title: Focal nodular hyperplasia and hepatic adenoma: differentiation with low-mechanical-index contrast-enhanced sonography.
abstract: OBJECTIVE
  The purpose of our study was to determine the differentiating features of focal nodular hyperplasia (FNH) and hepatic adenoma on contrast-enhanced sonography.
  
  
  METHODS
  Sixty-two patients who underwent contrast-enhanced sonography and were confirmed to have FNH (n = 43) or hepatic adenoma (n = 19) were assessed retrospectively for arterial phase enhancement, filling direction, stellate arteries, and portal phase enhancement. An algorithm was applied to these interpreted features to determine the contrast-enhanced sonography diagnosis.
  
  
  RESULTS
  All lesions were hypervascular in the arterial phase. Centrifugal filling was more common in FNH (39 and 32 of 43, 91% and 74% [reader 1 and reader 2]) than in adenoma (3 and 3 of 19, 16%). Centripetal or mixed filling was more common in adenoma (16 and 16 of 19, 84%) than in FNH (4 and 11 of 43, 9% and 26%) (p < 0.001, kappa = 0.61). Stellate arteries characterized FNH (29 and 26 of 43, 67% and 60%) but not adenoma (3 and 2 of 19, 16% and 11%) (p < 0.001, kappa = 0.36). Sustained portal phase enhancement was more common in FNH (37 and 39 of 43, 86% and 91%) than in adenoma (9 and 12 of 19, 47% and 63%) (p < 0.02, kappa = 0.79). The sensitivity, specificity, positive predictive value, and negative predictive value of sonography for diagnosing FNH were 95% and 86%, 74% and 79%, 89% and 90%, and 88% and 71%, (reader 1 and reader 2, respectively).
  
  
  CONCLUSIONS
  FNH is predicted on the basis of arterial phase centrifugal filling and stellate vascularity on contrast-enhanced sonography. Adenoma is less reliably predicted on the basis of centripetal or mixed filling without stellate vascularity. Sustained portal phase enhancement is more common in FNH than in adenoma but contributes less to the differentiation of these lesions.
authors: Department of Medical Imaging, Tornoto General Hospital, University of Tornoto, 585 University Ave., Toronto, ON M5G 2N2, Canada. taekyoung.kim@uhn.on.ca
authors: Tae Kyoung
authors: TK
authors: Kim
authors: Hyun-Jung
authors: HJ
authors: Jang
authors: Peter N
authors: PN
authors: Burns
authors: Jessica
authors: J
authors: Murphy-Lavallee
authors: Stephanie R
authors: SR
authors: Wilson
mesh_terms: D000236:Adenoma / Q000000981:diagnostic imaging*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D003287:Contrast Media; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D006965:Hyperplasia / Q000000981:diagnostic imaging; D007089:Image Enhancement / Q000379:methods*; D008099:Liver / Q000000981:diagnostic imaging* / Q000473:pathology*; D008113:Liver Neoplasms / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D012189:Retrospective Studies; D018615:Ultrasonography, Doppler, Color
chemical_list: D003287:Contrast Media