Fig. 2. The effect of pre-compression on stiffness values.

When pre-compression (added pressure on the breast with the transducer) is added, the stiffness value of the lesion will increase. It is important to only apply minimal pressure with the transducer. A-E. In this series of images, the lesion a benign fibroadenoma (A), its stiffness when done properly is 2.4 m/sec (B) as increased compression is added, the lesion stiffness increases to 3.0 m/sec (C), 3.79 m/sec (D), and 5.1 m/sec (E). Note also that the stiffness value of fat also increases with increased compression.