A basic study of ultrasonic shear wave elastography in tissue-mimicking phantoms

Since many diseases cause changes in the mechanical properties of soft tissues, it is of interest to image their elasticity. Detection of tumors in early stages is challenging but paramount for the proper treatment of patients and thus to reduce the mortality rate. Elasticity imaging (elastography) has great potential to improve tumor diagnosis and is being developed and tested by several research groups with ultrasound and magnetic resonance imaging (MRI). As opposed to MRI, medical ultrasound is widely available, much more cost-effective and most of all a real-time imaging modality. In this paper we evaluate ultrasonic shear wave elastography, a dynamic approach to determine soft tissue properties. Our feasibility study using tissue-mimicking phantoms demonstrates that low frequency shear wave oscillation amplitudes in the micrometer range can be measured using commercial ultrasound scanners in combination with a particular signal processing method. Stiff tissue regions (tumors) show smaller shear wave amplitudes than the surrounding normal tissue. Not only can the examination time be reduced from about 10-20 minutes (MRI) to a few seconds, it may also soon be possible to detect certain cardiovascular dysfunctions in real-time using ultrasonic shear wave elastography.