title: Estimation of regional cerebral blood flow using N-isopropyl-p-123I iodoamphetamine acquisition data from the lungs and brain. An improved non-invasive technique.
abstract: OBJECTIVE
  Previously, we devised a method for estimating123I labeled N-isopropyl-p-iodoamphetamine (123I IMP) arterial blood activity at 10 minutes after intravenous injection of 123I IMP (Ca10) without any blood sampling using 123I IMP autoradiography (ARG) acquisition data, and verified its usefulness for quantification of regional cerebral blood flow (rCBF). In this study, we attempted to develop an improved noninvasive method for estimating rCBF.
  
  
  METHODS
  123I IMP studies with 23 patients and 15O-H2O positron emission tomography (PET) ARG studies with 20 patients were evaluated. Multiple regression analysis was used to estimate an integral of the arterial blood counts during the time after injection of 123I (∫Ca) using parameters from the time series of the lung counts and brain counts as the explanatory variables and the fraction [brain single-photon emission computed tomography (SPECT) average count / the mean of rCBFs (mean CBF) measured by 15O-H2O PET ARG method] as the objective variable.
  
  
  RESULTS
  The regression equation was as follows: Estimated ∫Ca = (7.09×10⁻³ · Cb12) - (1.57×10⁻⁴ · CbpreSPECT) + (9.48×10⁻⁵ · CbpostSPECT) + (1.35×10⁻⁴ · L15) - (6.95×10⁻⁴ · L33) + (7.61×10⁻⁴ · L81) - (0.417), where Cb12: brain count at 12 minutes, Cbpre-SPECT: brain count before SPECT, Cbpost-SPECT: brain count after SPECT, L15, L33, and L81: lung count at 15, 33, and 81 seconds, respectively. The mean CBF values (ml/min/100g) calculated using the estimated ∫Ca values more closely correlated with those measured by 15O-H2O PET ARG method (r = 0.833, p < 0.01) than those obtained by our previous method (r = 0.590, p < 0.01).
  
  
  CONCLUSIONS
  The rCBFs obtained by this method approximated more accurately to the values measured by 15O-H2O PET ARG method than those obtained by our previous method.
authors.forename: S
authors.initials: S
authors.lastname: Abe
authors.affiliation: Katsuhiko Kato, M.D., Ph D., Department of Radiological and Medical Laboratory Sciences, Nagoya University Graduate School of Medicine, 1-20, Daikominami 1-chome, Higashi-ku, Nagoya 461-8673, Japan, Tel. +81/52/719-1590; Fax +81/52/719-1589, E-mail: katokt@med.nagoya-u.ac.jp.
authors.forename: K
authors.initials: K
authors.lastname: Kato
authors.forename: Y
authors.initials: Y
authors.lastname: Takahashi
authors.forename: N
authors.initials: N
authors.lastname: Fujita
authors.forename: M
authors.initials: M
authors.lastname: Ikeda
authors.forename: N
authors.initials: N
authors.lastname: Ota
authors.forename: Y
authors.initials: Y
authors.lastname: Kajita
authors.forename: S
authors.initials: S
authors.lastname: Yamamoto
authors.forename: S
authors.initials: S
authors.lastname: Naganawa
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D001345:Autoradiography / Q000379:methods*; D001783:Blood Flow Velocity; D001921:Brain / Q000000981:diagnostic imaging / Q000502:physiology*; D002560:Cerebrovascular Circulation; D003198:Computer Simulation; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D005260:Female; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D019275:Radiopharmaceuticals
keywords: 123I IMP; 15O-H2O; Cerebral blood flow; PET; SPECT