Arterial-phase contrast-enhanced ultrasonography for evaluating anti-angiogenesis treatment: a pilot study

To verify whether arterial-phase contrast-enhanced ultrasonography (CEUS) of tumor parenchymal tissue is useful for evaluation of anti-angiogenesis agents.

Rabbits with liver tumor were subjected to CEUS, and images of the nodular maximal diameter in vascular phase were recorded. Image analysis was performed to plot the time intensity curve (TIC) at the tumor parenchyma, which set the diameter of the region of interest of intensity measurement. The TIC was calculated to obtain the time to peak intensity (TPI) and the magnitude of PI. Rabbits were randomly assigned to a treatment group with sorafenib and a control group. Two weeks later, the same ultrasound examination was repeated followed by pathological testing to assess the effect of sorafenib on the liver tumor.

In four rabbits in the treatment group, the rate of change of tumor size was decreased compared with that of the control (the rate 2.3 vs 7.9, P = 0.02). The TPI of the treatment group elongated significantly (the rate 3.1 vs 1.1, P = 0.07 for SonoVue, 2.0 vs 0.88, P = 0.09 for Sonazoid). The magnitude of PI showed no significant changes. In pathological examination, capillary diameters in the treatment group were significantly smaller than those in the control group (26.4 vs 42.8 μm, P = 0.013).

Analysis of the TIC in the arterial phase of tumor tissue could evaluate the efficacy of anti-angiogenesis drug treatment in liver tumor.