CTCA and ICA characteristics
| Characteristics | Value |
| CTCA | |
| Image quality | |
| Poor | 50 (6.1%) |
| Reasonable | 35 (4.2%) |
| Good | 741 (89.7%) |
| Technique | |
| Flash | 749 |
| Retrospective (spiral CT) | 31 |
| Step-and-shoot | 46 |
| Tube voltage, median | 120 |
| Total DLP (mGy cm), mean, (95% CI) | 249 (219 to 279) |
| Effective dose (mSv), mean, (95% CI)* | 3.49 (3.07 to 3.90) or 6.48 (5.71 to 7.25) |
| Heart rate before scan (bpm), mean, (95% CI) | 61 (61 to 62) |
| Heart rate after scan (bpm), mean, (95 CI) | 57 (57 to 58) |
| Beta-blocker use | 469 (57%) |
| Agatston score | |
| Total score, median, (IQR) | 170 (351) |
| Volume calcium score, median, (IQR) | 180 (310) |
| Calcium mass score, median, (IQR) | 54 (110) |
| ICA | |
| Contrast volume (mL), mean, (95% CI) | 189 (183 to 194) |
| Total DAP (Gyx cm2), mean, (95% CI) | 62.53 (58.39 to 66.67) |
| Effective dose (mSv), mean, (95% CI) | 14.4 (13.4 to 15.3) |
| Clinical management | |
| Conservative | 377 |
| Medical therapy | 189 |
| PCI | 180 |
| CABG | 56 |
| Other | 24 |
Other includes: cardiac valve or structural heart surgery (n=11), additional workup (n=10), referral for electrophysiology (n=2), contra-indication for PCI because of allergy (n=1).
*Effective dose calculated using conversion factor 0.014 mSv/mGy*cm and 0.026 mSv/mGy*cm.
CABG, coronary artery bypass grafting; CTCA, CT coronary angiography; DAP, dose area product; DLP, dose length product; ICA, invasive coronary angiography; PCI, percutaneous coronary intervention.