title: Quantitative assessment of asymmetric aortic dilation with valve-related aortic disease.
abstract: OBJECTIVE
  Previous work suggests that ascending aortic (AsAo) dilation can be asymmetric and is potentially related to valve-related blood flow abnormalities. The aim of this study was to investigate the relationship between the aortic valve and AsAo dilation using a quantitative, three-dimensional assessment of aortic shapes.
  
  
  METHODS
  Computed tomographic and magnetic resonance images of the thorax were retrospectively reviewed. Four groups with aortic dilation were studied: those with tricuspid aortic valves (TAVs) with and without stenosis and those with bicuspid aortic valves (BAVs) with and without stenosis. Controls had either TAVs or BAVs but no aortic stenosis or dilation. In additional to standard orthogonal diameters, a unique measurement of AsAo asymmetry was used: the ratio of the greater to lesser curvatures measured using three-dimensional reformats in a "candy-cane" orientation.
  
  
  RESULTS
  A total of 105 patients were identified. Ratios of greater to lesser curvature in patients with aortic dilation and nonstenotic TAVs were not significantly different from those in controls (1.69 vs 1.55, P > .20), but the asymmetry reflected by this ratio was markedly increased in patients with aortic dilation and stenotic TAVs (1.94, P < .001). Patients with aortic dilation and BAVs had significantly elevated ratios regardless of the status of the aortic valve (1.96 for nonstenotic and 2.05 for stenotic vs 1.53 for controls, P < .001).
  
  
  CONCLUSIONS
  Asymmetric AsAo dilation with relative bulging of the greater curvature is linked to aortic stenosis, but it is also seen with nonstenotic BAVs. This suggests that the hemodynamic forces that contribute to aortic dilation are not fully revealed by conventional assessment of the aortic valve.
authors.affiliation: Department of Radiology, University of California, San Francisco, San Francisco, CA 94143-0628, USA.
authors.forename: Michael T
authors.initials: MT
authors.lastname: Lu
authors.forename: Samir R
authors.initials: SR
authors.lastname: Thadani
authors.forename: Michael D
authors.initials: MD
authors.lastname: Hope
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D001011:Aorta / Q000473:pathology*; D001018:Aortic Diseases / Q000175:diagnosis* / Q000000981:diagnostic imaging; D001021:Aortic Valve / Q000473:pathology; D003287:Contrast Media; D004108:Dilatation, Pathologic / Q000175:diagnosis / Q000000981:diagnostic imaging; D005260:Female; D019786:Gadolinium DTPA; D006349:Heart Valve Diseases / Q000175:diagnosis* / Q000000981:diagnostic imaging; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D021621:Imaging, Three-Dimensional; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D014261:Tricuspid Valve / Q000473:pathology
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA