Use of a Real-Time Stress Map for Assessment of Applied Stress for Strain Elastography: Utility in Training and Computation of Strain Ratios.

Abstract

There is a significant learning curve in strain elastography. Uniform appropriate levels of stress must be applied for accurate elastograms. If the stress is not applied appropriately, inaccurate results will be obtained, particularly when strain ratios are being estimated. This paper describes a new technique which allows the real-time visualization of the applied stress with a color-coded stress map. The potential use of this map is discussed. Ten patients (5 breast, 5 thyroid) and phantoms were scanned using the stress map. The stress applied was varied and the resultant change in the strain image evaluated. The stress map was able to document if appropriate stress was applied when performing strain elastography. When inappropriate stress was applied or physiological process effected the strain image the stress map demonstrated the areas of inaccurate measurements in the stress map. The display of a stress map that depicts the degree and uniformity of applied stress would be helpful both for training of the appropriate technique, for confirming that the elastogram is appropriate for evaluation, and that strain ratio estimates are accurate.