Diagnostic services
at a glance.

No. Some CT examinations use contrast material and others do not. It depends on the scan requested; ask the centre whether contrast and any preparation apply to your appointment.

Tell the centre or imaging team if you are or may be pregnant, or if you have had a previous reaction to CT contrast or have a relevant allergy. They can review this information for your requested examination.

Preparation varies with the body area and type of scan. Check the instructions for your appointment and ask the centre if you have not received them.

No. Ultrasound creates images using sound waves rather than X-rays. The clinician decides which examination is appropriate for the question being investigated.

The X-ray itself is usually quick and painless. You may need to hold a position briefly so the image can be taken; tell the team if positioning is difficult for you.

Yes. Tell the clinician or radiographer before the examination if you are pregnant or think you may be, so they can consider the right next step for you.

Transient elastography estimates liver stiffness, which can help assess fibrosis. The measurement is one part of a clinical assessment and does not, by itself, identify the cause or give a complete diagnosis.

Preparation instructions can depend on the examination and the centre. Ask whether you should change when you eat or drink before your appointment, and follow the instructions you are given.

Small sensors are placed on the skin to record the heart’s electrical activity. The exact type of ECG and the time needed can vary, so confirm which examination has been requested.

No. An ECG records electrical signals from the heart. An echocardiogram uses ultrasound to create images of the heart.

The Doppler part of an ultrasound can show information about blood flow, including its direction and speed. The area examined depends on the clinician’s request.

Instructions depend on the body area and type of Doppler examination. Ask the centre what preparation applies to your requested scan before travelling.

The breast is positioned and briefly compressed to take the images. Some people find this uncomfortable; tell the imaging team if you feel worried or have found it difficult before.

NHS mammography guidance advises avoiding deodorant, antiperspirant and talcum powder on the day because they can affect the images. Confirm the instructions for your specific appointment with the centre.

An echocardiogram uses ultrasound waves to make images of the heart and help a clinician assess how it is working. It is different from an ECG, which records electrical activity.

Preparation depends on the type of echocardiogram requested. Ask the centre to confirm the exact type and follow the instructions for your appointment.