Document Detail


MR blood oxygenation level-dependent signal differences in parenchymal and large draining vessels: implications for functional MR imaging.
MedLine Citation:
PMID:  10588117     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND AND PURPOSE: One major limitation of current functional MR (fMR) imaging is its inability to clarify the relationship between sites of cortical neuronal activation, small parenchymal venules that are in close proximity to these sites, and large draining veins distant from the active parenchyma. We propose to use gradient-echo blood oxygenation level-dependent (BOLD) fMR time courses to differentiate large draining veins from parenchymal microvasculature. METHODS: In eight research subjects, five of whom presented with space-occupying lesions near the central sulcus, gradient-echo fMR imaging was performed during alternating periods of rest and motor activation. MR signal time courses from parenchymal regions and draining veins of different diameters, which were identified using contrast-enhanced T1-weighted scans, were evaluated. Percent signal changes (deltaS) and the time to the onset of MR signal rise (T0) were calculated. RESULTS: Mean delta(S) for all subjects was 2.3% (SD+/-0.7%) for parenchymal activation, 4.3% (SD +1.0%) for sulcal macrovasculature, and 7.3 (SD+/-1.1%) for large superficial bridging veins. The mean time to onset of MR signal increase was 4.4 seconds for parenchymal task-related hemodynamic changes and 6.6 seconds for venous hemodynamic changes, regardless of vessel size. Both the differences in delta(S) and T0 were statistically significant between venous and parenchymal activation (P < .0001). CONCLUSION: Gradient-echo fMR imaging reveals hemodynamic task-related changes regardless of vessel size and therefore might show macrovascular changes distal to the site of neuronal activity. MR-signal time-course characteristics (delta(S) and T0) can be used to differentiate between small parenchymal and larger pial draining vessels, which is especially important in presurgical planning of neurosurgical procedures involving functionally important brain regions. The knowledge about the differences in (delta)S and T0 between micro- and macrovasculature might lead to a more accurate description of the spatial distribution of underlying neuronal activity.
Authors:
T Krings; S G Erberich; F Roessler; J Reul; A Thron
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  AJNR. American journal of neuroradiology     Volume:  20     ISSN:  0195-6108     ISO Abbreviation:  AJNR Am J Neuroradiol     Publication Date:    1999 Nov-Dec
Date Detail:
Created Date:  2000-01-14     Completed Date:  2000-01-14     Revised Date:  2008-02-14    
Medline Journal Info:
Nlm Unique ID:  8003708     Medline TA:  AJNR Am J Neuroradiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1907-14     Citation Subset:  IM    
Affiliation:
Department of Neuroradiology, University Hospital of the Technical University, Aachen, Germany.
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MeSH Terms
Descriptor/Qualifier:
Adult
Aged
Blood Volume / physiology
Brain / blood supply*
Brain Neoplasms / blood supply,  diagnosis
Cerebral Arteries / pathology
Cerebral Veins / pathology
Female
Hemodynamics / physiology
Humans
Image Enhancement*
Magnetic Resonance Imaging*
Male
Microcirculation / pathology
Middle Aged
Oxygen / blood*
Oxygen Consumption / physiology
Regional Blood Flow / physiology
Synaptic Transmission / physiology
Chemical
Reg. No./Substance:
7782-44-7/Oxygen

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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