title: Colorectal liver metastases: disappearing lesions in the era of Eovist hepatobiliary magnetic resonance imaging.
abstract: BACKGROUND
  Hepatobiliary contrast enhanced MRI is known to be the most sensitive imaging modality for detection of colorectal hepatic metastasis. To date no study has investigated the rate of disappearing lesions with gadoxetic acid MR (Eovist/Primovist), or characterized the pathologic response of lesions which disappear on gadoxetic acid MR.
  
  
  METHODS
  Retrospective review of hepatic resections for colorectal metastases between 01/2008 and 01/2014 was performed to evaluated the rate of disappearance of lesions on gadoxetic acid MR and the rate of complete pathologic response in the lesions that disappear. "Disappearing lesions" were lesions on baseline imaging that were not identifiable on pre-operative Eovist MRI. Complete pathologic response was defined as no viable tumor on pathology or by lack of recurrence within 1 year.
  
  
  RESULTS
  In 23 patients, 200 colorectal metastases were identified on baseline imaging. On pre-operative Eovist MR 77 of the 200 lesions (38.5%) were "disappearing" lesions. At surgical pathology or 1 year follow-up imaging, 42 of 77 lesions (55%) demonstrated viable tumor (21) or recurrence (21). Thirty of 77 lesions (39%) were nonviable at pathology (10) or without evidence of recurrence at 1 year (20). 5 lesions were indeterminate.
  
  
  CONCLUSIONS
  Despite disappearance on Eovist MR imaging (the most sensitive available imaging modality), 38.5% of all colorectal metastases disappeared and of those, 55% were viable.
authors.affiliation: University of Kentucky, Department of Radiology, United States. Electronic address: jwowen2@uky.edu.
authors.forename: Joseph W
authors.initials: JW
authors.lastname: Owen
authors.affiliation: Washington University, Department of Radiology, United States.
authors.forename: Kathryn J
authors.initials: KJ
authors.lastname: Fowler
authors.affiliation: Washington University, Department of Surgery, United States.
authors.forename: Maria B
authors.initials: MB
authors.lastname: Doyle
authors.affiliation: Washington University, Department of Radiology, United States.
authors.forename: Nael E
authors.initials: NE
authors.lastname: Saad
authors.affiliation: University of Rochester, Department of Surgery, United States.
authors.forename: David C
authors.initials: DC
authors.lastname: Linehan
authors.affiliation: Washington University, Department of Surgery, United States.
authors.forename: William C
authors.initials: WC
authors.lastname: Chapman
mesh_terms: D000328:Adult; D000368:Aged; D002470:Cell Survival; D017024:Chemotherapy, Adjuvant; D015179:Colorectal Neoplasms / Q000473:pathology*; D003287:Contrast Media / Q000008:administration & dosage*; D018450:Disease Progression; D018572:Disease-Free Survival; D005260:Female; D019786:Gadolinium DTPA / Q000008:administration & dosage*; D006498:Hepatectomy; D006801:Humans; D053208:Kaplan-Meier Estimate; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000556:secondary* / Q000628:therapy; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D018365:Neoplasm, Residual; D000072078:Positron Emission Tomography Computed Tomography; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012189:Retrospective Studies; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D003287:Contrast Media; C073590:gadolinium ethoxybenzyl DTPA; D019786:Gadolinium DTPA