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

Abstract

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.

Advanced ultrasonography technologies to assess the effects of radiofrequency ablation on hepatocellular carcinoma

“…described the usefulness of RVS using 3DUS data in predicting the effects of RFA on HCC 21. The RVS system runs on a workstation connected to a US machine (EUB7500; Hitachi Medical Corporation).…”

Iodine quantification with dual-energy CT: phantom study and preliminary experience with VX2 residual tumour in rabbits after radiofrequency ablation

“…This assessment is commonly performed after 1 month or more with contrast-enhanced helical CT consisting of pre-contrast, arterial, portal and delayed phase scanning [6]. However, assessment of the accuracy of completeness of the RFA at immediate or < 6-month followup CT or MRI has inevitahle limitations hecause enhancement of inflammatory reaction to the thermal injury makes accurate evaluation difficult [7][8][9]. The henign periahlational reactive tissue, which represents inflammatory reaction, can emerge immediately after ahlation and can last as long as 6 months after ahlation [8].…”

Immediate evaluation and guidance of liver cancer thermal ablation by three-dimensional ultrasound/contrast-enhanced ultrasound fusion imaging

“…In some previous reports, 3 D US -US fusion imaging was used in the RFA procedure. When the ablative hyperechoic zone expanded over the tumour with the AM, the RFA procedure was terminated [14,19]. However, CEUS is more accurate than US in the assessment of the ablation zone [20,21].…”

“…CEUS is recognised as an important method for the assessment of the immediate treatment response to liver ablation according to the microvascular perfusion of the ablation zone [12]. Three-dimensional (3D) US has been successfully used in thermal ablation to provide more intuitive spatial structure information [10,13,14]. The fusion imaging technique is a useful tool for precise image comparison [6].…”