Fig 1.
Timeline of the experimental set-up from tumor cell implantation to tumor explantation with immunohistochemical analysis.
Fig 2.
Representative CEUS images of a rat after 7 days of regorafenib therapy with a subcutaneous tumor xenograft (green) and blood volume parameter map with a ROI in a hypervascular vital tumor site of the outer rim (yellow). Corresponding signal-intensity-versus-time-curves are shown below.
Fig 3.
Representative CEUS images of a rat with a subcutaneous tumor xenograft (white arrows) under treatment.
Therapy group (red) and control group (blue) at baseline and follow-up. Left side: early vascular phase with BR55 as a functional imaging biomarker; right side: late phase of VEGFR2-specific binding with BR55 as a molecular imaging biomarker 8 minutes after contrast injection. Note the significant lower number of circulating microbubbles in the early vascular phase as well as the significant lower number of bound microbubbles in the late phase at follow-up in the therapy group, compared to baseline and compared to the control group.
Fig 4.
Column charts of WiAUC in the therapy and control group at follow-up.
Note the significant difference (p < 0.05) between the mean values of WIAUC between the therapy and the control group at the follow-up.
Table 1.
Individual functional CEUS values.
Fig 5.
Column charts of SI10min in the therapy and control group at follow-up.
Note the significant difference (p < 0.05) between the mean values of SI10min between the therapy and the control group at the follow-up.
Table 2.
Individual molecular CEUS values.
Table 3.
Individual DCE-MRI values.
Fig 6.
Representative immunohistochemical stainings.
CD31 (A, B; microvascular density), Ki-67 (C, D; cell proliferation), TUNEL (E, F; apoptosis) and VEGFR2 expression (G,H) in the therapy (left column: A, C, E, G) and in the control group (right column: B, D, F, H). Note the significant lower (p < 0.01) microvascular density, tumor cell proliferation and VEGFR2 expression and the significant higher (p < 0.01) apoptosis rate in the therapy group. Scale bar in images represents 100 μm.
Table 4.
Individual immunohistochemical values.
Table 5.
Correlations between functional CEUS values and immunohistochemistry.
Fig 7.
Line regression analysis for the correlation between CEUS parameter of VEGFR2-specific binding and immunohistochemical VEGFR2 expression.
Note the significant correlation between the values of SI8min and the number of VEGFR2 positive stained vessels (Spearman´s ρ = 0.66, p = 0.003) for the therapy and the control group.
Table 6.
Correlations between molecular CEUS values and immunohistochemistry.