Linked Life Data

3782539

Source:http://linkedlifedata.com/resource/pubmed/id/3782539

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
1987-1-9
pubmed:abstractText
A basic theoretical model that describes the effects of flow in and out of the imaging plane in nuclear magnetic resonance (NMR) images, obtained with the standard pulse sequences single spin echo, multiple spin echo, and inversion recovery, is presented. Theoretically calculated signal values are compared with experimental results obtained from single-slice images of a flow phantom for variable flow velocity v as well as for variable echo time and inversion time at flow velocities less than 10 mm/s, corresponding to those found in cerebrospinal fluid, in capillary systems, and in smaller veins. The quantitative correspondence between theory and experiment is good in the range of velocities studied and for the imaging parameters used, but discrepancies occur when higher velocities are studied. In addition, flow in a capillary model is demonstrated qualitatively for very low linear flow velocities, less than 1 mm/s. It is concluded that the model describes the essentials of the inflow-outflow effect and that this effect can predict the flow dependence of the NMR signal for low flow velocities. Observed differences between model and experiment may be due to effects of flow-induced phase alterations and due to uncertainty in measurements of the relaxation times T1 and T2. The model described here can be extended to suit other types of pulse sequences and to suit multislice imaging. It can also be extended to incorporate flow-induced phase effects.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0363-8715
pubmed:author
pubmed:issnType
Print
pubmed:volume
10
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1006-15
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:articleTitle
Quantitative study of flow dependence in NMR images at low flow velocities.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't