Radiofrequency Ablation After Arterial Injection of Miriplatin–Iodized Oil Suspension Into Swine Liver: Ablative Zone Size and Tissue Platinum Concentration

Abstract

To evaluate whether arterial injection of miriplatin-iodized oil suspension facilitates ablative zone expansion by radiofrequency (RF) ablation using a Cool-Tip electrode and to provide effective tissue platinum concentration in the normal swine liver. RF ablation was performed at three sites of each liver. RF ablation alone was performed in two animals (control). Ablation was performed after arterial injection of iodized oil (iodized-oil group) or a miriplatin-iodized oil suspension (miriplatin group) in two animals each. Long- and short-axis diameters of the ablative zone were measured. In the miriplatin group, tissue platinum concentrations were measured in the ablative, surrounding hyperemic rim, and nonablative zones. The mean long- and short-axis diameters of ablative zones were 27.0 ± 3.1 and 18.0 ± 0.6 mm in the control. Although the long-axis diameter (30.2 ± 2.8 mm, p = 0.07) showed no significant expansion, the short-axis diameter (20.8 ± 2.6 mm, p = 0.04) was significantly expanded more in the iodized-oil group than in the control. Ablative zone sizes were largest in the miriplatin group. The long-axis diameter (33.5 ± 2.4 mm, p = 0.01) was significantly larger than that in the control. The short-axis diameter (27.2 ± 1.9 mm, p = 0.004) was significantly larger than that of the iodized-oil group. Tissue platinum concentrations showed an effective antitumor effect (≥9 μg/g) in ablative (16.5 ± 5.7 μg/g), surrounding hyperemic rim (18.0 ± 5.1 μg/g), and nonablative zones (mean 22.2 ± 5.7 μg/g) (p = 0.21). Arterial injection of miriplatin-iodized oil suspension can expand the ablative zone size and provide effective tissue platinum concentration on tumor control in the ablative zones and their surrounding hyperemic rim.