Complications of Radiofrequency Ablation of Liver Tumors: Hematoma

Figure 1: Axial CT image before radiofrequency ablation of a liver metastasis (star) is shown.
Figure 2: Axial CT image immediately after the RFA shows a small subcapsular hematoma anterior to the right hepatic lobe (arrows). Note hyperattenuation change at the tumor site (star), which is expected after the RFA.

Vascular complications of RFA

1. Portal vein thrombosis (0.7%)
2. Subcapsular hematoma (0.7%)
3. Hepatic vein thrombosis
4. Hepatic infarction

Facts

• Thrombosis of vessel occurs as a result of 'heat-sink' effect to the flowing blood. Smaller caliber vessels are prone to thrombose due to thermal damage from RF ablation
• On US, or CT, thrombosis is visualized as filling defects
• Hepatic parenchyma may show segmental enhancement peripheral to the affected veins
• Most thrombosis is self limited
• Subcapsular hematoma usually is related to placement of electrodes or underlying coagulopathy.

Reference:

Akahane M, Koga H, Kato N, et al. Complications of percutaneous radiofrequency ablation for hepatocellular carcinoma: imaging spectrum and management. Radiographics 2005; 25:S57-S68.