Dynamic Contrast-Enhanced MR Imaging Evaluation of Perfusional Changes and Ablation Zone Size after Combination Embolization and Ablation Therapy

Purpose: The objectives of this study were to assess the utility of dynamic contrast-enhanced magnetic resonance (MR) imaging in quantifying parenchymal perfusional changes after embolization and to characterize the association between pharmacokinetic (PK) parameters and final microwave ablation volume.Materials and Methods: PK parameters from dynamic contrast-enhanced MR imaging were used to quantify perfusional changes in the liver after transarterial embolization of the right or left lobe in a swine liver model (n = 5). Each animal subject subsequently underwent microwave ablation (60 W for 5 minutes) of the embolized and nonembolized liver lobes. Changes in PK parameters from dynamic contrast-enhanced MR imaging were correlated with their respective final microwave ablation volumes in each liver lobe.Results: Microwave ablation volumes of embolized liver lobes were significantly larger than those of nonembolized liver lobes (28.0 mL & PLUSMN; 6.2 vs 15.1 mL & PLUSMN; 5.2, P < .001). PK perfusion parameters were significantly lower in embolized liver lobes than in nonembolized liver lobes (Ktrans = 0.69 min-1 & PLUSMN; 0.15 vs 1.52 min-1 & PLUSMN; 0.37, P < .001; kep = 0.69 min-1 & PLUSMN; 0.19 vs 1.54 min-1 & PLUSMN; 0.42, P < .001). There was a moderate but significant correlation between normalized kep and ablation volume, with each unit increase in normalized kep corresponding to a 9.8-mL decrease in ablation volume (P = .035).Conclusions: PK-derived parameters from dynamic contrast-enhanced MR imaging can be used to quantify perfusional changes after transarterial embolization and are directly inversely correlated with final ablation volume.