A magnetic resonance imaging system (3) includes a sequence control unit (18), a sampling unit (26), and a control unit (24). The sequence control unit (18) controls a magnetic resonance scanner (4) to acquire compressed magnetic resonance data from an imaged region of a subject. The sampling unit (26) determines a change in a concentration of a contrast agent present in the image region of the subject based on magnetic resonance signals received by a radio frequency receiver. The control unit (24) adjusts a degree of compression of the acquired magnetic resonance data based on the determination made by the sampling unit (26).
