Ultrasound image segmentation is strongly influenced by the quality of data. There are characteristic artefacts which make the segmentation task complicated such as attenuation, speckle, shadows and signal dropout; due to the orientation dependence of acquisition that can result in missing boundaries. Further complications arise as the contrast between areas of interest is often low. However, there have been recent advances in transducer design, spatial/temporal resolution, digital systems, portability etc that mean that the quality of information from an ultrasound (US) device has significantly improved.
(Noble., 2008) Ultrasound image segmentation: a survey. IEEE.