title: Correlation between transversal and orthogonal maximal diameters of abdominal aortic aneurysms and alternative rupture risk predictors.
abstract: There is no standard for measuring maximal diameter (Dmax) of abdominal aortic aneurysm (AAA) from computer tomography (CT) images although differences between Dmax evaluated from transversal (axialDmax) or orthogonal (orthoDmax) planes can be large especially for angulated AAAs. Therefore we investigated their correlations with alternative rupture risk indicators as peak wall stress (PWS) and peak wall rupture risk (PWRR) to decide which Dmax is more relevant in AAA rupture risk assessment.
  
  
  
  The Dmax values were measured by a trained radiologist from 70 collected CT scans, and the corresponding PWS and PWRR were evaluated using Finite Element Analysis (FEA). The cohort was ordered according to the difference between axialDmax and orthoDmax (Da-o) quantifying the aneurysm angulation, and Spearman's correlation coefficients between PWS/PWRR - orthoDmax/axialDmax were calculated.
  
  
  
  The calculated correlations PWS/PWRR vs. orthoDmax were substantially higher for angulated AAAs (with Da-o≥3mm). Under this limit, the correlations were almost the same for both Dmax values. Analysis of AAAs divided into two groups of angulated (n=38) and straight (n=32) cases revealed that both groups are similar in all parameters (orthoDmax, PWS, PWRR) with the exception of axialDmax (p=0.024).
  
  
  
  It was confirmed that orthoDmax is better correlated with the alternative rupture risk predictors PWS and PWRR for angulated AAAs (DA-O≥3mm) while there is no difference between orthoDmax and axialDmax for straight AAAs (DA-O<3mm). As angulated AAAs represent a significant portion of cases it can be recommended to use orthoDmax as the only Dmax parameter for AAA rupture risk assessment.
authors.affiliation: Institute of Solid Mechanics, Mechatronics and Biomechanics, Brno University of Technology, Czech Republic. Electronic address: kamil.novak@centrum.cz.
authors.forename: Kamil
authors.initials: K
authors.lastname: Novak
authors.affiliation: Institute of Solid Mechanics, Mechatronics and Biomechanics, Brno University of Technology, Czech Republic.
authors.forename: Stanislav
authors.initials: S
authors.lastname: Polzer
authors.affiliation: Department of Medical Imaging, St. Anne´s University Hospital and Faculty of Medicine, Masaryk University, Brno, Czech Republic.
authors.forename: Tomas
authors.initials: T
authors.lastname: Krivka
authors.affiliation: 2(nd) Department of Surgery, St. Anne's University Hospital and Faculty of Medicine, Masaryk University, Brno, Czech Republic.
authors.forename: Robert
authors.initials: R
authors.lastname: Vlachovsky
authors.affiliation: 2(nd) Department of Surgery, St. Anne's University Hospital and Faculty of Medicine, Masaryk University, Brno, Czech Republic.
authors.forename: Robert
authors.initials: R
authors.lastname: Staffa
authors.affiliation: 2(nd) Department of Surgery, St. Anne's University Hospital and Faculty of Medicine, Masaryk University, Brno, Czech Republic.
authors.forename: Lubos
authors.initials: L
authors.lastname: Kubicek
authors.affiliation: Department of Radiology, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague, Czech Republic.
authors.forename: Lukas
authors.initials: L
authors.lastname: Lambert
authors.affiliation: Institute of Solid Mechanics, Mechatronics and Biomechanics, Brno University of Technology, Czech Republic.
authors.forename: Jiri
authors.initials: J
authors.lastname: Bursa
mesh_terms: D017542:Aneurysm, Ruptured / Q000000981:diagnostic imaging* / Q000453:epidemiology* / Q000503:physiopathology; D001012:Aorta, Abdominal / Q000000981:diagnostic imaging*; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging* / Q000453:epidemiology* / Q000503:physiopathology; D000072226:Computed Tomography Angiography / Q000379:methods* / Q000706:statistics & numerical data; D003198:Computer Simulation; D018153:Czech Republic / Q000453:epidemiology; D006801:Humans; D008955:Models, Cardiovascular; D015995:Prevalence; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D018570:Risk Assessment / Q000379:methods; D012680:Sensitivity and Specificity; D013223:Statistics as Topic
keywords: Abdominal aortic aneurysm; Correlation analysis; Maximal diameter; Peak wall rupture risk; Peak wall stress