Comparison of CTCA with invasive CAG
| Factor | CTCA | Invasive CAG |
| Invasiveness | Non-invasive | Invasive |
| Cost (£) | 305* | 2000* |
| Radiation dose (mSv) | 2–5 | 2–12 |
| Contrast dose (mL) | 50–120 | 13–90 |
| Spatial resolution (mm) | 0.50 | 0.16 |
| Temporal resolution (ms) | 83–153 | 1–10 |
| Sensitivity for obstructive CAD | High | Gold-standard investigation |
| Specificity for obstructive CAD | Low to moderate | Gold-standard investigation |
| Patient limiting factors | Calcification Tachycardia/irregular heart rhythm Low eGFR | Severe frailty Low eGFR |
| Other limiting factors | Intolerance of rate-limiting medication Motion artefacts | Intolerance of hyperaemia-inducing medication |
| Physiological adjuncts | FFRCT | Invasive FFR/iFR/CFR CAG-FFR |
| Complication rate | Contrast-induced anaphylaxis <1% Contrast-induced nephropathy 3% Side effects related to rate-limiting medications uncommon | Arterial access site complications (radial) 0.2% Major adverse events (MI 0.05%, CVA 0.07%, death 0.08%) Contrast-induced anaphylaxis <1% Contrast-induced nephropathy 3% |
*Average cost of a standard outpatient NHS study.
CAD, coronary artery disease; CAG, coronary angiography; CAG-FFR, angiographically derived fractional flow reserve; CTCA, CT coronary angiography; CVA, cerebrovascular accident; eGFR, estimated glomerular filtration rate; FFR, fractional flow reserve; FFRCT, computed tomography derived fractional flow reserve; iFR, instantaneous wave-free ratio; MI, myocardial infarction.