Lymph node ultrasound: what it shows and what happens afterwards

Lymph nodes, often called glands, are small bean-shaped structures in the lymphatic system that help fight infection. They are found in the neck, under the chin, in the armpits and in the groin, among other places. The NHS says glands swell near an infection to help the body fight it and that swollen glands usually go down within 1 to 2 weeks.

An ultrasound scan uses sound waves to take pictures inside the body. Lymphoma Action explains that a probe makes high-energy sound waves, too high-pitched to hear, which bounce off tissues and create echoes; the probe records the echoes and a computer builds a picture. Because lymph nodes close to the surface are easy to reach with a probe, ultrasound is well suited to looking at them.

A GP or specialist may arrange an ultrasound when a lymph node is persistently enlarged, is hard, is growing, or when there is no obvious cause such as an infection. The NHS advises seeing a GP if swollen glands are getting bigger or have not gone down within 1 week, feel hard or do not move when pressed, come with night sweats or a very high temperature, occur with no other signs of illness, or are just above or below the collar bone.

Lymphoma Action states that an ultrasound scan may be done when a person has lymphoma or the doctor suspects it, to examine lymph nodes near the surface of the skin and to help the doctor find the best place to take a biopsy. Cancer Research UK’s page on tests for salivary gland cancer notes that specialists may arrange a neck ultrasound and a fine needle aspiration, and that if the lump is deeper or hard to feel, an ultrasound or CT scan can guide the needle.

Lymphoma Action describes the external scan: you lie on a couch, a cold gel is rubbed over the skin, and a hand-held probe is moved over the area. You might be asked to lie on your side or take a deep breath and hold it for a few seconds to get a better picture. The scan takes about 15 to 30 minutes and is carried out by a doctor, radiographer or sonographer. It is usually done as an outpatient and you can normally go straight home.

Cancer Research UK says that for a neck ultrasound you might feel a little pressure when the sonographer moves the probe over your neck, that it should not hurt, and that the sonographer might ask you to change position a few times to get the clearest pictures. You might have the ultrasound at the same time as a fine needle aspiration, where a fine needle and syringe take a sample of cells from the lump; a local anaesthetic can be given first.

Lymphoma Action says you can take a friend or relative, can ask for a chaperone, and can ask for a sedative if you feel very anxious, in which case you should not drive for the rest of the day. Ultrasound is safe if you are pregnant or breastfeeding.

An ultrasound shows the size, shape and structure of a node and whether there is more than one. What the images mean is a matter for the reporting specialist, who weighs them together with your symptoms, examination and other tests; the sources read for this guide do not give measurements for what counts as abnormal.

Ultrasound is not able to give a definite diagnosis for all nodes. Lymphoma Action notes that it is not possible to tell from X-rays alone whether you have lymphoma and that a biopsy is the standard way of confirming a diagnosis. The same principle applies to ultrasound: the scan guides the next step, which may be reassurance and observation, a repeat scan, a needle sample or a surgical biopsy.

Lymphoma Action says staff in the scanning department will not usually be able to give you the results, because the person doing the scan is not usually trained to interpret the images and an expert uses the scan together with all the other test results. Your medical team should give you an idea of when to expect results, and waiting can be a particularly anxious time.

Possible outcomes include reassurance that the nodes look reactive, with advice to wait and re-check if they have not settled; a needle test of cells; or a biopsy of a node. Lymphoma Action’s page on biopsy, referenced from its scans page, explains that ultrasound can help find the best place to take the sample. Tell your doctor if the lump grows, if you develop night sweats, weight loss or fevers, or if you have difficulty swallowing or breathing; the NHS advises an urgent GP appointment or NHS 111 for very difficult swallowing or breathing with swollen glands.

In the NHS, a lymph node ultrasound is requested by a GP or hospital specialist, and results are reviewed in the context of other tests.

Private ultrasound is available quickly in many areas and can be useful for reassurance, but a private scan should be followed by a clinician who can interpret it, arrange any needle test or biopsy and coordinate with your GP.