Linked Life Data

1330139

Source:http://linkedlifedata.com/resource/pubmed/id/1330139

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1992-12-22
pubmed:abstractText
A vast data base exists for QCT measurements of bone mineral density (BMD) referenced to K2HPO4 in water (liquid) standards. To effectively utilize the more stable hydroxyapatite in water-equivalent plastic (solid) standards that have recently been introduced, it will be necessary to derive conversion relations. A study was performed to investigate the dependence of these relations upon x-ray tube voltage, marrow composition, and patient body size. Test objects included five diverse composition vertebral marrow inserts within three different size lumbar simulators and an L1 vertebra within a Humanoid phantom. The calibration standards were manufactured by Image Analysis, and all data were acquired with a GE 9800 CT scanner operated at 80 kVp and 140 kVp. Least square fits to corresponding liquid versus solid referenced BMD measurements of the inserts all had r's > 0.999. SEEs, < 2 mg/ml, and intercepts of approximately 0. The slopes (BMDK2HPO4/BMDhydroxyapatite) for the various body sizes were all about the same with values of 0.86, 0.81, and 0.96 to 1.02 for the single-energy@80 kVp, single-energy@140 kVp, and dual-energy measurements, respectively. Corresponding ratios for the Humanoid vertebra were 0.86, 0.82, and 0.96. The conversion relations were essentially independent of marrow composition and body size but did depend upon kVp. Finally, although the solid standards are more stable, they may still exhibit problems, and these are discussed.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0169-6009
pubmed:author
pubmed:issnType
Print
pubmed:volume
19
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
145-58
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1992
pubmed:articleTitle
Conversion relations for quantitative CT bone mineral densities measured with solid and liquid calibration standards.
pubmed:affiliation
Department of Radiology, University of Washington, Seattle.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.