title: A correction method for streak artifacts in gradient-echo EPI using spin-echo EPI reference data.
abstract: OBJECTIVE
  To analyze the streak artifacts in a gradient-echo echo planar imaging (GE-EPI) sequence and to propose a correction method for the Nyquist ghost artifacts that does not cause streak artifacts in the GE-EPI imaging.
  
  
  METHODS
  Several GE-EPI imaging experiments with various reference scans, using both GE-EPI and SE-EPI scan data, were performed to analyze the streak artifacts and to investigate the spin dephasing phenomena of the GE-EPI reference scan. In addition, the analysis based on the spin dephasing was undertaken in order to demonstrate that the SE-EPI reference data can be used for the correction of the GE-EPI main scan data.
  
  
  RESULTS
  The experimental results confirmed that the improvement of the reference data using either signal averaging or a large flip angle cannot guarantee perfect correction of the streak artifact if the noise is not completely removed. Due to the main field inhomogeneity, the spins of the GE-EPI reference data were dephased in multiple echo signals. The proposed correction method, which uses a SE-EPI reference scan for the GE-EPI images, eliminates the N/2 ghost artifacts without producing streak artifacts.
  
  
  CONCLUSIONS
  It is believed that the proposed phase error correction scheme can improve the EPI performance in high field MRIs with higher magnetic field inhomogeneities.
authors.affiliation: Neuroscience Research Institute, Gachon University of Medicine and Science, Incheon, Republic of Korea.
authors.forename: Jun-Young
authors.initials: JY
authors.lastname: Chung
authors.forename: Yeji
authors.initials: Y
authors.lastname: Han
authors.forename: Zang-Hee
authors.initials: ZH
authors.lastname: Cho
authors.forename: Hyunwook
authors.initials: H
authors.lastname: Park
mesh_terms: D000465:Algorithms; D016477:Artifacts; D017352:Echo-Planar Imaging / Q000379:methods* / Q000592:standards; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013382:Subtraction Technique
references.citation: J Magn Reson Imaging. 1999 Jun;9(6):847-52
references.pmid: 10373034
references.citation: Magn Reson Med. 2002 Feb;47(2):337-43
references.pmid: 11810678
references.citation: Magn Reson Med. 2004 Mar;51(3):621-4
references.pmid: 15004807
references.citation: Magn Reson Med. 2007 Apr;57(4):731-41
references.pmid: 17390358
references.citation: Magn Reson Med. 1992 Feb;23(2):311-23
references.pmid: 1549045
references.citation: Magn Reson Med. 1997 Jul;38(1):89-100
references.pmid: 9211384
references.citation: Magn Reson Med. 1999 Sep;42(3):541-7
references.pmid: 10467298
references.citation: J Magn Reson Imaging. 2006 Sep;24(3):683-9
references.pmid: 16892198
references.citation: Magn Reson Med. 2001 Jan;45(1):96-108
references.pmid: 11146491
references.citation: Magn Reson Med. 2010 Dec;64(6):1800-13
references.pmid: 20806354
references.citation: Magn Reson Med. 1996 Jul;36(1):166-71
references.pmid: 8795036
references.citation: Magn Reson Med. 2002 Apr;47(4):812-7
references.pmid: 11948745
references.citation: Magn Reson Med. 2010 Dec;64(6):1781-91
references.pmid: 20665898
references.citation: Magn Reson Med. 1997 Oct;38(4):615-27
references.pmid: 9324329
references.citation: Neuroimage. 2006 Jun;31(2):609-22
references.pmid: 16480898
references.citation: Magn Reson Imaging. 1988 Sep-Oct;6(5):585-90
references.pmid: 3226241
references.citation: Magn Reson Med. 1999 Aug;42(2):290-9
references.pmid: 10440954
references.citation: Magn Reson Med. 1995 Jul;34(1):65-73
references.pmid: 7674900
references.citation: Magn Reson Med. 1991 Aug;20(2):268-84
references.pmid: 1775052
references.citation: Magn Reson Med. 2004 Jun;51(6):1247-53
references.pmid: 15170846
references.citation: Magn Reson Med. 1998 Apr;39(4):596-605
references.pmid: 9543422
references.citation: Magn Reson Med. 1998 Feb;39(2):328-30
references.pmid: 9469719
references.citation: Magn Reson Med. 2001 Aug;46(2):407-11
references.pmid: 11477647