2024-03-28T18:55:55Z
http://eprints.drcmr.dk/cgi/oai2
oai:www.drcmr.dk:19
2010-04-02T00:05:23Z
7374617475733D707562
7375626A656374733D473036:47303678353335
7375626A656374733D453035:45303578313936:4530357831393678383637:453035783139367838363778353139
7375626A656374733D453031:45303178333730:4530317833373078333530:453031783337307833353078383235:45303178333730783335307838323578353030:4530317833373078333530783832357835303078323030
74797065733D61727469636C65
http://eprints.drcmr.dk/19/
Reconstruction strategy for echo planar spectroscopy and its application to partially undersampled imaging.
Hanson, L G
Schaumburg, K
Paulson, O B
Metabolism
Magnetic Resonance Spectroscopy
Echo-Planar Imaging
The most commonly encountered form of echo planar spectroscopy involves oscillating gradients in one spatial dimension during readout. Data are consequently not sampled on a Cartesian grid. A fast gridding algorithm applicable to this particular situation is presented. The method is optimal, i.e., it performs as well as the full discrete Fourier transform for band limited signals while allowing for use of the fast Fourier transform. The method is demonstrated for reconstruction of data that are partially undersampled in the time domain. The advantages of undersampling are lower hardware requirements or fewer interleaves per acquisition. The method is of particular interest when large bandwidths are needed (e.g., for high field scanning) and for scanners with limited gradient performance. The unavoidable artifacts resulting from undersampling are demonstrated to be acceptable for spectroscopy with long echo times.
Wiley InterScience
2000
Article
PeerReviewed
application/pdf
http://eprints.drcmr.dk/19/1/article.pdf
http://dx.doi.org/10.1002/1522-2594(200009)44:3%3C412::AID-MRM11%3E3.0.CO;2-P
Hanson, L G and Schaumburg, K and Paulson, O B (2000) Reconstruction strategy for echo planar spectroscopy and its application to partially undersampled imaging. Magnetic Resonance in Medicine, 44 (3). pp. 412-7. ISSN 0740-3194
http://eprints.drcmr.dk/19/http://eprints.drcmr.dk/19/1/
oai:www.drcmr.dk:20
2010-04-02T00:05:24Z
7374617475733D707562
7375626A656374733D453031:45303178333730:4530317833373078333530:453031783337307833353078353030
7375626A656374733D473036:47303678353335
7375626A656374733D453035:45303578313936:4530357831393678383637:453035783139367838363778353139
74797065733D61727469636C65
http://eprints.drcmr.dk/20/
Optimal voxel size for measuring global gray and white matter proton metabolite concentrations using chemical shift imaging.
Hanson, L G
Adalsteinsson, E
Pfefferbaum, A
Spielman, D M
Metabolism
Magnetic Resonance Imaging
Magnetic Resonance Spectroscopy
Quantification of gray and white matter levels of spectroscopically visible metabolites can provide important insights into brain development and pathological conditions. Chemical shift imaging offers a gain in efficiency for estimation of global gray and white matter metabolite concentrations compared to single voxel methods. In the present study, the optimal voxel size is calculated from segmented human brain data and accompanying field maps. The optimal voxel size is found to be approximately 8 cc, but a wide range of values, 4-64 cc, can be chosen with little increase in estimated concentration error (<15%). Magn Reson Med 44:10-18, 2000.
Wiley InterScience
2000
Article
PeerReviewed
application/pdf
http://eprints.drcmr.dk/20/1/article3.pdf
http://dx.doi.org/10.1002/1522-2594(200007)44:1%3C10::AID-MRM3%3E3.0.CO;2-8
Hanson, L G and Adalsteinsson, E and Pfefferbaum, A and Spielman, D M (2000) Optimal voxel size for measuring global gray and white matter proton metabolite concentrations using chemical shift imaging. Magnetic Resonance in Medicine: MRM, 44 (1). pp. 10-8. ISSN 0740-3194
http://eprints.drcmr.dk/20/http://eprints.drcmr.dk/20/1/