CTA Coronary (CCTA)

Indications

• Acute/stable chest pain with low-to-intermediate risk; rule out obstructive CAD
• Evaluation of coronary anomalies, bypass graft patency, stent patency (larger stents)
• Pre-procedural planning; CAD-RADS reporting

Patient prep

• NPO 3-4 h (clear liquids OK); avoid caffeine ~12 h
• Heart rate control: oral beta-blocker (e.g., metoprolol 25-100 mg) before arrival and/or IV metoprolol 5 mg increments (or esmolol) to target HR <60-65 bpm
• Sublingual nitroglycerin 0.4-0.8 mg ~1-5 min before acquisition (coronary vasodilation) unless contraindicated (hypotension, recent PDE5 inhibitor, severe AS)
• Screen contraindications to beta-blockers and nitrates; check renal function
• ECG leads placed; 18-20G IV (right antecubital preferred)

Contrast

Technique

• Supine, arms up, ECG-gated; scout + calcium score (optional) first
• Prospective ECG-triggering (axial step-and-shoot) in diastole for regular HR <65 (lowest dose); retrospective gating with dose modulation for higher/irregular HR or functional assessment
• 100 kV for normal-BMI patients, 120 kV for larger; high-output tube
• Coverage carina to below diaphragm (whole heart); single breath-hold (inspiration)
• Recon 0.5-0.75 mm at optimal cardiac phase (~70-75% diastole; systolic ~35-45% at high HR)
• Reconstruct multiple phases as needed

Series / Sequences

Key points

• Heart rate control and regular rhythm are the biggest determinants of image quality; target <60-65 bpm
• Prospective triggering markedly lowers dose vs retrospective gating; reserve retrospective for arrhythmia/functional needs
• Nitroglycerin improves small-vessel visualization; verify no contraindication
• Report with CAD-RADS 2.0; coronary calcium score adds risk stratification
• Beta-blockade contraindicated in severe asthma, decompensated HF, high-grade AV block, severe AS (use caution); use calcium channel blocker alternative

References