Dynamic contrast-enhanced magnetic resonance imaging assessment of residual tumor angiogenesis after insufficient microwave ablation and donafenib adjuvant therapy

Abstract

To analyze the correlation between dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) permeability parameters and serum vascular endothelial growth factor (VEGF) levels in a rabbit VX2 liver cancer model with insufficient microwave ablation (MWA), to observe the dynamic changes in residual tumor angiogenesis in the short term after MWA, and to assess the effectiveness of donafenib as adjuvant therapy. Forty rabbits with VX2 liver tumors were randomly divided into three groups: an insufficient MWA group (n = 15), a combined treatment group (n = 15) and a control group (n = 10). The dynamic changes in VEGF expression after MWA and the effectiveness of donafenib as adjuvant therapy were evaluated by DCE-MRI and serum VEGF levels before surgery and 1, 3, 7, and 14 days after surgery. The correlation between the volume translate constant (Ktrans) of DCE-MRI parameters and serum VEGF levels fluctuated after ablation, but the coefficient was always positive (all p < 0.001). Repeated-measures ANOVA revealed significant changes in the serum VEGF concentration (F = 40.905, p < 0.001; partial η² = 0.689), Ktrans (F = 13.388, p < 0.001; partial η² = 0.420), and tumor diameter in each group (F = 34.065, p < 0.001; partial η² = 0.648) at all five time points. Pairwise comparisons showed that the serum VEGF level, Ktrans value and tumor diameter in the insufficient MWA group and combined treatment group were significantly lower at 1 d than in the control group, but these values gradually increased over time (all p < 0.05). Ktrans and tumor diameter were significantly greater in the insufficient MWA group than in the control group at 14 days (all p < 0.05). The serum VEGF concentration, Ktrans, and tumor diameter were significantly lower in the combined treatment group than in the other two groups at 3, 7, and 14 days (all p < 0.05). Ktrans is positively correlated with the serum VEGF concentration. Ktrans and the serum VEGF concentration changed significantly after treatment with insufficient ablation or in combination with donafenib, and Ktrans may change faster. Insufficient MWA promotes the progression of residual tumors. Adjuvant treatment with donafenib is effective.

Keywords: DCE-MRI; Donafenib; Microwave ablation; VEGF; VX2.

Figure 1

(A) Dissociated tumor tissue; (B) tumor tissue suspension prepared and loaded into a syringe; (C) puncture needle used; (D) after the skin was prepared, the puncture needle was introduced along the predetermined route; (E) the tip of the needle was placed in the predetermined implantation position in the liver; (F) CT scan before ablation, which shows the formation of a low-density lesion at the corresponding location within the liver.

Figure 2

(A) T2WI image of the liver tumor before ablation, with the lesion showing a high signal; (B) DWI image before ablation, the lesion with restricted diffusion showing a high signal; (C) Axial CT image at the time of ablation, with the needle tip placed at the edge of the lesion and gas density visible in the ablation area; (D) T2WI image after ablation, with a decrease in signal in the ablated area and high signal in the residual tumor at its edge; (E) DWI image after ablation, the contour of the high signal area of the lesion can be seen as a defect (arrowhead), suggesting that the tumor is partially ablated; (F) T1WI enhancement image after ablation, residual tumor enhancement can be seen at the ablation margin.

Figure 3

Pseudocolor maps of Ktrans of lesions in rabbits in the insufficient MWA group obtained by DCE-MRI, with colors ranging from dark blue to dark red, the shades of which indicate the values of the parameters. (A) Before treatment, the tumor was predominantly hyperperfused (yellow and red). (B) One day after insufficient MWA, perfusion in the ablated area was reduced, but hyperperfusion was still observed in the residual tissue. (C) Seven days after MWA, the residual tumor was enlarged, and perfusion increased. (D) 14 days after MWA, the area of hypoperfusion caused by ablation was markedly reduced, perfusion further increased in the ablated area, and the residual tumor increased in size.

Figure 4

Mean curves of serum VEGF and Ktrans and tumor diameter.