title: Database of normal human cerebral blood flow measured by SPECT: II. Quantification of I-123-IMP studies with ARG method and effects of partial volume correction.
abstract: The limited spatial resolution of SPECT causes a partial volume effect (PVE) and can lead to the significant underestimation of regional tracer concentration in the small structures surrounded by a low tracer concentration, such as the cortical gray matter of an atrophied brain. The aim of the present study was to determine, using 123I-IMP and SPECT, normal CBF of elderly subjects with and without PVE correction (PVC), and to determine regional differences in the effect of PVC and their association with the regional tissue fraction of the brain.
  
  
  METHODS
  Quantitative CBF SPECT using 123I-IMP was performed in 33 healthy elderly subjects (18 males, 15 females, 54-74 years old) using the autoradiographic method. We corrected CBF for PVE using segmented MR images, and analyzed quantitative CBF and regional differences in the effect of PVC using tissue fractions of gray matter (GM) and white matter (WM) in regions of interest (ROIs) placed on the cortical and subcortical GM regions and deep WM regions.
  
  
  RESULTS
  The mean CBF in GM-ROIs were 31.7 +/- 6.6 and 41.0 +/- 8.1 ml/100 g/min for males and females, and in WM-ROIs, 18.2 +/- 0.7 and 22.9 +/- 0.8 ml/100 g/min for males and females, respectively. The mean CBF in GM-ROIs after PVC were 50.9 +/- 12.8 and 65.8 +/- 16.1 ml/100 g/min for males and females, respectively. There were statistically significant differences in the effect of PVC among ROIs, but not between genders. The effect of PVC was small in the cerebellum and parahippocampal gyrus, and it was large in the superior frontal gyrus, superior parietal lobule and precentral gyrus.
  
  
  CONCLUSIONS
  Quantitative CBF in GM recovered significantly, but did not reach values as high as those obtained by invasive methods or in the H2(15)O PET study that used PVC. There were significant regional differences in the effect of PVC, which were considered to result from regional differences in GM tissue fraction, which is more reduced in the frontoparietal regions in the atrophied brain of the elderly.
authors.affiliation: Department of Nuclear Medicine and Radiology, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan. kenta@idac.tohoku.ac.jp
authors.forename: Kentaro
authors.initials: K
authors.lastname: Inoue
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ito
authors.forename: Miho
authors.initials: M
authors.lastname: Shidahara
authors.forename: Ryoi
authors.initials: R
authors.lastname: Goto
authors.forename: Shigeo
authors.initials: S
authors.lastname: Kinomura
authors.forename: Kazunori
authors.initials: K
authors.lastname: Sato
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Taki
authors.forename: Ken
authors.initials: K
authors.lastname: Okada
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Kaneta
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Fukuda
mesh_terms: D000368:Aged; D000465:Algorithms; D016477:Artifacts; D001921:Brain / Q000098:blood supply* / Q000000981:diagnostic imaging* / Q000378:metabolism; D002560:Cerebrovascular Circulation; D016208:Databases, Factual; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods* / Q000592:standards; D020367:Iofetamine / Q000493:pharmacokinetics; D008297:Male; D008875:Middle Aged; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014018:Tissue Distribution; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods* / Q000592:standards
chemical_list: D019275:Radiopharmaceuticals; D020367:Iofetamine