CT scan (Computerised tomography)

A CT scan uses X-rays from many different angles to give a detailed view of body structures. It is a painless procedure and lasts from 10 to 20 minutes, depending on the type of CT scan you are having. You will lie on an X-ray table which will move inside the doughnut-shaped CT scanner during the examination.

What is a CT scan?

CT scan images provide much more detailed information than plain X-rays do. The CT scan delivers a detailed series of X-ray images of the body and uses computer processing to produce cross-sectional images (slice images), of the bones, blood vessels and soft tissues. Almost all parts of the body can be visualized on a CT scan.

A CT scan has many uses.

• It is very useful for providing a quick examination of patients who may have internal injuries from car accidents or other trauma. 
• It is used to diagnose disease, injury or to plan medical, surgical or radiation treatment. 
• It is also used to monitor diseases and conditions such as cancer, heart disease, lung nodules, liver masses and the effectiveness of certain treatments e.g. cancer treatment.

Preparing for your CT scan

Below are some information leaflets to help you prepare for your CT scan. Preparation requirements vary from one type of scan to another so please ensure you follow the instructions for the particular type of CT scan you are having.

This information will be contained in your appointment letter. Some medications may need to be altered around the time of the scan. If you are unsure, please contact us for advice.

• Preparing for your CT colonography 
• Preparing for your CT coronary angiography 
• Preparing for your CT nerve root block injection 
• Preparing for your CT thorax, abdomen and pelvis 
• Preparing for your CT thorax, abdomen and pelvis with IV contrast 
• Preparing for your CT thorax, abdomen and pelvis with oral contrast 
• CT pre hydration information 
• CT scan blood test information 

What happens during a CT scan?

At the beginning of the scan, the radiographer will ask you to lie on either on your back or front on a padded examination table. The table will then move into position for the scan and during the examination it will move slowly through the CT scanner. The scanner is not enclosed. 

You must lie very still while each picture is taken, to avoid blurring the images. You may also be asked to hold your breath for a moment during the scan. You should not feel any pain during the CT scan.

Certain types of CT exams require an injection of X-ray dye or contrast agent. If you require this a small cannula will be inserted into your arm before the CT scan.  If you are attending a renal (kidney) consultant or have had any kidney procedures performed in the past e.g. nephrectomy (kidney removal), you must make an appointment at the Mater Hospital or your own GP to have a blood test a few days prior to your CT appointment. You must bring these results with you on the day of your appointment. If you have any queries please contact your consultant within the hospital.

If we are scanning your abdomen, you may need to have a drink which has contrast dye in it. Try to avoid passing urine until your scan is over.

What happens after a CT scan?

In most cases, you will be able to leave the Radiology Department immediately. You can return to normal activities.

If you have had a contrast injection, you may need to wait a few minutes in the department before you can leave.

Images are then studied by a radiologist (doctor who uses x-rays to diagnose and treat illnesses) and the results will be sent to the doctor who referred you. 

You may already have an appointment with the doctor who referred you. If not, you may need to contact them to discuss the results and any potential treatment you may need.

If you are a hospital inpatient, the results will be available to the doctors looking after you on the ward.

Do I need to bring anything?

We recommend that you wear comfortable clothing that can be easily changed if required. Avoid wearing jewellery as we may need to remove it depending on the type of X-ray you are having. 

Getting results

Results will be sent to the doctor that referred you for the scan.
Outpatients will receive results at their next outpatient appointment.
Inpatients will receive their result from their in-house doctor.