title: 18F-fluoroethylcholine (18F-Cho) PET/MRI functional parameters in pediatric astrocytic brain tumors.
abstract: OBJECTIVE
  To examine the feasibility of simultaneous acquisition of F-fluoroethylcholine (F-choline) PET and functional MRI (standardized uptake value [SUV]max/mean and apparent diffusion coefficient [ADC]mean), using a hybrid PET/MRI scanner, for diagnosis and response assessment in a cohort of children with astrocytic brain tumors.
  
  
  METHODS
  F-choline PET/MRI scans were performed in 12 patients with proven astrocytic tumors.Eight patients simultaneously underwent F-choline PET/MR follow-up scans after treatment. Uptake in the lesion above the normal brain activity was considered indicative of a positive scan. Maximum and mean SUVs (SUVmax and SUVmean) and mean ADC (ADCmean) of the whole tumor region of interest were assessed. Lesion size and contrast enhancement were recorded. For all tumors, the association between ADCmean and SUVmean/SUVmax values were assessed using the Spearman correlation coefficient.
  
  
  RESULTS
  At baseline, the areas of F-choline uptake matched areas of contrast enhancement and restricted diffusion. There was a negative correlation trend between SUVmax and ADCmean and a positive correlation trend between SUVmax and tumor size. There was concordance between reduction in tumor size and reductions in SUVmax and SUVmean in 4 children, in three of whom ADCmean values were increased. In 2 patients, tumor size remained stable whereas SUVmax and SUVmean values were increased with reduction in the ADCmean values. Additionally, in 2 children, cross-sectional MRI showed an increase both in tumor size and SUVmax but a reduction in ADC values.
  
  
  CONCLUSIONS
  Simultaneous F-choline PET/MRI is a promising and reliable imaging tool for children with astrocytic tumors, as it permits monitoring of morphological and metabolic response and changes during therapy.
authors.affiliation: From the *Department of Nuclear Medicine, and †Department of Paediatric and Adolescent Oncology, University College London Hospitals NHS Foundation Trust, London, United Kingdom; ‡Department of Paediatric Oncology, Great Ormond Street Hospital, London, UK; §Department of Radiology University, and ¶Department of Clinical Oncology, University College London Hospitals NHS Foundation Trust, London, United Kingdom.
authors.forename: Francesco
authors.initials: F
authors.lastname: Fraioli
authors.forename: Ananth
authors.initials: A
authors.lastname: Shankar
authors.forename: Darren
authors.initials: D
authors.lastname: Hargrave
authors.forename: Harpreet
authors.initials: H
authors.lastname: Hyare
authors.forename: Mark N
authors.initials: MN
authors.lastname: Gaze
authors.forename: Ashley M
authors.initials: AM
authors.lastname: Groves
authors.forename: Pierpaolo
authors.initials: P
authors.lastname: Alongi
authors.forename: Sara
authors.initials: S
authors.lastname: Stoneham
authors.forename: Sofia
authors.initials: S
authors.lastname: Michopoulou
authors.forename: Rizwan
authors.initials: R
authors.lastname: Syed
authors.forename: Jamshed B
authors.initials: JB
authors.lastname: Bomanji
mesh_terms: D000293:Adolescent; D001254:Astrocytoma / Q000000981:diagnostic imaging*; D001932:Brain Neoplasms / Q000000981:diagnostic imaging*; D002648:Child; D002794:Choline / Q000031:analogs & derivatives*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D064847:Multimodal Imaging; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D014057:Tomography, X-Ray Computed
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; C448902:fluoroethylcholine; D002794:Choline