In the UltraVision, elastography is performed in an optional additional, very large Field Programmable Gate Array printed circuit board. Elastography is performed with a two dimensional kernel on the RF data. This is normally set to 4096 axial samples and 128 lateral acoustic lines but these are user selectable. The UltraVision produces Sample Data of axial and lateral displacement and the cross correlation value at each data point. The General Purpose Graphics Processing Unit in the PC’s display further processes the Sample Data by differentiation and filtering to form strain images at up to hundreds of frames per second.

The images shown here were produced between adjacent frames at 120 frames per second. Functions are supplied that allow selections of multiple frames to be acquired from a push. The images shown are:

• Left: B-Scan image of 3 times harder inclusion in P.V.A. phantom
• Left Middle: Axial Strain
• Right Middle: Lateral strain
• Right: Non complex cross correlation value. This shows reduced correlation at 1/2 spaces of 10 micron shift isocontours
• The Far Right: part of the control panel indicating the chosen parameters

Elastography can also be performed, without the additional FPGA option, by the acquisition of the RF or Sample Data from several frames and then performing cross correlation in the PC. However, this is not a real time process due to the complexity of the cross correlation and time required by the PC to perform the algorithm.