Ultrasound scan for ovarian cancer

You might have an external ultrasound of your lower tummy (pelvis) or a vaginal ultrasound to help diagnose ovarian cancer. 

Ultrasound scans use high frequency sound waves to create a picture of a part of the body. It can show the ovaries, womb and surrounding structures.

During an external ultrasound of your pelvis, the doctor or radiographer moves a probe over the lower part of your tummy. For a vaginal ultrasound, they insert the probe into your vagina. This is called a transvaginal ultrasound.

Why you have it

Pelvic ultrasound and vaginal ultrasound scans can show whether:

  • your ovaries are the right size
  • your ovaries look normal in texture
  • there are any cysts in your ovaries

Vaginal ultrasound can help to show whether any cysts on your ovaries contain cancer or not. If a cyst has any solid areas it is more likely to be cancer.

Sometimes, in women who are past their menopause, the ovaries do not show up on an ultrasound. This means that the ovaries are small and not likely to be cancerous.

If you have a suspicious looking cyst, your specialist will recommend that you have surgery to remove it. The cyst will be looked at closely in the laboratory.

Risk of malignancy index (RMI)

Doctors can use a tool called the risk of malignancy index (RMI) to decide if an abnormality is more likely to be cancer or not. This index combines the results of the ultrasound, CA125 blood levels and menopausal status (whether or not you are past the menopause).

This gives doctors a final score. Women with a high score are referred to a specialist multidisciplinary team (MDT). They decide on which further tests and surgery may be necessary.

Your specialist may ask you to have a CT scan to show the ovaries more clearly. Sometimes though, it is not possible to diagnose ovarian cancer for certain without an operation.

If your specialist thinks it unlikely that you have cancer, but cannot completely rule it out, they may ask you to come back for a repeat ultrasound scan in 3 months time, to see if anything has changed.

External ultrasound scans

Preparing for your scan

Check your appointment letter for any instructions about how to prepare for your scan.

You might need to stop eating for 6 hours beforehand. Let the scan team know if this will be a problem for any reason, for example if you are diabetic.

They might ask you to drink plenty before your scan so that you have a comfortably full bladder.

Take your medicines as normal unless your doctor tells you otherwise.

Before the scan

When you arrive at the clinic a member of staff might ask you to take off your clothing down to your underwear and put on a hospital gown. It will depend on what part of the body you're having scanned as to whether you have to undress or not. 

During the scan

You lie on the couch next to the ultrasound machine. You might be able to sit up depending on which part of your body is being scanned.

The sonographer will spread a clear gel onto your skin over the area they are checking. The gel feels cold. It helps to transmit the sound waves to the microphone. The scan appears on a screen next to you. 

You might feel a little pressure as the sonographer presses the microphone against your skin and moves it around the area being scanned. Tell them if this is uncomfortable. 

An ultrasound scan can take up to 45 minutes depending on what's being scanned.

Diagram showing an ultrasound scan

Vaginal ultrasound

You might have a vaginal ultrasound to look at the ovaries, womb and surrounding structures. It is called transvaginal ultrasound or TVS.

Preparation for the scan

There is no special preparation needed for this scan. So you can eat and drink normally. And you can take your medications as normal.

The doctor or sonographer will ask you to empty your bladder before you have the scan. They may ask you to change into a hospital gown or undress from the waist down. You will have a sheet to cover you.

Before the scan

The doctor or sonographer asks you to lie on your back with your bottom at the end of a short scanning couch. There are supports for your feet so you can bend your knees and have your legs apart. If this position is difficult for you, you may be able to lie on your side with your knees drawn up to your chest.   

During the scan

The doctor puts a small thin ultrasound microphone or probe into your vagina. This looks like the same shape and size as a tampon. The probe is covered with a protective sheath like a condom and has some lubricating gel on it. The test may be uncomfortable and a little cool from the gel, but shouldn't hurt. This type of scan does not take long.

The sonographer will gently move the microphone or probe to get the pictures they need. At times the sonographer may place their hand on your tummy and press to move some of your organs to get a clear view on the screen.

What happens afterwards

You can eat and drink normally after the test. You can go straight home or back to work afterwards.

Possible risks

An ultrasound scan is a very safe procedure. It doesn’t involve radiation and there are usually no side effects.

Getting your results

You should get your results within 1 or 2 weeks. The doctor may be able to let you know if they have seen any abnormal areas that have been sent to the laboratory.

Waiting for results can make you anxious. Ask your doctor or nurse how long it will take to get them.

Contact the doctor who arranged the test if you haven’t heard anything after a couple of weeks.

You might have contact details for a specialist nurse and you can contact them for information if you need to. It can help to talk to a close friend or relative about how you feel.

For information and support, you can also call the Cancer Research UK nurses on freephone 0808 800 4040. The lines are open from 9am to 5pm, Monday to Friday.
Last reviewed: 
04 Jan 2022
Next review due: 
04 Jan 2025
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    National Institute for Health and Care Excellence (NICE), April 2011

  • Newly diagnosed and relapsed epithelial ovarian carcinoma: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up

    J Ledermann and others; ESMO Guidelines Working Group

    Annals of Oncology. 2013 Oct;24 Suppl 6:vi24-32.

  • The Royal Marsden Manual of Clinical Nursing Procedures, 9th edition
    L Dougherty and S Lister (Editors)
    Wiley-Blackwell, 2015

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