title: Effect of vascular stenosis on perfusion-weighted imaging; differences between calculation algorithms.
abstract: OBJECTIVE
  To determine the most suitable postprocessing technique for magnetic resonance (MR) perfusion imaging in patients with vascular stenosis, by comparing the cerebral blood flow (CBF) maps of single photon emission tomography (SPECT) and perfusion MR imaging (MRI).
  
  
  METHODS
  In 15 consecutive patients (14 men and one woman, mean age 73.9 +/- 6.0 years) with stenosis of common carotid artery (CCA) or internal carotid artery (ICA) of more than 75%, both brain perfusion MRI and brain perfusion SPECT were performed. From perfusion MR images, CBF maps were calculated with the first moment, singular value decomposition (SVD), and block circulant SVD (b-SVD) methods, and CBF maps from each algorithm were compared with those from SPECT.
  
  
  RESULTS
  The b-SVD method had the best correlation with SPECT (R = 0.814), followed by the first moment method (R = 0.776) and the SVD method (R = 0.723). The b-SVD method has the least mean difference with SPECT (0.118), the first moment method also had less difference (0.121), and the SVD had greatest mean difference (0.164).
  
  
  CONCLUSIONS
  Our results suggest that in patients with vascular impairment the b-SVD method will be the technique of choice rather than SVD or first moment method.
authors.affiliation: Department of Radiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan. matsu@koto.kpu-m.ac.jp
authors.forename: Shigenori
authors.initials: S
authors.lastname: Matsushima
authors.forename: Takao
authors.initials: T
authors.lastname: Kubota
authors.forename: Kei
authors.initials: K
authors.lastname: Yamada
authors.forename: Kentaro
authors.initials: K
authors.lastname: Akazawa
authors.forename: Terutoshi
authors.initials: T
authors.lastname: Masunami
authors.forename: Hirotoshi
authors.initials: H
authors.lastname: Ito
authors.forename: Yo
authors.initials: Y
authors.lastname: Ushijima
authors.forename: Kei
authors.initials: K
authors.lastname: Owada
authors.forename: Hiroyasu
authors.initials: H
authors.lastname: Sasajima
authors.forename: Katsuyoshi
authors.initials: K
authors.lastname: Mineura
authors.forename: Tsunehiko
authors.initials: T
authors.lastname: Nishimura
mesh_terms: D000368:Aged; D000465:Algorithms; D002545:Brain Ischemia / Q000175:diagnosis* / Q000000981:diagnostic imaging; D016893:Carotid Stenosis / Q000000981:diagnostic imaging / Q000503:physiopathology*; D002560:Cerebrovascular Circulation; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D020521:Stroke / Q000175:diagnosis* / Q000000981:diagnostic imaging; D015899:Tomography, Emission-Computed, Single-Photon