OBJECTIVETo explore the feasibility of volume perfusion CT imaging to dynamically monitor and evaluate the response of rabbit VX2 soft-tissue tumor to antiangiogenic treatment.

METHODSTo establish an experimental animal model of VX2 soft tissue tumor on 20 New Zealand white rabbits. Twenty rabbits were randomly divided into 2 groups. The therapy group was treated with recombinant human endostatin (3 mg·kg⁻¹·d⁻¹) for 7 days, and the control group received saline in the same dose only. Four times of CT volume perfusion scan were performed before treatment and on the second, forth, seventh days of treatment, respectively. The value of blood flow (BF), blood volume (BV), mean transit time (MTT), and permeability (PMB) in the VX2 tumors were measured after scanning. The microvessel density (MVD) and expression of vascular endothelial growth factor (VEGF) in the tumors were determined using immunohistochemical staining.

RESULTSThe tumor volume of the therapy group was (1.36 ± 0.73) cm³ on the forth day of treatment and (1.69 ± 0.68) cm³ on the seventh day of the treatment. The tumor volume of the control group was (2.35 ± 0.62) cm³ on the fourth day of treatment and (3.87 ± 0.93) cm³ on the seventh day of the treatment (P < 0.05). On the seventh day of treatment, tumor necrosis ratio of the therapy group and the control group was (25.58 ± 5.51)% and (42.93 ± 4.34)%, respectively (P < 0.05). Comparing the perfusion parameters between the two groups on the same day, and the second, forth, seventh days of treatment, the value of PMB of the therapy group was (70.36 ± 23.46) ml·100 ml⁻¹·min⁻¹, (79.64 ± 13.68) ml·100 ml⁻¹·min⁻¹ and (84.76 ± 3.55) ml·100 ml⁻¹·min⁻¹, respectively, and that in the control group was (26.61 ± 6.47) ml·100 ml⁻¹·min⁻¹, (33.74 ± 16.47) ml·100 ml⁻¹·min⁻¹ and (30.47 ± 10.64) ml·100 ml⁻¹·min⁻¹, respectively (P < 0.05). The value of BF in the therapy group and control group was (71.19 ± 12.21) ml·100 ml⁻¹·min⁻¹ and (43.56 ± 12.21) ml·100 ml⁻¹·min⁻¹, respectively, on the seventh day of treatment (P < 0.05). The parameters on different days in the same group were compared. In the control group, the value of BF on the seventh day of treatment was significantly lower than that before and on the second and forth days of treatment (P < 0.05). However, in the therapy group, the value of PMB on the second, forth, and seventh days of treatment was significantly higher than that before treatment (P < 0.05). MVD of tumor in the control group was increased gradually, whereas increased on the first day and then decreased more in the therapy group. The VEGF expressions did not differ significantly between the experimental and control groups.

CONCLUSIONSVolume perfusion CT is helpful to quantify the tumor perfusion and evaluate the functional changes of tumor vasculature, and then evaluate the early therapeutic effect of antiangiogenic treatment.