Ultrasonography-guided percutaneous radiofrequency ablation of hepatocellular carcinomas: a feasibility scoring system for planning sonography.
OBJECTIVE
This study was designed to evaluate whether a feasibility scoring system for planning sonography is a reliable predictor of a safe and complete ablation in ultrasonography (US)-guided percutaneous radiofrequency ablation (RFA) of hepatocellular carcinomas (HCCs).


METHODS
We retrospectively evaluated the therapeutic outcomes of 108 consecutive patients (M:F, 78:30; mean age, 57.4 years) with a single nodular HCC (mean diameter, 2.0 cm) treated by percutaneous RFA. All patients were assessed for the feasibility of performing an RFA at planning sonography prior to the ablation. The feasibility scoring system consisted of five categories: the safe electrode path (P); the vital organs adjacent to the RFA zone (O); tumor size (S); tumor conspicuity (C); and the heat-sink effect (H). Each category was divided into a four-point scale [1-4]. If a score of 4 in any category was determined, the patient was not considered to be a suitable candidate for percutaneous RFA. We assessed if the score of each category, safety score (P+O), and curability score (S+C+H) correlated with a safe and complete ablation using the chi-squared test and likelihood ratio test for trend.


RESULTS
The technical success rate was 100% (108/108) based on CT images obtained immediately after ablation. There was no 30-day mortality after RFA. There were major complications (one case of severe vasovagal reflex, one case of hemoperitoneum and one case of a pseudoaneurysm) in three (2.7%) patients, and minor complications (one case of a biloma, one case of subsegmental infarction and one case of abscess) in three (2.7%) patients. Post-ablation syndrome as a side effect was noted in 38 (35.1%) of 108 patients. The primary technique effectiveness rate at 1 month was 95.1% (105/108). Local tumor progression was noted in eight (7.6%) of 105 patients during the follow-up period (range, 3.0-11.5 months; median, 5.8 months; mean, 5.7 months). There was no significant single category to predict complication and local tumor progression (Fisher's exact test, p>0.05). Contrary to the safety score for the probability of complication (p>0.05), the curability score was significantly associated with the probability of local tumor progression (likelihood ratio test for trend; p=0.03).


CONCLUSIONS
The new feasibility scoring system for planning US can be used as objective criteria to predict therapeutic efficacy rather than the safety of percutaneous RFA of an HCC.
Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea. rhimhc@skku.edu
Hyunchul
H
Rhim
Dongil
D
Choi
Young-sun
YS
Kim
Hyo K
HK
Lim
Bong-Keun
BK
Choe
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006528:Carcinoma, Hepatocellular / Q000145:classification / Q000000981:diagnostic imaging* / Q000601:surgery*; D017115:Catheter Ablation / Q000009:adverse effects; D005260:Female; D006801:Humans; D008113:Liver Neoplasms / Q000145:classification / Q000000981:diagnostic imaging* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D018084:Ultrasonography, Interventional