| Balanced SSFP transient imaging using variable flip angles for a predefined signal profile. | |
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MedLine Citation:
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PMID: 20632411 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Variable flip angles are used in steady-state free precession (SSFP) acquisitions (e.g., time-of-flight) but to a lesser extent than in spin echo acquisitions. In balanced steady-state free precession, imaging is often assumed to occur during the steady state, which has been well described in the literature. However, in many cases, imaging occurs during the transient stage, and the use of variable flip angles can improve signal and thus image quality. Here, we present the calculation of flip angles in transient balanced steady-state free precession to generate a predefined signal profile. The signal profile was iteratively optimized to maximize the integral of the signal versus time curve. The key contribution of this work is the formulation of the flip angle as a deterministic function of the preceding and desired magnetization. Catalyzation schemes, e.g., Kaiser-windowed ramp, can be combined with variable flip angles balanced steady-state free precession to reduce signal oscillations. A uniform signal profile was used as an example to demonstrate the variable flip angle algorithm. Accuracy of the algorithm and Bloch simulations were verified with MRI phantom acquisitions. Renal angiograms were acquired using an inflow-based balanced steady-state free precession MR angiography technique; improved small-vessel depiction was observed in volunteer examinations. |
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Authors:
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Pauline W Worters; Brian A Hargreaves |
Publication Detail:
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Type: Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Magnetic resonance in medicine : official journal of the Society of Magnetic Resonance in Medicine / Society of Magnetic Resonance in Medicine Volume: 64 ISSN: 1522-2594 ISO Abbreviation: Magn Reson Med Publication Date: 2010 Nov |
Date Detail:
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Created Date: 2010-10-28 Completed Date: 2011-03-08 Revised Date: 2011-11-01 |
Medline Journal Info:
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Nlm Unique ID: 8505245 Medline TA: Magn Reson Med Country: United States |
Other Details:
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Languages: eng Pagination: 1404-12 Citation Subset: IM |
Copyright Information:
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Copyright © 2010 Wiley-Liss, Inc. |
Affiliation:
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Department of Radiology, Stanford University, Stanford, California, USA. worters@stanford.edu |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Algorithms* Humans Image Enhancement / methods* Image Interpretation, Computer-Assisted / methods* Magnetic Resonance Angiography / instrumentation, methods* Phantoms, Imaging Reproducibility of Results Sensitivity and Specificity |
| Grant Support | |
ID/Acronym/Agency:
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P41 RR009784-11/RR/NCRR NIH HHS; R01 EB009055-01/EB/NIBIB NIH HHS; R01 EB009055-01/EB/NIBIB NIH HHS |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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