Functional magnetic resonance imaging in an animal model of pancreatic cancer

AIM: To test the hypotheses that diffusion weighed (DW)- and transcatheter intraarterial perfusion (TRIP)- magnetic resonance imaging (MRI) can each be used to assess regional differences in tumor function in an animal pancreatic cancer model. METHODS: VX2 tumors were implanted in pancreata of 6 rabbits. MRI and digital subtraction angiography (DSA) were performed 3 wk following implantation. With a 2-French catheter secured in the rabbit's gastroduodenal artery, each rabbit was transferred to an adjacent 1.5T MRI scanner. DW- and TRIP-MRI were performed to determine if necrotic tumor core could be differentiated from viable tumor periphery. For each, we compared mean differences between tumor core/ periphery using a 2-tailed paired t -test (α = 0.05). Imaging was correlated with histopathology. RESULTS: Tumors were successfully grown in all rabbits, confirmed by necropsy. On DW-MRI, mean apparent diffusion coefficient (ADC) value was higher in necrotic tumor core (2.1 ± 0.3 mm²/s) than in viable tumor periphery (1.4 ± 0.5 mm²/s) (P < 0.05). On TRIP-MRI, mean perfusion values was higher in tumor periphery (110 ± 47 relative units) than in tumor core (66 ± 31 relative units) (P < 0.001). CONCLUSION: Functional MRI can be used to differentiate necrotic from viable tumor cells in an animal pancreatic cancer model using ADC (DW-MRI) and perfusion (TRIP-MRI) values.