title: Regional assessment of in vivo myocardial stiffness using 3D magnetic resonance elastography in a porcine model of myocardial infarction.
abstract: OBJECTIVE
  The stiffness of a myocardial infarct affects the left ventricular pump function and remodeling. Magnetic resonance elastography (MRE) is a noninvasive imaging technique for measuring soft-tissue stiffness in vivo. The purpose of this study was to investigate the feasibility of assessing in vivo regional myocardial stiffness with high-frequency 3D cardiac MRE in a porcine model of myocardial infarction, and compare the results with ex vivo uniaxial tensile testing.
  
  
  METHODS
  Myocardial infarct was induced in a porcine model by embolizing the left circumflex artery. Fourteen days postinfarction, MRE imaging was performed in diastole using an echocardiogram-gated spin-echo echo-planar-imaging sequence with 140-Hz vibrations and 3D MRE processing. The MRE stiffness and tensile modulus from uniaxial testing were compared between the remote and infarcted myocardium.
  
  
  RESULTS
  Myocardial infarcts showed increased in vivo MRE stiffness compared with remote myocardium (4.6 ± 0.7 kPa versus 3.0 ± 0.6 kPa, P = 0.02) within the same pig. Ex vivo uniaxial mechanical testing confirmed the in vivo MRE results, showing that myocardial infarcts were stiffer than remote myocardium (650 ± 80 kPa versus 110 ± 20 kPa, P = 0.01).
  
  
  CONCLUSIONS
  These results demonstrate the feasibility of assessing in vivo regional myocardial stiffness with high-frequency 3D cardiac MRE. Magn Reson Med 79:361-369, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
authors.affiliation: Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Shivaram P
authors.initials: SP
authors.lastname: Arunachalam
authors.affiliation: Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Arvin
authors.initials: A
authors.lastname: Arani
authors.affiliation: Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Francis
authors.initials: F
authors.lastname: Baffour
authors.affiliation: Department of Surgery, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Rysavy
authors.affiliation: Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Phillip J
authors.initials: PJ
authors.lastname: Rossman
authors.affiliation: Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Glaser
authors.affiliation: Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: David S
authors.initials: DS
authors.lastname: Lake
authors.affiliation: Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Joshua D
authors.initials: JD
authors.lastname: Trzasko
authors.affiliation: Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Armando
authors.initials: A
authors.lastname: Manduca
authors.affiliation: Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Kiaran P
authors.initials: KP
authors.lastname: McGee
authors.affiliation: Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Richard L
authors.initials: RL
authors.lastname: Ehman
authors.affiliation: Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Philip A
authors.initials: PA
authors.lastname: Araoz
mesh_terms: D000465:Algorithms; D000818:Animals; D055119:Elastic Modulus; D054459:Elasticity Imaging Techniques; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging*; D007090:Image Interpretation, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging; D008297:Male; D009203:Myocardial Infarction / Q000000981:diagnostic imaging*; D011312:Pressure; D011379:Prognosis; D012984:Software; D013314:Stress, Mechanical; D013552:Swine; D013718:Tensile Strength; D013778:Tetrazolium Salts / Q000737:chemistry; D016277:Ventricular Function, Left
chemical_list: D013778:Tetrazolium Salts; C009591:triphenyltetrazolium
keywords: cardiac MRE; cardiac elastography; heart failure; magnetic resonance elastography; myocardial infarction; myocardial stiffness; shear modulus