Source:http://linkedlifedata.com/resource/pubmed/id/17326185
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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
3
|
| pubmed:dateCreated |
2007-3-5
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| pubmed:abstractText |
In high-field MRI severe problems with respect to B(1) (+) uniformity and specific absorption rate (SAR) deposition pose a great challenge to whole-body imaging. In this study the potential of a phased array transmit coil is investigated to simultaneously reduce B(1) (+) nonuniformity and SAR deposition. This was tested by performing electromagnetic simulations of a phased array TEM coil operating at 128 MHz loaded with two different homogeneous elliptical phantoms and four dielectric patient models. It was shown that the wave interference of a circularly polarized RF field with an ellipse and a pelvis produces largely identical B(1) (+) and electric field patterns. Especially for obese patients, this results in large B(1) (+) nonuniformity and global areas with elevated SAR deposition. It is demonstrated that a phased array transmit coil can reduce these phenomena. The technique was especially successful in suppressing SAR hotspots with a decrease up to 50%. The application of optimized settings for an ellipse to the patient models leads to comparable results as obtained with the patient-specific optimizations. This suggests that generic phase/amplitude port settings are possible, requiring no preinformation about patient-specific RF fields. Such a scheme would, due to its simultaneous B(1) (+) homogenization and extra SAR margin, have many benefits for whole-body imaging at 3 T.
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| pubmed:language |
eng
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| pubmed:journal | |
| pubmed:citationSubset |
IM
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| pubmed:status |
MEDLINE
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| pubmed:month |
Mar
|
| pubmed:issn |
0740-3194
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| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:volume |
57
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| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
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| pubmed:pagination |
577-86
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| pubmed:meshHeading |
pubmed-meshheading:17326185-Absorption,
pubmed-meshheading:17326185-Female,
pubmed-meshheading:17326185-Humans,
pubmed-meshheading:17326185-Magnetic Resonance Imaging,
pubmed-meshheading:17326185-Male,
pubmed-meshheading:17326185-Phantoms, Imaging,
pubmed-meshheading:17326185-Radio Waves,
pubmed-meshheading:17326185-Whole Body Imaging
|
| pubmed:year |
2007
|
| pubmed:articleTitle |
Simultaneous B1 + homogenization and specific absorption rate hotspot suppression using a magnetic resonance phased array transmit coil.
|
| pubmed:affiliation |
Department of Radiotherapy, University Medical Center Utrecht, Utrecht, The Netherlands.
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| pubmed:publicationType |
Journal Article
|