Ultrasound is a non-invasive imaging modality based on transmitting ultra-high frequency sound waves into the body and then receiving the returning echoes. Doppler technology was incorporated to detect moving structures such as blood within the body. 3D imaging with ultrasound is now possible and in use today.
In order to detect fine structures within the body, very high frequency sound waves must be used. The frequencies in today's ultrasound machine range from 2 Megahertz to 15 Megahertz. The sound is concentrated into a thin beam and directed into the patient by a hand held transducer. That same transducer also acts as a receiver. The sound waves enter the body and bounce off internal structures. The returning echoes are recorded and processed by a computer and converted into an image.
The Doppler principle is used to detect moving objects. Doppler ultrasound examinations allow for the detection of blood flow and the determination of the speed and direction of the flow.
Preparing for Your Exam
Some of Ultrasound and Segmental Doppler studies require specific instructions. Your doctor will inform you of these preparations. You can also call the Imaging Center where your study will be performed and a technologist will advise you of the proper steps toward a successful exam.
Abdomen, Gallbladder: Do not eat or drink anything six hours prior to your exam time.
Pelvic Ultrasound: You need a full bladder - do not empty your bladder two hours prior to your appointment time. One hour prior to your exam, drink at least 32 ounces of fluid. Do not empty your bladder. No fasting is necessary.