title: Vascularity of hepatocellular carcinoma: assessment with contrast-enhanced second-harmonic versus conventional power Doppler US.
abstract: OBJECTIVE
  To compare contrast material-enhanced harmonic power Doppler ultrasonography (US) with conventional power Doppler US in depicting the vascularity of hepatocellular carcinoma (HCC).
  
  
  METHODS
  Twenty patients with nodular HCCs (2.6-13.2 cm in diameter; mean diameter, 4.8 cm) were prospectively examined with both conventional and harmonic power Doppler US. US was performed with a 2-4-MHz curved linear-array transducer according to a standard examination protocol (1,000-Hz pulse repetition frequency, medium wall filter, and power gain of 55%-84% for conventional power Doppler US; 700-Hz pulse repetition frequency, low wall filter, and power gain of 95%-98% for harmonic power Doppler US). Serial, dynamic scans were obtained before intravenous injection of the contrast agent (SH U 508A) and at 30, 60, 90, 120, 180, 240, and 300 seconds after injection with both techniques.
  
  
  RESULTS
  The number of intratumoral power Doppler US signals was similar with both techniques at 30-90 seconds after contrast agent injection; however, after 90 seconds, conventional power Doppler US depicted significantly more signals than did harmonic power Doppler US. Harmonic power Doppler US was superior to conventional power Doppler US in terms of power Doppler artifacts such as "blooming" or motion-related artifacts.
  
  
  CONCLUSIONS
  Although the effective enhancement duration is relatively short compared with that for conventional power Doppler US, contrast-enhanced harmonic power Doppler US can be effective in evaluating the vascularity of HCCs because of the advantage of fewer power Doppler artifacts.
authors.affiliation: Department of Radiology and the Institute of Radiation Medicine, Seoul National University Hospital, 28, Yongon-dong, Chongno-gu, Seoul 110-744, South Korea.
authors.forename: B I
authors.initials: BI
authors.lastname: Choi
authors.forename: T K
authors.initials: TK
authors.lastname: Kim
authors.forename: J K
authors.initials: JK
authors.lastname: Han
authors.forename: A Y
authors.initials: AY
authors.lastname: Kim
authors.forename: C K
authors.initials: CK
authors.lastname: Seong
authors.forename: S J
authors.initials: SJ
authors.lastname: Park
mesh_terms: D000368:Aged; D016477:Artifacts; D006528:Carcinoma, Hepatocellular / Q000098:blood supply* / Q000000981:diagnostic imaging; D003287:Contrast Media / Q000008:administration & dosage; D005260:Female; D005374:Filtration / Q000295:instrumentation; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007275:Injections, Intravenous; D008113:Liver Neoplasms / Q000098:blood supply* / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D011134:Polysaccharides / Q000008:administration & dosage; D011446:Prospective Studies; D013997:Time Factors; D014159:Transducers; D018608:Ultrasonography, Doppler / Q000295:instrumentation / Q000379:methods*
chemical_list: D003287:Contrast Media; D011134:Polysaccharides; C059891:SHU 508