title: Detection of liver metastases in patients with adenocarcinomas of the gastrointestinal tract: comparison of (18)F-FDG PET/CT and MR imaging.
abstract: OBJECTIVE
  Aim of our study was to compare the diagnostic performance of (18)F-FDG PET/CT and MR imaging (MRI) in the detection of liver metastases in patients with adenocarcinomas of the gastrointestinal tract.
  
  
  METHODS
  A total of 49 patients with adenocarcinomas of the gastrointestinal tract who had undergone (18)F-FDG PET/CT and MRI of the liver were included in this study. The MRI protocol included diffusion-weighted imaging and dynamic contrast-enhanced MR imaging after intravenous injection of Gd-DTPA. PET and MR images were analyzed by two experienced radiologists. Imaging results were correlated with histopathological findings or imaging follow-up as available. Sensitivities of both modalities were compared using McNemar Test. Receiver operating characteristic (ROC) curves were calculated to determine the diagnostic performance in correctly identifying liver metastases.
  
  
  RESULTS
  A total of 151 metastases were confirmed. For lesion detection, MRI was significantly superior to (18)F-FDG PET/CT. Sensitivity of MRI in detecting metastases was 86.8% for Reader 1 (R1) and 87.4% for Reader 2 (R2), of PET/CT 66.2% for R1 and 68.2% for R2. Regarding only metastases with diameters of 10 mm or less, sensitivities of MRI were 66.7% for R1 and 75.0% for R2, and were significantly higher than those of PET/CT (17.9% for R1 and 20.5% for R2). ROC analysis showed superiority for lesion classification of MRI as compared to (18)F-FDG PET/CT.
  
  
  CONCLUSIONS
  MRI is significantly superior to (18)F-FDG PET/CT in the detection and classification of liver metastases in patients with adenocarcinomas of the gastrointestinal tract, especially in the detection of small metastases.
authors.affiliation: Department of Radiology, Klinikum Rechts der Isar der Technischen Universität München, Ismaninger Strasse 22, 81675, Munich, Germany, christian.maegerlein@tum.de.
authors.forename: Christian
authors.initials: C
authors.lastname: Maegerlein
authors.forename: Alexander A
authors.initials: AA
authors.lastname: Fingerle
authors.forename: Michael
authors.initials: M
authors.lastname: Souvatzoglou
authors.forename: Ernst J
authors.initials: EJ
authors.lastname: Rummeny
authors.forename: Konstantin
authors.initials: K
authors.lastname: Holzapfel
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis* / Q000556:secondary; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D019788:Fluorodeoxyglucose F18; D005770:Gastrointestinal Neoplasms / Q000473:pathology*; D006801:Humans; D008113:Liver Neoplasms / Q000175:diagnosis* / Q000556:secondary; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18