Figure 2.

Image feature of the halo ground glass opacity. (A) A 46-year-old woman with colorectal cancer has a new solid 5 mm metastatic tumor at the posterior aspect of the right upper lobe (arrow) before MWA; (B) the antenna is placed through the center of the targeted nodule and shows a surrounding halo ground glass opacity during the procedure; (C) after removal of the antenna, there is an apparent hypodense track inside the tumor in addition to the halo; (D) follow up non-contrast CT one year after MWA shows focal fibrosis and disappearance of the metastatic nodule, indicating complete tumor ablation.