title: Radiofrequency ablation of hepatocellular carcinoma: predicting success using contrast-enhanced sonography.
abstract: OBJECTIVE
  This pilot study compared the utility of immediate postprocedural contrast-enhanced sonography with that of delayed enhanced sonography and CT or MRI in assessing the success of radiofrequency ablation of hepatocellular carcinoma.
  
  
  METHODS
  Twenty-two lesions (1.5-3.7 cm) were studied in 19 patients. Enhanced sonography was performed before and within 1 hr after radiofrequency ablation. At routine 2-week follow-up CT or MRI, additional enhanced sonography was performed. The findings of preablation CT or MRI and enhanced sonography were compared with those of postprocedural and follow-up enhanced sonography by three radiologists experienced in these techniques. The reviewers were unaware of the follow-up CT or MRI results (reference standard). Technical adequacy, ablation zone targeting, and identification of residual disease were assessed by each reviewer, and the results were analyzed by consensus.
  
  
  RESULTS
  One postprocedural sonographic study was considered technically inadequate. Postprocedural sonography predicted the follow-up CT or MRI results in 76% (16/21) of subjects (sensitivity, 88%; specificity, 40%; positive predictive value [PPV], 82%; negative predictive value, [NPV] 50%). Follow-up CT or MRI identified accurate targeting in 17 of 22 subjects. Follow-up sonography agreed with CT or MRI in 82% (18/22) of subjects (sensitivity, 88%; specificity, 67%; PPV, 88%; NPV, 67%). Postprocedural sonography predicted the follow-up CT or MRI results in 81% (17/21) of subjects (sensitivity, 40%; specificity, 94%; PPV, 66%; NPV, 83%). Follow-up CT or MRI detected residual disease in six subjects. Follow-up sonography agreed with CT or MRI in 91% (20/22) of subjects (sensitivity, 83%; specificity, 94%; PPV, 83%; NPV, 94%).
  
  
  CONCLUSIONS
  Postprocedural enhanced sonography has the potential to guide completion of radiofrequency ablation at the time of initial therapy when residual disease is detected. The procedure is less accurate in detection of residual disease than is either delayed enhanced sonography or CT or MRI.
authors.affiliation: Department of Medical Imaging, University Health Network/Mount Sinai Hospital, Toronto, Ontario, Canada. Mrcus.Dill-Macky@uhn.on.ca
authors.forename: Marcus J
authors.initials: MJ
authors.lastname: Dill-Macky
authors.forename: Murray
authors.initials: M
authors.lastname: Asch
authors.forename: Peter
authors.initials: P
authors.lastname: Burns
authors.forename: Stephanie
authors.initials: S
authors.lastname: Wilson
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006528:Carcinoma, Hepatocellular / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000601:surgery*; D017115:Catheter Ablation; D005260:Female; D006801:Humans; D008113:Liver Neoplasms / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000601:surgery*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011237:Predictive Value of Tests; D012074:Remission Induction; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography