Found this on one site. I think it gives you a good idea of what to expect.

CAC = 0
No identifiable atherosclerotic plaque.
Low risk for cardiovascular disease.
Less than a 5% chance of coronary artery disease.

CAC = 1-10
Minimal plaque burden.
Significant coronary artery disease is unlikely.

CAC =11-100
Mild plaque burden.
Likely mild or minimal coronary stenosis.

CAC = 101-400
Moderate plaque burden.
Moderate non-obstructive coronary artery disease is highly likely.

CAC = Over 400
Extensive plaque burden.
High likelihood of at least one significant coronary stenosis (>50% diameter).