Prediction of the ablated area by the spread of microbubbles during radiofrequency ablation of hepatocellular carcinoma

Nouso, Kazuhiro; Shiraga, Kunihiro; Uematsu, Setsuko; Okamoto, Ryoichi; Harada, Ryo; Takayama, Shoko; Kawai, Wakako; Kimura, Shigeru; Ueki, Toru; Okano, Nobuaki; Nakagawa, Masahiko; Mizuno, Motowo; Araki, Yoshihiro; Shiratori, Yasushi

doi:10.1111/j.1478-3231.2005.01145.x

Cited by 25 publications

(29 citation statements)

References 19 publications

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“…Some reports suggest that automated pulsing at a higher RF current with internally cooled electrodes has further increased coagulation necrosis compared to continuous RF application in liver tissues [8, 17]. On the other hand, a modified pulsed algorithm was used recently which depends on a gradual stepwise increase of the RF current at a fixed duration by manually adjusting the power setting until rapid tissue impedance is reached followed by a period of low-energy deposition [3, 14, 15]. Achievement of maximum tissue impedance is related to the heat produced by the RF current and the subsequent coagulation, which represents complete necrosis over the thermal area.…”

Section: Discussionmentioning

confidence: 99%

“…For the manual algorithm [3, 14, 15], the power output was initially set at 60 W then increased manually at 20 W per minute to reach up to 120 W. Power is maintained at this level until rapid tissue impedance is achieved. The power is then manually turned off for 15 s. Afterwards, the power output is restarted with a 20-watt reduction from the previous highest reading and gradually increased by 20 W/min until rapid tissue impedance is observed.…”

Section: Methodsmentioning

confidence: 99%

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Treatment of Hepatocellular Carcinoma Using Internally Cooled Electrodes

Y.¹,

Lin²,

Lin³

et al. 2007

Oncology

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Objectives: To compare the effectiveness of modified automated and manual pulsed radiofrequency (RF) algorithms using internally cooled electrodes for hepatocellular carcinoma (HCC). Methods: Seventy-seven treatment-naive cirrhotic patients with 102 HCC (≤4 cm) underwent 109 sessions of ultrasound-guided percutaneous RF ablation using a 17-gauge, 20-cm-long, single internally cooled electrode. Patients were assigned alternatively: 40 patients to the modified automated algorithm group and 37 patients to the manual algorithm group. The mean tumor diameters were 2.34 ± 0.9 and 2.25 ± 0.7 cm in the automated and manual groups, respectively (p = 0.56). Primary technique effectiveness and local tumor progression were compared between the two groups. Results: More overlapping ablations (n = 112) were required in the manual than in the automated group (n = 82) to achieve similar primary technique effectiveness rates of 96.1 and 94.1%, respectively. After a mean follow-up period of 26.7 ± 1.1 months, the local tumor progression rates at 12 and 18 months were 4 and 20% in the manual group and 12 and 24% in the modified automated group (p = 0.3). Only tumors >3 cm were independently associated with local tumor progression (odds ratio 1.25; 95% CI 1.06–2.34, p = 0.03). Conclusions: The manual algorithm requires more overlapping ablations and treatment sessions in order to achieve similar primary technique effectiveness and local tumor progression rates compared with the modified automated algorithm.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Treatment of Hepatocellular Carcinoma Using Internally Cooled Electrodes

Y.¹,

Lin²,

Lin³

et al. 2007

Oncology

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“…The spread of the hyperechoic area by ablation was reported to be useful to estimate the boundaries of the ablated area (22,23), while Nouso et al reported that the size of the area of hyper-echogenicity at 5 min after ablation and that of the defect observed by CEUS 3-5 days after RFA were closely correlated (24). These findings led us to use hyper-echoic microbubbles at 5 min after ablation for determining the area of necrosis.…”

Section: ------------------------------------------------------------mentioning

confidence: 99%

Modified technique for determining therapeutic response to radiofrequency ablation therapy for hepatocellular carcinoma using US-volume system

Hiraoka

Hirooka²,

Hidaka³

et al. 2009

Oncol Rep

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Abstract. In radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC), microbubbles appearing during the procedure make it difficult to determine effectiveness with ultrasonography (US) imaging. We developed a modified US-volume system and evaluated its efficacy for demonstrating response to therapeutic RFA. Our US-volume system displays multiplanar reconstruction (MPR) images providing a synchronized view with a US image along with past USvolume data in real-time side-by-side on a personal computer. Seventy-eight patients (94 nodules) were enrolled, of whom 35 (47 nodules) were evaluated using this system (US-volume group) and compared to the other 43 (47 nodules) examined before development of our system (control group). All nodules were clearly depicted by US. If the shortage of margin was predicted with US-volume system, we performed additional needle insertion. Tumor necrosis following RFA was graded by dynamic computed tomography as follows: Grade A, necrotic area surrounded in all directions with an adequate margin (≥5 mm); Grade B, necrotic area surrounded in all directions, though some margin areas <5 mm; and Grade C, residual tumor or necrotic area smaller than the target tumor. In the US-volume group, the average tumor size was not smaller than that in the control (15.9±4.9 vs. 16.0±4.3 mm) and adequate margins were obtained (Grade A, B, C, 45/1/1 vs. 35/8/4; P<0.01). Further, there was a significant reduction in numbers of RFA sessions as compared to the control (1.03±0.17 vs. 1.12±0.32; P<0.01). In HCC patients undergoing RFA, our modified US-volume system accurately demonstrated therapeutic response, which led to a reduced number of RFA sessions.

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“…After the ablation, we evaluated whether the overlaid tumor was completely encompassed with the spreading hyperechoic bubbling area [12,13]. If an overlaid tumor was protruding from the bubbling area, additional ablation was performed until it was completely within the bubbling area.…”

Section: Methodsmentioning

confidence: 99%

Usefulness of the Extracted-Overlay Function in CT/MR-Ultrasonography Fusion Imaging for Radiofrequency Ablation of Hepatocellular Carcinoma

Makino

Imai²,

Igura³

et al. 2013

Dig Dis

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Objectives: We developed a novel technique of the extracted-overlay function in CT/MR-ultrasonography (US) fusion imaging for radiofrequency ablation (RFA), in which only a tumor extracted from CT/MR images with a virtual ablative margin of arbitrary thickness is overlaid on US. The usefulness of this function is investigated in this preliminary report. Methods: The volume data of the extracted tumor with a virtual ablative margin were created on an image-processing workstation, and transported into a US unit equipped with a CT/MR-US fusion imaging system. After the positional registration of US and transported images, the extracted tumor with an ablative margin could be overlaid on US. In RFA, using this function, an electrode was inserted targeting the overlaid tumor with an ablative safety margin of 5 mm on US, and the treatment effect was evaluated by dynamic CT. Treatment results of 23 consecutive hepatocellular carcinomas (HCCs) that underwent RFA using this function were retrospectively analyzed. Results: Complete tumor ablation was achieved in 22 (95.7%) and 1 (4.3%) HCCs in 1 and 2 treatment sessions, respectively. Conclusions: Due to the visualization of an extracted tumor with an ablative safety margin on a US image, even during and after ablation, this function is useful for treatment planning and guidance of RFA.

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Prediction of the ablated area by the spread of microbubbles during radiofrequency ablation of hepatocellular carcinoma

Abstract: The observation of microbubbles during RFA can predict the ablated area and might be useful to prevent the unfavorable ablation of adjacent organs and vessels.

Cited by 25 publications

References 19 publications

Treatment of Hepatocellular Carcinoma Using Internally Cooled Electrodes

Treatment of Hepatocellular Carcinoma Using Internally Cooled Electrodes

Modified technique for determining therapeutic response to radiofrequency ablation therapy for hepatocellular carcinoma using US-volume system

Usefulness of the Extracted-Overlay Function in CT/MR-Ultrasonography Fusion Imaging for Radiofrequency Ablation of Hepatocellular Carcinoma

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