TABLE 2. Existing Elastography Using Other Types of Imaging.

Method	Procedure	Limitation
Magnetic Resonance Elastography [9]	•uses magnetic imaging to create a 3-D map of the tissue stiffness	•non clear contrast in resulting image
Tactile Imaging [8]	•translates the sense of touch into a digital image	•requires large vibration sensors that have long acquisition time
Optical Coherence Elastography [10]	•images are formed by mapping a mechanical property of the tissue	•low quality image due to speckle tracking
Phase Contrast Imaging [12], [13]	•images are formed by refraction of x-ray beams off of tissue structures	•lower contrast than external manipulation of tissue