Therapeutic response assessment of percutaneous radiofrequency ablation for hepatocellular carcinoma: utility of contrast-enhanced agent detection imaging.
OBJECTIVE
To assess the utility of contrast-enhanced agent detection imaging (ADI) in the assessment of the therapeutic response to percutaneous radiofrequency (RF) ablation in patients with hepatocellular carcinoma (HCC).


METHODS
Ninety patients with a total of 97 nodular HCCs (mean, 2.1+/-1.3 cm; range, 1.0-5.0 cm) treated with percutaneous RF ablation under the ultrasound guidance were evaluated with contrast-enhanced ADI after receiving an intravenous bolus injection of a microbubble contrast agent (SH U 508A). We obtained serial contrast-enhanced ADI images during the time period from 15 to 90 s after the initiation of the bolus contrast injection. All of the patients underwent a follow-up four-phase helical CT at 1 month after RF ablation, which was then repeated at 2-4 month intervals during a period of at least 12 months. The results of the contrast-enhanced ADI were compared with those of the follow-up CT in terms of the presence or absence of residual unablated tumor and local tumor progression in the treated lesions.


RESULTS
On contrast-enhanced ADI, technical success was obtained in 94 (97%) of the 97 HCCs, while residual unablated tumors were found in three HCCs (3%). Two of the three tumors that were suspicious (was not proven) for incomplete ablation were subjected to additional RF ablation. The remaining one enhancing lesion that was suspicious of a residual tumor on contrast-enhanced ADI was revealed to be reactive hyperemia at the 1-month follow-up CT. Therefore; the diagnostic concordance between the contrast-enhanced ADI and 1-month follow-up CT was 99%. Of the 94 ablated HCCs without residual tumors on both the contrast-enhanced ADI and 1-month follow-up CT after the initial RF ablation, five (5%) had CT findings of local tumor progression at a subsequent follow-up CT.


CONCLUSIONS
Despite its limitations in predicting local tumor progression in the treated tumors, contrast-enhanced ADI is potentially useful for evaluating the early therapeutic effect of percutaneous RF ablation for HCCs.
Kim
Chan Kyo
CK
Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Ilwon-dong, Kangnam-gu, Seoul 135-710, South Korea.
Choi
Dongil
D
Lim
Hyo K
HK
Kim
Seung Hoon
SH
Lee
Won Jae
WJ
Kim
Min Ju
MJ
Lee
Ji Yeon
JY
Jeon
Yong Hwan
YH
Lee
Jongmee
J
Lee
Soon Jin
SJ
Lim
Jae Hoon
JH
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006528:Carcinoma, Hepatocellular / Q000175:diagnosis / Q000601:surgery*; D017115:Catheter Ablation / Q000379:methods*; D003287:Contrast Media / Q000008:administration & dosage*; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D008099:Liver / Q000000981:diagnostic imaging*; D008113:Liver Neoplasms / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011134:Polysaccharides; D011237:Predictive Value of Tests; D011379:Prognosis; D036542:Tomography, Spiral Computed / Q000379:methods; D016896:Treatment Outcome; D018615:Ultrasonography, Doppler, Color / Q000379:methods*
D003287:Contrast Media; D011134:Polysaccharides; C059891:SHU 508