Coronary artery disease is a leading cause of death in Australia, so finding which patients are at risk of coronary artery disease, is an important consideration. Calcium in the coronary arteries almost always indicates arterial disease or atherosclerotic plaque, but bears relationship to plaque stability or instability. Cardiac risk factors and insulin resistance contribute to coronary artery calcification.
Coronary artery calcium scoring (CACS) is a non-invasive test that estimates the amount of coronary artery plaque, by assessing the extent of coronary artery calcification using high-resolution CT. While a calcium score of ‘zero’ does not rule out arterial disease, there is a low likelihood of significant coronary blockage. A high calcium score correlates with a moderate to high risk of a coronary event, or heart attack, within two to five years.
CACS has a high negative predictive value (up to 98%), which means if your calcium score is low then this correlates very well with you having a low risk of coronary artery disease. Coronary artery calcium scanning is not as useful in patients who have a low or very high risk, or in those with known coronary artery disease.
Possible reasons for requesting CACS include:
Screening asymptomatic patients
Screening patients with intermediate risk of coronary artery disease
Presence of one risk factor such as hypertension
Strong family history of early coronary artery disease
Patients with diabetes or chronic kidney disease could have high calcium scores, which might not correlate with significant coronary artery disease.
At Envision Medical Imaging we routinely use CACS, at no additional charge, on each patient prior to CT coronary angiograms to determine whether the coronary arteries are heavily calcified.
Medicare does not provide patients with a rebate for CACS. Patients having a CACS during a CTCA will not be charged extra. There is no specific patient preparation for CACS.
What happens during a CT Calcium Score?
A. Before your scan
What to bring
Your request form
Any relevant previous imaging
Your Medicare card and any concession cards
Preparation - Day of the scan
You will be asked to fill out a questionnaire regarding your health status, medication, and any known allergies and provide consent for the procedure. If there is any chance you may be pregnant, please inform us before your scan. You may also be asked to change into a gown and remove some jewellery for your scan.
B. During your scan
You will be made comfortable on the CT examination table and our technician will connect you to a ECG (electrocardiogram) heart monitor. Your heart rate will be monitored until it is at rate low enough for the scan to be performed. The examination table slides you into the centre of the CT machine and some preliminary pictures are taken to confirm the scan position.
The technician will ask you to lie still and hold your breath for short periods while each picture is taken. You may hear a humming noise during the scan, but no moving parts will touch you. The scan takes about 10 minutes.
At Envision Medical imaging your CT Calcium Score examination will be carried out by a radiographer (medical imaging technologist), who has a degree in medical imaging and is accredited by the Australian Institute of Radiography. We have a team of Radiologists (a medical doctor specialising in the interpretation of medical images) as well as Cardiologist who will prepare and send a report to your referring doctor detailing the findings of your CT Calcium Score.
What happens after a CT Calcium Score?
What happens after my scan
After your exam you may resume your normal activities.
How do I get my results?
One of our Radiologists or Cardiologist will interpret the CACS and provide a comprehensive report about the findings. Your test result will be reported to your referring doctor or health care provider within 5 working days of the examination. Please ensure that you make a follow up appointment with your referring doctor or health care provider to discuss your CT Calcium Score results.
If the patient needs to be reviewed on the day of the CACS, we will fax or email the results. Processing and reporting of images could take up to two hours. If you are a registered a referrer you can access your patient’s digital x-rays, scans and reports through our secure online archival system, or view the films we provide. For more information about registering to access patient images visit the Access to Online Images Section.