Is possible if in msct 64 slice result, the calcium score of lm is 0 ( normal, no stenosis) but in angiografi result have 80% stenosis??

?: What was the calcium score of the entire coronary tree? I doubt it was zero if there's an 80% left main stenosis. That said, not all coronary artery blockage is due to atherosclerosis. You mention AF. It's conceivable that non-calc thrombus from the left atrium could obstruct the coronary tree. Vasculitis & Cor dissection (rare) also can cause non-calc stenosis. (so the answer is "yes").

Quite possible: Not all blockages contain calcium. In general calcium deposits over time so relatively younger plaques may not contain enough calcium to be detected on a CT scan. Also even heavily calcified blockages may not be significant if they don't compromise flow. Need to combine multiple sources, especially stress testing to evaluate the significance of blockages.

Possible.: Calcium score does not have 100% sensitivity for picking up stenosis; thus it is possible to have stenosis with a zero score.

Yes, it: is possible. The calcium scoring CT scan can only identify the burden of calcified atheromatous plaque. It is possible to have non calcified "soft" plaque that won't be detected.