Ferucarbotran-enhanced MR imaging of the radiofrequency ablation zones in the normal rabbit liver: comparison with the conventional MR imaging

We wanted to evaluate the findings of ferucarbotran-enhanced MR imaging of the radiofrequency (RF) ablation zones in normal rabbit livers and we compared the findings with the conventional MR imaging. RF ablation zones were created in the livers of 12 rabbits in vivo by using a 17-gauge internally cooled electrode with 1-cm active tip, and RF energy (maximum power: 30 Watt) was applied for three minutes. There rabbits were sacrificed immediately and then at three days, two weeks and six weeks after RF ablation. Before sacrifice, the T1-and T2-weighted images (WI) and the ferucarbotran-enhanced T2WIs were obtained and compared regarding the signal intensity of ablation zone, the laminar pattern of the signal intensity and the contrast-to-noise ratio (CNR) of the ablation zone to the liver parenchyma. On T1-and T2WIs, the RF ablation zones showed two to four laminar patterns of signal intensity according to the time. Meanwhile, on the ferucarbotran-enhanced T2WIs, the RF ablation zones showed high signal intensity without a laminar pattern regardless of time. The CNRs of the ablation zones to the liver parenchyma on the ferucarbotran-enhanced T2WIs (18.2 ± 5.9) were significantly higher than those of the TIWIs (1.6 ± 1.5) and T2WIs (2.7 ± 1.9) (ρ < 0.05). On the ferucarbotran-enhanced T2WIs, the RF ablation zones showed high signal intensity without a distinct laminar pattern and significantly higher lesion conspicuity than did the conventional. T1-and T2WIs. Therefore, the ferucarbotran-enhanced T2WIs showed the RF ablation zone more accurately and clearly than do the conventional T1-and T2WIs