title: Prediction of aortoiliac stent-graft length: comparison of measurement methods.
abstract: OBJECTIVE
  To determine the accuracy of helical computed tomography (CT), projectional angiography derived from CT angiography, and intravascular ultrasonographic withdrawal (IUW) length measurements for predicting appropriate aortoiliac stent-graft length.
  
  
  METHODS
  Helical CT data from 33 patients were analyzed before and after endovascular repair of abdominal aortic aneurysm (Aneuryx graft, n = 31; Excluder graft, n = 2). The aortoiliac length of the median luminal centerline (MLC) and the shortest path (SP) that remained at least one common iliac arterial radius away from the vessel wall were calculated. Conventional angiographic measurements were simulated from CT data as the length of the three-dimensional MLC projected onto four standard viewing planes. These predeployment lengths and IUW length, available in 24 patients, were compared with the aortoiliac arterial length after stent-graft deployment.
  
  
  RESULTS
  The mean error values of SP, MLC, the maximum projected MLC, and IUW were -2.1 mm +/- 4.6 (SD) (P =.013), 9.8 mm +/- 6.8 (P <.001), -5.2 mm +/- 7.8 (P <.001), and -14.1 mm +/- 9.3 (P <.001), respectively. The preprocedural prediction of the postprocedural aortoiliac length with the SP was significantly more accurate than that with the MLC (P <.001), maximum projected MLC (P <.001), and IUW (P <.001).
  
  
  CONCLUSIONS
  The shortest aortoiliac path length maintaining at least one radius distance from the vessel wall most accurately enabled stent-graft length prediction for 31 AneuRx and two Excluder stent-grafts.
authors.affiliation: Department of Radiology, Stanford University School of Medicine, S-072B, 300 Pasteur Dr, Stanford, CA 94305-5105, USA.
authors.forename: M
authors.initials: M
authors.lastname: Tillich
authors.forename: B B
authors.initials: BB
authors.lastname: Hill
authors.forename: D S
authors.initials: DS
authors.lastname: Paik
authors.forename: K
authors.initials: K
authors.lastname: Petz
authors.forename: S
authors.initials: S
authors.lastname: Napel
authors.forename: C K
authors.initials: CK
authors.lastname: Zarins
authors.forename: G D
authors.initials: GD
authors.lastname: Rubin
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000792:Angiography; D001012:Aorta, Abdominal / Q000601:surgery*; D017544:Aortic Aneurysm, Abdominal / Q000601:surgery; D001807:Blood Vessel Prosthesis; D005260:Female; D006801:Humans; D007083:Iliac Artery / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D015607:Stents; D014057:Tomography, X-Ray Computed; D018084:Ultrasonography, Interventional