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Ultrasound scan of the urinary tract

Patient information A-Z

This leaflet provides information for patients having an ultrasound scan the urinary tract (kidneys and bladder).

What is an ultrasound scan?

An ultrasound scan uses high frequency sound waves (above the audible range) to acquire images of structures within the body.

To perform the ultrasound scan we put ultrasound gel over the area to be scanned and a small plastic probe (transducer) is slowly moved over the area of interest. This probe transmits high frequency sound waves into your body. Based on the reflections of these sound waves, the ultrasound machine then creates images of your organs. Ultrasound imaging is considered to be very safe as it does not use any radiation to acquire the image.

The scan may identify the cause of your symptoms or help to rule out conditions that could cause your symptoms.

Ultrasound scans are performed by sonographers and radiologists (practitioners). Both female and male practitioners undertake these scans and act as chaperones.

Before your ultrasound scan

We ask that you attend for your scan with a full bladder and recommend that you drink at least one litre of non-fizzy drink in the two hours before your scan. This helps us to see the bladder more clearly on the scan.

During your ultrasound scan

The light will be dimmed in the room so that the practitioner can see the screen better. You will be asked to lie down on the couch and move your clothes to expose your abdomen (tummy). Gel is then applied to your skin; this may feel cold. The transducer is then moved on the surface of the skin over the area of interest. To improve image quality, you may be asked to change position on the couch or to hold your breath. Halfway through the scan, we may ask you to empty your bladder, and we will then measure the bladder again to see if it fully empties. The scan usually takes around 10 to 15 minutes. During this time, the practitioner will take routine pictures and measurements.

You may be asked some questions relating to your symptoms, and also of your previous medical history. At the end of the scan, you will be given paper towels to wipe off the gel before you dress.

After your scan

After your scan, you can return to your normal daily activities.

The practitioner may be able to provide information about the findings; however, results will be sent back to the clinician who referred you for the scan in approximately seven to ten days.


Ultrasound scans do not use radiation and are considered to be a safe non-invasive procedure which can provide clinicians with information to aid diagnosis of a wide range of conditions.


‘’Ultrasound is now accepted as being of considerable diagnostic value. There is no evidence that diagnostic ultrasound has produced any harm to patients in the time that it has been in regular clinical practice” (British Medical Ultrasound Society 2021).

There is a very low risk of infection from the use of ultrasound gel. This can be reduced by wiping the gel off thoroughly at the end of the scan and washing it off as soon as is practical.

Alternative types of imaging available

Ultrasound is the recommended first line investigation for symptoms affecting the urinary tract.

Contacts/ further information

Ultrasound Department: 01223 216455

References/ sources of evidence

We are smoke-free

Smoking is not allowed anywhere on the hospital campus. For advice and support in quitting, contact your GP or the free NHS stop smoking helpline on 0800 169 0 169.

Other formats

Help accessing this information in other formats is available. To find out more about the services we provide, please visit our patient information help page (see link below) or telephone 01223 256998.

Contact us

Cambridge University Hospitals
NHS Foundation Trust
Hills Road, Cambridge

Telephone +44 (0)1223 245151