study Guides Q A Lesson Plans Essay Editing Services. He is also a head of the community kickboxing group. Another type of ultrasound is Doppler state ultrasound, unlike hypothesis a standard ultrasound, sometimes called a duplex study, used to show the speed and direction of blood flow. Literature Essays College Application Essays Textbook Answers Writing Help. Written and edited by Harvard students. Log in Log in with Facebook GradeSaver offers the highest quality study guides. Some sound waves during the Doppler exam are audible.