title: Sickle cell anemia: intracranial stenosis and silent cerebral infarcts in children with low risk of stroke.
abstract: OBJECTIVE
  Children with sickle cell anemia (SCA), who have mean blood flow velocities <170 cm/s in the terminal internal carotid (tICA) or middle cerebral (MCA) arteries on transcranial Doppler ultrasonography (TCD), are considered to be at low risk of stroke. The prevalence of intracranial stenosis, which raises the risk of stroke, is not known in these children. Here, we estimated the prevalence of stenosis and explored its association with silent cerebral infarcts determined based on Magnetic Resonance (MR) scans.
  
  
  METHODS
  We studied prospectively a cohort of 67 children with SCA without prior clinically overt stroke or TIA (median age 8.8 years; range limits 2.3-13.1 years; 33 females) and with TCD mean velocity <170 cm/s. They underwent MR imaging of the brain and MR angiography of intracranial arteries.
  
  
  RESULTS
  In 7 children (10.5%, 95% CI: 4.9-20.3%) we found 10 stenoses, including 4 with isolated left tICA stenosis and 3 with multiple stenoses. We found silent infarcts in 26 children (37.7%, 95% CI: 27.2-49.5%). The median number of infarcts in an affected child was 2 (range limits: 1-9), median volume of infarcts was 171 mm(3) (range limits: 7-1060 mm(3)), and median infarct volume in relation to total brain volume was 0.020% (range limits: 0.001-0.101%). The number and volume of infarcts were significantly higher in children with arterial stenosis (both p=0.023).
  
  
  CONCLUSIONS
  The prevalence of intracranial arterial stenosis in children with SCA classified as at low risk of stroke by TCD mean velocity <170 cm/s is high. Children with stenosis are at higher risk of brain parenchymal injury as they have more silent cerebral infarcts.
authors.affiliation: Department of Radiology, Division of Neuroradiology, University of Pennsylvania, Philadelphia, PA, USA; Department of Neurology, Medical University of Silesia, Katowice, Poland.
authors.forename: Michal
authors.initials: M
authors.lastname: Arkuszewski
authors.affiliation: Department of Diagnostic Radiology & Nuclear Medicine, University of Maryland Medical Center, Baltimore, MD, USA; King Khalid University, Abha, The Kingdom of Saudi Arabia. Electronic address: jkrejza@me.com.
authors.forename: Jaroslaw
authors.initials: J
authors.lastname: Krejza
authors.affiliation: Department of Diagnostic Radiology & Nuclear Medicine, University of Maryland Medical Center, Baltimore, MD, USA.
authors.forename: Rong
authors.initials: R
authors.lastname: Chen
authors.affiliation: Department of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, USA; Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, PA, USA.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Ichord
authors.affiliation: Department of Hematology, Children's Hospital of Philadelphia, Philadelphia, PA, USA.
authors.forename: Janet L
authors.initials: JL
authors.lastname: Kwiatkowski
authors.affiliation: Department of Radiology, Division of Neuroradiology, University of Pennsylvania, Philadelphia, PA, USA.
authors.forename: Michel
authors.initials: M
authors.lastname: Bilello
authors.affiliation: Department of Radiology, Children's Hospital of Philadelphia, Philadelphia, PA, USA.
authors.forename: Robert
authors.initials: R
authors.lastname: Zimmerman
authors.affiliation: Department of Hematology, Children's Hospital of Philadelphia, Philadelphia, PA, USA.
authors.forename: Kwaku
authors.initials: K
authors.lastname: Ohene-Frempong
authors.affiliation: Department of Diagnostic Radiology & Nuclear Medicine, University of Maryland Medical Center, Baltimore, MD, USA.
authors.forename: Elias R
authors.initials: ER
authors.lastname: Melhem
mesh_terms: D000293:Adolescent; D000755:Anemia, Sickle Cell / Q000000981:diagnostic imaging / Q000503:physiopathology*; D002544:Cerebral Infarction / Q000150:complications* / Q000000981:diagnostic imaging / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D003251:Constriction, Pathologic / Q000150:complications* / Q000000981:diagnostic imaging / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D002537:Intracranial Arteriosclerosis / Q000150:complications* / Q000000981:diagnostic imaging / Q000453:epidemiology; D008297:Male; D015995:Prevalence; D011379:Prognosis; D011446:Prospective Studies; D020521:Stroke / Q000000981:diagnostic imaging / Q000209:etiology*; D017585:Ultrasonography, Doppler, Transcranial
keywords: Children; Intracranial stenosis; Sickle cell disease; Silent cerebral infarct; Stroke risk; Transcranial Doppler