8 Feb, 2022

Ultrasound Scans: how do they work?

Ultrasound scans were first used in clinical practice in 1956, and are one of the most popular medical imaging techniques available today. Ultrasound technology has developed over the decades to enable external and internal scanning of organs, soft tissues, the musculoskeletal system (including muscles, tendons, ligaments and joints) and the vascular (circulatory) system. 

If you're suffering from pain and want to know the cause, or are hoping to gain insights into your health and how your body is functioning, booking a private ultrasound scan can help you find out what you need to know quickly and safely. 
 
How do ultrasound scans work?
 
Ultrasound imaging is also known as sonography because it uses high-frequency sound waves to capture images inside the body in real-time.
 
An ultrasound probe is called a transducer, and there are different types and sizes, which can be used either on the skin (externally) or within the body (internally).
 
The probe emits the ultrasound waves, which are reflected by soft tissues, fluid or bone within the body. The transducer then records the speed and timing of these echoes to generate real-time images, which can be viewed on a monitor during the scan.
 
💡 Humans can generally hear sounds up to 20KHz pitch, with dogs and cats able to hear up to 40KHz. Most ultrasound scans use much higher frequencies in the megahertz (MHz) range, which means they are so high-pitched they are inaudible to humans.
 
Usually, a thick gel is used on the skin for external ultrasounds, as it lubricates the area and prevents air pockets between the scanner and skin, which could affect the way the sound waves travel and reduce image quality.

What does an ultrasound scan show?

Ultrasound images are displayed in either 2D, 3D, or moving 4D images. The images are usually black and white, but there can be different shades of grey depending on the tissues scanned. Doppler ultrasound scans can produce graphs rather than images, and are used for measuring the rate of blood flow.
 
Ultrasounds are not always suited to organs that contain air, such as the stomach, lungs and bowels, because the ultrasound waves do not bounce off the structures very well. This means the echoes are harder to pick up and clear images cannot be produced.
 
Learn more about the types of ultrasound and the diagnoses they can confirm

Ultrasound scan uses

A key use for ultrasound is determining the composition of a lump, which allows doctors to assess whether it is a cyst or tumour. Cysts are fluid-filled and send back very few echoes, whereas tumours are solid and waves will bounce off of them. Ultrasounds can also show whether a tumour is benign or malignant (cancerous) by providing insights into the size, shape and location.

Ultrasound scans can be used on many different organs and soft tissues, including liver, gallbladder, pancreas, spleen, prostate, ovaries and eyes, along with other bodily structures such as joints and ligaments.

Enabling a view of these organs and internal structures can help doctors to diagnose and monitor many health conditions. Alongside tumours and cysts, these include gallstones, ectopic pregnancy, carpal tunnel syndrome, tennis elbow, and many more.

Are ultrasound scans safe?

Ultrasound scans are very safe, as they do not use harmful radiation like X-rays and CT scans do, and external ultrasounds are non-invasive and straightforward procedures.
 
Internal ultrasound scans such as transvaginal, transrectal and endoscopic scans do require more preparation, and sometimes sedation is offered for the process. This is mainly to alleviate discomfort, and is not related to the safety of the scan.

Do ultrasound scans have any side effects?

There are no side effects to ultrasound scans, but if you have had a sedative, you will require supervision for 24 hours afterwards, and you won't be able to drive or operate heavy machinery in this time.

Internal ultrasounds such as endoscopic scans may have side effects related to the use of the equipment, rather than the sound wave technology itself. This can include discomfort and a sore throat.


If you're struggling with undiagnosed pain or a health concern, an ultrasound scan can provide a clear picture of the cause of the problem. Speak to our team today to book your private ultrasound scan without GP referral.

Next steps:

Sources used

https://www.livescience.com/32071-history-of-fetal-ultrasound.html#:~:text=

https://www.nibib.nih.gov/science-education/science-topics/ultrasound

http://www.meddean.luc.edu/lumen/meded/urology/ushome.htm

https://patient.info/treatment-medication/ultrasound-scan

https://www.nhs.uk/conditions/ultrasound-scan/

https://www.webmd.com/a-to-z-guides/what-is-an-ultrasound

https://www.radiology.ca/article/how-does-ultrasound-help-determine-if-lump-concern

http://www.meddean.luc.edu/lumen/meded/urology/ushome.htm

https://www.mayoclinic.org/tests-procedures/ultrasound/about/pac-20395177

https://medlineplus.gov/lab-tests/doppler-ultrasound/
 
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