title: Combining diffusion-weighted MRI with Gd-EOB-DTPA-enhanced MRI improves the detection of colorectal liver metastases.
abstract: OBJECTIVE
  To compare the diagnostic accuracy of gadolinium-ethoxybenzyl-diethylenetriaminepentaacetic acid (Gd-EOB-DTPA)-enhanced MRI, diffusion-weighted MRI (DW-MRI) and a combination of both techniques for the detection of colorectal hepatic metastases.
  
  
  METHODS
  72 patients with suspected colorectal liver metastases underwent Gd-EOB-DTPA MRI and DW-MRI. Images were retrospectively reviewed with unenhanced T(1) and T(2) weighted images as Gd-EOB-DTPA image set, DW-MRI image set and combined image set by two independent radiologists. Each lesion detected was scored for size, location and likelihood of metastasis, and compared with surgery and follow-up imaging. Diagnostic accuracy was compared using receiver operating characteristics and interobserver agreement by kappa statistics.
  
  
  RESULTS
  417 lesions (310 metastases, 107 benign) were found in 72 patients. For both readers, diagnostic accuracy using the combined image set was higher [area under the curve (Az)=0.96, 0.97] than Gd-EOB-DTPA image set (Az=0.86, 0.89) or DW-MRI image set (Az=0.93, 0.92). Using combined image set improved identification of liver metastases compared with Gd-EOB-DTPA image set (p<0.001) or DW-MRI image set (p<0.001). There was very good interobserver agreement for lesion classification (κ=0.81-0.88).
  
  
  CONCLUSIONS
  Combining DW-MRI with Gd-EOB-DTPA-enhanced T(1) weighted MRI significantly improved the detection of colorectal liver metastases.
authors.affiliation: Department of Radiology, Royal Marsden NHS Foundation Trust, Sutton, UK. dowmukoh@icr.ac.uk
authors.forename: D-M
authors.initials: DM
authors.lastname: Koh
authors.forename: D J
authors.initials: DJ
authors.lastname: Collins
authors.forename: T
authors.initials: T
authors.lastname: Wallace
authors.forename: I
authors.initials: I
authors.lastname: Chau
authors.forename: A M
authors.initials: AM
authors.lastname: Riddell
mesh_terms: D000368:Aged; D015331:Cohort Studies; D015179:Colorectal Neoplasms / Q000473:pathology* / Q000628:therapy; D003287:Contrast Media; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008113:Liver Neoplasms / Q000175:diagnosis* / Q000556:secondary*; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging / Q000379:methods; D058996:Quality Improvement; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; C073590:gadolinium ethoxybenzyl DTPA; D019786:Gadolinium DTPA