title: Indeterminate observations (liver imaging reporting and data system category 3) on MRI in the cirrhotic liver: fate and clinical implications.
abstract: OBJECTIVE
  The purpose of this article is to retrospectively evaluate the imaging characteristics and outcomes of indeterminate observations (Liver Imaging Reporting and Data System category 3) detected on MRI in patients with cirrhosis.
  
  
  METHODS
  Sixty-nine indeterminate observations in 52 patients with cirrhosis were imaged with hepatobiliary contrast agent-enhanced MRI. Observations were evaluated retrospectively in terms of the location, size, enhancement pattern, and follow-up results. Each observation was categorized as stable or progressed observations according to serial follow-up MRI.
  
  
  RESULTS
  The mean follow-up interval was 11.2 months. Forty-six (67%) of the total observations showed arterial enhancement, and 23 (33%) observations showed isointense signal or low signal intensity on arterial phase. The indeterminate observations were classified as arterial enhancement with fade-out appearance (41 observations [59%]), arterial enhancement with washout appearance (five observations [7%]), and nonhyperenhancing observations (23 observations [33%]). Two of 69 observations (3%) were hyperintense on T2-weighted images, and four of 55 observations (7%) were hyperintense on hepatocellular phase. On the final follow-up MRI examinations, four (6%) observations proved to be probable or definite hepatocellular carcinoma, 55 (80%) remained stable, and 10 (14%) decreased in size or were no longer visible.
  
  
  CONCLUSIONS
  The most common cause of indeterminate observations on MRI is hypervascular pseudolesions that were clinically stable on follow-up imaging.
authors.affiliation: 1 Department of Radiology, Research Institute of Radiological Science, Yonsei University Health System, Seoul, Republic of Korea.
authors.forename: Jin-Young
authors.initials: JY
authors.lastname: Choi
authors.forename: Hyun Cheol
authors.initials: HC
authors.lastname: Cho
authors.forename: Mark
authors.initials: M
authors.lastname: Sun
authors.forename: Hyeon Chang
authors.initials: HC
authors.lastname: Kim
authors.forename: Claude B
authors.initials: CB
authors.lastname: Sirlin
mesh_terms: D000328:Adult; D006528:Carcinoma, Hepatocellular / Q000473:pathology; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008103:Liver Cirrhosis / Q000473:pathology*; D008113:Liver Neoplasms / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011873:Radiology Information Systems; D012189:Retrospective Studies
chemical_list: D003287:Contrast Media; C073590:gadolinium ethoxybenzyl DTPA; D019786:Gadolinium DTPA