title: Ionising radiation-free whole-body MRI versus (18)F-fluorodeoxyglucose PET/CT scans for children and young adults with cancer: a prospective, non-randomised, single-centre study.
abstract: BACKGROUND
  Imaging tests are essential for staging of children with cancer. However, CT and radiotracer-based imaging procedures are associated with substantial exposure to ionising radiation and risk of secondary cancer development later in life. Our aim was to create a highly effective, clinically feasible, ionising radiation-free staging method based on whole-body diffusion-weighted MRI and the iron supplement ferumoxytol, used off-label as a contrast agent.
  
  
  METHODS
  We compared whole-body diffusion-weighted MRI with standard clinical (18)F-fluorodeoxyglucose ((18)F-FDG) PET/CT scans in children and young adults with malignant lymphomas and sarcomas. Whole-body diffusion-weighted magnetic resonance images were generated by coregistration of colour-encoded ferumoxytol-enhanced whole-body diffusion-weighted MRI scans for tumour detection with ferumoxytol-enhanced T1-weighted MRI scans for anatomical orientation, similar to the concept of integrated (18)F-FDG PET/CT scans. Tumour staging results were compared using Cohen's κ statistics. Histopathology and follow-up imaging served as the standard of reference. Data was assessed in the per-protocol population. This study is registered with ClinicalTrials.gov, number NCT01542879.
  
  
  RESULTS
  22 of 23 recruited patients were analysed because one patient discontinued before completion of the whole-body scan. Mean exposure to ionising radiation was 12·5 mSv (SD 4·1) for (18)F-FDG PET/CT compared with zero for whole-body diffusion-weighted MRI. (18)F-FDG PET/CT detected 163 of 174 malignant lesions at 1325 anatomical regions and whole-body diffusion-weighted MRI detected 158. Comparing (18)F-FDG PET/CT to whole-body diffusion-weighted MRI, sensitivities were 93·7% (95% CI 89·0-96·8) versus 90·8% (85·5-94·7); specificities 97·7% (95% CI 96·7-98·5) versus 99·5% (98·9-99·8); and diagnostic accuracies 97·2% (93·6-99·4) versus 98·3% (97·4-99·2). Tumour staging results showed very good agreement between both imaging modalities with a κ of 0·93 (0·81-1·00). No adverse events after administration of ferumoxytol were recorded.
  
  
  CONCLUSIONS
  Ferumoxytol-enhanced whole-body diffusion-weighted MRI could be an alternative to (18)F-FDG PET/CT for staging of children and young adults with cancer that is free of ionising radiation. This new imaging test might help to prevent long-term side-effects from radiographic staging procedures.
  
  
  BACKGROUND
  Thrasher Research Fund and Clinical Health Research Institute at Stanford University.
authors.affiliation: Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, CA, USA.
authors.forename: Christopher
authors.initials: C
authors.lastname: Klenk
authors.affiliation: Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, CA, USA.
authors.forename: Rakhee
authors.initials: R
authors.lastname: Gawande
authors.affiliation: Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, CA, USA.
authors.forename: Lebriz
authors.initials: L
authors.lastname: Uslu
authors.affiliation: Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, CA, USA.
authors.forename: Aman
authors.initials: A
authors.lastname: Khurana
authors.affiliation: Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, CA, USA.
authors.forename: Deqiang
authors.initials: D
authors.lastname: Qiu
authors.affiliation: Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, CA, USA.
authors.forename: Andrew
authors.initials: A
authors.lastname: Quon
authors.affiliation: Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, CA, USA.
authors.forename: Jessica
authors.initials: J
authors.lastname: Donig
authors.affiliation: Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, CA, USA.
authors.forename: Jarrett
authors.initials: J
authors.lastname: Rosenberg
authors.affiliation: Pediatric Hematology/Oncology, Stanford University, Stanford, CA, USA.
authors.forename: Sandra
authors.initials: S
authors.lastname: Luna-Fineman
authors.affiliation: Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, CA, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Moseley
authors.affiliation: Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, Stanford, CA, USA. Electronic address: heiked@stanford.edu.
authors.forename: Heike E
authors.initials: HE
authors.lastname: Daldrup-Link
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D019788:Fluorodeoxyglucose F18; D006801:Humans; D064847:Multimodal Imaging; D009369:Neoplasms / Q000175:diagnosis*; D049268:Positron-Emission Tomography / Q000379:methods*; D011446:Prospective Studies; D019275:Radiopharmaceuticals; D014057:Tomography, X-Ray Computed / Q000379:methods*; D051598:Whole Body Imaging / Q000379:methods*; D055815:Young Adult
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18