title: Whole-body MRI of Langerhans cell histiocytosis: comparison with radiography and bone scintigraphy.
abstract: BACKGROUND
  In Langerhans cell histiocytosis (LCH) evaluation of the extent of disease is one of the major predictors of patient outcome. Historically this is undertaken using plain radiography and bone scintigraphy. Recently, whole-body (WB) MRI has been reported to be useful in detecting skeletal and extraskeletal metastases in both adults and children.
  
  
  OBJECTIVE
  To evaluate the usefulness of WB MRI in patients with LCH in comparison with plain radiography and bone scintigraphy.
  
  
  METHODS
  In nine children (1-7 years of age; mean 3.3 years) who had a pathological diagnosis of LCH and had either plain radiography or bone scintigraphy for comparison, 43 WB MR examinations were performed. Skeletal and extraskeletal lesions of the disease on WB MRI were compared with those on plain radiography and bone scintigraphy.
  
  
  RESULTS
  LCH showed unifocal single-system involvement in one patient, multifocal single-system involvement in three, and multifocal multisystem disease in five. WB MRI identified additional skeletal lesions in three (38%) of eight patients, compared with plain radiography, and in two (25%) of eight, compared with bone scintigraphy. WB MRI detected extraskeletal lesions of the disease in five (56%) of the nine patients exclusively, except for one patient whose lung lesions were also detected on plain radiography. In two patients, treatment was changed according to WB MRI findings.
  
  
  CONCLUSIONS
  WB MRI is a useful initial and follow-up diagnostic method to assess the extent of LCH because WB MRI not only identifies more skeletal lesions of the disease than do plain radiography and bone scintigraphy, but also detects extraskeletal lesions of the disease.
authors.affiliation: Department of Radiology, University of Ulsan College of Medicine, Asan Medical Center, 388-1 Poongnap-2 dong, Songpa-gu, Seoul, 138-736, South Korea. hwgoo@amc.seoul.kr
authors.forename: Hyun Woo
authors.initials: HW
authors.lastname: Goo
authors.forename: Dong Hyun
authors.initials: DH
authors.lastname: Yang
authors.forename: Young Shin
authors.initials: YS
authors.lastname: Ra
authors.forename: Joon Sup
authors.initials: JS
authors.lastname: Song
authors.forename: Ho Joon
authors.initials: HJ
authors.lastname: Im
authors.forename: Jong Jin
authors.initials: JJ
authors.lastname: Seo
authors.forename: Thad
authors.initials: T
authors.lastname: Ghim
authors.forename: Hyung Nam
authors.initials: HN
authors.lastname: Moon
mesh_terms: D002648:Child; D002675:Child, Preschool; D003287:Contrast Media; D005260:Female; D006646:Histiocytosis, Langerhans-Cell / Q000175:diagnosis* / Q000000981:diagnostic imaging; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D011859:Radiography; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D051598:Whole Body Imaging
chemical_list: D003287:Contrast Media; D019275:Radiopharmaceuticals