Color Doppler to Characterize Malignant Breast Lesion

Abstract

Doppler ultrasound is an important non-invasive diagnostic tool for identifying breast diseases. Ultrasound utilizes spectral Doppler techniques for quantitative evaluation of blood flow velocities, and these measurements play a crucial role in the diagnosis. In this paper, we describe a computer vision approach to automate the Doppler malignancy estimation. We present a technique for segmenting blood vessels in ultrasound color Doppler images based on image processing techniques. The technique decomposes a complex object representing either two or more vessels artificially linked together or a main vessel with its branches. We segment out the blood vessels in ultrasound color Doppler images and count the number of vessels to detect breast malignancy. MATLAB has been used to simulate the algorithm and the results obtained are presented in this paper. The result represents distinct vessels that can be used in further object recognition and quantification applications. In the last two decades of the twentieth century, a combination of modern treatment methods and strategies for early detection through screening and better public awareness, have improved survival of breast cancer despite a worldwide rise in its incidence. Different macro imaging like X-Ray mammography, Sono-mammography and Breast MRI play a major role in detection. Sono-mammography is a promising one among them for it is non-invasive and also cost effective for mass screening. Ultrasound imaging systems offer two main image types- gray-scale images and color Doppler images, each of which has its own clinical usage. Gray-scale images are used to visualize the anatomy of different body organs, while color Doppler images are used to visualize the blood flow (1) within the organs. Both images are used simultaneously for diagnosis as shown in Figure 1. To improve the accuracy of USG, additional techniques like Doppler imaging can be used. Doppler ultrasound technique is associated with reflection of continuous ultrasound waves. When an interface has back and forth movement, the transmitter and receiver frequency of the reflected ultrasound wave decreases or increases respectively. Doppler Effect refers to a change in the perceived frequency of sound emitted by a moving source. Doppler machines have the capability to note down the frequency changes. Doppler Effect in reflected wave gives information about the motion of the tissue interfaces. Transducers used for Doppler instruments consist of double-crystal, one transmitter and another receiver. Transmitter generates continuous ultrasound beam and they have no or very little damping material inside. Quantitative blood flow measurement can be done using this technique and it produces 2D images of region where blood-flow or tissue movement is occurring. The cost of this instrument is also very low.