- Uses non-contrast CT with a fixed threshold of 130 Hounsfield units (HUs) for calcium detection
- With modern scanners and protocols, the radiation dose required for acquisition of a CT calcium score is approximately 1 mSV.
- Weighting
- A weight of 1 is given for attenuation of 130 to 199
- 2 for 200 to 299
- 3 for 300 to 399
- 4 for attenuation ≥400
- The weighting factor is multiplied by the area of each lesion, with the sum of values for all lesions used to determine the total Agatston score
Power of Zero (CAC of 0)
- What does a zero coronary artery calcium score tell us?
- Intermediate Risk w/ dyspnea or classic angina
- 16% incidence inducible ischemia on PET
- High Risk Symptomatic Patients in ED w/ ACS
- 70% prevalence of obstructive CAD by CCTA
- 🌟 Negative CAC is helpful in Low and Intermediate Risk population (but not high-risk populations)