Patent ID: 7081092

Claim:
A method for determining an exchange rate for a moving fluid in a target region comprising the steps of: introducing undisrupted imaging agent into a moving fluid, said moving fluid being present in a target region; allowing undisrupted imaging agent to penetrate said target region; disrupting the imaging agent in the target region to provide disrupted imaging agent having a signal level less than that provided by undisrupted imaging agent; allowing the moving fluid to transport undisrupted imaging agent from outside the target region into the target region; interrogating the target region with a monitor capable of registering the signal level whereby an increase in signal level corresponding to an increase in undisrupted imaging agent is observed; calculating the exchange rate of moving fluid in the target region based on the observed increase in signal level; comparing the exchange rate of moving fluid in the target region based on the observed increase in signal levels are measured at different times to ascertain the increase in signal per unit time; dividing the increase in signal per unit time by a measured or derived maximum signal value to obtain the fluid exchange rate, and, multiplying the obtained fluid rate exchange rate by the fluid content of said target region to obtain a perfusion rate for said target region.