Can I Keep Blood Flowing Through A Detached Head? -beter Explained?

I’m using MR-perfusion to determine blood flow in the brain. I need to compare my technique with another method. (CT- PET) The methods require contrast soluiton or radiation dose. I’m thinking of setting up an experiments in which a deteched (human/pigs) head is perfused. Is this possible? Can I keep the flow constant? The blood flow is what I am measuring. I’m thinking of persusion with water -and adding contrast solution to do the measurement?
Is this technically/theoretically possible?
Can I keep blood/water flowing through a detached (human or pigs) head? What’s important is that the flow stays constant. Will there be very fast coagulation? Can I pump through water?
Thanks.