title: Optimized viewing angles for cardiac electrophysiology ablation procedures.
abstract: OBJECTIVE
  Catheter ablation is a common treatment option for atrial fibrillation (AF). Interventional C-arm X-ray systems are used for guiding AF procedures, employing standard view positions. Since the projection angles are not adapted to the individual patient anatomy, standard projections do not necessarily offer the best views of important anatomical structures. Using a pre-procedural 3D data set acquired with MRI or CT, suitable ablation sites (lines) can be identified in advance so an ablation plan can be superimposed on fluoroscopic images to guide the procedure.
  
  
  METHODS
  A method was developed to estimate optimized projection views for biplane X-ray C-arm systems based on planning data for AF ablation procedures. The estimated viewing angles were compared to standard angulations using an objective quality metric, the length of the planned ablation line as seen under X-ray. This method was tested using 35 clinical datasets annotated with planned ablation lines for ipsilateral pulmonary vein isolation.
  
  
  RESULTS
  The optimized views computed using the new method yielded 28 % less foreshortening of pre-planned ablation lines on average. In one case, anatomy-based view calculation lead to a 69 % reduction in foreshortening.
  
  
  CONCLUSIONS
  The commonly used standard views provide reasonable a priori choices, and some improvement is possible by switching among common angulations depending on the treatment region. Further gains are possible by using anatomy-optimized biplane C-arm angulations.
authors.affiliation: Pattern Recognition Lab, Friedrich-Alexander-Universität Erlangen-Nürnberg, Martensstr. 3, 91058 , Erlangen, Germany, Martin.Koch@cs.fau.de.
authors.forename: Martin
authors.initials: M
authors.lastname: Koch
authors.forename: Matthias
authors.initials: M
authors.lastname: Hoffmann
authors.forename: Marcus
authors.initials: M
authors.lastname: Pfister
authors.forename: Joachim
authors.initials: J
authors.lastname: Hornegger
authors.forename: Norbert
authors.initials: N
authors.lastname: Strobel
mesh_terms: D001281:Atrial Fibrillation / Q000000981:diagnostic imaging / Q000473:pathology / Q000628:therapy*; D017115:Catheter Ablation / Q000379:methods*; D022062:Electrophysiologic Techniques, Cardiac / Q000379:methods*; D006801:Humans; D008279:Magnetic Resonance Imaging; D015641:Radiography, Interventional; D014057:Tomography, X-Ray Computed / Q000379:methods*; D016896:Treatment Outcome
references.citation: Herz. 2008 Dec;33(8):580-4
references.pmid: 19137248
references.citation: Int J Cardiovasc Imaging. 2009 Jun;25(5):455-62
references.pmid: 19101820
references.citation: Eur Heart J Cardiovasc Imaging. 2012 Feb;13(2):132-8
references.pmid: 21903725
references.citation: J Cardiovasc Electrophysiol. 2013 Feb;24(2):113-20
references.pmid: 23131083
references.citation: Circulation. 2012 Jul 10;126(2):223-9
references.pmid: 22777665
references.citation: J Med Imaging (Bellingham). 2014 Apr;1(1):015002
references.pmid: 26158027
references.citation: IEEE Trans Med Imaging. 1994;13(1):13-24
references.pmid: 18218480
references.citation: IEEE Trans Med Imaging. 2000 Apr;19(4):318-36
references.pmid: 10909927
references.citation: Eur Heart J. 2007 Sep;28(18):2231-7
references.pmid: 17569680
references.citation: Circulation. 2000 Mar 28;101(12):1409-17
references.pmid: 10736285
references.citation: Catheter Cardiovasc Interv. 2005 Apr;64(4):451-9
references.pmid: 15744720
references.citation: JACC Cardiovasc Interv. 2010 Nov;3(11):1157-65
references.pmid: 21087752
references.citation: IEEE Trans Med Imaging. 2005 Nov;24(11):1512-24
references.pmid: 16279087
references.citation: Europace. 2010 Jan;12(1):37-44
references.pmid: 19919969