Correlation of biomechanics to tissue reaction in aortic aneurysms assessed by finite elements and [18F]-fluorodeoxyglucose-PET/CT

Andreas Maier, Markus Essler, Michael W. Gee, Hans Henning Eckstein, Wolfgang A. Wall, Christian Reeps

Research output: Contribution to journalArticlepeer-review

22 Scopus citations

Abstract

Mechanobiological interactions are essential for the adaption of the cardiovascular system to altered environmental and internal conditions, but are poorly understood with regard to abdominal aortic aneurysm (AAA) pathogenesis, growth and rupture. In the present study, we therefore calculated mechanical AAA quantities using nonlinear finite element methods and correlated these to [18F]-fluorodeoxyglucose (FDG)-metabolic activity in the AAA wall detected by positron emission tomography/computed tomography (PET/CT). The interplay between mechanics and FDG-metabolic activity was analyzed in terms of maximum values and the three-dimensional spatial relationship, respectively. Fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) data sets of n=18 AAA patients were studied. Maximum FDG-uptake (SUV max) in the AAA wall varied from 1.32 to 4.60 (average SUV max 3.31 ±0.87). Maximum wall stresses and strains ranged from 10.0 to 64.0N/cm 2 (38.2 ±13.8N/cm 2) and from 0.190 to 0.260 (0.222 ±0.023), respectively. SUV max was significantly correlated to maximum wall stress and strain (SUV max to stress: r=0.71,p=0.0005; SUV max to strain: r=0.66,p=0.0013). To evaluate the three-dimensional spatial interaction between FDG-uptake and acting wall stress, element-wise correlations were performed. In all but 2 AAAs, positive element-wise correlation of FDG-uptake to wall stress was obtained, with the Pearson's correlation coefficient ranging from -0.168 to 0.738 (0.372 ±0.263). The results indicate that mechanical stresses are correlated quantitatively and spatially to FDG-uptake in the AAA wall. It is hypothesized that unphysiologically increased loading in the AAA wall triggers biological tissue reaction, such as inflammation or regenerative processes, causing elevated FDG-metabolic activity. These findings strongly support experimental hypotheses of mechanotransduction mechanisms in vivo.

Original languageEnglish
Pages (from-to)456-471
Number of pages16
JournalInternational Journal for Numerical Methods in Biomedical Engineering
Volume28
Issue number4
DOIs
StatePublished - Apr 2012

Keywords

  • Abdominal aortic aneurysm
  • FDG-PET/CT
  • Finite element analysis
  • Inflammation
  • Mechanotransduction
  • Metabolic activity

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