Hello and welcome to the forum. Thank you for the question although this sounds like a stressful time for you. Your doctor is the best source of information but we will try to help. An automated breast ultrasound is done when there is a suspicious area that they want more images of. They literally can get hundreds of images this way. So, it sounds like that with your breast density, they may have worry that they could miss something and are wanting to make sure. This is a positive as that is how they can detect and treat a problem. Eve though I know it is scary. Have they stated you have a mass? When they talk about shadowing artifacts, it is usually in relation to a mass and helps them determine the nature of it. https://pubmed.ncbi.nlm.nih.gov/3514956/ When do you go back for follow up?