title: Re-appearance of power Doppler signals in the tumor nodules of hepatocellular carcinoma after transarterial embolization reflects residual viable tumor cells: histological confirmation.
abstract: OBJECTIVE
  A recent advance in ultrasonography is the use of power Doppler for detecting low-velocity angle-independent blood flow at the microvascular level. The present study was prospectively performed to elucidate the relationship between the power Doppler signals of hepatocellular carcinoma after transarterial embolization and histological confirmation of viable tumor cells.
  
  
  METHODS
  The observance of hepatocellular carcinoma-related Doppler signals in 48 patients with 67 nodules was examined after transarterial embolization, and its correlation with the presence of viable tumor cells using ultrasound-guided biopsy specimens was analyzed.
  
  
  RESULTS
  Power Doppler signals disappeared in 54 out of 67 nodules (80%) one day after transarterial embolization, but the signals re-appeared in 55-53% of the specimens at 4-7 days and 10-14 days after treatment. Viable tumor cells were histologically proven in 27 of 34 nodules (79%) presenting power Doppler signals, while only 5 of the 22 nodules (23%) negative for Doppler signals confined viable tumor cells (P<0.001). Univariate and multivariate analysis showed that the detection of power Doppler signals after transarterial embolization was related to the size of the tumor and the presence of viable tumor cells (both, P<0.001).
  
  
  CONCLUSIONS
  These results indicate that the presence of power Doppler signals may reflect the presence of viable tumor cells after transarterial embolization, leading to the need for further treatment of hepatocellular carcinoma nodules.
authors.affiliation: Department of Gastroenterology, University of Tokyo, Japan.
authors.forename: Shin'pei
authors.initials: S
authors.lastname: Sato
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Shiratori
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Imamura
authors.forename: Shun'taro
authors.initials: S
authors.lastname: Obi
authors.forename: Shuichiro
authors.initials: S
authors.lastname: Shiina
authors.forename: Masaaki
authors.initials: M
authors.lastname: Akahane
authors.forename: Kuni
authors.initials: K
authors.lastname: Ohtomo
authors.forename: Masao
authors.initials: M
authors.lastname: Omata
mesh_terms: D006528:Carcinoma, Hepatocellular / Q000098:blood supply / Q000000981:diagnostic imaging* / Q000473:pathology / Q000628:therapy; D004621:Embolization, Therapeutic; D006801:Humans; D008113:Liver Neoplasms / Q000098:blood supply / Q000000981:diagnostic imaging* / Q000473:pathology / Q000628:therapy; D015999:Multivariate Analysis; D018365:Neoplasm, Residual / Q000000981:diagnostic imaging* / Q000473:pathology; D011446:Prospective Studies; D018608:Ultrasonography, Doppler