title: Comparison of gadoxetic acid-enhanced dynamic imaging and diffusion-weighted imaging for the preoperative evaluation of colorectal liver metastases.
abstract: OBJECTIVE
  To retrospectively compare the diagnostic accuracy for the detection of colorectal liver metastases between gadoxetic acid-enhanced MRI (EOB-MRI) and diffusion-weighted imaging (DWI) on 3.0 Tesla (T) system, and then to determine whether a combination of the two techniques may improve the diagnostic performance.
  
  
  METHODS
  Forty-seven patients underwent MR imaging at 3.0T, including DWI (DWI set) and dynamic and hepatobiliary phase EOB-MRI (EOB set) for the preoperative evaluation of colorectal liver metastases. All suspicious metastases were confirmed by hepatic surgery. Two blinded readers independently reviewed three different image sets, which consisted of DWI set, EOB set, and combined set. The accuracy was assessed by the area (Az) under the alternative-free response receiver operating characteristic curve, and the sensitivity and positive predictive value (PPV) were calculated.
  
  
  RESULTS
  We found a total of 78 confirmed colorectal liver metastases in 42 of 47 patients. Each reader noted higher diagnostic accuracy of combined set of EOB-MRI and DWI than DWI set and EOB set, without statistical significance. Regardless of the size of colorectal liver metastasis, each reader detected significantly more metastases on combined set than on DWI set, and PPV was significantly higher with DWI set than with EOB set or with combined set for one reader.
  
  
  CONCLUSIONS
  EOB-MRI was more useful for the detection of colorectal liver metastases, while DWI was more useful for their characterization. The combination of EOB-MRI and DWI showed significantly higher accuracy and sensitivity for the preoperative detection of small colorectal liver metastases than DWI.
authors.affiliation: Department of Diagnostic Radiology, Institute of Gastroenterology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: Woo-Suk
authors.initials: WS
authors.lastname: Chung
authors.forename: Myeong-Jin
authors.initials: MJ
authors.lastname: Kim
authors.forename: Yong Eun
authors.initials: YE
authors.lastname: Chung
authors.forename: Yeo-Eun
authors.initials: YE
authors.lastname: Kim
authors.forename: Mi-Suk
authors.initials: MS
authors.lastname: Park
authors.forename: Jin-Young
authors.initials: JY
authors.lastname: Choi
authors.forename: Ki Whang
authors.initials: KW
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000473:pathology*; D003287:Contrast Media / Q000494:pharmacology; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D019786:Gadolinium DTPA / Q000494:pharmacology*; D006801:Humans; D008113:Liver Neoplasms / Q000473:pathology* / Q000556:secondary*; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D011237:Predictive Value of Tests; D012372:ROC Curve; D015203:Reproducibility of Results
chemical_list: D003287:Contrast Media; C073590:gadolinium ethoxybenzyl DTPA; D019786:Gadolinium DTPA