1. A method of analyzing image data of a subject with an imaging system, comprising: acquiring initial image data of a selected portion of the subject from an imaging system positioned around the subject; constructing a first three-dimensional model of the selected portion of the subject using the acquired image data; receiving into a processor system an input regarding a procedure performed on a portion of the subject; acquiring discriminatory discrete location image data of the subject at locations limited to the portion of the subject effected by the inputted procedure; executing instructions with a processor to determine a comparative movement of a gantry and a detector that is less than the movement of the detector while acquiring the initial image data of the subject that includes instructions for moving the gantry and the detector to acquire the comparative image data; comparing the acquired discriminatory discrete location image data to at least a portion of the constructed first three-dimensional model of the portion of the subject; identifying specific regions having a change between the acquired discriminatory discrete location image data and a simulated projection image data from the first constructed three-dimensional model of the portion of the subject; acquiring additional comparative image data of identified specific regions of a threshold change; and constructing a comparative model of the subject after the performed procedure; wherein acquiring the additional comparative image data includes acquiring less image data of the subject than with the acquired initial image data of the subject; wherein acquiring less image data includes exposing the subject to less x-ray radiation than while acquiring the initial image data of the subject; wherein constructing the comparative model of the subject after the performed procedure includes changing the three-dimensional model with the acquired additional comparative image data.