Development of a stiffness measurement accessory for ultrasound in breast cancer diagnosis

When ultrasound imaging is used for breast cancer diagnosis, the lesion's morphology is usually used to determine if the lesion is benign or malignant. Sometimes, the information provided by the procedure may not be adequate to make an accurate judgment. Additional information is needed, such as the stiffness of the lesion relative to its surrounding tissue. This paper presents an ultrasound accessory device designed to achieve this purpose. The device is easy to operate and is similar in use to a normal clinical breast ultrasound examination. A sonologist must only attach an ultrasound probe to the device and then slide it across the lesion maintaining a constant compression depth. The built-in inverse biomechanical model of the device will then calculate the predicted stiffness ratio of the lesion relative to its surrounding tissue based on the measured palpation data. Modelling and experiments have been performed on phantoms with embedded inclusions. The experimental results show that the stiffness ratio of the inclusion to its surrounding material can be accurately predicted by the handheld device. A preliminary clinical test was also performed to demonstrate the use of this device in vivo, to offer additional information to aid classification of the tumor as benign or malignant when complemented with ultrasound images.