1. A method for determining a distribution of a stiffness parameter across a volume of tissue, the method comprising: with a transducer comprising an array of ultrasound transmitters and an array of ultrasound receivers and configured to surround the volume of tissue, emitting acoustic waveforms toward the volume of tissue with the array of ultrasound transmitters; detecting, with the array of ultrasound receivers, a set of acoustic signals derived from acoustic waveforms transmitted through the volume of tissue; at a computer processor in communication with the transducer, generating, from the set of acoustic signals, a sound speed map of a region of the volume of tissue, the region including a set of elements; at the computer processor, generating, from the set of acoustic signals, an acoustic attenuation map of the region of the volume of tissue; at the computer processor, generating a stiffness map derived from combination of a set of sound speed parameter values of the sound speed map and a corresponding set of acoustic attenuation parameter values of the acoustic attenuation map, the set of sound speed parameter values and the corresponding set of acoustic attenuation parameters associated with the set of elements of the region of the volume of tissue, and the stiffness map representing the distribution of the stiffness parameter across the region, wherein generating the stiffness map comprises performing element-wise multiplication between values of the set of sound speed parameter values and values of the corresponding set of acoustic attenuation parameter values to generate a combined acoustomechanical parameter map; and at a display in communication with the computer processor, rendering a stiffness image of the volume of tissue, based upon the stiffness map, thereby characterizing stiffness for the region of the volume of tissue.