title: Accelerated acquisition of tagged MRI for cardiac motion correction in simultaneous PET-MR: phantom and patient studies.
abstract: OBJECTIVE
  Degradation of image quality caused by cardiac and respiratory motions hampers the diagnostic quality of cardiac PET. It has been shown that improved diagnostic accuracy of myocardial defect can be achieved by tagged MR (tMR) based PET motion correction using simultaneous PET-MR. However, one major hurdle for the adoption of tMR-based PET motion correction in the PET-MR routine is the long acquisition time needed for the collection of fully sampled tMR data. In this work, the authors propose an accelerated tMR acquisition strategy using parallel imaging and/or compressed sensing and assess the impact on the tMR-based motion corrected PET using phantom and patient data.
  
  
  METHODS
  Fully sampled tMR data were acquired simultaneously with PET list-mode data on two simultaneous PET-MR scanners for a cardiac phantom and a patient. Parallel imaging and compressed sensing were retrospectively performed by GRAPPA and kt-FOCUSS algorithms with various acceleration factors. Motion fields were estimated using nonrigid B-spline image registration from both the accelerated and fully sampled tMR images. The motion fields were incorporated into a motion corrected ordered subset expectation maximization reconstruction algorithm with motion-dependent attenuation correction.
  
  
  RESULTS
  Although tMR acceleration introduced image artifacts into the tMR images for both phantom and patient data, motion corrected PET images yielded similar image quality as those obtained using the fully sampled tMR images for low to moderate acceleration factors (<4). Quantitative analysis of myocardial defect contrast over ten independent noise realizations showed similar results. It was further observed that although the image quality of the motion corrected PET images deteriorates for high acceleration factors, the images were still superior to the images reconstructed without motion correction.
  
  
  CONCLUSIONS
  Accelerated tMR images obtained with more than 4 times acceleration can still provide relatively accurate motion fields and yield tMR-based motion corrected PET images with similar image quality as those reconstructed using fully sampled tMR data. The reduction of tMR acquisition time makes it more compatible with routine clinical cardiac PET-MR studies.
authors: Center for Advanced Medical Imaging Sciences, Division of Nuclear Medicine and Molecular Imaging, Department of Imaging, Massachusetts General Hospital, Boston, Massachusetts 02114; Department of Radiology, Harvard Medical School, Boston, Massachusetts 02115; and Departments of Radiology, Psychiatry, Stony Brook Medicine, Stony Brook, New York 11794.
authors: Chuan
authors: C
authors: Huang
authors: Center for Advanced Medical Imaging Sciences, Division of Nuclear Medicine and Molecular Imaging, Department of Imaging, Massachusetts General Hospital, Boston, Massachusetts 02114.
authors: Yoann
authors: Y
authors: Petibon
authors: Center for Advanced Medical Imaging Sciences, Division of Nuclear Medicine and Molecular Imaging, Department of Imaging, Massachusetts General Hospital, Boston, Massachusetts 02114 and Department of Radiology, Harvard Medical School, Boston, Massachusetts 02115.
authors: Jinsong
authors: J
authors: Ouyang
authors: Department of Radiology, Harvard Medical School, Boston, Massachusetts 02115 and Martinos Center for Biomedical Imaging, Charlestown, Massachusetts 02129.
authors: Timothy G
authors: TG
authors: Reese
authors: Radiology and Imaging Sciences, National Institutes of Health Clinical Center, Bethesda, Maryland 20892.
authors: Mark A
authors: MA
authors: Ahlman
authors: Radiology and Imaging Sciences, National Institutes of Health Clinical Center, Bethesda, Maryland 20892.
authors: David A
authors: DA
authors: Bluemke
authors: Center for Advanced Medical Imaging Sciences, Division of Nuclear Medicine and Molecular Imaging, Department of Imaging, Massachusetts General Hospital, Boston, Massachusetts 02114 and Department of Radiology, Harvard Medical School, Boston, Massachusetts 02115.
authors: Georges
authors: G
authors: El Fakhri
mesh_terms: D006321:Heart / Q000000981:diagnostic imaging* / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D009068:Movement; D019047:Phantoms, Imaging; D049268:Positron-Emission Tomography / Q000295:instrumentation*; D013997:Time Factors
references: Magn Reson Med. 2002 Jun;47(6):1202-10
references: 12111967
references: J Magn Reson Imaging. 2012 Jul;36(1):55-72
references: 22696125
references: IEEE Trans Med Imaging. 2008 Aug;27(8):1018-33
references: 18672420
references: Magn Reson Med. 1999 Nov;42(5):952-62
references: 10542355
references: Eur J Nucl Med Mol Imaging. 2010 Mar;37(3):505-16
references: 19789872
references: IEEE J Sel Top Signal Process. 2009 Feb 1;3(1):159-169
references: 21179392
references: Phys Med Biol. 2013 Apr 7;58(7):2085-102
references: 23470288
references: Med Image Anal. 2002 Mar;6(1):29-46
references: 11836133
references: Med Phys. 2014 Apr;41(4):041910
references: 24694141
references: Radiology. 2000 Nov;217(2):564-71
references: 11058661
references: Phys Med Biol. 2005 Jul 7;50(13):2979-89
references: 15972975
references: J Nucl Med. 2009 May;50(5):674-81
references: 19372491
references: Med Phys. 1985 Mar-Apr;12(2):252-5
references: 4000088
references: Med Phys. 2006 May;33(5):1288-98
references: 16752564
references: J Nucl Med. 2013 Mar;54(3):464-71
references: 23287577
references: J Cardiovasc Magn Reson. 2009 Nov 13;11:47
references: 19912654
references: Magn Reson Med. 2007 Dec;58(6):1182-95
references: 17969013
references: Med Phys. 2014 Apr;41(4):042503
references: 24694156
references: Eur Radiol. 2012 Feb;22(2):439-46
references: 21938440
references: IEEE Trans Med Imaging. 2012 Mar;31(3):698-712
references: 22084048
references: Radiology. 1989 Jun;171(3):841-5
references: 2717762
references: J Nucl Med. 2011 Jan;52(1):154-61
references: 21189415
references: Magn Reson Med. 2009 Jan;61(1):103-16
references: 19097216
references: Med Phys. 2011 Jun;38(6):3025-38
references: 21815376
references: Neuroimage. 2014 May 1;91:129-37
references: 24418501
references: Magn Reson Imaging. 1996;14(2):137-50
references: 8847969
references: IEEE Trans Med Imaging. 2008 Aug;27(8):1164-75
references: 18672433
references: Phys Med Biol. 2007 Sep 7;52(17):5187-204
references: 17762080
references: Magn Reson Imaging. 1999 Oct;17(8):1173-81
references: 10499679
references: Circulation. 2003 Jun 17;107(23):2900-7
references: 12771008
references: Magn Reson Med. 2004 Feb;51(2):237-42
references: 14755646
references: Phys Med Biol. 2007 Jun 7;52(11):3201-26
references: 17505098
references: Phys Med Biol. 2006 Aug 7;51(15):3769-83
references: 16861780
references: Clin Nucl Med. 2004 Apr;29(4):243-8
references: 15096971
references: J Nucl Med. 2012 Aug;53(8):1284-91
references: 22743250
references: J Nucl Med. 2004 Jul;45(7):1128-34
references: 15235058