| Hypercapnia-induced effects on image contrast based on intermolecular double-quantum coherences. | |
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MedLine Citation:
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PMID: 19030164 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Intermolecular double-quantum coherences (iDQCs) are well known to be sensitive to magnetic-field perturbations inside tissues. However, the exact relation between iDQC contrast in magnetic resonance imaging (MRI) and the underlying physiology is less well understood. To investigate parameters that influence iDQC signal changes observed during neuronal activation, carbogen-inhalation experiments were performed to produce a pure hemodynamic response without affecting oxidative metabolism. Eight human volunteers were studied at 2.9 T using gradient-recalled echo (GRE) and spin-echo (SE) variants of a single-shot sequence selecting iDQCs. Results were compared with conventional recordings of the blood oxygen level-dependent (BOLD) effect. Maps of voxels responding to the carbogen challenge showed similar distributions for iDQC and conventional MRI after adjustment for different sensitivities. Strong diffusion weighting of iDQC sequences and transverse relaxation effects suggested quantitative suppression of intravascular signal contributions. A particular susceptibility to local gradients during the evolution period (in which iDQCs evolve at twice the Larmor frequency) plus a strong relaxation weighting during the detection period due to the use of a long echo time (for refocusing of the dipolar signal) produced iDQC signal changes up to 21.7% +/- 2.5%. These results agreed quantitatively with computations based on the balloon model of BOLD-weighted MRI without requiring further assumptions. |
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Authors:
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Andreas Schäfer; Stefan Zysset; Wolfgang Heinke; Harald E Möller |
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Publication Detail:
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Type: Journal Article |
Journal Detail:
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Title: Magnetic resonance in medicine : official journal of the Society of Magnetic Resonance in Medicine / Society of Magnetic Resonance in Medicine Volume: 60 ISSN: 1522-2594 ISO Abbreviation: Magn Reson Med Publication Date: 2008 Dec |
Date Detail:
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Created Date: 2008-12-01 Completed Date: 2009-02-27 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 8505245 Medline TA: Magn Reson Med Country: United States |
Other Details:
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Languages: eng Pagination: 1306-12 Citation Subset: IM |
Copyright Information:
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(c) 2008 Wiley-Liss, Inc. |
Affiliation:
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Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Adult Algorithms* Brain / pathology* Brain Ischemia / pathology* Female Humans Hypercapnia / complications, pathology* Image Enhancement / methods Image Interpretation, Computer-Assisted / methods* Magnetic Resonance Imaging / methods* Male Reproducibility of Results Sensitivity and Specificity |
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