Magnetic resonance imaging assessment of proteolytic enzyme concentrations and biologic properties of intraluminal thrombus in abdominal aortic aneurysms

J Vasc Surg. 2020 Sep;72(3):1025-1034. doi: 10.1016/j.jvs.2019.11.032. Epub 2020 Feb 14.


Objective: The aim of the study was to determine whether magnetic resonance imaging (MRI) can be used in assessment of biologic activity of intraluminal thrombus (ILT) and proteolytic processes of the abdominal aortic aneurysm wall.

Methods: Using MRI, 50 patients with asymptomatic infrarenal abdominal aortic aneurysm were analyzed at the maximum aneurysm diameter on T1-weighted images in the arterial phase after administration of contrast material. Relative ILT signal intensity (SI) was determined as the ratio between ILT SI and psoas muscle SI. During surgery, the full thickness of the ILT and the adjacent part of the aneurysm wall were harvested at the maximal diameter for biochemical analysis. The concentrations of matrix metalloproteinase 9 and neutrophil elastase (NE/ELA) were analyzed in harvested thrombi, and the concentrations of collagen type III, elastin, and proteoglycans were analyzed in harvested aneurysm walls.

Results: A significant positive correlation was found between the NE/ELA concentration of the ILT and the relative SI (ρ = 0.309; P = .029). Furthermore, a negative correlation was observed between the elastin content of the aneurysm wall and the relative SI (ρ = -0.300; P = .034). No correlations were found between relative SI and concentration of matrix metalloproteinase 9, NE/ELA, collagen type III, or proteoglycan 4 in the aneurysm wall.

Conclusions: These findings indicate a potential novel use of MRI in prediction of thrombus proteolytic enzyme concentrations and the extracellular matrix content of the aneurysm wall, thus providing additional information for the risk of potential aneurysm rupture.

Keywords: Abdominal aortic aneurysm; Elastin; Intraluminal thrombus; Magnetic resonance imaging; Matrix metalloproteinase; Neutrophil elastase.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aorta, Abdominal / diagnostic imaging*
  • Aorta, Abdominal / enzymology
  • Aorta, Abdominal / surgery
  • Aortic Aneurysm, Abdominal / diagnostic imaging*
  • Aortic Aneurysm, Abdominal / enzymology
  • Aortic Aneurysm, Abdominal / surgery
  • Collagen Type III / analysis
  • Cross-Sectional Studies
  • Elastin / analysis
  • Female
  • Humans
  • Leukocyte Elastase / analysis*
  • Magnetic Resonance Imaging*
  • Male
  • Matrix Metalloproteinase 9 / analysis*
  • Middle Aged
  • Predictive Value of Tests
  • Proteoglycans / analysis
  • Proteolysis
  • Thrombosis / diagnostic imaging*
  • Thrombosis / enzymology
  • Thrombosis / surgery


  • Collagen Type III
  • ELN protein, human
  • Proteoglycans
  • Elastin
  • ELANE protein, human
  • Leukocyte Elastase
  • MMP9 protein, human
  • Matrix Metalloproteinase 9