title: The brain in children: is contrast enhancement really needed after obtaining normal unenhanced CT results?
abstract: OBJECTIVE
  To retrospectively determine and compare the sensitivity and specificity of unenhanced and contrast material-enhanced computed tomography (CT) (reference standard) in the diagnosis of brain abnormalities and to evaluate any change in diagnosis that resulted from the contrast-enhanced study.
  
  
  METHODS
  This study was approved by the local research ethics board; the requirement for informed consent was waived. The authors reviewed the unenhanced and contrast-enhanced CT scans of the brain obtained in 353 children for indications other than trauma. There were 196 boys and 157 girls aged 0 months to 17.8 years. Scans were read independently by two pediatric neuroradiologists who were blinded to clinical information. The diagnosis for each scan was recorded according to the anatomic section (supratentorial, infratentorial, ventricles, and skull). The final diagnosis was classified as normal, abnormal, or equivocal. kappa Statistics, with 95% confidence intervals, were reported, and the sensitivity, specificity, positive predictive value, and negative predictive value were calculated.
  
  
  RESULTS
  Interreader agreement for different anatomic regions varied between good (kappa coefficient, 0.63) and very good (kappa coefficient, 0.88) for unenhanced and contrast-enhanced scans. Sensitivity, specificity, positive predictive value, and negative predictive value for unenhanced scans were 97%, 89%, 87%, and 97%, respectively. The use of contrast material led to a change in the original normal or equivocal diagnosis to an abnormal diagnosis for only five (2.7%) of the 183 normal unenhanced scans.
  
  
  CONCLUSIONS
  Unenhanced CT of developing brains has high sensitivity and specificity in the diagnosis of pathologic findings. The use of intravenous contrast material after unenhanced CT of the brain in children did not change the diagnosis frequently.
authors: Department of Diagnostic Imaging, The Hospital for Sick Children, and Department of Public Health, Family and Community Medicine, University of Toronto, Ontario, Canada M5G 1X8.
authors: Helen M
authors: HM
authors: Branson
authors: Andrea S
authors: AS
authors: Doria
authors: Rahim
authors: R
authors: Moineddin
authors: Manohar M
authors: MM
authors: Shroff
mesh_terms: D000293:Adolescent; D001927:Brain Diseases / Q000000981:diagnostic imaging*; D002648:Child; D002675:Child, Preschool; D003287:Contrast Media / Q000008:administration & dosage; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007275:Injections, Intravenous; D008297:Male; D011237:Predictive Value of Tests; D011857:Radiographic Image Interpretation, Computer-Assisted; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media