title: Clinical impact of PET/MR imaging in patients with cancer undergoing same-day PET/CT: initial experience in 134 patients--a hypothesis-generating exploratory study.
abstract: OBJECTIVE
  To compare the clinical impact of combined positron emission tomography (PET) and magnetic resonance (MR) imaging to that of combined PET and computed tomography (CT) performed on the same day in patients with cancer.
  
  
  METHODS
  This HIPAA-compliant retrospective study was approved by the institutional review board. Patients gave written informed consent for study enrollment, including the possibility to use their imaging and clinical data in future evaluations. A total of 134 patients with cancer with a non-central nervous system primary neoplasm underwent same-day fluorodeoxyglucose (FDG) PET/CT and FDG PET/MR imaging. PET/CT and PET/MR studies were independently interpreted by teams of radiologists and nuclear medicine physicians. Four readers, divided into two teams composed of one radiologist and one nuclear medicine physician each, read all 134 studies. The referring physician classified discordance between PET/CT and PET/MR observations either as findings affecting clinical management or as findings not affecting clinical management. Data were compared with the χ(2) test.
  
  
  RESULTS
  Findings affecting clinical management were noted for PET/CT studies but not for PET/MR studies in two (1.5%) of 134 patients and for PET/MR studies but not for PET/CT studies in 24 (17.9%) of 134 patients. The discrepancies between findings affecting clinical management detected with PET/MR imaging over those detected with PET/CT were significant (P < .001).
  
  
  CONCLUSIONS
  In these patients, PET/MR imaging alone contributed to clinical management more often than did PET/CT alone. PET/MR imaging provides information that affects the care of patients with cancer and is unavailable from PET/CT. Online supplemental material is available for this article.
authors.affiliation: From the Departments of Radiology (O.A.C.) and Nuclear Medicine (E.N., A.S.), SDN Istituto Ricerca Diagnostica Nucleare, Via Gianturco 113, Naples 80143, Italy; Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging (B.R.R., A.R.G., M.G.V.), and Biostatistics Center (M.G.V.), Massachusetts General Hospital, Harvard University Medical School, Charlestown, Mass; Department of Radiology, Massachusetts General Hospital, Harvard University Medical School, Boston, Mass (D.V.S., P.F.H.); and Department of Radiology, University of Naples Federico II, Naples, Italy (M.S.).
authors.forename: Onofrio A
authors.initials: OA
authors.lastname: Catalano
authors.forename: Bruce R
authors.initials: BR
authors.lastname: Rosen
authors.forename: Dushyant V
authors.initials: DV
authors.lastname: Sahani
authors.forename: Peter F
authors.initials: PF
authors.lastname: Hahn
authors.forename: Alexander R
authors.initials: AR
authors.lastname: Guimaraes
authors.forename: Mark G
authors.initials: MG
authors.lastname: Vangel
authors.forename: Emanuele
authors.initials: E
authors.lastname: Nicolai
authors.forename: Andrea
authors.initials: A
authors.lastname: Soricelli
authors.forename: Marco
authors.initials: M
authors.lastname: Salvatore
mesh_terms: D003287:Contrast Media; D005260:Female; D019788:Fluorodeoxyglucose F18; D019786:Gadolinium DTPA; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D009367:Neoplasm Staging; D009369:Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology*; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed
chemical_list: D003287:Contrast Media; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D019786:Gadolinium DTPA