A method is provided that includes acquiring, with a detector defining a field of view (FOV), emission imaging data of an object over the FOV. The method also includes determining, with one or more processing units, a volume of interest (VOI) of the emission imaging data, wherein the VOI defines a volume smaller than an imaged volume of the object. Further, the method includes performing, with the one or more processing units, a multivariate data analysis on the VOI to generate a waveform for the VOI. Also, the method includes determining, with the one or more processing units, an amount of motion for at least the VOI based on the waveform. The method further includes displaying, on a display unit, at least one of the amount of motion or an image reconstructed based on the emission imaging data.