I assume you are referring to a CT scan slice 64 or greater! About 2 years ago, I had a ct scan of the heart that included the lungs and lower descending aorta. The test does an evaluation of the soft plaque between the layers of the major coronary vessels, and depending on degree or score of the amount of soft plaque there is a prediction of how vulnerable an individual is to a heart event and what degreee of CAD advancement if any. My test indicated a high risk for a major heart event within a year. The total score was over 1000.
Cardiac calcium scoring is not done very often because a physical exam and other tests often give enough information about your heart. But if you are at medium risk for CAD based on your risk factors, cardiac calcium scoring may give your doctor more information to decide on your risk of CAD. Medium risk means that you have a 10% to 20% chance of having a heart attack in the next 10 years, based on your risk factors. You can be at medium risk and not have any symptoms of heart disease. No plaque is present. You have less than a 5% chance of having heart disease. Your risk of a heart attack is very low. The scoring table associated with mu CT scan:
1-10 A small amount of plaque is present. You have less than a 10% chance of having heart disease. Your risk of a heart attack is low. But you may want to quit smoking, eat better, and exercise more.
11-100 Plaque is present. You have mild heart disease. Your chance of having a heart attack is moderate. Talk with your doctor about quitting smoking, eating better, beginning an exercise program, and any other treatment you may need.
101-400 A moderate amount of plaque is present. You have heart disease, and plaque may be blocking an artery. Your chance of having a heart attack is moderate to high. Your doctor may want to do more tests and may start treatment for heart disease. Or he or she may start you on aggressive treatment for any risk factors such as high blood pressure and high cholesterol.
Over 400 A large amount of plaque is present. You have more than a 90% chance that plaque is blocking your arteries. Your chance of having a heart attack is high. Your doctor will want to do more tests and will start treatment.
I have a totally blocked LAD (collateral vessels bypass), and circumflex is 72% blocked for more than 6 years.
Hope this helps give you a perspective, and if you have any further questions you are welcome to followup. Thanks for the question.