title: Added Value of Integrated Whole-Body PET/MRI for Evaluation of Colorectal Cancer: Comparison With Contrast-Enhanced MDCT.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the added clinical value of PET/MRI compared with conventional contrast-enhanced MDCT (CECT) alone in the evaluation of patients with colorectal cancer.
  
  
  METHODS
  The study population comprised 51 patients with colorectal cancer who underwent (18)F-FDG PET/MRI and CECT within a 90-day interval between October 2012 and August 2013. Two reviewers in consensus evaluated whether PET/MRI added value to CECT for lesion detection and characterization and assessed whether changes in treatment strategies were made. The malignancy probability of each lesion was assessed on a 5-point scale. ROC analyses were performed with histopathologic findings, imaging, and clinical follow-up as the reference standards. Two reviewers evaluated the presence or absence of pulmonary metastatic nodules on PET/MR images that had been detected on chest CT scans.
  
  
  RESULTS
  PET/MRI added value to CECT for 14 of 51 patients (27.5%) in terms of better characterization (12/51 [23.5%]) and additional detection (2/51 [3.9%]) of extracolonic lesions. The additional information from PET/MRI led to a change in treatment strategy for 11 of 51 (21.6%) patients. ROC analyses showed that PET/MRI was significantly superior to CT in depicting colorectal cancer (p < 0.05). The rate of detection of pulmonary metastatic nodules with PET/MRI was 52.9% (9/17).
  
  
  CONCLUSIONS
  Integrated whole-body PET/MRI added value to CECT in the detection of metastatic lesions and characterization of indeterminate lesions, albeit with limited performance for small pulmonary metastatic nodules. The results suggest that PET/MRI may aid in the selection of more appropriate treatment strategies for patients with colorectal cancer.
authors.affiliation: 1 Department of Radiology, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Beomsik
authors.initials: B
authors.lastname: Kang
authors.affiliation: 1 Department of Radiology, Seoul National University College of Medicine, Seoul, Korea.|2 Institute of Radiation Medicine, Seoul National University College of Medicine, Institute of Radiation Medicine, Seoul National University College of Medicine, 101 Daehak-ro, Jongno-gu, Seoul, 110-744, Korea.
authors.forename: Jeong Min
authors.initials: JM
authors.lastname: Lee
authors.affiliation: 1 Department of Radiology, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Yong Sub
authors.initials: YS
authors.lastname: Song
authors.affiliation: 1 Department of Radiology, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Sungmin
authors.initials: S
authors.lastname: Woo
authors.affiliation: 3 Department of Radiology, SMG-SNU Boramae Medical Center, Seoul, Korea.
authors.forename: Bo Yun
authors.initials: BY
authors.lastname: Hur
authors.affiliation: 1 Department of Radiology, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Ju Hyeon
authors.initials: JH
authors.lastname: Jeon
authors.affiliation: 4 Department of Nuclear Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: Jin Chul
authors.initials: JC
authors.lastname: Paeng
mesh_terms: D000328:Adult; D000368:Aged; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000473:pathology; D003287:Contrast Media; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D061330:Multidetector Computed Tomography; D064847:Multimodal Imaging; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D051598:Whole Body Imaging
chemical_list: D003287:Contrast Media; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
keywords: MRI; PET/MRI; colorectal cancer; hybrid imaging