The aim of this paper is to introduce a Simulator of Echo Contrast Imaging (SECI) which simulates the entire process of echographic imaging with contrast agent. It gives the possibility, through a GUI (Graphical User Interface), to choose simulation parameters such as the contrast agent, the probe (especially size, geometry and central frequency), the imaging modality or the echoscanner tuning. The aim of SECI is to simulate the image, considering a particular configuration. This simulator was validated using a set of in-vitro experiments. A tissue mimicking phantom (ATS Lab) and a solution of Sonovue™ (Bracco Research). From there, concentrations and Mechanical Index (MI) were the varying parameters. In both the experimental and simulated data, two Regions Of Interest (ROI) at the same depth were selected, one inside the bubbles cloud, the other in the tissue. Then the Agent to Tissue Ratios (ATR) were calculated in those ROI. The ratio was computed using first the gray level of the image and then the power spectrum over a particular frequency window of the RF signal.