In this study, Marr-Hildreth method applied on mostly two dimensional (2-D) images was extended in order to run on three dimensional (3-D) images. After the same method's 3-D version, the slicewise 2-D version, and the accelerated 3-D version reducing computational complexity were applied on knee MR images which were acquired from the Osteoarthritis Initiative database, the results obtained were compared, and the success of the 3-D Marr-Hildreth methods in detecting also the edges found by the slicewice 2-D Marr-Hildredth method was evaluated.