title: Liver fibrosis: noninvasive diagnosis with double contrast material-enhanced MR imaging.
abstract: OBJECTIVE
  To retrospectively evaluate the accuracy of double contrast material-enhanced (hereafter double-enhanced) magnetic resonance (MR) imaging depiction of hepatic fibrosis, with histopathologic analysis findings as the reference standard.
  
  
  METHODS
  The institutional review board approved this HIPAA-compliant study and waived the requirement for informed consent. One hundred one patients (58 men, 43 women; mean age +/- standard deviation, 52 years +/- 10) who underwent double-enhanced MR imaging with superparamagnetic iron oxide (SPIO)-enhanced and double-enhanced spoiled gradient-echo (SPGR) sequences between 2001 and 2004 and had a reliable reference standard for the diagnosis of liver fibrosis were included. Two blinded MR radiologists retrospectively scored qualitative (reticulation, nodularity, and total scores) and quantitative (contrast-to-noise ratio between hyperintense and hypointense liver regions, coefficient of variation, and noise-corrected coefficient of variation) liver texture features on MR images in consensus. The image scores for patients with advanced (METAVIR fibrosis score >/= 3) versus those for patients with mild (METAVIR score </= 2) fibrosis were compared, and receiver operating characteristic curves were determined. Diagnostic performance values were calculated at the optimal operating point. Mann-Whitney U and unpaired Student t tests were performed.
  
  
  RESULTS
  Qualitative and quantitative image scores were significantly higher for patients with METAVIR fibrosis scores of 3 or higher than for those with scores of 2 or lower (P < .001); on SPIO-enhanced SPGR images, differences increased with increasing echo time. Diagnostic performance for detection of grade 3 or more severe fibrosis was better with the double-enhanced sequence than with the SPIO-enhanced sequences, and qualitative scores had higher diagnostic performance than quantitative scores. The sensitivity, specificity, and accuracy of qualitative scores on double-enhanced SPGR images were higher than 90%.
  
  
  CONCLUSIONS
  Advanced hepatic fibrosis can be detected by using double-enhanced MR imaging. Although diagnostic performance depended on the sequence and scoring system used, sensitivity, specificity, and accuracy values higher than 90% were achievable.
authors.affiliation: Departments of Radiology, Pathology, and Medicine, University of California, San Diego Medical Center, 200 W Arbor Dr, San Diego, CA 92103-8756, USA.
authors.forename: Diego A
authors.initials: DA
authors.lastname: Aguirre
authors.forename: Cynthia A
authors.initials: CA
authors.lastname: Behling
authors.forename: Elliot
authors.initials: E
authors.lastname: Alpert
authors.forename: Tarek I
authors.initials: TI
authors.lastname: Hassanein
authors.forename: Claude B
authors.initials: CB
authors.lastname: Sirlin
mesh_terms: D003287:Contrast Media; D003911:Dextrans; D005260:Female; D052203:Ferrosoferric Oxide; D006801:Humans; D007501:Iron; D008103:Liver Cirrhosis / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods; D058185:Magnetite Nanoparticles; D008297:Male; D008875:Middle Aged; D010087:Oxides; D015203:Reproducibility of Results; D012189:Retrospective Studies
chemical_list: D003287:Contrast Media; D003911:Dextrans; D058185:Magnetite Nanoparticles; D010087:Oxides; C097921:ferumoxtran-10; D007501:Iron; D052203:Ferrosoferric Oxide