title: 18F-Fluorodeoxyglucose Positron Emission Tomography/Magnetic Resonance in Lymphoma: Comparison With 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography and With the Addition of Magnetic Resonance Diffusion-Weighted Imaging.
abstract: OBJECTIVE
  The aim of this study was to compare F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/magnetic resonance (MR) (with and without diffusion-weighted imaging [DWI]) to F-FDG PET/computed tomography (CT), with regard to the assessment of nodal and extranodal involvement, in patients with Hodgkin lymphoma and non-Hodgkin lymphoma, without restriction to FDG-avid subytpes.
  
  
  METHODS
  Patients with histologically proven lymphoma were enrolled in this prospective, institutional review board-approved study. After a single F-FDG injection, patients consecutively underwent F-FDG PET[Fraction Slash]CT and F-FDG PET/MR on the same day for staging or restaging. Three sets of images were analyzed separately: F-FDG PET/CT, F-FDG PET/MR without DWI, and F-FDG PET/MR with DWI. Region-based agreement and examination-based sensitivity and specificity were calculated for F-FDG PET/CT, F-FDG PET/MR without DWI, and F-FDG PET/MR DWI. Maximum and mean standardized uptake values (SUVmax, SUVmean) on F-FDG PET/CT and F-FDG PET/MR were compared and correlated with minimum and mean apparent diffusion coefficients (ADCmin, ADCmean).
  
  
  RESULTS
  Thirty-four patients with a total of 40 examinations were included. Examination-based sensitivities for F-FDG PET/CT, F-FDG PET/MR, and F-FDG PET/MR DWI were 82.1%, 85.7%, and 100%, respectively; specificities were 100% for all 3 techniques; and accuracies were 87.5%, 90%, and 100%, respectively. F-FDG PET/CT was false negative in 5 of 40 examinations (all with mucosa-associated lymphoid tissue lymphoma), and F-FDG PET/MR (without DWI) was false negative in 4 of 40 examinations. Region-based percentages of agreement were 99% (κ, 0.95) between F-FDG PET/MR DWI and F-FDG PET/CT, 99.2% (κ, 0.96) between F-FDG PET/MR and F-FDG PET/CT, and 99.4% (κ, 0.97) between F-FDG PET/MR DWI and F-FDG PET/MR. There was a strong correlation between F-FDG PET/CT and F-FDG PET/MR for SUVmax (r = 0.83) and SUVmean (r = 0.81) but no significant correlation between ADCmin and SUVmax (F-FDG PET/CT: r = 0.46, P = 0.65; F-FDG PET/MR: r = 0.64, P = 0.53) or between ADCmean and SUVmean (respectively, r = -0.14, P = 0.17 for the correlation with PET/CT and r = -0.14, P = 0.14 for the correlation with PET/MR).
  
  
  CONCLUSIONS
  F-FDG PET/MR and F-FDG PET/CT show a similar diagnostic performance in lymphoma patients. However, if DWI is included in the F-FDG PET/MR protocol, results surpass those of F-FDG PET/CT because of the higher sensitivity of DWI for mucosa-associated lymphoid tissue lymphomas.
authors.affiliation: From the *Department of Biomedical Imaging and Image-guided Therapy, †Department of Internal Medicine I, ‡Department of Internal Medicine III, and §Institute of Pathology, Medical University of Vienna, Vienna, Austria.
authors.forename: Chiara
authors.initials: C
authors.lastname: Giraudo
authors.forename: Markus
authors.initials: M
authors.lastname: Raderer
authors.forename: Georgios
authors.initials: G
authors.lastname: Karanikas
authors.forename: Michael
authors.initials: M
authors.lastname: Weber
authors.forename: Barbara
authors.initials: B
authors.lastname: Kiesewetter
authors.forename: Werner
authors.initials: W
authors.lastname: Dolak
authors.forename: Ingrid
authors.initials: I
authors.lastname: Simonitsch-Klupp
authors.forename: Marius E
authors.initials: ME
authors.lastname: Mayerhoefer
mesh_terms: D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D019788:Fluorodeoxyglucose F18; D006689:Hodgkin Disease / Q000473:pathology*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008207:Lymphatic Metastasis / Q000473:pathology*; D008228:Lymphoma, Non-Hodgkin / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography / Q000379:methods*; D011446:Prospective Studies; D019275:Radiopharmaceuticals; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18