A method and system for displaying a physiologic waveform. The method and system acquire positron emission tomography (PET) coincidence event data of an object of interest. The method and system further select a subset of the PET coincidence event data corresponding to a time window and apply a multivariate data analysis technique to the subset of the PET coincidence event data. The method and system also generate a physiologic waveform based on the multivariate data analysis, and display the physiologic waveform on a display.