title: Ultrahigh-field imaging of the biliary tract at 7 T: initial results of gadoxetic acid-enhanced magnetic resonance cholangiography.
abstract: OBJECTIVE
  The objectives of this study were to assess the feasibility of magnetic resonance cholangiography (MRC) using biliary-secreted gadoxetic acid at 7 T and to compare it with T2-weighted (w) MRC at 3 T.
  
  
  METHODS
  Ten healthy volunteers were examined on a 7-T whole-body magnetic resonance system. T2-weighted turbo-spin-echo sequence, T1-w volume-interpolated breath-hold examination (VIBE), and fast low-angle shot (FLASH) with inversion recovery (IR) were acquired in coronal orientation. For dynamic imaging, gadoxetic acid was administrated and data were collected for a period of 5 to 40 minutes after injection. The volunteers underwent subsequent T2-w respiratory-gated MRC at 3 T. For qualitative analysis, a 5-point scale was used. Contrast ratios (CRs) were calculated for quantitative assessment.
  
  
  RESULTS
  Contrast-enhanced T1-w MRC at 7 T showed a homogeneous depiction of the intrahepatic and extrahepatic biliary tract with a maximum enhancement of 20 minutes after contrast. Volume-interpolated breath-hold examination and FLASH IR provided a good image quality for the intrahepatic (VIBE, 3.60; FLASH IR, 3.67) and extrahepatic bile ducts (VIBE, 3.50; FLASH IR, 3.72). The quantitative analysis revealed high CR values for FLASH IR (intrahepatic CR, 0.41; extrahepatic CR, 0.45) because of an effective suppression of hepatic tissue and vessels. The T2-w TSE at 7 T showed only a poor image quality without diagnostic potential (intrahepatic, 2.22; extrahepatic, 1.93). Seven-tesla VIBE and FLASH revealed superiority in the depiction of the intrahepatic bile ducts, whereas 3-T MRC was superior in the delineation of the extrahepatic biliary tract.
  
  
  CONCLUSIONS
  Our results demonstrate the feasibility of contrast-enhanced imaging of the biliary ducts at 7 T.
authors.affiliation: From the *Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen; and †Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany.
authors.forename: Anja
authors.initials: A
authors.lastname: Fischer
authors.forename: Oliver
authors.initials: O
authors.lastname: Kraff
authors.forename: Stephan
authors.initials: S
authors.lastname: Orzada
authors.forename: Felix
authors.initials: F
authors.lastname: Nensa
authors.forename: Lena C
authors.initials: LC
authors.lastname: Schäfer
authors.forename: Mark E
authors.initials: ME
authors.lastname: Ladd
authors.forename: Lale
authors.initials: L
authors.lastname: Umutlu
authors.forename: Thomas C
authors.initials: TC
authors.lastname: Lauenstein
mesh_terms: D000328:Adult; D001659:Biliary Tract / Q000033:anatomy & histology*; D002758:Cholangiography / Q000379:methods*; D003287:Contrast Media / Q000008:administration & dosage; D005240:Feasibility Studies; D005260:Female; D019786:Gadolinium DTPA / Q000008:administration & dosage; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008280:Magnetics; D008297:Male; D012016:Reference Values; D055815:Young Adult
chemical_list: D003287:Contrast Media; C073590:gadolinium ethoxybenzyl DTPA; D019786:Gadolinium DTPA