Obstetric ultrasound refers to the specialised use of ultrasound to visualise and determine the condition of a pregnant woman and her embryo or foetus.
Some indications for obstetric ultrasound may be:
Ultrasound has been widely used to evaluate pregnancy for more than 30 years and there has been no evidence of any harmful effects to the patient, embryo or foetus. However, ultrasound should only be used where clinically indicated.
PHOTO: Ultrasound showing nuchal translucency measurement (skin fold at the base of the neck of the foetus) at 11 weeks gestation
Obstetric ultrasound cannot identify all foetal abnormalities. Consequently, when there are clinical or laboratory suspicions of a possible abnormality, a pregnant woman may have to undergo non-radiological testing such as an amniocentesis (the evaluation of fluid taken the sac surrounding the embryo or foetus) to determine the health of the embryo or foetus. An ultrasound for nuchal translucency evaluation involves measuring the skin fold on the back of the neck of the foetus between 11-14 weeks of pregnancy. An increased measurement has shown to be related to an increased risk of chromosomal abnormality and nuchal translucency assessment may be useful in determining whether or not amniocentesis or other testing is appropriate.
Compared to traditional 2 dimensional ultrasound images 3D and 4D ultrasound can allow the features of the unborn baby to be seen in more detail. Rather than simply showing the size and shape of the foetus, 3D images can show the unique facial and anatomical features of the baby.
The 4th dimension in 4D scanning is time, or motion. 4D ultrasound is moving 3D images. 3D ultrasound technology is useful for assessing foetal abnormalities such as cleft lip or club feet. The addition of 4D can greatly assist in the assessment of the foetal heart and movement. It can also demonstrate foetal behaviour such as yawning and eye opening.
The best time for obtaining optimum images of the baby is around 26-30 weeks, as this is the time where the baby has some subcutaneous fat, is still relatively high in the uterus and there is plenty of amniotic fluid surrounding it. The clarity of the images will depend on the position of the foetus and the placenta and the volume of fluid around the foetus.
3D and 4D has many other clinical applications beyond obstetric ultrasound, and may be used to assess anatomical structures and refine the diagnosis of many medical conditions.
See the Information Sheets tab for further information on 3D/4D scanning during pregnancy.
An ultrasound image is a useful way of examining the musculo-skeletal system of the body to detect problems with muscles, tendons, joints and soft tissue, and may enable a radiologist to diagnose a variety of conditions and assess damage after an injury.
Ultrasound is commonly used in diagnosing tendon tears, such as tears of the rotator cuff in the shoulder. Abnormalities of the muscles can also be seen such as tears and soft tissue masses. Bleeding or other fluid collections within the muscles, bursae and joints can also be detected. Ultrasound is generally not useful in detecting whiplash injuries or other causes of back pain.
PHOTO: Normal appearing right
shoulder ultrasound showing the biceps, subscapularis and supraspinatous tendons
Ultrasound is commonly used to guide the injection of steroid and anaesthetic into joints for the relief from pain for many longstanding musculo-skeletal conditions and injuries.
It is also used to guide procedures such as needle biopsies and aspirations of abdominal organs. Abdominal ultrasound can help determine the cause of abdominal pain, such as stones in the gallbladder or kidney.
It can also help identify the cause for the enlargement of an abdominal organ, and detect the growth of tumours within the abdomen.
PHOTO: Normal upper abdominal ultrasound showing pancreas, liver, gall bladder and kidneys
For women, pelvic ultrasound is most often used to examine the uterus and ovaries, and during pregnancy, to monitor the health and development of the embryo or foetus. In males, a pelvic ultrasound usually focuses on the bladder and the prostate gland.
For females, pelvic ultrasound examinations can help determine the causes of pelvic pain, abnormal bleeding, or other menstrual problems. Ultrasound images can also help to identify and assess cysts and fibroid growths as well as ovarian or uterine cancers. Female pelvic ultrasound is also used to monitor and assess the development of follicles in patients undergoing fertility treatment.
Sometimes the radiologist may determine that a transvaginal scan needs to be performed. Instead of a transducer being moved across the abdomen, the high-frequency waves are emitted by a probe (endovaginal transducer) placed in the vagina. This technique often provides improved images of the uterus and ovaries, and can be especially useful in early pregnancy.
For males, pelvic ultrasound is a valuable tool for evaluating the prostate gland.
In both sexes, pelvic ultrasound can help to identify tumours and other disorders in the urinary bladder. The pelvis houses some of the largest blood vessels in the body, and ultrasound can be used to evaluate blood flow in these vessels.
Ultrasound is a useful modality for evaluating the body’s circulatory system. Because ultrasound images are captured in real-time they can help radiologists monitor the blood flow to organs and tissues throughout the body, as well as evaluate the placement and success of repair, such as arterial bypass surgery. With ultrasound images, radiologists can locate obstructions (stenoses) and abnormalities such as blood clots, plaque or emboli. With the knowledge about the arterial blood flow gained from an ultrasound, the radiologist can often determine whether a patient is a good candidate for a procedure such as angioplasty.
Ultrasound of the vascular system also provides a fast, non-invasive means of identifying blockages of blood flow to the brain that might produce a stroke or mini-stroke.
When a blood clot develops inside a vein, ultrasound can show the clot and also the slowing down or complete block of blood flow that it causes. The most common reason for a venous ultrasound is to detect such clots, especially in the veins of the leg. These clots may break off and pass into the lungs where they can cause a dangerous condition called pulmonary embolism. If detected in time, treatment can prevent this from happening.
Other indications for a venous ultrasound study include finding the cause of long-standing leg swelling. Venous ultrasound may help a surgeon decide how best to deal with patients with varicose veins. It can also map out the veins in the leg or arm so that segments may be removed and used to bypass an area of disease.
Venous ultrasound is non-invasive very often eliminates the need for venography, which requires the injection of contrast material into a vein to detect a clot.
View a project milestone video of our new building which is nearing completion.