title: Phase-contrast MRI-based elastography technique detects early hypertensive changes in ex vivo porcine aortic wall.
abstract: OBJECTIVE
  To measure the elastic properties of ex vivo porcine aortas in control and hypertensive groups using a phase contrast magnetic resonance imaging (MRI)-based elastography technique.
  
  
  METHODS
  Female domestic pigs were randomized to a normal control group (N; n=5) or a renovascular hypertension group (HT; n=5) for the duration of 3 months. Mean arterial pressure was significantly higher in the hypertension group than in the control group (173+/-12 vs. 115+/-11 mmHg, P<or=0.05). The animals were euthanized after 3 months of hypertension and abdominal aortas harvested. The ex vivo aortic samples were then examined using a phase-contrast MRI-based elastography technique.
  
  
  RESULTS
  The Young's modulus-wall thickness product, a reflection of vascular stiffness, was significantly higher in the hypertension group than in the control group (0.571+/-0.080 vs. 0.419+/-0.026, P<0.05). Histological analysis and staining confirmed increased intima-media thickness and collagen content in the hypertensive aorta, while elastin staining showed no difference.
  
  
  CONCLUSIONS
  The current study shows that MR elastography offers a method to study the physiologic changes in the arterial wall secondary to early hypertension.
authors.affiliation: Radiology Department, Mayo Clinic, Rochester, Minnesota 55905, USA. Woodrum.david@mayo.edu
authors.forename: David A
authors.initials: DA
authors.lastname: Woodrum
authors.forename: Joerg
authors.initials: J
authors.lastname: Herrmann
authors.forename: Amir
authors.initials: A
authors.lastname: Lerman
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Romano
authors.forename: Lilach O
authors.initials: LO
authors.lastname: Lerman
authors.forename: Richard L
authors.initials: RL
authors.lastname: Ehman
mesh_terms: D000818:Animals; D001012:Aorta, Abdominal / Q000473:pathology / Q000648:ultrastructure; D001794:Blood Pressure; D001835:Body Weight; D002784:Cholesterol / Q000097:blood; D004195:Disease Models, Animal; D054459:Elasticity Imaging Techniques / Q000379:methods*; D005260:Female; D006973:Hypertension / Q000175:diagnosis*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008858:Microscopy, Phase-Contrast; D013552:Swine
chemical_list: D002784:Cholesterol