Limits...
Radiofrequency ablation of liver cancer: early evaluation of therapeutic response with contrast-enhanced ultrasonography.

Choi D, Lim HK, Lee WJ, Kim SH, Kim MJ, Kim SK, Jang KM, Lee JY, Lim JH - Korean J Radiol (2004 Jul-Sep)

Bottom Line: The residual unablated tumor is usually depicted on contrast-enhanced multiphase helical computed tomography (CT) as a focal enhancing structure during the arterial and portal venous phases.Contrast-enhanced color Doppler and power Doppler ultrasonography (US) have also been used to detect residual tumors.Based on our experience and reports in the literature, we consider that contrast-enhanced gray-scale harmonic US constitutes a reliable alternative to contrast-enhanced multiphase CT for the early evaluation of the therapeutic response to RF ablation for liver cancer.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Kangnam-gu, Seoul, Korea. hklim@smc.samsung.co.kr

ABSTRACT
The early assessment of the therapeutic response after percutaneous radiofrequency (RF) ablation is important, in order to correctly decide whether further treatment is necessary. The residual unablated tumor is usually depicted on contrast-enhanced multiphase helical computed tomography (CT) as a focal enhancing structure during the arterial and portal venous phases. Contrast-enhanced color Doppler and power Doppler ultrasonography (US) have also been used to detect residual tumors. Contrast-enhanced gray-scale US, using a harmonic technology which has recently been introduced, allows for the detection of residual tumors after ablation, without any of the blooming or motion artifacts usually seen on contrast-enhanced color or power Doppler US. Based on our experience and reports in the literature, we consider that contrast-enhanced gray-scale harmonic US constitutes a reliable alternative to contrast-enhanced multiphase CT for the early evaluation of the therapeutic response to RF ablation for liver cancer. This technique was also useful in targeting any residual unablated tumors encountered during additional ablation.

Show MeSH

Related in: MedlinePlus

A 70-year-old-man with hepatocellular carcinoma.A. US shows the active tip of the radiofrequency electrode (between electronic calipers) within the index tumor (arrows).B. US obtained immediately after radiofrequency ablation shows hyperechogenicity (arrows) in the ablation zone.C, D. Immediately after radiofrequency ablation, contrast-enhanced agent detection imaging obtained at 30 and 90 sec-delay show that hyperechogenicity in the ablation zone (arrows) makes it difficult to depict any residual tumor.E. The hyperechogenicity (arrows) has persisted 20 minutes after radiofrequency ablation.F. On contrast-enhanced agent detection imaging 20 minutes after radiofrequency ablation, it is not easy to evaluate the therapeutic efficacy.G. The following morning, 18 hours after radiofrequency ablation, the hyperechogenicity is no longer seen in the ablation zone.H. Acoustic emission imaging with a rapid sweeping technique at 80 sec-delay shows no vascularity within the ablation zone (arrows).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC2698161&req=5

Figure 10: A 70-year-old-man with hepatocellular carcinoma.A. US shows the active tip of the radiofrequency electrode (between electronic calipers) within the index tumor (arrows).B. US obtained immediately after radiofrequency ablation shows hyperechogenicity (arrows) in the ablation zone.C, D. Immediately after radiofrequency ablation, contrast-enhanced agent detection imaging obtained at 30 and 90 sec-delay show that hyperechogenicity in the ablation zone (arrows) makes it difficult to depict any residual tumor.E. The hyperechogenicity (arrows) has persisted 20 minutes after radiofrequency ablation.F. On contrast-enhanced agent detection imaging 20 minutes after radiofrequency ablation, it is not easy to evaluate the therapeutic efficacy.G. The following morning, 18 hours after radiofrequency ablation, the hyperechogenicity is no longer seen in the ablation zone.H. Acoustic emission imaging with a rapid sweeping technique at 80 sec-delay shows no vascularity within the ablation zone (arrows).

Mentions: After RF ablation of liver cancer, it is very difficult to detect residual unablated tumors using conventional color Doppler or power Doppler US, because the internal blood flows of the patients are slow and the signals are weak. As previously described, contrast-enhanced US can improve the detection of residual tumors in the ablation zone. During and immediately after RF ablation, hyperechogenicity in the ablation zone caused by microbubbles produced by the ablation procedure is almost always observed, which makes it difficult to obtain an accurate assessment of the therapeutic efficacy in the treated lesion (Fig. 10) (9, 22). Thus, most physicians usually wait until this hyperechogenicity disappears from the ablation zone before performing contrast-enhanced harmonic US. This transient hyperechoic zone persists for a long period of time, which has been reported to range from 15 minutes to 6 hours (9, 22). It is difficult for physicians to wait for such a long period of time with the patient on the table, because of the inconvenience to the patient and the busy schedule in the US suite.


Radiofrequency ablation of liver cancer: early evaluation of therapeutic response with contrast-enhanced ultrasonography.

Choi D, Lim HK, Lee WJ, Kim SH, Kim MJ, Kim SK, Jang KM, Lee JY, Lim JH - Korean J Radiol (2004 Jul-Sep)

A 70-year-old-man with hepatocellular carcinoma.A. US shows the active tip of the radiofrequency electrode (between electronic calipers) within the index tumor (arrows).B. US obtained immediately after radiofrequency ablation shows hyperechogenicity (arrows) in the ablation zone.C, D. Immediately after radiofrequency ablation, contrast-enhanced agent detection imaging obtained at 30 and 90 sec-delay show that hyperechogenicity in the ablation zone (arrows) makes it difficult to depict any residual tumor.E. The hyperechogenicity (arrows) has persisted 20 minutes after radiofrequency ablation.F. On contrast-enhanced agent detection imaging 20 minutes after radiofrequency ablation, it is not easy to evaluate the therapeutic efficacy.G. The following morning, 18 hours after radiofrequency ablation, the hyperechogenicity is no longer seen in the ablation zone.H. Acoustic emission imaging with a rapid sweeping technique at 80 sec-delay shows no vascularity within the ablation zone (arrows).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2698161&req=5

Figure 10: A 70-year-old-man with hepatocellular carcinoma.A. US shows the active tip of the radiofrequency electrode (between electronic calipers) within the index tumor (arrows).B. US obtained immediately after radiofrequency ablation shows hyperechogenicity (arrows) in the ablation zone.C, D. Immediately after radiofrequency ablation, contrast-enhanced agent detection imaging obtained at 30 and 90 sec-delay show that hyperechogenicity in the ablation zone (arrows) makes it difficult to depict any residual tumor.E. The hyperechogenicity (arrows) has persisted 20 minutes after radiofrequency ablation.F. On contrast-enhanced agent detection imaging 20 minutes after radiofrequency ablation, it is not easy to evaluate the therapeutic efficacy.G. The following morning, 18 hours after radiofrequency ablation, the hyperechogenicity is no longer seen in the ablation zone.H. Acoustic emission imaging with a rapid sweeping technique at 80 sec-delay shows no vascularity within the ablation zone (arrows).
Mentions: After RF ablation of liver cancer, it is very difficult to detect residual unablated tumors using conventional color Doppler or power Doppler US, because the internal blood flows of the patients are slow and the signals are weak. As previously described, contrast-enhanced US can improve the detection of residual tumors in the ablation zone. During and immediately after RF ablation, hyperechogenicity in the ablation zone caused by microbubbles produced by the ablation procedure is almost always observed, which makes it difficult to obtain an accurate assessment of the therapeutic efficacy in the treated lesion (Fig. 10) (9, 22). Thus, most physicians usually wait until this hyperechogenicity disappears from the ablation zone before performing contrast-enhanced harmonic US. This transient hyperechoic zone persists for a long period of time, which has been reported to range from 15 minutes to 6 hours (9, 22). It is difficult for physicians to wait for such a long period of time with the patient on the table, because of the inconvenience to the patient and the busy schedule in the US suite.

Bottom Line: The residual unablated tumor is usually depicted on contrast-enhanced multiphase helical computed tomography (CT) as a focal enhancing structure during the arterial and portal venous phases.Contrast-enhanced color Doppler and power Doppler ultrasonography (US) have also been used to detect residual tumors.Based on our experience and reports in the literature, we consider that contrast-enhanced gray-scale harmonic US constitutes a reliable alternative to contrast-enhanced multiphase CT for the early evaluation of the therapeutic response to RF ablation for liver cancer.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Kangnam-gu, Seoul, Korea. hklim@smc.samsung.co.kr

ABSTRACT
The early assessment of the therapeutic response after percutaneous radiofrequency (RF) ablation is important, in order to correctly decide whether further treatment is necessary. The residual unablated tumor is usually depicted on contrast-enhanced multiphase helical computed tomography (CT) as a focal enhancing structure during the arterial and portal venous phases. Contrast-enhanced color Doppler and power Doppler ultrasonography (US) have also been used to detect residual tumors. Contrast-enhanced gray-scale US, using a harmonic technology which has recently been introduced, allows for the detection of residual tumors after ablation, without any of the blooming or motion artifacts usually seen on contrast-enhanced color or power Doppler US. Based on our experience and reports in the literature, we consider that contrast-enhanced gray-scale harmonic US constitutes a reliable alternative to contrast-enhanced multiphase CT for the early evaluation of the therapeutic response to RF ablation for liver cancer. This technique was also useful in targeting any residual unablated tumors encountered during additional ablation.

Show MeSH
Related in: MedlinePlus