title: Pixel-by-pixel precise delay correction for measurement of cerebral hemodynamic parameters in H215O PET study.
abstract: OBJECTIVE
  A new method of delay time estimation was proposed to measure precise cerebral blood flow (CBF) and arterial-to-capillary blood volume (V0) using15O-water PET.
  
  
  METHODS
  Nineteen patients with unilateral arterial stenoocclusive lesions were studied to evaluate hemodynamic status before treatment. The delay time of each pixel was calculated using least squares fitting with an arterial blood input curve adjusted to the internal carotid artery counts at the skull base. Pixel-by-pixel delay estimation provided a delay map image that could be used for precise calculation of CBF and V0using a one-tissue compartment model, and the values from this method were compared with those from the slice-by-slice correction method.
  
  
  RESULTS
  The affected side showed a longer delay time than the contralateral cerebral hemisphere. Although the mean cortical CBF values were not different between the two methods, the slice-by-slice delay correction overestimated CBF in the hypo perfused area. The scatter plot of V0pixel values showed significant difference between the two correction methods where the slice-by-slice delay correction significantly overestimated V0in the whole brain (P < 0.05).
  
  
  CONCLUSIONS
  Pixel-by-pixel delay correction provides delay images as well as better estimation of CBF and V0, thus offering useful and beneficial information for the treatment of cerebrovascular disease.
authors.affiliation: Biomedical Imaging Research Center, University of Fukui, 23-3, Matsuoka-Shimaizuki, Eiheiji-cho, Fukui, 910-1193, Japan.
authors.forename: Muhammad M
authors.initials: MM
authors.lastname: Islam
authors.affiliation: Biomedical Imaging Research Center, University of Fukui, 23-3, Matsuoka-Shimaizuki, Eiheiji-cho, Fukui, 910-1193, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Tsujikawa
authors.affiliation: Biomedical Imaging Research Center, University of Fukui, 23-3, Matsuoka-Shimaizuki, Eiheiji-cho, Fukui, 910-1193, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Mori
authors.affiliation: Biomedical Imaging Research Center, University of Fukui, 23-3, Matsuoka-Shimaizuki, Eiheiji-cho, Fukui, 910-1193, Japan.
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Kiyono
authors.affiliation: Biomedical Imaging Research Center, University of Fukui, 23-3, Matsuoka-Shimaizuki, Eiheiji-cho, Fukui, 910-1193, Japan. okazawa@u-fukui.ac.jp.
authors.forename: Hidehiko
authors.identifier: http://orcid.org/0000-0001-7046-3383
authors.initials: H
authors.lastname: Okazawa
mesh_terms: D000368:Aged; D000465:Algorithms; D001921:Brain / Q000098:blood supply* / Q000000981:diagnostic imaging* / Q000503:physiopathology; D002340:Carotid Artery Diseases / Q000000981:diagnostic imaging / Q000503:physiopathology; D002536:Cerebral Arteries / Q000000981:diagnostic imaging / Q000503:physiopathology; D002560:Cerebrovascular Circulation / Q000502:physiology; D005260:Female; D007839:Functional Laterality; D006801:Humans; D016018:Least-Squares Analysis; D008297:Male; D010104:Oxygen Radioisotopes; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D014867:Water
chemical_list: D010104:Oxygen Radioisotopes; D019275:Radiopharmaceuticals; D014867:Water
keywords: Arterial-to-capillary blood volume (V 0); Cerebral blood flow; Delay correction; H2 15O PET; Pixelwise calculation