GLORIA

GEOMAR Library Ocean Research Information Access

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Type of Medium: Book
    Series Statement: FAO fisheries circular 781
    Language: English
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 2
    Publication Date: 2016-10-23
    Description: Purpose Balanced steady-state free precession (bSSFP) sequences can provide superior signal-to-noise ratio efficiency for hyperpolarized (HP) carbon-13 ( 13 C) magnetic resonance imaging by efficiently utilizing the nonrecoverable magnetization, but managing their spectral response is challenging in the context of metabolic imaging. A new spectrally selective bSSFP sequence was developed for fast imaging of multiple HP 13 C metabolites with high spatiotemporal resolution. Theory and Methods This novel approach for bSSFP spectral selectivity incorporates optimized short-duration spectrally selective radiofrequency pulses within a bSSFP pulse train and a carefully chosen repetition time to avoid banding artifacts. Results The sequence enabled subsecond 3D dynamic spectrally selective imaging of 13 C metabolites of copolarized [1- 13 C]pyruvate and [ 13 C]urea at 2-mm isotropic resolution, with excellent spectral selectivity (∼100:1). The sequence was successfully tested in phantom studies and in vivo studies with normal mice. Conclusion This sequence is expected to benefit applications requiring dynamic volumetric imaging of metabolically active 13 C compounds at high spatiotemporal resolution, including preclinical studies at high field and, potentially, clinical studies.Magn Reson Med, 2016. © 2016 International Society for Magnetic Resonance in Medicine.
    Print ISSN: 0740-3194
    Electronic ISSN: 1522-2594
    Topics: Medicine
    Published by Wiley-Blackwell
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 3
    Publication Date: 2013-11-19
    Description: Purpose A calibrationless parallel imaging reconstruction method, termed simultaneous autocalibrating and k-space estimation (SAKE), is presented. It is a data-driven, coil-by-coil reconstruction method that does not require a separate calibration step for estimating coil sensitivity information. Methods In SAKE, an undersampled, multichannel dataset is structured into a single data matrix. The reconstruction is then formulated as a structured low-rank matrix completion problem. An iterative solution that implements a projection-onto-sets algorithm with singular value thresholding is described. Results Reconstruction results are demonstrated for retrospectively and prospectively undersampled, multichannel Cartesian data having no calibration signals. Additionally, non-Cartesian data reconstruction is presented. Finally, improved image quality is demonstrated by combining SAKE with wavelet-based compressed sensing. Conclusion Because estimation of coil sensitivity information is not needed, the proposed method could potentially benefit MR applications where acquiring accurate calibration data is limiting or not possible at all. Magn Reson Med, 2013. © 2013 Wiley Periodicals, Inc.
    Print ISSN: 0740-3194
    Electronic ISSN: 1522-2594
    Topics: Medicine
    Published by Wiley-Blackwell
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 4
    Publication Date: 2013-02-13
    Description: Purpose: The purpose of this work is to design an improved Slice-selective Tunable-flip AdiaBatic Low peak-power Excitation (STABLE) pulse with shorter duration and increased off-resonance immunity to make it suitable for use in a greater range of applications and at higher field strengths. An additional aim is to design a variant of this pulse to achieve B 1 -insensitive, fat-suppressed excitation. Methods: The adiabatic SLR algorithm was used to generate a more uniform spectral pulse envelope for this improved radiofrequency pulse for adiabatic slice-selective excitation, called STABLE-2. Pulse parameters were adjusted to design a version of STABLE-2 with a spectral null centered on lipids. Results: In vivo images obtained of the human brain at 3 and 7 T demonstrate that STABLE-2 provides robust, uniform, slice-selective excitation over a range of B 1 values. Phantom and in vivo knee images obtained at 3 T demonstrate the effectiveness of STABLE-2 for fat suppression. Conclusions: STABLE-2 achieves B 1 -insensitive slice-selective excitation while providing greater off-resonance immunity and a shorter pulse duration, when compared to the original STABLE pulse. In particular, the 9.8-ms STABLE-2 pulse provides slice selectivity over 120 Hz whereas the 21-ms STABLE pulse is limited to 80 Hz off-resonance. B 1 -Insensitive fat-suppressed excitation may also be achieved by using a variant of this pulse. Magn Reson Med, 2013. © 2013 Wiley Periodicals, Inc.
    Print ISSN: 0740-3194
    Electronic ISSN: 1522-2594
    Topics: Medicine
    Published by Wiley-Blackwell
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...