Background. Radiofrequency ablation (RFA) is a curative therapy for hepatocellular carcinoma (HCC). In RFA, ultrasonography (US) is most commonly used to guide tumor puncture, while its effects are assessed using dynamic computed tomography or magnetic resonance. The differences in modalities used for RFA and assessment of its effects complicate RFA. We developed a method for assessing the effects of RFA on HCC by combining contrast-enhanced (CE) US and real-time virtual sonography with three-dimensional US data.
Patients and methods. Before RFA, we performed a sweep scan of the target HCC nodule and the surrounding hepatic parenchyma to generate three-dimensional US data. After RFA, we synchronized multi-planar reconstruction images derived from stored three-dimensional US data with real-time US images on the same US monitor and performed CEUS and real-time virtual sonography. Using a marking function, we drew a sphere marker along the target HCC nodule contour on pre-treatment US- multi-planar reconstruction images so that the automatically synchronized sphere marker represented the original HCC nodule contour on post-treatment real-time CEUS images. Ablation was considered sufficient when an avascular area with a margin of several millimeters in all directions surrounded the sphere marker on CEUS.
Results. This method was feasible and useful for assessing therapeutic effects in 13 consecutive patients with HCC who underwent RFA. In 2 patients who underwent multiple sessions of RFA, HCC-nodule portions requiring additional RFA were easily identified on US images.
Conclusions. This method using advanced US technologies will facilitate assessment of the effects of RFA on HCC.
3. Kudo M. New sonographic techniques for the diagnosis and treatment of hepatocellular carcinoma. Hepatol Res 2007; 37(Suppl 2): S193-9.
4. Okamoto E, Sato S, Sanchez-Siles AA, Ishine J, Miyake T, Amano Y, et al. Evaluation of virtual CT sonography for enhanced detection of small hepatic nodules: a prospective pilot study. AJR Am J Roentgenol 2010; 194: 1272-8.
5. Minami Y, Kudo M, Chung H, Inoue T, Takahashi S, Hatanaka K, et al. Percutaneous radiofrequency ablation of sonographically unidentifiable liver tumors. Feasibility and usefulness of a novel guiding technique with an integrated system of computed tomography and sonographic images. Oncology 2007; 72(Suppl 1): 111-6.
6. Kitada T, Murakami T, Kuzushita N, Minamitani K, Nakajo K, Osuga K, et al. Effectiveness of real-time virtual sonography-guided radiofrequency ablation treatment for patients with hepatocellular carcinomas. Hepatol Res 2008; 38: 565-71.
7. Kawasoe H, Eguchi Y, Mizuta T, Yasutake T, Ozaki I, Shimonishi T, et al. Radiofrequency ablation with the real-time virtual sonography system for treating hepatocellular carcinoma difficult to detect by ultrasonography. JClin Biochem Nutr 2007; 40: 66-72.
8. Nakai M, Sato M, Sahara S, Takasaka I, Kawai N, Minamiguchi H, et al. Radiofrequency ablation assisted by real-time virtual sonography and CT for hepatocellular carcinoma undetectable by conventional sonography. Cardiovasc Intervent Radiol 2009; 32: 62-9.
9. Numata K, Luo W, Morimoto M, Kondo M, Kunishi Y, Sasaki T, et al. Contrast enhanced ultrasound of hepatocellular carcinoma. World J Radiol 2010; 2: 68-82.
10. Minami Y, Kudo M, Hatanaka K, Kitai S, Inoue T, Hagiwara S, et al. Radiofrequency ablation guided by contrast harmonic sonography using perfluorocarbon microbubbles (Sonazoid) for hepatic malignancies: an initial experience. Liver Int 2010; 30: 759-64.
11. Masuzaki R, Shiina S, Tateishi R, Yoshida H, Goto E, Sugioka Y, et al. Utility of contrast-enhanced ultrasonography with Sonazoid in radiofrequency ablation for hepatocellular carcinoma. J Gastroenterol Hepatol 2011; 26: 759-64.
12. Numata K, Morimoto M, Ogura T, Sugimori K, Takebayashi S, Okada M, et al. Ablation therapy guided by contrast-enhanced sonography with Sonazoid for hepatocellular carcinoma lesions not detected by conventional sonography. JUltrasound Med 2008; 27: 395-406.
13. Bruix JSherman M. Management of hepatocellular carcinoma. Hepatology 2005; 42: 1208-36.
14. Kokudo NMakuuchi M. Evidence-based clinical practice guidelines for hepatocellular carcinoma in Japan: the J-HCC guidelines. J Gastroenterol 2009; 44(Suppl 19): 119-21.
15. Kim YS, Lee WJ, Rhim H, Lim HK, Choi DLee JY. The minimal ablative margin of radiofrequency ablation of hepatocellular carcinoma (> 2 and < 5 cm) needed to prevent local tumor progression: 3D quantitative assessment using CT image fusion. AJR Am J Roentgenol 2010; 195: 758-65.
16. Kim CK, Choi D, Lim HK, Kim SH, Lee WJ, Kim MJ, et al. Therapeutic response assessment of percutaneous radiofrequency ablation for hepatocellular carcinoma: utility of contrast-enhanced agent detection imaging. Eur J Radiol 2005; 56: 66-73.
17. Lu MD, Yu XL, Li AH, Jiang TA, Chen MH, Zhao BZ, et al. Comparison of contrast enhanced ultrasound and contrast enhanced CT or MRI in monitoring percutaneous thermal ablation procedure in patients with hepatocellular carcinoma: a multi-center study in China. Ultrasound Med Biol 2007; 33: 1736-49.
18. Kisaka Y, Hirooka M, Kumagi T, Uehara T, Hiasa Y, Kumano S, et al. Usefulness of contrast-enhanced ultrasonography with abdominal virtual ultrasonography in assessing therapeutic response in hepatocellular carcinoma treated with radiofrequency ablation. Liver Int 2006; 26: 1241-7.
19. Kisaka Y, Hirooka M, Koizumi Y, Abe M, Matsuura B, Hiasa Y, et al. Contrastenhanced sonography with abdominal virtual sonography in monitoring radiofrequency ablation of hepatocellular carcinoma. J Clin Ultrasound 2010; 38: 138-44.
20. Landmark KE, Johansen PW, Johnson JA, Johansen B, Uran SSkotland T. Pharmacokinetics of perfluorobutane following intravenous bolus injection and continuous infusion of sonazoid in healthy volunteers and in patients with reduced pulmonary diffusing capacity. Ultrasound Med Biol 2008; 34: 494-501.
21. Hiraoka A, Hirooka M, Koizumi Y, Hidaka S, Uehara T, Ichikawa S, et al. Modified technique for determining therapeutic response to radiofrequency ablation therapy for hepatocellular carcinoma using US-volume system. Oncol Rep 2010; 23: 493-7.