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Conventional and fast spin‐echo MR imaging: Minimizing echo time
Author(s) -
Vinitski Simon,
Mitchell Donald G.,
Einstein Steven G.,
Rao Vijay M.,
Flanders Adam E.,
Schweitzer Mark E.,
Listerud John,
Schnall Mitchell D.
Publication year - 1993
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.1880030312
Subject(s) - magnetic resonance imaging , artifact (error) , echo time , echo (communications protocol) , nuclear medicine , spin echo , nuclear magnetic resonance , k space , medicine , fast spin echo , physics , radiology , computer science , computer vision , computer network
Abstract Magnetic resonance imaging is frequently complicated by the presence of motion and susceptibility gradients. Also, some biologic tissues have short T2s. These problems are particularly troublesome in fast spin‐echo (FSE) imaging, in which T2 decay and motion between echoes result in image blurring and ghost artifacts. The authors reduced TE in conventional spin‐echo (SE) imaging to 5 msec and echo spacing (E‐space) in FSE imaging to 6 msec. All magnetic gradients (except readout) were kept at a maximum, with data sampling as fast as 125 kHz and only ramp waveforms used. Truncated sine radio‐frequency pulses and asymmetric echo sampling were also used in SE imaging. Short TE (5.8 msec) SE images of the upper abdomen were compared with conventional SE images (TE =11 msec). Also, FSE images with short E‐space were compared with conventional FSE images in multiple body sites. Short TE significantly improved the liver‐spleen contrast‐to‐total noise ratio (C/N) (7.9 vs 4.1, n = 9, P <.01) on T1‐weighted SE images, reduced the intensity of ghost artifacts (by 34%, P <.02), and increased the number of available imaging planes by 30%. It also improved delineation of cranial nerves and reduced susceptibility artifacts. On short E‐space FSE images, spine, lung, upper abdomen, and musculoskeletal tissues appeared crisper and measured spleen‐liver C/N increased significantly (6.9 vs 4.0, n = 12, P <.01). The delineation of tissues with short T2 (eg, cartilage) and motion artifact suppression were also improved. Short TE methods can improve image quality in both SE and FSE imaging and merit further clinical evaluation.