title: Feasibility and validation of registration of three-dimensional left atrial models derived from computed tomography with a noncontact cardiac mapping system.
abstract: OBJECTIVE
  The purpose of this study was to determine the feasibility and assess the validity of registering three-dimensional (3D) models from computed tomographic (CT) images using a cardiac mapping system.
  
  
  BACKGROUND
  Registration of 3D anatomic models with an interventional system could help identify and navigate mapping and ablation catheters over a complex structure such as the left atrium (LA).
  
  
  METHODS
  ECG-gated, contrast-enhanced cardiac CT imaging was performed in 14 patients with atrial fibrillation. Segmentation was used to create 3D models of the LA. The 3D models were registered with the mapping system using a series of fiducial points. Registration was accomplished retrospectively in the first 10 patients, and catheter navigation was visualized from recorded data. In the final four patients, registration was accomplished in real time during electrophysiologic study. The mapping catheter position, as it was navigated inside the LA, was applied to the registered model in real time. For the validation study, temporary pacing leads were implanted in the LA of 10 dogs. Following this, CT scanning, segmentation, LA model importation, and registration was described previously. After registration, a mapping catheter was positioned at the site of each buried lead according to the registered model with no fluoroscopic guidance. A radiofrequency lesion was created at this location, and the dog was sacrificed, the heart removed and stained, and the distance between the buried lead and the lesion measured.
  
  
  RESULTS
  During the feasibility study, the location of the catheter in the registered model correlated with fluoroscopy, angiography, and intracardiac electrograms. LA endocardial potentials during sinus rhythm and any premature atrial contractions also were successfully delineated over the registered models. In the validation study, the mean target registration error was 2.0 +/- 3.6 mm.
  
  
  CONCLUSIONS
  Registration of CT-derived 3D models of the LA using a cardiac mapping system is feasible and accurate.
authors.affiliation: Electrophysiology Laboratories of Aurora Sinai and St. Luke's Medical Centers, University of Wisconsin Medical School-Milwaukee Clinical Campus, USA. bdanek@htcare.com
authors.forename: Jasbir
authors.initials: J
authors.lastname: Sra
authors.forename: David
authors.initials: D
authors.lastname: Krum
authors.forename: John
authors.initials: J
authors.lastname: Hare
authors.forename: Darin
authors.initials: D
authors.lastname: Okerlund
authors.forename: Helen
authors.initials: H
authors.lastname: Thompson
authors.forename: Melissa
authors.initials: M
authors.lastname: Vass
authors.forename: Jeff
authors.initials: J
authors.lastname: Schweitzer
authors.forename: Eric
authors.initials: E
authors.lastname: Olson
authors.forename: W Dennis
authors.initials: WD
authors.lastname: Foley
authors.forename: Masood
authors.initials: M
authors.lastname: Akhtar
mesh_terms: D000818:Animals; D001281:Atrial Fibrillation / Q000000981:diagnostic imaging; D016279:Atrial Function, Left; D006328:Cardiac Catheterization; D004285:Dogs; D004562:Electrocardiography; D022062:Electrophysiologic Techniques, Cardiac; D005240:Feasibility Studies; D005260:Female; D006325:Heart Atria / Q000033:anatomy & histology*; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D014057:Tomography, X-Ray Computed