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Signal targeting with alternating radiofrequency (STAR) sequences: Application to MR angiography
Author(s) -
Edelman Robert R.,
Siewert Bettina,
Adamis Mary,
Gaa Jochen,
Laub Gerhard,
Wielopolski Piotr
Publication year - 1994
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.1910310219
Subject(s) - circle of willis , signal (programming language) , subtraction , magnetic resonance angiography , angiography , carotid bifurcation , intensity (physics) , nuclear magnetic resonance , contrast (vision) , physics , computer science , magnetic resonance imaging , radiology , medicine , optics , mathematics , arithmetic , stenosis , programming language
Abstract We describe a time of flight subtraction method for cine MR angiography that provides nearly perfect suppression of background signal intensity with excellent flow contrast. The method consists of a preparation phase, during which the longitudinal magnetization of the target tissue is inverted on alternate acquisitions and the background tissue is presaturated, followed by a readout phase using a cine segmented turboFLASH sequence with a shared echo modification to improve temporal resolution. With appropriate alternation of the phases of the radiofrequency excitation pulses, there is cancellation of the background signal intensity but flow signal is optimized. By using a thick section (up to 25 mm), substantial portions of the vascular territory are encompassed in a single plane. This permits rapid, dynamic assessment of flow patterns in areas such as the circle of Willis, carotid bifurcation, or renal arteries. Applications of the method for bright and dark blood cine MR angiography are demonstrated.