product development priorities of our industrial partner, Siemens Healthcare.