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Artifacts and signal loss due to flow in the presence of B o inhomogeneity
Author(s) -
Drangova Maria,
Pelc Norbert J.
Publication year - 1996
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.1910350116
Subject(s) - ghosting , pulsatile flow , signal (programming language) , nuclear magnetic resonance , flip angle , flow (mathematics) , materials science , in vivo , magnetic resonance imaging , intensity (physics) , imaging phantom , physics , optics , biomedical engineering , mechanics , computer science , medicine , radiology , microbiology and biotechnology , biology , cardiology , programming language
An in vitro study was performed to investigate the effects of B o inhomogeneity on magnetic resonance images of flow. Controlled inhomogeneity gradients (G 1 ) were applied and the magnitude of the artifacts produced was quantified for different echo delay times ( TE ). Both steady and pulsatile flows were examined. In the presence of an inhomogeneity gradient, signal loss is apparent if the flow is pulsatile and/or if the slice thickness is large. The signal loss increases with increasing TE and G 1 . With pulsatile flow, ghosting artifacts are also generated. These increase in intensity with increasing TE and G 1 . In vivo , field inhomogeneity due to susceptibility variations is large enough to produce these effects. Representative time‐of‐flight images obtained of a normal volunteer with two different TEs demonstrate the effect in vivo . Flow‐related signal loss and artifacts, therefore, increase with increasing TE independent of the moments of the applied gradients.