Detecting liver cracks using ultrasonic shear wave imaging
Jingfei Liu –
Texas Tech University
2500 Broadway
Lubbock, TX 79409

Popular version of 1aBAb – An ex vivo investigation of ultrasonic shear wave imaging for detecting liver cracks
Presented Monday morning, November 29, 2021
181st ASA Meeting
Click here to read the abstract

Liver crack is a type of liver trauma, in which a capsular tear of different geometries occurs due to external impacts, and it is a common physical damage in traffic accidents, combating sports, and other accidents. Since liver crack is an important source of morbidity and mortality in emergency medicine, a timely and accurate detection of the crack location and geometry is highly demanded. In current emergency care, ultrasonography, although has a low accuracy, is mostly used for initial examination of liver trauma due to its immediate availability, high mobility, and nonionizing nature. After the initial screening using ultrasonography, a more accurate diagnosis is normally achieved by X-ray computer tomography (CT). Although CT can provide more details of the liver damage, it is not easy to access because patients must be transport to CT facilities, and it is even risky for the patients like newborns whose condition is unstable. To develop a diagnostic technique which both has easy access and can provide accurate diagnosis, ultrasonic shear wave imaging was proposed in this study as a better option.

In this technique, shear wave, a different type of ultrasonic wave from the ultrasonic wave (longitudinal wave) used in typical ultrasonography, is first generated at the patients’ liver, and then tracked during its propagation. Because shear wave cannot propagate in blood, there will be strong reflection or diffraction at the crack locations, which ultrasonography cannot identify (because longitudinal wave can go through blood and no strong reflection is available). Thus, the location and severeness of targeted liver crack can possibly be detected.

In this study, the feasibility and effectiveness of this method was investigated in an ex vivo scenario. A porcine liver with cracks of different geometries was tested. Shear waves were generated using acoustic radiation force impulse and recorded using ultrafast ultrasound imaging. To find the best way to display the cracks, different methods of signal processing based on time-of-flight, shear wave modulus, and accumulated shear wave path were applied to the shear wave displacement extracted. The results show that shear wave imaging is a more sensitive method than the conventional ultrasonography in detecting liver cracks.

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