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rdf:type |
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lifeskim:mentions |
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pubmed:issue |
3
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pubmed:dateCreated |
2008-1-15
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pubmed:abstractText |
Variance estimates can be used in conjunction with scientifically meaningful effect sizes to design experiments with type II error control. Here we present estimates of intra- and inter-subject variances for region of interest (ROI) from resting cerebral blood flow (CBF) maps obtained using whole brain, spin echo echoplanar (SE-EPI) continuous arterial spin labeling (CASL) imaging on 52 elderly subjects (age=70.5+/-7.9 years, 29 males). There was substantial intrasubject systematic variability in CBF of gray matter ROIs corresponding to a range of standard deviations=[39-168] (ml/(100 g min)). This variability was mainly due to two factors: (1) an expected inverse relationship between ROI volume and intrasubject variance and (2) an increased effective post-labeling delay for more superior slices acquired later in the sequence. For example, intrasubject variance in Brodmann area 4 (BA 4) was approximately 8 times larger than in hippocampus, despite their similar gray matter volumes. Estimated ROI-wise power was computed for various numbers of acquired CBF images, numbers of subjects, and CBF effect sizes for two experimental designs: independent sample t-test and paired t-test. The theoretical effects of pulse sequence and field strength on general applicability of these results are discussed.
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pubmed:grant |
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pubmed:commentsCorrections |
http://linkedlifedata.com/resource/pubmed/commentcorrection/18036834-10632106,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18036834-10800040,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18036834-11064401,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18036834-11506549,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18036834-11771995,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18036834-11979571,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18036834-12210932,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18036834-12637292,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18036834-12704760,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18036834-12880848,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18036834-12887982,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18036834-12939768,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18036834-14635149,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18036834-14741682,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18036834-15057170,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18036834-15325350,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18036834-15345803,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18036834-15455459,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18036834-15588616,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18036834-15653178,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18036834-15716390,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18036834-15844087,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18036834-15947061,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18036834-16086314,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18036834-16533609,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18036834-16731365,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18036834-16948114,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18036834-8898697,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18036834-9211380,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18036834-9680569,
http://linkedlifedata.com/resource/pubmed/commentcorrection/18036834-9727941
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pubmed:language |
eng
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pubmed:journal |
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pubmed:citationSubset |
IM
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pubmed:chemical |
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pubmed:status |
MEDLINE
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pubmed:month |
Feb
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pubmed:issn |
1053-8119
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pubmed:author |
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pubmed:issnType |
Print
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pubmed:day |
1
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pubmed:volume |
39
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
1246-56
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pubmed:dateRevised |
2009-11-18
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pubmed:meshHeading |
pubmed-meshheading:18036834-Aged,
pubmed-meshheading:18036834-Algorithms,
pubmed-meshheading:18036834-Analysis of Variance,
pubmed-meshheading:18036834-Cerebral Arteries,
pubmed-meshheading:18036834-Cerebrovascular Circulation,
pubmed-meshheading:18036834-Cohort Studies,
pubmed-meshheading:18036834-Echo-Planar Imaging,
pubmed-meshheading:18036834-Humans,
pubmed-meshheading:18036834-Image Processing, Computer-Assisted,
pubmed-meshheading:18036834-Reproducibility of Results,
pubmed-meshheading:18036834-Spin Labels
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pubmed:year |
2008
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pubmed:articleTitle |
An investigation of statistical power for continuous arterial spin labeling imaging at 1.5 T.
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pubmed:affiliation |
The Department of Radiology, Columbia University College of Physicians and Surgeons, 630 West 168th Street, Columbia University, New York, New York 10032, USA. ia2026@columbia.edu
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pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't,
Research Support, N.I.H., Extramural
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