Advice after your nerve block for surgery
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Introduction
We have given you this factsheet because you have an appointment for a CT scan. Please make sure you read this information and follow the instructions carefully before your procedure. If you have any further questions, please speak to a member of your healthcare team who will be able to advise you.
The Procedure
Computed Tomography (CT) is an examination using X-rays by lying on a flat table inside a scanner that produces detailed cross sectional images of your body.
These images are cross-sectional (like slices) and are used to produce detailed 2D and 3D images of the organs and other internal structures inside of your body and helps us make a diagnosis or monitor your treatment.
A standard x-ray does not give the same level of detail as a CT scan. During the procedure, contrast media (a special X-ray dye) may be injected into the needle already placed in your arm and this will help to visualise your internal organs and blood vessels.
A cardiac CT (CT coronary angiography) scan is a specialised scan to look at your heart. Just as taking a picture of a moving object with a camera results in a blurry picture, conventional CT scans of the heart are not helpful because the heart is continuously in motion.
A cardiac CT scan obtains the images during the cardiac cycle using the ECG monitoring to get high quality images of:
- coronary arteries – the vessels that bring blood to the heart
- great vessels – the large vessels that bring blood to and from the heart.
Before your appointment
Please let us know if:
- You normally require the Vascular Access Team for injections
- You have limited mobility and will require assistance to get on and off the scanner.
- You will need an interpreter. We are not able to use family members or friends to interpret.
- There is any possibility that you may be pregnant.
- You will be arranging Hospital transport via your GP.
- If you have experienced any previous reaction to contrast injection or you are known to have any kidney problem
- If you have asthma or use any of the following medication
- Verapamil
- Any Beta Blocker.
- GTN spray / tablets
- Viagra (Sildenafil) or similar drugs (phosphodiesterase inhibitors), taken within the last 24 hours.
In order to make your appointment run more smoothly, please let us know if any of these apply, in advance, by calling our bookings team (contact details are displayed on the main Radiology page).
On the day of Examination
Eating – Have a light breakfast on the morning of your examination; you may have fruit juice, milk or water to drink. For afternoon appointments you may also have a light lunch.
Drinking – Do not have tea, coffee (including decaffeinated drinks) or caffeinated /
fizzy drinks from midnight prior to day of your scan, as these contain caffeine which can speed up your heart rate.
Smoking - Please refrain from any Nicotine products (cigarettes, patches, cigar or pipe) from midnight prior to day of your scan.
Medicines – If you are taking any medicines, please continue to take these as usual,
unless you have been told otherwise by your doctor.
On Arrival
Please arrive 15 minutes before your appointment time.
On arrival in the department you should check in at the reception desk. Bring this letter with you and be prepared to confirm your details with the receptionist.
All patients from 12-55 years of age (regardless of gender) who will undergo a Radiology procedure will be asked about the possibility of them being pregnant.
The Examination
- A Radiographer or Health Care Professional will call you from the waiting room for your CT scan. As other patients are having different scans and tests whilst you wait, you may note other patients being called out of order of arrival.
- Your scan may need some preparation beforehand. You may be asked to change into a hospital gown and remove jewellery (this may be best left at home, as the Trust cannot accept responsibility for lost or stolen items).
- We will ask you a series of questions to make sure the scan is safe and can then go ahead.
- A small needle (cannula) will be placed into your arm, in preparation for your scan. ECG monitoring stickers will be attached to your chest.
- When you are ready a Radiographer will call you through into the scan room and ask you to lie down on the CT scanner bed and the scan will occur.
- The CT scanner looks like a large doughnut and the scan bed moves in and out of the middle in order to obtain your scan. The CT scanner is not enclosed, so claustrophobia is not normally an issue. There may be breathing instructions for you to follow; these may require you to hold your breath for up to 10 seconds. If you struggle to hold your breath for this long or find it difficult lying flat on your back, then let the Radiographers know when you arrive.
- The radiographers will be in the CT control room but you will be able to talk to them via an intercom, and they will be watching you all the time.
- If your heart is beating quickly, it can be difficult for us to get a clear picture. If it is faster than the ideal rate, you may be given some medication to slow it down. This is usually in the form of an injection but may also be a tablet. Once your heart rate is slower, we will perform the scan.
- During the scan the contrast dye will be injected via the cannula in the arm. Some patients may experience a general sensation of warmth or a metallic taste in your mouth. Sometimes people have a sensation that they are wetting the bed (but they don't actually do it). These sensations are normal and pass within minutes.
- The scan itself will take approximately 20 minutes.
- Following the scan you will be asked to remain in the department for 10-15 minutes. After this time we will remove the cannula and you can leave the department.
After the Examination
You will be free to resume your normal daily activities.
As you may be given medication which can affect the heart rate please avoid driving after your appointment, as this medication can make you drowsy. The medication can take up to 1 hour to take effect.
The Results
The results of your scan will not be given to you immediately after the scan. The images are interpreted by a Radiologist (doctor specializing in medical imaging) and sent back to your Consultant or GP who referred you for the scan. The result will be sent to your referring Doctor. This can take up to 4 weeks.
Are there any risks?
Occasionally, unpredictable allergic reactions (such as a rash) might occur. These effects are usually mild and of short duration but this is why we ask you to stay in the department for 15-30 minutes after the scan. If, however, they become more severe medical treatment is necessary.
Staff in the Radiology Department are trained to deal with any complications and again the risk involved is very small. It is possible that a reaction can occur up to a week after, if you develop itching or a skin rash you should contact your GP or the A&E Department at the hospital.
If a reaction does occur after you have returned home, please contact the Radiology
department between 9:00am and 4:00pm, Monday to Friday, so that your records can be updated.
There is a small risk that the injection of contrast can leak out into the skin instead of in the vein causing local pain, redness and occasionally tissue damage. If this does happen then advice will be given to by the radiographer and radiologist at the time.
There are some risks involved with CT scans as ionising X-ray radiation is used. Everyone receives ionising radiation every day from radioactivity in the air, food we eat and the sun.
Your age, size and the body part being scanned will influence the amount of medical radiation used and theoretical risks but similar to the natural background radiation we all receive over a period of between 10 months and 7 years.
The benefit of the scan is making the correct diagnosis or treatment plan and a radiology specialist has agreed that this benefit outweighs the risks of radiation exposure. The radiographers are trained to obtain the best possible imaging using the lowest amount of radiation possible and the equipment is regularly checked to ensure it is safe and effective.
Contact us
If you have any queries relating to this information, please contact the Radiology service.
About this information
Service:
Radiology
Reference:
PILS-CT.1
Approval date:
10 February 2025
Review date:
10 February 2028
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Important note
This page provides general information only. It is developed by clinical staff and is reviewed regularly every 3 years for accuracy. For personal advice about your health, or if you have any concerns, please speak to your doctor.