A method for generating time-resolved 3D medical images of a subject by imparting temporal information from a time-series of 2D medical images into 3D images of the subject. Generally speaking, this is achieved by acquiring image data using a medical imaging system, generating a time-series of 2D images of a ROI from at least a portion of the acquired image data, reconstructing a 3D image substantially without temporal resolution from the acquired image data, and selectively combining the time series of 2D images with the 3D image. Selective combination typically involves registering frames of the time-series of 2D images with the 3D image, projecting pixel values from the 2D image frames “into” the 3D image, and weighting the 3D image with the projected pixel values for each frame of the time-series of 2D images. This method is particularly useful for generating 4D-DSA images (that is, time-resolved 3D-DSA images) from a time-series of 2D-DSA images acquired via single plane or biplane x-ray acquisitions with 3D images acquired via a rotational DSA acquisition. 4D-DSA images can be generated either by using multiple injections or by using a single injection by combining a time-series of 2D-DSA images generated from individual projections from a rotational x-ray acquisition with a 3D image reconstructed from substantially all of the projection views acquired during the rotational x-ray acquisition. These DSA images may have a spatial resolution on the order of 5123 pixels and a temporal resolution of about 30 frames per second, which represents an increase over traditional 3D-DSA frame rates by a factor of between 150 and 600.