Automated time-domain determination of tissue viscoelasticity in a sub-hertz frequency range

A system for ultrasound imaging of a compressed target object, the system comprising:

• a compression device, the device configured to apply a compression force to the target object,
• wherein the compression device is configured to increase the compression force with a constant ramp time from an initial value to the final predetermined value, and, once the final predetermined value has been reached, to maintain said compression force applied at a substantially constant level;
• an ultrasound probe including an ultrasound transducer, said probe mechanically coupled with the compression device and configured to receive an ultrasound wave from the target object in a time-window during which the compression device holds the ultrasound probe in contact with the target object and while said compression force is being applied to the target object;
• an ultrasound imaging system cooperated with the ultrasound probe and configured to record a sequence of ultrasound image data frames during the time-window, wherein the ultrasound image data frames represent a region of interest (ROI) of said target object;
• a compression device controller, operably cooperated with the compression device and including electronic circuitry programmed
• to set and control the ramp time, and
• to synchronize an operation of the compression device with an operation of the ultrasound imaging system;
• and
• a data-processing unit configured
• to receive signal outputs produced at least by the ultrasound imaging system and the compression device controller, said signal outputs representing the target object imaged with the ultrasound imaging probe while being compressed by the compression device, and
• to determine, based on said signal outputs, a spatial profile of a strain response of the target object to said compression force as a function of (i) time, and (ii) a viscoelastic retardation time characterizing the target object.