title: Quantitative assessment of abdominal aortic aneurysm geometry.
abstract: Recent studies have shown that the maximum transverse diameter of an abdominal aortic aneurysm (AAA) and expansion rate are not entirely reliable indicators of rupture potential. We hypothesize that aneurysm morphology and wall thickness are more predictive of rupture risk and can be the deciding factors in the clinical management of the disease. A non-invasive, image-based evaluation of AAA shape was implemented on a retrospective study of 10 ruptured and 66 unruptured aneurysms. Three-dimensional models were generated from segmented, contrast-enhanced computed tomography images. Geometric indices and regional variations in wall thickness were estimated based on novel segmentation algorithms. A model was created using a J48 decision tree algorithm and its performance was assessed using ten-fold cross validation. Feature selection was performed using the χ2-test. The model correctly classified 65 datasets and had an average prediction accuracy of 86.6% (κ=0.37). The highest ranked features were sac length, sac height, volume, surface area, maximum diameter, bulge height, and intra-luminal thrombus volume. Given that individual AAAs have complex shapes with local changes in surface curvature and wall thickness, the assessment of AAA rupture risk should be based on the accurate quantification of aneurysmal sac shape and size.
authors.affiliation: Biomedical Engineering Department, Carnegie Mellon University, 1210 Hamburg Hall, 5000 Forbes Avenue, Pittsburgh, PA 15213, USA.
authors.forename: Judy
authors.initials: J
authors.lastname: Shum
authors.forename: Giampaolo
authors.initials: G
authors.lastname: Martufi
authors.forename: Elena
authors.initials: E
authors.lastname: Di Martino
authors.forename: Christopher B
authors.initials: CB
authors.lastname: Washington
authors.forename: Joseph
authors.initials: J
authors.lastname: Grisafi
authors.forename: Satish C
authors.initials: SC
authors.lastname: Muluk
authors.forename: Ender A
authors.initials: EA
authors.lastname: Finol
mesh_terms: D001012:Aorta, Abdominal / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging / Q000473:pathology*; D001019:Aortic Rupture / Q000000981:diagnostic imaging / Q000473:pathology*; D003198:Computer Simulation; D005260:Female; D006801:Humans; D008297:Male; D008953:Models, Anatomic; D008955:Models, Cardiovascular; D011859:Radiography