title: Localized high-resolution DTI of the human midbrain using single-shot EPI, parallel imaging, and outer-volume suppression at 7T.
abstract: Localized high-resolution diffusion tensor images (DTI) from the midbrain were obtained using reduced field-of-view (rFOV) methods combined with SENSE parallel imaging and single-shot echo planar (EPI) acquisitions at 7T. This combination aimed to diminish sensitivities of DTI to motion, susceptibility variations, and EPI artifacts at ultra-high field. Outer-volume suppression (OVS) was applied in DTI acquisitions at 2- and 1-mm(2) resolutions, b=1000s/mm(2), and six diffusion directions, resulting in scans of 7- and 14-min durations. Mean apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values were measured in various fiber tract locations at the two resolutions and compared. Geometric distortion and signal-to-noise ratio (SNR) were additionally measured and compared for reduced-FOV and full-FOV DTI scans. Up to an eight-fold data reduction was achieved using DTI-OVS with SENSE at 1mm(2), and geometric distortion was halved. The localization of fiber tracts was improved, enabling targeted FA and ADC measurements. Significant differences in diffusion properties were observed between resolutions for a number of regions suggesting that FA values are impacted by partial volume effects even at a 2-mm(2) resolution. The combined SENSE DTI-OVS approach allows large reductions in DTI data acquisition and provides improved quality for high-resolution diffusion studies of the human brain.
authors.affiliation: Institute of Imaging Science, Vanderbilt University, 1161 21st Ave. South, MCN AA-1105, Nashville, TN 37232-2310, USA. chris.wargo@vanderbilt.edu
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Wargo
authors.forename: John C
authors.initials: JC
authors.lastname: Gore
mesh_terms: D000328:Adult; D000465:Algorithms; D001921:Brain / Q000166:cytology*; D056324:Diffusion Tensor Imaging / Q000379:methods*; D017352:Echo-Planar Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D008636:Mesencephalon; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods*; D009413:Nerve Fibers, Myelinated / Q000648:ultrastructure*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013382:Subtraction Technique
references.citation: J Magn Reson Imaging. 2009 Apr;29(4):987-93
references.pmid: 19306448
references.citation: Magn Reson Med. 2002 Jun;47(6):1202-10
references.pmid: 12111967
references.citation: Neuroimage. 2002 Sep;17(1):272-86
references.pmid: 12482083
references.citation: Magn Reson Imaging. 2008 Jul;26(6):790-800
references.pmid: 18499378
references.citation: MAGMA. 2008 Mar;21(1-2):73-86
references.pmid: 17973132
references.citation: Magn Reson Imaging. 2013 Jul;31(6):810-9
references.pmid: 23541390
references.citation: Magn Reson Med. 2005 Dec;54(6):1575-9
references.pmid: 16254946
references.citation: AJNR Am J Neuroradiol. 2010 Nov;31(10):1879-85
references.pmid: 20595371
references.citation: Magn Reson Imaging. 2012 May;30(4):496-505
references.pmid: 22285880
references.citation: Radiology. 1996 Dec;201(3):637-48
references.pmid: 8939209
references.citation: J Magn Reson Imaging. 2009 Feb;29(2):454-60
references.pmid: 19161202
references.citation: Magn Reson Med. 2007 Mar;57(3):625-30
references.pmid: 17326167
references.citation: Neuroimaging Clin N Am. 2006 May;16(2):299-309, xi
references.pmid: 16731368
references.citation: Magn Reson Med. 2006 Feb;55(2):335-42
references.pmid: 16416432
references.citation: J Magn Reson. 2004 Jan;166(1):111-22
references.pmid: 14675826
references.citation: Magn Reson Imaging. 2011 Jul;29(6):739-51
references.pmid: 21571473
references.citation: Magn Reson Med. 2008 Aug;60(2):468-73
references.pmid: 18666126
references.citation: Neuroimage. 2008 Mar 1;40(1):53-8
references.pmid: 18187344
references.citation: Neuroimage. 2012 Apr 2;60(2):967-78
references.pmid: 22245337
references.citation: Magn Reson Med. 2013 Mar 1;69(3):793-802
references.pmid: 22592941
references.citation: Magn Reson Imaging. 2004 Jul;22(6):751-9
references.pmid: 15234443
references.citation: Magn Reson Med. 2004 Feb;51(2):230-6
references.pmid: 14755645
references.citation: Annu Int Conf IEEE Eng Med Biol Soc. 2008;2008:5761-4
references.pmid: 19164026
references.citation: Magn Reson Med. 1994 Jan;31(1):67-72
references.pmid: 8121272
references.citation: Magn Reson Imaging. 1994;12(3):455-60
references.pmid: 8007775
references.citation: Magn Reson Med. 2001 Jul;46(1):24-30
references.pmid: 11443707
references.citation: Magn Reson Med. 1994 Oct;32(4):535-9
references.pmid: 7997122
references.citation: J Magn Reson B. 1996 Jun;111(3):209-19
references.pmid: 8661285
references.citation: Magn Reson Med. 1999 Nov;42(5):952-62
references.pmid: 10542355
references.citation: Magn Reson Med. 2010 Jul;64(1):9-14
references.pmid: 20577977
references.citation: IEEE Trans Med Imaging. 2003 Nov;22(11):1470-9
references.pmid: 14606680
references.citation: J Magn Reson Imaging. 1998 Sep-Oct;8(5):1022-32
references.pmid: 9786138
references.citation: Radiology. 1985 Sep;156(3):743-7
references.pmid: 4023236
references.citation: J Magn Reson. 2007 Jun;186(2):167-75
references.pmid: 17331765
references.citation: Magn Reson Med. 2004 Apr;51(4):853-7
references.pmid: 15065261
references.citation: Magn Reson Med. 1990 Apr;14(1):123-39
references.pmid: 2352469
references.citation: Z Med Phys. 2011 Sep;21(3):216-27
references.pmid: 21239149
references.citation: AJNR Am J Neuroradiol. 2007 Jun-Jul;28(6):1102-6
references.pmid: 17569968
references.citation: J Magn Reson Imaging. 2011 Jun;33(6):1456-63
references.pmid: 21591016
references.citation: Magn Reson Med. 2002 Jul;48(1):128-36
references.pmid: 12111940
references.citation: Magn Reson Med. 2006 Aug;56(2):446-51
references.pmid: 16791864
references.citation: Magn Reson Imaging. 2010 Dec;28(10):1541-5
references.pmid: 20850242
references.citation: Magn Reson Med. 2002 Jan;47(1):42-52
references.pmid: 11754441