RadteraCoronary Artery Calcium Score (CAC)
CTNo contrastCardiac
Indications
- Cardiovascular risk stratification in asymptomatic intermediate-risk adults (ASCVD risk refinement)
- Guiding statin/aspirin decisions
- Baseline before CCTA
Patient prep
- No contrast, no beta-blocker required (HR control optional but improves quality)
- ECG leads placed; remove metal from chest field
- No NPO requirement
Contrast
None / non-contrast
Technique
- Supine, arms up, prospective ECG-triggering at ~70-80% R-R (diastole)
- Coverage carina to diaphragm (heart); single breath-hold
- Fixed 120 kV (standard for Agatston calibration), low mAs
- Reconstruct 2.5-3 mm contiguous axial, standard (non-sharp) kernel, no overlap as required by scoring software
- Score with Agatston method on dedicated software
Series / Sequences
| # | Series / Sequence | Plane | Thickness | Notes |
|---|---|---|---|---|
| 1 | Axial non-contrast gated | axial | 2.5-3 mm | 120 kV, standard kernel; input for Agatston scoring |
Key points
- Use fixed 120 kV and standardized 2.5-3 mm slices so Agatston scores are comparable/reproducible
- Report total Agatston score with age/sex percentile; Agatston 0 = very low risk
- Very low dose exam (~1 mSv)
- Motion from high HR can create blooming/artifactual scoring; gating mitigates
- Incidental non-cardiac findings (lung nodules) should be noted
References
• Hecht HS, Cronin P, Blaha MJ, et al. 2016 SCCT/STR guidelines for coronary artery calcium scoring of noncontrast noncardiac chest CT scans: A report of the Society of Cardiovascular Computed Tomography and Society of Thoracic Radiology. J Cardiovasc Comput Tomogr. 2017;11(1):74-84. link
• Grundy SM, et al. 2018 AHA/ACC/Multisociety Guideline on the Management of Blood Cholesterol. Circulation. 2019;139(25):e1082-e1143; and Arnett DK, et al. 2019 ACC/AHA Guideline on the Primary Prevention of Cardiovascular Disease. Circulation. 2019;140(11):e596-e646. link
• Radiopaedia: Agatston score link
• Grundy SM, et al. 2018 AHA/ACC/Multisociety Guideline on the Management of Blood Cholesterol. Circulation. 2019;139(25):e1082-e1143; and Arnett DK, et al. 2019 ACC/AHA Guideline on the Primary Prevention of Cardiovascular Disease. Circulation. 2019;140(11):e596-e646. link
• Radiopaedia: Agatston score link
Source: Researched — verify against your institution
Reference template — verify and adapt to your scanner, vendor and institution before clinical use. Not a substitute for clinical judgment.