Introduction: The article presents potentials and the role of contrast enhanced MR angiography (MRA) for planning of the interventional ablation in patients with atrial fibrillation and during the follow-up monitoring of pulmonary veins (PV) after this procedure. Due to the minimal invasiveness and the absence of X-ray, MRA is the most suitable method for repeated examinations. However, MRA has lower spatial resolution and usually also worse SNR compared to CT angiography. These factors can be very important in the PV’s caliber quantification. Results: Phantom measurements showed that the error of the cross-sectional area (CSA) determination is below 6% in this ideal case (“in vitro”). The reproducibility of the CSA quantification “in vivo” was 11.2% (group of 6 healthy volunteers). The method of CSA measurement is very important factor for “in vivo” quantification. The change of PV’s caliber should be characterized by measurement of CSA and not by any linear size seen in longitudinal projection. As shown, these two approaches bring significantly different results and so also in case of the quadratic approximation of linear extents (ellipse, triangle). In group of 29 patients, there was found 18 (15%) mild PV’s reductions (50–80% of the original caliber) and 10 (8%) significant stenosis (below 50% of original caliber). Conclusion: The limitation of MRA in the spatial resolution is not very restrictive factor because of PV size and so the method can be very well used for the anatomy assessment before RF ablation and the PV monitoring after this procedure.

        Key words: MR angiography – pulmonary veins – catheter ablation – atrial fibrillation