title: Feasibility and limitations of an automated 2D-3D rigid image registration system for complex endovascular aortic procedures.
abstract: OBJECTIVE
  To examine the feasibility of an automated 2-dimensional (2D) to 3- dimensional (3D) image registration system to simplify the navigational challenges faced in complex endovascular aortic procedures.
  
  
  METHODS
  An automated 2D-3D image registration system was used to overlay pre-acquired 3D computed tomography images onto fluoroscopy images taken during endovascular aneurysm repair. Errors between the 3D overlay and digital subtraction angiograms were measured and correlated with aortic neck angulation. A mean discrepancy < or =3 mm was considered clinically acceptable.
  
  
  RESULTS
  There was a strong correlation between maximum neck angulation and maximum registration error (Pearson's r = 0.75). Aortas with a maximum neck angulation < or =30 degrees had a mean error of 2.5+/-1.2 mm, whereas aortas with neck angulation >30 degrees had a mean error of 6.2+/-2.5 mm (p<0.0001).
  
  
  CONCLUSIONS
  The major source of registration errors is aortic deformation caused by the presence of the introducer and endovascular graft. Further work is required if this technology is to be routinely applied to severely angulated aortic anatomy.
authors.affiliation: King's Health Partners, London, UK. tom.carrell@gstt.nhs.uk
authors.forename: Tom W G
authors.initials: TW
authors.lastname: Carrell
authors.forename: Bijan
authors.initials: B
authors.lastname: Modarai
authors.forename: James R I
authors.initials: JR
authors.lastname: Brown
authors.forename: Graeme P
authors.initials: GP
authors.lastname: Penney
mesh_terms: D015901:Angiography, Digital Subtraction; D001018:Aortic Diseases / Q000000981:diagnostic imaging* / Q000601:surgery; D001027:Aortography / Q000379:methods*; D057205:Automation, Laboratory; D001807:Blood Vessel Prosthesis; D019917:Blood Vessel Prosthesis Implantation / Q000295:instrumentation; D005240:Feasibility Studies; D006801:Humans; D021621:Imaging, Three-Dimensional; D008131:London; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging; D011237:Predictive Value of Tests; D011474:Prosthesis Design; D011857:Radiographic Image Interpretation, Computer-Assisted; D012077:Renal Artery / Q000000981:diagnostic imaging; D012189:Retrospective Studies; D015607:Stents; D025321:Surgery, Computer-Assisted / Q000295:instrumentation; D014057:Tomography, X-Ray Computed