What is ultrasound?
Ultrasound was introduced into medical practice in the 1950s. The technology has improved significantly since its introduction and it is now the primary imaging technique used in gynaecological (and obstetric) practice.
Ultrasound has gained rapid acceptance because it is a minimally invasive procedure with no radiation exposure. Ultrasound imaging is generally easy to perform, the equipment available in most medical institutions or practices and generally not costly.
Ultrasound works by transmitting high frequency (2000-5000 Hz) sound waves through the transducer. The transducer then listens for those returning echoes coming from the tissues inside your body.
- Bouncing the sound waves into the body.
- A receiver picking up the returning waves.
- The data being translated by a computer.
Transvaginal ultrasound waves
Transvaginal and transabdominal ultrasound probes
Transabdominal ultrasound waves
Ultrasound looks at soft tissue organs but is unable to evaluate the intestines or bone
Portable ultrasound machine
The ultrasound machines vary in size. Some cannot be moved very easily and others are small and very portable. Generally, the large the unit, the higher the resolution of the images obtained.
Non-portable ultrasound machine
Abdominal and transvaginal probes are used most commonly in gynaecology.
A transvaginal ultrasound probe works the same way as the abdominal probe does but it’s long and thin. It is generally a higher frequency probe which means that it generates images of a higher resolution and is closer to the uterus and ovaries once inserted into your vagina.
2-dimensional ultrasound (2-D U/S) of the pelvis is by far the most commonly used imaging method in gynaecology and this applies equally to the investigation of pelvic floor dysfunction.
3-D and 4-D images can now be produced with specialized transducers and computer rendering. These allow access to the axial plane, a necessity for assessment of the levator ani muscles. 4-D U/S provides real time acquisition of volume ultrasound data.
Although the information being produced from 3-D and 4-D ultrasound is providing more insight into pelvic floor anatomy and function, the translation into clinical management has not yet occurred.
Endoanal ultrasound schematic
Endoanal ultrasound is considered to be the gold standard imaging technique for detecting anal sphincter damage.
Perineal and translabial approaches are newer developments that are currently used more for research and assessment of pelvic floor anatomy and function but their place in clinical practice has not yet been established.
Preparation for your ultrasound scan
You can eat as normal prior to your scan. Transabdominal ultrasounds to assess the pelvis, lower abdomen, kidney or bladder require you to have a full bladder. Having a full bladder can be quite intimidating for some women. It is necessary to drink 1 litre of water one hour prior to the scan and refrain from from going to the toilet. For transvaginal scans you will be asked to empty your bladder prior to the investigation. If you haven’t ever been sexually active then a vaginal ultrasound is not usually performed.
The sonographer or radiologist will ask you to lie on a couch.
The area of your lower abdomen and suprapubic area will be exposed. There will be no requirement to remove your clothes but you will need to move them out of the way so that gel can be applied. The abdominal transducer is then placed and moved around the lower abdominal wall.
The vaginal ultrasound probe will be covered with a condom and will have been soaked in a disinfectant between uses. The ultrasound probe will be covered in gel. The sonographer will insert the probe, or ask you to do it. After taking all the necessary images the probe will be removed.
In most cases you will not feel any pain during the scan. However, if your scan is for abdominal pain or you have vaginal pain/discomfort then you may experience some discomfort.
If you find the examination difficult or uncomfortable, please tell the sonographer. An ultrasound scan usually takes 10 – 20 minutes, depending on the area of your body that is being scanned.
- In most cases, you will be allowed to go straight home.
- You can eat, drink and go back to your normal activities straight away.
- The results will be sent to the doctor who referred you.
It is the sonographer’s duty to perform the test and ensure the images are of high quality.
It is the radiologist and your referring doctor’s duty to interpret the images.
It is your referring doctor’s duty to discuss the results with you.