Abstract:
:Respiratory and other regular motions during two-dimensional Fourier transform magnetic resonance imaging produce image artifacts consisting of local blurring and more or less regularly spaced "ghost" images propagating along the direction of the phase-encoding magnetic field gradient. The patterns of these ghost artifacts can be understood in terms of the technique of image production and basic properties of the discrete Fourier transform. This understanding permits, without respiratory gating, production of images of improved quality in body regions in which there is significant respiratory motion. In particular, the ghosts can be maximally separated from the primary image by choosing intervals between phase-encoding gradient pulse increments that are equal to one-half the respiratory period; they can be minimally separated by choosing an interval equal to the respiratory period. Increasing the number of signal averages between each phase-encoding increment decreases the intensity of the ghosts.
journal_name
Radiologyjournal_title
Radiologyauthors
Axel L,Summers RM,Kressel HY,Charles Cdoi
10.1148/radiology.160.3.3737920subject
Has Abstractpub_date
1986-09-01 00:00:00pages
795-801issue
3eissn
0033-8419issn
1527-1315journal_volume
160pub_type
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