title: Oncological whole-body staging in integrated (18)F-FDG PET/MR: Value of different MR sequences for simultaneous PET and MR reading.
abstract: OBJECTIVE
  To evaluate different magnetic resonance (MR) imaging sequences in integrated positron emission tomography (PET)/MR concerning their ability to detect tumors and allocate increased radionuclide uptake on (18)F-fluorodeoxyglucose ((18)F-FDG) PET in intraindividual comparison with computed tomography (CT) from PET/CT.
  
  
  METHODS
  Sixty-one patients (34 female, 27 male, mean age 57.6 y) who were examined with contrast-enhanced PET/CT and subsequent PET/MR (mean delay for PET/MR after injection: 147 ± 43 min) were included. A maximum of ten (18)F-FDG-avid lesions per patient were analyzed on CT from PET/CT and with the following MR sequences from PET/MR: T2, turbo inversion recovery magnitude (TIRM), non-enhanced T1, contrast-enhanced T1, and diffusion-weighted imaging (DWI). All lesions were rated using a four-point ordinal scale (scored from 0 to 3) concerning visual detectability of the lesion against the surrounding background and anatomical allocation of the PET finding. In each category (detectability and allocation), Wilcoxon rank sum tests were performed. Bonferroni-Holm correction was performed to prevent α-error accumulation.
  
  
  RESULTS
  In 225 (18)F-FDG-avid lesions (156 confirmed as malignant by radiological follow up, 69 by histopathology), visual detectability was comparably high on CT (mean: 2.5 ± 0.9), TIRM (mean: 2.5 ± 0.9), T2 (mean: 2.4 ± 0.9), and DWI (mean: 2.5 ± 1.0) and was significantly higher than on non-enhanced T1 (mean: 2.2 ± 1.0). While anatomic allocation of the PET finding was comparable with CT (mean: 2.6 ± 0.7), T2 (mean: 2.6 ± 0.7), and TIRM (mean: 2.8 ± 0.7), it was significantly higher compared to DWI (mean: 2.1 ± 1.0) and non-enhanced T1 (mean: 2.4 ± 0.8).
  
  
  CONCLUSIONS
  In conclusion, T2, TIRM, and contrast-enhanced T1 provide a high quality of lesion detectability and anatomical allocation of FDG-avid foci. Their performance is at least comparable to contrast-enhanced PET/CT. Non-enhanced T1 may be omitted and the necessity of DWI should be further investigated for specific questions, such as assessment of the liver.
authors.affiliation: Univ Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Dusseldorf, Germany; Univ Duisburg-Essen, Medical Faculty, Department of Diagnostic and Interventional Radiology and Neuroradiology, Essen, Germany. Electronic address: benedikt.schaarschmidt@med.uni-duesseldorf.de.
authors.forename: Benedikt M
authors.initials: BM
authors.lastname: Schaarschmidt
authors.affiliation: Univ Duisburg-Essen, Medical Faculty, Department of Diagnostic and Interventional Radiology and Neuroradiology, Essen, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Grueneisen
authors.affiliation: Univ Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Dusseldorf, Germany. Electronic address: Philipp.Heusch@med.uni-duesseldorf.de.
authors.forename: Philipp
authors.initials: P
authors.lastname: Heusch
authors.affiliation: Univ Duisburg-Essen, Medical Faculty, Department of Nuclear Medicine, D-45147 Essen, Germany.
authors.forename: Benedikt
authors.initials: B
authors.lastname: Gomez
authors.affiliation: Univ Duisburg-Essen, Medical Faculty, Department of Diagnostic and Interventional Radiology and Neuroradiology, Essen, Germany.
authors.forename: Karsten
authors.initials: K
authors.lastname: Beiderwellen
authors.affiliation: Univ Duisburg-Essen, Medical Faculty, Department of Nuclear Medicine, D-45147 Essen, Germany.
authors.forename: Verena
authors.initials: V
authors.lastname: Ruhlmann
authors.affiliation: Univ Duisburg-Essen, Medical Faculty, Department of Diagnostic and Interventional Radiology and Neuroradiology, Essen, Germany.
authors.forename: Lale
authors.initials: L
authors.lastname: Umutlu
authors.affiliation: Erwin L. Hahn Institute for Magnetic Resonance Imaging, University of Duisburg-Essen, Essen, Germany; High Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany.
authors.forename: Harald H
authors.initials: HH
authors.lastname: Quick
authors.affiliation: Univ Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Dusseldorf, Germany.
authors.forename: Gerald
authors.initials: G
authors.lastname: Antoch
authors.affiliation: Univ Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Dusseldorf, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Buchbender
mesh_terms: D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods*; D009369:Neoplasms / Q000175:diagnosis* / Q000473:pathology; D049268:Positron-Emission Tomography / Q000379:methods; D014057:Tomography, X-Ray Computed; D051598:Whole Body Imaging / Q000379:methods*
chemical_list: D019788:Fluorodeoxyglucose F18
keywords: DWI; MR imaging; PET/CT; PET/MR; PET/MRI