title: Whole-body MRI of paediatric malignant tumours: comparison with conventional oncological imaging methods.
abstract: OBJECTIVE
  To evaluate the usefulness of whole-body (WB) MRI for detecting metastases from paediatric malignant tumours in comparison with conventional oncological imaging methods.
  
  
  METHODS
  Using a 1.5-T system, a coronal short tau inversion recovery (STIR) sequence was obtained in all patients. In addition, sagittal fat-suppressed T2-weighted, sagittal STIR, or coronal fat-suppressed pre-contrast and post-contrast T1-weighted sequences were performed. Patients who underwent WB MRI and conventional oncological imaging within 15 days were enrolled in the study. In total, 58 bone scintigraphies, 26 iodine-123 (123I) meta-iodo-benzylguanidine (MIBG) scintigraphies, and 48 CT scans were available for comparison in 36 patients (median age 3.5 years; 21 boys, 15 girls) who underwent 82 WB MRI examinations. Skeletal and extraskeletal metastases were evaluated for a variety of tumour types.
  
  
  RESULTS
  Concordance rate of WB MRI between two readers was 74%. In detecting metastases, WB MRI had higher sensitivity (99%) and PPV (94%) than bone scintigraphy (26 and 76%, respectively). In detecting skeletal metastases, WB MRI revealed higher sensitivity (100%) than 123I-MIBG scintigraphy (25%) and CT (10%). In contrast, WB MRI showed lower PPV in detecting skeletal and extraskeletal metastases (8 and 57%, respectively) than 123I-MIBG scintigraphy (100%), and lower sensitivity (60%) in detecting extraskeletal metastases than CT (100%). In 2 of 11 untreated patients, tumour staging was upgraded from stage 3 to 4 according to WB MRI findings. In 3 patients, WB MRI revealed early treatment responses (<1 year) of skeletal metastases.
  
  
  CONCLUSIONS
  WB MRI can substitute for bone scintigraphy in detecting skeletal metastases of paediatric malignant tumours, and it is useful in evaluating initial tumour staging and early treatment responses. However, it still has only a complementary role in detecting extraskeletal metastases.
authors.affiliation: Radiology Department, Asan Medical Centre, 388-1 Poongnap-2dong, Seoul, 138-736, Songpa-gu, Republic of Korea. hwgoo@amc.seoul.kr
authors.forename: Hyun Woo
authors.initials: HW
authors.lastname: Goo
authors.forename: Seong Hoon
authors.initials: SH
authors.lastname: Choi
authors.forename: Thad
authors.initials: T
authors.lastname: Ghim
authors.forename: Hyung Nam
authors.initials: HN
authors.lastname: Moon
authors.forename: Jong Jin
authors.initials: JJ
authors.lastname: Seo
mesh_terms: D019797:3-Iodobenzylguanidine; D001859:Bone Neoplasms / Q000175:diagnosis / Q000473:pathology; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D007091:Image Processing, Computer-Assisted; D007223:Infant; D007457:Iodine Radioisotopes; D008223:Lymphoma / Q000175:diagnosis*; D008279:Magnetic Resonance Imaging; D008297:Male; D019042:Muscle Neoplasms / Q000175:diagnosis* / Q000556:secondary; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging / Q000473:pathology; D009447:Neuroblastoma / Q000175:diagnosis* / Q000556:secondary; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D012208:Rhabdomyosarcoma / Q000175:diagnosis* / Q000556:secondary; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed; D051598:Whole Body Imaging
chemical_list: D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals; D019797:3-Iodobenzylguanidine