North Shore Radiology uses the latest CANON Aquilion One prism CT scanner, providing superior image quality. This CT can scan the entire heart in one heartbeat, which means ultra-low doses of radiation are required to get a clear image. The speed and design also dramatically improves patient comfort while scanning.
We ask you to have someone accompany you and drive you to and from the examination, which will help you arrive in a rested state.
As the heart moves, we need to collect data during the quiet time of heart activity, called diastole (when the heart is not pumping), as this provides the best images. We want your heart rate (pulse) to be slow; therefore, we ask that you not consume any chocolate or drinks with caffeine (tea, coffee, fizzy drinks/coke etc.) for 12 hours before the test.
You must also fast for two hours before your scan and ensure you are well hydrated with water.
We may arrange for you to take a drug called a β blocker the night before and the morning of the test or after you arrive for your appointment. This helps in slowing down your heart rate and enables a quality scan.
Please bring any previous relevant imaging, particularly CTs. Details of your cardiac medications and previous heart surgery (such as by-passes) will be required.
Continue to take all usual medication.
The time for this examination varies depending on your heart rate, but most scans take 30 minutes. If your heart rate is too fast, we may have to prepare you more before the scan, which can delay the time until we can do the scan. Please allow yourself plenty of time.
Upon arrival, you will be taken to the nurses’ trolley bay. You will have your blood pressure and heart rate measured. If your heart rate is too fast, you may be given additional medication to slow it down. You will be asked to fill out a questionnaire to make sure you are not allergic to the Intravenous Contrast (X-ray dye), which we use for the CT and to check you have no other problems.
You will also be asked to sign a consent for the administration of the X-ray contrast. After entering the CT room, you will be positioned on the padded scanner table. This table will move you so that your heart is in the middle of the scanner. The radiographer controls the examination from a separate room next to the scanner. You will be able to talk to the radiographer at all times.
A needle will be placed in a vein, usually in the right arm, to give the contrast (X-ray dye). A spray of glyceryl tri-nitrate will be given under your tongue to help dilate the coronary vessels and highlight these vessels for us to see.
It is important to let the staff know if you are taking:
prior to the glyceryl tri-nitrate as it cannot safely be given with these drugs. Sometimes the spray may give you a short-term headache.
Each scan will take only a few seconds to complete. You will be asked to hold your breath for the scans. It is important to obey any instructions given. During the scan, you will hear the sound of the machine moving around you.
The intravenous contrast (X-Ray dye) shows the arteries during the injection. You may feel slightly warm or have a flushing sensation or have a metallic taste in your mouth. Some patients even briefly feel as though they have urinated. These sensations are normal and are no cause for concern.
Reactions to the dye are rare, but our staff are fully trained to provide the necessary treatment if such a reaction occurs.
Our nursing staff or radiographers will remove the cannula in your arm, and you will be able to change into your clothes. You should feel no after effects, and no further care is required after your examination has finished.
You may resume your regular diet immediately, as well as your everyday activities, although we ask that you avoid rigorous exercise for 24 hours following the test. Please ensure you have someone to drive you home following the procedure.
The intravenous contrast injection (X-Ray dye) you received will be excreted through your urine over the next 24-48 hours following your test. We suggest you increase your water intake over this period to assist the excretion of dye from your kidneys.
The radiologist and cardiologist will study your films and prepare a written report. Please allow two working days for these results to be available.
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