Ultrasound imaging is a non-invasive, painless medical imaging examination that uses high-frequency sound waves to produce cross-sectional images.
Ultrasound is used extensively during pregnancy, and to assess many organs and superficial parts, as well as the heart and blood vessels. Areas of pain, swelling or infection can be directly assessed in real time. Because ultrasound is readily available and cost-effective, it is often the first diagnostic test your doctor orders for abdominal, pelvic and musculoskeletal pain. Not all causes of pain show on ultrasound so further testing may be required. Ultrasound does not involve ionising radiation, making it ideal for pregnant women and their babies and children.
Before your ultrasound
When you book your ultrasound appointment, our staff will advise you of any specific preparation, but here is a guide to assist you:
- Breast, thyroid, duplex carotid, leg veins: No preparation required.
- Abdomen: Please fast for six (6) hours – nothing to eat, drink or smoke during this period. Take your usual medications with a sip of water (no milk or soft drinks).
- Urinary tract (kidneys, bladder and ureters, plus prostate in men): Your bladder must be full at appointment time. Empty your bladder one (1) hour before your appointment, then drink one (1) litre of clear fluid or cordial. Do not empty your bladder before your appointment unless really necessary.
- Pelvis: Bladder must be full at appointment time. Empty your bladder one (1) hour before your appointment, then drink one (1) litre of clear fluid or cordial. Do not empty your bladder before your appointment unless really necessary.
If you have had to fill your bladder for an ultrasound, please advise our reception staff if you are feeling too uncomfortable, or feel you may have to empty your bladder very soon. While we make every attempt to avoid delays, occasionally we might have to make allowances for urgent cases and this could cause unintended delays for other patients and appointments.
The sonographer may ask you to change into a gown to avoid spoiling your clothes with gel. Once you are safely positioned on the ultrasound couch, the sonographer will dim the lights for better viewing. Special gel is used between the transducer and your skin, to enable optimal transmission of the sound waves. The transducer is moved over the area of interest. You may be asked to roll onto your side or take a deep breath to optimise the images. If you experience any pain during the scan because of your position or the pressure of the transducer, you should advise the sonographer.
During your ultrasound
If you’ve been referred for a pelvic, obstetric, or urinary tract ultrasound you will need to arrive with a full bladder. The sonographer will assess the areas best visualised with a full bladder first, ask you to go to the toilet to empty your bladder, and then continue with further imaging.
Are there any risks?
Since the 1980s, ultrasound has been extensively used throughout Australia and the world for medical imaging. The images are created when tissues at different depths reflect the ultrasound waves transmitted into the body, similar to radar used by boats and ships. At the intensities used for diagnostic medical purposes, no soft tissue damage has ever been observed in human or mammalian tissue. The sonographer will set the equipment to the lowest intensity necessary to achieve high quality images.
After your ultrasound
A radiologist will interpret your ultrasound images and provide your doctor or health care professional with a comprehensive report about the findings. You will need to return to him or her to discuss your ultrasound results. Processing and reporting of your ultrasound could take up to two hours. For your convenience we can generally deliver the images and report to your doctor by lunchtime on the next working day.
If you require the results for a follow up appointment on the day of the scan, you can wait for the films and we will fax or email the results to your doctor. Some of our referring doctors prefer that their patients wait for their films after the scan. You may arrange to collect the films at an alternative time, if you prefer that option.
Ultrasound provides useful information about you and your baby that enables appropriate antenatal care. Fetal size and heart rate are checked at all stages of pregnancy, as well as the maternal uterus, ovaries and cervix.
During the first trimester, your doctor may request an ultrasound to determine your pregnancy dating. If you are not sure of the date of your last menstrual period, a sonographer can measure the crown-rump length, which will determine how far along you are (gestational age). If you have had symptoms such as bleeding or pain during the first trimester, your doctor may request an ultrasound to determine whether the pregnancy is within the uterus in the correct position, or whether you might have miscarried.
During the second trimester, a morphology scan (18-22 weeks) is used to check fetal growth, numerous important organs such as the spine, heart, brain and kidneys, placental site, and amniotic fluid volume. During the morphology scan, the sonographer will check for signs of a possible genetic problem. Your uterus and ovaries are also checked. All Australian women are encouraged to have a morphology scan.
During the third trimester, your doctor may request an ultrasound to check the fetal position, placental appearance and site, how much fluid is around the baby, fetal well being and the baby’s growth compared with previous scans and your expected date of delivery.
Ultrasound can detect many, but not all, abnormalities. Demonstrating a fetal abnormality on ultrasound depends on many factors, including fetal age and fetal position at the time of the ultrasound, and the size and type of abnormality. Image clarity depends on the resolution of the equipment and how well the ultrasound can pass through the maternal abdominal wall. For example, image clarity is reduced when the mother’s abdominal wall is thickened due to obesity or scarred.
At The Women's Imaging Centre we employ experienced, qualified sonographers accredited with the Australian Sonographer Accreditation Registry, and invest in the latest equipment to ensure you receive the very best patient care. Our staff use ultrasound with care to ensure that you and your baby benefit from what ultrasound offers, with minimum risk.
Advanced obstetric ultrasound is available, including 4D imaging in the 3rd trimester. Our pregnant patients have the option of choosing an additional 4D study when they attend for a diagnostic 3rd trimester ultrasound. This study can only be performed between 24 and 32 weeks when the fetal head is still high in the uterus, there is sufficient amniotic fluid surrounding the face; and when there is enough subcutaneous fat in the baby’s face. Extra time is allowed for this study and the patient is invited to bring family members to view the 4D real-time movement of the baby. The patient will also be given a CD of images.
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