title: What is the best time to evaluate treatment response after radiofrequency ablation of hepatocellular carcinoma using contrast-enhanced sonography?
abstract: OBJECTIVE
  To observe the visibility and changes in the echogenicity of ablated tumor and ablated nontumor areas after radiofrequency ablation (RFA) over time using gray-scale sonography, and, consequently, to decide on the best timing for contrast-enhanced sonography to evaluate the response of hepatocellular carcinoma to RFA.
  
  
  METHODS
  Thirty-eight patients with 48 hepatocellular carcinoma nodules underwent RFA. Consecutive gray-scale sonographic observations were made 10 min before RFA and at five points within 4 days after RFA. Two hepatologists blindly reviewed the sonographic images to assess the identifiability of the boundary of the ablated nodules and to semiquantitatively score the echogenicity of the ablated tumor and ablated nontumor regions in 15 hypoechoic nodules with detectable boundaries within 4 days after RFA.
  
  
  RESULTS
  The detection rates of the boundaries of ablated tumors were 56.5, 65.2, 54.3, 43.5, and 39.1% at 3-6 h and 15-22 h and on the 3rd, 4th, and 5th days after RFA. There was a significant difference between the detection rate for ablated tumors at 15-22 h and that on the 3rd and 4th days. The difference in echogenicity between ablated tumor and ablated nontumor tissue reached a maximum at 15-22 h after RFA.
  
  
  CONCLUSIONS
  Ablated tumor can be clearly identified within the ablated area in 65.2% of cases using gray-scale sonography at 15-22 h after RFA. The day following RFA is most appropriate and practical for the performance of contrast-enhanced sonography to evaluate the therapeutic response, including a safety margin.
authors: Department of Ultrasound, Wuhan General Hospital of the Guangzhou Military Area, Wuhan, PR China.
authors: Pei
authors: P
authors: Zhou
authors: Masatoshi
authors: M
authors: Kudo
authors: Yasunori
authors: Y
authors: Minami
authors: Hobyung
authors: H
authors: Chung
authors: Tatsuo
authors: T
authors: Inoue
authors: Toyokazu
authors: T
authors: Fukunaga
authors: Kiyoshi
authors: K
authors: Maekawa
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000601:surgery; D017115:Catheter Ablation; D003287:Contrast Media; D005260:Female; D006801:Humans; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D013997:Time Factors; D016896:Treatment Outcome; D014463:Ultrasonography / Q000379:methods
chemical_list: D003287:Contrast Media