title: Focal hepatic lesions: evaluation with contrast-enhanced gray-scale harmonic US.
abstract: OBJECTIVE
  To determine the findings of various focal hepatic lesions at contrast-enhanced gray-scale ultrasound (US) using a coded harmonic angio (CHA) technique and emphasizing lesion characterization.
  
  
  METHODS
  The study involved 95 patients with 105 focal hepatic lesions, namely 51 hepatocellular carcinomas (HCCs), 22 metastases, 22 hemangiomas, four cases of focal nodular hyperplasia (FNH), and six nontumorous nodules. After the injection of a microbubble contrast agent (SH U 508A), gray-scale harmonic US studies using a CHA technique were performed with a combination of continuous scanning to assess the intratumoral vasculature (vascular imaging) and interval-delay scanning to determine the sequential enhancement pattern (acoustic emission imaging). Each imaging pattern was categorized and analyzed.
  
  
  RESULTS
  At vascular imaging, 69% of HCCs (35/51) showed irregular branching vessels, while in 91% of metastases (20/22) a peripherally stippled pattern was observed. Intratumoral vessels were absent in 95% of hemangiomas (21/22) and all nontumorous lesions (6/6), while in 75% of FNHs (3/4) a spoke-wheel pattern was evident. At acoustic emission imaging, 71% of HCCs (36/51) showed heterogeneous enhancement and 86% (19/22) of metastases showed rim- or flame-like peripheral enhancement during the early phase, with washout occurring in all HCCs and metastases (100%, 73/73) during the late phase. In hemangiomas, enhancement was either peripheral and nodular (19/22, 86%) or persistent and homogeneous (3/22, 14%), and 75% of FNHs (3/4) became isoechoic during the late phase.
  
  
  CONCLUSIONS
  At contrast-enhanced gray-scale US using a CHA technique, a period of continuous scanning depicted the intratumoral vasculature, and interval-delay scanning demonstrated the sequential enhancement pattern. The characteristic findings of various focal hepatic lesions were thus determined.
authors.affiliation: Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Kangnam-gu, Seoul, Korea.
authors.forename: Hyun-Jung
authors.initials: HJ
authors.lastname: Jang
authors.forename: Hyo K
authors.initials: HK
authors.lastname: Lim
authors.forename: Won Jae
authors.initials: WJ
authors.lastname: Lee
authors.forename: Seong Hyun
authors.initials: SH
authors.lastname: Kim
authors.forename: Min Ju
authors.initials: MJ
authors.lastname: Kim
authors.forename: Dongil
authors.initials: D
authors.lastname: Choi
authors.forename: Soon Jin
authors.initials: SJ
authors.lastname: Lee
authors.forename: Jae Hoon
authors.initials: JH
authors.lastname: Lim
mesh_terms: D006528:Carcinoma, Hepatocellular / Q000098:blood supply / Q000000981:diagnostic imaging; D003287:Contrast Media; D005260:Female; D020518:Focal Nodular Hyperplasia / Q000000981:diagnostic imaging; D006391:Hemangioma / Q000098:blood supply / Q000000981:diagnostic imaging; D006801:Humans; D008099:Liver / Q000000981:diagnostic imaging*; D008113:Liver Neoplasms / Q000098:blood supply / Q000000981:diagnostic imaging* / Q000556:secondary; D008297:Male; D008875:Middle Aged; D011134:Polysaccharides; D014463:Ultrasonography
chemical_list: D003287:Contrast Media; D011134:Polysaccharides; C059891:SHU 508