Valéry Ozenne1,2, Solenn Toupin1,2,3, Pierre Bour1,2, Baudouin Denis de Senneville4, Matthieu Lepetit-Coiffé3, Manuel Boissenin1,2, Jenny Benois-Pineau5, Michael S Hansen6, Souheil J Inati7, Assaf Govari8, Pierre Jaïs1,9, Bruno Quesson1,2. 1. Institut Hospitalo-Universitaire, Liryc Institut de Rythmologie et Modélisation Cardiaque, Fondation Bordeaux Université, Bordeaux, France. 2. Inserm U1045 Centre de Recherche Cardio-Thoracique de Bordeaux, Université de Bordeaux, Bordeaux, France. 3. Siemens Healthcare France, Saint Denis, France. 4. Mathematical Institute of Bordeaux, Bordeaux, France. 5. LaBRI, CNRS, Université of Bordeaux. 6. Magnetic Resonance Technology Program, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA. 7. National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland, USA. 8. Biosense Webster, Diamond Bar, California, USA. 9. Centre Hospitalier Universitaire de Bordeaux, Bordeaux, France.
Abstract
PURPOSE: A new real-time MR-thermometry pipeline was developed to measure multiple temperature images per heartbeat with 1.6×1.6×3 mm3 spatial resolution. The method was evaluated on 10 healthy volunteers and during radiofrequency ablation (RFA) in sheep. METHODS: Multislice, electrocardiogram-triggered, echo-planar imaging was combined with parallel imaging, under free breathing conditions. In-plane respiratory motion was corrected on magnitude images by an optical flow algorithm. Motion-related susceptibility artifacts were compensated on phase images by an algorithm based on Principal Component Analysis. Correction of phase drift and temporal filter were included in the pipeline implemented in the Gadgetron framework. Contact electrograms were recorded simultaneously with MR thermometry by an MR-compatible ablation catheter. RESULTS: The temporal standard deviation of temperature in the left ventricle remained below 2 °C on each volunteer. In sheep, focal heated regions near the catheter tip were observed on temperature images (maximal temperature increase of 38 °C) during RFA, with contact electrograms of acceptable quality. Thermal lesion dimensions at gross pathology were in agreement with those observed on thermal dose images. CONCLUSION: This fully automated MR thermometry pipeline (five images/heartbeat) provides direct assessment of lesion formation in the heart during catheter-based RFA, which may improve treatment of cardiac arrhythmia by ablation. Magn Reson Med 77:673-683, 2017.
PURPOSE: A new real-time MR-thermometry pipeline was developed to measure multiple temperature images per heartbeat with 1.6×1.6×3 mm3 spatial resolution. The method was evaluated on 10 healthy volunteers and during radiofrequency ablation (RFA) in sheep. METHODS: Multislice, electrocardiogram-triggered, echo-planar imaging was combined with parallel imaging, under free breathing conditions. In-plane respiratory motion was corrected on magnitude images by an optical flow algorithm. Motion-related susceptibility artifacts were compensated on phase images by an algorithm based on Principal Component Analysis. Correction of phase drift and temporal filter were included in the pipeline implemented in the Gadgetron framework. Contact electrograms were recorded simultaneously with MR thermometry by an MR-compatible ablation catheter. RESULTS: The temporal standard deviation of temperature in the left ventricle remained below 2 °C on each volunteer. In sheep, focal heated regions near the catheter tip were observed on temperature images (maximal temperature increase of 38 °C) during RFA, with contact electrograms of acceptable quality. Thermal lesion dimensions at gross pathology were in agreement with those observed on thermal dose images. CONCLUSION: This fully automated MR thermometry pipeline (five images/heartbeat) provides direct assessment of lesion formation in the heart during catheter-based RFA, which may improve treatment of cardiac arrhythmia by ablation. Magn Reson Med 77:673-683, 2017.