title: Paradoxical uptake of Gd-EOB-DTPA on the hepatobiliary phase in the evaluation of hepatic metastasis from breast cancer: is the "target sign" a common finding?
abstract: OBJECTIVE
  The purpose was to describe magnetic resonance imaging (MRI) findings of breast cancer liver metastasis using gadoxetic acid (Gd-EOB-DTPA) with an emphasis on the added value of the hepatobiliary phase (HBP).
  
  
  METHODS
  Nine patients with 13 liver metastases were included in the study after the medical records of 29 breast cancer patients who underwent Gd-EOB-DTPA-enhanced MRI between February 2008 and June 2010 were reviewed. The diagnoses of liver metastasis were established by percutaneous liver biopsy or surgery and on the basis of image findings. Two radiologists retrospectively evaluated signal intensity (SI) and sizes of metastases and patterns of enhancement in an HBP. The SI ratio was calculated as the SI of the central hyperintense portion in "target" lesions divided by the SI of nearby normal liver parenchyma on the HBP. We also measured apparent diffusion coefficient (ADC) values from Diffusion Weighted Image (DWI).
  
  
  RESULTS
  Liver metastases were all hypointense [n=13/13 (100%)] on T1-weighted imaging (WI), and many lesions had a "target" appearance with a central high SI and a peripheral low SI rim (47%) on T2WI. Dynamic study showed rim enhancement on the arterial phase (85%) and a "target" appearance, consisting of a central enhancing portion with peripheral washout or hypointense rim, on the HBP (62%). The mean SI ratio was 0.7. The mean ADC value of "target" appearing metastases was 1.25 (×10(-3) mm(2)/s; range 1.3-1.6) compared with a mean value of 0.8 (×10(-3) mm(2)/s; range 0.8-1.4) in homogeneous defect on the HBP. There was statistically significant difference (P<.05).
  
  
  CONCLUSIONS
  Breast cancer liver metastases commonly demonstrated as a peripheral ring enhancement on arterial dominant phase and a target sign with a central round enhancing portion and a peripheral hypointense rim on the HBP.
authors.affiliation: Department of Radiology, Korea University Guro Hospital, Korea University College of Medicine, 80, Guro-dong, Guro-gu, Seoul 152-703, South Korea.
authors.forename: Sumin
authors.initials: S
authors.lastname: Ha
authors.forename: Chang Hee
authors.initials: CH
authors.lastname: Lee
authors.forename: Baek Hui
authors.initials: BH
authors.lastname: Kim
authors.forename: Yang Shin
authors.initials: YS
authors.lastname: Park
authors.forename: Jongmee
authors.initials: J
authors.lastname: Lee
authors.forename: Jae Woong
authors.initials: JW
authors.lastname: Choi
authors.forename: Kyeong Ah
authors.initials: KA
authors.lastname: Kim
authors.forename: Cheol Min
authors.initials: CM
authors.lastname: Park
mesh_terms: D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology; D002277:Carcinoma / Q000378:metabolism* / Q000473:pathology / Q000556:secondary*; D005260:Female; D019786:Gadolinium DTPA / Q000493:pharmacokinetics*; D006801:Humans; D008113:Liver Neoplasms / Q000378:metabolism* / Q000473:pathology / Q000556:secondary*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014018:Tissue Distribution
chemical_list: C073590:gadolinium ethoxybenzyl DTPA; D019786:Gadolinium DTPA