title: Impact of CT attenuation correction by SPECT/CT in brain perfusion images.
abstract: OBJECTIVE
  The aim of this study was to elucidate the regional differences between brain perfusion single photon emission computed tomography (SPECT) images reconstructed with a uniform attenuation correction using Chang's method (AC-Chang) and a non-uniform attenuation correction with CT using SPECT/CT (AC-CT).
  
  
  METHODS
  SPECT images of a phantom with and without head holder were obtained, and reconstructed images of AC-Chang and AC-CT were compared. Twenty-eight consecutive patients with brain disease examined by SPECT/CT brain perfusion imaging were selected, and images were reconstructed with AC-Chang and AC-CT. The AC-Chang and AC-CT reconstructed images were then compared by voxel-based analysis using three-dimensional stereotactic surface projections.
  
  
  RESULTS
  Counts in the frontal area of the AC-Chang phantom image with head holder were higher than those in the posterior area. Counts in the frontal area of the AC-Chang clinical images were significantly higher than those in the AC-CT images, while the counts in the margin of the frontal lobe and posterior margin of the parietal, occipital cortices and cerebellum of the AC-Chang images were significantly lower. Relative frontal perfusion was 5.0% higher and relative cerebellar perfusion was 4.6% lower in the AC-Chang images relative to the AC-CT images, on average.
  
  
  CONCLUSIONS
  We demonstrated the frontal dominant hyper-perfusion and parieto-occipital and cerebellar hypo-perfusion in brain SPECT images reconstructed with AC-Chang compared to those reconstructed with AC-CT. We suggest that to obtain an accurate attenuation-corrected brain perfusion SPECT image, attenuation correction by Chang's method is inadequate.
authors.affiliation: Department of Radiology, Kinki University, Ohnohigashi, Osakasayama, Osaka, Japan. kishii@hbhc.jp
authors.forename: Kazunari
authors.initials: K
authors.lastname: Ishii
authors.forename: Kohei
authors.initials: K
authors.lastname: Hanaoka
authors.forename: Masahiro
authors.initials: M
authors.lastname: Okada
authors.forename: Seishi
authors.initials: S
authors.lastname: Kumano
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Komeya
authors.forename: Norio
authors.initials: N
authors.lastname: Tsuchiya
authors.forename: Makoto
authors.initials: M
authors.lastname: Hosono
authors.forename: Takamichi
authors.initials: T
authors.lastname: Murakami
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000098:blood supply / Q000000981:diagnostic imaging*; D001927:Brain Diseases / Q000000981:diagnostic imaging / Q000503:physiopathology; D002560:Cerebrovascular Circulation; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods*; D055420:Perfusion Imaging / Q000379:methods*; D019047:Phantoms, Imaging; D049268:Positron-Emission Tomography; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D055815:Young Adult