Advice after your nerve block for surgery
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Introduction
We have given you this factsheet because you have an appointment for an MRI scan looking at the heart. 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
Magnetic Resonance Imaging (MRI) is an examination using strong magnetic field and radio waves by lying on a flat table inside a scanner (a large, hollow tube open at both ends) 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. Unlike X-rays and CT (computed tomography) scans, MRI scans do not use radiation. It is a safe, painless technique with no known risks, provided the safety questionnaire is correctly completed.
A stress Cardiac MRI scan is a scan of your heart during which you will be given a drug called adenosine. This mimics the effect of performing exercise on your heart whilst you are lying down in the scanner.
Before your appointment
Due to the strong magnetic field used by the scanner, people with certain types of medical implants or devices may not be able to be scanned. Some examples: people fitted with a pacemaker, some types of head surgery, certain metal implants or if there has ever been any injury to the eyes involving metal fragments.
Please review the MRI safety questionnaire enclosed in this letter and fill this in before your appointment. This can be completed on paper and should be brought to the appointment.
Where indicated this can also be completed online.
If you answer yes to any of the questions, please call the department.
Due to the drugs used please call us to let us know if you have any of the following:
- Asthma or if you require any inhalers
- If you have problems with your kidney function
- If you are currently taking Persantine/dipyridamole or theophylline
Please bring a list of your current medications with you.
Please also 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. 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.
- requiring Hospital transport via your GP
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).
Eating and Drinking
For the 12 hours before your scan appointment it is essential that you do not have any caffeinated drinks, food or medication. This includes:
- Caffeine–containing painkillers or cold medication
- Chocolate
- Energy Drinks or Fizzy drinks
- Hot chocolate
- Ovaltine or Horlicks
- Tea/coffee (including de-caffeinated)
You may otherwise eat a normal diet and drink water, squash, milk and fruit juices.
On Arrival
Please arrive 20 minutes before your scan 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.
What to wear
You will not be able to wear anything inside the scanner room that contains any metal. This includes zips, metal buttons, poppers or metallic print. Please wear suitable clothes to your appointment or bring them with you to change into. If required, we will provide you a hospital gown. Some makeup products also contain metal particles and should be avoided.
The procedure
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A Radiographer or Health Care Professional will call you from the waiting room for your MRI 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.
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You may be asked to change into a hospital gown or your own clothing without metal components. We will provide a locker in which you can store your metal items, watches, credit cards etc. But these may be best left at home, as the Trust cannot accept responsibility for any lost or stolen items.
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We will ask you a series of questions to make sure the scan is safe and can then go ahead.
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A small needle (cannula) will be placed into your arm, in preparation for your scan.
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When you are ready a Radiographer will call you through into the scan room and ask you to lie down on the MRI scanner table and attach ECG leads to your chest and a blood pressure cuff will also be used on one of your arms to monitor your blood pressure and your heat rate during the scan. We will use pads, cushions and supports to help make you more comfortable for the scan. It is important to be as comfortable as possible from the beginning to help you keep still throughout. A ‘receiving device’ like an aerial, may be placed behind or around the part of the body being examined. This detects the tiny radio signals emitted from the body during the scan.
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The MRI scanner will make very loud and unusual noises whilst taking your pictures.
Earphones and/or earplugs will be given. -
For the first 15 minutes scans of your heart will be taken. You will then receive the injection of Adenosine into the vein for about 3 minutes. This will makes your heart work harder (beat faster) as if you were exercising. Initially you may not notice anything. After a minute you may start to feel a little breathless and get a tight chest and feel flushed. After 3 minutes, more scans will be taken and you will receive a contrast injection to show the blood supply to the heart. This scan takes about 1 minute and during this time the adenosine injection is turned off and any symptoms you had will disappear within seconds. After this part of the scan is completed there will be a further 20 minutes of scanning.
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The radiographers will be in the MRI control room but you will be able to talk to them via an intercom, and they will be watching and monitoring you all the time. You will also be given a buzzer to press if you need to attract our attention during your scan.
After the Examination
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. You will be free to resume your normal daily activities
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 following the contrast dye injection. 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 an 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 let the radiology department know so that your records can be updated.
Contact us
If you have any queries relating to this information, please contact the Radiology service.
About this information
Service:
Radiology
Reference:
PILS-MRI.1
Approval date:
3 October 2024
Review date:
3 October 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.