CT Angiography Indications
CT angiography is most appropriately indicated for symptomatic patients with low-to-intermediate pretest probability of coronary artery disease, structural cardiac evaluation (coronary anomalies, congenital heart disease, prosthetic valves), pre-electrophysiology procedure mapping, and acute pulmonary embolism evaluation.
Coronary Artery Disease Assessment
Symptomatic Patients
- Primary indication: Patients with chest pain and low or intermediate pretest probability of obstructive CAD 1
- High-probability CAD patients are generally uncertain indications, except when:
- Patient has interpretable ECG and can exercise
- Definite myocardial infarction is present 1
Asymptomatic Screening
- Inappropriate for routine screening with coronary CT angiography 1
- Calcium scoring (non-contrast CT) is appropriate for:
- Intermediate CHD risk (10-20% 10-year risk)
- Low-risk patients with family history of premature CHD 1
- Avoid repeat calcium testing or repeat CT angiography in stable asymptomatic patients 1
Heart Failure Evaluation
- Appropriate in reduced left ventricular ejection fraction with low or intermediate pretest CAD probability 1
- Uncertain indication for normal ejection fraction 1
Preoperative Assessment
Cardiac Surgery
- Appropriate for non-coronary cardiac surgery (valve replacement, ASD closure) when intermediate pretest CAD risk 1
- Uncertain when low pretest risk 1
Non-cardiac Surgery
- No appropriate indications for coronary CT angiography 1
Post-Revascularization Evaluation
- Left main stents only are appropriate for imaging 1
- Larger stents (≥3mm) after ≥2 years: uncertain indication 1
- Evaluation depends on symptom status, time from revascularization, and stent size 1
Structural and Functional Cardiac Assessment
Appropriate indications include 1:
- Coronary anomalies
- Congenital heart disease
- Right ventricular function evaluation
- Left ventricular ejection fraction when other imaging inadequate
- Prosthetic heart valve evaluation
- Myocardial viability when other modalities inadequate or contraindicated
- Suspected arrhythmogenic right ventricular dysplasia
Procedural Planning
- Appropriate prior to electrophysiological procedures for anatomic mapping 1
- Appropriate prior to repeat sternotomy in reoperative cardiac surgery 1
Non-Cardiac Vascular Indications
Pulmonary Embolism
- Primary modality for acute PE evaluation 2
- Particularly when patient cannot undergo V/Q scanning or has severe renal impairment 2
Aortic Pathology
- Essential for acute aortic syndromes (dissection, penetrating ulcer, intramural hematoma) 3
- High morbidity/mortality conditions requiring rapid diagnosis 3
Peripheral Vascular
- Lower extremity trauma: indicated only when hard or soft signs of vascular injury present 4
- Not indicated for routine evaluation without clinical signs 4
Key Caveats
Common pitfalls to avoid:
- Do not use for asymptomatic screening with coronary CTA 1
- Avoid in high pretest probability CAD where invasive angiography more appropriate 1
- Image quality must be excellent for diagnostic validity; consider alternative testing if good quality not achievable 5
- Recognize that "uncertain" ratings remain reimbursable and clinically reasonable 1