title: High Resolution Strain Analysis Comparing Aorta and Abdominal Aortic Aneurysm with Real Time Three Dimensional Speckle Tracking Ultrasound.
abstract: OBJECTIVE
  Ultrasound measurement of aortic diameter for aneurysm screening allows supervision of aneurysm growth. Additional biomechanical analysis of wall motion and aneurysm deformation can supply information about individual elastic properties and the pathological state of the aortic wall. Local aortic wall motion was analyzed through imaged aortic segments according to age and pathology.
  
  
  METHODS
  Sixty-five patients were examined with a commercial four dimensional ultrasound system (4D-US). Three groups were defined: patients with normal aortic diameter and younger than 60 years of age (n = 21); those with normal aortic diameter and older than 60 years of age (n = 25); and those with infrarenal aortic aneurysm (n = 19). A diastolic reference shape of aortic wall segments was obtained and local and temporally resolved wall strain was determined. Indices characterizing the resulting wall strain distribution were determined.
  
  
  RESULTS
  The analysis of biomechanical properties displayed increasing heterogeneous and dyssynchronous circumferential strain with increasing patient age. Young patients exhibited higher mean strain amplitude. The distribution of the spatial heterogeneity index and local strain ratio was inversely proportional to age. The maximum local strain amplitude was significantly higher in the young (0.26 ± 0.17) compared with the old (0.16 ± 0.07) or aneurysmal aorta (0.16 ± 0.10). Temporal dyssynchrony significantly differed between young (0.13 ± 0.10) and old (aneurysmal 0.31 ± 0.04, non-aneurysmal 0.29 ± 0.05), regardless of aortic diameter. The spatial heterogeneity index and local strain ratio differentiate non-aneurysmal and aneurysmal aorta, regardless of age.
  
  
  CONCLUSIONS
  4D-US strain imaging enables description of individual wall motion (kinematics) of the infrarenal aorta with high spatial and temporal resolution. Functional differences between young, old, and aneurysmal aorta can be described by mean (circumferential) strain amplitude, the spatial heterogeneity index, and the local strain ratio. Further investigation is required to refine this new perspective of patient individualized characterization of the pathological AAA wall and eventually to rupture risk stratification.
authors.affiliation: Department of Vascular and Endovascular Surgery, J.W. Goethe University, Theodor-Stern-Kai 7, 60590 Frankfurt/Main, Germany. Electronic address: wojciech.derwich@kgu.de.
authors.forename: W
authors.initials: W
authors.lastname: Derwich
authors.affiliation: Institute for Cell Biology and Neuroscience, J.W. Goethe University, Max-von-Laue-Str. 13, 60438 Frankfurt/Main, Germany; Department of Mechanical Engineering, University Siegen, Paul-Bonatz-Str. 9-11, 57068 Siegen, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Wittek
authors.affiliation: Department of General, Visceral, Vascular and Endovascular Surgery, University Hospital Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Pfister
authors.affiliation: Department of Vascular and Endovascular Surgery, J.W. Goethe University, Theodor-Stern-Kai 7, 60590 Frankfurt/Main, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Nelson
authors.affiliation: Institute for Cell Biology and Neuroscience, J.W. Goethe University, Max-von-Laue-Str. 13, 60438 Frankfurt/Main, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Bereiter-Hahn
authors.affiliation: Department of General, Visceral, Vascular and Endovascular Surgery, University Hospital Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg, Germany.
authors.forename: C P
authors.initials: CP
authors.lastname: Fritzen
authors.affiliation: Institute for Cell Biology and Neuroscience, J.W. Goethe University, Max-von-Laue-Str. 13, 60438 Frankfurt/Main, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Blase
authors.affiliation: Department of Vascular and Endovascular Surgery, J.W. Goethe University, Theodor-Stern-Kai 7, 60590 Frankfurt/Main, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Schmitz-Rixen
mesh_terms: D000367:Age Factors; D000465:Algorithms; D001012:Aorta, Abdominal / Q000000981:diagnostic imaging* / Q000503:physiopathology; D017544:Aortic Aneurysm, Abdominal / Q000150:complications / Q000000981:diagnostic imaging* / Q000503:physiopathology; D001019:Aortic Rupture / Q000209:etiology; D001696:Biomechanical Phenomena; D016022:Case-Control Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012039:Regional Blood Flow; D018570:Risk Assessment; D012307:Risk Factors; D013314:Stress, Mechanical; D014463:Ultrasonography
keywords: 4D ultrasound; Abdominal aortic aneurysm; Aortic wall; Speckle tracking; Strain imaging