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Two‐dimensional radial acquisition technique with density adaption in sodium MRI
Author(s) -
Konstandin Simon,
Nagel Armin M.,
Heiler Patrick M.,
Schad Lothar R.
Publication year - 2011
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.22684
Subject(s) - sampling (signal processing) , slew rate , trajectory , noise (video) , signal (programming language) , projection (relational algebra) , signal to noise ratio (imaging) , relaxation (psychology) , computer science , physics , nuclear magnetic resonance , optics , algorithm , artificial intelligence , detector , psychology , social psychology , image (mathematics) , programming language , quantum mechanics , voltage , astronomy
Conventional 2D radial projections suffer from losses in signal‐to‐noise ratio efficiency because of the nonuniform k ‐space sampling. In this study, a 2D projection reconstruction method with variable gradient amplitudes is presented to cover the k ‐space uniformly. The gradient is designed to keep the average sampling density constant. By this, signal‐to‐noise ratio is increased, and the linear form of the radial trajectory is kept. The simple gradient design and low hardware requirements in respect of slew rate allow an easy implementation at MR scanners. Measurements with the density‐adapted 2D radial trajectory were compared with the conventional projection reconstruction method. It is demonstrated that the density‐adapted 2D radial trajectory technique provides higher signal‐to‐noise ratio (up to 28% in brain tissue), less blurring, and fewer artifacts in the presence of magnetic field inhomogeneities than imaging with the conventional 2D radial trajectory scheme. The presented sequence is well‐suited for electrocardiographically gated sodium heart MRI and other applications with short relaxation times. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.