title: Comparing segmented ASL perfusion of vascular territories using manual versus semiautomated techniques in children with sickle cell anemia.
abstract: OBJECTIVE
  Elevated cerebral blood flow (CBF) in sickle cell anemia (SCA) is an adaptive pathophysiologic response associated with decreased vascular reserve and increased risk for ischemia. We compared manual (M) and semiautomated (SA) vascular territory delineation to facilitate standardized evaluation of CBF in children with SCA.
  
  
  METHODS
  ASL perfusion values from 21 children were compared for gray matter and white matter (WM) in vascular territories defined by M and SA delineation. SA delineated CBF was compared with clinical and hematologic variables acquired within 4 weeks of the MRI.
  
  
  RESULTS
  CBF measurements from M (MCA 82 left, 79 right) and SA (MCA 81 left, 81 right) delineated territories were highly correlated (R = 0.99, P < 0.0001). Bland-Altman plots had close-fitting limits of agreement of -1.8 to -3.5 lower limit and 0 to 1.8 upper limit. SA vascular territory delineation was comparable to the expert delineation with a kappa index of 0.62-0.85 and was considerably faster. Median territorial CBF values did not differ by gender or age. WM perfusion in the posterior cerebral artery territories was positively correlated with degree of hemolysis (R = 0.58, P = 0.01 left, 0.73, P < 0.001 right) and negatively correlated with hemoglobin (R = -0.48; P = 0.03 left; -0.47; P = 0.04 right) and hemoglobin F (R = -0.42; P = .09 left; -0.47; P = 0.049 right).
  
  
  CONCLUSIONS
  We established the validity of the SA method, which in our experience was much faster than the M method for delineation of vascular territories. Associations between CBF and hematologic variables may demonstrate pathophysiologic changes that contribute to clinical variation in CBF.
authors.affiliation: Department of Radiological Sciences, St Jude Children's Research Hospital, Memphis, Tennessee, USA.
authors.forename: Kathleen J
authors.initials: KJ
authors.lastname: Helton
authors.forename: John O
authors.initials: JO
authors.lastname: Glass
authors.forename: Wilburn E
authors.initials: WE
authors.lastname: Reddick
authors.forename: Amir
authors.initials: A
authors.lastname: Paydar
authors.forename: Arash R
authors.initials: AR
authors.lastname: Zandieh
authors.forename: Rachna
authors.initials: R
authors.lastname: Dave
authors.forename: Matthew P
authors.initials: MP
authors.lastname: Smeltzer
authors.forename: Song
authors.initials: S
authors.lastname: Wu
authors.forename: Jane
authors.initials: J
authors.lastname: Hankins
authors.forename: Banu
authors.initials: B
authors.lastname: Aygun
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Ogg
mesh_terms: D000293:Adolescent; D000755:Anemia, Sickle Cell / Q000503:physiopathology*; D002560:Cerebrovascular Circulation; D002648:Child; D002675:Child, Preschool; D056324:Diffusion Tensor Imaging / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D011446:Prospective Studies
keywords: ASL; semiautomated perfusion; sickle cell anemia