title: Proposal of blood volume-corrected model for quantification of regional cerebral blood flow with H2 15O-PET and its application to AVF.
abstract: OBJECTIVE
  It is generally assumed that vascular tracer activity is negligible in the quantification of regional cerebral blood flow (rCBF) with H2 15O and positron emission tomography (PET) under normal conditions. We attempted to surpass the assumption of abnormal vascular conditions where the vascular tracer activity is significant by introducing the vascular component into the model.
  
  
  METHODS
  H2 15O-dynamic and C15O PET scans were performed in an arteriovenous fistula (AVF) patient. Time-activity curves of regions of interest (ROIs) were analyzed with nonlinear least-square approximation to estimate the rCBF and fractional arterial blood volume (v(a)) simultaneously with the proposed model and the standard model.
  
  
  RESULTS
  The proposed model curve showed a fit to the time-activity curve of H2 15O at an ROI containing an enlarged vascular space induced by the AVF. The relation between the estimated v(a) and CBV obtained with C15O-PET revealed that the ratio of v(a) to CBV was approximately 0.23. The estimated rCBF with the proposed model in nonlesion ROIs corresponded to those of the standard model, with the estimated V(d) 0.94 ml/ml.
  
  
  CONCLUSIONS
  The results supported the hypothesis that the blood volume-corrected model is applicable to the quantification of rCBF in a region with abnormal vascular structure. Furthermore, one of the advantages of the model is the feasibility of simultaneous estimation of the rCBF and arterial blood volume with dynamic-H2 15O PET scans.
authors.affiliation: Department of Radiology, Faculty of Medicine, The University of Tokyo, 3-7-1 Hongo, Tokyo, Japan. sekichie@nirs.go.jp
authors.forename: Chie
authors.initials: C
authors.lastname: Seki
authors.forename: Toshimitsu
authors.initials: T
authors.lastname: Momose
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Kojima
authors.forename: Yasuto
authors.initials: Y
authors.lastname: Sasaki
authors.forename: Kuni
authors.initials: K
authors.lastname: Ohtomo
authors.forename: Ikuo
authors.initials: I
authors.lastname: Yokoyama
mesh_terms: D001810:Blood Volume; D001921:Brain / Q000098:blood supply* / Q000000981:diagnostic imaging*; D020785:Central Nervous System Vascular Malformations / Q000000981:diagnostic imaging*; D002560:Cerebrovascular Circulation; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010104:Oxygen Radioisotopes; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D014867:Water
chemical_list: D010104:Oxygen Radioisotopes; D019275:Radiopharmaceuticals; D014867:Water