Improving the diagnostic potentiality of contrast enhanced ultrasound imaging through the estimation of the concentration

Next-generation ultrasound contrast agents, in the form of tiny gas bubbles, can be targeted to selectively adhere to cancer cells. The number of attached microbubbles could be correlated with the status of the cancer. Consequently, the estimation of bubble concentration can provide useful medical information in addition to ultrasound molecular imaging. In this paper, a method to obtain the ultrasound image of a region of interest and the estimation of the related microbubble volumetric concentration is proposed. The mentioned tasks are performed in an unique investigation, working on the signals remotely acquired by means of an ultrasound scanner. The algorithm is divided into two steps. Firstly, a signal processing technique, based on multi-pulse transmission and recombination of the received signals, is used to obtain an image of the scene and to detect the bubble echoes abating surrounding tissue contribution. Then, the residual bubble echo, remained after the application of the technique, is processed in order to estimate the concentration. The concentration estimation method is based on a nonlinear regression approach, carried out by a support vector machine. Preliminary in vitro experiments provided encouraging results.