Usefulness of multidetector computed tomography before and after pulmonary vein isolation. / Utilidad de la tomografía computarizada multidetector en la evaluación previa y el seguimiento de los pacientes sometidos a ablación de venas pulmonares.

OBJECTIVE: To analyze the usefulness of multidetector computed tomography (MDCT) in the preprocedural evaluation and follow-up of patients undergoing radiofrequency ablation of pulmonary veins and the impact of the MDCT findings on the approach to treatment. METHOD: We retrospectively analyzed 92 consecutive MDCT studies done in 80 patients between January 2011 and June 2013; 70 (76%) studies were done before a first ablation procedure and 22 (24%) were done in patients who had undergone an ablation procedure. RESULTS: Findings were useful in 34% of the patients who underwent MDCT before the first ablation procedure and in 68% of the studies done after a procedure. The incidence of stroke associated with the ablation procedure was 3%, similar to the incidence recorded in our center before we started to use MDCT to evaluate the anatomy of the left atrium. All symptomatic patients had some pulmonary vein stenosis, and 80% had significant stenosis. Furthermore, the stenoses progressed very rapidly; treatment with balloon angioplasty was associated with early restenosis. Stenting was an alternative in cases of failed angioplasty. CONCLUSION: In the preprocedural evaluation and postprocedural follow-up of patients undergoing pulmonary vein isolation, MDCT is useful for guiding treatment and detecting complications.

Multi-Stencil Streamline Fast Marching: A General 3-D Framework to Determine Myocardial Thickness and Transmurality in Late Enhancement Images.

We propose a fully 3-D methodology for the computation of myocardial nonviable tissue transmurality in contrast enhanced magnetic resonance images. The outcome is a continuous map defined within the myocardium where not only current state-of-the-art measures of transmurality can be calculated, but also information on the location of nonviable tissue is preserved. The computation is done by means of a partial differential equation framework we have called multi-stencil streamline fast marching. Using it, the myocardial and scarred tissue thickness is simultaneously computed. Experimental results show that the proposed 3-D method allows for the computation of transmurality in myocardial regions where current 2-D methods are not able to as conceived, and it also provides more robust and accurate results in situations where the assumptions on which current 2-D methods are based-i.e., there is a visible endocardial contour and its corresponding epicardial points lie on the same slice-, are not met.