title: Characterization of focal liver lesions (FLL) with acoustic radiation force impulse (ARFI) elastometry.
abstract: OBJECTIVE
  The technology of acoustic radiation force impulse (ARFI) represents an innovative method for the quantification of tissue elasticity. The aim of this prospective pilot study was to evaluate the role of ARFI elastometry of focal liver lesions (FLL) and the surrounding liver parenchyma.
  
  
  METHODS
  All patients with unclear FLL in B-mode ultrasound were assigned to ARFI elastometry (m/sec). Measurement sites were located within the FLL, in the peritumoral tissue and in hepatic segment VIII (intercostal approach). Histology and CEUS served as the reference for the characterization of the lesions.
  
  
  RESULTS
  A total of 81 patients were enrolled, of whom 62 patients (39 females, 23 males; mean age 54 years) had FLL measurable by means of ARFI. The lesions were: 38 benign (61 %) and 24 malignant FLL (39 %). The ARFI elastometric values of the FLL differed significantly from those of the liver parenchyma (p < 0.001). Elastometry of benign lesions and of malignant tumors showed statistically comparable results (p = 0.28). The lowest ARFI values were observed in focal fatty sparing and the highest in CCC. Only focal fatty sparing and HCC showed negative differences between FLL and peritumoral tissue or liver parenchyma. In 23 % of the hepatic lesions, no reliable quantitative ARFI results were obtainable due to false, inconsistent or technically failed measurements.
  
  
  CONCLUSIONS
  FLL vary in ARFI elastometry. However, high ARFI values occur in benign as well as in malignant lesions and do not permit differentiation between them.
authors.affiliation: Departement of Internal Medicine 1, University of Erlangen, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Heide
authors.forename: D
authors.initials: D
authors.lastname: Strobel
authors.forename: T
authors.initials: T
authors.lastname: Bernatik
authors.forename: R S
authors.initials: RS
authors.lastname: Goertz
mesh_terms: D001650:Bile Duct Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D001653:Bile Ducts, Intrahepatic / Q000000981:diagnostic imaging* / Q000473:pathology; D001706:Biopsy; D018281:Cholangiocarcinoma / Q000000981:diagnostic imaging* / Q000473:pathology; D003287:Contrast Media / Q000008:administration & dosage; D003937:Diagnosis, Differential; D054459:Elasticity Imaging Techniques / Q000379:methods*; D005260:Female; D020518:Focal Nodular Hyperplasia / Q000000981:diagnostic imaging / Q000473:pathology; D006391:Hemangioma / Q000000981:diagnostic imaging / Q000473:pathology; D006406:Hematoma / Q000000981:diagnostic imaging* / Q000473:pathology; D006801:Humans; D008099:Liver / Q000000981:diagnostic imaging / Q000473:pathology; D008103:Liver Cirrhosis / Q000000981:diagnostic imaging / Q000473:pathology; D008107:Liver Diseases / Q000000981:diagnostic imaging* / Q000473:pathology; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000556:secondary*; D008297:Male; D008875:Middle Aged; D010743:Phospholipids; D010865:Pilot Projects; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D013459:Sulfur Hexafluoride
chemical_list: D003287:Contrast Media; D010743:Phospholipids; C420843:contrast agent BR1; D013459:Sulfur Hexafluoride