Services » Ultrasound
What is an Ultrasound scan?
Ultrasound scanning involves exposing part of the body to high-frequency sound waves to produce pictures of the inside of the body. Ultrasound exams do not use ionizing radiation (as used in x-rays). Because ultrasound images are captured in real-time, they can show the structure and movement of the body's internal organs, as well as blood flowing through blood vessels.
Ultrasound imaging is a non-invasive medical test used to help in the diagnosis and treatment of medical conditions.
Conventional ultrasound displays the images in thin, flat sections of the body.
A Doppler ultrasound study may be part of an ultrasound examination. Doppler ultrasound is a special ultrasound technique that evaluates blood as it flows through a blood vessel, including the body's major arteries and veins in the abdomen, arms, legs and neck.
There are three types of Doppler ultrasound:
- Colour Doppler uses a computer to convert Doppler measurements into an array of colours to visualise the speed and direction of blood flow through a blood vessel.
- Power Doppler is a newer technique that is more sensitive than colour Doppler and capable of providing greater detail of blood flow, especially when blood flow is little or minimal. Power Doppler, however, does not help the radiologist determine the direction of blood flow, which may be important in some situations.
- Spectral Doppler. Instead of displaying Doppler measurements visually, Spectral Doppler displays blood flow measurements graphically, in terms of the distance travelled per unit of time.
Ultrasound scans include:
- Upper Abdomen
- Kidneys, prostate and bladder
- Scrotum and testes
- Female pelvis
- Pregnancy including nuchal scanning at 11 - 13 weeks, morphology scans at 19 weeks and 3rd trimester scans
- Arteries, including carotids, renal, upper and lower limbs
- Veins - duplex assessment of leg veins
- Musculoskeletal scans - joints, tendons and ligaments.
- Ultrasound-guided injections
- Fine needle Aspiration (FNA) and biopsies
- Thyroid scans
- Assessment of superficial or palpable lumps
Is Ultrasound safe?
For standard diagnostic ultrasound there are no known harmful effects on humans.
Is there any preparation?
You should wear comfortable, loose-fitting clothing for your ultrasound exam.
You will need to remove all clothing and jewellery in the area to be examined. You may be asked to wear a gown during the procedure.
Other preparation depends on the type of examination you will have. For some scans your doctor may instruct you not to eat or drink for up to 6 hours before your appointment. For others you may be asked to drink a large glass of water one hour prior to your exam and avoid urinating so that your bladder is full when the scan begins.
What will happen to me?
For most ultrasound exams, you will lay face-up on an examination table.
A clear gel is applied to the area of the body being studied to help the transducer make secure contact with the body and eliminate air pockets between the transducer and the skin. The sonographer (ultrasound technologist) or radiologist then presses the transducer firmly against the skin and sweeps it back and forth over the area of interest.
Most ultrasound examinations are completed within 30 minutes to an hour.
Doppler sonography is performed using the same transducer.
In some ultrasound studies, the transducer is attached to a probe and inserted into a natural opening in the body. These exams are only performed after your consent, and include:
Transrectal ultrasound. The transducer is inserted into a man's rectum to view the prostate.
Transvaginal ultrasound. The transducer is inserted into a woman's vagina (usually by the patient herself) to view the uterus and ovaries.