Comparing Image-Based Respiratory Motion Correction Methods for Anatomical Roadmap Guided Cardiac Electrophysiology Procedures

X-ray fluoroscopically guided cardiac electrophysiological procedures are routinely carried out for diagnosis and treatment of cardiac arrhythmias. X-ray images have poor soft tissue contrast and, for this reason, overlay of static 3D roadmaps derived from pre-procedural volumetric data can be used to add anatomical information. However, the registration between the 3D roadmap and the 2D X-ray data can be compromised by patient respiratory motion. Three methods were evaluated to correct for respiratory motion using features in the X-ray image data. The first method is based on tracking either the diaphragm or the heart border using the image intensity in a region of interest. The second method detects the tracheal bifurcation using the generalized Hough transform and a 3D model derived from pre-operative image data. The third method is based on tracking the coronary sinus (CS) catheter. All three methods were applied to X-ray images from 18 patients undergoing radiofrequency ablation for the treatment of atrial fibrillation. The 2D target registration errors (TRE) at the pulmonary veins were calculated to validate the methods. A TRE of 1.6 mm ± 0.8 mm was achieved for the diaphragm tracking; 1.7 mm ± 0.9 mm for heart border tracking; 1.9 mm ± 1.0 mm for trachea tracking and 1.8 mm ± 0.9 mm for CS catheter tracking. We also present a comparison between our techniques with other published image-based motion correction strategies

Comparison of Low-order 4D Dynamical Models for Cardiac Respiratory Motion using MRI

Projecte final de carrera elaborat en col·laboració amb Northeastern UniversityEnglish: cardiovascular diseases account for more than one third of the annual mortal rate in western countries. Although AF does not directly lead to mortality is pointed as one of the possible causes of stroke. Recent developments in catheter intervention open promising surgical treatments for this disease, although the clinical and technical challenges must be overcome for it to become standard. Movement of the heart because of cardiac and respiratory movement complicate the positioning of the catheter inside the heart. The aim of this project is to purpose and test models for automatically segmenting and tracking the heart in 4D cardiac MRI datasets, for potential use in in surgery training, planning and guidance.Castellano: las enfermedades cardiovasculares són las causantes de un tercio de las muertes en los países occidentales. A pesar que la fibrilación del atria no és causante directa de muerte, ha sido señalada como una de las posibles causas de embolia. Mejoras recientes en las intervenciones con catéter muestran prometedores tratamientos para esta enfermedad. A pesar de ello, antes hay que solventar un conjunto de dificultades técnicas. El movimiento del corazón debido al própio latido y a la respiración dificultan el posizionamiento del catéter dentro del corazón. El objeto de este proyecto es el de testear y comparar modelos de segmentación y seguimiento en 4D del corazón mediante imágenes de RM de forma automática. Con el objetivo potencial de su aplicación en preparación, práctica y intervención quirúrgica.Català: les malalties cardiovasculars són les causants d'un terç de les morts als països occidentals. Tot i que la fibril·lació atrial no és causant directa de mort, ha estat senyalada com una de les possibles causes d'embòlia. Millores recents en intervencions quirúrgiques amb catèters obren prometedors tractaments per a aquesta malaltia. A pesar d'això, un seguit de problemes tècniqus han de ser resolts. El moviment del cor tant pel bateg del mateix com el provocat per la respiració compliquen el posicionament del catèter dins del cor. Lóbjectiu d'aquest projecte és el de testejar i comparar models que segmenten i segueixen al cor en 4D basats en imatges de RM de forma automàtica amb l'objectiu potencial d'aplicar-los en la preparació, pràctica i guiat de les intervencions quirúrgiques