A probe unit (100) including a magnet (102, 103) generates a static magnetic B0 field in an examination region and a RF coil (105). An input-output module (201) includes a transmitter (203) which controls the RF coil (105) to excite resonance and cause echoes (210) and a receiver (204) which demodulates and digitizes the echoes (210). A data processing module (206) includes at least one processor programmed to calculate a T2 relaxation distribution plot from a digitized echo (210) train, calculate a first area under the fat peak on the T2 distribution plot, calculate a second area under a water peak on the T2 distribution plot, and normalize the first and second area to determine a fat-to-water ratio.