CT Calcium Scoring
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 64-slice 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 Lake Imaging we routinely use CACS, at no additional charge, on each patient prior to CT coronary angiography to determine whether the coronary arteries are heavily calcified. If the calcium score is high, calcium might obscure the coronary arteries. The radiologist will review the CACS before staring CT coronary angiography.
Before coronary artery calcium scoring
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.
During coronary artery calcium scoring
No x-ray contrast in injected during this test.
Our staff will ensure that all patients receive minimal radiation dose during an examination. The dose for CACS varies depending on factors such as patient size and body shape, but is relatively low.
After coronary artery calcium scoring
While the scan is completed in less than one minute, patients need to remain lying for around 15-20, with an overall appointment time of 30 minutes. Complex data sets are processed into 3D images after the scan, which is time consuming. Generally results will not be available immediately.
One of our radiologists will interpret the CACS and provide a comprehensive report about the findings. We will advise the patient to return to the referrer to discuss CACS 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.
If the patient needs to be reviewed on the day of the CACS, the patient can wait for the CD and we will fax or email the results.