Disclosed aspects relate to the acquisition and processing of projection data using temporal characteristics of the imaged volume, such as the uptake and clearance of a contrast agent within the volume. Such temporal aspects may be used in the acquisition process, such as to differentially acquire images based on the propagation of the contrast agent. In addition, such temporal aspects may be used in the processing of projection data to generate differential projections (e.g., first or second order subtraction projections), compound projections synthesized using the absolute or relative maximum opacity values observed over time for a region of interest, or interpolated projections synthesized using observed opacity values at known or fixed time intervals and a derived peak opacity time.