title: Focal hepatic lesions: contrast-enhancement patterns at pulse-inversion harmonic US using a microbubble contrast agent.
abstract: OBJECTIVE
  To analyze the contrast-enhancement patterns obtained at pulse-inversion harmonic imaging (PIHI) of focal hepatic lesions, and to thus determine tumor vascularity and the acoustic emission effect.
  
  
  METHODS
  We reviewed pulse-inversion images in 90 consecutive patients with focal hepatic lesions, namely hepatocellular carcinoma (HCC) (n=43), metastases (n=30), and hemangioma (n=17). Vascular and delayed phase images were obtained immediately and five minutes following the injection of a microbubble contrast agent. Tumoral vascularity at vascular phase imaging and the acoustic emission effect at delayed phase imaging were each classified as one of four patterns.
  
  
  RESULTS
  Vascular phase images depicted internal vessels in 93% of HCCs, marginal vessels in 83% of metastases, and peripheral nodular enhancement in 71% of hemangiomas. Delayed phase images showed inhomogeneous enhancement in 86% of HCCs; hypoechoic, decreased enhancement in 93% of metastases; and hypoechoic and reversed echogenicity in 65% of hemangiomas. Vascular and delayed phase enhancement patterns were associated with a specificity of 91% or greater, and 92% or greater, respectively, and with positive predictive values of 71% or greater, and 85% or greater, respectively.
  
  
  CONCLUSIONS
  Contrast-enhancement patterns depicting tumoral vascularity and the acoustic emission effect at PIHI can help differentiate focal hepatic lesions.
authors.affiliation: Department of Radiology and Institute of Medical Science, Wonkwang University School of Medicine, Jeonbuk, Korea. yoonkh@wmc.wonkwang.ac.kr
authors.forename: Eun-A
authors.initials: EA
authors.lastname: Kim
authors.forename: Kwon-Ha
authors.initials: KH
authors.lastname: Yoon
authors.forename: Young Hwan
authors.initials: YH
authors.lastname: Lee
authors.forename: Hye Won
authors.initials: HW
authors.lastname: Kim
authors.forename: Seon Kwan
authors.initials: SK
authors.lastname: Juhng
authors.forename: Jong Jin
authors.initials: JJ
authors.lastname: Won
mesh_terms: D000328:Adult; D000368:Aged; D006528:Carcinoma, Hepatocellular / Q000098:blood supply / Q000000981:diagnostic imaging*; D003106:Colon / Q000473:pathology; D003287:Contrast Media / Q000008:administration & dosage*; D003937:Diagnosis, Differential; D005260:Female; D006391:Hemangioma / Q000098:blood supply / Q000000981:diagnostic imaging*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008099:Liver / Q000000981:diagnostic imaging / Q000473:pathology; D008113:Liver Neoplasms / Q000098:blood supply / Q000000981:diagnostic imaging* / Q000556:secondary; D008168:Lung / Q000473:pathology; D008297:Male; D045423:Microbubbles; D008875:Middle Aged; D010179:Pancreas / Q000473:pathology; D011134:Polysaccharides / Q000008:administration & dosage; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013270:Stomach / Q000473:pathology; D014463:Ultrasonography
chemical_list: D003287:Contrast Media; D011134:Polysaccharides; C059891:SHU 508