On ultrasound image reconstruction by tissue density estimation

An inherent property of medical ultrasound imaging is the speckle noise that generally obscures the image and reduces the diagnostic image resolution and contrast. Consequently, substantial improvement of ultrasound images is an important prerequisite for ultrasound imaging. Some recent research has suggested that the spatial distribution of tissue densities may be used in ultrasound imaging to reconstruct images with fewer speckles. This new approach is based on the direct estimation of tissue density from the radio frequency echo signals received by ultrasound probe. This paper presents a mathematical analysis of this approach and derives a simplified model for issue estimation. This model simplifies the computation involved in density estimation and provides deeper insight into the problem. It shows that image reconstruction by tissue density estimation may have limited effect on speckle noise embedded in the RF echo signal. The analysis results are verified by numerical calculations and simulation examples.