Software Framework to Quantify Pulmonary Vein Isolation Atrium Scar Tissue

Pulmonary vein isolation (PVI) is a recommended treatment for drug refractory atrial fibrillation (AF). The ablation causes non-conductive scar tissue that separates the body of the atrium from regions around the pulmonary veins that trigger AF. This scar tissue can be seen in the atrium using cardiac MR. We aim to develop a systematic workflow to quantify the location and size of scar tissue due to PVI from CMR images to evaluate ablation procedures. Input meshes were created from segmented late-gadolineum-enhanced (LGE) cardiac magnetic resonance (CMR) scans with scalar values at each node representing the signal intensity of the scar. The software has three features: (i) Calculating the area of the scar tissue, (ii) assessing ablation lesions to identify the percentage of the pulmonary vein encircled by scar and the number of gaps in it, and (iii) comparing pre- and post-ablation scar tissues qualitatively. Six patients were assessed as a proof of concept, where patients had undergone pre- and post-ablation scans. In all tests, an increase in fibrotic tissue was found, from averages of 2+1.9% and 36+18%. Post-ablation lesions were assessed showing an average of 75+12%_pulmonary vein encirclement, with gaps ranging from 2 to 4. The software presented is a semi-automated, user friendly framework where users are able to assess an ablation procedure.