Abstract: There is provided a method of automatically segmenting a magnetic resonance (MR) image, comprising: segmenting a residual breast from an input MR image depicting the residual breast with implant after surgical removal of breast tissue, wherein the segmentation of the residual breast includes breast tissue remaining after the surgical removal, feeding the segmented residual breast into a fibroglandular tissue (FGT) segmentation ML model, and obtaining a segmentation of FGT from the segmented residual breast as an outcome of the FGT segmentation ML model. Optionally, the FGT segmentation ML model is trained on a FGT segmentation training dataset of FGT segmentation records, each FGT segmentation record including a MR image of a segmented whole breast of a control subject that excludes an implant and on which no surgical removal of breast tissue has been performed, and a ground truth comprising a segmentation of the FGT depicted in the segmented whole breast.