title: Acute pediatric encephalitis neuroimaging: single-institution series as part of the California encephalitis project.
abstract: OBJECTIVE
  Diagnosing pediatric encephalitis is challenging because of varied clinical presentation, nonspecific neuroimaging features, and rare confirmation of causality. We reviewed acute neuroimaging of children with clinically suspected encephalitis to identify findings that may correlate with etiology and length of stay.
  
  
  METHODS
  Imaging of 141 children with clinically suspected encephalitis as part of The California Encephalitis Project from 2005 to 2012 at a single institution was reviewed to compare the extent of neuroimaging abnormalities to patient age, gender, length of stay, and unknown, possible, or confirmed pathogen. Scan review was blinded and categorized by extent and distribution of abnormal findings.
  
  
  RESULTS
  Abnormal findings were evident on 23% (22/94) of computed tomography and 50% (67/134) of magnetic resonance imaging studies in the acute setting. Twenty children with normal admission computed tomography had abnormal findings on magnetic resonance imaging performed within 2 days. Length of stay was significantly longer among children with abnormal acute magnetic resonance imaging (P < 0.001) and correlated with increased complexity (Spearman rho = 0.4, P < 0.001) categorized as: no imaging abnormality, meningeal enhancement and/or focal nonenhancing lesion, multifocal lesions, confluent lesions, and lesions plus diffusion restriction, hemorrhage, or hydrocephalus. There was no correlation between neuroimaging findings and an identifiable pathogen (P = 0.8).
  
  
  CONCLUSIONS
  Abnormal magnetic resonance imaging findings are more common than abnormal computed tomography findings in pediatric encephalitis. Increasing complexity of magnetic resonance imaging findings correlated with disease severity as evidenced by longer length of stay, but were not specific for an identifiable pathogen using a standardized diagnostic encephalitis panel.
authors.affiliation: Department of Radiology, University of California San Diego Health System, San Diego, California. Electronic address: jbykowski@ucsd.edu.
authors.forename: Julie
authors.initials: J
authors.lastname: Bykowski
authors.affiliation: San Diego Imaging, Rady Children's Hospital, San Diego, California.
authors.forename: Peter
authors.initials: P
authors.lastname: Kruk
authors.affiliation: Division of Child Neurology, Department of Neurosciences, University of California San Diego Health System and Rady Children's Hospital, San Diego, California.
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Gold
authors.affiliation: California Department of Public Health, Richmond, California.
authors.forename: Carol A
authors.initials: CA
authors.lastname: Glaser
authors.affiliation: California Department of Public Health, Richmond, California.
authors.forename: Heather
authors.initials: H
authors.lastname: Sheriff
authors.affiliation: Division of Child Neurology, Department of Neurosciences, University of California San Diego Health System and Rady Children's Hospital, San Diego, California.
authors.forename: John R
authors.initials: JR
authors.lastname: Crawford
mesh_terms: D000293:Adolescent; D001921:Brain / Q000473:pathology*; D002140:California; D002648:Child; D002675:Child, Preschool; D004660:Encephalitis / Q000473:pathology*; D005260:Female; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D055815:Young Adult
keywords: M. pneumoniae; computed tomography; encephalitis; magnetic resonance imaging