Case 378: Radiofrequency Ablation (RFA)

Diagnostic Category:

Clinical Presentation:

65 year-old man with history of colorectal carcinoma metastasis in the right hepatic lobe. Surveillance 12 months following radiofrequency ablation performed in another institution.

US: Local tumor recurrence of hypervascular metastasis with washout on CEUS

Imaging Findings:

Gray-scale ultrasound demonstrates tumor recurrence (arrow) poorly distinguishable from the ablation zone in segment 5, since both demonstrate a hypoechoic "halo-sign". Color Doppler does not show hypervascularity to aid in the distinction of metastasis and treated area (arrow).

Early arterial phase contrast enhanced ultrasound (CEUS) demonstrates transient hypervascularity followed by rapid contrast washout of metastasis (arrows), clearly demarcating local recurrence from non-enhancing ablation zone.

CEUS was used to distinguish precise extent of recurrent tumor portion and to guide the ablation probe for re-ablation.