Ablation margin assessment of liver tumors with intravenous contrast-enhanced C-arm computed tomography

Figure 1 A 43-year-old woman with a 13-mm hepatocellular carcinoma in hepatic segment IV. A: A venous-phase image from contrast-enhanced multidetector computed tomography (MDCT) prior to treatment shows a hypoattenuated tumor in hepatic segment IV (arrow); B: A venous-phase MDCT image in which the tumor size has been measured in vertical and horizontal directions and the tumor location has been determined by the distance from the left portal vein; C: An intravenous contrast-enhanced C-arm computed tomography image obtained just after radiofrequency ablation (RFA) shows sufficient ablative margins in all 4 directions (ventral margin, 1.8 mm; dorsal margin, 8.8 mm; right lateral margin, 20.5 mm, left lateral margin, 10.3 mm) even though the ventral ablative margin is less than 5 mm due to the adjacent liver border; D: A portal-phase image from contrast-enhanced MDCT obtained 7 d after the RFA procedure shows an almost identical configuration with ablative margins (ventral margin, 2.0 mm; dorsal margin, 8.0 mm; right lateral margin, 17.0 mm; left lateral margin, 10.0 mm) comparable to those depicted in the C-arm CT image.

Figure 2 A 59-year-old woman with a 15-mm hepatocellular carcinoma in hepatic segment III. A: An arterial-phase image from contrast-enhanced multidetector computed tomography (MDCT) prior to treatment shows a well-enhanced tumor in hepatic segment III (arrow); B: An arterial-phase MDCT image in which the tumor size has been measured in the vertical and horizontal directions and the tumor location has been determined by the distance from the left portal vein; C: An intravenous contrast-enhanced C-arm computed tomography (CT) image obtained just after radiofrequency ablation (RFA) reveals insufficient ablative margins in the right lateral (1.1 mm) and dorsal (1.9 mm) directions. Indentations caused by the left hepatic vein and the portal vein adjacent to the tumor might disrupt sufficient ablation. The ventral (11.3 mm) and left lateral (5.4 mm) ablative margins appear sufficient; D: A portal-phase image from contrast-enhanced MDCT obtained 7 d after RFA shows an almost identical configuration with comparable ablative margins (ventral margin, 11.0 mm; dorsal margin, 3.0 mm; right lateral margin, 2.0 mm; left lateral margin, 6.0 mm) to those evaluated on C-arm CT image.