title: Multi-parametric MRI as an indirect evaluation tool of the mechanical properties of in-vitro cardiac tissues.
abstract: BACKGROUND
  Early detection of heart failure is essential to effectively reduce related mortality. The quantification of the mechanical properties of the myocardium, a primordial indicator of the viability of the cardiac tissue, is a key element in patient's care. Despite an incremental utilization of multi-parametric magnetic resonance imaging (MRI) for cardiac tissue characteristics and function, the link between multi-parametric MRI and the mechanical properties of the heart has not been established. We sought to determine the parametric relationship between the myocardial mechanical properties and the MR parameters. The specific aim was to develop a reproducible evaluative quantitative tool of the mechanical properties of cardiac tissue using multi-parametric MRI associated to principal component analysis.
  
  
  METHODS
  Samples from porcine hearts were submitted to a multi-parametric MRI acquisition followed by a uniaxial tensile test. Multi linear regressions were performed between dependent (Young's modulus E) and independent (relaxation times T1, T2 and T2*, magnetization transfer ratio MTR, apparent diffusion coefficient ADC and fractional anisotropy FA) variables. A principal component analysis was used to convert the set of possibly correlated variables into a set of linearly uncorrelated variables.
  
  
  RESULTS
  Values of 46.1 ± 12.7 MPa for E, 729 ± 21 ms for T1, 61 ± 6 ms for T2, 26 ± 7 for T2*, 35 ± 5% for MTR x 100, 33.8 ± 4.7 for FA x 10⁻², and 5.85 ± 0.21 mm²/s for ADC x 10⁻⁴ were measured. Multi linear regressions showed that only 45% of E can be explained by the MRI parameters. The principal component analysis reduced our seven variables to two principal components with a cumulative variability of 63%, which increased to 80% when considering the third principal component.
  
  
  CONCLUSIONS
  The proposed multi-parametric MRI protocol associated to principal component analysis is a promising tool for the evaluation of mechanical properties within the left ventricle in the in vitro porcine model. Our in vitro experiments will now allow us focused in vivo testing on healthy and infracted hearts in order to determine useful quantitative MR-based biomarkers.
authors.affiliation: École Polytechnique, Mechanical Engineering, Montréal, QC, Canada. delphine.perie@polymtl.ca
authors.forename: Delphine
authors.initials: D
authors.lastname: Périé
authors.forename: Nagib
authors.initials: N
authors.lastname: Dahdah
authors.forename: Anthony
authors.initials: A
authors.lastname: Foudis
authors.forename: Daniel
authors.initials: D
authors.lastname: Curnier
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D038524:Diffusion Magnetic Resonance Imaging; D055119:Elastic Modulus; D006321:Heart / Q000502:physiology*; D066298:In Vitro Techniques; D016014:Linear Models; D008955:Models, Cardiovascular; D009200:Myocardial Contraction; D017711:Nonlinear Dynamics; D011237:Predictive Value of Tests; D025341:Principal Component Analysis; D013552:Swine; D013718:Tensile Strength; D016277:Ventricular Function, Left
references.citation: Magn Reson Med. 2007 Sep;58(3):442-7
references.pmid: 17763343
references.citation: BMC Musculoskelet Disord. 2012 Oct 12;13:195
references.pmid: 23061966
references.citation: Circ Res. 1980 Nov;47(5):728-41
references.pmid: 7418131
references.citation: Bioinformatics. 2011 Aug 15;27(16):2288-95
references.pmid: 21737439
references.citation: Circ Cardiovasc Imaging. 2009 May;2(3):206-12
references.pmid: 19808594
references.citation: J Magn Reson Imaging. 2007 Jun;25(6):1283-7
references.pmid: 17520735
references.citation: Magn Reson Med. 2009 Nov;62(5):1155-63
references.pmid: 19780150
references.citation: J Biomech Eng. 2011 Apr;133(4):044501
references.pmid: 21428685
references.citation: Med Eng Phys. 1998 Mar;20(2):103-8
references.pmid: 9679228
references.citation: J Magn Reson Imaging. 1999 Nov;10(5):784-9
references.pmid: 10548789
references.citation: Am J Physiol. 1996 Jan;270(1 Pt 2):H398-410
references.pmid: 8769776
references.citation: J Cardiovasc Magn Reson. 2009 Dec 30;11:56
references.pmid: 20042111
references.citation: Radiology. 1986 Nov;161(2):401-7
references.pmid: 3763909
references.citation: Magn Reson Med. 1999 Apr;41(4):686-95
references.pmid: 10332843
references.citation: J Cardiovasc Magn Reson. 2009 Nov 13;11:47
references.pmid: 19912654
references.citation: J Thorac Cardiovasc Surg. 2009 Apr;137(4):957-62
references.pmid: 19327524
references.citation: J Biomech Eng. 1990 Aug;112(3):340-6
references.pmid: 2214718
references.citation: Med Image Anal. 2009 Oct;13(5):773-84
references.pmid: 19664952
references.citation: Exp Physiol. 2009 May;94(5):578-96
references.pmid: 19098087
references.citation: Med Image Comput Comput Assist Interv. 2006;9(Pt 1):628-35
references.pmid: 17354943
references.citation: J Am Coll Cardiol. 2008 Nov 4;52(19):1574-80
references.pmid: 19007595
references.citation: J Thorac Cardiovasc Surg. 2008 May;135(5):1094-102, 1102.e1-2
references.pmid: 18455590
references.citation: Magn Reson Med. 2010 Oct;64(4):1089-97
references.pmid: 20574967
references.citation: J Cardiovasc Magn Reson. 2010 Nov 19;12:69
references.pmid: 21092095
references.citation: Circulation. 2010 Mar 2;121(8):979-88
references.pmid: 20159832
references.citation: NMR Biomed. 2001 Apr;14(2):57-64
references.pmid: 11320533
references.citation: Magn Reson Med. 2009 Jul;62(1):135-40
references.pmid: 19353657
references.citation: Med Eng Phys. 2009 Jan;31(1):76-82
references.pmid: 18562237
references.citation: J Cardiovasc Magn Reson. 2006;8(3):469-74
references.pmid: 16755833
references.citation: Comput Methods Biomech Biomed Engin. 2006 Oct;9(5):319-41
references.pmid: 17132618
references.citation: J Biomech Eng. 1987 Nov;109(4):298-304
references.pmid: 3695429
references.citation: Invest Radiol. 2007 Nov;42(11):777-89
references.pmid: 18030201
references.citation: J Magn Reson Imaging. 2009 Apr;29(4):832-7
references.pmid: 19306406
references.citation: J Magn Reson Imaging. 2011 May;33(5):1224-8
references.pmid: 21509882
references.citation: J Biomech Eng. 1990 Aug;112(3):333-9
references.pmid: 2214717
references.citation: Comput Methods Biomech Biomed Engin. 2005 Dec;8(6):369-79
references.pmid: 16393874
references.citation: Am J Physiol Heart Circ Physiol. 2005 Aug;289(2):H692-700
references.pmid: 15778283
references.citation: Ann Thorac Surg. 2006 Sep;82(3):840-6
references.pmid: 16928495
references.citation: Magn Reson Med. 2009 Mar;61(3):668-77
references.pmid: 19097236
references.citation: J Physiol Sci. 2009 Sep;59(5):391-6
references.pmid: 19565322
references.citation: Med Eng Phys. 2009 Jan;31(1):83-91
references.pmid: 18539073
references.citation: J Cardiovasc Magn Reson. 2009 Nov 09;11:44
references.pmid: 19900266
references.citation: Ann Thorac Surg. 2001 Feb;71(2):654-62
references.pmid: 11235723
references.citation: Annu Int Conf IEEE Eng Med Biol Soc. 2007;2007:6008-11
references.pmid: 18003383
references.citation: Magn Reson Med. 2007 May;57(5):960-6
references.pmid: 17457877
references.citation: Lancet. 2005 May 28-Jun 3;365(9474):1877-89
references.pmid: 15924986
references.citation: Med Image Comput Comput Assist Interv. 2010;13(Pt 1):418-25
references.pmid: 20879258
references.citation: Magn Reson Med. 2011 May;65(5):1407-15
references.pmid: 21500267
references.citation: J Acoust Soc Am. 2006 Mar;119(3):1880-7
references.pmid: 16583926
references.citation: Med Image Anal. 2012 Aug;16(6):1130-41
references.pmid: 22841777
references.citation: Magn Reson Med. 2005 Sep;54(3):538-48
references.pmid: 16086299
references.citation: Radiology. 2003 Mar;226(3):723-30
references.pmid: 12616019
references.citation: Magn Reson Med. 2005 Oct;54(4):850-9
references.pmid: 16149057
references.citation: MAGMA. 2008 Mar;21(1-2):121-30
references.pmid: 18259791
references.citation: J Biomech Eng. 1998 Aug;120(4):504-17
references.pmid: 10412422
references.citation: Magn Reson Med. 2004 Jul;52(1):141-6
references.pmid: 15236377
references.citation: Magn Reson Med. 2010 Nov;64(5):1520-8
references.pmid: 20677229