Manual Palpation of the body was presumably the earliest way to perform medical diagnostics. Nowadays this method is still used often and successfully – e.g. in orthopedics or in breast cancer diagnosis.The method's sensitivity to mechanical differences of tissue is strongly related to the experience of the performing physician and to the distance of the examined tissue to the body's surface area.

We developed a method to exploit ultrasound in combination with MRI as an “automatic sense of touch”. This should lead to a reproducible way to image the mechanical properties of tissue inside the body.

To achieve this, the tissue is exposed to ultrasonic waves of 2.5 MHz for 20 ms. This leads to a small displacement of the tissue during ultrasound application (acoustic radiation force), which not only depends on the ultrasound intensity (1 to 30 W/cm²) but also on the elastic properties of the tissue. A displacement sensitive MRI sequence is used to visualize and measure the displacement quantitatively. The gray values in the acquired phase images are used to calculate the tissue displacement during US application.