title: Evaluation of diagnostic performance of whole-body simultaneous PET/MRI in pediatric lymphoma.
abstract: BACKGROUND
  Whole-body (18)F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) is the standard of care for lymphoma. Simultaneous PET/MRI (magnetic resonance imaging) is a promising new modality that combines the metabolic information of PET with superior soft-tissue resolution and functional imaging capabilities of MRI while decreasing radiation dose. There is limited information on the clinical performance of PET/MRI in the pediatric setting.
  
  
  OBJECTIVE
  This study evaluated the feasibility, dosimetry, and qualitative and quantitative diagnostic performance of simultaneous whole-body FDG-PET/MRI in children with lymphoma compared to PET/CT.
  
  
  METHODS
  Children with lymphoma undergoing standard of care FDG-PET/CT were prospectively recruited for PET/MRI performed immediately after the PET/CT. Images were evaluated for quality, lesion detection and anatomical localization of FDG uptake. Maximum and mean standardized uptake values (SUVmax/mean) of normal organs and SUVmax of the most FDG-avid lesions were measured for PET/MRI and PET/CT. Estimation of radiation exposure was calculated using specific age-related factors.
  
  
  RESULTS
  Nine PET/MRI scans were performed in eight patients (mean age: 15.3 years). The mean time interval between PET/CT and PET/MRI was 51 ± 10 min. Both the PET/CT and PET/MRI exams had good image quality and alignment with complete (9/9) concordance in response assessment. The SUVs from PET/MRI and PET/CT were highly correlated for normal organs (SUVmean r(2): 0.88, P<0.0001) and very highly for FDG-avid lesions (SUVmax r(2): 0.94, P=0.0002). PET/MRI demonstrated an average percent radiation exposure reduction of 39% ± 13% compared with PET/CT.
  
  
  CONCLUSIONS
  Simultaneous whole-body PET/MRI is clinically feasible in pediatric lymphoma. PET/MRI performance is comparable to PET/CT for lesion detection and SUV measurements. Replacement of PET/CT with PET/MRI can significantly decrease radiation dose from diagnostic imaging in children.
authors.affiliation: Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S. Kingshighway Blvd., St. Louis, MO, 63110, USA. ponisiom@mir.wustl.edu.
authors.forename: Maria Rosana
authors.initials: MR
authors.lastname: Ponisio
authors.affiliation: Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S. Kingshighway Blvd., St. Louis, MO, 63110, USA.|Department of Radiology, University of Alabama at Birmingham, 619 19th St S, JT 772, Birmingham, AL, 35249, USA.
authors.forename: Jonathan
authors.initials: J
authors.lastname: McConathy
authors.affiliation: Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S. Kingshighway Blvd., St. Louis, MO, 63110, USA.
authors.forename: Richard
authors.initials: R
authors.lastname: Laforest
authors.affiliation: Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S. Kingshighway Blvd., St. Louis, MO, 63110, USA.
authors.forename: Geetika
authors.initials: G
authors.lastname: Khanna
mesh_terms: D000293:Adolescent; D005240:Feasibility Studies; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008223:Lymphoma / Q000000981:diagnostic imaging*; D008279:Magnetic Resonance Imaging; D008297:Male; D064847:Multimodal Imaging / Q000379:methods; D000072078:Positron Emission Tomography Computed Tomography; D011446:Prospective Studies; D011829:Radiation Dosage; D019275:Radiopharmaceuticals; D051598:Whole Body Imaging
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
keywords: Children; Lymphoma; Magnetic resonance imaging; Positron emission tomography/Computed tomography; Positron emission tomography/Magnetic resonance imaging