Abstract:
:This paper describes the development of a novel technique for functional MRI of the human brain at 0.135 microL resolution for a whole brain section. In comparison with conventional studies at 3 mm isotropic resolution or 27 microL voxel size, the method yields an improvement by a factor of 200. To achieve optimum image quality, the approach is based on a multi-echo fast low-angle shot (FLASH) sequence with unipolar traversals of k-space in the frequency-encoding dimension and echo train shifting to avoid amplitude discontinuities in the phase-encoding dimension. These strategies ensure a smooth point-spread function and eliminate image ghosting artifacts without the need for any phase correction or other post-processing. Signal-to-noise losses due to the considerably reduced voxel sizes are compensated for by single slice acquisitions, optimized bandwidths and an experimental four-channel shoulder coil matched to the posterior portion of the head. Multi-echo FLASH studies of the human brain (2.9 T, seven echoes, 200 Hz/pixel bandwidth, effective echo time 36 ms, acquisition time 6 s) at 300 microm resolution (no interpolation) and 1.5 mm slice thickness revealed robust activations in primary visual areas in response to binocular stimulation. The new method holds promise for refined studies of the columnar organization of specific brain systems and for functional assessments of the gray matter at laminar resolution.
journal_name
NMR Biomedjournal_title
NMR in biomedicineauthors
Voit D,Frahm Jdoi
10.1002/nbm.998subject
Has Abstractpub_date
2005-12-01 00:00:00pages
481-8issue
8eissn
0952-3480issn
1099-1492journal_volume
18pub_type
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journal_title:NMR in biomedicine
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更新日期:1998-04-01 00:00:00
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更新日期:2012-01-01 00:00:00
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journal_title:NMR in biomedicine
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更新日期:2010-10-01 00:00:00
abstract::Evaluation of high intensity focused ultrasound (HIFU) treatment with MRI is generally based on assessment of the non-perfused volume from contrast-enhanced T1-weighted images. However, the vascular status of tissue surrounding the non-perfused volume has not been extensively investigated with MRI. In this study, clus...
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journal_title:NMR in biomedicine
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