title: Is integrated 18F-FDG PET/MRI superior to 18F-FDG PET/CT in the differentiation of incidental tracer uptake in the head and neck area?
abstract: OBJECTIVE
  We aimed to investigate the accuracy of 18F-fluorodeoxyglucose positron emission tomography/magnetic resonance imaging (18F-FDG PET/MRI) compared with contrast-enhanced 18F-FDG PET/computed tomography (PET/CT) for the characterization of incidental tracer uptake in examinations of the head and neck.
  
  
  METHODS
  A retrospective analysis of 81 oncologic patients who underwent contrast-enhanced 18F-FDG PET/CT and subsequent PET/MRI was performed by two readers for incidental tracer uptake. In a consensus reading, discrepancies were resolved. Each finding was either characterized as most likely benign, most likely malignant, or indeterminate. Using all available clinical information including results from histopathologic sampling and follow-up examinations, an expert reader classified each finding as benign or malignant. McNemar's test was used to compare the performance of both imaging modalities in characterizing incidental tracer uptake.
  
  
  RESULTS
  Forty-six lesions were detected by both modalities. On PET/CT, 27 lesions were classified as most likely benign, one as most likely malignant, and 18 as indeterminate; on PET/MRI, 31 lesions were classified as most likely benign, one lesion as most likely malignant, and 14 as indeterminate. Forty-three lesions were benign and one lesion was malignant according to the reference standard. In two lesions, a definite diagnosis was not possible. McNemar's test detected no differences concerning the correct classification of incidental tracer uptake between PET/CT and PET/MRI (P = 0.125).
  
  
  CONCLUSIONS
  In examinations of the head and neck area, incidental tracer uptake cannot be classified more accurately by PET/MRI than by PET/CT.
authors.affiliation: Department of Diagnostic and Interventional Radiology, Dusseldorf University School of Medicine, Dusseldorf, Germany; Departments of Diagnostic and Interventional Radiology and Neuroradiology, Duisburg-Essen University School of Medicine, Essen, Germany. benedikt.schaarschmidt@med.uni-duesseldorf.de.
authors.forename: Benedikt Michael
authors.initials: BM
authors.lastname: Schaarschmidt
authors.forename: Benedikt
authors.initials: B
authors.lastname: Gomez
authors.forename: Christian
authors.initials: C
authors.lastname: Buchbender
authors.forename: Johannes
authors.initials: J
authors.lastname: Grueneisen
authors.forename: Felix
authors.initials: F
authors.lastname: Nensa
authors.forename: Lino Morris
authors.initials: LM
authors.lastname: Sawicki
authors.forename: Verena
authors.initials: V
authors.lastname: Ruhlmann
authors.forename: Axel
authors.initials: A
authors.lastname: Wetter
authors.forename: Gerald
authors.initials: G
authors.lastname: Antoch
authors.forename: Philipp
authors.initials: P
authors.lastname: Heusch
mesh_terms: D000328:Adult; D000368:Aged; D003287:Contrast Media; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000378:metabolism*; D006257:Head / Q000000981:diagnostic imaging*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods; D009333:Neck / Q000000981:diagnostic imaging*; D000072078:Positron Emission Tomography Computed Tomography / Q000379:methods*; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals / Q000378:metabolism*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18