title: Advanced ultrasonography technologies to assess the effects of radiofrequency ablation on hepatocellular carcinoma.
abstract: BACKGROUND
  Radiofrequency ablation (RFA) is a curative therapy for hepatocellular carcinoma (HCC). In RFA, ultrasonography (US) is most commonly used to guide tumor puncture, while its effects are assessed using dynamic computed tomography or magnetic resonance. The differences in modalities used for RFA and assessment of its effects complicate RFA. We developed a method for assessing the effects of RFA on HCC by combining contrast-enhanced (CE) US and real-time virtual sonography with three-dimensional US data.
  
  
  METHODS
  Before RFA, we performed a sweep scan of the target HCC nodule and the surrounding hepatic parenchyma to generate three-dimensional US data. After RFA, we synchronized multi-planar reconstruction images derived from stored three-dimensional US data with real-time US images on the same US monitor and performed CEUS and real-time virtual sonography. Using a marking function, we drew a sphere marker along the target HCC nodule contour on pre-treatment US- multi-planar reconstruction images so that the automatically synchronized sphere marker represented the original HCC nodule contour on post-treatment real-time CEUS images. Ablation was considered sufficient when an avascular area with a margin of several millimeters in all directions surrounded the sphere marker on CEUS.
  
  
  RESULTS
  This method was feasible and useful for assessing therapeutic effects in 13 consecutive patients with HCC who underwent RFA. In 2 patients who underwent multiple sessions of RFA, HCC-nodule portions requiring additional RFA were easily identified on US images.
  
  
  CONCLUSIONS
  This method using advanced US technologies will facilitate assessment of the effects of RFA on HCC.
authors.affiliation: Department of Gastroenterology, Kanazawa Medical University, Ishikawa, Japan.
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Toshikuni
authors.forename: Hisakazu
authors.initials: H
authors.lastname: Shiroeda
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Ozaki
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Matsue
authors.forename: Takahiro
authors.initials: T
authors.lastname: Minato
authors.forename: Tomoe
authors.initials: T
authors.lastname: Nomura
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Hayashi
authors.forename: Tomiyasu
authors.initials: T
authors.lastname: Arisawa
authors.forename: Mikihiro
authors.initials: M
authors.lastname: Tsutsumi
keywords: contrast-enhanced ultrasonography; hepatocellular carcinoma; radiofrequency ablation; real-time virtual sonography; three-dimensional ultrasonography