Methods, protocols and systems are provided for multi-modality imaging based on
pharmacokinetics of an
imaging agent. An
imaging agent is introduced into a subject, and is permitted to collect generally in a
region of interest (ROI) in the subject until attaining a pseudo-
steady state (PSS) distribution within the ROI. The
imaging agent records a first functional state of the ROI at a given point in time. A first image
data set is obtained with a first imaging modality during a first
acquisition time interval that occurs prior or
proximate in time with the PSS time interval. The subject is transferred from the first imaging modality to a second imaging modality during a transfer time interval that overlaps the PSS time interval. Once transfer is complete, a second image
data set is obtained with the second imaging modality during a second
acquisition time interval that also overlaps the PSS time interval in which the imaging agent maintains the PSS distribution in the ROI. In accordance with a protocol, the transfer time interval and second
acquisition time interval substantially fall within the PSS time interval. The imaging agent collects in the ROI during an uptake time interval which may or may not precede the time interval during which first imaging modality obtains at least a portion of the first image
data set. The second image data set is obtained while the imaging agent persists in the ROI at the PSS distribution reflective of the first functional state even after the ROI is no longer in the first functional state.