title: Sickle cell disease and transcranial Doppler imaging: inter-hemispheric differences in blood flow Doppler parameters.
abstract: OBJECTIVE
  to establish reference values of interhemispheric differences and ratios of blood flow Doppler parameters in the terminal internal carotid artery, middle cerebral artery, and anterior cerebral artery in children with sickle cell anemia.
  
  
  METHODS
  fifty-seven out of 74 recruited children (mean age, 7.8 ± 3.4 years; range limits, 3-14 years), who were free of neurological deficits and intracranial narrowing detectable by MRA and had flow velocities <170 cm/s by conventional transcranial Doppler ultrasound, underwent transcranial color-coded duplex ultrasonography. Reference limits of flow parameters corrected and uncorrected for the angle of insonation were estimated using tolerance intervals, with P=0.90 for all possible data values from 95% of a population.
  
  
  RESULTS
  reference limits for left-to-right differences in cm/s in the mean angle-corrected and uncorrected flow velocities were -56 to 53 and -72 to 75 for middle cerebral artery, -49 to 57 and -81 to 91 for anterior cerebral artery, and -55 to 64 and -73 to 78 for terminal internal carotid artery, respectively. Respective reference limits for left-to-right velocity ratios were 0.31 to 1.84 and 0.38 to 1.75 for middle cerebral artery, 0.48 to 2.99 and 0.46 to 2.89 for anterior cerebral artery, and 0.61 to 2.56 and 0.56 to 2.23 for terminal internal carotid artery.
  
  
  CONCLUSIONS
  the study provides reference limits of interhemispheric differences and ratios of blood flow Doppler parameters that may be helpful in identification of intracranial arterial narrowing in children with sickle cell disease undergoing ultrasound screening for stroke prevention.
authors.affiliation: Department of Radiology, Division of Neuroradiology, University of Pennsylvania, Philadelphia, PA 19104, USA. Jaroslaw.Krejza@uphs.upenn.edu
authors.forename: Jaroslaw
authors.initials: J
authors.lastname: Krejza
authors.forename: Rong
authors.initials: R
authors.lastname: Chen
authors.forename: Grzegorz
authors.initials: G
authors.lastname: Romanowicz
authors.forename: Janet L
authors.initials: JL
authors.lastname: Kwiatkowski
authors.forename: Rebecca
authors.initials: R
authors.lastname: Ichord
authors.forename: Michal
authors.initials: M
authors.lastname: Arkuszewski
authors.forename: Robert
authors.initials: R
authors.lastname: Zimmerman
authors.forename: Kwaku
authors.initials: K
authors.lastname: Ohene-Frempong
authors.forename: Lisa
authors.initials: L
authors.lastname: Desiderio
authors.forename: Elias R
authors.initials: ER
authors.lastname: Melhem
mesh_terms: D000755:Anemia, Sickle Cell / Q000150:complications / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D020771:Anterior Cerebral Artery / Q000000981:diagnostic imaging / Q000503:physiopathology; D001783:Blood Flow Velocity; D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging / Q000503:physiopathology; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D020768:Middle Cerebral Artery / Q000000981:diagnostic imaging / Q000503:physiopathology; D011446:Prospective Studies; D020521:Stroke / Q000000981:diagnostic imaging / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control; D017585:Ultrasonography, Doppler, Transcranial