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Are TrueFISP images T 2 / T 1 ‐weighted?
Author(s) -
Huang TengYi,
Huang IngJye,
Chen ChengYu,
Scheffler Klaus,
Chung HsiaoWen,
Cheng HuiCheng
Publication year - 2002
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.10260
Subject(s) - weighting , contrast (vision) , image contrast , nuclear magnetic resonance , flip angle , physics , proton , resolution (logic) , precession , computer science , optics , magnetic resonance imaging , artificial intelligence , medicine , radiology , astronomy , acoustics , quantum mechanics
Abstract Images acquired using the TrueFISP technique (true fast imaging with steady‐state precession) are generally believed to exhibit T 2 / T 1 ‐weighting. In this study, it is demonstrated that with the widely used half‐flip‐angle preparation scheme, approaching the steady state requires a time length comparable to the scan time such that the transient‐state response may dominate the TrueFISP image contrast. Two‐dimensional images of the human brain were obtained using various phase‐encoding matrices to investigate the transient‐state signal behavior. Contrast between gray and white matter was found to change significantly from proton‐density‐ to T 2 / T 1 ‐weighted as the phase‐encoding matrix size increased, which was in good agreement with theoretical predictions. It is concluded that TrueFISP images in general exhibit T 2 / T 1 ‐contrast, but should be more appropriately regarded as exhibiting a transient‐state combination of proton‐density and T 2 / T 1 contrast under particular imaging conditions. Interpretation of tissue characteristics from TrueFISP images in clinical practice thus needs to be exercised with caution. Magn Reson Med 48:684–688, 2002. © 2002 Wiley‐Liss, Inc.