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Dynamic spin‐echo imaging: Theoretical assessment and implementation
Author(s) -
Bishop Jonathan,
Henkelman R. Mark,
Plewes Donald B.
Publication year - 1994
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.1880040617
Subject(s) - echo (communications protocol) , fast spin echo , computer science , nuclear magnetic resonance , magnetic resonance imaging , medicine , radiology , physics , computer security
A spin‐echo method for obtaining dynamic magnetic resonance (MR) images is described. The method combines the RARE (rapid acquisition with relaxation enhancement) pulse sequence with a data acquisition scheme in which only a centric fraction of the raw data is sampled to increase the time resolution of the dynamic images. The missing high‐resolution data are supplied from reference images. By these means, an effective time resolution of about 10 seconds per image is achieved, which is suitable for diagnostic assessment of contrast enhancement procedures. A promising clinical application is contrast‐enhanced MR imaging of the pituitary. Although the resolution of small objects in this size range is potentially degraded, this shortcoming is compensated for with use of variable refocusing flip angles. In the context of pituitary imaging, the centric 30%–40% of the raw data is shown to be the optimal fraction to acquire for the low‐resolution dynamic images. Ten patients with previous history of pituitary disease have been imaged with dynamic and conventional spin‐echo techniques. In six of these patients, an equivalent diagnosis was reached with dynamic and conventional images, while in two, only the dynamic images showed the lesion; in the final two patients, only the conventional images showed the lesion.