title: Three-dimensional ultrasonography measurements after endovascular aneurysm repair.
abstract: BACKGROUND
  Ultrasonographic (US) assessment of abdominal aortic aneurysms is typically performed by measuring maximal aneurysm diameter from two-dimensional images. These measurements are prone to inaccuracies owing to image planes and interobserver variability. The purpose of this study was to compare the variability in diameter, cross-sectional area (CSA), and volume measurements of abdominal aortic aneurysms obtained using a three-dimensional (3D) US imaging system with those obtained using computed tomographic (CT) angiography, and to determine the reliability of these measures.
  
  
  METHODS
  Seven patients in whom endovascular aneurysm repairs were performed underwent CT angiography in addition to a 3D US scan. Measurements computed using 3D surface reconstructions of CT and 3D US scans included maximum diameter, CSA, and aneurysm volume. The seven matched CT and 3D US scans were compared at baseline and 6 to 8 weeks later.
  
  
  RESULTS
  The average aneurysm measured 57.2 mm on CT and 56.2 mm on US (P = 0.14). Correlation coefficients for diameter, CSA, and volume were 0.88, 0.90, and 0.93, respectively (all P values < 0.001). A Bland-Altman analysis demonstrated a strong agreement between 92% of the diameter, 96.4% of the CSA, and 100% of the volume measurements. The interrater reliability was remarkably high comparing the modalities (CT vs. US), and ranged from 0.934 to 0.997 for single measurements and 0.965 to 0.998 for all measurements together; moreover, there was a strong reliability when the tests were reviewed 6 to 8 weeks later, with a reliability of 0.962 to 0.998 for single measurements and 0.992 to 0.999 for all tests (all P values < 0.001).
  
  
  CONCLUSIONS
  The 3D US is an accurate and noninvasive method of determining aneurysm size and geometry that is reproducible. Volumetric measurements may represent a significant advancement in long-term follow-up after endovascular aneurysm repair.
authors: Department of Surgery, University of Washington, Seattle, WA 98195, USA. mwcausey@msn.com
authors: Marlin Wayne
authors: MW
authors: Causey
authors: Arjun
authors: A
authors: Jayaraj
authors: Daniel F
authors: DF
authors: Leotta
authors: Marla
authors: M
authors: Paun
authors: Kirk W
authors: KW
authors: Beach
authors: Ted R
authors: TR
authors: Kohler
authors: Eugene R
authors: ER
authors: Zierler
authors: Benjamin W
authors: BW
authors: Starnes
mesh_terms: D001012:Aorta, Abdominal / Q000000981:diagnostic imaging / Q000601:surgery*; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging / Q000601:surgery*; D001027:Aortography / Q000379:methods; D019917:Blood Vessel Prosthesis Implantation; D057510:Endovascular Procedures; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D021621:Imaging, Three-Dimensional; D015588:Observer Variation; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D014463:Ultrasonography