1. A method for MRI imaging, the method comprising: after administering a contrast agent, repeatedly acquiring image data, including modulating contrast enhancement of the contrast agent in time by applying a time-varying radio frequency saturation pulse to said contrast agent, the time-varying radio frequency saturation pulse having a known pulse time course; reconstructing the image data into image pixels or voxels of at least one of images and a part of the images with contrast enhancements; determining an intensity time course of the at least one of the images and the part of the images with contrast enhancement; correlating said intensity time course with the pulse time course of the applied time-varying radio frequency saturation pulse for each image pixel or of the reconstructed images or parts of the images with contrast enhancement to determine a presence of said contrast agent in each image pixel or voxel; and displaying on a display device at least one of the reconstructed images, the part of the images with contrast enhancement, and a depiction of the presence of contrast agent for a selected image pixel or voxel.