Tissue characterization from ultrasonic imaging of movement and deformation

A technique was developed for detecting and imaging local displacement of soft tissues. Measurements were performed in vivo using a conventional real-time linear array transducer with a 3.5-MHz center frequency, and the sequence of B-scan images was digitized to compute the two-dimensional map of tissue movement. Preliminary experiments indicate that a local tissue movement of less than 0.3 mm/0.06 s was estimated with a spatial resolution of 3 mm×3 mm. The local movement was larger in more elastic regions. It is suggested that decreased mobility as well as hardening of soft tissue due to tumor or fibrosis may be characterized from the local movement observed in conventional real-time B-scan images