Computerised Tomography

Computed Tomography (CT) is a scan process that involves using x-rays and a computer to produce detailed 3D images of the area being examined.

Countess of Chester Hospital – CT Department

  • We have three CT scanners at the Countess of Chester Hospital.
  • The CT department works closely with numerous multi-disciplinary teams such as Stroke, A+E and Cardiology.
  • We have a well-established CT Cardiac service.
  • CT is available 24 hours a day, seven days a week for emergencies.

Please note: all outpatient CT scans are by appointment only. These are available Monday to Friday – 08:00 and 20:30

Ellesmere Port - CT Department

  • At our Community Diagnostic Centre at Ellesmere Port Hospital we have one Canon CT scanner.
  • Ellesmere Port Hospital offers free parking.

Please note: all outpatient CT scans are by appointment only. These are available Monday to Friday – 08:30 and 17:00

If your doctor has referred you for a CT scan. : This page contains information for patients, parents and carers about having a CT scan, how to prepare and what happens during your scan.

What is a CT scan?

A CT scan is a type of examination where x-rays are used in combination with computer technology to create a detailed 3D image of the body.

The scanner is a slim, doughnut-shaped machine with a table which moves through the hole in the middle whilst you are being scanned.

How to prepare for your scan

Please read all the information sent to you regarding your appointment. It is important as it might mean we can’t complete your scan.

You will receive instructions on your appointment letter of the preparation needed prior to your CT scan. Some scans require you not to eat for four hours before the examination.

 If you are having an injection of contrast (dye) you will be asked to follow a hydration protocol. This involves drinking two litres of fluid per day for one day before and one day after your CT scan.

This may seem a lot to drink but it is to help hydrate your kidneys prior to and after the contrast (dye) injection. If you have any issues with drinking this much fluid, please contact the CT department for advice. Please continue to take all medications as normal.

Giving your consent

We want to involve you in all decisions about your care and treatment.

The radiographer will check your details with you, they will also confirm which part of your body you are expecting to have scanned and if you are happy for the scan to go ahead. This is called verbal consent and confirms that you have agreed to the procedure and understand what it involves.

The doctor that refers you for the scan will explain the risks and benefits of the test. If you are unsure about any aspect of the scan please do not hesitate to speak to the doctor or the radiographer carrying out the scan.

What happens during the scan?

On arrival at the CT department, you may be asked to change into a hospital gown.

You will be taken into the CT room where your details will be checked. The examination will be explained to you and you can ask any questions.

You will then be asked to lie on the scanner table – some scans you will lie headfirst and others you will be feet first, depending on the part of the body to be scanned. The radiographer can see and hear you at all times and the scan takes about 10 minutes.

For some scans you may also be required to hold your breath for short periods of time –you will hear these instructions when it is needed.

Will you need an injection?

For some scans it may be necessary to give you an injection of contrast dye. The injection will be given into a vein in the back of your hand or arm and you may experience bruising at the injection site.

What is the contrast dye?

The contrast dye is a colourless liquid which is iodine-based. This is a routine part of CT examinations.

The contrast dye is used to highlight the blood vessels in your body and gives more information for the radiologist to aid reporting your scan. The contrast dye is excreted by the body through the kidneys. You may be required to have a blood test prior to your CT appointment to check your kidney function. If required, information will be attached to your appointment letter.

Are there any side effects of the injection?

When the contrast dye is injected, you might feel a hot flush and get a metallic taste in your mouth. Some patients can experience a sensation of passing urine, but they don’t actually do it. These sensations are normal and pass within a few moments.

It is rare to react to the contrast dye. The most common allergic reactions are nausea and vomiting, headache, sneezing, itching, flushing, mild skin rash or hives. These are usually soon after the injection. Please inform the radiographer if you experience any of these symptoms.

Sometimes the reaction can be serious (risk: 1 in 2,500) or even life threatening (risk: 1 in 25,000). Please let the radiographer know if you have had any reaction to x-ray dyes in the past.

If you experience any of these symptoms after you have left the department please contact your local A&E department.

After the CT scan?

If you have had an injection of contrast you will need to wait in the CT waiting room for 20 minutes after your injection. Then you are free to go. You may eat and drink normally following your scan.

You will not receive any results on the day. The images will be reviewed by a radiologist and a report sent to the doctor that referred you for the scan. An explanation of how to get your results will be given to you after the examination.

Special information for persons of childbearing age (12 – 55 years)

If you have reason to believe that you may be pregnant, please contact the CT department on the number on your appointment letter before starting any preparation and before attending your appointment. As the examination uses x-rays there is a risk to any unborn child, especially in early pregnancy.


Current guidelines state that it is safe to breastfeed following injection of contrast dye as so little is passed to the baby via the breastmilk; however, we advise further discussion with the radiographer to make an informed decision.

Alternatively, if you prefer you can express and discard breastmilk for 24 hours following the scan when the contrast will have been excreted.


We are unable to offer childcare facilities and your children cannot go in the scan room with you. If you need to bring your children with you, please bring along somebody who can look after them while you are being scanned.

CT scan patient information leaflets

Information About Your Cardiac CT Scan

Information About Your CT Scan (non contrast scan)

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