title: Accuracy of pre-contrast imaging in abdominal magnetic resonance imaging of pediatric oncology patients.
abstract: BACKGROUND
  Safety concerns are increasingly raised regarding the use of gadolinium-based contrast media for MR imaging.
  
  
  OBJECTIVE
  To determine the accuracy of pre-contrast abdominal MR imaging for lesion detection and characterization in pediatric oncology patients.
  
  
  METHODS
  We included 120 children (37 boys and 83 girls; mean age 8.94 years) referred by oncology services. Twenty-five had MRI for the first time and 95 were follow-up scans. Two authors independently reviewed pre-contrast MR images to note the following information about the lesions: location, number, solid vs. cystic and likely nature. Pre- and post-contrast imaging reviewed together served as the reference standard.
  
  
  RESULTS
  The overall sensitivity was 88% for the first reader and 90% for the second; specificity was 94% and 91%; positive predictive value was 96% and 94%; negative predictive value was 82% and 84%; accuracy of pre-contrast imaging for lesion detection as compared to the reference standard was 90% for both readers. The difference between mean number of lesions detected on pre-contrast imaging and reference standard was not significant for either reader (reader 1, P = 0.072; reader 2, P = 0.071). There was substantial agreement (kappa values of 0.76 and 0.72 for readers 1 and 2) between pre-contrast imaging and reference standard for determining solid vs. cystic lesion and likely nature of the lesion. The addition of post-contrast imaging increased confidence of both readers significantly (P < 0.0001), but the interobserver agreement for the change in confidence was poor (kappa 0.12).
  
  
  CONCLUSIONS
  Pre-contrast abdominal MR imaging has high accuracy in lesion detection in pediatric oncology patients and shows substantial agreement with the reference standard for characterization of lesions. Gadolinium-based contrast media administration cannot be completely eliminated but can be avoided in many cases, with the decision made on a case-by-case basis, taking into consideration location and type of tumor.
authors.affiliation: Department of Diagnostic Imaging, The Hospital for Sick Children and Medical Imaging, University of Toronto, 555 University Ave., Toronto, ON, M5G 1X8, Canada.|Department of Radiology, Universiti Kebangsaan Malaysia Medical Center, Kuala Lumpur, Malaysia.
authors.forename: Faizah
authors.initials: F
authors.lastname: Mohd Zaki
authors.affiliation: Department of Family and Community Medicine, University of Toronto, Toronto, ON, Canada.
authors.forename: Rahim
authors.initials: R
authors.lastname: Moineddin
authors.affiliation: Department of Hematology and Oncology, The Hospital for Sick Children and Medical Imaging, University of Toronto, Toronto, ON, Canada.
authors.forename: Ronald
authors.initials: R
authors.lastname: Grant
authors.affiliation: Department of Diagnostic Imaging, The Hospital for Sick Children and Medical Imaging, University of Toronto, 555 University Ave., Toronto, ON, M5G 1X8, Canada. drgovindchavhan@yahoo.com.
authors.forename: Govind B
authors.initials: GB
authors.lastname: Chavhan
mesh_terms: D000005:Abdomen / Q000000981:diagnostic imaging; D000008:Abdominal Neoplasms / Q000000981:diagnostic imaging*; D002648:Child; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
keywords: Abdomen; Children; Contrast medium; Gadolinium; Magnetic resonance imaging; Oncology