Abstract
Purpose: :
To evaluate the utility of in vivo imaging of a mouse model of intraocular melanoma utilizing high frequency ultrasound and a microbubble contrast agent.
Methods: :
Six 12 week old C57Bl6 mice were inoculated into their right eyes with a 1X105 aliquot of B16LS9 melanoma cells. Group 1 (n=3) was treated with 250µg/100µl bevacizumab IP at day 2 and group 2 received an equal volume of IP PBS. The eyes were imaged with Visual Sonics Vivo 2100® high frequency ultrasound with MicroMarker contrast agent at 7 days post inoculation with in vivo determination of melanoma tumor volume and relative blood volume. The eyes were enucleated at 7 days post inoculation and with sections through the centers of the tumors obtained. The histologic tumor areas were determined with Image J software. The in vivo and in situ measurements were compared.
Results: :
Utilizing Visual Sonics Vivo 2100® high frequency ultrasound with MicroMarker contrast agent, the average tumor volume of ocular melanoma in mice treated with bevacizumab versus PBS was 22.56±6.40 mm3 and 29.26 ±0.78 mm3,, respectively (p=0.04). Utilizing histologic measurment, the average largest area in mice treated with bevacizumab versus PBS was 518925.7±118242.6 pixel2 and 1067844±308489.9 pixel2, respectively (p=0.02). The correlation coefficient of the sonographic volume and histologic area was 0.79 and a Wilcoxon two-sample test showed no significant difference (p=0.69). Relative blood volume within the tumor demonstrated sonographically with the contrast agent corresponded with histologic tumor vascularity.
Conclusions: :
There was good correlation between in vivo and in situ tumor volume and area measurements. Color Doppler imaging with MicroMarker Contrast Agent imaging assessment of relative blood volume corresponds with histologic tumor vascularity. High frequency ultrasound may be used to evaluate for in vivo treatment effect in a mouse model of intraocular melanoma, obth in terms of tumor volume and relative blood volume.
Keywords: melanoma • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • pathology: experimental