title: Effects of blood ΔR2* non-linearity on absolute perfusion quantification using DSC-MRI: comparison with Xe-133 SPECT.
abstract: OBJECTIVE
  To evaluate whether a non-linear blood ΔR2*-versus-concentration relationship improves quantitative cerebral blood flow (CBF) estimates obtained by dynamic susceptibility contrast (DSC) MRI in a comparison with Xe-133 SPECT CBF in healthy volunteers.
  
  
  METHODS
  Linear as well as non-linear relationships between ΔR2* and contrast agent concentration in blood were applied to the arterial input function (AIF) and the venous output function (VOF) from DSC-MRI. To reduce partial volume effects in the AIF, the arterial time integral was rescaled using a corrected VOF scheme.
  
  
  RESULTS
  Under the assumption of proportionality between the two modalities, the relationship CBF(MRI)=0.58CBF(SPECT) (r=0.64) was observed using the linear relationship and CBF(MRI)=0.51CBF(SPECT) (r=0.71) using the non-linear relationship.
  
  
  CONCLUSIONS
  A smaller ratio of the VOF time integral to the AIF time integral and a somewhat better correlation between global DSC-MRI and Xe-133 SPECT CBF estimates were observed using the non-linear relationship. The results did not, however, confirm the superiority of one model over the other, potentially because realistic AIF signal data may well originate from a combination of blood and surrounding tissue.
authors: Department of Medical Radiation Physics, Lund University, Lund, Sweden. Linda.Knutsson@med.lu.se
authors: Linda
authors: L
authors: Knutsson
authors: Freddy
authors: F
authors: Ståhlberg
authors: Ronnie
authors: R
authors: Wirestam
authors: Matthias J
authors: MJ
authors: van Osch
mesh_terms: D000280:Administration, Inhalation; D000328:Adult; D000368:Aged; D000465:Algorithms; D016477:Artifacts; D001783:Blood Flow Velocity / Q000502:physiology; D001810:Blood Volume / Q000502:physiology; D001921:Brain / Q000000981:diagnostic imaging / Q000502:physiology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D003287:Contrast Media / Q000008:administration & dosage; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008297:Male; D008875:Middle Aged; D017711:Nonlinear Dynamics; D055420:Perfusion Imaging / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D014980:Xenon Radioisotopes / Q000008:administration & dosage
chemical_list: D003287:Contrast Media; D014980:Xenon Radioisotopes