title: Assessment of the tracer delay effect in whole-brain computed tomography perfusion: results in patients without known neuroanatomic abnormalities.
abstract: OBJECTIVE
  Whole-brain computed tomography perfusion (CTP) data sets generated by tracer delay-insensitive singular value decomposition plus (SVD+) and standard singular value decomposition (sSVD) deconvolution algorithms were evaluated to quantify relatedness and discrepancies in CTP results.
  
  
  METHODS
  Twenty females with symmetrical hemispheric CTP maps indicative of brain tissue without apparent abnormalities were studied. Tissue-specific CTP values were analyzed.
  
  
  RESULTS
  Standard SVD values were higher than SVD+ for cerebral blood flow. Other CTP values had minimal differences across brain regions. All simple linear regression models were statistically significant (P < 0.05) except for cerebral blood flow in white matter (P = 0.06). Cerebral blood volume had a good model fit, and mean transit time, a poor fit.
  
  
  CONCLUSIONS
  Corresponding fitted CTP values for sSVD and SVD+ based on regression equations for brain-tissue types are presented. Additional research is required to compare SVD+ and sSVD in disease states when significant hemodynamic brain alterations are present.
authors.affiliation: Department of Research and Education, Tier 7 Research and Development, Portland, OR 97229, USA. erichansonmd@gmail.com
authors.forename: Eric H
authors.initials: EH
authors.lastname: Hanson
authors.forename: Cayce J
authors.initials: CJ
authors.lastname: Roach
authors.forename: Kirtly J
authors.initials: KJ
authors.lastname: Day
authors.forename: Keith R
authors.initials: KR
authors.lastname: Peters
authors.forename: William G
authors.initials: WG
authors.lastname: Bradley
authors.forename: Kaushik
authors.initials: K
authors.lastname: Ghosh
authors.forename: Phillip W
authors.initials: PW
authors.lastname: Patton
authors.forename: Robert C
authors.initials: RC
authors.lastname: McMurray
authors.forename: William W
authors.initials: WW
authors.lastname: Orrison
mesh_terms: D000328:Adult; D000465:Algorithms; D019540:Area Under Curve; D001810:Blood Volume; D001921:Brain / Q000098:blood supply* / Q000000981:diagnostic imaging*; D002545:Brain Ischemia / Q000000981:diagnostic imaging; D002560:Cerebrovascular Circulation; D006259:Craniocerebral Trauma / Q000000981:diagnostic imaging; D005260:Female; D006261:Headache / Q000000981:diagnostic imaging; D006801:Humans; D016014:Linear Models; D008875:Middle Aged; D011829:Radiation Dosage; D012016:Reference Values; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014283:Triiodobenzoic Acids / Q000493:pharmacokinetics*
chemical_list: D014283:Triiodobenzoic Acids; C054871:ioversol