In a method and magnetic resonance apparatus for segmenting image data of an examination object, raw data of the examination object are achieved with the operation of a magnetic resonance scanner. Quantitative image data of the examination object are then calculated in a processor from the raw data. At least one physical variable of the examination object is quantitatively ascertained pixelwise and is displayed. The quantitative image data are segmented for identification of predetermined objects in the quantitative image data, and displayed in a display unit.