RadteraCTA Pulmonary Veins / Left Atrium (Pre-Ablation)
CTA+ ContrastCardiac
Indications
- Pulmonary vein and left atrial mapping before atrial fibrillation ablation
- Integration with electroanatomic mapping systems
- Post-ablation pulmonary vein stenosis assessment
- Left atrial appendage evaluation (thrombus, pre-occlusion device sizing)
Patient prep
- ECG leads on (gated acquisition); shave/prep skin as needed for a clean trace
- Coach breath-hold; rate control helpful but less critical than coronary CTA
- 18 G IV preferred for high flow
- Screen eGFR/contrast allergy
Contrast
Agentiodinated (e.g. iohexol 350 or iopamidol 370)
RouteIV
Dose≈80-120 mL; multiphasic injection works well (e.g. ~90 mL at 5 mL/s, then ~30 mL at 3 mL/s, then saline at 3 mL/s) to keep the left atrium dense while clearing the SVC
TimingBolus tracking with ROI in the ascending aorta (above the pulmonary artery), trigger ~100 HU
Technique
- ECG-gated helical/volume acquisition; coverage from above the aortic arch through below the heart base (entire LA and all pulmonary veins)
- Prospective gating for lower dose; retrospective/multiphase if ventricular function (EF) is also requested
- Thin 0.5-1 mm isotropic recon; 3D endocardial segmentation of LA + PVs exported to the EP mapping system
- Measure PV ostial diameters/areas; document PV anatomic variants
- If LAA thrombus is the question: add a delayed acquisition (~30-60 s) — true thrombus persists, slow-flow stasis fills in
Series / Sequences
| # | Series / Sequence | Plane | Thickness | Notes |
|---|---|---|---|---|
| 1 | Gated arterial axial source | axial | 0.5-1 mm | LA/PV anatomy, dense LA opacification |
| 2 | 3D LA/PV segmentation | 3D | VR | Export for electroanatomic map integration |
| 3 | PV ostial measurements | oblique | thin | Per-vein ostial diameter/area, baseline for stenosis follow-up |
| 4 | Delayed LAA (selective) | axial | 1-2 mm | Thrombus vs slow-flow stasis |
Key points
- PV anatomic variants (common left trunk, accessory right middle vein) occur in up to ~30% — mapping them is a primary purpose of the exam
- A triphasic contrast injection keeps the LA dense while avoiding SVC streak over the right PVs
- Delayed imaging reliably separates LAA thrombus (persistent defect) from stasis (fills in) — do not call thrombus on a single early phase
- Baseline PV ostial measurements enable detection of post-ablation stenosis on follow-up
References
• EHRA/EACVI Clinical Consensus Statement: Pre- and Post-procedural Cardiac Imaging (CT and MRI) in Electrophysiology (Europace 2024) link
• RadioGraphics: Multi–Detector Row CT of the Left Atrium and Pulmonary Veins before Radio-frequency Catheter Ablation for Atrial Fibrillation (Lacomis et al., 2003) link
• Radiopaedia: Pulmonary veins link
• RadioGraphics: Multi–Detector Row CT of the Left Atrium and Pulmonary Veins before Radio-frequency Catheter Ablation for Atrial Fibrillation (Lacomis et al., 2003) link
• Radiopaedia: Pulmonary veins 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.