The scan uses high-frequency sound waves to produce images of soft tissues, such as infection, injury, and abnormal masses. Your doctor may advise this scan to evaluate infections, including cellulitis, abscess, and necrotizing fasciitis. It can also be recommended in the evaluation of cysts and lymph nodes. It is a valuable tool in detecting soft-tissue foreign bodies, including wood splinters, glass, metal, and plastic. Foreign bodies embedded in soft tissues can cause inflammation and allergic reactions.