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MR angiography using spin‐lock flow tagging
Author(s) -
Azhari Haim,
McKenzie Charles A.,
Edelman Robert R.
Publication year - 2001
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.1295
Subject(s) - spins , pulse sequence , nuclear magnetic resonance , pulse (music) , scanner , physics , contrast (vision) , sequence (biology) , subtraction , arterial spin labeling , signal (programming language) , spin echo , blood flow , materials science , optics , magnetic resonance imaging , chemistry , computer science , mathematics , medicine , radiology , biochemistry , arithmetic , detector , programming language , condensed matter physics
A method for MR angiography using an RF labeling technique is suggested. The method utilizes a slice‐selective spin‐lock pulse sequence for tagging the spins of inflowing blood. The pulse sequence begins with a spatially selective 90° x RF pulse, followed by a nonselective composite locking pulse of 135° y − n[360° y ]‐135° y and by a 90° ‐x pulse. A spoiler gradient is then applied. A rapid imaging stage, which yields a T 1 ρ‐weighted signal from the tagged spins, completes the sequence. Untagged spins are thoroughly dephased and consequently suppressed in the image. Thus, contrast is obtained without an injection of a contrast material or image subtraction. Furthermore, the flow of the tagged bolus can be visualized. The sequence was implemented on phantoms and on human volunteers using a 1.5T scanner. The results indicate the feasibility of the suggested sequence. Magn Reson Med 46:1041–1044, 2001. © 2001 Wiley‐Liss, Inc.