1. A method of contrast-enhanced computed tomography (CT) imaging, comprising: (a) repeatedly scanning a target region during a session, the scanning comprising performing a CT scan by emitting x-ray radiation at an applied power toward the target region, the applied power being a first power for a first scan; (b) monitoring an indicator of attenuation of radiation by a contrast-enhanced first structure within the target region; and (c) selecting the applied power for each of a plurality of scans, after a first scan, based on the attenuation indicated from a preceding scan in the session, wherein the applied power is selected by multiplying a maximum current by an exponential function based on the attenuation determined from the preceding scan.