Sodium MRI using a density-adapted 3D radial acquisition technique.

Autor: Nagel, Armin M., Laun, Frederik B., Weber, Marc-André, Matthies, Christian, Semmler, Wolfhard, Schad, Lothar R.
Zdroj: Magnetic Resonance in Medicine; Dec2009, Vol. 62 Issue 6, p1565-1573, 9p
Abstrakt: A density-adapted three-dimensional radial projection reconstruction pulse sequence is presented which provides a more efficient k-space sampling than conventional three-dimensional projection reconstruction sequences. The gradients of the density-adapted three-dimensional radial projection reconstruction pulse sequence are designed such that the averaged sampling density in each spherical shell of k-space is constant. Due to hardware restrictions, an inner sphere of k-space is sampled without density adaption. This approach benefits from both the straightforward handling of conventional three-dimensional projection reconstruction sequence trajectories and an enhanced signal-to-noise ratio (SNR) efficiency akin to the commonly used three-dimensional twisted projection imaging trajectories. Benefits for low SNR applications, when compared to conventional three-dimensional projection reconstruction sequences, are demonstrated with the example of sodium imaging. In simulations of the point-spread function, the SNR of small objects is increased by a factor 1.66 for the density-adapted three-dimensional radial projection reconstruction pulse sequence sequence. Using analytical and experimental phantoms, it is shown that the density-adapted three-dimensional radial projection reconstruction pulse sequence allows higher resolutions and is more robust in the presence of field inhomogeneities. High-quality in vivo images of the healthy human leg muscle and the healthy human brain are acquired. For equivalent scan times, the SNR is up to a factor of 1.8 higher and anatomic details are better resolved using density-adapted three-dimensional radial projection reconstruction pulse sequence. Magn Reson Med, 2009. © 2009 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
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