Advice after your nerve block for surgery
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Heart blood vessels and narrowing
The coronary arteries supply the heart muscle with oxygen carried in the blood. In some people these arteries become narrowed and the flow of blood to the heart muscle is reduced.
Your consultant or cardiac specialist nurse has requested this examination to find out whether this is causing your symptoms.
Who do I contact if I want to change my appointment?
Please ring 0300 613 4140 option 2 for CT appointments
What preparation should I make and what should I bring?
If you are on a medication called metformin for diabetes, please do not take this on the day of the procedure.
Please tell us if you have
• Diabetes
• Asthma
• Kidney disease
• Heart disease
• Thyroid problems
• Any allergies
• or if there is any possibility you may be pregnant
and please bring
• A list of all your medications
Metal objects including jewellery, eyeglasses, dentures and hairpins may affect the CT images. Please leave them at home if possible; or remove them before your examination
Where do I go?
Please enter Frimley Park Hospital via the main entrance and walk straight through onto the main corridor and then turn left on yellow street (by the lifts). Walk along the corridor until the corridor branches off and bear left. Continue walking towards the lifts and the CT department is on your right. Please book in with the receptionist on arrival.
What happens on the day?
When you arrive, one of the nurses will call you through and ask you to get changed into a hospital gown; you only need to remove the top half of your clothing.
The nurse will then check your blood pressure and pulse and go through a safety questionnaire with you before the scan. The nurse will also insert a cannula into a vein on the back of your
hand before the scan; this is where a special dye called a contrast is injected in the second part of the scan to help improve the quality of the images.
During the CT scan you will need to lie on your back on a flatbed that passes into the CT scanner. The radiographer will operate the scanner from the next room. While the scan is taking place you'll
be able to hear and speak to them through an intercom. While each scan is taken you will need to lie very still and breathe normally. This ensures that the scan images aren't blurred. You may be asked to breathe in, breathe out, or hold your breath at certain points.
You may also need another medication that is in the form of a spray or tablet under the tongue just before the scan. This medication opens up the arteries in the heart making it easier to see and
assess them during the scan. Some people experience a slight headache or some dizziness after taking this.
You will be given an injection of x-ray contrast (sometimes called dye) so that we can see your heart and arteries clearly. The dye (which contains iodine) is usually safe and adverse reactions are rare, although it is common to get a ‘hotflush’, a metal taste in your mouth and/or a feeling that you have ‘wet the bed’ (please be assured you will not do so). These sensations are perfectly normal and pass within a couple of minutes.
How long does the procedure take?
The scan will usually take around 20-30 minutes.
What are the risks or complications of the procedure?
CT scans are quick, painless and generally safe. However, there's a small risk you could have an allergic reaction to the contrast dye and you will be exposed to X-ray radiation.
Severe reactions, including persistent vomiting, urticarial rash (commonly known as hives), face and mouth swelling and very severe reactions, including anaphylaxis, are extremely rare and only occur in 0.004% (four in one hundred thousand) of cases.
CT scanners are designed to make sure you're not exposed to unnecessarily high levels. Generally, the amount of radiation you're exposed to during each scan is the equivalent to between a
few months and a few years of exposure to natural radiation from the environment. It's thought exposure to radiation during CT scans could slightly increase your chances of developing cancer
many years later, although this risk is thought to be very small (less than 1 in 2,000).
Very occasionally, the contrast can leak outside the vein which causes temporary swelling and discomfort in your arm. If this does happen we will provide you with further instructions and
advice to follow.
For more information, read
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Is it claustrophobic?
Unlike a similar test you may have had or heard about, an MRI scan, most patients do not find the CT scanner claustrophobic.
What happens afterwards?
After your CT scan is completed, you may resume all of your normal activities; there should be no side effects.
If you are given medication in the scanner to bring your heart rate down you will need to stay for around 20 minutes after your scan.
We recommend that you drink plenty of water after your scan is complete; this is so that the contrast dye can be quickly flushed from your body and you do not become dehydrated.
When will the results be ready?
All results will be sent to the clinician/specialist nurse who referred you for the scan. They will be in contact with you if you require any further investigations. Your GP will also be sent a copy of your CT report.
Contact us
If you have any queries relating to this information, please contact the Cardiology service.
About this information
Service:
Cardiology
Reference:
C/013
Approval date:
8 July 2024
Review date:
1 July 2027
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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.