Ultrasound is one of the most widely used imaging tools in medicine, and yet many people associate it only with pregnancy scans. In reality, diagnostic ultrasound is used to examine a huge range of areas throughout the body, from joints and tendons to internal organs and blood vessels. It's quick, painless, and completely free of radiation, which makes it a valuable first step for investigating many different symptoms.
This guide explains what a diagnostic ultrasound is, how it works, what it can show, and what to expect from a scan at Momentm Health in Cambridge.
What is a diagnostic ultrasound?
A diagnostic ultrasound is a scan that uses high-frequency sound waves to produce images of the inside of your body. A small handheld device called a transducer or probe is moved over the skin, sending sound waves into the body and picking up the echoes as they bounce back off different structures. A computer converts these echoes into a live, moving image on a screen.
Because it works with sound rather than radiation, ultrasound is considered very safe, which is one of the reasons it's used so widely, including during pregnancy. It's also fast and well tolerated, with no injections or preparation needed for many types of scan.
How does ultrasound work?
The principle behind ultrasound is straightforward. Sound waves travel at different speeds through different tissues, and they reflect back in different ways depending on what they meet, whether that's fluid, soft tissue or bone. The scanner interprets these returning echoes to build a detailed picture.
One of ultrasound's biggest advantages is that it works in real time. Rather than a single still image, it shows movement as it happens, which means a clinician can watch how a structure behaves. This is particularly useful for assessing tendons and muscles as a joint moves, or for observing blood flow through a vessel.
What can a diagnostic ultrasound show?
Ultrasound is remarkably versatile. Some of the most common uses include:
- Muscles, tendons and joints. Ultrasound is excellent for examining soft tissues, helping to identify tendon injuries, inflammation, tears and other musculoskeletal problems. Because it images in real time, structures can be assessed as they move.
- Abdominal organs. It's widely used to look at organs such as the liver, gallbladder, kidneys, pancreas and spleen, helping to investigate pain, assess function and detect abnormalities.
- Blood vessels. Specialised ultrasound can assess blood flow and check for narrowing or blockages in vessels.
- Small parts. Areas such as the thyroid, and lumps or swellings close to the skin's surface, can be examined in detail.
- Guiding procedures. Ultrasound is also used to guide injections and other procedures, allowing a clinician to see exactly where a needle is going for greater accuracy.
Because it covers such a wide range of areas, ultrasound is often one of the first scans used to investigate a symptom, and it can help determine whether further imaging is needed.
Ultrasound and MRI: how they differ
Ultrasound and MRI are both excellent at imaging soft tissue, and they're often complementary rather than competing. Which one is most appropriate depends on what needs to be examined.
Ultrasound is quick, comfortable and shows movement in real time, which makes it ideal for many tendon and soft tissue questions, as well as for looking at certain organs. MRI, by contrast, provides a highly detailed, comprehensive view of both soft tissue and deeper structures, including inside joints and bone, in a way ultrasound cannot.
In practice, a clinician will recommend whichever scan is best suited to your symptoms, and in some cases the two are used together to build a fuller picture. The aim is always to choose the imaging that answers the clinical question most clearly.
What to expect from your scan
A diagnostic ultrasound is a simple and comfortable procedure. Depending on the area being examined, you may be asked to remove clothing from that part of the body, and for some scans there's a little preparation involved, such as not eating beforehand for certain abdominal scans. Your appointment details will explain anything you need to do in advance.
During the scan, a clear gel is applied to the skin. This might feel slightly cool, and it helps the probe make good contact and produce a clear image. The clinician then moves the probe over the area, viewing the images on a screen as they go. The scan is painless, although there may be some mild pressure as the probe is moved.
Most ultrasound scans take somewhere between 15 and 45 minutes, depending on what's being examined. There's no recovery time, no radiation, and you can drive and carry on with your day straight afterwards.
Frequently asked questions
Is a diagnostic ultrasound safe? Yes. Ultrasound uses sound waves rather than ionising radiation, and it's considered very safe. It's the same technology used routinely in pregnancy, which reflects how well established its safety is.
Does an ultrasound scan hurt? No, ultrasound scans are painless. You may feel some light pressure as the probe is moved over the skin, and the gel can feel slightly cool, but the scan itself is comfortable.
Do I need to prepare for an ultrasound? It depends on the type of scan. Some abdominal scans require you to avoid eating for a period beforehand, while many musculoskeletal scans need no preparation at all. We'll give you clear instructions when you book.
Ultrasound or MRI, which do I need? That depends on what's being investigated. Both are excellent for soft tissue, but MRI gives a more detailed view of deeper structures and inside joints, while ultrasound offers a quick, real-time view that's ideal for many tendon and organ questions. A clinician can advise on the most suitable scan.
Do I need a referral for an ultrasound? For our core scans you can book directly with Momentm Health without a referral, though we're happy to work with one from your GP or another clinician if you have it.
How long does an ultrasound take? Most scans take between 15 and 45 minutes, depending on the area being examined.
Diagnostic ultrasound at Momentm Health in Cambridge
If you have a symptom you want investigated, a diagnostic ultrasound can often provide answers quickly and comfortably. At Momentm Health, ultrasound scans are carried out by experienced clinicians and overseen by an expert consultant team, so you can be confident in the quality of both the scan and its interpretation.
Our Cambridge clinic offers fast access with no long waits, and for our core scans you can book directly without a referral.
Book a scan, or get in touch to find out more about ultrasound at Momentm Health.
Ultrasound forms one part of investigating a symptom. The most appropriate scan and any next steps are determined alongside a clinical assessment.
