Real-time high-resolution compound imaging allows percutaneous initiation and surveillance in an orthotopic murine pancreatic cancer model.

Objectives: Orthotopic tumor models are regarded as being suitable for preclinical research on pancreatic cancer. The anatomic localization of the tumor in the retroperitoneum, however, provides little possibility for monitoring tumor growth.

Methods: To assess time-related changes in orthotopic tumor volume, we applied transabdominal high-resolution compound imaging to the murine pancreas. A 15-MHz ultrasound probe was used to determine the feasibility of real-time transabdominal high-resolution ultrasonography to initiate tumor growth by inoculation of pancreatic tumor cells into the pancreas and monitor tumor growth, as well as use as a tool for assessing response to chemotherapy.

Results: High-resolution ultrasound allows for precise tumor inoculation in the pancreas. Sonographic-evaluated tumor weight was found to be closely related to actual tumor weight (R = 0.97) measured during necropsy.

Conclusions: High-resolution real-time compound imaging substitutes killing of mice during longitudinal studies and can be used for minimizing animal consumption because each mouse can be followed in an experimental group rather than having to resort to euthanasia for tissue harvesting.