Is contrast-enhanced US alternative to spiral CT in the assessment of treatment outcome of radiofrequency ablation in hepatocellular carcinoma?
OBJECTIVE
The present study was conducted to assess the efficacy of contrast-enhanced ultrasound with low mechanical index in evaluating the response of percutaneous radiofrequency ablation treatment of hepatocellular carcinoma by comparing it with 4-row spiral computed tomography.


METHODS
100 consecutive patients (65 men and 35 women; age range: 62 - 76 years) with solitary hepatocellular carcinomas (mean lesion diameter: 3.7 cm +/- 1.1 cm SD) underwent internally cooled radiofrequency ablation. Therapeutic response was evaluated at one month after the treatment with triple-phasic contrast-enhanced spiral CT and low-mechanical index contrast-enhanced ultrasound following bolus injection of 2.4 ml of Sonovue (Bracco, Milan). 60 out of 100 patients were followed up for another 3 months. Contrast-enhanced sonographic studies were reviewed by two blinded radiologists in consensus. Sensitivity, specificity, NPV and PPV of contrast-enhanced ultrasound examination were determined.


RESULTS
After treatment, contrast-enhanced ultrasound identified persistent signal enhancement in 24 patients (24 %), whereas no intratumoral enhancement was detected in the remaining 76 patients (76 %). Using CT imaging as gold standard, the sensitivity, specificity, NPV, and PPV of contrast enhanced ultrasound were 92.3 % (95 % CI = 75.9 - 97.9 %), 100 % (95 % CI = 95.2 - 100 %), 97.4 % (95 % CI = 91.1 - 99.3 %), and 100 % (95 % CI = 86.2 - 100 %).


CONCLUSIONS
Contrast-enhanced ultrasound with low mechanical index using Sonovue is a feasible tool in evaluating the response of hepatocellular carcinoma to radiofrequency ablation. Accuracy is comparable to 4-row spiral CT.
Ricci
P
P
Department of Radiology, University La Sapienza, Rome, Italy.
Cantisani
V
V
Drudi
F
F
Pagliara
E
E
Bezzi
M
M
Meloni
F
F
Calliada
F
F
Erturk
S M
SM
D'Andrea
V
V
D'Ambrosio
U
U
Passariello
R
R
D000368:Aged; D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging* / Q000601:surgery*; D017115:Catheter Ablation; D003287:Contrast Media / Q000008:administration & dosage*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D018365:Neoplasm, Residual / Q000000981:diagnostic imaging / Q000601:surgery; D010743:Phospholipids; D011183:Postoperative Complications / Q000000981:diagnostic imaging; D012086:Reoperation; D013459:Sulfur Hexafluoride; D025321:Surgery, Computer-Assisted; D036542:Tomography, Spiral Computed; D014463:Ultrasonography / Q000379:methods*
D003287:Contrast Media; D010743:Phospholipids; C420843:contrast agent BR1; D013459:Sulfur Hexafluoride